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Due to the widespread resistance of small ruminant gastrointestinal nematodes (GIN) against anthelmintic drugs the established control strategies need to get adapted, aiming to reduce their high dependence from chemical drugs. Host-specific development of GIN can be used as a tool when grazing different species on the same pastures. The aim of this study was to estimate the effect of mixed grazing with cattle on the development of GIN infections in goats. Goat flocks with 3 heifers (Group Mix; Visp: n = 12, Chur: n = 15) and without heifers (Group Solo; Visp: n = 7, Chur: n = 15) were grazed separately on pastures at altitudes of 910 m (location Chur) and 1240 m (location Visp) above sea level resp. during one grazing season each. The composition of the mixed groups aimed to achieve a similar intake of roughage of both species. The stocking rate and the availability of roughage in the solo groups was balanced proportionately according to the situation in the mixed groups. The individual GIN egg excretion, the composition of the GIN larvae in the faeces, the FAMACHA©-Score and the pasture contamination with infective GIN larvae was determined in monthly intervals. At both sites the goats in the mixed groups showed a significantly lower mean GIN egg excretion compared with those of the Solo groups (p .Die zunehmende Resistenz der Magen-Darm-Strongy­liden (MDS) kleiner Wiederkäuer gegenüber Anthelminthika erfordert eine Diversifikation der Kontrollstrategien mit dem Ziel, deren einseitige Abhängigkeit von chemischen Wirkstoffen zu reduzieren. Dabei kann auch die Wirtstier-spezifische Entwicklung der MDS genutzt werden, indem verschiedene Tierarten die gleichen Futterflächen beweiden. Das Ziel dieser Studie war die Quantifizierung der Wirkung eines gemischten Weidesystems gegenüber MDS bei Ziegen durch die Einbeziehung von Rindern. Auf Höhenlagen von 910 m ü. M (Versuch Chur) und 1240 m ü. M (Versuch Visp) wurden während jeweils einer Weideperiode Ziegen allein (Gruppe Solo; Visp: n = 7, Chur: n = 15) sowie in einer gemischten Gruppe mit jeweils 3 Rindern (Gruppe Mix; Visp: n = 12, Chur: n = 15) geweidet und monatlich untersucht. Die Zusammensetzung der gemischten Gruppen erfolgte in der Weise, dass beide Tierarten etwa den gleichen Raufutterverzehr aufwiesen. Der Tierbesatz und das Futterangebot in den Solo-Gruppen entsprachen anteilsmässig dem der Ziegen in den gemischten Gruppen. Die individuelle Eiausscheidung von MDS sowie die im Kot der Tiere präsenten MDS-Gattungen, der Anämiegrad (FAMACHA©-Score) und die Weidekontamination mit infektiösen MDS-Larven wurden in etwa monatlichen Intervallen untersucht. An beiden Versuchsorten zeigten die Gruppen Mix eine signifikant tiefere MDS-Eiausscheidung (p .En raison de la résistance généralisée des nématodes gastro-intestinaux (NGI) des petits ruminants aux médicaments anthelminthiques, les stratégies de contrôle établies doivent être adaptées, visant à réduire leur forte dépendance aux substances chimiques. Le développement des NGI spécifiques à leur hôte peut être exploité, en introduisant la présence de différentes espèces d’hôtes sur les mêmes pâturages. Le but de cette étude était d’estimer l’effet du pâturage mixte avec des bovins sur le développement d’infections à NGI chez les chèvres. Des troupeaux de chèvres avec 3 génisses (Groupe Mix : Viège : n = 12, Coire : n = 15) et sans génisses (Groupe Solo : Viège : n = 7, Coire : n = 15) ont été placés sur des pâturages à des altitudes de 910 m (Coire) et 1240 m (Viège) au-dessus du niveau de la mer pendant une saison de pâturage. La composition des groupes mixtes visait à obtenir une consommation similaire de fourrage des deux espèces. La densité animale et la disponibilité du fourrage dans les groupes solos étaient en proportion comparables aux groupes mixtes. L’excrétion individuelle d’oeufs de NGI, les variétés de genres de NGI dans les fèces, le taux d’anémie (score FAMACHA©) et la contamination des pâturages par des larves infectieuses de NGI ont été déterminés à intervalles mensuels. Sur les deux sites, les chèvres des groupes Mix ont montré une excrétion d’oeufs de NGI significativement inférieure par rapport à celle des groupes Solo (p .Alfine di ridurre la dipendenza dai vermifugi è necessaria una diversificazione delle strategie di controllo in modo da ridurre la crescente resistenza agli antielmintici negli strongili gastrointestinali (SGI) nei piccoli ruminanti. Lo sviluppo specifico degli SGI a dipendenza dell’animale ospite può anche essere sfruttata permettendo a diverse specie animali di utilizzare le stesse aree di pascolo. Lo scopo di questo studio era di quantificare l’effetto di un sistema di pascolo misto con bovini sulla presenza degli SGI nelle capre. A un’altitudine di 910 m (sito Coira) e 1240 m s. l. m. (sito Visp) un gruppo di capre fu lasciato a pascolare da solo (gruppo Solo; Visp: n = 7, Coira: n = 15) oppure in un gruppo misto di capre con 3 bovini (gruppo Mix; Visp: n = 12, Coira: n = 15) durante una stagione di pascolo. La composizione dei gruppi misti era tale da permettere a entrambe le specie un consumo simile di foraggio grezzo. L’occupazione dei pascoli e l’offerta di foraggio dei gruppi Solo corrispondeva proporzionalmente a quella delle capre nei gruppi Mix. L’escrezione individuale di uova di SGI così come i generi di SGI presenti nelle feci degli animali, il grado di anemia (punteggio FAMACHA©) e la contaminazione del pascolo con larve infettive di SGI furono esaminati a intervalli mensili. In entrambi i siti le capre dei gruppi Mix mostrarono un’escrezione media di uova di SGI significativamente inferiore (p .

Resistance to benzimidazoles (BZs) in trichostrongyloid nematodes is a worldwide problem for livestock production, particularly regarding small ruminants. Sensitive and reliable methods are required to assess anthelmintic resistance status. Currently available methods for BZ resistance detection can be divided into three main groups, in vivo (e.g. faecal egg count reduction test), in vitro (e.g. egg hatch assay) and molecular tests. Three single nucleotide polymorphisms (SNPs) in the isotype-1 β-tubulin gene of various nematode species correlate with BZ resistance. While PCR-based methods have been reported for the three most economically important nematodes of sheep, namely, Trichostrongylus, Haemonchus and Teladorsagia, pyrosequencing assays are so far only available for the latter two. Here, the design and evaluation of pyrosequencing assays for isotype-1 and isotype-2 β-tubulin genes of Trichostrongylus colubriformis are described. PCR fragments carrying the susceptible and corresponding resistant genotype were combined in defined ratios to evaluate assay sensitivity and linearity. The correlation between the given and the measured allele frequencies of the respective SNPs (codons F167Y, E198A and F200Y) was very high. Pyrosequencing assays for Haemonchus, Teladorsagia and Trichostrongylus were subsequently used for a BZ resistance survey, carried out in the three European countries, namely Ireland, Italy and Switzerland. Larval cultures obtained from field survey samples in 2012 and 2013 were used for pyrosequencing. The test was applied when the target species represented at least 10% of the sample. Trichostrongylus and Teladorsagia were detected in all countries' samples whereas Haemonchus was not detected in samples from Ireland. SNPs in isotype-1 associated with resistance were detected for all three species, with frequencies at codon F200Y far exceeding those at codons F167Y and E198A. Elevated SNP frequencies in isotype-2 of Trichostrongylus were only rarely detected. Farms with BZ resistance-associated SNP frequencies above 10% were most often found in Switzerland followed by Ireland and Italy., Graphical abstract Image 1, Highlights • Successful development of a pyrosequencing assay for Trichostrongylus. • Resistance survey revealed high number of SNPs present in all three countries. • SNP at codon 200 most prevalent in European trichostrongyloid populations. • Low number of SNPs found in Italy corresponds to FECRT data. • Pyrosequencing successfully employed as a tool for large scale surveys.

