A typical roundworm measures roughly 2.7% of the typical size of a Bengal tiger or weighs simply three-millionths of 1 p.c of the biggest of the world’s large cats.
Although these parasites don’t pose a significant risk to Bengal tigers (Panthera tigris), researchers throughout South Asia, the cat’s native vary, warn that parasitic infections can act as silent killers, notably when the large cats are weakened by poor diet, damage or different ailments.
South Asia is dwelling to roughly 4,367 Bengal tigers: 3,682 in India, 429 in Nepal, 131 in Bhutan and 125 in Bangladesh, in keeping with the most recent estimates.
The IUCN lists the Bengal tiger as an endangered species, though it’s labeled as critically endangered in Bangladesh.
Bangladeshi researchers, analyzing fecal samples collected from wildlife throughout the Sundarbans mangrove forest, detected the best parasite an infection price in Bengal tigers. A examine revealed by the Bangladesh Forest Division in July makes suggestions to handle the problem.
Sultan Ahmed, a professor within the Division of Microbiology and Immunology at Sylhet Agricultural College and one of many authors of the examine, instructed Mongabay, “Crucial suggestion is to maintain the mangrove forest away from human interference.”
Assigned by the Forest Division, the researchers collected fecal samples in two phases in 2024 and 2025.
In line with their evaluation, the best parasite an infection price, 85.3%, was detected in Bengal tigers, adopted by 84.9% in rhesus monkeys (Macaca mulatta), 73.6% in deer and 66.7% in wild pigs.
In molecular evaluation, roundworms (together with Toxocara cati and Strongyloides spp.), hypdatid worms (Echinococcus granulosus), liver flukes (Opisthorchis clonorchis) and parasitic tapeworms (Spirometra spp.) have been detected because the predominant parasite species within the wild animals studied.
The function of human settlements
The examine throughout the Bangladesh a part of the Sundarbans discovered households have been, on common, about 450.7 meters (1,479 toes) from the forest, however the median distance was simply 100 m (328 ft), indicating that many properties have been situated near the forest edge.
It stated that the proximity and shared environments between home animals and wildlife facilitate the transmission of pathogens throughout species.
Printed in 2025, a separate examine on Bengal tigers and leopards on the Wildlife Analysis and Coaching Centre in Gorewada within the Indian state of Maharashtra, detected a number of parasitic infections, together with Sarcocystis spp., Toxocara cati, Spirometra spp. and one other type of tapeworm, Diphyllobothrium spp.
This examine’s researchers warned that such infections could cause persistent malnutrition, particularly beneath irritating circumstances and have an effect on Bengal tigers’ health and reproductive success, and, in extreme circumstances, result in loss of life.
Citing research in Maharashtra in western India, the researchers steered that habitat encroachment and the ensuing human-wildlife interactions elevated the danger of parasite transmission between wild and home animals, as free-ranging wildlife was discovered to be uncovered to various pathogens in shared environments.
Parag Nigam, Head of the Division of Wildlife Well being Administration beneath the Wildlife Institute of India, observes that home cattle, buffalo and free-roaming canines function main reservoirs for helminths, flukes, and tick-borne pathogens, which spill over into shared pastures and water sources.
Stressing the significance of breaking transmission chains at human-wildlife boundaries and sustaining excessive pure immunity throughout wild populations, he instructed Mongabay, “The best baseline measure is managing the livestock buffer surrounding tiger reserves.”
One other 2025 examine on gastrointestinal parasites in wild mammals in Chitwan Nationwide Park, Nepal, discovered that the proximity of wildlife habitats to human settlements in Chitwan intensifies the danger of zoonotic transmissions, notably from parasites akin to Sturdy-yloides spp. and Toxocara spp.
One of many authors of the examine, Babita Maharjan, an assistant professor at Tribhuvan College’s Amrit Campus and a member of the Nepal Zoological Society, instructed Mongabay. “Wildlife-livestock interplay could improve the danger of transmission of infections to tigers immediately by means of consumption of contaminated livestock and not directly by means of shared habitats, water sources, and contaminated prey populations.”
In 2018, a Bengal tiger in Bhutan was recognized with deadly neurocysticercosis, an an infection of the central nervous system, attributable to Taenia solium, generally often called pork tapeworm, marking the primary recorded case of this human parasite in a non-domestic cat.
Analyzing the loss of life, a 2021 examine stated that the mechanism for the parasite publicity on this uncommon case was unknown.
Nevertheless, the examine says: “It’s potential that the tiger could have ingested infective T. solium eggs by means of direct consumption of human fecal or consumption of water or meals contaminated with human feces.”
