Higher Egg Counts Research Articles

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Five healthy, vigorous cultivars of sweet potato [Ipomoea batatas (L.) Lam] were cultivated under root-knot nematode Meloidogyne incognita challenge to distinguish levels of resistance to infection. Roots and soil samples were collected 84 days’ post-infection and evaluated for specific host responses to nematode infection by visual screening analysis and quantitative assessments of symptoms of infection. Resistant control cultivar Nugget showed the highest degree of resistance manifested in lower necrosis and galling, high fresh root weights and low nematode and egg counts. Necrosis and galling scores were highest in susceptible cultivars Georgia Jet and DMO1 where extensive root cracking was observed in Georgia Jet, and storage root development was severely restricted in DMO1 which also produced the highest egg counts. TUO2 and Whatley Loretan were considered intermediately resistant based on egg counts and necrosis and galling. Our results suggest that genotypic differences between cultivars were apparent in multiple host responses to root-knot nematode infection. We have also provided initial evidence to support the identification of newly developed sweet potato cultivars with intermediate resistance to root-knot nematodes. Key words: Plant-parasitic nematodes, host plant resistance, Ipomoea batatas, Meloidogyne incognita

Distribution Pattern of Human Urinary Schistosomiasis in Kwara State, Nigeria

Human urinary schistosomiasis is a severe parasitic infectious disease in many rural communities in tropical Africa. The status of infection in Kwara State is inadequately documented. We, therefore, investigated distribution pattern of infection amongst school-aged children in the three Senatorial Districts of the state. Of 3757 urine samples examined, 670 (17.8%) were infected with 8.9% in Central, 13.5% in South and 28.7% in the North Senatorial districts. The overall geometric mean intensity and mean population egg load were 347.3 and 61.9 eggs per 10 mL urine respectively. Generally, infection is age and sex dependent (p<0.05). Males had significantly higher prevalence and intensity of infections than the female (20.6%, 361 eggs/10 mL of urine vs. 14.3%, 340 eggs/10 mL of urine; p<0.0001). A high eggcounts of 412.25 eggs/10 mL urine was recorded among 16-20 years age group in Kwara central. In this study, 27.2 and 10.7% were moderately and heavily infected respectively. There is a significant association between intensity of infection and prevalence of haematuria and proteinuria among the infected population (p<0.0001). Our findings show that urinary schistosomiasis is endemic among kwaran schoolchildren and further study is recommended to reveal the essentials attributable risk factors of infection in the endemic communities.

Epidemiology and effect of gastrointestinal nematodes on dairy goats in Argentina.

The aim of this work was to study the epidemiology and harmful effects of gastrointestinal nematodes (GINs) on dairy goats maintained in an intensive system. Two groups of goats were studied: untreated group (UG) (subdivided into UGjun goats that kidded in June, and UGjul goats that kidded in July) and treated group (TG) (with no subgroups, treated with monepantel: 3.75 mg/kg, orally, monthly). Eggs per gram (epg) in faeces were counted, faecal culture was performed to differentiate nematode genera and milk production was measured. Differences between groups were compared using least squares means analysis of variance (milk production and milking period length) and Kruskal–Wallis test (faecal egg counts). Nematode infection was moderate, with Haemonchus and Trichostrongylus being the dominant genera; the faecal egg counts reached the level of 2000 only once throughout the study. Goats that kidded in June had higher egg count after parturition (UGjun = 1564 epg), with significant differences (p < 0.04) from those that still had not kidded (UGjul = 962 epg). Over the entire trial period, the mean total milk production of TG (399.5 L ± 34.0 L) was significantly higher (p < 0.05) than that of UG (281.6 L ± 37.5 L), representing an increase of 41.8% in total milk yield. The results of this study show a post-partum peak in egg count and a negative effect of GINs on milk yield, even with moderate infections.

