Bats (Chiroptera) are highly diverse mammals that play key ecological roles and harbor a wide range of microorganisms, yet the microbiome of their ectoparasitic flies remains poorly understood. This study characterized and compared the bacterial microbiomes associated with two bat–ectoparasite systems, Pteronotus gymnonotus–Trichobius johnsonae and Desmodus rotundus–Trichobius parasiticus, from cave-dwelling bat populations in northeastern Brazil using 16S rRNA gene sequencing. Sixty-eight bat fly samples were successfully sequenced, and 67 were retained for downstream ecological analyses after quality filtering. Bacterial communities were dominated by members of the classes Gammaproteobacteria and Alphaproteobacteria, with Arsenophonus, Bartonella, and unresolved endosymbiont-associated taxa among the most abundant bacterial groups. Alpha-diversity patterns varied according to the metric considered: observed ASV richness was influenced by bat fly species, sex, and their interaction, Shannon diversity differed according to streblid fly species and sex, and Faith’s phylogenetic diversity differed between bat fly sexes. Notably, male T. johnsonae exhibited greater observed ASV richness than females, whereas no significant sex difference was detected in T. parasiticus. Beta-diversity analyses consistently revealed differences in bacterial community composition between the two bat–ectoparasite systems, while the influence of sex was system-dependent, with significant differentiation between T. johnsonae males and females but not between sexes of T. parasiticus in phylogenetically informed analyses. Differential abundance analysis further identified Romboutsia, Bartonella, Bacteroides, and an unclassified Pseudomonadota genus as discriminatory taxa among groups. Overall, these findings reveal distinct bacterial diversity and composition patterns between the two bat–ectoparasite systems and indicate that sex-associated microbiome variation is not uniform across bat fly species.
Adenoviruses are widespread DNA viruses that infect a broad range of vertebrate hosts and are recognized for their long-term host coevolution, remarkable genetic diversity, and broad pathogenic potential. Coronaviruses circulate among wild birds due to their evolutionary potential and are relevant to animal and public health. However, the diversity and ecological role of these viruses in pelagic seabirds remain poorly understood. This study provides the first molecular survey of adenoviruses and coronaviruses in Procellariiformes from the South Atlantic. Fifty stranded individuals representing 12 Procellariiformes species were collected along the southeastern Brazilian coast, between 2017 and 2023. Adenovirus and coronavirus survey were performed using nested PCR protocols, followed by sequencing, phylogenetic analysis, and histopathology of positive cases. Adenovirus was detected in seven individuals (14%; 95% CI: 5.8–26.7%) from three species: Southern Giant Petrels (Macronectes giganteus), Cory’s Shearwaters (Calonectris borealis), and Black-browed Albatrosses (Thalassarche melanophris). Five sequence types were identified, including similar variants in Southern Giant Petrels and distinct adenoviruses in Cory’s Shearwaters and Black-browed Albatrosses. All viruses clustered within a divergent lineage with adenoviruses previously detected in New Zealand seabirds and a Chimney Swift from the USA. No intranuclear inclusion bodies were found in histopathological analysis. All specimens were coronavirus-negative. This first molecular detection of adenoviruses in Procellariiformes expands the known diversity and host range of seabird adenoviruses and suggests circulation of genetically distinct viruses across oceanic regions, highlighting the need for genomic and epidemiological studies of their evolution, transmission, and health impacts.
Coxiella burnetii, the causative agent of Q fever, is an important zoonotic pathogen affecting livestock and humans worldwide. In Pakistan, epidemiological evidence remains limited, particularly at the human–livestock interface. This study aimed to determine the seroprevalence of C. burnetii and identify associated risk factors among livestock and livestock-exposed humans in Southern Punjab, Pakistan. A cross-sectional study was conducted across six districts, including 4758 livestock comprising goats, sheep, cattle, buffaloes, and camels, and 1019 humans with livestock-associated exposure. Serum samples were tested for the presence of antibodies against C. burnetii using an ELISA assay. Overall 17.65% and 21.98% seroprevalence rates were observed among livestock and humans, respectively at individual-level while 67.3% and 32.3% seroprevalence rates were observed at the herd- and household-level, respectively. Tick infestation, larger herd size, extensive husbandry, transhumant production, and reproductive problems were associated with higher odds of seropositivity. Among humans, livestock ownership, raw milk consumption, placenta handling, family history of abortion, and uncertainty regarding tick exposure were associated with seropositivity. These findings provide evidence of substantial prior exposure to C. burnetii among livestock and humans and highlight Q fever as an underrecognized zoonotic health concern. Integrated One Health surveillance combining serology with molecular and environmental testing, together with improved farm biosecurity and targeted public awareness, is warrant to reduce occupational exposure and ultimately strengthen disease prevention strategies.
