Prevalence and seasonal incidence of larval and adult cestode infections of sheep and goats in eastern Ethiopia

A study on the prevalence and seasonal incidence of cestode parasite infections of sheep and goats was carried out in eastern Ethiopia for 2 years (May 2003-April 2005). During this period, viscera including liver, lungs, heart, kidneys and the gastro-intestinal tract were collected from 655 sheep and 632 goats slaughtered at four abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga. At the abattoirs the abdominal, thoracic and pelvic cavities as well as the muscle surfaces of all animals were visually examined for the presence of larval (cystic) stages of cestode parasites. The viscera were transported within 24 h to the parasitology laboratory of Haramaya University and were examined for larval and adult cestodes following standard procedures. The most prevalent metacestodes (larval cestodes) were Cysticercus ovis (Taenia ovis), Cysticercus tenuicollis (T. hydatigena) and hydatid cysts (Echinococcus granulosus). In sheep, the overall prevalence was 26% for C. ovis, 79% for C. tenuicollis, and 68% for hydatid cysts. Similarly, for goats, the corresponding prevalence was 22%, 53% and 65%, respectively. The difference between sheep and goats in prevalence of C. tenuicollis was significant. The high prevalence of hydatid cysts in both sheep and goats indicates that cystic echinococcosis/hydatidosis is a public health problem in these regions which requires implementation of control measures, including public health education, strict meat inspection and control of stray dogs. The results of the survey also implies that infections of small ruminants with these metacestodes are responsible for condemnation of substantial quantities of affected organs and muscles and therefore of direct economic importance. Intestinal infections with adult tapeworms of Moniezia expansa, Avitellina centripunctata and Stilesia globipunctata, and bile duct infections with Stilesia hepatica were also common in both sheep and goats. In sheep, the overall prevalence of these tapeworms were 61%, 20%, 24% and 39%, respectively. Similarly, the overall prevalence of these parasites in goats was 53%, 21%, 27% and 36%, respectively.     

Assessment of anthelmintic resistance in nematode parasites of sheep and goats owned by smallholder farmers in eastern Ethiopia

The anthelmintic resistance status was investigated of nematode parasites of sheep and goats owned by smallholder farmers in communities that received breeding stock from a source where a high level of anthelmintic resistance has been reported. The investigation used the faecal egg count reduction technique, whereby suitable animals within each of eight separate communities were pooled to achieve the numbers required to conduct separate tests for both sheep and goats. Anthelmintics tested were albendazole (ABZ), tetramisole (TET), a combination (ABZ $+$ TET) and ivermectin (IVM), at the manufacturers' recommended dose rates. Results showed that there was no evidence of anthelmintic resistance in nematode parasites of either sheep an goats in any community. This indicates that dilution of resistant parasites imported with introduced breeding stock, and the low selection pressure imposed by the smallholder farmers themselves, has prevented anthelmintic resistance from emerging in nematode parasites of small ruminants in these communities.     

Climate and the epidemiology of gastrointestinal nematode infections of sheep in Europe

The free-living stages of gastrointestinal nematode parasites of sheep are strongly affected by climate. Thus, extreme heat and cold are detrimental to development and survival, while, within tolerable limits, increasing temperatures generally accelerate development but increase mortality. Moisture is needed for development and translation of larvae from faeces to pasture, and so rainfall is a limiting factor for transmission. Together, these factors underpin seasonal patterns of infection in sheep, as well as geographic variation in the epidemiology and relative importance of different species within Europe. Local knowledge and experience enable treatment to be targeted appropriately to prevent dangerous levels of infection. This traditional know-how can be supplemented by predictive epidemiological models, built on thorough understanding of the influence of climate on larval availability. However, management also has a dominant role in determining patterns of infection, and is itself influenced by climate. Current geographic variation in nematode epidemiology across Europe, and knowledge of systems from outside Europe, can provide only limited perspectives on the likely effects of climate change on disease in future. This is because disease arises from complex interaction between host and parasite factors, and the implementation of optimal control strategies to meet new challenges will be slowed by the inertia of current systems. Approaches to nematode control must therefore take account not only of parasite biology, but also the forces that shape sheep farming systems and management decisions.     

