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Ancylostoma caninum is the most prevalent intestinal nematode of dogs, and has a zoonotic potential. Multiple-drug resistance (MDR) has been confirmed in a number of A. caninum isolates, including isolate Worthy 4.1F3P, against all anthelmintic drug classes approved for hookworm treatment in dogs in the United States (US). The cyclooctadepsipeptide emodepside is not registered to use in dogs in the US, but in a number of other countries/regions. The objective of this study was to evaluate the efficacy of emodepside + praziquantel, as well as three commercial products that are commonly used in the US for treatment of hookworms, against a suspected (subsequently confirmed) MDR A. caninum isolate Worthy 4.1F3P. 40 dogs infected on study day (SD) 0 with 300 third-stage larvae, were randomly allocated to one of five treatment groups with eight dogs each: pyrantel pamoate (Nemex®-2), fenbendazole (Panacur® C), milbemycin oxime (Interceptor®), emodepside + praziquantel tablets and non-treated control. Fecal egg counts (FEC) were performed on SDs 19, 20, 22, 27, 31 and 34. All treatments were administered as per label requirements on SD 24 to dogs in Groups 1 through 4. Two additional treatments were administered on SDs 25 and 26 to dogs in Group 2 as per label requirements. Dogs were necropsied on SD 34 and the digestive tract was removed/processed for worm recovery and enumeration. The geometric mean (GM) worm counts for the control group was 97.4, and for the pyrantel pamoate, fenbendazole, milbemycin oxime, and emodepside + praziquantel groups were 74.8, 72.0, 88.9, and 0.4, respectively. These yielded efficacies of 23.2%, 26.1%, and 8.8%, and 99.6%, respectively. These data support previous findings of the MDR status of Worthy 4.1F3P as treatments with pyrantel pamoate, fenbendazole and milbemycin oxime lacked efficacy. In sharp contrast, Worthy 4.1F3P was highly susceptible to treatment with emodepside + praziquantel., Graphical abstract Image 1

Albendazole and mebendazole are commonly used to control hookworm, but have shortcomings in their efficacy profiles. We assessed whether triple drug therapy (TDT) with albendazole, pyrantel pamoate, and oxantel pamoate was more effective than the co-administration of two drugs for the treatment of hookworm infections.A randomised, single-blind trial was done from Sept 27 until Nov 17, 2017, in Laos. Children (6-15 years) from six schools were invited to participate. Hookworm-positive children were randomly assigned (2:2:1:1) by a computer stratified list (block sizes of six and 12) to TDT with albendazole (400 mg), pyrantel pamoate (20 mg/kg), and oxantel pamoate (20 mg/kg); albendazole plus oxantel pamoate; pyrantel pamoate plus oxantel pamoate; or mebendazole (500 mg) combined with both pyrantel pamoate and oxantel pamoate (used as proof of concept to compare the two TDTs). Two stool samples were collected at baseline and follow-up (17-30 days after treatment) and analysed with the Kato-Katz method. The primary outcome was the proportion of hookworm egg-negative children at follow-up in all Kato-Katz slides (cure rate [CR]) in the TDT with albendazole, pyrantel pamoate, and oxantel pamoate group compared with the albendazole plus oxantel pamoate and pyrantel pamoate plus oxantel pamoate groups. Secondary outcomes were tolerability 3 h and 24 h after treatment, egg reduction rates (ERRs) against hookworm, and efficacy against concomitant soil-transmitted helminth infections. Participating children and field and laboratory technicians were masked to treatment allocation. All children with follow-up data were included in the primary analysis. This trial is registered with ClinicalTrials.gov, number NCT03278431.1529 children were assessed for eligibility, of whom 533 provided complete baseline data and 414 provided complete outcome data. The CR was higher for the TDT albendazole, pyrantel pamoate, and oxantel pamoate (116 [84%] of 138) than with albendazole plus oxantel pamoate (73 [53%] of 138; odds ratio 4·7, 95% CI 2·7-8·3; p0·0001) and pyrantel pamoate plus oxantel pamoate (36 [52%] of 69; 4·8, 2·5-9·3; p0·0001). The geometric ERR of the TDT albendazole, pyrantel pamoate, and oxantel pamoate (99·9%) was higher than that for albendazole plus oxantel pamoate (99·0%; difference in ERR 0·9 percentage points, 95% CI 0·5-1·4), and pyrantel pamoate plus oxantel pamoate (99·2%; 0·7 percentage points, 0·3-1·3). Adverse events were reported by six (1%) children 3 h and none 24 h after treatment, without any difference across treatment groups.TDT with albendazole, pyrantel pamoate, and oxantel pamoate could make a difference, in particular in the context of soil-transmitted helminth elimination. Pyrantel pamoate might be a useful alternative to prevent benzimidazole resistance; however, larger trials are needed to confirm this finding.Swiss National Science Foundation.

Diclidophoridae and Capsalidae are families of monogenean parasites that include some of the most pathogenic species for cultured finfish. In this study, the efficacy of praziquantel (PZQ) and a combination anthelmintic (PZQ, ivermectin, pyrantel pamoate and fenbendazole) commercialized under the name of Adecto® (Adler Pharma) were evaluated in vitro against adults and eggs of the diclidophorid Tagia ecuadori and the capsalid Neobenedenia melleni. Freshwater and formalin immersions were also evaluated against T. ecuadori for comparative purposes. In addition, the efficacy in vivo of Adecto® as a bath treatment to eliminate mixed infections as well as the median lethal concentration (LC50) of this drug in juvenile, healthy bullseye puffer fish (Sphoeroides annulatus) were determined. Triglycerides, hemoglobin, total protein and glucose levels were measured in three groups of fish: uninfected, infected and infected/treated with Adecto®. At the doses tested, PZQ did not have a concentration-dependent effect. Thus, 2.5 mg/L PZQ was 100% effective against adults of T. ecuadori after 20 h, and 3 mg/L killed 87% of N. melleni after 12 h. Adecto® had a concentration-dependent effect. The concentration required to kill all parasites in the minimum time was 20 mg/L Adecto® (12 h for T. ecuadori, and 16 h for N. melleni). Neither PZQ nor Adecto® were effective at inhibiting egg hatching. Adults of T. ecuadori were highly tolerant to freshwater; mortality was

