Helminths In Sheep Research Articles

O-153 Prevalence of gastrointestinal helminths in sheep, as assessed by microscopy and droplet digital PCR

O-153 Prevalence of gastrointestinal helminths in sheep, as assessed by microscopy and droplet digital PCR

Prevalence of gastrointestinal helminths of small ruminants in and around Kulubi town, Meta Woreda of East Haraghe Zone, Oromia, Ethiopia

A cross-sectional study was conducted in sheep and goats that were kept under an extensive management system in Kulubi town, Meta Woreda of East Haraghe Zone, Oromia, Ethiopia, from November 2018 to May 2019 to determine the prevalence and associated risk factors of gastrointestinal helminths (GIT). A total of 384 randomly sampled sheep and goats (198 sheep and 186 goats) were subjected to coprological examination using simple floatation and sedimentation techniques. Based on this, the overall prevalence of GIT helminths in sheep and goats was 58.9% (226/384). Out of the total sampled animals, the prevalence of 59.09% (117/198) and 58.6% (109/186) were recorded in sheep and goats, respectively. Based on a coprological examination, in the study area, the prevalence of 20.2%, 10.6%, 10.6%, 8.08%, 6.58%, and 3.03% accounted for Strongyle, Trichostrongylus, mixed-type, Trichuris, Strongyloides, and Fasciola eggs detected in sheep and 18.8%, 8.6%, 8.06%, 8.06%, 6.45%, 5.4%, and 3.23% accounted for Strongyle, Trichostrongylus, Fasciola, Paramphistomum, Trichuris, Nematodirus, and Strongyloides eggs were detected in goats. There was no significant difference (p > 0.05) in the prevalence of the parasites between different species and the sex of the animals. However, the age and body condition score of the animals has shown a statistically significant difference (p < 0.05). In general, some amount of high prevalence of helminth parasites was observed in the study area, which implies helminths are the major constraints for the productivity of small ruminants. Therefore, economically feasible, effective management, and strategic de-worming of animals should be implemented for the prevention and control of the disease.

Эспарцет (Onobrychis Adans .): выгодная культура в органическом лугопастбищном хозяйстве (обзор )

Perennial legumes are the most beneficial crops in the organic grassland farming. These crops include sainfoin, which should take its rightful place in forage lands, especially in modern conditions of increasing aridity. Three species are cultivated in Russia: Onobrychis viciifolia Scop., O. arenaria (Kit.) DC and O. transcaucasica Grossh. The cultivation of sainfoin is of great ecological importance due to its special ecological properties and chemical composition. It has a deep and highly branched root system, capable of absorbing nutrients from deep soil layers. The root system of sainfoin absorbs minerals from hard-to-reach soil compounds, so it is little responsive to fertilisation, and can be successfully used in organic grassland farming. Unlike other leguminous grasses, with the exception of the birdsfoot trefoil, sainfoin does not cause bloat in ruminants. This is due to the presence of condensed tannins (CTs) in the plant in the amount of 30–80 g per 1 kg of dry matter. СТs increase the amount of non-degradable protein in the rumen, which prevents bloat in ruminants, reduces methane emissions and nitrogen compounds in urine, which in turn reduces the impact of greenhouse gases on the heat balance of the Earth. СТs have shown in vivo anti-parasitic activity against helminths in sheep and goats, improving feed nutrient utilisation and increasing animal productivity. Sainfoin fixes atmospheric nitrogen in an amount up to 150 kg/ha and does not require the application of nitrogen fertilisers, which can pollute groundwater and atmospheric air. Enriching the soil with nitrogen and other nutrients due to their biological accumulation in the upper soil layer, sainfoin contributes to soil fertility. sainfoin provides yields from 4 to 7 t/ha of dry matter with a productive longevity of herbage for 4–7 years reducing the cost of reseeding.

Studija helminta u ovaca u Laghouat regiji u južnom Alžiru

The objective of this study was to detect helminths in sheep on farms in three different zones of the Laghouat region, and to examine relationships between the prevalence of these parasites and the factors of age, sex, and area. The study was carried out over a period of four months (March to June 2019) on 77 faecal samples taken from 77 sheep. For this purpose, we used both a qualitative technique (flotation) and a quantitative technique (Mac Master). These two techniques allowed us to isolate helminths and determine the degree of infestation of sheep in the steppe region, specifically the Laghouat region. The results showed that the sheep flock studied overall was negative, with the exception of eight subjects infected with Nematodirus or Strongyloides at a rate of 7.49% each. The helminth parasite prevalence was 10.40%. Statistical analysis of the influence of specific factors revealed no significant effect (P˃0.05) for sex, though the effects of age and area were significant (P<0.05). This parasite prevalence must be taken seriously to avoid its detrimental effect on animal health and the zootechnical performance of sheep flocks.

