Clonal cultures of Histomonas meleagridis, Tetratrichomonas gallinarum and a Blastocystis sp. were established for the first time. Single microbes were successfully isolated from a mixture of micro-organisms obtained from caecal contents of turkeys, using a micromanipulation approach. The cloned parasites were propagated in vitro and maintained through continuous passages multiplying to high numbers. Identification of the protists was done by morphological investigation identifying various forms of each parasite. PCR and partial sequencing of the small subunit rRNA were used to confirm clonality and to determine the relationship of the cloned parasites with known protozoan parasites. The clonal cultures established by this technique will be useful to gain more insight into the biological repertoire of the organisms. In addition, refined infection experiments in different poultry species can now be performed to elucidate the pathological pathways of the respective protozoa.

Nationwide surveys for the occurrence of Isospora suis were carried out in Germany, Austria and Switzerland including a questionnaire regarding herd size, health status and management practices and a coccidiosis sampling kit for pooled faecal samples from litters of suckling piglets. A total of 184 veterinary practices participated in the survey and returned 1745 samples (331 kits) from 324 farms in the north (n = 98), south (n = 84), centre/east (n = 42) and west (n = 10) of Germany, Austria (n = 61) and Switzerland (n = 29) with larger farms in north and centre/east (average number of sows: 270 and 500) and smaller ones in the south (95), Austria (60) and Switzerland (43). Larger farms tended to have better hygienic standards (slatted floors, disinfection of the farrowing units). The majority of the participating farms (93.5%) reported problems with diarrhoea in piglets at 2-3 weeks of age, significantly associated (P < 0.001) with uneven weaning weights (94.9%). Toltrazuril (5%; Baycox) was used only rarely; however, in these farms unevenness of weaning weights was less frequently observed (P = 0.011). A 76.2% of the farms were positive for I. suis (samples contained mostly low or moderate oocyst numbers), especially in the south (P < 0.001). Oocysts were more frequently found in samples from farms with reported diarrhoea (P = 0.011), uneven weight gain (P = 0.019) or in herds of small size (P < 0.001). Disinfection, floor type or treatment with toltrazuril did not affect the frequency of observation of oocysts.

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Isospora spp. are the causative agents of canine isosporosis. Of the 3590 diagnostic samples from Austrian dogs (< or = 2 years old), 8.7% contained Isospora oocysts, 78% of which from dogs up to 4 months of age. Non-haemorrhagic and haemorrhagic diarrhoea were significantly more prevalent in Isospora-infected animals than in coccidia-negative ones. Twelve of 15 litters from a large commercial dog breeding unit (examined from the third to the 10th week of life) also excreted Isospora (average prevalence: 36.4%) in intensities from 333 to 35,000 oocysts per gram of faeces (opg). In experimental trials 26 3-week-old Beagle puppies were infected with low (600-6000), medium (10,000) or high (20,000) dose of Isospora ohioensis-group or Isospora canis field isolates. Additionally 21 puppies were infected as above and treated with a symmetrical triazintrione. Parasitological and clinical parameters were examined. The two Isospora species differed significantly concerning intensity and duration of excretion. The pre-patent period was 6-7 days for I. ohioensis and 10-12 days for I. canis. The latter species showed significantly longer excretion and higher opg. This was not influenced by simultaneous infections with both species. Individual patterns of faecal consistency were very variable, irrespective of the infection dose. Treatment significantly reduced both the intensity and the duration of oocysts excretion as well as diarrhoea in comparison with the infected, untreated group and thus proved to be effective against coccidiosis in experimental infections.

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