In the\u00a0study, published in\u00a0PLOS One<\/em>, researchers screened 41 samples of bat guano fertilizers commonly sold in Thai markets for the presence of coronaviruses. While all the samples were from products bought in Thailand, the researchers couldn\u2019t determine the exact origins of the guano contained in each product, which may have been from outside the country.<\/p>\n Two of the samples tested positive for\u00a0Alphacoronaviruses<\/em>, another genus of coronaviruses, and one tested positive for\u00a0Betacoronaviruses.\u00a0<\/em>Genetic analysis showed the\u00a0Betacoronavirus<\/em>\u00a0sample was closely genetically related to the\u00a0sarbecovirus<\/em>\u00a0subgenus, the group that includes the Covid-causing pathogen, SARS-CoV-2.<\/p>\n Importantly, the researchers note the viral strains detected are not known to infect humans. Moreover, they only detected a fragment of viral RNA, the genetic blueprint of viruses, and did not fully isolate a live virus in the samples. As a result, they couldn\u2019t definitively confirm the genetic material detected is capable of posing risks to human health.<\/p>\n Nonetheless, the materials detected indicate that viruses present in bat populations might be able to survive outside of the immediate vicinity of bat roosts and within publicly available agricultural products, the study says.<\/p>\n \u201cThe most surprising thing was that these viruses don\u2019t just stay in the caves,\u201d Thachawech Kimprasit, a medical microbiologist at Mahidol University in Bangkok and senior author of the study, told Mongabay in an interview. \u201cTheir material can be found in commercial end products.\u201d Further research will be required to confirm whether live, intact viruses can survive, he added.<\/p>\n While the genetic material detected poses no risk to human health, the study\u2019s findings highlight an urgent need for enhanced biosecurity measures and safety protocols throughout the fertilizer supply chain to protect guano harvesters, agricultural staff and processing personnel from exposure to pathogens, Thachawech said.<\/p>\n \u201cBiosecurity management of bat guano fertilizers might require heat treatment or chemical treatment to remove the virus raw genetic material,\u201d he said. \u201cWe should also focus on maintaining safe ecological boundaries between bats and people.\u201d<\/p>\n Bats, like many other species of mammal, are natural reservoirs for zoonotic viruses such as\u00a0Betacoronaviruses<\/em>\u00a0and are capable of hosting pathogens without falling ill themselves owing to their specialized immune systems.<\/p>\n Since\u00a0Betacoronaviruses\u00a0<\/em>have been known to infect humans, the researchers used rapid genetic sequencing techniques to investigate the most likely natural host of this guano sample. They identified the croslet horseshoe bat (Rhinolophus coelophyllus<\/em>),\u00a0<\/em>an insectivorous and cave-roosting species widely distributed across mainland Southeast Asia, from Myanmar, Thailand and Laos to Peninsular Malaysia, as the most likely host.<\/p>\n \u201cThe real issue is not the bats themselves, but human disruption of their habitats, which increases the risk of disease transmission,\u201d said Thura Soe Min Htike, a conservation officer at the Nature Conservation Society\u2013Myanmar, who was not involved in the Thailand study.<\/p>\n Previous research\u00a0has found increased exposure to coronaviruses that circulate in bat populations among communities who depend on forest-related livelihoods, such as logging, hunting or harvesting forest products.<\/p>\n Prior studies in Southeast Asia have also\u00a0underscored\u00a0the need for stricter bat guano harvesting safety protocols in rural areas to reduce the risk of\u00a0viral spillover to humans\u00a0and to minimize disturbance of important bat roost sites that are key to species\u2019 survival.<\/p>\n Maintaining healthy populations of bats is vital to wider ecosystem health. Bats control insect populations and pollinate plants, processes that have been shown to enhance yields of important crops, such as\u00a0durian,\u00a0rice\u00a0and\u00a0cocoa, that provide vital income for many rural households.<\/p>\n The new study from Thailand is a clear example of how virology research can help scientists better predict, prevent and manage future zoonotic disease risks, Thura told Mongabay in an email. \u201cPeople have had exposure to bat guano for a long time,\u201d he said, adding that rural communities have used bat guano from extensive cave systems found across Southeast Asia to fertilize their farmland for generations.<\/p>\n The new findings, however, accentuate the need for systematic measures to reduce the risk of contamination and spillover from these practices. Outreach programs in remote areas where household use is common will be key, he says, \u201cHealth education among rural communities is critical.