Nematode parasite infections of domestic pigs in a sub-tropical and high-rainfall area of India

Fourteen hundred and ninety-six domestic pigs, Sus scrofa domestica L., from a sub-tropical and high-rainfall area of India were examined over a period of 18 months to ascertain their nematode parasite spectrum. The eleven species recovered, arranged in descending order of prevalence, are as follows: Ascaris suum, Oesophagostomum dentatum, Bourgelatia diducta, Stephanurus dentatus, Globocephalus connorfilii, Physocephalus sexalutus, Ascarops dentata, A. strongylina, Pseudocruzia orientalis, Setaria bernardi and Gnathostoma hispidum. This is also the first report of the occurrence of Setaria bernardi in pigs in India. A. Suum, the most prevalent species (51.67%) found in the pigs of the region, is presumably of zoonotic importance. Another species of public health significance that was encountered in the survey was Gnathostoma hispidum. The overall infection rate was considerably higher (76.42%) in the low-altitude region than in the high-altitude one (62.50%). The highest level of infection (73.2%) was observed during autumn and the lowest (63.0%) in winter.     

Efficacy of ivermectin against induced gastrointestinal nematode infections in goats

The efficacy of ivermectin (0.08 per cent w/v oral solution) at different dose levels was evaluated against induced infections of adult Haemonchus contortus (21 days old) and Trichostrongylus colubriformis (21 days old) and fourth stage larvae of Oesophagostomum columbianum (17 days old), Ostertagia circumcincta (five days old) and Strongyloides papillosus (five days old). Twenty-five Boergoats (mutton goats) were randomly allocated by bodyweight within each sex to an untreated control group and four ivermectin treatment groups; ivermectin was administered at either 25, 50, 100 or 200 micrograms/kg orally, once. The goats were killed and processed for worm recovery 25 to 27 days after treatment. At 25 micrograms/kg the efficacy of ivermectin varied from 43 per cent for adult T colubriformis to more than 99 per cent for fourth larval stage O columbianum. Ivermectin at 50 micrograms/kg or higher was 99 per cent or more effective against all induced parasite infections with the exception of ivermectin at 50 micrograms/kg against S papillosus (97 per cent). For all parasites there was a statistically significant (P less than 0.05) difference between the control group and the pooled treated groups. No adverse reactions to ivermectin treatment were observed in the goats.     

Investigations on the treatment of cerebrospinal nematode infections in goats

In 17 goats the therapeutical outcome of cerebrospinal nematodiasis, a parasitic infection in the central nervous system with the nematode Elaphostrongylus cervi, is described. The diagnosis was made on the basis of physical findings and cerebrospinal fluid eosinophilia. The therapy was based on the administration of a non-steroidal antiinflammatory drug (flunixin meglumine) and two anthelmintics (fenbendazol, ivermectin) for five days. The response to therapy was documented immediately and 30 days after therapy and by owners report up to 30 months. Eleven goats (64.7%) showed an improvement of the neurological signs directly after therapy. Three had a complete recovery. Signs of a light and middle ataxie were still present in 6 and 2 goats, respectively. Six recumbent goats (35.3%) had to be euthanasied because of a non-therapeutical response. This study has shown a clinical impression of successful use of flunixin meglumine, fenbendazole and ivermectin in goats with light to middle neurological signs. The goats could accommodate the remaining ataxia without showing a reduced production. Goats with high neurological deficits could not be successful treated based on the high degree of the neurological damage.     

国产表阿佛菌素驱除山羊胃肠道线虫的临床试验

对145只自然感染胃肠线虫的山羊进行了国产表阿佛菌素驱除胃肠线虫的临床疗效试验.单次给药治疗21 d后,其0.1、0.2、0.4 mg/kg组的精计驱虫率均为100%,驱净率分别为100%、100%和90%～100%,粗计驱虫率分别为100%、100%和99.4%～100%,均显著优于阳性对照组(0.15%、0和0)和对照药物盐酸左旋咪唑组(38.4%、35%～85%和66.5%～85.9%)(P＜0.05或P＜0.01),表明表阿佛菌素具有明显的驱除胃肠线虫作用,其临床推荐剂量为0.2 mg/kg.     

