A cross-sectional study was carried out to determine the prevalence of gastrointestinal (GI) nematodes and flukes (Fasciola and amphistomes) infection in communally grazed traditional cattle, zero-grazed small-scale dairy cattle and intensively grazed large-scale dairy cattle through examination of helminth eggs in faeces. Results indicated that the type of management, especially the grazing habit, has a significant influence on the prevalence and intensity of GI nematodes and flukes. The prevalence of GI nematodes in traditional, large-scale dairy and small-scale dairy cattle was 67%, 44.4% and 37%, respectively, with the highest faecal egg counts in calves. The overall prevalence of Fasciola gigantica in traditional, large-scale dairy and small-scale dairy cattle was 63.8%, 46.2% and 28.4%, respectively. The prevalence of amphistomes was 81.9%, 55.5% and 41.1% in traditional, large-scale dairy and small-scale dairy cattle, respectively. The high prevalence of flukes in the traditional system was attributed to communal grazing and watering management practices. Stomach flukes recovered in examined cattle at the abattoir were Calicophoron microbothrium and Cotylophoron jacksoni. About 42.1% of infected animals had both Fasciola and amphistomes. The prevalence of both GI nematodes and flukes varied greatly among villages and farms. The prevalence of both Fasciola and amphistomes was higher in adults (58.5%, 75.2%) than in yearlings (36.5%, 51.5%) or calves (24.9%, 47.2%). The variation in the prevalence of both GI nematodes and flukes among management and age groups within systems can be used as an entry point towards rational use of anthelmintics for each management system. More studies on seasonal transmission pattern of all these parasites are required in order to design rational, economic and locally sustainable parasite control programmes.

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A longitudinal descriptive study was conducted to determine the prevalence and distribution of flukes (Fasciola gigantica and amphistomes) on traditional, large-scale and small-scale dairy cattle farms in Iringa district, southern highlands of Tanzania. Coprological examinations of different cohorts for the presence of fluke eggs were recorded monthly. Results indicated a significant influence of the type of management on the prevalence of both Fasciola and amphistomes. The prevalence of flukes was highest in the traditional system, moderate in the large-scale dairy system and lowest in the small-scale dairy system in most parts of the year. Adults and yearlings had the highest prevalence of flukes in all management systems throughout the year. The proportion of animals excreting amphistome eggs was always higher than that of animals excreting Fasciola eggs in all zones, villages, management systems, farms and age groups. The proportion of animals passing fluke eggs increased gradually from the early dry season and peaked at the end of the dry season and the early part of the rainy season. Strategic treatments against flukes are recommended in adults and yearlings only in traditional and large-scale dairy farms. Routine treatments of calves/weanlings in large-scale and traditional farms and zero-grazed small-scale dairy cattle farms might be unnecessary. For a cost-effective helminth control programme in the area, strategic treatments at the beginning of the dry season (June) and at the end of the dry/early rainy season (November/December) are recommended.

BackgroundAlthough Ascaris suum is the most common pig nematode, the on-farm transmission dynamics are not well described.MethodsWe performed a 1-year field study on five organic pig farms, mapping egg contamination levels in pens and pasture soil as well as faecal egg counts in starter pigs, finisher pigs, dry and lactating sows. The uppermost bedding material was sampled from three pen areas (resting, intermediate and latrine) of shallow and deep litter pens.ResultsAscaris suum was found on all farms. Averaged across farm and season, the prevalence of A. suum was 48, 64, 28 and 15 % in starters, finishers, dry and lactating sows, respectively. For starters and finishers, the prevalence varied with season increasing towards the end of the year when 83–96 % of finishing pigs from each farm had fresh liver white spots. Farrowing pastures were contaminated with a mean of 78–171 larvated eggs/kg dry soil depending on farm, while pastures for starter pigs contained 290–5397 larvated eggs/kg dry soil. The concentration of eggs in soil was highest in the autumn. Indoors, all pen areas were contaminated with A. suum eggs at comparable levels for shallow and deep litter. Overall there were 106, 445 and 1331 eggs/g dry straw in the resting, intermediate and latrine areas, respectively. However, more eggs were undergoing development in resting areas (44 %) compared to intermediate (33 %) and latrine areas (13 %). Irrespective of area, more eggs were undergoing development in the autumn, but overall there were very few fully developed (i.e., infective) eggs in the bedding material. Laboratory embryonation of eggs from the bedding material nevertheless revealed that an overall mean of 79 % of the eggs were viable.ConclusionThe organic pigs of all ages were continuously exposed to A. suum, but mainly younger animals were infected. Deep litter appeared to be a less important source of A. suum eggs than previously believed compared to shallow litter. Long-term pasture rotation to eliminate pasture contamination was not possible, and control programs should therefore include thorough cleaning indoors and composting/long-term storage of bedding material and manure to inactivate eggs and reduce transmission to pigs.