Environmental Parasitism Risk and Host Infection Status Affect Patch Use in Foraging Wild Mice

AbstractForaging host individuals can defend against fecal–orally transmitted parasites by avoiding feces‐contaminated patches, which has been widely documented among ungulates. However, it remains unclear whether smaller‐sized hosts (e.g., mice), with their high metabolism and constant needs for energy acquisition, can afford the same behavioral strategy. In this study, we used laboratory and field experiments to test whether feces‐contaminated patches are avoided by the Taiwan field mice Apodemus semotus. In the laboratory experiment, wild‐caught mice whose parasitic infection was not manipulated were given two options to forage from feces‐contaminated and uncontaminated patches. These naturally infected mice spent less time in feces‐contaminated than uncontaminated patches. In the field experiment, we reduced gastrointestinal parasite load of randomly chosen mice via anthelmintic treatment. Whereas the untreated mice did not discriminate among food patches with different levels of parasitism risk (i.e., high‐ or low‐risk patches containing conspecific feces of high or low parasite egg counts, no‐feces patches containing no feces), the treated mice spent less time in feces‐contaminated patches than in no‐feces patches. Similar to the larger‐sized ungulates, we demonstrated here that small mammals can also exhibit fecal‐avoidance foraging. Furthermore, such behavior may be influenced by both environmental parasitism risk and host infection status, which has implications in host–parasite transmission dynamics, namely the selective use of uncontaminated patches by the less‐infected (treated) mice may drive parasites to aggregate within the infected portion of a host population.

Percutaneous Ultrasound‐guided Cholecystocentesis and Bile Analysis for the Detection ofPlatynosomumspp.‐Induced Cholangitis in Cats

BackgroundExamination of bile could be useful to diagnose Platynosomum spp.‐induced cholangitis in cats. Obtaining bile via percutaneous ultrasound‐guided cholecystocentesis (PUC) is possible but raises safety concerns in cats with severe cholecystitis.ObjectivesThe objectives of this study were to investigate the use of PUC to collect bile samples from cats with known platynosomosis and to determine if bile analysis could be a diagnostic test.AnimalsTwenty‐seven free‐roaming cats positive for Platynosomum spp. eggs via fecal examination.MethodsIn this prospective study, fecal egg counts were performed by double centrifugation with Sheather's solution. Bile was collected using PUC from anesthetized cats. Egg counts in bile were performed with a stereoscope. Euthanasia and postmortem examination were performed immediately after PUC.ResultsAll cats had ultrasound (US) evidence of cholangitis or cholecystitis. Thirty‐nine PUCs were performed with 14 cats having 2 PUCs 12 or 24 days apart. Postmortem examinations showed no overt gallbladder damage or leakage but fresh blood was noted in the gallbladder lumen of 3 cats. Median Platynosomum spp. egg counts were higher in bile (1450 eggs/mL; IQR, 400; 5138 eggs/mL) as compared to feces (46 eggs/mL; IQR, 10; 107 eggs/mL) (P < .001).Conclusion and Clinical ImportanceBile egg count analysis is an alternative method with higher egg counts as compared to fecal egg count analysis for the diagnosis of platynosomosis. Obtaining bile via US guidance is technically feasible and safe in cats with cholangitis/cholecystitis. Cholecystocentesis and bile analysis are especially relevant for those cats with chronic cholangitis/cholecystitis and negative fecal egg counts for Platynosomum.

It's time to dispel the myth of "asymptomatic" schistosomiasis.

It's time to dispel the myth of "asymptomatic" schistosomiasis.

COMPARISON AMONG THREE TECHNIQUES IN THE PARASITOLOGICAL DIAGNOSIS OF Fasciola hepatica IN CATTLE

Helminthosis are relevant because they are responsible by substantial economic losses. Many techniques have been developed to facilitate parasitological diagnosis and comparisons among these techniques are essential. The present work aimed a comparison among three techniques of quantitative sedimentation for parasitological diagnosis of Fasciola hepatica in cattle. The modified sedimentation techniques of Dennis, Stone &amp; Swanson (DSS), Girão and Ueno (quatro tamises - QT; four sieves) and Foreyt were compared using analysis of variance, linear regression and correlation tests. Evaluations of sensitivity, specificity and agreement were performed using the kappa test. It was found that the modified DSS technique had a high mean egg count and high sensitivity (p&lt;0.01) (48.60%). The three techniques showed a specificity of 100%. There was no correlation among the values of egg count obtained by the three techniques, and significant coefficients were not observed by regression analysis. The egg count results of F. hepatica obtained by the techniques of quatro tamises and Foreyt showed excellent concordance by the kappa test. The modified DSS technique appeared to be the most effective for F. hepatica diagnosis in cattle (p&lt;0.01).

