C. Bauer

Prevalence, risk factors and economic importance of infestations with Sarcoptes scabiei and Haematopinus suis in sows of pig breeding farms in Hesse, Germany

Abstract.  A cross‐sectional survey was performed in 110 randomly selected pig‐breeding farms of southern Hesse, Germany to estimate the prevalence of ectoparasite infestations and to find possible risk factors. Ear scrapings of, if available, 10 sows per farm were examined for Sarcoptes scabiei var. suis (De Geer) (Acaridida: Sarcoptidae) by the potassium hydroxide digestion method, and a total of 2754 sows was inspected for skin lesions and infestations with Haematopinus suis (L.) (Anoplurida: Haematopinidae). Data on farm profiles and sows were collected by a questionnaire. In total, 19.1% and 2.5% of the sows were found to be infested with S. scabiei or H. suis, respectively. The percentage of mite or louse infestation was significantly higher in sows showing pruritus than in those without skin lesions. Both ectoparasite infestations were related neither to the age of sows nor their reproduction status, nor to the time interval to last ectoparasite treatment. Using farms as the unit of analysis, the estimated prevalence of mange mite and louse infestations was 45.4% and 14.5%, respectively. There was no significant association between the presence of S. scabiei and H. suis in the farms. Risk factors for S. scabiei infestation were mixed housing of dry and nursing sows in the same unit (vs. separate housing) and straw bedding (vs. strawless). For louse infestation, only mechanical cleaning of stable units (vs. additional use of disinfection methods) and pasturing of gilts and dry sows were identified as risk factors. The economic loss by S. scabiei infestation in the study population was assessed at €4200 per affected farm and year on average.

In vitro cultivation of Hammondia heydorni: Generation of tachyzoites, stage conversion into bradyzoites, and evaluation of serologic cross-reaction with Neospora caninum

Hammondia heydorni was in vitro isolated from oocysts shed by three dogs using a finite cell line from embryonal bovine heart (KH-R). The oocysts were purified and suspended in 2% potassium dichromate or 2% sulphuric acid for sporulation for 2-5 days at room temperature. The parasites were confirmed as H. heydorni by PCR using specific primers (JS4/JS5) and by negative reaction for Neospora caninum employing the primers Np6+/Np21+. H. heydorni sporulated oocysts (1 × 10(6)) from each dog were initially treated with sodium hypochlorite. For excystation of sporozoites, oocysts from one dog were lysed by ultrasound followed by incubation with 0.75% taurocholate. Excystation of sporozoites from the other two dogs was achieved by oocyst fragmentation with glass beads with no further chemical treatment. Tachyzoites were clearly seen in the cultures at three days post inoculation (dpi). Bradyzoite conversion and cyst formation were evaluated at different time points by using a polyclonal rabbit serum against a bradyzoite-specific antigen (anti-BAG1), and a rat monoclonal antibody (mAbCC2) against a cyst wall protein. Bradyzoites were firstly detected at 7 dpi. Between 18 and 21 dpi most of cultured parasites consisted of encysted bradyzoites. The H. heydorni cysts increased in size during cultivation and reached a length of up to 135 μm. The parasite was maintained in the bovine heart cells up to 4.5months. Sera from mice and sheep experimentally infected with H. heydorni oocysts reacted with H. heydorni by IFAT, but did not cross-react with N. caninum antigens using IFAT or immunoblot. These findings suggest that serological cross-reactivity between H. heydorni and N. caninum seems to be of minor importance.

Neospora caninum in dairy herds in Schleswig-Holstein, Germany.

The aim of a cross-sectional survey performed between November 2005 and April 2006 was to obtain actual information on the occurrence of Neospora (N.) caninum infection in dairy cows of Schleswig-Holstein. It was planned to examine tank-milk of about 35% of the approximately 6,000 dairy herds in Schleswig-Holstein for N. caninum-specific antibodies using a p38-tank-milk ELISA. This test is able to detect a within-herd N. caninum-seroprevalence of > 10%. Only 20 (1.0%) out of 1,950 tank-milk samples from Schleswig-Holstein reacted N. caninum-positive. A significantly higher proportion of positive herds came from districts with a human population density > 125 per km2 (P = 0.022, Fisher exact test). These districts were located close to the city of Hamburg. A prior survey in Rhineland-Palatinate performed with the same ELISA had revealed a proportion of 7.9% of tank-milk-positive herds. The results of the present survey therefore confirm prior assumptions that N. caninum infections are variably distributed in different German federal states. Similar to the results obtained in Rhineland-Palatinate, the observation of positive herds in the present study was associated with an elevated population density.