Assays to evaluate the transovarial transmission of Anaplasma marginale by Rhipicephalus microplus

CUTULLÉ, CHRISTIAN; SEBASTIAN, PATRICK STEPHAN; MAZZUCCO PANIZZA, MATILDE; MOREL, NICOLÁS; PRIMO, MARÍA EVANGELINA; NAVA, SANTIAGO

VETERINARY PARASITOLOGY

ELSEVIER SCIENCE BV

Año: 2022 vol. 311

0304-4017

The aim of this study was to evaluate the vectorial competence of Rhipicephalus microplus to transmit Anaplasmamarginale transovarially, by analyzing the results of three different but complementary assays. First, larvae ofR. microplus were fed on a calf infected with the isolate S1P of A. marginale. The engorged females obtained wereanalyzed by PCR and incubated for oviposition. After hatching, larvae were analyzed by PCR and fed on susceptiblesplenectomized cattle. Although A. marginale was detected in the females, no A. marginale DNA wasamplified from the larvae and transmission of A. marginale to cattle was not recorded. In the second experiment,R. microplus larvae were fed on cattle naturally infected with field isolates of A. marginale and experimentallyinfected with the isolate S1P of A. marginale. After detachment, engorged females were incubated for oviposition.The offspring were analyzed by PCR, with negative results. Finally, free-living larvae of R. microplus collectedfrom pasture on farms with cattle infected with A. marginale were analyzed by PCR for Anaplasma infection. Allsamples analyzed were negative for A. marginale. The results of this work indicate that transovarial transmissionof A. marginale by R. microplus is unlikely to occur.