Breed and environmental factors influencing prevalence of helminths in sheep

Gastrointestinal parasites impose severe constraints on sheep production worldwide. lnformation on prevalence of helminthosis in the ovine species could provide a useful guide towards effective control. Investigated in this study was helminthosis prevalence in some Nigerian sheep. The sheep included initial 64 yearlings (12 each of Balami, BL, and Uda, UD, and 20 each of Yankasa, YK and West African Dwarf, WAD, in a sex ratio of 1:1 per breed) and their 156 offspring. Faecal samples were collected from the sheep six-weekly over a period of 3 years and examined for the presence of various helminth species using the modified McMaster technique. Total helminths, Strongyles, Strongyloides, Moniezia, Trichuris and Nematodirus prevalence were 95.9, 87.3, 38.2, 60.6, 45.0 and 46.4%, respectively. Based on prevalence, breeds and seasons ranked (p < 0.05) thus: YK = WAD > BL > UD and late rainy> early rainy> late dry > early dry. Females and older sheep (≥ 4months) had higher (p < 0.05) prevalence than males and lambs (< 4months), respectively. Prevalence increased with decreased body condition score (BCS). Year, birth type and parity did not influence prevalence. It is concluded that there is high prevalence of helminthosis in the study area, with variation between breeds, sex, age groups and seasons. These variations could be exploited through selective breeding and cross breeding to control the disease with or without minimal use of anthelminthics. Les parasites gastro-intestinaux imposent de sévères contraintes à la production ovine dans le monde. Les informations sur la prévalence de l'helminthose chez les ovins pourraient fournir un guide utile pour une lutte efficace. La prévalence de l'helminthose chez certains moutons nigérians a été étudiée dans cette étude. Les moutons comprenaient au départ 64 yearlings (12 chacun de Balami, BL et Uda, UD, et 20 chacun de Yankasa, YK et West AfricanDwarf, WAD, dans un rapport de masculinité de 1 : 1 par race) et leurs 156 descendants. Des échantillons de matières fécales ont été prélevés sur les moutons six fois par semaine sur une période de 3 ans et examinés pour la présence de diverses espèces d'helminthes en utilisant la technique modifiée de McMaster. La prévalence totale des helminthes, Strongyles, Strongyloides, Moniezia, Trichuriset Nematodirus était de 95.9, 87.3, 38.2, 60.6, 45.0 et 46.4%, respectivement. Sur la base de la prévalence, des races et des saisons classées (p <0.05) ainsi : YK = WAD>BL> UD et pluvieux tardif> pluvieux bdafur70@gmail.com 13 précoce> sec tardif> sec tôt. Les femelles et les moutons plus âgés (≥ 4 mois) avaient une prévalence plus élevée (p<0.05) que les mâles et les agneaux (<4 mois), respectivement. Laprévalence augmentait avec la diminution du score de l'état corporel (le 'BCS'). L'année, letype de naissance et la parité n'ont pas influencé la prévalence. Il est conclu qu'il existe uneprévalence élevée d'helminthose dans la zone d'étude, avec des variations entre les races, lesexe, les groupes d'âge et les saisons. Ces variations pourraient être exploitées par unesélection sélective et des croisements pour lutter contre la maladie avec ou sans utilisationminimale d'anthelminthiques.

Epidemiology of Gastrointestinal Helminths of Sheep in Aeolian Plains of Haryana

Epidemiology of Gastrointestinal Helminths of Sheep in Aeolian Plains of Haryana

Evaluación de endoparasiticidas de las moléculas Moxidectina e Ivermectina contra nematodos gastrointestinales de ovinos infectadas naturalmente

Gastrointestinal helminths in sheep are the main factor that interferes in the production and rearing of these animals and if not treated properly, can lead to the development of resistance, resulting in losses to the producer. In this way, the objective of this work is to determine the anthelmintic activity formulations containing moxidectin and ivermectin in sheep naturally infected by gastrointestinal nematodes belonging in Umuarama-PR region, by performing egg count reduction tests by gram of feces (OPG). In two evaluated proprieties tested, the two formulations demonstrated inefficiency in anthelmintic on sheep activity.

