Trichostrongylus Axei Research Articles

ABOMASAL PARASITES IN WILD SYMPATRIC CERVIDS, RED DEER, CERVUS ELAPHUS AND FALLOW DEER, DAMA DAMA, FROM THREE LOCALITIES ACROSS CENTRAL AND WESTERN SPAIN: RELATIONSHIP TO HOST DENSITY AND PARK MANAGEMENT

A survey of abomasal parasites in cervids from Central Spain was conducted at 3 sites, Quintos de Mora (Toledo), Maluéñez de Arriba (Cáceres), and La Herguijuela (Cáceres). Commonly occurring helminths belonged to 3 polymorphic species of the Ostertagiinae: Spiculopteragia asymmetricalS. quadrispiculata, Ostertagia leptospicularis/O. kolchida, and O. drozdzi/O. ryjikovi. Trichostrongylus axei was found in very few cases. Ostertagia drozdzi/O. ryjikovi and the minor male morphotype, S. quadrispiculata, are reported for the first time in red deer from Spain. The 3 ostertagiine species are also reported for the first time in fallow deer from Spain. These 3 species of Ostertagiinae are primarily parasites of cervids, and nematode species characteristic of domestic ruminants were not present. Prevalence of infection by gastrointestinal parasites in cervids was high, ranging from 97.5 to 100%, across the 3 areas sampled. Mean intensity of infection and abundance showed a positive relationship to the population density of red deer. Helminth burdens were higher in fallow deer than in the sympatric red deer and may reflect the gregarious social structure and different foraging patterns of fallow deer.

Parasites of domestic and wild animals in South Africa. XLV. Helminths of dairy calves on dry-land Kikuyu grass pastures in the Eastern Cape Province

Successive pairs of approximately 4-month-old Friesland bull calves, raised under worm-free conditions, were exposed to helminth infection for 14 days on dry-land Kikuyu grass pastures at 28-day to monthly intervals, on a coastal farm in a non-seasonal rainfall region of the Eastern Cape Province. With the exception of one pair of calves exposed for 28 days, this procedure was repeated for 28 consecutive months from December 1982 to March 1985. The day after removal from the pastures one calf of each pair was slaughtered and processed for helminth recovery and the other 21 days later. Both members of the last four pairs of calves were killed 21 days after removal from the pastures. Sixteen nematode species were recovered from the calves, and infection with Ostertagia ostertagi was the most intense and prevalent, followed by Cooperia oncophora. The calves acquired the greatest number of nematodes from the pastures from June to October of the first year and from June to August of the second year of the survey. Few worms were recovered from the tracer calves examined from November or December to March or April in each year of the survey. The seasonal patterns of infection with Cooperia spp., Haemonchus placei, Nematodirus helvetianus, Oesophagostomum spp., O. ostertagi and Trichostrongylus axei were all similar and were negatively correlated to atmospheric temperature and evaporation. Slight to moderate arrest in the development of fourth stage larvae occurred from July to September in Cooperia spp., April to July in H. placei, and August to October in O. ostertagi and Trichostrongylus spp. during the first year of the survey. Too few worms were present in the second year to determine a seasonal pattern of arrest. Species survival during the hot and windy summer months appeared to be achieved via a combination of arrested larval development and an ageing residual population of adult worms in the host, and a small extant population of infective larvae on the pastures.

Helminths in a giraffe (<i>Giraffa camelopardalis giraffa<i/>) from a zoo in Spain : research communication

A pregnant female Cape giraffe (Giraffa camelopardalis giraffa) died from an unknown cause in the Aitana Zoo, Alicante, Spain. Neither clinical signs nor macroscopic lesions were observed at necropsy. The alimentary tract was removed and examined for parasites. A total of 2 724 nematodes were found, including Camelostrongylus mentulatus, Trichostrongylus axei, Ostertagia ostertagi, Teladorsagia circumcincta, Teladorsagia trifurcata, Marshallagia marshalli, Trichostrongylus vitrinus, Trichostrongylus colubriformis, Spiculopteragia asymmetrica and Trichuris giraffae. Only T. giraffae and C. mentulatus have been previously reported from giraffes. The other nematodes are common in mouflons, fallow and red deer, which can usually be found in the same paddock as the giraffes in Aitana Zoo. Although its occurrence is unusual in this host, C. mentulatus was the most abundant nematode in our giraffe. This parasite has been related to disease, and even death, in several wild ruminants.