RELACIÓN ENTRE LA CONDICIÓN CORPORAL Y EL NIVEL DE INFESTACIÓN PARASITARIA EN BOVINOS A PASTOREO COMO CRITERIO PARA EL TRATAMIENTO ANTIHELMÍNTICO SELECTIVO.

The aim of this study was to evaluate the relationship between the level of Strongyletype parasite infestation and body condition in Criollo Rio Limon (n=42), Bos taurus (n=54) and Bos indicus (n=11). The cattle belonged to two farms at Pedraza municipality in Barinas State (Venezuela). Fecal samples were analyzed by the quantitative McMaster technique using saturated saline solution. Body condition score (BCS) was evaluated using a scale of 1 to 5 (1 = thin, 5 = obese) where 2.5 was the cut-off point. The animals were classified as resilient (BCS&gt;2.5 and high egg counts per gram of feces [&gt;800]), resistant (BCS&gt;2.5 and null, mild or moderate parasite burden), sensitive (BCS&lt;2.5, high parasite burden), and false parasite problem (BCS&lt;2.5 and low or no parasite burden). The Criollo Río Limón was associated with resilient and resistant categories, the Bos taurus to the sensitive and false parasite problem categories, and Bos indicus to the resistant category. The relationship between body condition and level of Strongyle-type parasite infestation allows an efficient and rapid identification of the fraction of cattle requiring treatment with anthelmintics.

Prevalence of gastrointestinal helminths and anthelmintic resistance on small-scale farms in Gauteng Province, South Africa

The present study was conducted to determine the prevalence and distribution of gastrointestinal helminths, to detect the presence of anthelmintic resistance in livestock from small-scale farms and to determine the level of helminthosis awareness among small-scale farmers in Gauteng Province, South Africa. Blood and faecal samples were collected from cattle (n = 314), sheep (n = 256) and goats (n = 311). Faecal egg counts and cultures were done, helminth genera identified and packed cell volume was assessed to detect anaemia. A faecal egg count reduction test was used to determine anthelmintic resistance against albendazole (7.5mg/kg), levamisole (5mg/kg) and ivermectin (0.2mg/kg) on five small ruminant farms. A high prevalence of both nematodes and trematodes was observed; however, only 1% of cattle had high nematode egg counts compared to goats (30%) and sheep (32%). Only 5% of the animals were anaemic. Haemonchus and Calicophoron were the most dominant helminth genera in the studied ruminants. Anthelmintic resistance was detected against the three tested drugs on all the screened farms, except against albendazole and levamisole in sheep from Hammanskraal and Nigel, respectively. About 88% of interviewed farmers were aware of veterinary helminthosis, 67% treated against helminths and 83% provided their livestock with nutritional supplements. This study showed that a high prevalence of helminthosis and anthelmintic resistance does occur in the study area, thus relevant strategic interventions are recommended.

Factors influencing the magnitude of strongyle egg-shedding in horses

simultaneously at frequent intervals is still common in Finland, even though horse practitioners are now promoting the use of targeted selective treatment. In order to evaluate selective therapy as an option to reduce anthelmintic use we conducted a study on ten stables. Objectives: 1. To estimate parasite loads of individual horses 2. To analyse risk factors for high egg counts 3. To observe the effects of different anthelmintics to the individual parasite loads. One to eight fecal samples per horse were collected from 215 (86 geldings, 100 mares, 24 stallions) horses (mean age 9.1 yrs, min 0 and max 29) from ten stables in Finland during a one-year study period. The samples were analysed by modified McMaster-technique by the Finnish Food Safety Authority (Evira). Antiparasitic treatment history of each horse was collected by a questionnaire. Majority of the adult horses maintained low epg-values ( 20 years). Majority of the adult horses are able to maintain low epgvalues and therefore frequent treatments with anthelmintics to all horses should be discouraged. Horses should be sampled and treated based on individual risk factors and epg-values. Further analysis of the data will bring more information on how the risk of high epg-count is affected by grazing, season and treatment intervals.