Gastrointestinal nematode infection does not affect selection of tropical foliage by goats in a cafeteria trial

It is important to determine whether gastrointestinal nematodes (GINs) affect foliage choice of goats leading to confirm the expression of a self-medication behavior. This study investigated the effect of GIN infection on tropical foliage selection by goats. During experimental stage 1 (10 days), goats had a natural mixed GIN infection, and at stage 2 (10 days), goats were treated with effective anthelmintics to maintain them free of GIN infection. During stage 1 the twelve adult goats (32?±?2.3 kg live weight [LW]) were assigned to three groups (n?=?4) according to their initial GIN infection status: HI group, with fecal egg count (FEC) between 1450 and 2150 eggs per g/feces (EPG); MI group, medium FEC (592–1167 EPG); and the NI group, free from GIN infection. Fresh foliage of four tropical plants were offered to goats ad libitum for 1 h daily: Gymnopodium floribundum (high condensed tannin [CT] content, 37–40 %), Mimosa bahamensis (medium CT content, 16–17 %), Leucaena leucocephala (low CT content, 3–5 %), and Viguiera dentata (negligible CT content, 0.6–0.9 %). Jacobs’ selection indexes (JSIs) were estimated for the experimental foliage based on dry matter (DM), CT, or crude protein (CP) intake. During both study stages, individual fecal egg counts were estimated. The JSI patterns of different plant species, based on DM, CT, or CP, were similar irrespective of infection level during stage 1 (HI, MI, and NI) or no GIN infection (stage 2). Thus, irrespective of GIN infection, goats actively selected M. bahamensis (high CT, low CP content) and V. dentata (negligible CT, high CP content) but avoided G. floribundum (high CT, low CP content) and L. leucocephala (medium CT and high CP content). Thus, natural GIN infection did not influence goats’ foliage selection.     

Assessment of genetic variability of resistance to gastrointestinal nematode parasites in Creole goats in the humid tropics

Goat production is widespread in the tropics. Goats are very susceptible to gastrointestinal nematode infection, but there is less evidence of their genetic resistance. Genetic resistance of Creole goats to gastrointestinal nematodes has been studied at Guadeloupe in the French West Indies since 1995. The objective of this research was to investigate genetic variation for resistance to gastrointestinal nematode infection, in order to introduce this trait into breeding schemes. Genetic variability was assessed within a Creole experimental flock. Forty-nine sire groups were characterized at weaning and 55 during fattening after weaning. Kids were naturally infected, mainly by Haemonchus contortus and Trichostrongylus colubriformis. Fecal egg counts were determined once at weaning and every 6 and 7 wk after drenching during fattening. Blood samples were collected every 7 wk during fattening for determination of packed cell volume. Live weights were recorded at weaning and at the beginning and middle of every infection period during fattening. Genetic parameters were estimated using the REML for multivariate animal models. The heritability estimate for transformed fecal egg count was 0.37+/-0.06 at weaning. During fattening, it increased from 0.14+/-0.05 at 4 mo to 0.33+/-0.06 at 10 mo. Heritabilities of packed cell volume ranged from 0.10 to 0.33. At weaning, maternal heritability of fecal egg count reached 0.26 and direct heritability 0.20. After 6 mo of age, maternal effects were found to be unimportant for fecal egg count and packed cell volume. Live weights presented significant genetic variability. Genetic relationships between fecal egg counts and live weight in infected pastures were never significant. Genetic correlations between packed cell volume and live weight decreased from 0.47 to 0.10 from weaning to 10 mo of age. These results demonstrated the feasibility of breeding for improved resistance to nematodes in Creole kids.     

