In vivo exposure of Albendazole sulphoxide by Haemonchus contortus and correlation between plasma and target tissue or gastrointestinal content dispositions in goats.

Sheep and goats are sharing different helminth parasites including Haemonchus contortus. Control of these helminths is based mainly on the use of anthelmintics. However, in goats, the application of anthelmintics is often carried out mainly at dosages determined for sheep without knowing the real effects and metabolism features. One of the several anthelmintic classes used against these parasites is (pro) benzimidazoles which are still widely in use in small ruminants in many countries. The objective of this study was to determine (i) the correlation between plasma and tissue or gastrointestinal content dispositions of ricobendazole (RBZ) in goats and (ii) the in vivo exposure of ricobendazole by H. contortus. Ten goats were experimentally infected with 10,000 larvae of H. contortus. Four weeks of post-infection, the animals received RBZ subcutaneously at 5 mg/kg body weight. Two goats were sacrificed per time at 1, 2, 4, 6 and 12 h after drug administration and, blood, bile, urine, liver, lung, muscle and kidney gastrointestinal tissues/fluids were collected. Adult H. contortus were collected from abomasum, and all samples were analysed by HPLC system. Ricobendazole (RBZ) and its sulphone metabolite were extensively excreted by urine and distributed to all tissues and digestive tract, mainly into the abomasum fluid. RBZ concentration in the lung and ABZSO2 in the kidney were relatively higher than those of other tissues, respectively. The parent drug and its metabolite were recovered in both male and female H. contortus. This study indicates that in goats the plasma concentration profiles of RBZ are strongly correlated with those achieved in different target tissues or fluids, which in turn, reflect the amount of drug taken up by parasites.

Ectoparasites of hedgehogs (Erinaceus concolor) from Turkey.

Hedgehogs are small, nocturnal, spiny-coated animals that have been growing in popularity as exotic pets. However, these animals are host to a wide variety of viruses, bacteria, fungi and parasites, some of which are of zoonotic character. Thus, because hedgehogs have a potential role to transmit zoonoses including arthropod-borne diseases, we examined them for their ectoparasites. The study was carried out on hedgehogs found dead mainly due to road casualties in the Bursa province of Turkey. The ectoparasites were collected by both insecticide spraying of the body and inspection on a white paper carefully. Totally three species of ticks (Rhipicephalus sanguineus, Hyalomma aegyptium, Haemophysalis parvo) and one flea species (Archeopsylla erinacei) were detected. The prevalence of mixed infestation with both ticks and fleas was 45.5%. Haemaphysalis parva was reported for the first time from hedgehogs (Erinaceus concolor) in Turkey. The occurrence of ectoparasites and their potential role as vectors of certain zoonotic diseases are briefly discussed.

Helminth parasites found in hedgehogs (Erinaceus concolor) from Turkey.

Hedgehog diseases are becoming important issues for veterinary surgeons due to growing interest in this animal species among pet owners and an increase in cases of rescued hedgehogs requiring veterinary care. A parasitological study was carried out on hedgehogs (Erinaceus concolor) in the Bursa province of Turkey, found dead mainly due to road casualties, to determine their helminth parasite burden. The detected helminths and their prevalences were as follows: Physaloptera clausa (72.2%), Crenosoma striatum (55.5%), Aonchotheca erinacei (55.5%), Hymenolepis erinacei (55.5%), Nephridiorhynchus major (50%) and Eucoleus aerophilus (22.2%). The number of parasites in infected animals varied from 1 to 203. The highest mean intensity of infection was observed with C. striatum, and the lowest was observed with N. major. The mean abundance of different species varied from 0.7 to 41.8, where E. aerophilus and C. striatum had the lowest and highest abundance, respectively. This study represents the first time N. major and E. aerophilus have been reported in hedgehogs in Turkey. The presence of E. aerophilus and its potential role as a zoonotic agent are discussed.

Comparative plasma disposition, bioavailability and efficacy of ivermectin following oral and pour-on administrations in horses.

Pour-on formulations of endectocides decrease the risk of injury for both user and animal, and are particularly convenient for animal owners who can apply the product. This study was designed to investigate the plasma disposition and efficacy of ivermectin (IVM) following pour-on, per os and intravenous administrations. Eighteen female horses weighing 510-610 kg were used in this study. The animals were allocated into three groups (per os, pour-on and intravenous groups). The equine paste, bovine pour-on and bovine injectable formulations of IVM were administered orally, topically and intravenously at the dose rates of 0.2, 0.5 and 0.2mg/kg bodyweight, respectively. Heparinized blood samples and hair samples were collected at various times between 1h and 40 days. The samples were analysed by high performance liquid chromatography with fluorescence detector. Faecal strongyle egg counts (EPG) were performed by a modified McMaster's technique before and at weekly intervals during 10 weeks after treatment. The results indicated that the plasma concentration and systemic availability of IVM was lower but the plasma persistence was prolonged after pour-on administration compared with per os route. IVM (paste) reduced the EPG by >95% for 10 weeks, whereas the reduction in pour-on group varied from 82 to 97%. EPG reduction in pour-on group was lower than that of per os group. Degradation on the application site, cutaneous biotransformation, binding of IVM to the haircoat and/or sebum are probably responsible for the relatively lower bioavailability of IVM in horses after pour-on administration. In conclusion, the poor plasma availability observed after pour-on administration could result in subtherapeutic plasma concentrations, which may promote the development of drug resistance in parasites.

