Medical and Veterinary Entomology

Abstract In northeastern Argentina, wild canids such as the pampas fox ( Lycalopex gymnocercus ) and the crab‐eating fox ( Cerdocyon thous ) coexist with domestic dogs ( Canis lupus familiaris ) across rural and peri‐urban landscapes, creating opportunities for tick and pathogen exchange. Characterizing tick assemblages and associated pathogens in these hosts is essential to assess potential public health risks at the wildlife–domestic interface. Ticks were collected opportunistically from domestic dogs and road‐killed foxes near two protected areas in Corrientes Province. Specimens were identified using morphological and molecular approaches and screened for Rickettsia spp. by PCR. A total of 30 adult ticks were obtained from 12 dogs and 8 foxes, representing four species: Amblyomma tigrinum , A. ovale , A. dubitatum and Rhipicephalus sanguineus . Amblyomma tigrinum was the most frequent species (50%). Seven individual ticks were confirmed as Candidatus Rickettsia andeanae in A. tigrinum , while one pooled sample was positive by screening only and was not confirmed. These findings expand the known geographic distribution of Ca. R. andeanae and provide molecular evidence of its circulation in ticks collected from both wild and domestic canids in northeastern Argentina. Our results highlight the importance of these hosts as sentinels for tick‐borne pathogens and underscore the need for integrated One Health surveillance to better anticipate emerging potential risks in interface areas.

Abstract Culicoides biting midges (Diptera: Ceratopogonidae) are vectors responsible for the transmission of several viruses of veterinary importance. Previous screens of Culicoides have described the presence of the endosymbiont Candidatus Cardinium hertigii (Bacteroidetes). However, any impacts of this microbe on vectorial capacity, akin to those conferred by Wolbachia in mosquitoes, are yet to be uncovered and await a suitable system to study Cardinium ‐midge interactions. To identify potential candidate species to investigate these interactions, accurate knowledge of the distribution of the endosymbiont within Culicoides populations is needed. We used conventional and nested PCR assays to screen Cardinium infection in 337 individuals of 25 Culicoides species from both Palearctic and Afrotropical regions. Infections were observed in several vector species including C. imicola and the Pulicaris complex ( C. pulicaris , C. bysta , C. newsteadi and C. punctatus ) with varying prevalence. Phylogenetic analysis based on the Gyrase B gene grouped all new isolates within ‘group C’ of the genus, a clade that has to date been exclusively described in Culicoides . Through a comparison of our results with previous screens, we suggest C. imicola and C. sonorensis represent good candidates for onward study of Cardinium‐ midge interactions.

Abstract Rickettsia are obligate intracellular pathogens transmitted by arthropod vectors. The re‐emergence of several rickettsioses imposes severe global health burden. In addition to the well‐established rickettsial pathogens, newer rickettsial species and their pathogenic potentials are being uncovered. There are many reports of spotted and typhus fever caused by rickettsiae in India. Hence, in this study we screened the ectoparasites of pet and domestic animals for the presence of rickettsia using polymerase chain reaction. Nine cat flea samples ( Ctenocephalides felis felis ), that tested positive for the presence of rickettsia were subjected to Multi Locus Sequence Typing. Nucleotide sequencing and Phylogenetic analysis of gltA, ompB and 16rrs genes revealed that the rickettsiae detected in cat fleas was Rickettsia asembonensis . Further studies are required to assess Rickettsia asembonensis pathogenic potential to human and its enzootic maintenance of in various hosts and vectors.