A twelfth monkey has died at a Hong Kong zoo, with tests underway to determine if it succumbed to the same bacterial infection that killed 11 other monkeys in the past 10 days.

The De Brazza’s monkey had been isolated since 13 October when the first eight deaths were reported.

Autopsies have found a large amount of sepsis-inducing bacteria that likely came from contaminated soil near the primates’ enclosures, authorities said.

Workers who were digging up soil near the primates’ cages were believed to have brought in contaminated soil through their shoes, Hong Kong’s Culture, Sports and Tourism Secretary told local broadcaster RTHK.

The 11 monkeys found dead earlier include the critically endangered cotton-top tamarins, as well as white-faced sakis, common squirrel monkeys, and a De Brazza’s monkey.

Authorities said they died due to melioidosis, an infectious disease that can spread through contact with contaminated soil, air, or water.

It is caused by Burkholderia pseudomallei, a soil-dwelling bacterium strain endemic in tropical and subtropical regions.

“Similar lesions were also found in the tissues of the organs of the monkey that died today,” the Leisure & Cultural Services Department said.

The health conditions of the 78 mammals still in the zoo are “normal”, it added.

The Hong Kong Zoological and Botanical Gardens, the city’s oldest park covering 14 acres in the city centre, has closed its mammals section since 14 October for disinfection and cleaning.

Jason Baker, the senior vice president animal rights group Peta, told Reuters last week that the deaths raise concerns about the risk of zoonotic diseases like monkeypox, which can spread from animals to humans.

“Monkeys in captivity are often exposed to pathogens that can be transmitted to humans, including tuberculosis, Chagas disease, cholera and MRSA,” Baker said.

The earliest report of melioidosis in Hong Kong dates back to 1975 and 1976, when 24 dolphins suddenly died of the disease in Ocean Park, an animal theme park.

BBC