Presence of<i> Rickettsia</i> Species in a Marginalized Area of Yucatan, Mexico

Abstract

In the state of Yucatan, Mexico, rickettsiosis has become a common vector-borne disease in the general population. Ectoparasite species such as <i>Rhipicephalus sanguineus</i> and <i>Amblyomma mixtum</i> have been identified as <i>Rickettsia</i> vectors in Yucatan by studies focused on the wild animal population in rural areas. There have been studies that have tried to determine the presence of <i>Rickettsia</i> species in ectoparasites collected in Yucatan, but these studies did not include marginalized areas, where living in close contact with domestic and peridomestic animals that carry ectoparasites is a high-risk factor for acquiring rickettsial infection or many other vector-borne diseases. We evaluated the vector diversity and the presence of <i>Rickettsia</i> species presence in the ectoparasite population that parasitizes domestic animals in a marginalized rural town of Yucatan, Mexico; we also evaluated the seroprevalence of rickettsial antibodies in the human population of this town in order to determine the prevalence of rickettsial infection. A total of 437 ectoparasites were collected from the study area. The tick specimens collected belonged to the species <i>Rhipicephalus sanguineus</i> (n=380, 49 positive), <i>Amblyomma mixtum</i> (n=3, 0 positive), <i>Ixodes affinis</i> (n=4, 0 positive), <i>Ctenocephalides felis</i> (n=33, 0 positive), and <i>Trichodectes canis</i> (n=17, 0 positive). Conventional polymerase chain reaction and sequencing were used to identify the DNA of <i>Rickettsia</i>. Six out of 354 (1.8%) serum samples were positive for antibody to <i>R. typhi</i>. The combination of low antibody titers and the presence of <i>Rickettsia</i> species infecting ectoparasite species found in the study area requires eco-epidemiological studies and the identification of potentially protective practices or habits.