Forty goats, aged from 2 to 5 months were subjected to two different immunization protocols with a vaccine containing Haemonchus contortus gut membrane proteins H11/H-gal-GP to evaluate protection against H. contortus on pre-contaminated pastures. Goats were allocated to four groups of ten, three of them received their first vaccination before turnout. One group (V4) was then vaccinated at 4-week-intervals whereas another two groups (V6 and V6SEP) were vaccinated at 6-week-intervals. A control group (CTRL) remained unvaccinated. In May, after the second vaccination, all goats were turned out on pastures which had been previously contaminated with H. contortus eggs by seeder sheep for a period of six weeks. Goats of groups V4, V6 and CTRL were grazed together, whereas V6SEP was kept separately at an identical stocking rate. Clinical (PCV, FAMACHA, body weight), parasitological (faecal egg count, FEC) and serological (antibody titres) parameters were measured fortnightly. All goats were stabled in October, drenched with levamisole and two weeks later infected with 5000 L3 of H. contortus and slaughtered four weeks later for determination of abomasal worm burdens. Group mean FEC peaked 42–56 days after turnout. Significantly lower FEC were observed in V6SEP vs CTRL between D 28 and 70 (p < 0.01). Mean egg output of all groups decreased substantially and fluctuated at low levels until the end of the grazing period (D 154). Goats responded to vaccination with increasing antibody titres peaking after every booster. Mean worm burdens deriving from experimental infections were reduced by 89, 65 and 47% in groups V4, V6 and V6SEP, respectively, compared with the controls. The difference was significant for V4 (p < 0.01). Antibody titres measured 14 days before slaughter did not correlate statistically with the worm burdens. It was concluded that the vaccination protocol did not result in sufficient protection on pasture, as antibody titres were still low at the time the goats were exposed to larval contamination on pasture after turnout.

The aim of the study was to get an overview of control measures against gastrointestinal nematodes in goats in Switzerland. Based on the answers to a questionnaire, we assessed the readiness of owners to use targeted or targeted selective treatment, and to develop a practical decision tool for the indication of treatment of individual animals. The results show that the number of treatments per year decreased compared to previous studies. Furthermore, the survey shows that a large proportion of goat farmers (73.9%) is willing to change the present treatment strategy. A simple decision key based on the evaluation of body condition, the consistency of the faeces and the degree of the anaemia (FAMACHA©) was tested in a field survey. It could be shown that goat owners are able to carry out the simple protocol reliably on their own and correctly evaluate individuals regarding their need of treatment.Das Ziel der vorliegenden Arbeit war es, auf der Basis einer Umfrage einen Überblick über die Kontrolle gastrointestinaler Nematoden bei Ziegen in der Schweiz zu erhalten, die Bereitschaft der Tierhalter zur Durchführung von gezielten Entwurmungen abzuschätzen und eine praxisnahe Methode zur Ermittlung des Behandlungsbedarfs bei Einzeltieren zu entwickeln. Die Ergebnisse zeigen, dass die Anzahl anthelminthischer Therapien pro Jahr gegenüber älteren Studien reduziert werden konnte. Ein grosser Anteil der Ziegenhalter (73.9%) ist bereit, ihr gegenwärtiges Entwurmungsregime umzustellen. Ein Entscheidungsschlüssel, bestehend aus der Beurteilung des Nährzustands, der Kotkonsistenz sowie des Anämiegrades (FAMACHA©) wurde in einem Feldversuch geprüft. Die Tierhalter waren nach einer Schulung in der Lage, das Protokoll selbstständig und zuverlässig anzuwenden und die Tiere bezüglich ihres Behandlungsbedarfs korrekt zu bewerten.Le but du présent travail était, sur la base d’une enquête, d’obtenir une vision d’ensemble du contrôle des nématodes gastro-intestinaux chez les chèvres en Suisse, d’estimer la disposition des éleveurs pour effectuer des traitements ciblés et de développer une méthode permettant de mesurer la nécessité d’un traitement individuel des animaux. Les résultats montrent que, par rapport à d’anciennes études, le nombre annuel de traitements anthelminthiques pourrait être réduit. Un grand nombre de propriétaires de chèvres (73.9%) sont prêts à modifier leur régime actuel de vermifugation. Une clé de décision, comprenant une estimation de l’état d’embonpoint, de la consistance des selles ainsi que du degré d’anémie (FAMACHA©) a été testée en pratique. Les détenteurs étaient à même, après une formation, de remplir seuls et de façon fiable le protocole et d’estimer ainsi correctement le besoin de traitement de leurs animaux.Scopo di questo studio è di ottenere, sulla base di un sondaggio, una vista d’insieme sul controllo dei nematodi gastrointestinali nei caprini in Svizzera, di valutare la volontà degli allevatori di somministrare dei vermifughi mirati e di sviluppare una metodologia pratica per determinare la necessità di trattamento di ogni animale. I risultati hanno evidenziato, al contrario degli studi precedenti, che il numero annuale di terapie antielmintiche potrebbero essere ridotte. Una gran parte dei detentori di caprini (73.9%) è disponibile ad adattare il sistema attuale di vermifughi. Una metodologia decisionale comprendente la valutazione dello stato di alimentazione, la consistenza delle feci e il grado di anemia (FAMACHA©) è stata testata sul campo. I detentori degli animali erano, dopo un corso di formazione, in grado applicare il protocollo in modo indipendente e affidabile e di valutare gli animali in termini di necessità di un trattamento corretto.

Pursuant to the Joint Declaration by 29 European education ministers in June 1999 in the city of Bologna, Italy, the so-called 'Bologna Process' was officially introduced at the Vetsuisse Faculty (Universities of Zurich and Berne) in Switzerland in 2007. The long-term goal of restructuring the study programmes was to create a common European Higher Education Area (EHEA), with uniform and clearly defined standards for degrees ("diplomas"). Accordingly, the Vetsuisse curriculum was organised as a 3-year Bachelor and a 2-year Master study program. For the final Federal examination in veterinary medicine, both programs and a master thesis have to be completed. Parasitology, as a subject, is introduced with selected examples in the ecology course during the first academic year. The second and third years of the Bachelor program comprise non-organ-centred (NOC) and integrated organ-centred (OC) course modules, respectively. In the NOC modules, parasitology is taught in consecutive courses, focussing on topics including occurrence, biology, pathogenesis, clinical manifestations, diagnostics and the strategic principles of therapeutic and prophylactic interventions against major veterinary and zoonotic parasites. This syllabus is complemented with live demonstrations as well as practical laboratory exercises. Lecture notes, with defined learning objectives, are based on the textbook "Parasitology in Veterinary Medicine" which is available free of charge to students as an on-line edition in German. Furthermore, students review relevant parasitoses in the diagnostic context of OC case presentations. In another module, immunological aspects of parasitic diseases are elaborated on group sessions, supported through the use of specialist literature. The two-year Master program is divided into a core syllabus for all students, and elective subjects are chosen from six areas of specialisation (three each with clinical or non-clinical focus). Within the clinically focused specialisations, interactive teaching of control strategies against parasitoses of companion and farm animals is the focus. Students specialising in 'Pathobiology' experience a deep immersion in parasitology. Learning objectives are verified in different test formats. E-learning tools, including a learning management on-line platform, allow interactive student training in coproscopic diagnostic techniques and in arachno-entomology and provide case-oriented teaching. Since an aptitude test limits the number of first-year students in veterinary medicine in Switzerland (80 in Zürich, 70 in Berne), the conditions for students and teachers are similar each year. The fragmentation of teaching in veterinary parasitology, the reduction of the number of diagnostic exercises and clinically oriented day-1-skills pertaining to the control of parasitoses are critically commented upon.

