Molecular detection of Rickettsia felis in fleas and ticks collected from dogs and cats of Puebla, Mexico

Abstract

Fleas and ticks represent the two main groups of ectoparasites that infest companion animals. In particular, the flea Ctenocephalides felis felis and several members of the Rhipicephalus sanguineus complex are the main vectors of a wide range of pathogens on the American continent. They are competent vectors for several members of the genus Rickettsia, which encompass at least 15 pathogenic obligate intracellular bacteria that colonize the endothelial cells of vertebrates. In Mexico, 10 species of Rickettsia belonging to three groups have been detected in six species of ectoparasites from dogs in 9 of the 32 states of the country. However, in some larger regions of the country, active epidemiological surveillance has not been carried out. For this reason, the aim of this study was to identify the presence of members of the genus Rickettsia in fleas and ticks of dogs and cats in the state of Puebla, Mexico. A cross-sectional study was carried out to collect ectoparasites of dogs and cats during August to November 2019. Samples were fixed in 70% ethanol and examined to identify the presence of Rickettsia DNA by the amplification and sequencing of specific fragments of the gltA and ompB genes using conventional PCR. The recovered sequences were compared with those deposited in GenBank, and phylogenetic analyses were carried out to identify the position of the pathogens detected with respect to the valid species previously reported worldwide. Additionally, ecological parameters of the ectoparasite infestations were also calculated. We recovered 196 ectoparasites belonging to two species, 33 C. felis felis and 163 R. sanguineus s.l. (Rhipicephalus linnaei), parasitizing 46 hosts (42 dogs and 4 cats) in 11 localities of the state of Puebla. We detected the presence of Rickettsia felis in three pools of C. felis felis, and five from R. sanguineus s.l. Our work provides the first record of R. felis in hard ticks of Mexico and Central America, with new collection localities for this pathogen in central Mexico.

Keywords: Ctenocephalides felis felis; Rhipicephalus sanguineus s.l.; emerging diseases; flea-borne rickettsiosis.