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We performed a phylogenetic analysis of caprine and ovine lentiviruses using long sequences in gag and pol of 104 new Swiss isolates and six available corresponding database sequences. Forty-five isolates, forming five sequence clusters, were unclassifiable by the present classification. Pairwise DNA distance analysis indicated different categories of relatedness, requiring a new classification system. We propose four principal sequence groups, A-D, which differ by 25-37%. Groups A and B are further divided into subtypes which differ by 15-27%. Group D and four of the seven group A subtypes, A3, A4, A5 and A7, are formed by new Swiss isolates. Molecular epidemiology revealed that Swiss B1 strains differed no more from French, Brazilian or US strains than from each other, suggesting virus propagation through international livestock trade. Furthermore, infection of goats by subtypes A3 or A4 was significantly associated with documented contact with sheep, which also harbor these subtypes, thus indicating regularly occurring sheep-to-goat transmission.

The incidence of a new, yet unassigned toxin type ofClostridium perfringens containing the genes for the α-toxin and the recently described β2-toxin in horses with intestinal disorders is reported. The study included 18 horses suffering from typical typhlocolitis, 7 horses with atypical typhlocolitis, 16 horses with other intestinal disorders, and 58 horses without intestinal disease. In total, 20 samples of ingesta of the small and large intestines, five biopsy specimens of the intestinal wall, and 74 fecal samples were analyzed bacteriologically. C. perfringens isolates were typed for the presence of the α-, β-, β2-, and ɛ-toxin and enterotoxin genes by PCR, including a newly developed PCR for the detection of the β2-toxin genecpb2. β2-Toxigenic C. perfringens was detected in samples from 13 of 25 (52%) horses with typical or atypical typhlocolitis, with a particularly high incidence in specimens of ingesta and biopsy specimens (75%), whereas only 6 of 16 specimens from horses with other intestinal diseases yielded β2-toxigenicC. perfringens. No β2-toxigenic C. perfringens was found in the samples from the 58 control horses, of which only one fecal sample contained C. perfringenstype A. Among the samples from the 15 horses with fatal cases of typical and atypical typhlocolitis 9 (60%) were positive for β2-toxigenic C. perfringens, whereas samples from only 4 of the 10 (40%) animals with nonfatal cases of infection were positive. We found an interesting correlation between the antibiotic-treated horses which were positive for β2-toxigenicC. perfringens and lethal progression of the disease. NoC. perfringens strains isolated in this study contained genes for the β- and ɛ-toxins and enterotoxin. The high incidence of β2-toxigenic C. perfringens in samples of ingesta, biopsy specimens of the intestinal wall, and feces from horses suffering or dying from typhlocolitis together with the absence of this organism in healthy horses provides strong evidence that β2-toxigenicC. perfringens play an important role in the pathogenesis of typhlocolitis.

The species Campylobacter fetus is divided into the subspecies C. fetus subsp. venerealis (CFV) and C. fetus subsp. fetus (CFF). CFV is the causative agent of bovine genital campylobacteriosis, a highly contagious venereal disease that may lead to serious reproductive problems, including sterility and abortion. In contrast, CFF can be isolated from the gastrointestinal tract of a wide range of host species, is associated with abortion in sheep and cattle, and can also be isolated from local and systemic infections in humans. Despite differences in host and niche preferences, microbiological differentiation of the two subspecies of C. fetus is extremely difficult. This study describes the identification of a new insertion element, ISCfe1, which is present exclusively in CFV strains, with highly conserved specific ISCfe1 insertion sites. The results are useful for identification and differentiation of the two C. fetus subspecies and will help in understanding the evolution and pathogenesis of C. fetus.

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