Cyathostomins are the most common parasites of adult horses worldwide. Currently, the three classes of anthelmintics used to treat cyathostomin infections includes benzimidazoles, pyrimidines and macrocyclic lactones. However, due to widespread overuse, cyathostomins have developed varying degrees of resistance to all classes of anthelmintics. Fecal egg count reduction tests (FECRT) are currently used to determine the presence of anthelmintic resistance (AR), while egg reappearance periods (ERP) are used to investigate early macrocyclic lactone resistance. The objective of this study was to investigate the prevalence of cyathostomin pyrantel pamoate and ivermectin resistance, and to determine ERP at Prince Edward Island (PEI), Canada horse farms. In addition, fecal cultures and larval identification were performed to evaluate the prevalence of small and large strongyle egg shedding in PEI. Fecal egg counts (FEC) were performed on 270 horses on 14 horse farms across PEI. Horses with≥ 200 eggs per gram (EPG) met the inclusion criteria and were enrolled in the study (n = 101). The median (range) horses per farm was 7.5 (4–11) and 6.0 (4–8) for pyrantel pamoate and ivermectin groups, respectively. Horses were initially treated with 6.6 mg/kg of pyrantel pamoate orally (n = 101). Fecal egg counts were conducted every two weeks for 8 weeks post treatment. Once individual FEC were ≥ 200 EPG, horses were dewormed with 0.2 mg/kg of ivermectin orally (n = 80), and FEC were performed every 2–3 weeks for seven weeks. In this study the ERP was defined as the week the mean FECR were 10% below the initial mean two-week post treatment FECR. Fecal egg count reduction tests and ERP were used to evaluate the efficacy of each anthelmintic. Fecal culture was performed to confirm the shedding of cyathostomin eggs. Fecal egg count reduction tests detected pyrantel pamoate resistance on 5/14 farms. No signs of ivermectin AR were detected, while reappearance of eggs occurred at 4–6 weeks and 7–9 weeks for pyrantel pamoate and ivermectin, respectively. Fecal culture detected large strongyles on 5/14 farms, which accounted for 0.3% of strongyle type eggs cultured. The prevalence of Strongylus vulgaris among individual horses in this study was 2.8% and was detected on 2/14 farms. These findings will allow us to educate owners and veterinarians on appropriate anthelmintic protocols in PEI and can be used as a baseline for continued monitoring of ERP and anthelmintic resistance in this region.

Ancylostoma (A.) ceylanicum, one of the most common species of hookworms infecting dogs and cats, also causes patent infections in humans and is now considered to be the second most common hookworm species infecting populations in southeast Asia. A Japanese patient who returned from a visit to Thailand and Lao People's Democratic Republic (PDR) was presented with intermittent watery diarrhea with eosinophilia. Hookworm eggs were found in feces samples, and adult worms were confirmed to be present in the jejunum with capsule endoscopy and double balloon enteroscopy. A diagnosis of A. ceylanicum infection was made based on the morphology of the adult worms along with findings of a PCR-based molecular study using larvae obtained from a fecal sample culture. The infection was considered likely to have been obtained during a 1-month stay in a Laotian village, where the patient had eaten local food, worn sandals on bare feet, and lived as a local native villager, though he had stayed in modern hotels during the visit to Thailand.

Parasitic helminths of equids are capable of causing ill-thrift, clinical disease, and death. Although young horses are the most susceptible to parasitic disease and are the most intensively treated cohort, deworming regimens are rarely evaluated within this age group. This study objectively evaluated the impact of deworming regimen on fecal egg counts (FECs), growth rates, and body-condition scores in young Thoroughbreds. Forty-eight Thoroughbred foals from three central Kentucky farms were randomly allocated to two treatment groups: an interval dose program receiving bi-monthly rotations of pyrantel pamoate and ivermectin and a daily deworming group receiving daily rations of pyrantel tartrate feed additive throughout the study, oxibendazole at two months of age, and moxidectin treatments at 9.5 and 16.5 months of age. Pre- and post-treatment eggs per gram of feces (EPGs) of Parascaris spp. and strongyle family parasites, gel/paste dewormer efficacies, and monthly weights and body condition scores were collected. Ascarid and strongyle FECs were not significantly different between groups but were significantly influenced by horse age with strongyle counts continually increasing and ascarid counts peaking at 4.5 months of age. Reduced strongyle efficacies of ivermectin and moxidectin were observed on two farms with consistently low pyrantel pamoate efficacies on all three farms. Ivermectin also exhibited reduced ascarid efficacy. Average daily gain did not differ significantly between groups and was only significantly influenced by age, mirroring average daily gain reference data for Kentucky Thoroughbreds born in 2013. Body condition scores also did not differ between groups, remaining in the optimal range (5-6) for the duration of the study. Management practices resulting in growth rates matching the reference data and in optimal body condition scores compensate for the negative impacts of parasitism even in cases of reduced drug efficacy. Performance parameters can provide useful information in cases of suboptimal parasite control.

In the last decade there have been numerous reports of anthelmintic resistant cyathostomins in many parts of the world. The objective of the present study was to evaluate the efficacy of the commercially available anthelmintics against cyathostomin egg shedding in the Mid-Atlantic region of the United States. A total of 989 horses from 67 different farms located in southeastern Pennsylvania, northern Delaware, and northeastern Maryland were treated with fenbendazole, oxibendazole, pyrantel pamoate, ivermectin, or moxidectin at their recommended dosages. Fecal egg count reduction testing was used to determine the efficacy of each anthelmintic on those horses with fecal egg counts of ≥ 200 eggs per gram on the day of treatment (272 horses). Decreased efficacy (reduction of strongyle-type fecal egg counts by less than 90%) was found for fenbendazole, oxibendazole, and pyrantel pamoate, with only 6%, 21% and 43% of horses showing reductions of greater than 90%, respectively. The macrocyclic lactones showed high efficacy in all horses sampled in this study. The decreased anthelmintic efficacy detected in this study adds further evidence for the existence of resistant cyathostomins throughout much of the eastern United States. Findings from this study can be used to create a more sustainable approach for parasite control programs.