Prevalence of gastrointestinal helminths in sheep raised in intermediary geographical region of Paraiba state, Brazil

The objective of this study was to evaluate the prevalence of gastrointestinal nematodes (GIN) of sheep herds from twenty-three sheep farms spread in the Alto Sertão region of Paraíba state, Brazil. Sample size was obtained through a simple random sampling, which was determined from the total amount of sheep head of the microregion. It was collected 262 faecal samples directly from the rectum of the animals, conditioned in polyethylene bags previously identified and kept refrigerated until processing. Faecal egg counting was performed and cultures in pool of each farm were done separately. It was observed a prevalence of GN of 84.7% (222/262) to the evaluated sheep. Furthermore, it was noted the presence of unless one positive animal for helminths in 100.0% of sheep farms. Among the 222 positive animals, 65.3% presented EPG<1000, 15.8% EPG among 1000-2000 and 18.9% presented EPG>2000. Recovered third stage larvae showed that the most prevalent nematode was Haemonchus sp. (79.6%), followed by Trichostrongylus sp. (13.8%), Oesophagostomum sp. (3.6%), Strongyloides sp. (2.4%) e Bunostomum sp. (0.6%). Sheep herd from the Alto Sertão region of Paraíba state presents a high prevalence of GIN.

Statistical models for helminth faecal egg counts in sheep and goats

To address the problem of prevalence of gastrointestinal parasite infections faced by rural livestock farmers in the Free State Province of South Africa, we model the distribution of faecal egg counts of parasitic helminths in sheep and goats. Excess zeroes in the data results in over-dispersion, which we address by fitting Poisson, negative binomial (NB), zero inflated Poisson (ZIP) and zero inflated negative binomial (ZINB). The proposed zero inflated models explicitly isolate unexposed animals within an infected group, making them ideal for selection purposes. Distributions of parasite egg count data in both sheep and goats were zero inflated for all the species except for strongyle egg counts in goats, which fitted negative binomial distribution. Rainfall, season and site were found to be predominantly significant in determining the distribution of parasites among their host. The findings on how the covariance structure relates to the distributional assumptions assist in the formulation of the necessary interventions. For instance in setting strategies to control gastrointestinal parasite infections or in identifying animals with the desired traits. Subsequently improving the livelihood of the rural communities.

Helminth Infections by Coprological Examination in Sheep-Dogs and Their Zoonotic Importance.

This study was conducted to determine the prevalence of gastrointestinal helminths and diagnose the species of important zoonotic helminths in sheep dogs. Firstly, fecal samples were macroscopically examined; subsequently, formalin-ethyl acetate sedimentation and ZnSO4 centrifugal floatation techniques were applied for the examination of helminth eggs. PCR technique was utilized to determine the species of E. granulosus and T. canis in dogs found positive for Taenia spp. and Toxocara spp. Helminth infection was detected in 35.26% of sheep dogs. Taenia spp. was the most common helminth (12.05%), followed by Toxocara spp. (9.38%), Toxascaris leonina (6.25%), and Trichuris spp. (4.2%). The positive results in the E. granulosus and T. canis-specific PCR-based molecular tests were obtained in 14 of the Taenia egg-positive samples and in 5 of the Toxocara egg-positive samples from dogs. This study has suggested that coprophagy and feed raw offal and meat to dogs may be responsible for finding atypical helminth eggs in fecal samples from dogs in the absence of an actual infection. To make the diagnosis of their owned parasites of dogs, E. granulosus and T. canis which have zoonotic importance, feces must be examined by both conventional and copro-PCR techniques. In addition to dogs' feeding habits, other related factors must be taken into account in the epidemiology of helminth infection; thus, precaution and control measures will be more reliable.