Field Evaluation of a Coproantigen Detection Test for Fascioliasis Diagnosis and Surveillance in Human Hyperendemic Areas of Andean Countries

BackgroundEmergence of human fascioliasis prompted a worldwide control initiative including a pilot study in a few countries. Two hyperendemic areas were chosen: Huacullani, Northern Altiplano, Bolivia, representing the Altiplanic transmission pattern with high prevalences and intensities; Cajamarca valley, Peru, representing the valley pattern with high prevalences but low intensities. Coprological sample collection, transport and study procedures were analyzed to improve individual diagnosis and subsequent treatments and surveillance activities. Therefore, a coproantigen-detection technique (MM3-COPRO ELISA) was evaluated, using classical techniques for egg detection for comparison.Methodology and FindingsA total of 436 and 362 stool samples from schoolchildren of Huacullani and Cajamarca, respectively, were used. Positive samples from Huacullani were 24.77% using the MM3-COPRO technique, and 21.56% using Kato-Katz. Positive samples from Cajamarca were 11.05% using MM3-COPRO, and 5.24% using rapid sedimentation and Kato-Katz. In Huacullani, using Kato-Katz as gold standard, sensitivity and specificity were 94.68% and 98.48%, respectively, and using Kato-Katz and COPRO-ELISA test together, they were 95.68% and 100%. In Cajamarca, using rapid sedimentation and Kato-Katz together, results were 94.73% and 93.58%, and using rapid sedimentation, Kato-Katz and copro-ELISA together, they were 97.56% and 100%, respectively. There was no correlation between coproantigen detection by optical density (OD) and infection intensity by eggs per gram of feces (epg) in Cajamarca low burden cases (<400 epg), nor in Huacullani high burden cases (≥400 epg), although there was in Huacullani low burden cases (<400 epg). Six cases of egg emission appeared negative by MM3-COPRO, including one with a high egg count (1248 epg).ConclusionsThe coproantigen-detection test allows for high sensitivity and specificity, fast large mass screening capacity, detection in the chronic phase, early detection of treatment failure or reinfection in post-treated subjects, and usefulness in surveillance programs. However, this technique falls short when evaluating the fluke burden on its own.

Seasonal and monthly prevalence pattern of fasciolosis in buffaloes and its relation to some climatic factors in northeastern areas of Punjab, Pakistan

Summary A study was conducted in the northeastern areas of Punjab province (Pakistan) to analyse the monthly and seasonal pattern of fasciolosis in buffaloes and its relation to some climatic factors (temperature, humidity, rainfall and pan-evaporation) was also worked out. The faecal samples of buffaloes were collected from April 2003 to March 2005 on a monthly basis from randomly selected areas and analysed for the presence of Fasciola egg. From 7200 samples, 1058 (14.69%) were found positive. Seasonal data showed the highest prevalence and egg count (EPG) in autumn and the lowest in spring. Monthly results showed the highest prevalence in September (32.33%) and the lowest in May (4.83%), while mean EPG was highest in October (567 ± 95.5) and the lowest in June (3.2 ± 0.48). Statistically, significant difference (P<0.05) was noted within seasonal and monthly prevalences. Impact of humidity was found significant (P<0.05) on disease as compared to other climatic factors.

Correlates of resistance to gastrointestinal nematode infection in Nigerian West African dwarf sheep