The main purpose of the research was to determine if three weekly samplings would produce consistent results for low strongyle egg shedders, generally associated with older horses. Strongyle egg counts per gram of feces (EPG) were done for 661 Thoroughbred mares on 14 farms in 2012-2013 once a week for three consecutive weeks. None of the mares had been treated with ivermectin or moxidectin for more than 90 days and with fenbendazole, oxibendazole, or pyrantel pamoate for more than 60 days. Strongyle EPG count data indicated that 38.3% of the mares were positive at first and second sampling, and 37.8%--at third sampling. There were 5.6-63.3% of horses positive per farm. Correlations between EPG count data in all three weeks are quite high (Rs = 0.84, p0.001). Level of horse infection was found to be dependent on horse age, type of farm and individual characters of horse. This study documented that strongyle egg counts (EPGs) from individual horses did not differ significantly between weeks. Thus, a single strongyle EPG count can be interpreted as indicative of the level of egg shedding for a given horse. These data support the current trend of not deworming all adult horses on a farm, so that high shedders can be identified and treated. This saves horse owners money and reduces development of potential drug resistance of parasites because of less frequent usage of antiparasitic compounds. Information from this study helps to conclude recommendations for parasite control in horses globally.

This paper describes the development and validation of a new multivariate calibration method based on diffuse reflectance mid infrared spectroscopy for direct and simultaneous determination of three veterinary pharmaceutical drugs, pyrantel pamoate, praziquantel and febantel, in commercial tablets. The best synergy interval partial least squares (siPLS) model was obtained by selecting three spectral regions, 3715–3150, 2865–2583, and 2298–1733 cm−1, preprocessed by first derivative and Savitzky–Golay smoothing followed by mean centering. This model was built with five latent variables and provided root mean square errors of prediction (RMSEP) equal or lower than 0.69 mg per 100 mg of powder for the three analytes. The method was validated according the appropriate regulations through the estimate of figures of merit, such as trueness, precision, linearity, analytical sensitivity, bias and residual prediction deviation (RPD). Then, it was applied to three different veterinary pharmaceutical formulations found in the Brazilian market, in a situation of multi-product calibration, since the excipient composition of these commercial products, which was not known a priori, was modeled by an experimental design that scanned the likely content range of the possible constituents. The results were verified with high performance liquid chromatography with diode array detection (HPLC–DAD) and high performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) and were in agreement with the predicted values at 95% confidence level. The developed method presented the advantages of being simple, rapid, solvent free, and about ten times faster than the HPLC ones.

Anthelmintic resistance is an increasing challenge for the control of equine parasites. The fecal egg count reduction test (FECRT) is the practical gold standard method for evaluating reduction in anthelmintic efficacy, but the interpretation is complicated due to high levels of variability. A hierarchical statistical model was described for analysis of FECRT data from multiple farms to evaluate the role of biological factors in determining the strongyle efficacy of pyrantel pamoate in a study performed in Denmark. The model was then used to describe two notions of farm efficacy, namely conditional and marginal efficacy. The median of the lower prediction limits was used to describe a robust classification rule. The performance of the methodology was evaluated using Monte Carlo simulations. The field study was performed on 64 Danish horse farms of different breeds. Of 1644 horses, 614 had egg counts ≥200 eggs per gram (EPG) and were treated. Individual coprocultures were performed for identification of Strongylus vulgaris from all horses pre-treatment. Thirty-one farms (48.4%) were positive for S. vulgaris , but pyrantel efficacy was unaffected by the presence of this parasite in the statistical model. Further, there were no significant effects of age, gender, or interactions between these, while the pre-treatment egg count was negatively associated with the egg count reduction. The statistical model classified 81.3%, 10.9%, and 7.8% of farms as no signs of resistance (NR), suspect resistance (SR), and resistance (RE), respectively. In comparison, arithmetic calculations classified 68.8%, 17.2%, and 14.1% in the same categories. Using 10,000 simulated data sets, the methodology provided a classification of farms into different efficacy categories with a false discovery of reduced farm efficacy rate equaling 8.74%. In addition, model-classification was unaffected by presence of single outlier horses in a separate simulation study.

Cyathostomins can cause a severe inflammation of equine large intestine characterized by substantial ventral edema and pronounced protein loss. Anthelmintic treatment of horses can result in a localized inflammatory response in the colonic mucosa of clinically normal horses. The aim of this study was to evaluate the systemic inflammatory response of ponies naturally infected with cyathostomins to single dose representatives of three anthelmintic drug classes, namely, oxibendazole, pyrantel pamoate, and moxidectin. Thirty ponies aged between 1 and 18 years of age were allocated to one of three anthelmintic treatments groups. Anthelmintic efficacy was evaluated using the fecal egg count reduction test performed weekly between 2 and 8 weeks post-treatment. Inflammatory responses were evaluated on days 0, 1, 3, 5, and 14 after treatment using hematology, measurement of the acute phase inflammatory markers serum amyloid A, fibrinogen, haptoglobin, and iron, and real-time PCR measurement of expression of the genes for interleukins 1-β and -10, tumor necrosis factor-α, and interferon-γ. There were subtle inflammatory responses to treatment, but cytokine expression was significantly associated with the interaction term between treatment group and anthelmintic efficacy (P0.05). Of the acute phase markers, only fibrinogen associated with treatment group. The findings suggest that systemic inflammatory responses subsequent to anthelmintic treatment of cyathostomin infection are minimal. It is possible that this response is 'buffered' by anti-inflammatory products of the parasites and/or the anti-inflammatory effects of the macrocyclic lactones.

blocked by gender and birth-weight and randomly allocated to two treatment groups: an interval dose program receiving bimonthly rotations of pyrantel pamoate and ivermectin beginning at two months of age and a daily deworming group receiving oxibendazole at two months of age, daily rations of pyrantel tartrate feed additive throughout the study, and moxidectin treatments at 9.5 and 16.5 months of age. In addition to collecting the performance parameters of monthly body weights and body condition scores, parasitological parameters, including preand posttreatment fecal egg counts (FEC) of Parascaris spp. and strongyle family parasites and calculated gel/paste dewormer efficacies were collected. Data were analyzed using mixed linear modeling. Ascarid and strongyle FECs were not statistically different between groups and were only significantly influenced by foal age; strongyle counts increased throughout the duration of the study and Parascaris spp. counts peaked at 4.5 months of age. Reduced efficacy of ivermectin and moxidectin against strongyles was observed on two farms respectivelywith consistently lowpyrantel pamoate efficacy on all three farms. Ivermectin also exhibited reduced Parascaris spp. efficacy. Monthly body weight converted to average daily gain was not significantly different between groups and was only significantly influenced by age, mirroring the average daily gain reference data for Kentucky Thoroughbreds born in 2013 generated by Kentucky Equine Research. Body condition scores remained in the optimal range (5-6) for the duration of the study and did not differ between groups. This maintenance of optimal performance parameters is likely due to both the excellent immuno-nutritional status of these well-managed horses and the generally low pathogenicity of these gastrointestinal parasites. Both measures of parasitological and performance parameters are useful in evaluating parasite control programs in maintenance of overall equine health.