Prevalence of gastrointestinal helminths,lungworms and liver fluke in sheep and goats in Norway

The present study describes the occurrence of various gastrointestinal helminths, lungworms and liver flukes in Norwegian sheep and goats as assessed from faecal samples and post mortem examinations performed between 2007 and 2010. Faecal samples for gastrointestinal nematode egg counts were collected from 77 sheep flocks and 30 dairy goat flocks from three geographical regions in Norway. Additionally, thirty-two lambs and 16 adult goats were euthanized for necropsy examination and for identification of adult gastrointestinal nematodes and tapeworms, lungworms and liver flukes. The survey showed that there was a higher mean excretion of trichostrongyle eggs in sheep than in goats at the individual level (392 EPG vs. 154 EPG, p < 0.001). For both host species, the mean prevalence and intensity of excreted trichostrongyle eggs were significantly higher in the southern coastal region compared with the inland and northern regions (p < 0.001). Third stage larvae of Trichostrongylus/Teladorsagia, Haemonchus and Nematodirus type were the most prevalent ones in the coprocultures from sheep, whereas larvae of Trichostrongylus/Teladorsagia and Nematodirus type dominated in goats. The most prevalent gastrointestinal nematode species found at necropsy was Teladorsagia circumcincta (75.0 and 81.2% respectively in sheep and goats), while the largest mean worm burdens were recorded for Haemonchus contortus in sheep (724 ± 623) and T. circumcincta in goats (377 ± 529). Other gastrointestinal nematode species were present at low prevalence or in low numbers.     

Resistance of Santa Ines and crossbred ewes to naturally acquired gastrointestinal nematode infections

This trial was carried out in Piracicaba, São Paulo State, Brazil, to comparatively evaluate the degree of resistance to naturally acquired gastrointestinal nematode infections in sheep of the following genetic groups: purebred Santa Ines (SI), SI crossbred with Dorper (DO × SI), Ile de France (IF × SI), Suffolk (SU × SI), and Texel (TE × SI). Fifteen ewes from each group were raised indoors until 12 months of age. At this age, they were moved to pasture that was naturally contaminated by nematode infective larvae and were evaluated from December to May, 2007. Rainfall ranged from 267 mm in January to 37 mm in April. Maximum and minimum mean temperatures ranged from 32.5 °C to 19.0 °C in March and from 25.9 °C to 12.8 °C in May. There was an increase in the mean number of eggs per gram of feces (EPG) after animals were placed on pasture with significant difference between the SI (80 EPG) and IF × SI (347 EPG) groups in January; and the DO × SI (386 EPG) and TE × SI (258 EPG) groups in May. The highest mean fecal egg count (FEC), 2073 EPG, was recorded for the TE × SI group in February. All groups showed a progressive reduction in body weight throughout the experiment of 12.0% (TE × SI) to 15.9% (SU × SI). In general, the animals with the highest FEC presented the lowest packed cell volumes (PCV); the highest correlation coefficient between FEC × PCV occurred in the SU × SI sheep in January (r = −0.70; P < 0.01). Similarly, there was an inverse relationship between FEC and blood eosinophil values, with the highest correlation coefficient in the TE × SI sheep in February (r = −0.64; P < 0.05). Immunoglobulin G (IgG) levels against Haemonchus contortus antigens increased in all groups as a result of the exposure to parasites and remained relatively constant until the end of the study, with the exceptions of SU × SI and TE × SI, which showed a rise in IgG levels during the last sampling that coincided with a reduction in mean FEC. In conclusion, crossbreeding Santa Ines sheep with any of the breeds evaluated can result in a production increase and the maintenance of a satisfactory degree of infection resistance, especially against H. contortus and Trichostrongylus colubriformis, the major nematodes detected in this flock.     

