Survey of pyrethroid and organophosphate resistance in Brazilian field populations of Rhipicephalus (Boophilus) microplus: detection of C190A mutation in domain II of the para-type sodium channel gene.

The cattle tick Rhipicephalus (Boophilus) microplus causes expressive damage to livestock in Brazil and other countries. Its control is becoming more difficult due to the development of resistance in populations. Early detection of resistance can help in developing effective control strategies.

Detection of bacteria related to Candidatus Midichloria mitochondrii in tick cell lines.

Many ticks have been shown to be infected with intracellular bacteria. One of these bacteria is Candidatus Midichloria mitochondrii which is the only characterized bacterium that has the ability to invade the mitochondria within ovarian cells and consume them without any effect on the female tick's reproduction. In the present study, eight cell lines derived from the ticks Ixodes ricinus, Ixodes scapularis, Rhipicephalus (Boophilus) microplus, and Rhipicephalus (Boophilus) decoloratus were examined for the presence of the bacterium Ca.

Use of refrigeration as a practical means to preserve viability of in vitro-cultured IDE8 tick cells.

In vitro cultivation of the IDE8 cell line, derived from embryonic Ixodes scapularis ticks, constitutes an important system for the study of tick-borne pathogens, as these cells support growth of rickettsial species which are not normally transmitted by this tick. However, since cryopreservation of IDE8 cells is not always successful, there is a need to develop alternative ways to preserve these cells. In the present study, a suspension of IDE8 cells in culture medium was kept under refrigeration at 4 degrees C for up to 60 days.

Lack of infectivity of a Brazilian Anaplasma marginale isolate for Boophilus microplus ticks.

Previous studies have shown that one Brazilian Anaplasma marginale isolate presents an inclusion appendage (tail), while other isolates do not present such inclusion. Studies on tick transmission have been carried out with tailless isolates but little is known about transmission of tailed isolates by Boophilus microplus. Two splenectomized calves were experimentally inoculated with the tailed A.

Phylogeography of New World isolates of Anaplasma marginale based on major surface protein sequences.

Gene and protein sequences of major surface proteins (MSP) 1a and 4 of Anaplasma marginale (Rickettsiales: Anaplasmataceae) were used to infer phylogenetic relationships between New World isolates from Argentina, Brazil, Mexico and the United States. Seventeen isolates of A. marginale plus two outgroup taxa (A.