First report of caprine abortions due to Chlamydia abortus in Argentina.

Infectious abortions of goats in Argentina are mainly associated with brucellosis and toxoplasmosis. In this paper, we describe an abortion outbreak in goats caused by Chlamydia abortus. Seventy out of 400 goats aborted. Placental smears stained with modified Ziehl-Neelsen stain showed many chlamydia-like bodies within trophoblasts. One stillborn fetus was necropsied and the placenta was examined. No gross lesions were seen in the fetus, but the inter-cotyledonary areas of the placenta were thickened and covered by fibrino-suppurative exudate. The most consistent microscopic finding was found in the placenta and consisted of fibrinoid necrotic vasculitis, with mixed inflammatory infiltration in the tunica media. Immunohistochemistry of the placenta was positive for Chlamydia spp. The results of polymerase chain reaction targeting 23S rRNA gene performed on placenta were positive for Chlamydia spp. An analysis of 417 amplified nucleotide sequences revealed 99% identity to those of C. abortus pm225 (GenBank AJ005617) and pm112 (GenBank AJ005613) isolates. To the best of our knowledge, this is the first report of abortion associated with C. abortus in Argentina.

Metaphylactic effect of Diclazuril 0.25% in suckling beef calves, during a coccidiosis outbreak in extensive farming.

The weight gain performance and oocysts reduction, as response to the metaphylactic treatment with Diclazuril 0.25% at the start of a coccidiosis outbreak, was studied by a cases-controls transverse study. Fifty-eight suckling calves of approximately 90 days old were randomly selected from an infected beef herd on extensive farming. The calves were weighted and individual faecal samples were taken for oocyst per gram count (OPG). Out of those, 29 were drenched with 1 mg kg(-1) of Diclazuril in one oral dose (group T), since the other 29 remained as control group (group C). Samples for OPG and weights were measured again at days 7 and 21 after treatment, respectively. Later, the groups were divided (by the median) in higher or lower OPG counts, and were compared in the same way, in order to remove those without apparent infection (lower OPG counts). The faecal oocysts reduction reached 99.5% (p<0.0001), for the treated group. Along the three weeks of study, an increment of 2.65 kg in 21 days (125 g day(-1), p=0.036), was seen in treated group respect to controls, but this difference increased to 3.94 kg in 21 days (p<0.0001), when only the calves with higher OPG were taken into account. These results highlight the magnitude of the subclinical impact of coccidiosis, biased by the individual susceptibility to infection, which leads to get heavier infections and express higher oocysts output.