Therapeutic and persistent efficacy of moxidectin 1% nonaqueous injectable formulation against natural and experimentally induced lung and gastrointestinal nematodes in cattle

Four controlled trials were conducted to evaluate the therapeutic and persistent efficacy of a new moxidectin formulation (moxidectin 1% nonaqueous injectable) against nematode parasites in cattle. This injectable moxidectin formulation, given as a single subcutaneous injection at a dose rate of 0.02 ml/kg BW to provide 0.2 mg moxidectin/kg BW, was highly efficacious (>90–100%) against larval and/or adult stages of many species of nematodes in cattle including, Dictyocaulus viviparus, Ostertagia spp., Trichostrongylus axei, Haemonchus placei, Trichostrongylus colubriformis, Cooperia spp., Nematodirus helvetianus, Strongyloides papillosus, Oesophagostomum radiatum and Trichuris spp. This formulation had persistent efficacy of >90% against D. viviparus for at least 6 weeks post-treatment, H. placei and Oe. radiatum for 5 weeks post-treatment, and Ostertagia spp. and T. axei for 2 weeks post-treatment.

Probable multigeneric resistance to macrocyclic lactone anthelmintics in cattle in New Zealand

AIM: To establish the efficacy of topical formulations of eprinomectin and abamectin against naturally acquired abomasal and small intestinal nematode infections in cattle purchased from a North Island bull-beef property. METHODS: A controlled slaughter trial, involving eighteen 6–8-month-old mixed breed calves, was conducted in May 2002. The animals were randomly allocated on the basis of faecal egg count to one of three equal-sized groups (n=6), consisting of an untreated control group and two treatment groups. One of the treatment groups was treated with a topical formulation of eprinomectin, the other with abamectin. Both anthelmintics were administered as a single topical treatment on an individual liveweight basis, at the manufacturer's recommended dose rates of 0.5 mg/kg. All calves were housed in separate groups with no access to pasture throughout the entire trial and were slaughtered 7–10 days after treatment. RESULTS: Both anthelmintic treatments were highly effective (worm count reduction >98%) against Ostertagia ostertagi, Trichostrongylus axei and Cooperia punctata, but were not effective at reducing worm counts significantly of either Cooperia oncophora or Trichostrongylus longispicularis. Against these latter two parasites, worm count reductions of only 72% and 79%, and 81% and 76%, respectively, were recorded following treatment with eprinomectin or abamectin, respectively (all p>0.05). CONCLUSIONS: These results demonstrate evidence of resistance to macrocyclic lactone anthelmintics by C. oncophora and probably T. longispicularis also. CLINICAL RELEVANCE: As well as perhaps providing the first record of resistance to any anthelmintic by T. longispicularis, the present findings may also represent the first case of resistance to macrocyclic lactone anthelmintics exhibited by more than one parasite species at a time in cattle in New Zealand.

