@article {156894, title = {Host-Pathogen-Vector Continuum in a Changing Landscape: Potential Transmission Pathways for in a Small Mammal Community.}, journal = {Ecol Evol}, volume = {15}, year = {2025}, month = {2025 Apr}, pages = {e71085}, abstract = {

Bacterial infections account for a large proportion of zoonoses. Our current understanding of zoonotic spillover, however, is largely based on studies from viral systems. Small mammals such as rodents and their ectoparasites present a unique system for studying several bacterial pathogens and mapping their spillover pathways. Using spp. (a Gram-negative bacteria) as a model system within a rainforest human-use landscape, we investigated (1) ecological correlates of prevalence in small mammal hosts and (2) evolutionary relationships between spp. and various hosts and ectoparasites to gain insight into pathogen movement pathways within ecological communities. We detected in five out of eight small mammal species and in 86 (40.56\%) out of 212 individuals, but prevalence varied widely among species (0\%-75.8\%). Seven of the ten ectoparasite species found on these small mammals were positive for . Interestingly, while genotypes (15) in small mammals were host-specific, ectoparasites had nonspecific associations, suggesting the possibility for vector-mediated cross-species transmission. We also found that prevalence in hosts was positively correlated with their aggregated ectoparasite loads, further emphasizing the crucial role that ectoparasites may play in these transmission pathways. Our cophylogenetic analysis and ancestral trait (host) reconstruction revealed incongruence between small mammal and phylogenies, indicating historic host shifts and validating the potential for contemporary spillover events. We found that small mammal hosts in this fragmented landscape often move across habitat boundaries, creating a transmission pathway (via shared ectoparasites) to novel hosts, which may include synanthropic species like . Our results highlight the necessity to disentangle the complex relationship among hosts, ectoparasites, and bacterial pathogens to understand the implications of undetected spillover events.

}, keywords = {bacterial zoonosis; coevolution; ectoparasites; host shifts; vector-borne pathogens.}, issn = {2045-7758}, doi = {10.1002/ece3.71085}, url = {https://pubmed.ncbi.nlm.nih.gov/40177689/}, author = {Ansil, B R and Viswanathan, Ashwin and Ramachandran, Vivek and Yeshwanth, H M and Sanyal, Avirup and Ramakrishnan, Uma} } @article {154152, title = {Identification of Distinct Rodent-Associated Adenovirus Lineages from Mixed-Use Landscape.}, journal = {Ecohealth}, year = {2025}, month = {2025 Feb 04}, abstract = {

Land-use change and increased human-livestock-wildlife interactions have generated numerous possibilities for viral spillover, demanding enhanced surveillance in biodiverse regions. We investigated adenovirus diversity in small mammals, an understudied host taxon, from a forest-plantation mosaic in the Western Ghats biodiversity hotspot. We observed high prevalence (up to 39.39\%) and identified five lineages of adenoviruses with unique mutations in the dominant small mammal species,\ Rattus satarae. These lineages significantly differed from other known murine adenoviruses (p-distance \> 25\%), indicating the likelihood of novel adenoviruses in this endemic small mammal and suggesting potential for unexplored DNA virus diversity in the region.

}, keywords = {DNA viruses; India; small mammals; surveillance.}, issn = {1612-9210}, doi = {10.1007/s10393-025-01700-6}, url = {https://pubmed.ncbi.nlm.nih.gov/39903359/}, author = {Ansil, B R and Sanyal, Avirup and Sreenivas, Darshan and Garg, Kritika M and Ramakrishnan, Uma and Chattopadhyay, Balaji} } @article {116715, title = {Using Environmental Sampling to Enable Zoonotic Pandemic Preparedness.}, journal = {J Indian Inst Sci}, year = {2022}, month = {2022 Sep 07}, pages = {1-20}, abstract = {

The current pandemic caused by the SARS CoV-2, tracing back its origin possibly to a coronavirus associated with bats, has ignited renewed interest in understanding zoonotic spillovers across the globe. While research is more directed towards solving the problem at hand by finding therapeutic strategies and novel vaccine techniques, it is important to address the environmental drivers of pathogen spillover and the complex biotic and abiotic drivers of zoonoses. The availability of cutting-edge genomic technologies has contributed enormously to preempt viral emergence from wildlife. However, there is still a dearth of studies from species-rich South Asian countries, especially from India. In this review, we outline the importance of studying disease dynamics through environmental sampling from wildlife in India and how ecological parameters of both the virus and the host community may play a role in mediating cross-species spillovers. Non-invasive sampling using feces, urine, shed hair, saliva, shed skin, and feathers has been instrumental in providing genetic information for both the host and their associated pathogens. Here, we discuss the advances made in environmental sampling protocols and strategies to generate genetic data from such samples towards the surveillance and characterization of potentially zoonotic pathogens. We primarily focus on bat-borne or small mammal-borne zoonoses and propose a conceptual framework for non-invasive strategies to tackle the threat of emerging zoonotic infections.

}, issn = {0970-4140}, doi = {10.1007/s41745-022-00322-z}, author = {Sanyal, Avirup and Agarwal, Sanskriti and Ramakrishnan, Uma and Garg, Kritika M and Chattopadhyay, Balaji} }