Standardization of the egg hatch test for the detection of benzimidazole resistance in parasitic nematodes.

The ability to reliably detect anthelmintic resistance is a crucial part of resistance management. If data between countries are to be compared, the same test should give the same results in each laboratory. As the egg hatch test for benzimidazole resistance is used for both research and surveys, the ability of different laboratories to obtain similar results was studied through testing of known isolates of cyathostomins, Haemonchus contortus, Ostertagia ostertagi, and Cooperia oncophora in programs supported by the EU (Cost B16 and FP6-PARASOL). Initial results showed difficulties in obtaining reproducible and similar data within and between laboratories. A series of ring tests, i.e., simultaneous and coordinated rounds of testing of nematode isolates in different laboratories was subsequently performed. By adopting identical protocols, especially the use of deionized water and making dilutions of thiabendazole in dimethyl sulfoxide in the final ring test, laboratories correctly identified both susceptible and resistant isolates. The protocols for the test and preparation of solutions of thiabendazole are described.

[Occurrence and treatment of Bovicola (Damalinia) equi (Linnaeus, 1758) infestation on a thoroughbred horse farm.]. / Bir at çiftliginde Bovicola (Damalinia) equi (Linnaeus, 1758) enfestasyonu ve tedavisi.

Lice infestations of horses occur mainly during winter months and are characterized by severe pruritus and an unkempt coat. Two lice have been described for equines namely Bovicola (Damalinia) equi and Haemotopinus asini. There is a scarcity of data on the occurrence and prevalence rates of these horse pathogens in Turkey. This paper reports a thoroughbred farm, in which two horses were found to be infested with B. equi. The horses were treated with propoxur and no lice or nymphs could be found after treatment for10 days.

Comparison of conventional coproscopical methods and commercial coproantigen ELISA kits for the detection of Giardia and Cryptosporidium infections in dogs and cats.

Faecal samples of 270 dogs and 100 cats from 3 animal shelters in Germany were comparatively examined using conventional coproscopical methods and commercial coproantigen ELISA kits for the detection of Giardia and Cryptosporidium infections. Giardia cysts were found in 9.5% and 0% of the faecal samples in dogs and cats, respectively, examined once using the ZnCl2-NaCl flotation. However, the Giardia coproantigen ELISA (ProSpecT Giardia Microplate Assay) was positive in 29.5% and 22.4% of the samples from dogs and cats, respectively. Direct faecal smears stained with carbol fuchsin showed Cryptosporidium oocysts in one dog (0.4%) and one cat (1%). In contrast, the Cryptosporidium coproantigen ELISA (ProSpecT Cryptosporidium Microplate Assay) reacted positively in 23% of the samples from dogs and 30% of the samples from cats. Both coproantigen ELISAs were more often positive in coproscopically Giardia-negative canine faecal samples that contained Isospora burrowsi/ohioensis oocysts than in faecal samples without any parasite stage. Possible reasons for these observations are discussed.

Effects of Eimeria separata infections on Na+ and Cl- transport in the rat large intestine.

To study the pathophysiology of diarrhoea in coccidial infections, Na+ and Cl- fluxes (J(Na), J(Cl)), short circuit current (I(sc)) and tissue conductance (g(t)) were determined in stripped gut epithelia of Eimeria separata infected rats employing the Ussing chamber technique. E. separata invades enterocytes of the caecum and proximal colon. Na+ absorption was generally reduced in infected tissues, Cl- absorption only in the caecum. I(sc) values were increased in the caecum and reduced in the proximal colon. Tissue conductance was not affected. Values tended to normal with time after infection. Theophylline caused markedly increased I(sc) and g(t) values in the caecum epithelia of infected rats. In the epithelia of the distal colon, i.e. the non-infested part of the large intestine, g(t) values remained unaffected but I(sc) was fourfold increased. This I(sc) increase was strongly sensitive to amiloride, suggesting a compensatory activation of Na+ channels in the distal colon of infected rats. Accordingly, serum levels of aldosterone, which activates Na+ channels in the distal colon, were increased to eightfold levels in infected animals. Thus compensatory Na+ absorption was under endocrine control.