91. The safety of bovine gelatin with regard to the bovine spongiform encephalopathy agent

Fifteen roe deer were examined at necropsy from Northern Turkey in the period 2006–2010 for the helminth infections. Totally 6470 helminth specimens were collected and identified by morphological criteria. Twenty-five helminth species were identified (1 of the Class Trematoda, 1 of Cestoda and 23 of Nematoda). Dicrocoelium dendriticum (Prevalence 20%) was found in liver. Cysticercus tenuicollis (6.6%) was found in mesentery. Haemonchus contortus (53.3%), Ostertagia leptospicularis (73.3%), O. leptospicularis (minor morph: kolchida) (53.3%), Ostertagia ostertagi (26.6%), Spiculopteragia spiculoptera (66.6%), S. spiculoptera (minor morph: mathevossiani) (6.6%), Teladorsagia circumcincta (40.0%), T. circumcincta (minor morph: davtiani) (6.6%), T. circumcincta (minor morph: trifurcata) (6.6%), Trichostrongylus axei (66.6%) were found in abomasum. Trichostrongylus andreevi (6.6%), T. colubriformis (6.6%), T. longispicularis (26.6%), T. vitrinus (40.0%), T. capricola (6.6%), Cooperia oncophora (26.6%), C. punctata (6.6%), Nematodirus filicollis (66.6%), and Capillaria bovis (26.6%) were found in small intestine. Oesophagostomum venulosum (46.6%), Chabertia ovina (26.6%), and Trichuris ovis (13.3%) were found in large intestine. Dictyocaulus capreolus (6.6%) was found in lungs.

Relação entre desempenho e infecções por nematódeos gastrintestinais em bovinos Nelore em crescimento

Este estudo teve por objetivo verificar a associação entre o desempenho e a carga parasitária de 28 machos inteiros da raça Nelore (a partir de um ano de idade), naturalmente infectados por nematódeos gastrintestinais. De novembro de 1999 a junho de 2000, os animais foram pesados quinzenalmente, período no qual foram colhidas amostras de fezes e de sangue para a realização, respectivamente, de exames coprológicos e sangüíneos. Os dados da contagem de ovos por grama de fezes (OPG) ajustaram-se ao modelo de distribuição binomial negativa, indicando que a distribuição de nematódeos no rebanho é agregada. Não ficou evidenciada associação entre ganho de peso e contagem de OPG, e entre contagem de OPG e volume globular (VG). De 10 coeficientes de correlação entre ganho de peso e VG, oito foram negativos, mas apenas dois significativos (P<0,05). As estimativas de repetibilidade da contagem de OPG, LOG (OPG+1) e VG foram de 0,26, 0,25 e 0,33, respectivamente. Cooperia punctata foi a espécie mais freqüentemente encontrada parasitando os animais. Além dessa espécie, foram detectados os seguintes nematódeos: Haemonchus placei, Haemonchus similis, Trichostrongylus axei, Bunostomum phlebotomum e Oesophagostomum radiatum. O parasitismo por nematódeos gastrintestinais aparentemente não prejudicou o desenvolvimento dos animais estudados.

Etude épidémiologique des helminthes gastro-intestinaux des caprins en Moyenne Guinée

Une étude épidémiologique du parasitisme a été menée en Moyenne Guinée sur 102 caprins de race Djallonké. Six à neuf chèvres ont été autopsiées tous les mois pendant une année. Les résultats obtenus ont révélé la présence des 11 espèces d’helminthes suivantes par ordre de prévalence : Haemonchus contortus (94 p. 100), Trichostrongylus colubriformis (84 p. 100), Oesophagostomum columbianum (75 p. 100), Cysticercus tenuicollis (71 p. 100), Trichostrongylus axei (70 p. 100), Cooperia sp. (55 p. 100), Trichuris ovis (55 p. 100), Moniezia sp. (39 p. 100), Gaigeria pachyscelis (39 p. 100), Strongyloides papillosus (25 p. 100) et Paramphistomum sp. (12 p. 100). Une infestation modérée avec des variations saisonnières des parasites a été observée. Aucune hypobiose n’a été constatée. Les excrétions d’oeufs et les intensités parasitaires des nématodes gastro-intestinaux ont montré des fluctuations avec un pic entre juillet et octobre durant la saison des pluies. Les animaux âgés de plus de 30 mois et les femelles en lactation avaient des charges parasitaires plus élevées. Un schéma de traitement sélectif des animaux infestés a été envisagé.

Titration of subcutaneously administered eprinomectin against mature and immature nematodes in cattle.

