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

A

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

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

Efficacy of a new spot-on formulation of selamectin plus sarolaner against Ancylostoma tubaeforme and Toxocara cati in cats

The efficacy of a new spot-on formulation of selamectin plus sarolaner for cats was evaluated against induced infections with Ancylostoma tubaeforme (hookworm) and Toxocara cati (roundworm). Five laboratory studies were conducted using adult, purpose-bred cats. Four of the studies were designed to evaluate efficacy of the combination against A. tubaeforme, the dose-limiting gastrointestinal nematode species for selamectin. In two of these studies non-interference between selamectin and sarolaner was also evaluated. The fifth study evaluated efficacy of the combination against mixed infections of A. tubaeforme and T. cati. The hookworm isolates in three studies were of US origin, as was the roundworm isolate. In the two remaining studies, cats were inoculated with a hookworm isolate of European origin. Cats were inoculated with 150 (±50) to 200 (±50) infective hookworm larvae 30–42 days prior to treatment and with 400 infective roundworm eggs 60 days prior to treatment. Cats were ranked by pre-treatment faecal egg counts and randomly allocated to different treatment groups. In all studies, cats were treated at the minimum label dose to provide 6.0 mg selamectin per kg bodyweight. All animals were euthanized 7–10 days after treatment for worm counts. Efficacy was calculated based on the reduction of the geometric mean worm counts in the treated groups versus the placebo-treated control groups. The efficacy against adult hookworms was 99.2%, 94.3% and 100% in three of these studies, and was lower in the remaining two studies. The efficacy against T. cati was 100%. Furthermore, non-interference between sarolaner and selamectin was demonstrated. Thus, a single topical application of the new spot-on formulation of selamectin plus sarolaner at the minimum label dose is effective in the treatment of adult hookworm and roundworm infections in cats

Efficacy of a new spot-on formulation of selamectin plus sarolaner for cats against adult Ctenocephalides felis, flea egg production and adult flea emergence

A new spot-on formulation of selamectin plus sarolaner was evaluated against fleas for adulticidal efficacy, and for the effect on egg production and hatching when applied to flea-infested cats. Ten male and ten female adult domestic shorthair cats were randomly assigned to one of two treatment groups based on pre-treatment flea counts. Cats received topical treatment on Day 0 in a single spot to the dorsal scapular area with either a placebo formulation or with the combination formulation at the minimal dose of 6.0 mg selamectin plus 1.0 mg sarolaner per kg bodyweight. On Days −1, 5, 12, 19, 26 and 33, cats were infested with approximately 100 (±5) unfed Ctenocephalides felis fleas. At 24 h after treatment or 48 h after subsequent flea infestation, cats were housed for a 20-h period in a cage to allow collection of flea eggs. At the end of this period, flea eggs were collected from the cages and cats were combed to remove and count live fleas. Emerged viable larvae and emerged adult fleas were counted 3 days and 35 days, respectively, after egg collection. The new spot-on formulation of selamectin plus sarolaner provided 100% efficacy against adult fleas up to Day 36 following a single application. Fleas on placebo-treated cats produced large numbers of eggs throughout the study, with individual counts ranging from 110 to 1256 eggs. Following treatment, four flea eggs were collected from a single selamectin/sarolaner-treated cat on Day 29, but there were no eggs collected from any other selamectin/sarolaner-treated animal during the study. No larvae or adult fleas developed from these four eggs. From the eggs collected from the placebo-treated cats, the mean percentage of live larvae and adults that emerged ranged from 67.3% to 84.2% and from 50.7% to 81.8%, respectively. A single topical treatment with a new spot-on formulation of selamectin plus sarolaner at the minimum label dose thus controlled fleas on cats and was 100% effective in preventing flea reproduction for over one month after treatment