Prevalence of gastrointestinal helminths of sheep in Sherpur, Bangladesh

Prevalence of gastrointestinal helminths of sheep in Sherpur, Bangladesh

Coadministration of nematophagous fungi for biological control over gastrointestinal helminths in sheep in the semiarid region of northeastern Brazil

This study aimed to evaluate coadministration of Duddingtonia flagrans and Monacrosporium thaumasium in a sodium alginate matrix for controlling gastrointestinal helminths in young and adult sheep in the semiarid region of northeastern Brazil. An area of 1ha was divided into two paddocks, in which two experimental groups (fungus and control) were formed, each consisting of six adult females and ten young males. In each group, two subgroups were formed in accordance with the animal category (adult or young). In the fungus group, each animal received 3g of pellets containing 0.6g of fungal mycelium, with 0.3g of D. flagrans and 0.3g of M. thaumasium for each 10kg of body weight, in their feed twice a week, for six months. In the control group, each animal received 3g of pellets without fungus for each 10kg of body weight, in their feed twice a week, for six months, serving as a witness group. Reductions in numbers of eggs per gram of feces of 76% among the adult sheep in the fungus group and 83% among the young sheep in the fungus group were observed, in comparison with their respective control subgroups. The groups that received these fungi needed less salvage deworming and presented better packed cell volume percentages, better weight gain and lower levels of L3/kg dry matter in their paddock than the control groups. Thus, it was concluded that coadministration of D. flagrans and M. thaumasium was effective in controlling gastrointestinal helminths of adults and young sheep in the semiarid region of northeastern Brazil.

Seasonal Prevalence of Gastro-Intestinal Helminths of Sheep (Ovis Aries) and Goat (Capra Hircus) with Respect to Age and Gender of Gurez Valley, Kashmir

The present study was carried out with an objective to assess the seasonal dynamics of intestinal helminth parasites in association with age and gender of sheep (Ovis aries) and goat (Capra hircus) in Gurez valley. Out of the total of 123 sheep and 96 goats examined through gut examination during May 2013 - May 2015, 25.20%, 17.07%, 27.64% in sheep and 22.91%, 15.62%, 26.04% in goats was the prevalence of trematodes, cestodes and nematodes respectively. Comparatively goats harbored low infection level as compared to sheep. There was no significant difference (P>0.05) in gastrointestinal parasite infection in Ovis aries and Capra hircus examined. Data showed that infection was moderately positive all year round but highest infection was found in the autumn season. A significant relationship was found between seasons and prevalence of infection (P

Results of limited scale trial of Sulfmonzol 5%

Results of experiments on the use of anthelminthic drug agianst helminths in sheep, goats and cattle reveal that preparation "Sulfmonzol 5%" has relatively higher effectiveness (98.8-100.00%) against helminths eggs in sheep and cattle at day 21 of the trial, while it is highly effective (98.1-100.0%) against goat helminths at day 14 of the trial. DOI: http://dx.doi.org/10.5564/mjas.v11i2.212 Mongolian Journal of Agricultural Sciences Vol.11(2) 2013 pp.30-32

FAUNA OF GASTROINTESTINAL STRONGYLATES OF SHEEP AND GOATS ON THE TERRITORY OF THE CHECHEN REPUBLIC

Abstract . Aim. Livestock is one of the main sources of protein human nutrition. Helminthiases infections are one of the limiting factors in animal husbandry. The most prevalent helminths of sheep and goats OF gastrointestinal tract are Strongylatoses. Studies on helminthiasis are absent during the last twenty years in the Chechen Republic. This paper analyzes the state of nematode infections of cattle in farms and private land plots of the Chechen Republic. The aim of the work is study of Strongylata infections of gastrointestinal tract of sheeps and goats: taxonomic composition, identification of extensiveness and intensity of infestation of strongylate invasions in the Chechen Republic. Material and methods. Tripes, intestines and lungs of 235 sheep 1-2-3-4-5-6-7-8-9-10-11-12-months of age, 1–2 years sheeps, 2–3 years sheeps and older than 3 years sheeps were studied. The follows methods were used: the method of opening full helminthological autopsy by Scryabin, the method of Fulleborn, helminthological research method by Berman-Orlov. Results. Livestock is infected by 14 species of nematodes of the suborder Strongylata, that are parasitic in the gastrointestinal tract. The most common nematodes are of genera Chabertia , Nematodirus , Haemonchus , Trichostrongylus , Ostertagia , Cooperia , Bunostomum . Conclusions. The results will allow to plan the most optimal anthelmintic activities.

