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Highlights • African Animal Trypanosomosis is highly prevalent in Northern Togo. • Trypanocidal drug resistance is a livestock health concern. • Rational drug use strategies permit to reduce significantly trypanosomes infection in trypanocidal drug resistance villages. Abstract The study assessed an integrated trypanosomosis control strategy in drug-resistant hotspot villages of northern Togo. This strategy comprised (i) rational trypanocidal drug use in symptomatic cattle, (ii) vectors and ticks control by targeted bi-monthly insecticidal spraying of the lower body parts of cattle and (iii) strategic deworming with Albendazole in the beginning and the end of the rainy season. The program was implemented between June 2014 and October 2015 in four villages in northern Togo, which had been previously identified as drug resistant hotspots for diminazene diaceturate (DA) and isometamidium chloride (ISM). The integrated control strategy was implemented in eight cattle herds at risk of the disease from two villages. Twelve herds from two other villages served as controls where trypanosomosis management and deworming remained under control of the farmers. Trypanocidal drug use during the study period was recorded by the intervention team based on the farmers' reports and own observations. Cattle herds were followed-up for trypanosomosis symptoms which were recorded at 3 to 4-month intervals, while extensive trypanosome diagnostics and recording of the packed cell volume were done before and after the intervention. Intervention herds had a significantly lower risk of trypanosome infection with a risk ratio of 0.18 (95% CI: 0.04, 0.91; p = 0.03), but no significant effect on mean packed cell volume was observed. However, trypanocidal treatments per animal per year were lower in intervention herds compared to control herds (0.3 vs 5 for DA and 0.8 vs 2 for ISM). This study demonstrates that the implementation of an integrated best-bet strategy leads to a reduced trypanosome prevalence under lowered trypanocidal use. [ABSTRACT FROM AUTHOR]

Abstract Bovine trypanosomosis is a problem in the livestock industry in Nigeria. A longitudinal survey of cattle sampled during the wet and dry seasons was conducted from April 2016 to March 2017. Blood samples were collected by random sampling from 745 cattle in southwest Nigeria and screened for trypanosomes by internal transcribed spacer–polymerase chain reaction (ITS-PCR). Cattle positive for Trypanozoon DNA were further screened with the Rode Trypanozoon antigen type (RoTat) 1.2 PCR and Trypanosoma brucei gambiense glycoprotein (TgsGP) genes for T. evansi and T. b. gambiense respectively. Trypanosome DNA was amplified in 23.8% (95%CI: 20.8–26.9) of cattle with significantly higher prevalence in wet season (95%CI: 22.9–30.8) when compared to the dry season (95%CI: 14.3–23.6). A high prevalence was observed in Fulani cattle farms 54.1% (95%CI: 42.78–64.93%) while the prevalence was lower in institutional farms 14.7% (95%CI: 10.10–20.97%). Trypanosoma vivax was the most prevalent trypanosome observed (11.54% (95%CI: 9.44–14.04%)), followed by T. congolense 8.5% (95%CI: 6.67–10.67%) T. b. brucei 4.8% (95%CI: 3.51–6.62%) and T. evansi 1.74% (95%CI: 1.02–2.96%). Mixed infections were observed in 2.8% (95%CI: 1.85–4.27%) of cattle. Seasonal variation revealed a predominance of T. congolense and T. vivax in wet and dry season, respectively. The high prevalence of Trypanosoma species in cattle indicates a need for expanded surveillance for AAT in southwest Nigeria. Migration, settlement patterns, increased marketing and management types were some of the risk factors identified for AAT. Graphical abstract Unlabelled Image Highlights • First molecular identification of trypanosomes in relation to management systems • Fulani cattle were mostly positive for trypanosomes, while institutional cattle were least positive. • T. vivax and T. congolense were mostly present in dry and wet seasons, respectively. • Trypanosomes were positive in clinically healthy cattle. [ABSTRACT FROM AUTHOR]