Eprinomectin has been approved for use as a topically applied endectocide for beef and dairy cattle. To determine if eprinomectin has utility as an injectable anthelmintic, it was titrated at 0.05, 0.1, and 0.2 mg/kg s.c. against adult (Trial 1) and at 0.05, 0.1, 0.14, and 0.2 mg/kg s.c. against immature (Trial 2) stages of lung and gastrointestinal nematodes in cattle. In Trial 1, every dose of subcutaneously delivered eprinomectin showed maximal or near-maximal (> or = 99%) efficacy against Haemonchus placei, Ostertagia ostertagi, Trichostrongylus axei, T colubriformis, Cooperia punctata, Nematodirus helvetianus, Oesophagostomum radiatum, and Dictyocaulus viviparus. Adult C. oncophora was the only exception. However, even against this species, the lowest dose of 0.05 mg/kg showed 93% efficacy, and the efficacious dose necessary to kill 95% (ED95) of adults was 0.056 mg/kg. In Trial 2, every dose of subcutaneously delivered eprinomectin showed maximal or near-maximal (> or = 99%) efficacy against the immature stages of all of the above species of endoparasites. As a result, ED95 values could not be calculated. Consequently, the exquisite potency against endoparasites through parenteral administration suggests that eprinomectin may also have potential utility as an injectable product for cattle.

Resistance to macrocyclic lactone anthelmintics by Haemonchus contortus and Ostertagia circumcincta in sheep in New Zealand

AIM: To establish the efficacy of oral formulations of ivermectin and moxidectin against naturally acquired abomasal nematode infections on a North Island sheep farm. METHODS: Two controlled slaughter trials were undertaken. In the first, 30 sheep on pasture were randomly allocated on the basis of faecal egg count to 1 of 3 groups, comprising an untreated control group and 2 treatment groups. One treatment group was given a single oral dose of ivermectin and the other a single oral dose of moxidectin, both at the manufacturer's recommended dose rates of 0.2 mg/kg liveweight. Six days after treatment, all animals were slaughtered and their abomasa recovered for worm counting. The second trial, which involved 47 animals, was essentially the same as the first except that, as well as involving the slaughter of 30 sheep from all 3 groups, 6 days after treatment, it also included a further 8 untreated control animals and 9 moxidectin treated animals which were slaughtered 27 days after treatment. RESULTS: At 6 days after treatment, moxidectin was highly effective against all 3 of the abomasal nematodes present. While ivermectin was similarly effective against Trichostrongylus axei 6 days after treatment, it was not effective against either Ostertagia circumcinta or Haemonchus contortus, against which average efficacies of only 63.6% and 61.6%, respectively, were recorded. At 27 days after treatment, moxidectin, was also highly effective against T. axei (97.3% reduction) but not against either H. contortus (71.4% reduction) or O. circumcinta (61.0% reduction). CONCLUSIONS: These results provide the first record of macrocyclic lactone resistance in H. contortus in sheep or in any other host in New Zealand, and the first case where such resistance has been exhibited in more than one parasite species at a time. Although the therapeutic efficacy of moxidectin was high against these resistant H. contortus and O. circumcincta strains, resistance to moxidectin was indicated by its diminished prophylactic activity against them. It is suggested that this reduction in the prophylactic activity of moxidectin is also likely to reduce its apparent current high therapeutic efficacy. CLINICAL RELEVANCE: As well as providing further evidence that it can no longer be automatically assumed that macrocylic lactone anthelmintics will be effective on sheep farms in this country, these findings also present a warning that increasingly complex parasite control options may have to be faced in the future.

A multiplex PCR assay for differentiating economically important gastrointestinal nematodes of cattle