Fauna helmintológica de ovinos provenientes da microrregião de Jaboticabal, estado de São Paulo, Brasil

Avaliou-se a prevalência e a contagem parasitária das diferentes espécies de helmintos de ovinos provenientes da microrregião de Jaboticabal, região Noroeste de São Paulo. Para tanto, foram utilizados 66 animais naturalmente infectados, de quatro a 36 meses de idade, criados em regime extensivo. Os resultados necroscópicos revelaram a presença de sete gêneros e 12 espécies, com a seguinte prevalência e a média de parasitismo: Haemonchus contortus: 100,0% (2947,2); Trichostrongylus colubriformis: 90,9% (3048,8); Cooperia curticei: 56,0% (256,5); Oesophagostomum columbianum: 48,4% (36,0); Cooperia punctata: 30,3% (94,5); Trichostrongylus axei: 22,7% (26,5); Strongyloides papillosusi: 19,6% (83,0); Haemonchus contortus (L4): 7,5% (17,2); Cooperia pectinatai: 10,6% (12,9); Trichuris ovis: 10,6% (0,6); Cooperia spatulata 4,5% (0,3); Capillaria bovis: 4,5% (0,1). A carga parasitária média foi de 6.524,7 helmintos por animal. Haemonchus contortus (Adultos e L4) e Trichostrongylus colubriformis corresponderam a 45,4% e 46,7% da carga parasitária média total, respectivamente. Pode-se concluir que as duas espécies de helmintos mais abundantes e importantes da microrregião de Jaboticabal/São Paulo foram Trichostrongylus colubriformis e Haemonchus contortus, sendo que essas duas espécies perfizeram 92,1% da distribuição percentual dos helmintos recolhidos de todos os animais. Tais resultados demonstram a importância em se realizar um monitoramento das contagens de ovos por grama de fezes (OPG) dos rebanhos desta região, quando o método FAMACHA for empregado em uma determinada propriedade, uma vez que este método de controle, geralmente, não permite diagnosticar os danos/sinais clínicos desencadeados nos animais pelo T. colubriformis, em função de essa espécie não possuir hábito de hematofagismo sobre os hospedeiros.

The “BIG FIVE” – A South African perspective on sustainable holistic internal parasite management in sheep and goats

Because we became an unintended world leader in the development of multiple anthelmintic resistance, South Africa has had to find, embrace and implement more sustainable and holistic methods of managing helminths in sheep. The problem has been to wean farmers off a heavy reliance on anthelmintics and to use a wide array of measures that require more management, in the face of inertia and attempts by some unscrupulous drug purveyors to block the needed changes. Packaging the available and proven measures into five practical sections helps to make the change more palatable and attractive to farmers. These sections are termed “The Big Five” and consist of firstly, host resistance and resilience: in the past we have concentrated too much on anthelmintic resistance (AR) and not enough on SR (sheep resistance). The motto must be “Stop Selecting Sissy Sheep!” To achieve this we can apply selection of rams by faecal egg counts (FEC) or FAMACHA, culling of ewes based on targeted selective treatment (TST) results, good nutrition, especially protein and trace elements needed to support immunity, enough exposure to worms for immunity to develop, and control of other diseases. Secondly, reducing parasite load: since the outcome of parasitosis is largely determined by numbers, this needs ongoing attention. This can be achieved by reducing the length of stay in a pasture, reducing the grazing pressure if this is not possible, increasing the time of absence from a pasture, especially at danger times, alternation with non-susceptible grazing species where possible, avoiding worm “hot spots” like grassed pens and leaking water troughs. Thirdly, evaluate pasture factors: the farmer and advisor have to consider the height (length) of grazing as it affects its risk for parasite transfer, the type (pasture species) as it will influence risk, the pasture slope affecting run-off and thus the suitability for larval survival, and the aspect (direction facing) should also be used to assess risk. Fourth, monitoring the situation: farm situations can be assessed by regular (monthly or bimonthly) pooled flock FECs, AR assessments using FEC reduction tests (FECRTs) or other measures, measures using TST like the 5 POINT CHECK, a weather watch to predict conditions favourable for larval development (rain, humidity, temperature) and grazing monitoring to assess developing dangers. Fifth, optimise drugs to be used: drug usage must be rationalised and minimised. Implement TST and TT (targeted treatment); read the label, follow instructions and check the spectrum covered; weigh the sheep, set dose according to the heaviest in the group and check the gun for accuracy and repeatability; target the most vulnerable (lambs and lactating or heavily pregnant ewes) for special attention; do not buy on cost alone and do not formulate (mix) own farm mixtures. By emphasising the “Big Five” we can encourage and enable farmers to implement four or more items in each section, and thus minimise the long-term effects of internal parasites on farm profitability. This approach has assisted with getting farmers to use sustainable, holistic internal parasite management (SHIPM) in sheep flocks. A reminder in the form of a poster to be hung on the wall of the farm office will help encourage continuous implementation.

