Blood-feeding arthropods play a major role in the transmission of several flaviviruses, which represent an important problem for human health. Currently, dengue is one of the most important arboviral emerging diseases worldwide. Furthermore, some previous studies have reported the presence of viral nucleic acids and antibodies against dengue virus (DENV) in wild animals. Our knowledge of the role played by wildlife reservoirs in the sylvatic transmission and maintenance of DENV remains limited. Our objective was to screen blood-feeding ectoparasites (bat flies) and their common vampire bat (Desmodus rotundus) hosts, for flaviviruses in Hidalgo, Mexico. We detected Flavivirus sequences in 38 pools of ectoparasites (Diptera: Streblidae, Strebla wiedemanni and Trichobius parasiticus) and 8 tissue samples of D. rotundus by RT-PCR and semi-nested PCR using FlaviPF1S, FlaviPR2bis, and FlaviPF3S primers specific for NS5, a gene highly conserved among flaviviruses. Phylogenetic inference analysis performed using the maximum likelihood algorithm implemented in PhyML showed that six sequences clustered with DENV (bootstrap value = 53.5%). Although this study supports other reports of DENV detection in bats and arthropods other than Aedes mosquitoes, the role of these ectoparasitic flies and of hematophagous bats in the epidemiology of DENV still warrants further investigation.

Although emerging nonviral pathogens remain relatively understudied in bat populations, there is an increasing focus on identifying bat-associated bartonellae around the world. Many novel strains have been described from both bats and their arthropod ectoparasites, including, a zoonotic agent of human endocarditis. This cross-sectional study was designed to describe novel strains isolated from bats sampled in Mexico and evaluate factors potentially associated with infection. A total of 238 bats belonging to seven genera were captured in five states of Central Mexico and the Yucatan Peninsula. Animals were screened by bacterial culture from whole blood and/or polymerase chain reaction of DNA extracted from heart tissue or blood. spp. were isolated or detected in 54 (22.7%) bats, consisting of 41 (38%) hematophagous, 10 (16.4%) insectivorous, and three (4.3%) phytophagous individuals. This study also identified as another possible bat reservoir of. Univariate and multivariate logistic regression models suggested that infection was positively associated with blood-feeding diet and ectoparasite burden. Phylogenetic analysis identified a number of genetic variants across hematophagous, phytophagous, and insectivorous bats that are unique from described bat-borne species. However, these strains were closely related to those bartonellae previously identified in bat species from Latin America.

Bartonellae are emerging blood-borne bacteria that have been recovered from a wide range of mammalian species and arthropod vectors around the world. Bats are now recognized as a potential wildlife reservoir for a diverse number of Bartonella species, including the zoonotic Candidatus B. mayotimonensis. These bat-borne Bartonella species have also been detected in the obligate ectoparasites of bats, such as blood-feeding flies, which could transmit these bacteria within bat populations. To better understand this potential for transmission, we investigated the relatedness between Bartonella detected or isolated from bat hosts sampled in Mexico and their ectoparasites. Bartonella spp. were identified in bat flies collected on two bat species, with the highest prevalence in Trichobius parasiticus and Strebla wiedemanni collected from common vampire bats (Desmodus rotundus). When comparing Bartonella sequences from a fragment of the citrate synthase gene (gltA), vector-associated strains were diverse and generally close to, but distinct from, those recovered from their bacteremic bat hosts in Mexico. Complete Bartonella sequence concordance was observed in only one bat-vector pair. The diversity of Bartonella strains in bat flies reflects the frequent host switch by bat flies, as they usually do not live permanently on their bat host. It may also suggest a possible endosymbiotic relationship with these vectors for some of the Bartonella species carried by bat flies, whereas others could have a mammalian host.