Haemaphysalis juxtakochi, Ixodes pararicinus (Ixodidae) and Otobius megnini (Argasidae) in relation to the phytogeography of Argentina.

The phytogeographical distributions of Haemaphysalis juxtakochi, Ixodes pararicinus and Otobius megnini in Argentina are described from material collected mainly from 1978 to the present. H. juxtakochi was found in the northwestern area of the Amazonian domain and in the Chaco, Espinal and Pampean provinces of the Chaco domain. It was detected on Mazama spp., Tapirus terrestris, dog, cattle and on the vegetation. Most findings of I. pararicinus were from mountain rangeland, where it was found on cattle and in a lesser extent on horses. Ticks from Argentina classified as Ixodes ricinus were probably I. pararicinus. O. megnini was detected on cattle an sheep in the Andean Patagonian domain and in the Monte, Chaco and Espinal provinces of the Chaco domain. This tick is considered typical of arid and semiarid conditions, however the findings from the Espinal province where from areas with an annual rainfall over 900 mm.

Antibody dynamics in Holstein Friesian heifers vaccinated with Brucella abortus strain 19, using seven serological tests.

The serological response induced by Brucella abortus strain 19 was evaluated in 52 Holstein females from a brucellosis-free herd using seven serological tests. Each calf was vaccinated at an age of 4 and 8 months old with 3 x 10(10) CFU B. abortus S19 and the antibody response was determined as the proportion of positive results to each test. The antibody dynamics, measured with the buffered plate antigen (BPA) test and the rapid automated presumptive (RAP) test, were similar. The proportion of positive reactions in these tests reached 100% one week after vaccination and remained at this level for seven weeks, after which the proportion of positive samples slowly declined to 8% (BPA) and 2% (RAP) at week 50. The response in the indirect enzyme immunoassay (i-ELISA) was similar, but shorter than that observed with the BPA/RAP. The antibody dynamic, measured using the seroagglutination test (SAT) in parallel with the 2-mercaptoethanol (2-Me) test and the complement fixation test (CFT) were similar to the RAP/BPA, but of slightly shorter duration. The competitive ELISA (c-ELISA) was positive in all animals for 3 weeks, followed by a rapid decline. The fluorescence polarization assay (FPA) reached a maximum of 68.5% positive animals at week 4 and then declined. Based on these data, the c-ELISA and FPA discriminated residual antibody activity due to vaccination more efficiently than the other tests.