ObjectiveTo investigate correlates of resistance to GI nematode infection in Nigerian West African dwarf (WAD) sheep. MethodsThirty three sheep were randomly assigned to two groups, A (n=27) which were used for experimental infections, and B (n=6) which served as uninfected control. Each infected animal received weekly escalating infections with infective larvae (60%Haemonchus contortus (H. contortus) and 40%Trichostrongylus colubriformis (T. colubriformis) for 4 weeks. The responses of all the infected and control sheep were assessed by faecal egg count (FEC), worm burden (Wb), packed cell volume (PCV), body weight (Bwt), and body condition score (BCS). On the basis of their individual faecal egg output, Lambs in group A with epg ≤1 000 on any sampling day were classified as low faecal egg count (LFEC) phenotype (n = 16), those with epg between 1 000 and 10 000 as intermediate (n=5) and lambs with epg > 10 000 as high feacal egg count (HFEC) phenotype (n=6). ResultsThe difference between the FEC classes was highly significant (P=0.001). The BCS and weight gained at the end of the experiment by the control and LFEC sheep was significantly higher (P≤0.05) than those of the intermediate and HFEC phenotypes. There was a significant and negative correlation between the parasitological measures and the trio of BCS, PCV and Bwt of sheep. ConclusionThe result of the study indicated that the FEC, weight gain, PCV, and BCS are correlates and potential selection criteria of GI nematode resistant WAD sheep.

The sensitivity of direct faecal examination, direct faecal flotation, modified centrifugal faecal flotation and centrifugal sedimentation/flotation in the diagnosis of canine spirocercosis

Several faecal examination techniques have shown variable sensitivity in demonstrating Spirocerca lupi (S. lupi) eggs. The objective of this study was to determine which faecal examination technique, including a novel modified centrifugal flotation technique, was most sensitive to diagnose spirocercosis. Ten coproscopic examinations were performed on faeces collected from 33 dogs confirmed endoscopically to have spirocercosis. The tests included a direct faecal examination, a faecal sedimentation/flotation test, 4 direct faecal flotations and 4 modified faecal centrifugal flotations. These latter 2 flotation tests utilised 4 different faecal flotation solutions: NaNO3 (SG 1.22), MgSO4 (SG 1.29), ZnSO4 (SG 1.30) and sugar (SG 1.27). The sensitivity of the tests ranged between 42% and 67%, with the NaNO3 solution showing the highest sensitivity in both the direct and modified-centrifugal flotations. The modified NaNO3 centrifugal method ranked 1st with the highest mean egg count (45.24 +/- 83), and was superior (i.e. higher egg count) and significantly different (P < 0.05) compared with the routine saturated sugar, ZnSO4 and MgSO4 flotation methods. The routine NaNO3 flotation method was also superior and significantly different (P < 0.05) compared with the routine ZnSO4 and MgSO4 flotation methods. Fifteen per cent (n = 5) of dogs had neoplastic oesophageal nodules and a further 18% (n = 6) had both neoplastic and non-neoplastic nodules. S. lupi eggs were demonstrated in 40% of dogs with neoplastic nodules only and 72.9% of the dogs with non-neoplastic nodules. The mean egg count in the non-neoplastic group (61) was statistically greater (P = 0.02) than that of the neoplastic group (1). The results show that faecal examination using a NaNO3 solution is the most sensitive in the diagnosis of spirocercosis. The modified centrifugal flotation faecal method using this solution has the highest egg count. The study also found that dogs with neoplastic nodules shed significantly fewer eggs than dogs with non-neoplastic nodules.

The effect of iron and multi-micronutrient supplementation on Ascaris lumbricoides reinfection among Zambian schoolchildren

A randomised, placebo-controlled, double-blind trial was conducted among schoolchildren in Chawama, Lusaka, Zambia, to determine the effect of iron and multi-micronutrients on reinfection with Ascaris lumbricoides. Supplementation was given on every school day for 10 months. Baseline A. lumbricoides prevalence and geometric mean intensity among positives were 43.4% and 2526 eggs per gram (epg) faeces, respectively. Serum ferritin <12microg/l was associated with higher egg counts than serum ferritin >or=12microg/l (4728 vs. 2036epg, P=0.033). Of 406 children recruited, 378 (93.1%) were examined at baseline and all infected children were treated and cure ascertained. The mean number of tablets taken per week was 2.5, giving 50% compliance. At six months 283 (74.9%) children complied, and reinfection intensities in those receiving iron were lower than in those receiving placebo (1600 vs. 3085epg, P=0.056). This effect disappeared at 10 months, where 215 (56.9%) complied. Iron had no effect on A. lumbricoides reinfection rates and multi-micronutrients had no effect on reinfection rates or intensities. Iron appears to affect reinfection intensity with A. lumbricoides, but further investigations are required to confirm this effect and elucidate the mechanisms involved.