The effect of long-term feeding of fresh and ensiled cassava (Manihot esculenta) foliage on gastrointestinal nematode infections in goats

The benefit of long-term feeding of fresh or ensiled cassava foliage on gastrointestinal parasite in goats was evaluated. Eighteen male goats (15.15 ± 2.83kg and between 4–6months) were randomly allocated into three treatments supplemented with 200g of wheat bran head⁻¹ day⁻¹. All groups were fed ad-libitum on either grass (CO), fresh cassava (CaF) or ensiled cassava foliage (CaS). At the beginning of the trial, each goat was inoculated with 3000 L3 containing ≈50% Haemonchus contortus. Individual LWt, FEC and PCV were measured at weekly intervals for 10weeks. At the termination of the experiment all goats were slaughtered for worm recovery and enumeration. The goats in CaF and CaS had similar weight gains while those in CO lost weight (p < 0.05) through the trial. FEC in CaF and CaS were lower (p < 0.05) than CO during the patency of parasite infections, but there was no difference between CaF and CaS goats. PCV of all groups decreased from above 30% to around 25% at the end of the trial. The compositions of established worm burdens were mainly H. contortus (19–40%) and Trichostrongylus colubriformis (55–76%). TWB did not differ among the groups, however, CaS significantly reduced H. contortus burdens, as compared to CaF and CO (p ≤ 0.005). Thus, ensiled cassava foliage reduced the H. contortus population while the fresh foliage only reduced worm fecundity.     

Toxoplasmosis in sheep,goats and cattle in central Ethiopia

In a seroepidemiological survey using an indirect haemagglutination assay, the prevalence rate of toxoplasmosis in central Ethiopia was 22.9% of 899 sheep, 11.6% of 753 goats and 6.6% of 785 cattle. There were high titres of 1:256 or more which suggest current infections. These results indicate that toxoplasmosis may be an important cause of reproductive wastage in small ruminants. The public health significance of this disease is discussed. Improved hygiene and management could reduce the prevalence of the disease.     

Development and survival of free-living stages of gastrointestinal nematodes of sheep and goats on pasture in the Nigerian derived savanna

Four grass plots were sequentially contaminated with goat faeces containing known numbers of unembryonated eggs of predominantly Haemonchus contortus and Trichostrongylus spp. between October 1982 and April 1983. Four other plots were similarly contaminated with sheep faeces between February and May 1987. An additional plot was repeatedly contaminated with sheep faeces from February to April 1987. Populations of free-living stages in faeces and of infective larvae (L₃) in the herbage were subsequently monitored until the end of April and June of 1983 and 1987 respectively. During February and May 1987 two control cultures of sheep faeces were incubated in the laboratory at 25°C–30°C and at a constant temperature of 50°C and the free-living development was also monitored. L₃ developed very readily in the faeces cultured at 25°C–30°C and in those spread on a grass plot in October, at the end of the wet season, but developed less on the plot contaminated in May at the start of the wet season. Worm eggs in faeces deposited on plots during the hot dry season (December to April) or incubated at 50°C died and disintegrated after 24–48 h exposure to the high environmental temperatures. The results indicate that it is unlikely that gastrointestinal nematodes of sheep and goats can develop or survive on open pasture during the dry season in the Nigerian derived savanna zone.     

