Dynamics of exposure to Rickettsia parkeri in cattle in the Paraná River Delta, Argentina

MONJE LD, COSTA FB, COLOMBO VC, LABRUNA MB, ANTONIAZZI LR, GAMIETEA I, NAVA S, BELDOMENICO PM.

JOURNAL OF MEDICAL ENTOMOLOGY

ENTOMOLOGICAL SOC AMER

Lugar: Lanham; Año: 2016 vol. 53 p. 660 - 665

0022-2585

Several cases of human rickettsiosis caused by Rickettsia parkeri were recently documented in the Parana Riverdelta of Argentina, where the tick vector is Amblyomma triste Koch. As cattle suffer recurrent A. triste infestations,they are at risk of becoming infected with R. parkeri. Herein we investigated the dynamics of R. parkeriand its A. triste vector in a herd of beef cattle. Cattle were followed for 18mo and samples were analyzed for thepresence of antibodies against four Rickettsia species (R. parkeri, Rickettsia bellii, Rickettsia amblyommii, andRickettsia felis) and also for the presence of rickettsial DNA. Additionally, cattle were examined for attachedticks and questing adult ticks were collected. All ticks were analyzed for the presence of rickettsial DNA. No evidenceof rickettsemia was found in any cow, but the high R. parkeri infection rate documented in A. triste bothquesting in the study area (13.9%) and feeding on cattle (19.8%) and the identification of antibodies againstR. parkeri antigen in 90% of cattle are evidence that infection is taking place. Altogether, our data suggest thatA. triste ticks are capable of naturally exposing cattle to R. parkeri. However, the progress of R. parkeri infectionand its impact on bovine health and production remain to be established.