\u201d<\/p>\n According to Thachawech, the best way to minimize the risk of human exposure to viruses present in wild animal populations is to follow the\u00a0widely recognized \u201cOne Health\u201d approach, which recognizes the interconnectedness of human, animal and environmental health. \u201cPeople\u2019s health and environmental health is the same health,\u201d he said. When it comes to bat roosts, this means minimizing disturbance: \u201cThere\u2019s no need to disturb bat roosts.\u201d<\/p>\n While the study clearly indicates the presence of\u00a0Betacoronavirus<\/em>\u00a0genetic material in commercial fertilizer sold in Thailand, the research has limitations, Thachawech noted. The study\u2019s relatively small sample size of 41 limits the team\u2019s ability to draw conclusions about how viral loads circulate in products across the wider region, he said. The unclear origins of the guano contained in each fertilizer sample also makes it impossible to determine the geographic origin of the detected virus.<\/p>\n Little is known about whether the\u00a0Betacoronavirus<\/em>\u00a0identified in the study could possibly infect humans, Thachawech said. This would require it to be able to bind to human cells, replicate in them and transmit between people. As a next step, the team aims to analyze more fertilizer samples to isolate and sequence live\u00a0Betacoronavirus<\/em>\u00a0genomes to better understand the infection risk and full public health implications.<\/p>\n Thachawech and his colleagues also plan to measure viral antibody levels in people living near bat roosts and well-known guano harvesting sites to investigate how much exposure communities have had to zoonotic viruses that may be circulating in local bat populations.<\/p>\n In the meantime, the researchers urge fertilizer companies, regulators and farmer extension groups to introduce better safety and quality standards. Protective clothing, including masks and gloves, should be essential; industrial processing should take place under biosecure conditions; and screening of all wildlife-derived products for the presence of zoonotic viruses should be an ongoing practice, they say.<\/p>\n As the authors say in their study: \u201cAlthough the precise origin of the detected virus remains undetermined, proactive strategies should be prioritized to mitigate future zoonotic threats and safeguard public health.\u201d<\/p>\n Eby, P., Peel, A. J., Hoegh, A., Madden, W., Giles, J. R., Hudson, P. J., & Plowright, R. K. (2022). Pathogen spillover driven by rapid changes in bat ecology.\u00a0Nature<\/em>,\u00a0613<\/em>(7943), 340-344. doi:10.1038\/s41586-022-05506-2<\/a><\/p>\n Suwannasing, R., & Kimprasit, T. (2026). Bat guano fertilizer as a source of\u00a0Betacoronavirus<\/em>: First molecular evidence linking\u00a0Rhinolophus coelophyllus<\/em>\u00a0to viral reservoirs in Thailand.\u00a0PLOS One<\/em>,\u00a021<\/em>(3), e0344265. doi:10.1371\/journal.pone.0344265<\/a><\/p>\n Evans, T. S., Tan, C. W., Aung, O., Phyu, S., Lin, H., Coffey, L. L., \u2026 Thu, H. M. (2023). Exposure to diverse\u00a0sarbecoviruses<\/em>\u00a0indicates frequent zoonotic spillover in human communities interacting with wildlife.\u00a0International Journal of Infectious Diseases<\/em>,\u00a0131<\/em>, 57-64. doi:10.1016\/j.ijid.2023.02.015<\/a><\/p>\n Aung, M. M., Htike, T. S., Phwe, N. P., Aung, O., Aung, P. P., Yae, W. M., \u2026 Evans, T. S. (2026). Limestone Karst ecology and anthropogenic activities associated with cave-dwelling bats of southern Shan state, Myanmar.\u00a0Global Ecology and Conservation<\/em>,\u00a067<\/em>, e04071. doi:10.1016\/j.gecco.2026.e04071<\/a><\/p>\n Ruiz-Aravena, M., McKee, C., Gamble, A., Lunn, T., Morris, A., Snedden, C. E., \u2026 & Plowright, R. K. (2022). Ecology, evolution and spillover of coronaviruses from bats.\u00a0Nature Reviews Microbiology<\/em>,\u00a020<\/em>(5), 299-314. doi:10.1038\/s41579-021-00652-2<\/a><\/p>\n Bumrungsri, S., Sripaoraya, E., Chongsiri, T., Sridith, K., & Racey, P. A. (2009). The pollination ecology of durian (Durio zibethinus<\/em>, bombacaceae) in southern Thailand.\u00a0Journal of Tropical Ecology<\/em>,\u00a025<\/em>(1), 85-92. doi:10.1017\/s0266467408005531<\/a><\/p>\n Wanger, T. C., Darras, K., Bumrungsri, S., Tscharntke, T., & Klein, A. (2014). Bat pest control contributes to food security in Thailand.\u00a0Biological Conservation<\/em>,\u00a0171<\/em>, 220-223. doi:10.1016\/j.biocon.2014.01.030<\/a><\/p>\n Maas, B., Clough, Y., & Tscharntke, T. (2013). Bats and birds increase crop yield in tropical agroforestry landscapes.\u00a0Ecology letters<\/em>,\u00a016<\/em>(12), 1480-1487. doi:10.1111\/ele.12194<\/a><\/p>\nMinimize human disturbance of bat roosts<\/strong><\/h3>\n
Origins and infection risk require deeper investigation<\/strong><\/h3>\n
Citations:<\/strong><\/h2>\n
![\"Cave](\"https:\/\/imgs.mongabay.com\/wp-content\/uploads\/sites\/20\/2026\/07\/25102319\/Cave-entrance-in-Thailand.-Image-by-Jayakarthi-Natarajan-via-Wikimedia-Commons-CC-BY-SA-4.0-scaled.jpg "\\"\\"")
![\"Virology](\"https:\/\/imgs.mongabay.com\/wp-content\/uploads\/sites\/20\/2026\/07\/25102613\/Thachawech-Kimprasit-laboratory.jpg "\\"\\"")
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