First report of Trypanosoma microti in Cricetid rodents from Querétaro, Mexico: Expanding the known distribution of Herpetosoma in the Mexican transition zone.

Members of the subgenus Herpetosoma are specialized parasites of mammals of the order Lagomorpha and Rodentia. It is estimated that around 50 species within this subgenus are transmitted by several flea species. These parasites have recently gained attention from a public health perspective because several species have been reported to infect humans. Several species of the Herpetosoma subgenus have been recognized on the American continent, although there have been no reports from the Mexican Transition Zone. Therefore, the present study aimed to report the presence of a member of the Herpetosoma subgenus in cricetid rodents from Querétaro, Mexico. A total of 17 rodents belonging to three species, Peromyscus boylii, Peromyscus gratus, and Peromyscus melanophrys, were collected. Genetic material was extracted using the Chelex 100 resin, followed by PCR and sequencing of a fragment of 800 bp of the 18S ribosomal gene of the genus Trypanosoma. Out of these hosts, eight individuals of P. gratus (1♀), P. melanophrys (1♂), and P. boylii (3♂, 3♀) tested positive for Trypanosoma microti DNA, previously detected in the England and Japan. The present study, therefore, provides the first discovery of T. microti in Mexico, thereby increasing the known richness of species of the genus Trypanosoma in rodents from this country and the Mexican Transition Zone.