Confirmation of hemoplasmas in Linognathus setosus (vol Olfers, 1816) (Psocodea: Anoplura: Linognathidae) infesting domestic dogs in Mexico City, Mexico

Ectoparasites pose significant health challenges for pets by causing dermatological conditions that lead to intense itching, potentially resulting in secondary bacterial and/or fungal infections. Additionally, many ectoparasite species act as vectors for bacterial and parasitic pathogens or serve as intermediate hosts for helminths. Despite their medical importance, certain groups of ectoparasitic insects, such as lice, are rarely reported. During a routine medical examination in Tláhuac, Mexico City, the presence of the sucking louse Linognathus setosus was morphologically and molecularly confirmed on two domestic dogs. Seventy lice (55 females, 10 males, and 5 nymphs) were collected. Sequencing of a 650-bp fragment of the cytochrome oxidase subunit 1 (COI) gene revealed a 98% similarity to the only two available L. setosus sequences, from Canada and Norway. Additionally, Mycoplasma haemocanis was detected in two of the analyzed specimens. This finding provides valuable data on the distribution of ectoparasites in urban environments in Mexico. Further research is recommended to assess the prevalence and potential pathogenic role of L. setosus in urban canine populations.