A field study was undertaken on three Swiss sheep farms (A, B, C) to evaluate the efficacy of a long-acting moxidectin formulation (Cydectin® 2% LA) against gastrointestinal nematodes (GIN). Naturally infected ewes (all three farms) and their winter-borne lambs (farms A and B) were allocated to two groups (MOX, CON). At day 0 ewes of the MOX-groups were treated with 1 mg moxidectin s.c. CON- and MOX-groups were grazed on separate pastures and were sampled for faeces and blood at 28-day intervals. Larval cultures demonstrated that Haemonchus contortus was the dominant GIN-species in ewes throughout the season. Over the entire observation period faecal egg count (FEC) of the MOX-ewes in farms A, B, C was 56%, 84% and 87% less than the CON-ewes (p

The epidemiological situation of strongyle infections in adult horses in Switzerland is characterized by a strong dominance of small strongyles (Cyathostominae) and an overall low level of egg shedding in the faeces. The prevailing attitude towards anthelmintic therapy considers neither husbandry conditions nor pasture hygiene measures. Instead, calendar-based routine medication, comprising usually 3 to 4 annual treatments, is the typical strategy. Such an approach, however, often results in an excessive administration of anthelmintics. With respect to the continuous spread of drug resistant cyathostomins a change of strategy seems inevitable. A consensus has been agreed on between equine parasitologists and clinicians of the Vetsuisse Faculty in Zurich and Berne to focus on the concept of a selective control approach, based on individual faecal egg counts as the central element. It is now recommended that clinically healthy horses (> 4 y) are treated only when their strongyle egg count is equal to or higher than 200 eggs per gram of faeces. A regular analysis of the strongyle population based on larval cultures, the control of drug efficacy, and quarantine measures for incoming horses are mandatory components of the concept. Recent experiences in several pilot farms have indicated that only 4 % of the McMaster analyses resulted in a deworming treatment. For horses that did not receive any nematicidal anthelmintic during the current season, a "safety" treatment is recommended at the end of the grazing period., Die epidemiologische Situation der Strongyliden-Infektionen beim adulten Pferd in der Schweiz ist geprägt von einer starken Dominanz kleiner Strongyliden (Cyathostominae) und einem mehrheitlich geringen Ausscheidungsniveau von Parasiteneiern im Kot. Da die Haltungsbedingungen der Pferde und weidehygienische Massnahmen bei der Planung der Kontrollmassnahmen mehrheitlich unberücksichtigt bleiben, resultiert die kalenderbasierte Routine-Medikation mit 3 bis 4 Behandlungen pro Jahr häufig in einem über dem Bedarf liegenden Einsatz von Anthelminthika. Angesichts der sich kontinuierlich ausbreitenden Populationen Anthelminthika-resistenter Cyathostominen ist ein Strategiewechsel bei der Helminthenkontrolle notwendig. Bei dem von Parasitologen und Klinikern beider Vetsuisse-Standorte propagierten selektiven Kontrollansatz werden klinisch gesunde Pferde (> 4 Jahre) nur noch dann anthelminthisch behandelt, wenn die Ausscheidung von Strongylideneiern einen Wert von 200 pro Gramm Kot überschreitet. Eine regelmässige Differenzierung der Strongylidenpopulation, Wirksamkeitskontrollen der Anthelminthika und Quarantänemassnahmen bei Neuzugängen sind notwendige Komponenten des Konzeptes. Bisherige Erfahrungen mit dieser Strategie in mehreren Pilotbetrieben zeigen, dass nur 4 % der Kotuntersuchungen einen Anthelminthika-Einsatz zur Folge haben. Für die Pferde, die während der Saison kein Anthelminthikum erhielten, wird eine Sicherheitsbehandlung zum Saisonende empfohlen.

Management of paddocks for free-range layers requires an effort from farmers to minimize the adverse effects of these systems on animal health (e.g., parasites) and environment (e.g., nutrient accumulation and leaching). In this study, we report results from 2 on-farm experiments conducted to investigate (1) the effects of rotational versus continuous use of the paddocks and (2) the effects of wood chips in the area close to the pop holes (openings to the paddock) with regard to turf quality, nutrient load in the soil, and parasite infections. Rotational use of the hen paddocks led to a lower proportion of bare soil close to the house, but not in more distant regions. Covering the area in front of the house with wood chips did not reduce bare areas. Nitrogen and phosphorous contents in soil were similar in permanently and rotationally used paddocks; they were usually higher close to the house than in distant regions. Neither nutrient accumulated over the observation period. There was no significant effect of the 2 management regimens on worm burdens (Ascaridia galli, Heterakis gallinarum, Capillaria spp.) at the end of the laying period. Fecal egg counts were significantly reduced on rotationally used paddocks and (in 3 of 4 cases) on paddocks with wood chips in the area close to the pop holes compared with unmanaged paddocks. Based on the positive effects on turf quality, manageability, and helminth egg excretion, we recommend rotational paddock management and a permanently used, small all-weather run covered with wood chips or gravel for free-range layer flocks

Research in ruminant nutrition and helminth control with forages, which contain condensed tannins (CT), suggests that varying responses may depend not only on CT concentration but also on CT composition. An experiment was designed to test this by feeding 2 dried sainfoin cultivars (Visnovsky and Perly), which differed in CT properties, to lambs that were artificially infected with the abomasal blood-sucking nematode Haemonchus contortus. Twenty-four infected lambs received 1 of these 2 cultivars; the feeds were either untreated or treated with the CT-binding polyethylene glycol over 4 wk (n = 6). The 2 cultivars were also fed to 2 × 6 uninfected lambs. Nutrient digestibility, N balance, ADG, plasma urea, together with indicators of infection [fecal egg count (FEC), abomasal worm count, per capita female fecundity, erythrocytic indices, and serum protein], were determined. The specific effects of sainfoin cultivar, CT, and infection were evaluated by contrast analysis. Digestibility of both NDF and ADF were less (P < 0.001) with Perly compared with Visnovsky. The apparent nutrient digestibility was reduced (P < 0.001) by CT. However, no clear cultivar effects were evident on N excretion and retention. Condensed tannins reduced (P = 0.05) body N retention and shifted (P < 0.001) N excretion from urine to feces. Unlike cultivar and CT, infection decreased (P = 0.002) ADG. Plasma urea concentration was decreased (P = 0.007) in Perly- compared with Visnovsky-fed lambs and was decreased (P < 0.001) by CT. Plasma concentrations of essential and semiessential AA were increased (P < 0.001) by CT. The groups of infected lambs did not clearly differ in abomasal worm counts and erythrocytic indicators. In the last 2 to 3 wk of the experiment, FEC was decreased (P ≤ 0.01) when feeding CT. The lack of substantial cultivar effects suggests that the differences in CT properties may have been too small to result in nutritional and anthelmintic effects. The present results indicate that sainfoin CT had a mitigating effect on FEC and, consequently, pasture infectivity. However, the reduction was too small to expect any significant benefits in an Haemonchus-dominated system. Therefore, the use of sainfoin for controlling H. contortus should only be one component within an integrated worm control system.

Infections with parasitic helminths (nematodes and trematodes) represent a significant economic and welfare burden to the global ruminant livestock industry. The increasing prevalence of anthelmintic resistance means that current control programmes are costly and unsustainable in the long term. Recent changes in the epidemiology, seasonality and geographic distribution of helminth infections have been attributed to climate change. However, other changes in environment (e.g., land use) and in livestock farming, such as intensification and altered management practices, will also have an impact on helminth infections. Sustainable control of helminth infections in a changing world requires detailed knowledge of these interactions. In particular, there is a need to devise new, sustainable strategies for the effective control of ruminant helminthoses in the face of global change. In this paper, we consider the impact of helminth infections in grazing ruminants, taking a European perspective, and identify scientific and applied priorities to mitigate these impacts. These include the development and deployment of efficient, high- throughput diagnostic tests to support targeted intervention, modelling of geographic and seasonal trends in infection, more thorough economic data and analysis of the impact of helminth infections and greater translation and involvement of end-users in devising and disseminating best practices. Complex changes in helminth epidemiology will require innovative solutions. By developing and using new technologies and models, the use of anthelmintics can be optimised to limit the development and spread of drug resistance and to reduce the overall economic impact of helminth infections. This will be essential to the continued productivity and profitability of livestock farming in Europe and its contribution to regional and global food security. View Full-Text

Im Jahr 2011 wurde von den Pferdeklinikern und Parasitologen der beiden veterinarmedizinischen Bildungsstatten Bern und Zurich eine Neuorientierung des Entwurmungsmanagements fur Pferde vorgeschlagen. Die Hauptziele dieser Initiative liegen in einem bedarfsgerechten Anthelminthika-Einsatz beim erwachsenen Pferd und einer damit verbundenen Eindammung der Resistenzproblematik. Die schweizerischen Erfahrungen mit diesem selektiven Behandlungskonzept und Resultate aus dem Parasiten-Monitoring in Pferdebestanden werden in diesem Beitrag vorgestellt.