A Point Prevalence Study of Gastrointestinal Parasites in Burchell\'s Zebra (&lt;i&gt;Equus Burchelli Antiquorum&lt;/i&gt;) at Lewa Downs Ranch, Isiolo District Kenya

Burchell's Zebra ( Equus Burchelli Antiquorum ) were sampled for gastrointestinal parasites at the Lewa Downs Game Ranch in Isiolo District between 4/7/95 and 11/7/95. The stomach, small intestines and abdominal cavity were searched for parasites. The parasites were identified to genus level but in some cases to species level. Feacal egg counts, hematology and serum biochemistry screening were also performed. All animals were infested with at least three genera of gastrointestinal parasites including at least one nematode genus. A total of nine genera were recovered representing eight families. These included six nematode families, Strongylidae, Strongylinae, Atractidae, Oxyuridae, Spiruridae, and Setaridae one cestode family, Anoplocephalidae and one family of the larvae of Gasterophilus bot flies, Gastrophilidae. The most prevalent families were Atracidae (100%) and Strongylinae (80%). The mean total worm burden was 78,764. The average of individual genera varied from 0-77,890worms. The average worm burdens were higher in females than in males. In comparing the mean total egg counts, there were generally higher egg counts in animals with higher worm burdens. Hematology results were within baseline values for Burchell's zebra. Blood biochemistry showed high levels of Alkaline Phosphatase, Creatine Kinase, Lactase dehydrogenase and Aspartate transaminase was partly attributed to exertion before death. The Kenya Veterinarian Vol. 25 2002: pp. 44-49

41 TRANSMISSION OF A PARASITE-RESISTANT PHENOTYPE FROM A DONOR RAM TO ITS CLONED OFFSPRING

A 9-year-old parasite-resistant superfine Merino ram was cloned to study the inherited phenotype in cloned offspring. This donor ram was &amp;gt;3 standard deviations below the mean for internal parasite fecal egg counts in a 10 000 sheep flock. Two viable rams were produced from 3 days of NT. Their health status was studied from birth to maturity and their fertility and progeny via an AI program. Their mucosal immune system was indirectly assessed through their ability to cope with high internal parasite challenges. Oocytes were extracted from abattoir ovaries in late autumn. Serum-starved fibroblasts were combined with enucleated oocytes and fused; the couplets wereactivated at 25–26 h postmaturation with ionomycin and then DMAP. Embryos were cultured in a 2-stage bovine embryo culture medium (Cook) for 6 days in 5% oxygen. From 3 days of NT, all 37 embryos reaching blastocyst or compact morula stages were transferred into 14 ewes. At Day 30, 6/14 ewes were pregnant with single fetuses and 1 fetus died by Day 60. Each of the 5 lambs had breathing difficulties at birth and 3 died. For 2 weeks prior to term, maternal serum levels (collected every other day) of progesterone and estradiol were not different between viable and non-viable pregnancies. In the 2 viable pregnancies, cortisol levels peaked (&amp;gt;10 ng mL–1), then dropped sharply (&amp;lt;2 ng mL–1 for 4 days), and then rose to the time of birth (&amp;gt;7 ng mL–1). This cortisol profile may help explain why the 2 viable lambs acquired sufficient lung capacity by the time of birth to survive. Samples for fecal egg counts and complete blood counts were collected monthly for 12 months on the 2 surviving ram lambs. Fecal egg counts were 2–5 times higher than for 2 control animals, with peak counts reaching 3000–4000 eggs per gram. Larval culture showed the eggs were predominantly Hemonchus. Clone 2 had consistently higher egg counts than clone 1. Both clones had persistent loose feces for the first 6 months and Clone 2 continues to have diarrhea. Red blood cell counts were consistently low normal (8–11 million/�L). White cell counts were normal, other than when high counts (16 000 per �L) corresponded with high fecal egg counts. Body weight, wool quantity, and fiber diameter at 1 year of age were slightly different between clones (59 kg; 5.3 kg; 16.4 �m vs. 54 kg; 4 kg; 16 �m, respectively). Scrotal circumference was larger for clone 1 than for clone 2 (29 cm vs. 24.5 cm). Semen from the rams was cryopreserved for use in an AI program (50 ewes per sire) to progeny-test lambs produced by the 2 rams, the original donor ram, and a link ram, with lambing due in October 06. Overall, clone 1 has remained consistently healthier than clone 2. High fecal egg counts indicated significant internal parasite challenge during their first year of life, which resulted in elevated white blood cell responses. The obvious clinical effect of high egg counts was diarrhea, which may indicate a beneficial response to parasite infection. Continued studies will further document their parasite resistance, immune responses, and progeny characteristics.

