Cryptosporidium and Giardia in calves in Belgium

Cryptosporidiosis mainly occurs in calves younger than 1 month, and causes a mild to profuse diarrhea. In contrast, a Giardia infection is most frequently diagnosed in calves older than 1 month and clinical symptoms comprise a chronical and intermittent diarrhea, and ill thriving. Cattle are considered as a possible reservoir for zoonotic transmission. The objectives of the present thesis were to estimate the prevalence of both parasites in calves younger than 10 weeks, to evaluate common diagnostic techniques, to molecularly identify the parasite isolates, and to study treatment and control of giardiosis in calves. The prevalence of Giardia in dairy calves was 22% (95% CI: 12-34%) and in beef calves 45% (95% CI: 30-64%). The Cryptosporidium prevalence was estimated to be 37% (95% CI: 7-70%) in dairy and 12% (95% CI: 1-30%) in beef calves. Furthermore, 48% of the dairy and 64% of the beef farms had at least one Giardia positive calf, and 32% of the dairy and 24% of the beef farms had at least one Cryptosporidium positive calf. The Bayesian test evaluation indicated that some are both sensitive and specific diagnostic techniques for use in epidemiological studies, whereas others are less sensitive. The molecular identification revealed that the majority of the Cryptosporidium positive samples from dairy and beef calves was C. parvum, mainly the zoonotic subgenotype IIaA15G2R1. In the Giardia positive calf samples a high prevalence of infections with the zoonotic assemblage A was found. Furthermore, mixed assemblage A/E infections were identified using a new assemblage specific PCR, based on the triose phosphate isomerase gene. The identification of zoonotic lineages in the majority (for Cryptosporidium) or in a substantial part (for Giardia) of their parasite population indicate that dairy and beef calves are a potential zoonotic reservoir for human infections. The treatment and control of clinical giardiosis was studied in an experimental study to evaluate the efficacy of paromomycin sulphate, and in a field efficacy study to evaluate a combination of treatment with fenbendazole and environmental measures. Both paromomycin and fenbendazole significantly reduce cyst excretion, although in natural conditions environmental measures have to be applied

The prevalence and molecular characterisation of Cryptosporidium spp. in small ruminants in Zambia

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Evaluatie van twee intensieve behandelingsschema's tegen Psoroptes ovis-schurft bij Belgisch witblauwe runderen op negen Vlaamse rundveebedrijven

Psoroptic mange, caused by Psoroptes ovis, is a problem on many Flemish farms where Belgian blue beef cattle are bred. Two intensive treatment schedules were evaluated on nine Belgian blue fauns with a-persistent mange problem. On farms 1 to 7, all animals were treated twice (with a seven-to-ten-days interval) with an injectable macrocyclic lactone (ML), while on the two remaining fauns, the initial treatment consisted of one injection with the long acting (LA) formulation of moxidectin (10%). Skin scrapings were taken after treatment, and when living mites were found on at least one animal, all animals (farms 1 to 7) or only positive animals (farms 8 and 9) were treated consecutively with an injectable ML. On all farms, the treated animals were clinically healthy and P ovis free at the end of winter, after two to nine treatment rounds (two injections with a seven to ten-days interval or one LA injection). Although mange reappeared on the first seven farms after the subsequent grazing season, the disease was less severe and easier to control

Occurrence and potential health risk of Cryptosporidium and Giardia in different water catchments in Belgium

Human wastewater and livestock can contribute to contamination of surface water with Cryptosporidium and Giardia. In countries where a substantial proportion of drinking water is produced from surface water, e.g., Belgium, this poses a constant threat on drinking water safety. Our objective was to monitor the presence of Cryptosporidium and Giardia in different water catchment sites in Belgium and to discriminate between (oo) cysts from human or animal origin using genotyping. Monthly samples were collected from raw water and purified drinking water at four catchment sites. Cryptosporidium and Giardia were detected using USEPA method 1623 and positive samples were genotyped. No contamination was found in purified water at any site. In three catchments, only low numbers of (oo) cysts were recovered from raw water samples (<1/liter), but raw water samples from one catchment site were frequently contaminated with Giardia (92 %) and Cryptosporidium (96 %), especially in winter and spring. Genotyping of Giardia in 38 water samples identified the presence of Giardia duodenalis assemblage AI, AII, BIV, BIV-like, and E. Cryptosporidium andersoni, Cryptosporidium suis, Cryptosporidium horse genotype, Cryptosporidium parvum, and Cryptosporidium hominis were detected. The genotyping results suggest that agriculture may be a more important source of surface water contamination than human waste in this catchment. In catchment sites with contaminated surface water, such as the Blankaart, continuous monitoring of treated water for the presence of Cryptosporidium and Giardia would be justified and (point) sources of surface water contamination should be identified