Since 2002, selected populations of Parascaris equorum in several countries have been reported to survive treatment with macrocyclic lactone (M/L) anthelmintics. Clinical treatment failures are characterized by negligible fecal egg count reduction, but M/L resistance has been confirmed in ascarids by controlled efficacy testing. Resistance was selected by current parasite control practices for foals, which often include exclusive and excessively frequent use of M/L dewormers, thereby minimizing refugia within the host and in the environment. Chemical control of M/L-resistant isolates can be accomplished with pyrimidine and/or benzimidazole anthelmintics, but a few M/L-resistant populations have recently exhibited resistance to pyrantel pamoate as well. Some specimens of Oxyuris equi regularly survive treatment with macrocyclic lactones, but it is uncertain whether this constitutes resistance or merely confirms the incomplete oxyuricidal efficacy of virtually all broad spectrum equine anthelmintics. Variations in other biological parameters of Oxyuris and Parascaris, specifically atypical infection of older hosts and shorter prepatent periods, have been reported anecdotally. These changes may represent genetic modifications that have evolved in parallel with resistance as a result of anthelmintic selection pressure.

The expanding prevalence of Parascaris equorum populations that are resistant to macrocyclic lactone (ML) anthelmintics makes it desirable to identify dewormers which remain effective. The objective was to evaluate the efficacy of pyrantel pamoate in 14 suckling foals that had been infected orally with ∼600 larvated eggs of a P. equorum isolate selected for ML resistance (ML-R). Seventy days after inoculation, foals were weaned, housed individually, and fecal samples were examined frequently to detect the onset of patency. Between 73 and 80 days post-inoculation, all 14 foals developed P. equorum egg counts ≥150 eggs per gram (EPG). An initial cohort of eight foals was treated orally with ivermectin paste (200 μg/kg) 84–91 days post-inoculation. Egg counts were reduced by only 47% at 2 weeks after ivermectin treatment, confirming the ML-R status of the isolate. A second cohort of six foals was not treated with ivermectin. Within each cohort, eligible foals were allocated randomly to treated (pyrantel pamoate; n = 7) or untreated control (n = 7) groups. Treated foals were dosed orally on Day 0 with a paste formulation of pyrantel pamoate at 13.2 mg/kg. Mean ascarid egg counts of treated foals were reduced by 96.0% and 98.8% at 1 and 2 weeks post-treatment, respectively. On Day 14, foals were euthanatized and specimens of P. equorum were recovered from the gut contents, preserved in 10% formalin, and counted. Mean numbers of P. equorum adults recovered postmortem were significantly lower (P = 0.0031) in foals treated with pyrantel pamoate ( X ¯ = 1.7 ; range 0–16) compared to control foals ( X ¯ = 63.0 ; range 0–320). A paste formulation of pyrantel pamoate, at a dosage of 13.2 mg/kg, was 97.3% effective against a ML-R isolate of P. equorum.

In the present survey, 276 horses bred on 16 farms located in central and southern Italy were investigated for the presence of drug resistant cyathostomes by a Fecal Egg Count Reduction Test (FECRT). Sixteen to 20 animals were selected on each farm and randomly assigned to one of four equally sized treatment groups. Groups were treated with fenbendazole, pyrantel pamoate, ivermectin or moxidectin. Resistance to fenbendazole was declared on six farms (37.5%) and suspected in two farms (12.5%), with FECR values ranging from 41% to 88.3%. Resistance to pyrantel was found in two farms (12.5%) and was suspected in one case (6.2%), with FECR values ranging from 43% to 85.4%. Macrocyclic lactones remained effective on all farms. Only cyathostome third stage larvae (L3) were found in fecal cultures after treatment. This paper reports the first wide survey conducted in Italy for anthelmintic resistance in equine cyathostomes. The results indicate that multiple drug resistant equine cyathostomes are present in the central and southern regions of Italy. These data call for a geographically and numerically broader investigation of horse farms in all regions and for the development and implementation -among veterinarians, owners and managers of a plan to reduce the expansion of these anthelmintic resistant populations and control these important parasites.

The aims of studies in 2002 and 2003 on three farms with 76 foals naturally infected with Parascaris equorum were to (i) identify if the nematode was resistant to ivermectin and moxidectin, and (ii) confirm the effectiveness of fenbendazole and pyrantel pamoate for the parasite. Twelve clinical trials, each with a Fecal Egg Count Reduction Test, were conducted on two Thoroughbred and one Standardbred farms in southwestern Ontario, Canada. In each trial, Parascaris eggs/g feces were estimated for each foal pre- and post-treatment using the Cornell-Wisconsin double flotation and Cornell-McMaster dilution techniques. On each farm and for each trial, foals were randomized into treatment groups. Treatments were ivermectin, moxidectin, fenbendazole, pyrantel pamoate administered at the manufacturers' recommended dosages, and some foals were untreated. The overall efficacy for ivermectin was 33.5% (19 foals) and for moxidectin 47.2% (28 foals). Fenbendazole (16 foals) and pyrantel pamoate (21 foals) were highly effective for P. equorum each at 97.6%. For fenbendazole, 15 foals had 100% and for pyrantel pamoate 17 foals had >97% with 14 at 100%.

By collecting fecal samples every 2 weeks beginning at 2 months of age, 32 foals from a single Texas farm were monitored. The foals were administered ivermectin paste at the time of the first collection and again monthly. When foals had Parascaris egg counts higher 2 weeks after ivermectin treatment than at treatment, they were administered pyrantel pamoate at the manufacturer's recommended dose (6.6 mg/kg) or at twice the recommended dose (13.2 mg/ kg) when tapeworm eggs were also detected. An elevation or only minimal reduction (less than 75%) in Parascaris egg counts was seen 2 weeks after ivermectin treatment until the foals were 8 months of age, at which time there was an 85% reduction in fecal egg count after treatment. When pyrantel was administered at the manufacturer's recommended dose, a 42% to 84% reduction in egg counts occurred, but at 13.2 mg/kg there was a 98% to 100% reduction in fecal egg counts 2 weeks posttreatment. However, pyrantel failed to control strongylate egg counts even at the elevated dose, whereas ivermectin reduced strongylate fecal egg counts by greater than 99%, determined 2 weeks posttreatment. Pyrantel, but not ivermectin, lowered Parascaris egg counts. Ivermectin, but not pyrantel, lowered strongyle egg counts 2 weeks post administration. A single drug for all ages of horses approach to parasite control requires rethinking. Combinations of drugs or more careful evaluation of anthelmintics in foals may be necessary for continued parasite control.

