Dozens of tigers die of canine distemper at Thai tourist parks

An outbreak of canine distemper virus (CDV) killed 72 tigers at 2 tourist animal parks in northern Thailand last month, officials said, ruling out earlier concerns that the deaths were linked to avian influenza.¹

All of the tigers died within a span of less than 2 weeks.

“By the time we realised they were sick, it was already too late,” Somchuan Ratanamungklanon, director of Thailand’s national livestock department, told local media, stating that illness can be more difficult to detect in tigers than in domestic animals such as dogs and cats.²

The tigers were housed at facilities operated by Tiger Kingdom in Chiang Mai province, where they became ill and died over roughly a 10-day period between February 8 and 18, according to Thai authorities. Autopsies conducted by regional livestock officials detected genetic material from CDV in samples collected from the animals.¹ Officials also found traces of bacteria associated with respiratory disease, though the Chiang Mai regional livestock office said no evidence of influenza A virus (bird flu) was found.¹

The deaths occurred at 2 Tiger Kingdom facilities located about 18 miles apart in the Mae Taeng and Mae Rim districts. The parks, popular tourist attractions where visitors can interact with captive tigers, have since closed while officials disinfect the facilities.

In a news conference late February, officials said the outbreak appeared to have subsided, and no additional tiger deaths have been reported since the initial cluster.² Severely ill tigers were recommended to be euthanized.²

Public health authorities emphasized that CDV is not known to infect humans but said they are monitoring staff and others who had recent contact with the animals. No human illness has been reported.

Bird flu initially suspected

Thai officials addressed the outbreak at a news conference in Bangkok late last month after speculation circulated that the tiger deaths could be linked to bird flu. They reassured the public that the tigers did not die of bird flu.

Thailand experienced a bird flu outbreak between 2004 and 2007, during which 17 people died out of 25 confirmed human cases associated with infected poultry.¹ This time, laboratory testing instead pointed to CDV as the likely cause.

CDV in species outside of dogs

CDV is widely recognized in veterinary medicine as a highly contagious viral disease primarily affecting domestic dogs, though it can infect a broad range of carnivores.³

The virus spreads through airborne respiratory droplets or contact with infected animals and contaminated objects. Sneezing, coughing, barking, shared food and water bowls, and contact with infected bodily fluids are all potential routes of transmission.³

In addition to dogs, ferrets, raccoons, skunks, and other wildlife species are susceptible to CDV. Domestic cats can become infected but rarely develop clinical illness, according to the American Veterinary Medical Association.³ Although these felines are typically resistant to illness from CDV, their larger, wild counterparts, such as tigers and lions, are more susceptible to the disease.

The confined environment of the tigers at the Thai parks could have made them more vulnerable to CDV infection.

Thai officials noted that infection can produce stronger clinical signs in tigers living in confined environments, where stress and inbreeding conditions may make them more susceptible to viral infection.¹

Clinical signs of CDV vary widely depending on the strain of the virus, the age of the host, and the presence of secondary infections.⁴ Early signs often include ocular and nasal discharge, depression, and loss of appetite. As the disease progresses, animals may develop fever, coughing, respiratory distress, vomiting, diarrhea, and systemic illness.⁴ Neurologic symptoms, including seizures, circling, loss of coordination, or paralysis, can also occur in affected animals. Some infected animals may remain subclinical but still shed virus for extended periods.

The virus infects epithelial, mesenchymal, hematopoietic, and neuroendocrine cells, leading to disease throughout the entire body, affecting the respiratory, gastrointestinal, and central nervous systems.

Source of infection still unknown

Authorities have not confirmed the origin of the outbreak.

Visit Arsaithamkul, a veterinarian who participated in the necropsies, suggested in a Facebook post that the close proximity of the 2 facilities could indicate a shared source of exposure, saying he suspected the source could have been food that the tigers at both parks were fed.¹ According to Ratanamungklanon, officials collected samples from the tigers, the chicken they eat, and their surrounding environment.²

More than 240 tigers were reportedly housed across the 2 Tiger Kingdom facilities before the outbreak.

Animal welfare organizations have criticized the facilities’ use of captive tigers for human entertainment, saying such environments can increase the risk of infectious disease outbreaks.

Thai livestock authorities said the virus is no longer spreading within the facilities. According to previous news reports, Tiger Kingdom Chiang Mai said it was temporarily closing for 2 weeks as of February 24.²

An emerging viral threat to tiger conservation

Beyond the immediate outbreak, veterinarians and conservation researchers have raised concerns about the implications of CDV for tiger populations. The International Union for the Conservation of Nature classifies these felines as endangered. Currently, an estimated 3726 to 5578 wild tigers remain in the wild across 10 countries, making the species the most endangered big cat in the world.⁵

CDV has a near-global distribution and can cause high mortality in domestic dogs and many species of wild carnivores. Fatal infections in wild Amur tigers have been documented in the Russian Far East since 2003, raising concerns that the virus could represent a growing threat to tiger conservation, according to reports from Cornell University’s K. Lisa Yang Center for Wildlife Health.⁵

Researchers note that tigers typically become infected through spillover from other species that serve as reservoirs for the virus, including domestic dogs or more abundant wild carnivores.⁵ According to the Center for Wildlife Health, CDV infections in tigers are short-lived, with the animal either dying or recovering and developing lifelong immunity. Due to this, the virus instead usually enters the tiger population through other species.

Tigers infected with CDV initially experience respiratory and gastrointestinal disease, with the disease potentially progressing to involve the central nervous system. Neurologic infection may lead to unusual behaviors such as loss of fear or reduced aggressive responses, which can negatively impact these animals in the wild.⁵

At Cornell University, researchers have conducted population viability analyses of tigers, estimating that a population of 25 of these felines could be 65% more likely to head toward extinction within 50 years in the presence of CDV.⁵

With populations already small and increasingly isolated, these big cats may be less able to withstand outbreaks of infectious diseases like CDV.

References

1. Audjarint W. Thai officials say 72 tigers at tourist parks died of canine distemper, allaying bird flu fears. AP News. February 24, 2026. Accessed March 5, 2026. https://apnews.com/article/thailand-tigers-canine-distemper-bird-flu-fears-0012db4e8a20775e424693f7e238a92a
2. EWE K. Probe under way after illness kills 72 tigers in Thai tourist park. BBC. February 24, 2026. Accessed March 5, 2026. https://www.bbc.com/news/articles/cly833zjp4po
3. American Veterinary Medical Association. Canine distemper. Accessed March 5, 2026. https://www.avma.org/resources-tools/pet-owners/petcare/canine-distemper
4. Young A, Karsten C. Canine distemper. UC Davis School of Veterinary Medicine. July 9, 2021. Accessed March 5, 2026. https://healthtopics.vetmed.ucdavis.edu/health-topics/canine-distemper
5. Cornell Wildlife Health Center. Canine distemper virus and tigers. Cornell University College of Veterinary Medicine. Accessed March 5, 2026. https://wildlife.cornell.edu/our-work/wild-carnivores/canine-distemper-virus-and-tigers