Spatial analysis of the exposure of dogs in rural north-coastal California to vectorborne pathogens.

Between 0 and 50 per cent of the dogs in eight rural villages in far northern California with a high risk of tickborne diseases were seropositive for Anaplasma phagocytophilum and Bartonella vinsonii subspecies berkhoffii, and between 0 and 10 per cent were seropositive for Borrelia burgdorferi. The odds ratio for the co-exposure of individual dogs to B vinsonii berkhoffii and A phagocytophilum was 18.2. None of the diseases was associated with the sex of the dogs, whether they slept out of doors, or whether tick-preventive measures were taken. When the villages were assessed for landscape risk factors, a particularly high seroprevalence for B vinsonii berkhoffii and A phagocytophilum was observed in a village at a relatively high altitude and greater distance from the Pacific coast, and montane hardwood conifer woodland was most associated with a high seroprevalence for these two pathogens.

Malassezia species isolated from the intermammary and preputial fossa areas of horses.

BACKGROUND: Malassezia-type yeasts previously have been observed on cytologic examination of the intermammary region of mares that presented with tail-head pruritus; topical antiyeast treatment resolved the pruritus. Further, Malassezia dermatitis has been observed in horses in intertriginous areas such as the udder and prepuce; the species of yeast was not confirmed. It is not known whether healthy mares or male horses can be carriers of this yeast in these body areas. HYPOTHESIS: Malassezia spp. are present in the intermammary region in healthy mares and the preputial fossa in healthy geldings. ANIMALS: Eleven healthy horses (5 mares and 6 geldings). METHODS: Samples of surface material were taken digitally from the intermammary area of 5 mares and the preputial fossa region of 6 geldings. The samples were examined cytologically and were cultured on modified Sabouraud's dextrose agar. The DNA from yeast colonies grown on the agar was extracted, and samples were assayed using fungal generic polymerase chain reaction (PCR) analysis. Amplicons with positive PCR results were sequenced and compared with sequences in the BLAST database search program. RESULTS: Of 44 attempts at culture, 5 yielded a species identified as Malassezia equi, and 2 yielded M slooffiae. In contrast, of 44 cytologic examinations, yeasts with the morphology of Malassezia spp. were seen in 40 samples. CONCLUSIONS AND CLINICAL IMPORTANCE: Due to its presence in healthy horses, finding of Malassezia-type yeast on cytologic examination may not incriminate it as a pathogen. Despite difficulty in culturing, cytologic examination was an effective tool to rapidly demonstrate the organism.