Clinical trials using fecal egg count reduction tests and coproculture were conducted with yearlings and mares on a farm in 1997. Fecal samples were taken from each horse to estimate the number of strongyle eggs/g feces with Cornell-Wisconsin centrifugal flotation and Cornell-McMaster dilution techniques. Eleven of 15 yearlings, which had been on a daily feeding of grain with pyrantel tartrate for 66 d were found with strongyle eggs in feces. This was the first time the in-feed medication had been used on the farm. Nine yearlings were randomised into three groups; continuation of daily pyrantel tartrate or one treatment with pyrantel pamoate or moxidectin. Two of three yearlings given pyrantel tartrate or pamoate had no reduction in the eggs/g feces. These six yearlings were then given moxidectin and in all yearlings the eggs/g feces was reduced to zero. The 66 d of pyrantel tartrate use was an inadequate time for development of resistant cyathostomes and a hypothesis was the resistance was due to extensive use on the farm over many years of pyrantel pamoate at twice the label dose for control of tapeworms. That hypothesis was tested with 12 mares with strongyle eggs in the feces randomised into two treatment groups: pyrantel pamoate at label dose or moxidectin. Five of six mares given pyrantel had

The effect of two treatment programmes on egg shedding in dogs naturally infected with Toxocara canis, one based on a milbemycin oxime-praziquantel-lufenuron combination (SENTINEL) Spectrum; Group 1) and the other based on a febantel-pyrantel embonate-praziquantel combination (DRONTAL) Plus; Group 2), was compared in a study involving 104 suckling pups from three different kennels. The animals in Group 1 were treated at a minimum milbemycin oxime dose of 0.5 mg/kg bw starting at 2 weeks of age and subsequently every 4 weeks until reaching 26 weeks of age. The animals in Group 2 were treated every 2 weeks from week 2 until week 12 of age and then once at week 26 at a minimum febantel and pyrantel embonate dose of 15.0 and 14.4 mg/kg bw, respectively. Toxocara egg counts were determined fortnightly starting at 2 weeks of age and continuing until 26 weeks of age for every pup. Any adverse drug event was recorded during the trial. Both treatment programmes significantly reduced the zoonotic Toxocara egg shedding and were well tolerated by the pups. The pups in Group 1 showed lower average faecal egg counts and were found more frequently shedding no eggs than the pups in Group 2.

Laboratory golden hamsters (Mesocricetus auratus) were infected with Necator americanus under several different parasite and host conditions to optimize the model for testing anthelminthic drugs. The results confirmed that male hamsters were more susceptible to infection than females. Host age in the range of 5-15 weeks was not a factor that impacted on adult worm burden, and similar worm burdens were achieved using doses of 150, 250 or 500 N. americanus L3 (NaL3). The largest numbers of adult hookworms were recovered on days 21-28 post-infection, with a significant decrease at days 40-50 post-infection. Therefore adult worm recovery is maximal approximately 11-18 days prior to patency and host blood loss. From these studies a drug evaluation protocol was developed using 150 NaL3 as the infectious dose and then evaluating the anthelminthic effects of the drugs albendazole, tribendimidine, and pyrantel pamoate on days 21-28 post-infection. The model confirms the anthelminthic activity of albendazole, tribendimidine, and pyrantel pamoate and has the potential as a laboratory animal model to detect emerging drug resistance.

This study was conducted on a stud farm in Sweden to investigate the species composition of cyathostomins expelled in the faeces of horses after deworming using three different anthelmintic preparations. Twenty-seven horses excretingor = 200 strongyle eggs per gram faeces (EPG) were divided into three comparable groups and dewormed on day 0 with either of following compounds: 0.2 mg ivermectin per kg body weight (bw), 19 mg pyrantel pamoate per kg bw or 7.5 mg fenbendazole per kg bw. For each of the 3 days following anthelmintic treatment faeces was collected from individual horses and subsamples were fixed in formalin. Four days after the anthelmintic treatment all horses were re-treated with ivermectin and faeces was collected on day 5. Individual subsamples from each of the four sampling occasions were examined for cyathostomin nematodes. Sixty-three to 270 worms per horse were identified to the species level. The majority of the worms recovered were expelled during the first day from horses treated with ivermectin or pyrantel pamoate, and during the second day from horses treated with fenbendazole. Fifteen cyathostomin species were identified and the six most prevalent were Cylicocyclus nassatus, Cyathostomum catinatum, Cylicostephanus longibursatus, Cylicocyclus leptostomus, Cylicostephanus minutus and Cylicostephanus calicatus. These species composed 91% of the total burden of cyathostomins. The number of species found per horse ranged from 6 to 13, with an average of 9. No significant differences in species composition or distribution were found between the treatment groups. On day 5, i.e. 1 day after the last ivermectin treatment, 93% of the adult worms were recovered from horses in the fenbendazole group. This study showed that it was possible to identify cyathostomins expelled in faeces of dewormed horses, and that the most prevalent species corresponded to those found in autopsy surveys performed in other countries.

Electron and video-light microscopy analysis of the in vitro effects of pyrantel pamoate on Giardia lamblia. Experimental Parasitology 97, 9-14. Giardia infection is predominant in the small intestine of vertebrates, where the trophozoites attach to epithelial cells and adversely affect the microvilli and other epithelial cell structures. Giardiasis, the disease caused by this protozoan, is very common in developing countries and mainly affects children. Drugs currently used to treat Giardia infection, such as some benzimidazole derivatives, were originally designed to treat helminthic infections. Many of the drugs are known to cause severe side effects and disturbances to the patient. Using transmission electron microscopy and video-light microscopy, we studied the effects of pyrantel pamoate, a drug commonly used in the treatment of helminthic infections in horses and ruminants, on Giardia lamblia trophozoites. Pyrantel pamoate was administered to Giardia cells in four different concentrations. Using video-light microscopy, we observed the decrease in flagella beating frequency and severe changes in the lateral flange and in the general aspect of the cell. Using transmission electron microscopy, we observed changes in the cytoplasm and peripheral vesicles. The flagella and adhesive disk structure were not affected. Apparently, the effects of pyrantel pamoate are irreversible.