A multiplex polymerase chain reaction (PCR) test was developed for identifying gastrointestinal (GI) nematodes that commonly infect cattle. This assay was developed using adult-derived genomic DNA and shown capable of discriminating parasite eggs from the feces of experimentally-infected animals at both the species and genus levels. Sequence data from internal (ITS) and external (ETS) transcribed spacers of the ribosomal DNA (rDNA) repeats as well as the 3′-end of the small subunit rDNA and 5′-end of the large subunit rDNA were used to generate five primer sets which, when used simultaneously in a multiplex PCR, produce a unique electrophoretic DNA banding pattern characterized by a single DNA fragment for Ostertagia ostertagi (257 bp), Haemonchus placei (176 bp), Oesophagostomum radiatum (329 bp), Trichostrongylus colubriformis (243 bp) and Cooperia oncophora (151 bp). In a similar manner, the constructed primer sets amplified DNA from Ostertagia lyrata, Haemonchus contortus, Trichostrongylus axei, Cooperia surnabada and Cooperia punctata. With respect to H. contortus, a closely migrating doublet was generated suggesting size heterogeneity in the ETS which is consistent with multiple rDNA repeat units within this species. PCR analyses using mixtures of monospecifically-purified nematode eggs indicated a sensitivity of less than 0.5 egg-DNA equivalent per species. Although, not designed as a quantitative technique, relative PCR signal intensities corresponded to relative egg burdens within the DNA samples from mixed species of eggs.

The epidemiology of gastrointestinal nematodes of dairy cattle in central Kenya.

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bimonthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March-June and October-December) and lowest during the dry seasons (July-September and January-February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.

The Dynamics, Prevalence and Impact of Nematode Infections in Organically Raised Sheep in Sweden

A three-year survey (1997–99) was carried out on organically reared sheep flocks throughout Sweden. The aim was to determine the prevalence and intensity of nematode infections and to establish relationships between sheep management practices and parasite infections. Faecal samples from ewes and lambs were collected from 152 organic flocks around lambing-time and during the grazing-period for analysis. Results were compared with the different management practices that farmers use to prevent parasitism in their flocks. A high proportion of the flocks was infected with nematodes. The most prevalent species were Haemonchus contortus, Teladorsagia circumeincta, Trichostrongylus axei, T. colubriformis and Chabertia ovina and infections progressively increased during summer in lambs grazing on permanent pastures. Severity of parasitic infection in lambs was highly dependent on egg output from the ewes. H. contortus was found in 37% of the flocks, even at latitudes approximating the Polar Circle. Nematodirus battus was recorded for the first time in Sweden during the course of this study. Lambs turned out onto permanent pasture showed higher nematode faecal egg counts (epg) than lambs that had grazed on pastures, which had not carried sheep the previous year. This beneficial effect of lambs grazing non-infected pastures persisted if the ewes were treated with an anthelmintic before turn-out and if the lambs were kept on pastures of low infectivity after weaning. In lambs, the prevalence and the magnitude of their egg counts were higher during autumn in flocks where lambs were slaughtered after 8 months of age, compared with flocks where all lambs were slaughtered before this age. These results will be used in providing advice to farmers of ways to modify their flock management in order to minimise the use of anthelmintics, but at the same time efficiently produce prime lambs.

Persistent efficacy of topical eprinomectin against nematode parasites in cattle.

Six studies were conducted to evaluate the persistent efficacy of eprinomectin pour-on against experimental challenges with infective nematode larvae in calves. In each study, calves were randomly assigned to one untreated group and up to four test groups, which were treated with eprinomectin at 500 microg/kg body weight at weekly intervals before single bolus challenge. The calves were necropsied approximately 4 weeks after challenge infection for nematode recovery. Eprinomectin pour-on provided > or =90% efficacy against challenge with Haemonchus placei, Trichostrongylus axei and T. colubriformis at 21 days after treatment and against Cooperia oncophora, C. punctata, C. surnabada, Dictyocaulus viviparus, Nematodirus helvetianus, Oesophagostomum radiatum and Ostertagia ostertagi at 28 days after treatment.