Occurrence and antimicrobial resistance of Salmonella serovars in apparently healthy slaughtered sheep and goats of central Ethiopia

The present study was undertaken to determine the occurrence, distribution and antimicrobial resistance pattern of Salmonella serovars in apparently healthy slaughtered sheep and goats in central Ethiopia. A total 1224 samples consisting of faeces, mesenteric lymph nodes, liver, spleen, and abdominal and diaphragmatic muscle samples were collected from 104 sheep and 100 goats. Salmonella was isolated from 12 of 104 (11.5%) sheep and 3 of 100 (3%) goats. Of the total 624 and 600 samples examined from sheep and goats, 18 (2.9%) and 4 (0.7%), respectively, were Salmonella positive. The 22 Salmonella isolates belonged to 9 different serovars. The common serovars isolated were S. typhimurium, followed by S. heidelberg, S. reading, S. give, and S. poona. Seven of the 22 isolates (31.8%) were multidrug-resistant to various antimicrobials.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

Trematode infections in pregnant ewes can predispose to mastitis during the subsequent lactation period

Objective was to investigate if trematode infections predispose ewes to mastitis and/or metritis. We used 80 trematode-infected ewes: primigravidae in group P-A and multigravidae in M-A remained untreated, primigravidae in P-B and multigravidae in M-B were drenched with netobimin and multigravidae in M-C were given rafoxanide. We collected faecal samples for parasitological examination, blood samples for β-hydroxybutyrate concentration measurement and uterine content, teat duct material and milk samples for bacteriological examination. We found significant differences in blood β-hydroxybutyrate concentrations between M-A, M-B and M-C during pregnancy (P ? 0.002). We did not observe significant differences between groups regarding development of metritis (P > 0.83). We found that for M-A, M-B and M-C ewes, respectively, median time to first case of mastitis was 5.75, 21 and 6.75 days after lambing (P = 0.003) and incidence risk of mastitis was 0.308, 0.069 and 0.222 (P = 0.047). We postulate that trematode infections predispose ewes to mastitis; perhaps, increased β-hydroxybutyrate blood concentrations adversely affect mammary cellular defences. This is the first report associating parasitic infections with mastitis in sheep.     

Epidemiology and seasonal dynamics of gastrointestinal nematode infections of sheep in a semi-arid region of eastern Ethiopia

A study on the epidemiology and seasonal dynamics of gastrointestinal nematode infections of sheep was carried out in a semi-arid region of eastern Ethiopia for 2.5 years (May 2003 to September 2005). The experimental flock comprised a total of 60 Black Head Ogaden sheep, consisting of four equal groups of young male and female and old male and female sheep. These grazed on communal pastures together with a larger university flock, as well as with animals owned by neighbouring small-holder farmers. A new experimental flock was established each year of the study. Parasitological data (EPG, faecal culture L3, PCV and FAMACHA estimates) and animal performance (weight change) were recorded each month on all experimental animals. In addition, four tracer lambs were assigned each month to the flock to determine the seasonal patterns of infective larvae acquired from pasture. Results showed distinct seasonal patterns associated with the bi-modal annual rainfall. High levels of infection occurred during the short and long rain seasons with peaks occurring in May and September of each year. Haemonchus contortus was the most prevalent parasite, followed by Trichostrongylus spp., with a number of other nematode species being occasionally recorded. H. contortus showed and increased propensity to undergo arrested development during the dry seasons. Correlations between EPG and PCV, EPG and FAMACHA eye scores, and PCV and FAMACHA eye scores were all highly significant (P<0.001). However, there was no significant association between the EPG and LW of the study animals during each study year. This information will provide a basis for developing epidemiologically based control strategies for gastrointestinal nematode parasites that are appropriate for flocks owned by small-holder farmers of semi-arid areas of eastern Ethiopia.     

The in vitro effect of six antimicrobials against Mycoplasma putrefaciens, Mycoplasma mycoides subsp. mycoides LC and Mycoplasma capricolum subsp. capricolum isolated from sheep and goats in jordan