Previous studies have shown that a 64-kDa antigen (p64) that was purified from the Venezuelan TeAp-N/D1 isolate of Trypanosoma (Trypanozoon) equiperdum corresponds to the soluble form of its predominant variant surface glycoprotein (VSG), and exhibited cross-reactivity with Trypanosoma (Duttonella) vivax . The course of experimental acute infections of bovines with T. vivax were followed by measuring whole anti-p64 antibodies and specific anti-p64 IgG and IgM antibodies in animal sera by indirect enzyme-linked immunosorbent assay (ELISA). The value of p64 to diagnose bovine trypanosomosis was also examined using 350 sera from healthy and T . vivax -infected cows living in a trypanosomosis-endemic and enzootic stable area, and 48 sera obtained during a trypanosomosis outbreak. Serological assays showed that ∼70–80% of the infected sera contained anti-p64 antibodies, based on the comparative immunodetection of the T . equiperdum clarified antigenic fraction used as a reference test. In the absence of a gold standard, Bayesian analysis for multiple testing estimated a sensitivity and specificity of 71.6% and 98.8%, respectively, for the indirect ELISA using p64 as antigen. An apparent prevalence of 37.7% for bovine trypanosomosis infection was also estimated with a Bayesian approach when the p64 ELISA test was used. Employing blood from acute infected cows, the indirect ELISA response against p64 was contrasted with the microhematocrit centrifuge method and analyses by polymerase chain reaction (PCR) using specific primers targeting the inter-specific length variation of the internal transcribed spacer 1 region of the 18S ribosomal gene. The efficiency of p64 for the detection of anti-trypanosome antibodies in acute infected bovines was also corroborated serologically by comparing its response to that of the Indonesian Trypanosoma evansi Rode Trypanozoon antigen type (RoTat) 1.2 VSG, which possesses high specificity and sensitivity. As expected, PCR was the best method to detect parasites and diagnose bovine trypanosomosis; however, a substantial level of concordance (Cohen’s κ = 0.667) was obtained when serological tests using p64 and RoTat 1.2 VSG were compared. Additionally, an agglutination assay was designed using p64 covalently coupled to carboxylate-modified latex microparticles, which was proven here to be suitable for a fast qualitative diagnosis of bovine trypanosomosis. [ABSTRACT FROM AUTHOR]

Abstract: Endemic animal diseases such as tsetse-transmitted trypanosomosis are a constant drain on the financial resources of African livestock keepers and on the productivity of their livestock. Knowing where the potential benefits of removing animal trypanosomosis are distributed geographically would provide crucial evidence for prioritising and targeting cost-effective interventions as well as a powerful tool for advocacy. To this end, a study was conducted on six tsetse-infested countries in Eastern Africa: Ethiopia, Kenya, Somalia, South Sudan, Sudan and Uganda. First, a map of cattle production systems was generated, with particular attention to the presence of draught and dairy animals. Second, herd models for each production system were developed for two scenarios: with or without trypanosomosis. The herd models were based on publications and reports on cattle productivity (fertility, mortality, yields, sales), from which the income from, and growth of cattle populations were estimated over a twenty-year period. Third, a step-wise spatial expansion model was used to estimate how cattle populations might migrate to new areas when maximum stocking rates are exceeded. Last, differences in income between the two scenarios were mapped, thus providing a measure of the maximum benefits that could be obtained from intervening against tsetse and trypanosomosis. For this information to be readily mappable, benefits were calculated per bovine and converted to US$ per square kilometre. Results indicate that the potential benefits from dealing with trypanosomosis in Eastern Africa are both very high and geographically highly variable. The estimated total maximum benefit to livestock keepers for the whole of the study area amounts to nearly US$ 2.5 billion, discounted at 10% over twenty years – an average of approximately US$ 3300 per square kilometre of tsetse-infested area – but with great regional variation from less than US$ 500 per square kilometre to well over US$ 10,000. The greatest potential benefits accrue to Ethiopia, because of its very high livestock densities and the importance of animal traction, but also to parts of Kenya and Uganda. In general, the highest benefit levels occur on the fringes of the tsetse infestations. The implications of the models’ assumptions and generalisations are discussed. [Copyright &y& Elsevier]

Abstract: Animal trypanosomosis is a serious constraint to livestock productivity in tropical and sub-tropical countries. The pathogenic trypanosomes in bovidae are Trypanosoma congolense, T. vivax, T. brucei and T. evansi. Current serological tests to detect trypanosome infections are based on the use of whole trypanosome lysates; their potential is limited by antigen instability, lack of reproducibility and lack of test specificity due to the antibody''s long persistence after treatment. The development of new tests based on recombinant technology that could be standardized and applied on a large scale at low cost would be very helpful. The major invariant antigen recognized by T. congolense infected cattle belongs to the heat shock protein (HSP) 70 family and is closely related to mammalian Immunoglobulin Binding Protein (BiP). To improve the initial ELISA based on a recombinant fragment of HSP70/BiP, we developed an inhibition ELISA using an anti-BiP monoclonal antibody and a full-length fusion protein expressed in E. coli. Here we report on the development of the test and provide an initial assessment of its performance using sets of sera from experimental infections and from naturally infected cattle maintained in tsetse infested areas of Africa. The HSP70/BIP-based inhibition ELISA shows a good sensitivity in cattle experimentally infected with T. congolense, with an improved sensitivity in secondary infections. One major advantage, particularly for its further application in national laboratories, is that one single set of reagents and one single procedure are sufficient to apply on different mammalian host species infected with different trypanosome species. [Copyright &y& Elsevier]