Digicam-trap information from Bhutan’s Nature Conservation Division confirmed that the deceased tiger’s dwelling vary prolonged to the outskirts of massively populated Thimphu, in keeping with the examine.
Why parasite an infection is regarding
Wildlife well being skilled Parag stated parasites are an actual challenge for Bengal tigers, however poaching, forest degradation and absence of prey are nonetheless the primary enemies of the animal.
“That stated, you possibly can’t simply ignore these parasites both,” he stated. “They act like a sluggish, quiet drain on a tiger’s well being.”
A robust, totally grown, wild tiger can normally deal with a primary parasite load with out a lot bother but when it will get previous, injured or can’t discover sufficient meals, these intestinal worms and tick-borne blood parasites take a heavy toll, Parag defined.
The parasites weaken the animal additional, trigger extreme anemia and wreck its capacity to hunt wild prey. A weak tiger then turns to village cattle as a result of they’re simpler to catch, which immediately triggers human-tiger battle within the fringe areas.
“The larger fear is what occurs to the cubs, and smaller, remoted reserves,” Parag stated. “Roundworms and flukes can simply kill younger cubs earlier than their immune methods even construct up, which hits the native tiger inhabitants development onerous.
“Plus, in smaller pockets the place tigers don’t have sufficient genetic selection, their immunity takes a success, making entire teams weak to sudden illness.”
Zoologist Babita warned that parasitic infections could be a critical well being and conservation concern for Bengal tigers, notably when an animal is immunocompromised, injured, nutritionally burdened or uncovered to heavy or a number of infections.
“A number of infections are sometimes extra damaging than single infections, can weaken the immune system, and make an animal extra vulnerable to further ailments,” she stated.
Prevention measures
Sultan, one of many authors of the most recent examine, steered an built-in, long-term wildlife illness surveillance program within the Sundarbans to observe parasitic and different infectious ailments in Bengal tigers and their prey species.
He additionally suggested parasite management in livestock and home animals across the mangrove forests and periodic de-worming of forest division workers.
“A Central Wildlife Illness Diagnostic Laboratory needs to be established,” Sultan stated.
Parag stated that minimizing parasitic dangers in wild tigers requires landscape-level, ecosystem-based methods slightly than direct veterinary interventions.
He advisable that authorities implement routine, non-invasive monitoring by analyzing fecal samples collected throughout annual, on-site surveys.
Prey inhabitants administration performs a significant, oblique function in mitigating parasitic threats, Parag added: “When wild prey is considerable and straightforward to hunt, tigers stay in peak bodily situation, permitting their immune methods to naturally suppress and tolerate endemic parasite masses.”
To reap the benefits of prey administration, he steered prioritizing lively grassland administration and water-body upkeep to maintain optimum densities of untamed ungulates and rigorously surveilling them for illness to forestall outbreaks. Sustaining clear flows of water to restrict the focus of aquatic snails and vector larvae can be required, he stated.
Educating forest-dependent communities about correct grazing practices, hygiene and de-worming of livestock can even improve the effectiveness of those measures to mitigate gastrointestinal parasite infections in tigers, Babita stated.
She additionally advisable interdisciplinary collaboration with epidemiologists, ecologists, biologists and medical and veterinary professionals.
Citations:
Kolangath, S. M., Upadhye, S. V., Pawshe, M. D., Shalini, A. S., Dhoot, V. M., & Bhangale, P. Okay. (2025). Parasitic profiling of tigers and leopards of Maharashtra. Worldwide Journal of Veterinary Sciences and Animal Husbandry, 10(3), 42–46. doi:10.22271/veterinary.2025.v10.i3a.2107
Maharjan, B., Jain, P., & Koju, N. P. (2025). Zoonotic dangers and conservation challenges: Gastrointestinal parasites in wild mammals of Chitwan Nationwide Park, Nepal. Worldwide Journal for Parasitology: Parasites and Wildlife, 26, 101041. doi:10.1016/j.ijppaw.2025.101041
Phuentshok, Y., Choden, Okay., Alvarez Rojas, C. A., Deplazes, P., Wangdi, S., Gyeltshen, … Gurung, R. B. (2021). Cerebral cysticercosis in a wild Bengal tiger (Panthera tigris tigris) in Bhutan: A primary report in non-domestic felids. Worldwide Journal for Parasitology: Parasites and Wildlife, 14, 150–156. doi:10.1016/j.ijppaw.2021.02.003
This article by Sadiqur Rahman was first revealed by Mongabay on 4 September 2026. Lead Picture: South Asia is dwelling to roughly 4,367 Bengal tigers. Researchers say parasitic infections may act as silent killers to the cats by way of Wikimedia Commons (CC BY-SA 4.0).
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