The impact of climate change on parasites and parasitic diseases is a growing concern and numerous empirical and mechanistic models have been developed to predict climate-driven spatial and temporal changes in the distribution of parasites and disease risk. Variation in parasite phenotype and life-history traits between isolates could undermine the application of such models at broad spatial scales. Seasonal variation in the transmission of the haematophagous gastrointestinal nematode Haemonchus contortus, one of the most pathogenic helminth species infecting sheep and goats worldwide, is primarily determined by the impact of environmental conditions on the free-living stages. To evaluate variability in the development success and mortality of the free-living stages of H. contortus and the impact of this variability on future climate impact modelling, three isolates of diverse origin were cultured at a range of temperatures between 15 °C and 37 °C to determine their development success compared with simulations using the GLOWORM-FL H. contortus model. No significant difference was observed in the developmental success of the three isolates of H. contortus tested, nor between isolates and model simulations. However, development success of all isolates at 37 °C was lower than predicted by the model, suggesting the potential for overestimation of transmission risk at higher temperatures, such as those predicted under some scenarios of climate change. Recommendations are made for future climate impact modelling of gastrointestinal nematodes.

Summary Background When chromatin diminution occurs during a cell division a portion of the chromatin is eliminated, resulting in daughter cells with a smaller amount of genetic material. In the parasitic roundworms Ascaris and Parascaris , chromatin diminution creates a genetic difference between the soma and the germline. However, the function of chromatin diminution remains a mystery, because the vast majority of the eliminated DNA is noncoding. Within the parasitic roundworm genus Strongyloides , S. stercoralis (in man) and S. ratti (in rat) employ XX/XO sex determination, but the situation in S. papillosus (in sheep) is different but controversial. Results We demonstrate genetically that S. papillosus employs sex-specific chromatin diminution to eliminate an internal portion of one of the two homologs of one chromosome pair in males. Contrary to ascarids, the eliminated DNA in S. papillosus contains a large number of genes. We demonstrate that the region undergoing diminution is homologous to the X chromosome of the closely related S. ratti . The flanking regions, which are not diminished, are homologous to the S. ratti autosome number I. Furthermore, we found that the diminished chromosome is not incorporated into sperm, resulting in a male-specific transmission ratio distortion. Conclusions Our data indicate that on the evolutionary path to S. papillosus , the X chromosome fused with an autosome. Chromatin diminution serves to functionally restore an XX/XO sex-determining system. A consequence of the fusion and the process that copes with it is a transmission ratio distortion in males for certain loci.

Tanniferous temperate legumes are assumed to possess anthelmintic properties, but it is unclear whether this is the direct result of condensed tannins (CT) or is mediated indirectly via an improved metabolic protein supply. A metabolism experiment was conducted to differentiate between these factors by feeding the CT plant sainfoin (19.7% CP in DM) to lambs infected with the abomasal blood-sucking nematode Hemonchus contortus. A total of 18 infected lambs were fed sainfoin either untreated or treated with polyethylene glycol, a CT-inactivating agent, or a grass-clover mixture (13.2% CP in DM) over 3 wk (n = 6). Six uninfected lambs received the grass-clover mixture as a control. In addition to indicators of infection (fecal egg count, packed-cell volume, abomasal worm burden, and serum protein), nutrient digestibility, the balance of N and selected minerals, ruminal fluid characteristics, and plasma AA levels were determined mostly in the final experimental week. The specific effects of the sainfoin CT, the extra CP with sainfoin, and the infection were statistically evaluated by contrast analysis. The sainfoin CT exerted no beneficial effects on resilience to nematode infection and exerted only minor effects on ruminal ammonia or blood urea concentrations and the excretory pattern of N. Plasma alanine, aspartate, and proline concentrations tended to be greater (P < or = 0.09) because of the sainfoin CT, whereas the other AA remained unaffected. Intake of the mineral supplement was lower (P < 0.001) for lambs fed sainfoin compared with those fed sainfoin treated with polyethylene glycol. Feeding the high-protein sainfoin instead of the grass-clover mixture increased (P < 0.001) N retention and apparent OM digestibility, whereas digestibility of NDF and ADF were decreased (P < 0.001). Feeding sainfoin also decreased (P < or = 0.04) plasma alanine, glycine, isoleucine, and total nonessential AA compared with the grass-clover mixture. Although fecal egg count, worm burden, and packed cell volume were not affected by the greater CP supply associated with sainfoin feeding, serum albumin level was increased (P = 0.008). The lack of effects of sainfoin on resilience to nematode infection might have been the result of the unexpectedly low CT content (3.6% in DM) of the material used. It cannot be excluded that longer term feeding of this batch of sainfoin might have been effective.

SUMMARYTaenia saginatacysticercosis causes financial losses to the beef industry and farmers, and represents a significant source for human infection in many countries. A case-control study was conducted to identify risk factors for bovine cysticercosis on farms in Switzerland. The case group (n=119) consisted of farms with infected cattle identified at slaughter in 2005 and 2006. Infections were confirmed by morphological or molecular diagnosis. The control group (n=66) comprised randomly selected farms with cattle slaughtered in the same period but with no evidence or history of infection. In personal structured interviews with the farmers, information regarding local surroundings and farm management was collected. Logistic regression revealed the following 5 factors as being positively associated with the occurrence of bovine cysticercosis: the presence of a railway line or a car park close to areas grazed by cattle, leisure activities around these areas, use of purchased roughage and organized public activities on farms attracting visitors. This information is considered useful for government authorities to direct control strategies as well as for farmers to take measures tailored to local situations.

A field study was conducted on three Swiss farms to investigate the efficacy of Duddingtonia flagrans against naturally acquired infections of gastrointestinal nematodes in adult dairy sheep. On each farm the ewes were divided into two equal groups. One group received Duddingtonia during a period of 4 months at a daily dose rate of 106 chlamydospores per kilogram body weight, the second group acted as controls. At an overall moderate infection level in all farms D. flagrans did not have a significant effect on the observed parasitological parameters with the exception of a significantly reduced herbage infectivity in one farm. In contrast, the results from faecal cultures indicated a mean suppression of larval development during the fungus-feeding period between 82, 89 and 93% on the three farms, respectively. The discrepancy observed between the fungus efficacy in coprocultures and on pasture, which was also observed in several other studies deserves further research.

We investigated direct anthelmintic effects associated with the feeding of fresh tanniferous forages against established populations of Haemonchus contortus and Cooperia curticei in lambs. Twenty-four parasite naive lambs were inoculated with a single dose of infective larvae of these two parasites 27 days prior to the start of the feeding experiment. Lambs were individually fed with either chicory (Cichorium intybus), birdsfoot trefoil (Lotus corniculatus), sainfoin (Onobrychis viciifolia) or a ryegrass/lucerne mixture (control) for 17 days. Animals where then united to one flock and subjected to control feeding for another 11 days to test the sustainability of potentially lowered egg excretion generated by tanniferous forage feeding. When compared to the control, administration of all tanniferous forages was associated with significant reductions of total daily faecal egg output specific to H. contortus (chicory: 89%; birdsfoot trefoil: 63%; sainfoin: 63%; all tests P0.05) and a tendency of reduced H. contortus worm burden (chicory: 15%; birdsfoot trefoil: 49% and sainfoin: 35% reduction). Irrespective of the condensed tannin (CT) containing fodder, no anthelmintic effects were found against C. curticei. Cessation of CT-feeding followed by non-CT control feeding did not result in a re-emergence of faecal egg counts based on faecal dry matter (FECDM) in any group, suggesting that egg output reductions are sustainable. The moderate to high concentrations of CTs in birdsfoot trefoil (15.2 g CTs kg(-1) dry matter (DM)) and sainfoin (26.1 g CTs kg(-1) DM) were compatible with the hypothesis that the antiparasitic effect of these forages is caused by their content of CTs. For chicory (3 g CTs kg(-1) DM), however, other secondary metabolites need to be considered. Overall, birdsfoot trefoil and in particular sainfoin seem promising candidates in contributing to an integrated control strategy against H. contortus not only by mitigating parasite related health disturbances of the host but also by a sustained reduction of pasture contamination.