Efficacy of three broad-spectrum anthelmintics against gastrointestinal nematode infections of goats

Groups of 10 goats, harbouring both naturally acquired and experimental infections of gastrointestinal nematodes, were drenched with either levamisole (5 mg kg-1), albendazole (3.8 mg kg-1) or parbendazole (15 mg kg-1), or remained untreated. Haemonchus contortus was the numerically dominant infection, with Strongyloides papillosus, Trichostrongylus colubriformis and Oesophagostomum columbianum also present. At 5-6 days post-treatment, goats were killed and necropsied. Post-mortem worm counts showed that the reduction in mean total worm burdens was 57.4% in levamisole-treated animals, 71.1% in the albendazole group and 85.1% in the parbendazole group. Reductions for H. contortus were 80.2, 87.9 and 83.9% in the levamisole-, albendazole- and parbendazole-treated groups, respectively. These data indicate that the anthelmintics in question are not being applied at an adequate dose rate for goats, and/or resistance to anthelmintics is occurring in the field in Pernambuco State, northeast Brazil.     

Genetic and environmental influences on faecal nematode egg counts of Jamunapari goats in India

The present study was carried out from 1999 to 2003 to determine the genetic and environmental influences of faecal egg count (FEC), an indicator of host resistance, in adult Jamunapari goats with naturally acquired gastrointestinal nematode parasite infections (predominantly Haemonchus contortus). FEC data on 670 records of Jamunapari goats descended from 54 bucks and 208 does were used in this study. Analyses were carried out by restricted maximum likelihood estimation, fitting an animal model. Four different animal models ignoring or including maternal genetic or permanent environmental effects were fitted. Different environmental effects, that is, sampling year, month and the sex of the animals, significantly (P<0.01) influenced FECs in the goats. Direct heritability estimates were inflated substantially for this trait when maternal effects were ignored. The direct heritability estimates for the trait ranged from 0.11 to 0.16 depending on the model used. Low estimates of maternal heritability (m(2)=0.06) and the fraction of variance due to maternal permanent environmental effects (c(2)=0.09) for FECs were observed in the present study. The results suggest that direct and permanent environmental maternal effects were important for this trait; however, maternal additive effects had less impact on this trait. These results also indicate that modest rates of genetic progress appear possible for FECs.     

Comparison of ivermectin and thiabendazole for treatment of naturally occurring nematode infections of goats in Kenya

The anthelmintic activity of thiabendazole (TBZ) at 88 mg kg-1 and ivermectin at 0.2 mg kg-1 was examined in goats with naturally-acquired nematode infections. In one experiment, a herd of 450 does was treated with TBZ or ivermectin at 4-week intervals for 9 months and efficacy was measured by reduction in faecal egg counts after each treatment. In a second experiment, 100 kids were treated with ivermectin and effectiveness measured at 2 and 4 weeks after treatment by comparison of their egg counts with those of nontreated controls. In a third experiment, efficacy of treatment with TBZ and ivermectin was determined by recovery of parasites at necropsy in a controlled test with 15 kids. The results indicated that TBZ generally did not reduce egg counts and only removed 19% of Haemonchus contortus in the controlled test. The efficacy of ivermectin approached 100% for reduction in egg counts and elimination of H. contortus. Species of Ostertagia, Trichostrongylus, Nematodirus and Oesophagostomum also were present in some subjects, but not in sufficient numbers to evaluate effectiveness of treatment.     

Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia

Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.     

Benefit of the control of gastrointestinal nematode infection in goats in the dry zone of Sri Lanka

The benefit of gastrointestinal nematode control in cross-bred goats in the dry area of Sri Lanka was studied throughout 1 year by comparing the performances of three groups: group 1 animals (n = 11) were left untreated against gastrointestinal nematodes; group 2 animals (n = 11) were given monthly anthelmintic treatment. doramectin, at the dose rate of 300 microg/kg bodyweight during the entire study period; group 3 animals (n = 11) were also given monthly doramectin treatment at the dose rate of 300 microg/kg bodyweight but only during the rainy months, October to January and again once in April. All three groups were turned out together on to communal pasture. Tracers were used for the monthly estimation of gastrointestinal nematode burdens. Four untreated animals and a group 3 animal suffered from parasitic gastroenteritis during the study period. When compared with the controls, the treated groups had significantly lower gastrointestinal nematode infection as indicated by faecal egg counts (P<0.01). Faecal egg counts in group 3 were significantly higher than those in group 2 (P < 0.01). When compared with the controls, the treated groups had significantly greater weight gains (P< 0.05). Haemonchus contortus and Trichostrongylus colubriformis were the predominant gastrointestinal nematodes identified from tracers. The worm burden varied according to the rainfall pattern, with very minimal transmission during the dry period which extends from May to August. Under the conditions of this study, the monthly anthelmintic treatments increased weight gains and prevented parasitic gastroenteritis of goats in the dry zone of Sri Lanka.     