Respiratory disease in sheep and goats is a major problem in Jordan and is often associated with Mycoplasma species. Without effective vaccines, control is mainly by chemotherapy, but the uncontrolled use of antimicrobials has led to concerns about the potential development of antimicrobial resistance. The in vitro effect of chloramphenicol, florfenicol, enrofloxacin, tylosin, erythromycin and oxytetracycline was determined against 32 isolates of Mycoplasma species-M. mycoides subsp. mycoides LC (6), M. capricolum subsp. capricolum (8) and M. putrefaciens (18), all isolated from either nasal swabs or milk, from sheep and goats in different regions of Jordan. The antimicrobial susceptibility showed some Mycoplasma species-specific differences, with M. capricolum subsp. capricolum being more susceptible to tylosin and erythromycin. Chloramphenicol and florfenicol were the least effective for all three Mycoplasma species. No trends or significant differences in antimicrobial susceptibilities were observed between sheep and goat isolates, between milk or nasal swab isolates, or between isolates from different regions of Jordan. Some isolates of M. capricolum subsp. capricolum and M. putrefaciens showed higher MIC levels with oxytetracycline, as did two isolates of M. mycoides subsp. mycoides LC with tylosin, possibly indicating signs of development of antimicrobial resistance.     

Surveys on Coxiella burnetii infections in Swedish cattle,sheep, goats and moose

Background

Q fever is a zoonotic disease caused by the bacterium Coxiella burnetii. Prevalence data in ruminant species are important to support risk assessments regarding public and animal health. The aim was to investigate the presence of or exposure to C. burnetii in cattle, sheep, goats and moose, and to compare two enzyme-linked immunosorbent assays (ELISAs). National surveys of antibodies against C. burnetii were performed for dairy cattle (n=1537), dairy goats (n=58) and sheep (n=518). Bovine samples consisted of bulk milk, caprine of pooled milk, and ovine of pooled serum. Antibodies were investigated in moose samples (n=99) from three regions. A one-year regional cattle bulk milk survey was performed on the Isle of Gotland (n=119, four occasions). Cattle, sheep and goat samples were analysed with indirect ELISA and moose samples with complement fixation test. For the sheep, goat, and parts of the cattle survey, samples were run in parallel by ELISAs based on antigens from infected ruminants and ticks. Bulk milk samples from the regional cattle survey and vaginal swabs from a subset of the sheep herds (n=80) were analysed for the agent by polymerase chain reaction. Spatial clustering was investigated in the national cattle survey.

Results

The prevalence of antibodies in dairy herds was 8.2% with large regional differences. High risk clusters were identified in the southern regions. The prevalence among dairy herds on the Isle of Gotland varied from 55.9% to 64.6% and 46.4% to 58.9.0% for antibodies and agent, respectively, overall agreement between agent and antibodies was 85.2%. The prevalence of antibodies in sheep was 0.6%, the agent was not detected the vaginal swabs. Antibodies were not detected in goats or moose, although parts of the moose samples were collected in an area with high prevalence in cattle. The overall agreement between the two ELISAs was 90.4%.

Conclusions

The prevalence of antibodies against C. burnetii in dairy cattle in Sweden shows large regional differences. The results suggest that C. burnetii is a rare pathogen among Swedish moose, dairy goat and sheep. ELISAs based on ruminant and tick antigen performed in a similar manner under Swedish conditions.     

Helminths of sheep and goats in desert areas of south-west Mauritania (Trarza)

Faecal samples were obtained from sheep and goats before, during and after the rainy season at three locations in south-west Mauritania. Several animals were also necropsied at the same time.Haemonchus contortus was the most prevalent worm. Infection by digestive-tract strongyles andStrongyloides papillosus was always very light (prevalence less than 20%). Sheep were more heavily infected than goats but animals under 1 year of age were not infected by digestive-tract strongyles. It is likely that young small ruminants became infected during the rainy season and that the parasites so acquired are inhibited in their development and/or survive nearly one year as adults.     

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 bi-monthly 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.     