Anthelmintic resistance in gastrointestinal nematodes among small ruminants is widespread in South Africa and Dorper sheep and Boer goats have been imported into Switzerland from this country on a number of occasions. Therefore, this study aimed to investigate the occurrence of avermectin (AVM) resistant gastrointestinal nematodes (GIN) in these breeds in Switzerland. A total of 24 Boer goat farms and 12 Dorper sheep farms participated in the study. According to the faecal egg count reduction test (FECRT) AVM-resistant GIN populations were confirmed in 7 of the 24 Boer goat farms and suspected in a further 8 farms. Likewise AVM-resistance was confirmed in 2 of 12 Dorper sheep farms and suspected in a further 6 farms. Haemonchus contortus and Trichostrongylus spp. were the dominant resistant species according to larval cultures. In the farms with detected AVM-resistance the animals were additionally treated with levamisole after natural reinfection. With the exception of one farm with a 'close-to cutoff-result' the FECRT gave no indication for resistance against levamisole. The results indicate that AVM-resistance is widespread in Swiss small ruminant farms keeping Boer goats and Dorper sheep. The common tradition of grazing animals from different farms on prealpine and alpine pastures could favour the spread of resistant populations within the country.

Anthelmintic resistance (AR) in gastrointestinal nematodes (GINs) has been reported worldwide in multiple nematode and livestock species (Kaplan and Vidyashankar 2012) and is a major constraint on production on affected farms (Sutherland and others 2010, Miller and others 2012). In the UK and Ireland, for example, AR in GINs and anthelmintic treatment failure is widespread in sheep (e.g. Bartley and others 2003, Keane and others 2014) and increasingly reported in cattle (e.g. O'Shaughnessy and others 2014). There is, therefore, a need to develop and adopt GIN control strategies that maintain the efficacy of anthelmintics and to identify risk factors for the development of AR. Environmental constraints on farm management and the survival of nematodes in refugia appear to play an important role in the development of AR. In a random survey of sheep farms in Norway, AR was found only in coastal regions (Domke and others 2012a). Papadopoulos and others (2001) observed a higher incidence of AR on isolated Greek islands, suggesting that drought hastens the development of AR. In contrast, Rinaldi and others (2014) observed high anthelmintic efficacy in sheep in southern Italy despite the Mediterranean climate. This was attributed to the low number of anthelmintic treatments (usually two per year) and the absence of anthelmintic treatments during periods of drought, when environmental constraints on the free-living stages are highest. Calvete and others (2012) identified an association between AR, distance between farms with AR, management and bioclimatic …

Haemonchus contortus is a species of gastrointestinal strongyles of primary concern for sheep. This highly pathogenic, blood-feeding helminth negatively influences animal health, welfare and productivity. In order to elucidate the current scenario in terms of prevalence and intensity of H. contortus infection in sheep farms across Europe, a standardized crosssectional survey was conducted in three pilot areas in Ireland, Switzerland and Italy, all part of the EU funded GLOWORM project. Two consecutive field surveys (in 2012 and 2013) were conducted in the three countries in the same period (August-October) in 259 sheep farms in total. Harmonized, diagnostic procedures (from farm to laboratory) based on pooled samples, the FLOTAC technique and coproculture were used. The georeferenced parasitological results were modelled (at the pilot area level) following a Bayesian geostatistical approach with correction for preferential sampling and accounting for climatic and environmental covariates. The observed H. contortus prevalence rates did vary between the countries showing high values in Switzerland (77%) and Italy (73%) compared to Ireland (4%). Spatial patterns of H. contortus distribution were detected in Switzerland and Italy with a north-south gradient. The latent factor analysis highlighted the importance of seasonality and annual cyclicity within country (particularly in southern Italy), while mean temperature and rainfall dominated between country variations in the prevalence of H. contortus infection.

Background Lectins are carbohydrate-binding proteins that are involved in fundamental intra- and extracellular biological processes. They occur ubiquitously in nature and are especially abundant in plants and fungi. It has been well established that certain higher fungi produce lectins in their fruiting bodies and/or sclerotia as a part of their natural resistance against free-living fungivorous nematodes and other pests. Despite relatively high diversity of the glycan structures in nature, many of the glycans targeted by fungal lectins are conserved among organisms of the same taxon and sometimes even among different taxa. Such conservation of glycans between free-living and parasitic nematodes is providing us with a useful tool for discovery of novel chemotherapeutic and vaccine targets. In our study, a subset of fungal lectins emanating from toxicity screens on Caenorhabditis elegans was tested for their potential to inhibit larval development of Haemonchus contortus. Methods The effect of Coprinopsis cinerea lectins - CCL2, CGL2, CGL3; Aleuria aurantia lectin – AAL; Marasmius oreades agglutinin - MOA; and Laccaria bicolor lectin – Lb-Tec2, on cultivated Haemonchus contortus larval stages was investigated using a larval development test (LDT). To validate the results of the toxicity assay and determine lectin binding capacity to the nematode digestive tract, biotinylated versions of lectins were fed to pre-infective larval stages of H. contortus and visualized by fluorescent microscopy. Lectin histochemistry on fixed adult worms was performed to investigate the presence and localisation of lectin binding sites in the disease-relevant developmental stage. Results Using an improved larval development test we found that four of the six tested lectins: AAL, CCL2, MOA and CGL2, exhibited a dose-dependent toxicity in LDT, as measured by the number of larvae developing to the L3 stage. In the case of AAL, CGL2 and MOA lectin, doses as low as 5 μg/ml caused >95 % inhibition of larval development while 40 μg/ml were needed to achieve the same inhibition by CCL2 lectin. MOA was the only lectin tested that caused larval death while other toxic lectins had larvistatic effect manifesting as L1 growth arrest. Using lectin histochemistry we demonstrate that of all lectins tested, only the four toxic ones displayed binding to the larvae’s gut and likewise were found to interact with glycans localized to the gastrodermal tissue of adults. Conclusion The results of our study suggest a correlation between the presence of target glycans of lectins in the digestive tract and the lectin-mediated toxicity in Haemonchus contortus. We demonstrate that binding to the structurally conserved glycan structures found in H. contortus gastrodermal tissue by the set of fungal lectins has detrimental effect on larval development. Some of these glycan structures might represent antigens which are not exposed to the host immune system (hidden antigens) and thus have a potential for vaccine or drug development. Nematotoxic fungal lectins prove to be a useful tool to identify such targets in parasitic nematodes., Parasites & Vectors, 8 (1), ISSN:1756-3305

Fasciola hepatica infection challenges health, welfare and productivity of small ruminants throughout the world. The distribution of F. hepatica in sheep in Europe is usually scattered and studies are generally concerned with a single area making it difficult to compare results from different environments, climates and management regimes. In order to elucidate the current scenario in terms of prevalence and intensity of F. hepatica infection in sheep farms across Europe, a standardized cross-sectional survey was conducted in three pilot areas in Ireland, Switzerland and Italy, all part of the EU funded GLOWORM project. Two consecutive field surveys (in 2012 and 2013) were conducted in the three countries in the same period (August-October) in 361 sheep farms in total. Harmonized procedures (from farm to laboratory) based on pooled samples and the highly sensitive and accurate, diagnostic FLOTAC technique were used. The georeferenced parasitological results were modelled (at the pilot area level) following a Bayesian geostatistical approach with correction for preferential sampling and accounting for climatic and environmental covariates. The observed F. hepatica prevalence rates did not differ between the two study years in any of the three pilot areas, but they did vary between the countries showing high values in Ireland (61.6%) compared to Italy (7.9%) and Switzerland (4.0%). Spatial patterns of F. hepatica distribution were detected by the Bayesian geostatistical approach in Ireland with a high risk of infection in the south-western part of the pilot area there. The latent factor analysis highlighted the importance of year-to-year variation of mean temperature, rainfall and seasonality within a country, while long-term trends of temperature and rainfall dominated between countries with respect to prevalence of infection.

Potent anthelmintics were introduced into the Swiss market several decades ago. Despite this, gastrointestinal nematodes (GIN), lungworms and the large liver fluke (Fasciola hepatica) can successfully inhabit Swiss ruminant farms. This is mainly due to a high reproductive capacity as well as very efficient survival strategies. In addition some species readily develop anthelmintic resistance. GIN-infections in young cattle are under comparatively good control. However, prophylactic measures are compromised where adult stock is also affected due to incomplete development of immune protection. Under these circumstances control measures must include all age groups. This results in fewer helminths in refugia thus may accelerate the development of anthelmintic resistance. This review aims to present a synopsis of the significance of the major helminth infections obtained on pasture by large and small ruminants in Switzerland. Currently available strategies for strategic helminth control are summarized and an outlook is given on new developments which might expand the spectrum of control measures relevant for veterinary practice in the future.