Research on benzimidazole-resistant Population S small strongyles began in a Shetland pony herd in 1974 at the University of Kentucky and has continued for over 25 years. The present update, for the period 1992–1999, evaluated activity of pyrantel pamoate (PRT) in field tests in the pony herd. Additional critical tests with PRT and oxibendazole (OBZ) were done in foals born in the herd. Activity of PRT was initially excellent in field tests, based on epg/lpg count data, but declined rapidly during the second full year of pyrantel treatments. Critical test data for small strongyles indicated efficacies of PRT were about 60% at the beginning of the present observations and this intermediate level of removal continued throughout the seven-year period except for 1994 (75%). Unusual was the finding that field test epg/lpg data on small strongyles indicated much lower activity of PRT than found in worm count data in critical tests. The previously reported ineffective activity of OBZ on this population of small strongyles continued. Data are presented on prevalence and drug activity on several species of internal parasites besides small strongyles.

Adsorption of polysorbate 80 in aqueous suspensions of 4% (w/v) pyrantel pamoate gave rise to an L -type adsorption isotherm that could be fitted by the Langmuir equation, allowing estimation of the amount of surfactant forming a monolayer (Γ max =2.12 mg g −1 ), and of the adsorption activity ( a =0.24). The surfactant adsorption film slightly decreased the magnitude of the zeta potential of the system with respect to the mean value for the corresponding aqueous suspension (−60.34 mV). These results and the results of stability studies suggest that the polysorbate 80 was stabilizing the suspensions through a steric mechanism. At low surfactant concentrations this steric stabilization was only partial, however, and redispersion of sedimented particles became more difficult than in the absence of polysorbate 80. For the entire range of polysorbate 80 concentrations studied, sedimentation volumes were low and were not correlated with redispersability times. The rate of dissolution of aqueous suspensions of 4% (w/v) pyrantel pamoate increased upon adding polysorbate 80, which is attributable to the surfactant's having aided wetting of the drug particles.

The egg output and humoral antibody response to scolex antigens of the equine tapeworm Anoplocephala perfoliata were monitored in naturally infected foals by an egg flotation/centrifugation method and an indirect enzyme-linked immunosorbent assay (ELISA). The study was performed on a stud farm in south-western Sweden between May 1994 and April 1995. Sequential blood and faecal samples were taken from 21 foals during their first summer on pasture and until tapeworm eggs were detected. Results were expressed separately for 10 and 11 foals born before and after the end of April 1994, respectively. Increased levels of antibodies were noticed from October and onwards in both groups whereas tapeworm eggs were detected in the faeces of all foals about 4 months later. The antibody response was similar in both groups but it was more pronounced in foals born before April 1994. All foals were treated in March 1995 with an oral paste formulation of pyrantel pamoate at a dose rate of 38 mg/kg bodyweight. Most animals responded to the anthelmintic treatment and one month later, tapeworm eggs were only detected in one out of the 18 foals examined one month after treatment. Thus, the treatment reduced the number of A. perfoliata egg positive horses by 94%. A concomitant decline in antibody levels was also observed. Western immunoblot analysis of sequential individual serum samples showed that at least 10 different scolex antigens in the molecular weight range 10-200 kDa were recognised. Banding intensities, especially of the 10 kDa, 45 kDa and 66 kDa proteins were different in the sequential sera taken during the course of infection.

Summary A 26-week study was conducted with 24 horses to compare the effectiveness of two different treatment regimens in reducing the number of tapeworm eggs per gram (EPG) of feces. Ten horses were treated daily with 2.6 mg/kg of pyrantel tartrate (approved normal dosage for nematodes). Eleven horses received pyrantel pamoate at 8-week intervals at 19.8 mg/kg (3X the normal use for nematodes). Three horses served as controls and received ivermectin at 8-week intervals. Levels of tapeworm EPG were monitored at 2-week intervals for the duration of the 26-week period of study. Prior to administration of the first treatment, all 24 horses had positive EPG counts. Following the second week of treatment, no tapeworm eggs were detected in fecal samples of the 10 horses treated with pyrantel tartrate. Of the 11 horses treated with 3X pyrantel pamoate at 8-week intervals, one to two at each sample collection date had positive tapeworm EPG counts through the tenth week following the initial treatment, that is, through two weeks following the second 3X pyrantel pamoate treatment. Of the three control horses treated only with invermectin, at least one, and sometimes all three, had positive EPG counts at each collection date, indicating continuous tapeworm infection.

Three fecal egg count reduction assays (FECR) and one critical trial were performed to determine the efficacy of pyrantel pamoate (PP) at 6.6 mg base kg−1 on a well managed stud farm in Louisiana where a loss of efficacy was suspected. Efficacy of PP based on FECR varied from 25% in mares to 83% in yearlings. Second treatments with PP 2 weeks following an initial treatment failed to reduce eggs per gram (EPG). A critical trial was performed to determine the cyathostome species resistant to PP. Three strongyle-naive ponies which acquired infections on the farm were used for this purpose. Following treatment with PP at the recommended dose, 11 species of cyathostomes remained in the intestine of the tracer ponies. Reduced efficacies (62%–88%) were noted for seven species. Resistance to oxibendazole (OBZ), which was > 90% effective on this farm in 1982, was also evaluated by FECR and found to exist. The results of one experiment indicate that dual resistance of parasites to PP and OBZ also exists.

Several compounds ( n = 13 single or combinations; most at therapeutic dosages) were evaluated between 1977 and 1992 in critical tests ( n = 91) against benzimidazole (BZ) resistant small strongyles (Population S) and several other species of internal parasites in Shetland ponies, mostly under 1 year old. The closed breeding herd, from which the test ponies were selected, had been treated every 8 weeks with cambendazole (CBZ) for 4 years (1974–1978) and oxibendazole (OBZ) for 14 years (1978–1992). Published field test data (1974–1992) on older ponies in the herd showed BZ resistance of small strongyles. Average efficacies in the present critical tests against small strongyles for OBZ ( n = 59 animals) were high in early years (95% or higher), but gradually declined to a low of 1% in 1991. Side-resistance of small strongyles was evident in critical tests ( n = 1–6/single drug or combination) for several other BZs and a pro-BZ; ivermectin and piperazine were highly active, but pyrantel pamoate exhibited weak activity. BZ resistance was evident for six small strongyle species ( Cyathostomum catinatum, Cyathostomum coronatum, Cylicocyclus nassatus, Cylicostephanus calicatus, Cylicostephanus goldi , and Cylicostephanus longibursatus ). Activity on bots, ascarids, large strongyles, and pinworms was essentially as expected, indicating no drug resistance.