The epidemiology of nematode and fluke infections in cattle in the Red River Delta in Vietnam

Over a period of 13 months, faecal samples were collected monthly from approximately 45 cattle over 3 months of age. Additionally, 74 calves of 1–2 months were sampled to determine the presence of Toxocara vitulorum eggs. Individual egg counts and infective strongyle larvae from pooled faecal samples were examined. Post-mortem worm counts were carried out on six groups of tracer calves ( n=12) that had been kept for 4 weeks on pasture in and around the village studied. The following helminths were identified: T. vitulorum, Cooperia punctata, C. pectinata, C. oncophora, Oesophagostomum radiatum, Trichostrongylus axei, T. colubriformis, Haemonchus spp., Fasciola spp. and Paramphistomum spp. In 8% of the samples collected from young calves, individual egg counts for T. vitulorum were found indicative for pathogenic worm burdens. Strongyle egg counts and worm counts indicated that transmission is low without a distinct seasonality. In animals of 3–9 months old, a strongyle egg count peak can be demonstrated which at a higher age steadily and significantly decreased. In faecal cultures Cooperia spp. were most prominent in all age groups throughout the year with the exception of the period September–November when Haemonchus spp. and Oesophagostomum spp. were most prevalent. Fasciola spp. eggs were found in 22% of the collected faecal samples and the egg counts were low indicating that the intensity of Fasciola spp. infection is mild. Based on the present data, regular anthelmintic treatments seem not to be justified, except for a single treatment at the age of 2 weeks against toxocariosis.

A study to evaluate the field efficacy of ivermectin, fenbendazole and pyrantel pamoate, with preliminary observations on the efficacy of doramectin, as anthelmintics in horses.

The efficacy of ivermectin, fenbendazole, pyrantel pamoate and doramectin was evaluated under field conditions at 2 sites in the Free State Province of South Africa. The study involved 25 horses at each site, divided into 5 groups of equal size. Ivermectin, fenbendazole and pyrantel pamoate were administered orally at doses of 0.2, 10 and 19 mg/kg respectively. Doramectin was administered by intramuscular injection at a dose of 0.2 mg/kg. Treatment efficacy was based on the mean faecal egg count reduction 14 days post treatment. At site A a faecal egg count reduction of 100% was found after treatment with ivermectin, fenbendazole and doramectin. A 96.1% reduction was found after treatment with pyrantel pamoate. At site B ivermectin and doramectin produced a 100% reduction in faecal egg counts, fenbendazole produced an 80.8% reduction and pyrantel pamoate a 94.1% reduction. Doramectin produced a 100% reduction in faecal egg counts at both sites, despite not being registered for use in horses. In addition, the results indicated reduced efficacy of fenbendazole at site B, which suggested benzimidazole resistance. Larval cultures showed that cyathostomes accounted for between 86 and 96% of pre-treatment parasite burdens at both sites. Other helminths identified in the faecal samples were Strongylus spp. and Trichostrongylus axei.

Host specificity of abomasal nematodes in free ranging alpine ruminants

Abomasums from 641 alpine wild ruminants representing five different species ( Cervus elaphus, Capreolus capreolus, Rupicapra rupicapra, Capra ibex, Ovis musimon) and from 19 domestic sheep ( Ovis aries) from alpine areas were examined in order to investigate the host-specificity of abomasal helminths. Nine out of 20 helminth species were found in at least five different host species. A discriminant analysis was able to significantly discriminate the hosts on the basis of their helminth community composition with the exception of O. musimon and O. aries. Based on the correlation between each variable represented by helminth species with the most explanatory discriminant axis, it was possible to classify helminths into specialists and generalists. Specialists are represented by the dominant species in a community of an host species or family while generalists appear in the communities of many different hosts as intermediate species. Due to the pathogenic potential of some of these generalist species (i.e. Haemonchus contortus, Trichostrongylus axei) and their ability to adapt easily to the conditions found in several different hosts, they appear to be the most important from a sanitary point of view.