Anthelmintic resistance has become an increasing problem particularly to gastrointestinal tract nematodes and appropriate methods are required to detect this phenomenon so the correct action can be taken. This paper compares a number of mathematical techniques that are used to analyse data. The negative binomial distribution is a mathematical distribution used to model aggregated data and hence is suitable to model the intensity of parasite burden and the magnitude of the faecal egg counts. Maximum likelihood techniques are utilised to exploit this mathematical distribution to analyse the magnitude of the faecal egg count reduction and decline in the worm burden in response to anthelmintic treatment. Data from experimental groups of sheep described in the accompanying paper are used. In addition, simulated data sets of faecal egg counts were created using a random number generator following appropriate negative binomial distributions. The results demonstrate this statistical model can detect evidence of anthelmintic resistance with a faecal egg reduction test that otherwise might require a slaughter trial to demonstrate. In addition, the simulated data sets confirm that there is a significant probability of failure to detect low anthelmintic efficacy with commonly used mathematical techniques. Consequently, the use of maximum likelihood mathematical techniques with a negative binomial statistical model would aid in the early detection of anthelmintic resistance using faecal egg count reductions and result in a lower probability of inappropriately assigning an anthelmintic as effective.

A suspected case of multiple anthelmintic resistance on a farm in the canton of Zurich, Switzerland, into which South African Boer goats had previously been imported, was confirmed in a controlled test. Twenty sheep were allocated into one control group and three treatment groups to determine the efficacy of mebendazole, ivermectin and moxidectin applying the faecal egg count reduction test (FECRT). The sheep were slaughtered 1 week later and post-mortem worm counts were performed. Benzimidazole and ivermectin resistance were found in Haemonchus contortus with an efficacy of 55 and 61%, respectively. Moxidectin appeared to be effective when the data was analysed according to the recommended analytical techniques with an efficacy of 96%. This is the first description of resistance of gastrointestinal nematodes to one of the macrocyclic lactones in small ruminants in Switzerland. The results are discussed in relation to the importance of controlling livestock before importation.

Forty-eight helminth-free lambs were divided into eight groups (A-H) of six animals. Groups A-G were infected artificially with 10,000 third stage larvae of Haemonchus contortus and 20,000 third stage larvae of Trichostrongylus colubriformis, whereas group H remained uninfected. Thirty days post-infection the lambs were treated orally with a single dosage of one of the following products: group A with 3 mg/kg body weight (BW) of an aqueous ethanol extract (70%, v/v) of the seeds of Azadirachta indica A. Juss syn. Melia azedarach L. (Meliaceae); group B with 1 g/kg BW of a raw powder of the leaves of Ananas comosus (L.) Merr. (Bromeliaceae); group C with 0.3 mg/kg BW of an aqueous ethanol extract of a 1:1 mixture (g/g) of Vernonia anthelmintica (L.) Willd. (Asteraceae) seeds and Embelia ribes Burm (Myrsinaceae) fruits; group D with 183 mg/kg BW of an aqueous ethanol extract of the whole plants of Fumaria parviflora Lam. (Fumariaceae); group E with 28 mg/kg BW of an aqueous ethanol extract of the seeds of Caesalpinia crista L. (Caesalpiniaceae); group F with 25 mg/kg BW of pyrantel tartrate and group G with 50% ethanol. Group H remained untreated. Only the ethanol extract of F. parviflora caused a strong reduction of the faecal egg counts (100%) and a 78.2 and 88.8% reduction of adult H. contortus and T. colubriformis on day 13 post-treatment. The extract was as effective as the reference compound pyrantel tartrate. Therefore, the ethanol extract itself or single constituents of F. parviflora could be a promising alternative source of anthelmintic for the treatment of gastrointestinal trichostrongylids in small ruminants.

Stimuliert durch ein stetig wachsendes Konsumenteninteresse und finanzielle Anreize des Bundes, hat die biologische Landwirtschaft in der Schweiz in den zurückliegenden Jahren erheblich an Bedeutung gewonnen. Innerhalb der biologisch bewirtschafteten Fläche nimmt das direkt oder indirekt von Wiederkäuern genutzte Grünland den grössten Teil ein. Massgeblich bedingt durch die bedeutende Zunahme der biologischen Milchviehhaltung ist die Kontaktfläche zwischen der tierärztlichen Praxis und dem Biolandbau bereits stark gewachsen. Der Bio-Status eines Betriebes berührt die tierärztliche Praxis vor allen in den Bereichen Komplementärtherapie/Arzneimittelverabreichung und bei den sogenannten zootechnischen Massnahmen (Enthornen, Kupieren etc.). Eine wichtige Anforderung an die biologisch bewirtschafteten Betriebe besteht in der Auflage, für Behandlungen von Tieren bevorzugt komplementärmedizinische Präparate oder Verfahren einzusetzen, sofern erfahrungsgemäss eine therapeutische Wirkung auf die betreffende Tierart und die zu behandelnde Krankheit erwartet werden kann. Das Spektrum der auf Biobetrieben in Verantwortung des Tierarztes prinzipiell einsetzbaren registrierten Arzneimittel ist jedoch nicht eingeschränkt, wenn die Erkrankung auf dem komplementären Weg erfahrungsgemäss nicht kuriert werden kann. Die rein präventive Anwendung allopathischer Tierarzneimittel ist jedoch nicht zulässig. Weitere Besonderheiten in Zusammenhang mit dem Arzneimitteleinsatz auf Biobetrieben betreffen die einzuhaltenden Absetzfristen, die Dokumentation und die für eine Biovermarktung tolerierte Behandlungshäufigkeit. In Konfliktfällen ist der Gesundheit eines Tieres grundsätzlich Vorrang gegenüber seinem Bio-Status einzuräumen. Bei der Vorbereitung der in der Praxis tätigen Tierärzte auf die neue Situation sind derzeit noch deutliche Defizite zu verzeichnen, obwohl bei der Betreuung von Biobetrieben ein besonderer Aufgaben- und Verantwortungsbereich übernommen wird. Die Ausweitung des Tätigkeitsfeldes und die damit verbundene Erweiterung des komplementärmedizinischen Therapiespektrums kann für engagierte Praktiker zukünftig eine Herausforderung und Chance zugleich darstellen.

Due to the development of anthelmintic resistance, there have been calls for more sustainable nematode control practices. Two important concepts were introduced to study and promote the sustainable use of anthelmintics: targeted treatments (TT), where the whole flock/herd is treated based on knowledge of the risk, or parameters that quantify the severity of infection; and targeted selective treatments (TST), where only individual animals within the grazing group are treated. The aim of the TT and TST approaches is to effectively control nematode-induced production impacts while preserving anthelmintic efficacy by maintaining a pool of untreated parasites in refugia. Here, we provide an overview of recent studies that assess the use of TT/TST against gastrointestinal nematodes in ruminants and investigate the economic consequences, feasibility and knowledge gaps associated with TST. We conclude that TT/TST approaches are ready to be used and provide practical benefits today. However, a major shift in mentality will be required to make these approaches common practice in parasite control.

Eprinomectin (EPN) is a member of the avermectin class of compounds and the only anthelmintic registered for goats in Switzerland with a zero milk withdrawal period. The aim of the present study was to identify the actual efficacy of EPN in an area with a higher density of goat enterprises. Forty-three randomly chosen farms from canton Berne were investigated. At least eight goats were investigated on every farm. Conditions for inclusion in the study were the absence of anthelmintic treatment during the previous six weeks and a pooled faecal sample showing a mean faecal egg count (FEC) higher than 600 epg faeces. Pre- and 14-16 days post-treatment samples were individually collected directly from the rectum. Animals were treated with the recommended dose of EPN (1 mg/kg body weight) after taking the pre-treatment samples. Efficacy of EPN was tested with the faecal egg count reduction test (FECRT) and faecal cultures were performed on every farm from pooled faeces samples before and after treatment. Additionally the farmers completed a questionnaire. None of the gastrointestinal nematode populations of the 43 investigated farms were susceptible to EPN at the required level. The mean egg count reduction was 40%. None of the typical risk factors, such as production type, stocking rate, animal traffic and quarantine measures showed an association with the level of eprinomectin resistance. It can be concluded with 80% certainty that the prevalence of EPN resistance on goat farms is at least 95% in canton Berne.