Evaluation of PCR based coprodiagnosis of human opisthorchiasis

In this study, a recently developed PCR test for the detection of Opisthorchis viverrini in human faecal samples was evaluated using two parasitological methods as references. During a survey of foodborne trematodes (FBT) in the Vientiane Province, Lao PDR, 85 samples were collected and evaluated for FBT eggs by the Kato Katz (KK) technique, the formalin ethyl acetate concentration technique (FECT) and a PCR analysis for the distinction between O. viverrini and other FBT. The two parasitological methods did not differ in the ability of detecting FBT eggs, and a single KK reading was characterized by a sensitivity of 85% when compared to two FECT readings. The PCR tested positive only in cases where eggs had been demonstrated by parasitological examination. However, the PCR tested negative in some samples with very high egg counts. Demonstrating a PCR sensitivity of approximately 50% in samples with faecal egg counts > 1000, the previously reported PCR sensitivity based on in vitro studies was not supported. It is believed that technical problems rather than diagnostic reference related issues were responsible for the relatively low PCR performance. Further studies should aim at optimizing DNA extraction and amplification, and future PCR evaluation should include specificity control such as the scanning electron microscopy of eggs in test samples or the expulsion of adult trematodes from PCR tested individuals.

Variation among faecal egg counts following natural nematode infection in Scottish Blackface lambs

Faecal egg counts were examined in 2 flocks of naturally infected Scottish Blackface sheep in southern and central Scotland. The distribution of mean counts was right skewed and similar to a gamma distribution. The counts varied with month, with mean counts rising from May to July, then falling but rising again in October, although data within each year did not always show such a clear pattern. There was no significant difference in mean egg count between the 2 farms examined. The distribution of egg count variances was also right skewed and conformed to a gamma distribution. There was a strong relationship between the mean and the variance for each population, implying that variation among populations in variances largely mirrored variation in mean egg counts. Populations with high mean egg counts and variances did not necessarily have more adult nematodes but had a greater number of adult nematodes from species other than Teladorsagia circumcincta, particularly Cooperia spp., Trichostrongylus axei and Trichostrongylus vitrinus. The contribution of different parasite species to the egg count explains the relatively poor and inconsistent fit of the negative binomial distribution to faecal egg counts in lambs.

Investigations on the seasonal patterns of strongyle infections in grazing lambs, and the occurrence of anthelmintic resistance on sheep and goat farms in western Anatolia, Turkey

The seasonal patterns of strongyle infections in untreated, weaned lambs were determined on four governmental farms during a grazing season. In three farms, the infection level (predominantly Teladorsagia spp. and Trichostrongylus spp.) measured by egg counts or worm burdens remained low throughout the study; higher egg counts mainly caused by Haemonchus contortus were transiently recorded on the fourth farm. Significant body weight gains were observed in all groups, but they varied between farms irrespective of the level of strongyle infections, suggesting that the economic effectiveness of anthelmintic treatments of weaned lambs is doubtful under the extensive grazing conditions and the hot, dry climate in the region. In the second part of the study, faecal egg count reduction tests were performed for albendazole, thiabendazole, tetramisole and ivermectin on 12 sheep and goat farms to provide first information on anthelmintic resistance in trichostrongyles of small ruminants in Turkey. There was no hint of benzimidazole resistance, and unequivocal evidence of ivermectin resistance was missing. In contrast, tetramisole resistance was detected on one sheep farm.