Nematode parasites of adult dairy cattle in the Netherlands

Abomasa, blood samples and faecal samples for examination of nematode infections were collected from 125 dairy cows during the period November 1997–October 1998. Of these, 12 had no grazing history and were, therefore, excluded from this study. From the remaining 113, 88.5% had nematode eggs in the faeces. Larval identification of the positive cultures showed that Ostertagia spp. larvae were most frequent (97%), followed by Trichostrongylus spp. (29%), Oesophagostomum spp. (23%), Cooperia punctata (20%), Cooperia oncophora (4%), Haemonchus contortus (2%) and Bunostomum phlebotomum (1%). The geometric mean EPG was 2.4. Two cows excreted larvae of Dictyocaulus viviparus (0.1 and 0.6 LPG resp.). Worms were found in the abomasa of 108 cows (96%). In all these abomasa Ostertagia spp. was present (100%). Trichostrongylus axei was found in 47 abomasa (43.5%) and two cows (2%) were infected with Capillaria bovis. The geometric mean of the total abomasal worm counts was 1743 and of Ostertagia spp. alone 1615. Almost all male worms were Ostertagia ostertagi, only occasionally Skrjabinagia lyrata was found. Early fourth larval stages (EL-4) were particularly present during the winter months: maximum in December (91.7%) and lowest in October (3.3%). Worm burdens were highest in young cows (<3 years) and older cows (>10 years). The highest individual abomasal worm count was 99,800 with 86% EL-4. Eighty-six cows (76%) had a low to moderate (100–10,000) and 22 cows (20%) a high (>10,000) total worm burden. Ostertagia specific antibodies were highest in late summer and autumn and lowest in spring and early summer. The same pattern, although not so pronounced, was observed for the serum pepsinogen values. No clear seasonal pattern was found for the Cooperia specific antibodies. Antibodies against D. viviparus were detected in seven cows (6%).

Epidémiologie des nématodes gastro-intestinaux des bovins dans la région centre de la Côte d'Ivoire

De février à décembre 1997, six bovins de race N'Dama, provenant de la zone centre de savane humide de la Côte d'Ivoire, ont été autopsiés chaque mois. Quatorze espèces ou genres de parasites ont été mis en évidence: 8 nématodes, 2 trématodes, 1 cestode et 3 protozoaires. Tous les animaux étaient infestés par au moins l'une des espèces suivantes de nématodes gastrointestinaux: Haemonchus sp. (95 p. 100), Cooperia punctata (50 p. 100), Oesophagostornum radiatum (35,5 p. 100), Trichostrongylus axei (30 p. 100), Cooperia pectinata (8,1 p. 100) et Trichuris sp. (1 6 p. 100). Setaria labiatopapillosa a été rencontrée chez 30,6 p. 100 des animaux, des microfilaires chez 24,1 p. 100, des paramphistomes chez 80,6 p. 100, et Moniezia sp. chez 15 p. 100. Des trypanosomes et Babesia spp. ont été trouvés chez respectivement 11,2 et 3,6 p. 100 des animaux. Les excrétions d'oeufs et les intensités parasitaires des nématodes gastro-intestinaux ont montré des fluctuations avec des pics en mai et en septembre-octobre, périodes correspondant aux saisons des pluies. Les animaux âgés de 1-3 ans avaient des intensités parasitaires plus élevées que ceux âgés de plus de 3 ans (P &lt; 0,05). Aucune hypobiose larvaire n'a été détectée. En dépit de conditions climatiques humides favorables, les intensités parasitaires de ces bovins de race N'Dama, provenant de systèmes d'élevage de type extensif, étaient relativement faibles. Des traitements anthelminthiques ne seraient alors justifiés que chez les jeunes animaux.

Examination of gastrointestinal helminth in livestock grazing in grassland of Bangladesh.

To determine association of grassland with parasitic diseases of livestock in Bangladesh, the 'Tracer' animals (two cow calves and two goats) were released for a month in a grassland used for communal grazing of livestock near school premise in Kanthal, Trishal, Mymensingh, Bangladesh. After slaughtering of the tracer animals, their gastrointestinal tract examination revealed six species of nematode and one cestode. The nematode species were Haemonchus contortus, Trichostrongylus axei, Mecistocirrus digitatus, Oesophagostomum spp., Trichuris spp. and Bunostomum sp. The cestode was one of the genus Moniezia. With this preliminary study, grasslands are thought to be one of the main sources of gastrointestinal parasitic diseases of livestock in Bangladesh.