Prevalence of helminth parasites in sheep (Ovis aries) in Tangail district, Bangladesh

Prevalence of helminths of sheep in relation to age, sex, nutritional status, management system and flock size was studied at Tangail district, Bangladesh from July to December 2010 by fecal examination. A total of 190 sheep were examined of which 154 (81.1%) were positive for one or more species of helminth parasites. Seven species of helminths were identified, of them three species were trematodes, namely, Fasciola gigantica (8.4%), Paramphistomum spp. (44.2%) and Schistosoma indicum (3.7%); four species were nematodes, namely, Bunostomum sp (19.0%), Trichuris spp. (2.1%), Strongyles (62.6%) and Strongyloides spp. (9.5%). No cestodes were identified. Prevalence of helminths was significantly (p<0.01) higher in young sheep aged >1-2 year (92.7%) than adult aged > 2 years (83.3%) and lamb aged ? 1 year (63.6%). Higher prevalence was recorded in female than in male sheep. In relation to nutritional status and flock size, prevalence of helminths were significantly (p<0.01) higher in poor health and large flock sized animals. It is suggested that helminth infection is widely prevalent in sheep in Tangail district of Bangladesh.DOI: http://dx.doi.org/10.3329/jbau.v10i2.14913 J. Bangladesh Agril. Univ. 10(2): 235-244, 2012

Associação de imunoestimulante com anti-helmíntico no tratamento da verminose em ovinos

Este estudo teve como objetivo verificar a eficiência do uso de imunoestimulante associado a anti-helmíntico no tratamento das helmintoses de ovinos. Os animais do grupo I (n=29) receberam o anti-helmíntico albendazole (11mg kg-1) em administração única e o imunoestimulante composto de Propionibacterium granulosum (16ug kg-1) e lipopolissacarídeo (LPS) de Escherichia coli (1,2ug kg-1) em duas doses com intervalo de 48 horas e os animais do grupo II (n=29) receberam o anti-helmíntico albendazole (11mg kg-1). Amostras foram colhidas semanalmente durante 28 dias para a realização da contagem total e diferencial de leucócitos, hematócrito e contagem de ovos por grama de fezes (OPG). Os animais que receberam imunoestimulante associado a anti-helmíntico apresentaram aumento significativo dos valores de eosinófilos e linfócitos (P<0,05) em relação aos animais que receberam somente anti-helmíntico. Na contagem de ovos por grama de fezes (OPG), não foram observadas diferenças significativas entre os grupos (P>0,05). Com base nesses resultados, pode-se concluir que imunoestimulantes podem ser utilizados associados a anti-helmínticos como alternativa terapêutica no tratamento das helmintíases em ovinos, uma vez que promovem a ativação da resposta imune com participação de células e mediadores importantes para a eliminação de helmintos em ovinos.

Dynamics of infestation of tracers lambs by gastrointestinal helminths under a traditional management system in the North of Tunisia.

The authors present a survey of gastrointestinal helminths of sheep on permanent pastures in the extreme north region of Tunisia (Mediterranean climate). Dynamic infestation of animals has been monitored by using batches of three tracer lambs introduced each two months during 2004 and 2005. These lambs were kept in the pens of veterinary school of Sidi Thabet (Tunisia) during three months and then necropsied. Faecal and blood samples were took from tracer lambs each two months during the whole period, and from animal flock only during 2004. The main helminth genera encountered were Trichostrongylus spp., Teladorsagia spp., Strongyloides papillosus and Anoplocephalidea; occasionaly were found Nematodirus, Oesophagostomum, Chabertia, Cooperia, Trichuris and Paramphistomum. The egg count of the ewes and lambs in the flock showed two peaks. For both ewes and lambs there is a gradual increase from January with a peak in May-June. This first peak is considered to be due to acquisition of infective larvae during the rainy and cold season, as evident from the worm burdens of tracer lambs. The second peak was exclusively observed in ewes during late autumn-early winter (November-December); it has two origins: infestation by third larvae stage and the periparturient rise. The worm burdens of tracer lambs showed that there was a gradual accumulation of nematodes from September- October, reaching a peak in March-April; a very low or naught infection is reported during the dry period (July-August). Infection by Anoplocephalidea was higher during the dry season. This study is primordial for a comprehensive control programme implementation against gastrointestinal helminths.