Gastrointestinal helminths and lungworms of French dairy goats: Prevalence and geographical distribution in Poitou-Charentes

A study was conducted on 81 dairy-goat farms in western France. Faecal samples were collected once and 31 culled goats were necropsied in order to assess their gastrointestinal and respiratory helminth species, their prevalences and the intensities of infection as well as their geographical distribution in six subregions of the surveyed area. Fifteen species of helminth were recovered. The most frequent wereMuellerius capillaris, Trichostrongylus colubriformis andTeladorsagia circumcincta with a prevalence more than 90%. The two latter species represented respectively 50.9% and 30.2% of the total worm burden of the digestive tract. Other prevalent species wereHaemonchus contortus, Strongyloides papillosus, Trichuris spp.,Moniezia spp. andDicrocoelium lanceolatum. The occurrence ofDicrocoelium lanceolatum was related to the presence of calcareous or alkaline soils and restricted to the south of the surveyed area. No area at particular risk was defined for the other helminth infections, probably because of the relative homogeneity in climatic and topographic conditions of the six agricultural regions.     

Performance and nematode infection of ewe lambs on intensive rotational grazing with two different cultivars of <Emphasis Type="Italic">Panicum maximum</Emphasis>

The daily live weight gain (DLWG), faecal nematode egg counts (FEC), and packed cell volume (PCV) of Suffolk, Ile de France and Santa Inês ewe lambs were evaluated fortnightly for 56 days in the dry season (winter) and 64 days in the rainy season (summer) of 2001-2002. The animals were distributed in two similar groups, one located on Aruana and the other on Tanzania grass (Panicum maximum), in rotational grazing system at the Instituto de Zootecnia, in Nova Odessa city (SP), Brazil. In the dry season, 24 one-year-old ewe lambs were used, eight of each breed, and there was no difference (p > 0.05) between grasses for DLWG (100 g/day), although the Suffolk had higher values (p < 0.05) than the other breeds. In the rainy season, with 33 six-month-old ewe lambs, nine Suffolk, eight Ile de France and 16 Santa Inês, the DLWG was not affected by breed, but it was twice as great (71 g/day, p < 0.05) on Aruana as on Tanzania grass (30 g/day). The Santa Inês ewe lambs had the lowest FEC (p < 0.05) and the highest PCV (p < 0.05), confirming their higher resistance to Haemonchus contortus, the prevalent nematode in the rainy season. It was concluded that the best performance of ewe lambs on Aruana pastures in the rainy season is probably explained by their lower nematode infection owing to the better protein content of this grass (mean contents 11.2% crude protein in Aruana grass and 8.7% in Tanzania grass, p < 0.05) which may have improved the immunological system with the consequence that the highest PCV (p < 0.05) observed in those animals.     

The Prevalence and Intensity of Helminth and Coccidial Infections in Dairy Cattle in Central Kenya

A survey of gastrointestinal parasite infections of young (<6 months old), immature (6–12 months old) and adult (>12 months old) dairy cattle on 16 farms in Kiambu District, Kenya was conducted during a dry season (September 1991 to January 1992) and during a wet season (March to July 1992). The survey was based on monthly coproparasitological examination of cohorts and worm counts in tracer calves. The effects of age, sex, farm and season on the prevalence and intensity of helminth and coccidial infections were determined. Faecal egg and oocyst counts revealed that the overall prevalences were: strongyles (including trichostrongyles) (85.5%), liver flukes (Fasciola gigantica) (34.0%), coccidia (30.9%) and tapeworms (9.6%). Eight species of the protozoan Eimeria were identified, the most prevalent species being E. bovis and E. zuernii. The most prevalent nematode genera were Haemonchus, Cooperia, Oesophagostomum and Trichostrongylus. Season, farm and age of the animals had a significant (p<0.05) influence on the intensity of infection with strongyles, liver flukes and coccidia, whereas the sex of the animals had no significant (p>0.05) effect on the prevalence or intensity of infections. A higher intensity of infection with strongyles and coccidia was found in the wet season than in the dry season (p<0.05). The age-specific intensity was in the following order: for strongyles, immature animals of 6–12 months of age had the highest egg counts, followed by young calves and adults. Calves had significantly (p<0.05) higher oocyst counts than immatures or adults. Liver fluke egg counts did not differ significant (p>0.05) between immatures and adult cattle.