Abstract: Trypanosomosis caused by Trypanosoma vivax has been a constraint for cattle production in the Bolivian lowlands, since it was introduced in 1996. Flooded areas like the Bolivian Pantanal have a suitable environment for the presence and transmission of Salivarian trypanosomes and farmers from that region often report trypanosomosis-like problems on their farms. The objective of the present study, therefore, was to characterize the epidemiology of bovine trypanosomosis in the Bolivian Pantanal. In order to achieve this objective, 202 cattle from the province of Angel Sandoval and 209 cattle from the province of German Busch were randomly sampled (the Pantanal is located in both provinces). Twenty-nine farms in both provinces were visited, the farmers interviewed, and biologic samples collected from their cattle. Samples were submitted for parasitological and PCR evaluation and the prevalence of bovine trypanosomosis was estimated for each province. Laboratory results were correlated with the sampled animals packed cell volume (PCV) and body condition (BC) scores and the observed T. vivax parasites measured for morphometry analysis. Results from this study show differences in morphometric measures between T. vivax parasites from each province. Differences between provinces were also observed in the T. vivax-related disease situation. While in Angel Sandoval the PCV and BC of T. vivax-affected animals were significantly lower than those of the T. vivax-negative animals, in German Busch no differences were observed in the PCV and BC of T. vivax-positive or negative animals. Animal prevalence of T. vivax in Angel Sandoval was 27.79% (95% CI: 14.52–44.28) and in German Busch was 19.03% (95% CI: 9.19–30.75). The T. evansi animal prevalence in each province was 0.99% (95% CI: 0.27–2.99) and 5.71% (95% CI: 2.43–12.19), respectively. Based on questionnaire and laboratory results, it was concluded that trypanosomosis is a primary constraint for cattle production in the Bolivian Pantanal. [Copyright &y& Elsevier]

Abstract: We tested the efficacy of two formulations of isometamidium in a tsetse-infested farm in North Cameroon from 20 August 2000 to 5 January 2001. A total of 90 adult cattle were used in three groups of 30 each corresponding to two treated and one untreated control. Drug efficacies were evaluated in terms of reduction of parasite incidence in the host''s blood, maintenance of packed-cell volume (PCV) and weight gains. Both drugs reduced the incidence of parasites even though re-infections 2 weeks after treatment were common. PCV values were similar in both treated groups but higher than in the untreated control. Body weight changes followed a similar trend with the control losing weight from a mean of 427±119kg at the beginning to 398±93kg in 4 months. Weights increased from 375±76 and 396±110 to 396±69 and 418±112kg in the Veridium® and Trypamidium® groups, respectively. Efficacy was similar between the two formulations of isometamidium in the prophylaxis of bovine trypanosomosis. However, the presence of parasites in some animals barely 2 weeks after treatment suggested that either infections were not cleared or residual drug effects were not sufficient to prevent re-infections. [Copyright &y& Elsevier]

In this study, we evaluated the therapeutic efficacy of diminazene diaceturate at a dose of 7 mg/kg (DA), imidocarb dipropionate at 4.8 mg/kg (IMD), isometamidium chloride at 0.5 and 1.0 mg/kg (ISM 0.5 and ISM 1.0) and combinations applied through different methods to treat Trypanosoma vivax in experimentally infected calves. Thirty male Girolando calves were kept indoors and infected intravenously with T. vivax trypomastigotes (approximately 1 × 106). On D-1, the calves were randomized based on the quantity of infecting parasites per animal, yielding six groups of five animals each: G1: positive control group without treatment; G2 animals treated with DA on Day 0 intramuscularly (IM); G3 animals treated with IMD on Day 0 and D + 14 subcutaneously; G4 animals treated with ISM 0.5 on Day 0 IM; G5 animals treated with ISM 1.0 on Day 0 IM; G6 animals received DA on Day 0 and ISM 1.0 on D + 14, both IM. Throughout 180 days, blood samples were collected for the evaluation of T. vivax using the Woo, Brener and PCR methods. The results indicated that the treatment protocols with DA and/or ISM 0.5 and ISM 1.0 had high efficacy (100 %) against T. vivax. Interestingly, cattle that received ISM remained free of parasites until D + 180. In contrast, animals treated with IMD had relapsed T. vivax detected on the 10th and 14th days post-treatment (DPT). Cattle that received ISM 1.0 did not exhibit relapsed T. vivax in the blood, even after reinfection performed on the 50th DPT. However, treatment with DA on Day 0 failed to prevent a new infection of T. vivax on the 50th DPT. The animals that received ISM 1.0 had a transient decrease in packed cell volume similar to that found in the control group. The reappearance of T. vivax in herds in Brazil treated with DA likely occurred due to the short half-life of the drug and not necessarily due to T. vivax resistance to DA. [ABSTRACT FROM AUTHOR]