The acid secretory capacity of the abomasal mucosa was studied in sheep experimentally infected with Ostertagia leptospicularis. The acidity of the abomasal contents, permanently recorded by a pH probe located inside the abomasum, decreased markedly to mean levels between pH 5 and 6. Subcutaneous administration of histamine or carbachol successfully stimulated acid secretion (pH 3.4). The results indicate that the abomasal mucosa harboured a population of functional parietal cells which were also identified immunohistochemically (H(+)/K(+)-ATPase). Ultrastructural investigation before stimulation revealed that the majority of these cells was in a resting state. Despite high serum gastrin levels, the acid secretion was blocked either at the level of the parietal cell or the enterochromaffin-like cell by an unknown factor, possibly mediated by the parasites. This is the first report of a parietal cell dysfunction associated with a nematode infection in the abomasum. It is suggested that the parasites induce changes in their environment which favour their survival and/or increase their reproduction.

Nine lambs, approximately 9 months of age were allocated to three groups (A, B, C), with three animals in each. Sheep in Groups A and B were trickle-infected with doses of 1000 third-stage larvae (L3) ofOstertagia leptospicularis(five times per week) over periods of 7.5 and 10.5 weeks, respectively, and were subsequently treated with fenbendazole (7.5 mg/kg). Approximately 3 weeks after anthelmintic treatment, all sheep were challenged with a single dose of 100 000 L3, whereas sheep of Group C received the same dose as a primary infection. Sheep of Groups A and B were almost completely refractory against the challenge infection, as indicated by negative faecal egg counts and adult worm burdens. A relatively high infection level was present in the sheep of Group C. The results indicate that a comparatively short immunization period of 7.5 weeks is sufficient to protect lambs against subsequent larval challenge. During immunization, the pepsinogen-, gastrin- and IgA-responses were similar in the individual sheep. In contrast to parasite-specific IgG1and IgG2levels, IgA decreased rapidly after cessation of trickle infection and parallel anthelmintic treatment, and may therefore indicate current exposure to parasite antigen. After challenge, the majority of the immunized sheep exhibited immediate and short-term responses of pepsinogen, gastrin and IgA in the serum. The time course and the level of each of these responses were very similar in the individual sheep, suggesting that the release of pepsinogen, gastrin and IgA into the circulation was influenced by related mechanisms.

The Cryptosporidium ITS1, 5·8S and ITS2 rDNA regions from a number of Cryptosporidium isolates from different hosts and geographical areas were cloned and sequenced in order to investigate the extent of sequence heterogeneity between human and cattle-derived isolates from different geographical locations and also between isolates of Cryptosporidium from different hosts such as cats, pigs, mice and a koala. Calf-derived isolates from different continents were virtually identical as were human-derived isolates from the UK and Australia. Genetic differences between Cryptosporidium isolates were extensive and were in fact greater than the level of nucleotide divergence between Toxoplasma gondii and Neospora caninum rDNA sequences. Based on the sequence information derived from this study, PCR–RFLP of the ITS1 region was undertaken in order to directly amplify and genotype Cryptosporidium isolates from different hosts. This PCR–RFLP approach can now be used for molecular epidemiology studies, circumventing the need for costly sequencing and allowing a wider range of genetically different isolates to be examined.

A 298 bp region of the Cryptosporidium parvum 18S rDNA and a 390 bp region of the acetyl-CoA synthetase gene were sequenced for a range of human and animal isolates of Cryptosporidium from different geographical areas. A distinct genotype is common to isolates from cattle, sheep and goats and also an alpaca from Peru and is referred to here as the ‘calf’-derived Cryptosporidium genotype. Another genotype of ‘human’-derived isolates also appears to be conserved amongst human isolates although humans are also susceptible to infection with the ‘calf’ Cryptosporidium genotype. Mice and pigs carry genetically distinct genotypes of Cryptosporidium. Three snake isolates were also analysed, 2 of which exhibited C. muris genotypes and the third snake isolate carried a distinct ‘mouse’ genotype.

The effect of the oxfendazole pulse release bolus (OPRB) administered at turnout, in May, or in mid-July on the development of infections with gastrointestinal nematodes and lungworms in first year grazing calves was investigated with three groups of nine animals, all grazing the same pastures in the Swiss midland region. In the calves of Group A (OPRB on 21 May) less than 20 eggs per gram of faeces (e.p.g.) and less than three Dictyocaulus larvae per 10 g (1.p.10 g) of faeces were shed for a period of 126 and 140 days respectively. Towards the end of the grazing period calves of this group excreted significantly higher levels of lungworm larvae (P0.05) compared with the other groups. Prior to OPRB administration on 14 July, the calves of Group B developed subclinical infections with trichostrongyles and lungworms which were similar to the untreated control Group C. By 4 weeks after bolus-administration the excretion of trichostrongylid eggs and lungworm larvae declined to levels below 20 e.p.g. and six l.p.10 g respectively. Serum pepsinogen values of the calves of Groups A and B were significantly lower (P0.05) compared with the control animals on days 84 and 98 after turnout and reflected mainly subclinical infections. With the exception of one Group A calf developing clinical parasitic gastroenteritis (p.g.e.) at the end of the season, clinical disease was not observed in the treated calves, while seven out of nine control animals grazing on the same pastures exhibited clinical p.g.e. with mean serum pepsinogen values exceeding 4400 mU tyrosine. Calves of Groups A and B gained significantly more weight (P0.01) compared with Group C (+36 kg and +41 kg respectively); differences between Groups A and B were not significant. The results indicate that in mixed grazing systems of treated and untreated calves, which are often found in the alpine region, administration of the OPRB in May or July provided good results with respect to performance of the calves. However, late administration of the OPRB has the additional advantage of coverage of the period of higher infection risk with trichostrongyles and lungworms in the late season until stabling, and should therefore be recommended.

Four groups of three lambs were used to investigate the pathophysiological changes during the development of a protective immunity against Ostertagia leptospicularis induced by a trickle infection. Three groups (A, B and C) were infected daily with 1000 third-stage larvae (L3) for a period of 26 weeks; group D remained uninfected until challenged. Egg excretion ceased after about 10 weeks in groups A, B and C and at the end of the trickle infection no parasites were found in group A sheep after slaughter. The sheep of groups B and C were highly refractory to two challenge infections, with 100,000 and 200,000 L3, given four and 17 weeks after the end of the trickle infection. Both challenge infections were followed by short term increases in the concentrations of gastrin and pepsinogen in the serum. Group C sheep were immunosuppressed with flumethasone during the second larval challenge and had higher pepsinogen concentrations but similar gastrin concentrations to the untreated sheep of group B.

In the alpine region, mixed grazing systems with cattle of different age, origin and prophylaxis against trichostrongylid infections are most common. Under these conditions the administration of anthelmintic devices to susceptible calves is frequently postponed to June or July to achieve a better protection during the period of increased pasture infectivity in summer and autumn. In a field experiment with 27 first-year grazing calves a morantel sustained-release trilaminate bolus (MSRT, Pfizer) was given to two groups (Groups A and B) of nine naturally infected calves each, on 22 July. Calves of Group B were moved to a clean pasture (B) 1 day later, whereas the calves of Group A remained on the previous pasture (A) together with nine untreated calves (Group C). The contamination with infective larvae (L3) on Pasture A remained below 1000 L3 kg-1 dry matter, which was sufficient to produce clinical parasitic gastroenteritis in five of nine control calves. The MSRT bolus reduced the mean egg output by more than 90% within 14 days after administration and prevented clinical parasitic gastroenteritis in the calves of Groups A and B. Owing to the persisting infection risk on Pasture A, the mean serum pepsinogen levels reached about 3000 mU tyrosine in the calves of Group A in September compared with approximately 2000 mU in Group B grazing the clean pasture. However, the differences in pasture contamination were not reflected in the mean bodyweight of the calves, which were 20 kg heavier at the end of the trial in both MSRT-treated groups compared with the control calves (P < 0.01). As there is a high probability that a moderate larval contamination is present on prealpine and alpine community pastures in summer, the metaphylactic use of an MSRT bolus in mid-July is likely to limit trichostrongylid infections within a subclinical range and thus provides sufficient protection of susceptible calves against parasitic gastroenteritis.