Summary A practical parasite control program was evaluated in a 2-year clinical trial using pyrantel pamoate suspension (PYR) and ivermectin oral solution (IVM) in a seasonal rotation program, in comparison with continued use of IVM given at 2-month intervals. At least 15 horses in each of 2 treatment groups were distributed over 8 locations. In the alternation program, IVM was given twice (October, December) during the botfly (Gasterophilus spp.) season and again in April to treat against the lighter botfly season and to kill existing Onchocerca microfilariae prior to heavy Culicoides swarming. Pyrantel was given in February, June and August to continue suppression of strongyle infections and to treat against potentially developing Anoplocephala infections. In the program of IVM continuous use, the drug was given on the same schedule as either treatment on the alternation program. The course of strongyle infections was monitored by fecal sample analyses (EPG) at semimonthly intervals and by larval cultures of treatment pairs prepared at each treatment interval (alternation program) or at 4-month intervals (continuous IVM program). The strongyle egg count numbers were reduced to zero by the first IVM treatment, increased only slightly by the next treatment at 2 months, and repeated the reduced pattern with each treatment for 2 years. The alternation program in the first year had typical responses to each drug: IVM reducing strongyle EPG counts to zero which increased slightly at 2 months, followed by the PYR treatment, which reduced the strongyle egg counts for 4 weeks with rebound at 6 and 8 weeks. At the end of the first year and into the second, the IVM treatments of October and December established a zero or low strongyle EPG pattern which continued through the spring with PYR and IVM treatments. The second summer PYR treatments then maintained far better cyathostome control than had been reported for this drug. There may be a complementary or enhancing effect by prior treatment with ivermectin within the rotation protocol. The practical therapeutic compatibility between these 2 antiparasitics became obvious. Anoplocephala eggs were found in feces of some horses treated with IVM only, but no Anoplocephala eggs were found in post-treatment feces of horses treated on the alternation program. Strongyle larval cultures prepared as treatment pairs indicated high efficacy by ivermectin throughout the 2 years whether used alone or as a rotational drug, with improved cyathostome control by pyrantel pamoate. The combined use of EPG determinations and concurrent larval cultures in anthelmintic evaluations provide a greater spectrum of reliable results than from parasite egg counts alone.

The efficacy of six anthelmintics against natural infections of Baylisascaris procyonis in raccoons (n = 7 per drug) was determined in a series of critical tests. The drugs were given via moist cat food as a single dose or once daily for three consecutive days. Raccoons treated with pyrantel embonate (1 x 20 mg base kg-1 bodyweight (bwt.)), ivermectin (1 x 1 mg kg-1 bwt.), moxidectin (1 x 1 mg kg-1 bwt.), albendazole (3 x 50 mg kg-1 bwt.), fenbendazole (3 x 50 mg kg-1 bwt.) or flubendazole (3 x 22 mg kg-1 bwt.) expelled 1-198, 2-24, 2-14, 3-80, 2-70, or 2-35 B. procyonis stages, respectively, within the faeces. No roundworm was detected in any raccoon at post mortem examinations 7 days after the end of treatment. These results suggest that any of the six anthelmintics can be used at the dose rates tested in a deworming programme for captive raccoons.

SUMMARY T hree anthelmintics were compared for efficacy in reducing the egg production of Anoplocephala perfoliata in a herd of central Texas horses. Two trials were run, 1 in mares and the other in weanlings that were diagnosed as being infected with Anoplocephala by recovery of eggs in 5 g of feces with sugar centrifugation. Each animal was evaluated twice before treatment and again twice following treatment (at weeks 2 and 4 after treatment). The criteria for infection were the recovery of eggs on at least 1 occasion before treatment and the finding of eggs on 1 day following treatment. The mares were treated 1 time with either pyrantel pamoate at 13.2 mg/kg, nitazoxanide at 100 mg/kg, praziquantel at 1.23 mg/kg or remained as untreated controls. The weanlings were treated with pyrantel at 13.7 mg/kg nitazoxanide at 100 mg/kg or remained as untreated controls. The percentage reduction of patient infection in mares after treatment with pyrantel was 83%, with nitazoxanide was 78%, and with praziquantel was 83% and in controls was 17%. There was a 75% reduction of patient weanlings treated with pyrantel or nitazoxanide and a 17% reduction in untreated controls. The reduction of infection in all horses treated with any drug was significantly different from controls. All of the drugs were somewhat effective in the control of Anoplocephala, and there were no differences among the drugs in their effectiveness.

Studies on a Thoroughbred breeding farm in Ohio were done to: (1) compare the effects of daily administration of pyrantel tartrate feed pellets with monthly administration of a pyrantel pamoate paste to yearling horses (21 January–3 September); (2) assess the effects of daily pyrantel tartrate given strategically in spring/summer to foaling mares (1 April–16 August) and given for a prolonged period to barren mares (21 January–3 September); (3) determine if strategic medication of foaling mares with daily pyrantel tartrate protected their foals until weaning. There were no differences in cyathostome egg counts, pasture larval counts, body condition scores, or body weights of yearlings treated with daily pyrantel tartrate or monthly pyrantel pamoate. Both treatments failed to maintain fecal egg counts of yearlings below 100 eggs per gram (epg), and mean counts exceeded 400 epg (pyrantel pamoate) and 700 epg (pyrantel tartrate) in August and September, resulting in a sharp, but moderate increase in pasture infectivity in October. By contrast, prolonged or strategic use of daily pyrantel tartrate in mature horses were each highly effective in reducing pasture contamination and infectivity with cyathostome eggs and larvae respectively. Strategic medication of foaling mares provided protection of their foals until weaning and first treatment of foals was delayed until after weaning when mean strongyle counts exceeded 100 epg. Treatment of weanlings with pyrantel pamoate had little effect on egg counts. A comparative anthelmintic study with ivermectin, oxibendazole, and pyrantel pamoate confirmed earlier studies showing reduced efficacy of anthelmintics in young horses.

The effectiveness of the combination of pyrantel pamoate (5 mg kg-1) and ivermectin (6 micrograms kg-1) against the canine hookworms Uncinaria stenocephala and Ancylostoma caninum was determined. This combination is intended for monthly use as a heartworm preventative and for treatment and control of canine hookworms. The formulation was found to be effective (99.6% reduction in worm burdens) against both species of hookworms in experimentally infected dogs. No adverse effects due to the drug combination were observed in any dog during the course of this study.