Anthelmintic resistance in nematode parasites of goats

Cases of anthelmintic resistance on 3 goat farms in Gippsland were investigated. On the first farm Haemonchus contortus, Trichostrongylus colubriformis and Ostertagia (Teladorsagia) circumcincta were found to be resistant to fenbendazole, but the first 2 species were fully susceptible to levamisole. On the second farm a population of T. colubriformis, resistant to concurrent full doses of levamisole and a benzimidazole, was found to retain this resistance when transferred to sheep. On the third farm, heavy mortality due to Ostertagia and Trichostrongylus spp burdens was arrested only by the use of concurrent full doses of levamisole and oxfendazole; no single anthelmintic was found to be effective. A disturbing rise in the incidence of clinical helminthiosis, often accompanied by anthelmintic resistance, occurred on goat farms in Gippsland early in 1984.     

Gastrointestinal nematode immunization trials in cattle

Three experiments were conducted to immunize calves against Ostertagia ostertagi, Trichostrongylus axei, and T colubriformis. Calves were given intraperitoneal injections with in vitro-grown parasitic larvae of the three species and IV and intraperitoneal injections of exoantigens obtained from culture media used to grow O ostertagi. None of the treatments provided immunity to subsequent oral challenge exposure with normal infective larvae.     

Comparison of nematode infections of the gastrointestinal tract in Angora and dairy goats in a rangeland environment: relations with the feeding behaviour

A study was conducted in order to examine the possible influence of feeding behaviour on differences in the diversity and the intensity of nematode infections of the gastrointestinal tract between two breeds of goats placed in the same rangeland environment. Within the same flock bred on rangeland conditions, 10 Saanen dairy goats and 14 Angora goats were surveyed for 5 months (from May to September) and parasitological and behavioural parameters were measured. The level of nematode infection was estimated by monthly measurements of faecal egg counts whereas the feeding behaviour was assessed every fortnight. During the whole survey, nematode egg excretion was repeatedly higher in the Angora goats compared to the Saanen ones and significant differences were observed in May and September. This difference in egg excretion was related to major difference in feeding behaviour between the two breeds. In contrast with the Saanen does, Angora goats did not show any browsing and resting activities at any date of observation. Hence, Angora goats can be considered mainly as grazers whereas Saanen goats exhibit feeding activities close to browsers. The relative influence of feeding behaviour and host immune response on the susceptibility to gastrointestinal nematode infection in goats is discussed.     

Preliminary comparison of different immune and production components in local and imported Saanen goats reared under a sub-tropical environment

Three objectives were included in this research work. The first objective compared different immune components in healthy mature males, mature females, and female kids of local and imported Saanen goats, reared under a sub-tropical environment. The significantly differing immune components were the blood monocyte percent, blood CD8 count, and the total white blood cell count. The second objective compared the performance of Saanen versus local does. The means of the milk yield and prolificacy of the imported Saanen does were significantly higher than those of the local does (p < 0.05). The third objective compared the immune responses (hemagglutination-HA titers) and complement fixation (CF) titers in mature does of the two breeds to chicken red blood cells (c-RBC). The HA titers showed a significant seroconversion only in imported Saanen (p < 0.05) but not in local does; however, the CF titers increased significantly at 4 weeks following priming with c-RBC in local (p < 0.05) but not in the imported Saanen does. The impact of the differences in blood immune components and responses to antigens in the compared goats on protection potential against prevalent diseases in the sub-tropical zone of the eastern Mediterranean countries is discussed.