Publisher Summary This chapter focuses on Gastrointestinal Nematodes [“GIN”] of cattle and small ruminants, mainly covering the situation in Western Europe. Until recently, organic animal husbandry has relied largely on conventional veterinary approaches for the control of diseases and parasites. Among the numerous species of arthropods, helminths and protozoa living as parasites in or on farm animals, helminths present the most important group from an animal welfare standpoint as well as an economical standpoint. The quantities of antiparasitic drugs sold worldwide in the farm animal sector are almost equal to the quantities of antibiotics. Also comparable to antibiotics, the widespread use of anthelmintics has led to a severe problem with resistance to these compounds. Development of anthelmintic resistance is a major problem particularly in the GIN of small ruminants. A number of promising approaches for reducing the intensity of anti-parasitic drug treatments in low input and organic farms using complementary helminth control exist, but most of them are still at an experimental stage. Even those strategies where good progress has been made and which have proven to be beneficial, still have not been adopted in practice to a wide extent. Thus, besides ongoing research activities, the education of farmers and transfer of the techniques into the field is a critical issue, which has not been successfully addressed in the past.

A cross sectional study was conducted to determine the prevalence and significance of endoparasitic infections in South American Camelids (SAC) in Switzerland. Qualitative and quantitative coproscopic examinations were performed in 38 farms during the grazing period. Management practices with possible interference with parasitic infections were analyzed. On the farm level prevalences of endoparasitic infections were: trichostrongyles 87%; Trichuris sp. 74%; Capillaria sp. 68%; Nematodirus battus 63%; Nematodirus sp. 53%; Dicrocoelium dendriticum 34%; Moniezia sp. 8%; Fasciola hepatica 5%; protostrongylids 5%; Eimeria macusaniensis 68%. The level of helminth egg excretion was generally low. The highest values were recorded for trichostrongyles with an average of all investigated farms of 53 eggs per gram of faeces. The mean trichostrongyle egg output was approximately three-fold in SAC on farms that also kept sheep and/or goats, although this difference was not significant (P = 0.11). Clinical trichostrongylidosis was not reported from any of the farms. The low infection level with gastrointestinal nematodes is attributed to the defaecation behaviour of the SAC depositing their faeces focally on small spots on pasture. As a consequence, pasture infectivity is largely restricted to the area adjacent to the dung piles. Dicrocoeliosis is regarded as the most relevant parasitic infection of llamas and alpacas in Switzerland causing severe clinical symptoms and death in untreated animals. Sixteen per cent of the owners regularily treated their herds against dicrocoeliosis using praziquantel at a dose of 50 mg/kg body weight orally.

The objective of the study was to examine the effect of dried and ensiled sainfoin (Onobrychis viciifolia) on established populations of Haemonchus contortus (abomasum) and Cooperia curticei (small intestine) in lambs under controlled conditions. Twenty-four parasite naïve lambs were inoculated with a single dose of infective larvae of these parasites 28 days prior to the start of the feeding experiment. Twenty-four days post-infection, 4 days prior to the start of the feeding experiment, animals were allocated to four groups according to egg excretion, live weight and sex. Groups A and B received sainfoin hay and control hay, respectively, for 16 days. Groups C and D were fed on sainfoin silage or control silage for the same period. Feeds were offered ad libitum and on the basis of daily refusals were supplemented with concentrate in order to make them isoproteic and isoenergetic. Individual faecal egg counts on a dry matter basis (FECDM) were performed every 3-4 days and faecal cultures and packed cell volume (PCV) measurements were done weekly. After 16 days of experimental feeding, all animals were slaughtered and adult worm populations were determined. The consumption of conserved sainfoin was associated with a reduction of adult H. contortus (47% in the case of hay, P0.05; 49% in the case of silage, P=0.075) but had little effect on adult C. curticei. Compared to the controls, H. contortus specific FECDM was reduced by 58% (P0.01) in the sainfoin hay group and by 48% (P=0.075) in the sainfoin silage group. For both sainfoin feeds FECDM specific to C. curticei were significantly decreased when compared to the control feeds (hay 81% and silage 74%, both tests P0.001). Our data suggest that different mechanisms were responsible for the reduction in FECDM in response to feeding tanniferous fodder. For H. contortus, the decrease seemed to be due to a nematocidal effect towards adult H. contortus. In contrast for C. curticei, the reduction in FECDM appeared to be a result of a reduced per capita fecundity. For both, hay and silage, an antiparasitic effect could be shown, offering promising perspectives for the use of conserved tanniferous fodder as a complementary control approach against GIN.

For the last 50 years the control of gastro-intestinal nematodes (GIN) in grazing animals has almost entirely been alleviated by the use of anthelmintics. Due to development of resistance against the drugs, especially in the GIN of sheep and goats it has become necessary to develop new, innovative strategies such as the use of nematode destroying fungi. Despite experiments to employ various species against plant and animal parasitic nematodes were already attempted in the 1930's, it was not until the 1990's when selection by simulating passage through the gastro-intestinal tract of cattle led to isolation of the fungus Duddingtonia flagrans that a major breakthrough was achieved. This fungus, producing sticky three-dimensional network and now isolated world-wide, is special due to its capacity to prolifically produce high numbers of thick-walled resting spores, chlamydospores. These spores survive passage through the gastro-intestinal tract of grazing livestock and are capable of growing and subsequently trap nematodes, including larval stages of parasitic nematodes. The great potential of this fungus as a biological control agent has been demonstrated through numerous trials with cattle, sheep, horses, and pigs. But these trials have also pointed towards some potential limitations in the activity spectrum of the fungus (Dictyocaulus, Nematodirus) beside the whole group of parasites spreading through infective stages protected inside resistant eggs (e.g. Ascaris, Trichuris). So far, in the few reported studies conducted, no negative environmental impact has been found, but it is important that further studies are conducted on this important issue. Although the potential use of D. flagrans chlamydospores has been verified through numerous trials it is necessary to develop practical delivery systems such as slow release devices, feed-blocks or similar to be able to implement this tool in future integrated control strategies. Such control strategies could include the use of biological control, grazing management, smart use of existing drugs, parasite resistant animal breeds, bioactive forages, and possibly vaccines.

The aim of the study was to investigate the longitudinal changes of exsheathment of ovine and bovine 3rd-stage strongylid larvae in an artificial rumen (RUSITEC) and to compare the results with in vivo data obtained from rumen-fistulated sheep. Infective larvae were incubated in nylon mesh bags in the sheep rumen or the RUSITEC apparatus for periods of 1, 6 and 12 h, respectively. The 12 h exsheathment rates in the rumen and the RUSITEC apparatus (in parentheses) were as follows: Haemonchus contortus: 100% (100%), Ostertagia circumcincta: 100% (76%), O. leptospicularis: 100% (100%), O. ostertagi: 53% (59%), Trichostrongylus axei: 100% (100%), T. colubriformis: 37% (36%), Cooperia curticei: 94% (76%), C. oncophora: 95% (89%), Nematodirus filicollis: 0% (N.D.), N. spathiger: 11% (15%), N. battus: 7% (5%), Oesophagostomum venulosum: 17% (9%), Chabertia ovina: 7% (2%), Dictyocaulus filaria: 1% (N.D.). Larvae of Nematodirus spp. and T. colubriformis showed a quick rise of the exsheathment rate 2 h after transfer into the abomasum. These results confirm that exsheathment generally occurs in the part of the gastrointestinal tract immediately anterior to the habitat of the adult parasite. The overall similar course of exsheathment in both systems indicates that the essential stimuli for exsheathment were generated and maintained under in vitro conditions of the artificial rumen. In both systems, the bicarbonate concentration and the pH reflected a similar status of the H2CO3/HCO buffer system, which is known to provide the essential stimuli for larval exsheathment of the abomasal species. These results give evidence that the RUSITEC system represents a valid system for studying the kinetics of exsheathment of strongylid nematodes under in vitro conditions. For 7 of the species investigated the obtained results represent the first data on larval exsheathment in vivo and in vitro.