The purpose of this study was to evaluate whether aged horses demonstrate statistically higher fecal egg counts (FECs) compared with middle-aged horses and to investigate systemic expression of proinflammatory cytokines in old and middle-aged horses treated with moxidectin compared with horses treated with pyrantel pamoate. Old horses (n = 21) and middle-aged horses (n = 19) were blocked by levels of inflammation and randomly allocated to one of the following treatment groups: group 1 (n = 8) old treated with moxidectin gel; group 2 (n = 9) old treated with pyrantel pamoate paste; group 3 (n = 4) old receiving no treatment; group 4 (n = 8) middle-aged treated with moxidectin gel; group 5 (n = 7) middle-aged treated with pyrantel pamoate paste, and group 6 (n = 4) middle-aged receiving no treatment. Fecal samples were collected on day 0 and again 14 days after treatment to determine FECs and presence of Strongylus vulgaris by polymerase chain reaction. Peripheral blood was also collected on day 0 and again at days 3, 5, and 14 after deworming for inflammatory cytokine analysis, along with routine hematological analyses. Results indicated that old horses have significantly higher FEC than middle-aged adults. Fecal egg counts declined significantly after anthelmintic treatment in both age groups of horses. Inflammatory markers exhibited differences between age groups and by anthelmintic treatment. In summary, this study provided evidence of different inflammatory and immunologic reactions to anthelmintic treatment in old horses. Moreover, the higher FECs found in the old horse group may have practical implications for parasite management routines on farms with representation of this age group.

A retrospective clinical study to evaluate the effects of paralyzing vermifuges on the course of intestinal obstructions complicating ascariasis was performed. Forty-two patients, 26 patients with partial and 16 patients with complete intestinal obstructions, were treated over 7 years. Although 24 patients have not received any medications two patients with partial obstructions received flaccid paralyzing agent before referral. However, 12 of 16 patients with complete obstruction received spastic paralyzing agent, and the remaining patients received flaccid paralyzing agent before referral. Paralyzing agents, especially those causing spastic paralysis, should be avoided in patients with abdominal symptoms presumed to be related to ascariasis because of the risk of causing complete obstruction and making surgery more complex.

A simple diagnostic technique was developed to improve the estimated prevalence of tapeworms on farms, by examining post-deworming fecal samples. All horses (n=162) on one farm were dewormed with a triple dose of pyrantel pamoate a and a fecal sample was collected before deworming and 24 hours after deworming. The results showed that the Cornell-Wisconsin centrifugal fecal floatation technique on pre-deworming fecal samples had a 32% sensitivity and 98% specificity when compared to the same technique on post-deworming fecal samples. One barn of horses (n=24) had fecals collected at 17, 24, 39 and 48 hours to determine the optimum time to collect fecals after deworming. The results suggested that the optimum time to collect fecals was 24 hours post-deworming.

The prevalence of benzimidazole-resistant small strongyles was determined in a survey, conducted on 14 thoroughbred studs, which compared the faecal egg counts of groups of horses before and after treatment with the recommended doses of cambendazole (20 mg kg −1 b.w.) or febantel (6 mg kg −1 b.w.). Benzimidazole-resistant cyathostomes were found on all farms examined. Pyrantel pamoate (19 mg kg −1 b.w.), oxibendazole (10 mg kg −1 b.w.) and ivermectin (0.2 mg kg −1 b.w.) reduced the strongyle egg counts on these studs by 97–100% at 2 weeks post-treatment. However, 6 weeks after dosing the reduction of the strongyle egg output had decreased to an average of 67.8% (8.7–97.1%) with pyrantel pamoate and 51.2% (0–95.8%) with oxibendazole, whereas ivermectin still suppressed the egg counts by 98.2% (95–100%).

This article discusses strongyloidiasis, hookworm infection, trichostrongyliasis, ascariasis, trichuriasis (whipworm infection), and enterobiasis (pinworm infection). For each infection, the author describes the organism, the epidemiology and geographic distribution, symptomatology and pathogenesis, and diagnosis and treatment.

4 amebicides (chloroquine diphosphate, diiodohydroxyquin, iodochlorohydroxyquin and dehydroemetine) and 6 anthelmintics (bephenium hydroxynaphthoate, 4-hexylresorcinol, mebendazole, niclosamide, pyrantel pamoate and pyrvinium pamoate) were tested for mutagenicity in the Salmonella typhimurium microsomal test system. Frameshift mutations were induced by dehydroemetine and niclosamide following activation by microsomal enzymes, while pyrvinium pamoate induced both frameshift and base-pair substitution mutations with or without metabolic activation. The urine of mice treated with dehydroemetine or pyrvinium pamoate showed no mutagenic activity. However, urine obtained from mice treated with niclosamide was mutagenic in strains TA98 and TA1538. The fluctuation assay showed chloroquine diphosphate to be mutagenic in TA1537, a strain which detects frameshift mutations.

Several anthelmintic drugs that are used routinely in oxyuriasis therapy were analyzed for genotoxicity in a diploid mitotic recombination and gene conversion assay (strain D5 of Saccharomyces cerevisiae), and in a haploid yeast reversion assay (strain XV185-14C). Piperazine citrate, piperazine adipate, mebendazole and thiabendazole did not appear to be genotoxic in either yeast strain. Pyrvinium pamoate induced the reversion of the missense, nonsense and frameshift alleles in strain XV185-14C, whereas pyrantel pamoate induced only the reversion of the frameshift allele. Pyrvinium pamoate was recombinogenic in strain D5, and there is an indication that pyrantel pamoate, at the lowest dose that was tested, might induce gene conversion or aneuploidy.

A parasitological survey of 271 Malay school children aged 7–13 years (118 males and153 females) from the rural areas revealed that 86·3% of the children were infected with one or more of the intestinal parasites, the most common parasite being Trichuris trichiura (74·2%) followed by Ascaris lumbricoides (41·7%), hookworm (28·0%), Entamoeba coli (8·9%) and Giardia lamblia (8·5%). The infection rate for males (87·3%) and females (85·6%) is similar. The distribution of the parasitic infection with regard to age and sex for the individual species of parasite is discussed. Some of the positive cases were treated with a single dose of oxantel-pyrantel pamoate (15 mg/kg body weight). Cure rates of 90·6, 60·3 and 53·8% were achieved against Ascaris, Trichuris and hookworm. The egg reduction was 97·8, 84·7 and 77·6% for Ascaris, Trichuris and hookworm, respectively.