Monday, October 28, 2024

Why have Hong Kong's zoo monkeys been dying?

An unusual illness

Hi, it's Karoline in Singapore. A dozen monkey deaths in fellow financial hub Hong Kong could be troubling news for animal conservationists and a general public wary of another serious disease outbreak. But there's likely no cause for alarm when it comes to humans. Before I explain...

Today's must-reads

  • McDonald's ruled out beef as the source of its E. coli outbreak.
  • Eli Lilly expects to start selling its popular weight-loss drug in Hong Kong as early as the end of this year.
  • An Indian pharma firm is sending Nvidia AI chips to Russia.

A primate mystery 

Some of Hong Kong's biggest news in recent weeks: A monkey crisis. 

The city's main zoo, the Hong Kong Zoological and Botanical Gardens, reported that 12 animals — including some critically endangered cotton-top tamarins, raising conservationists' concerns — had begun dying in mid-October. Most of them succumbed to sepsis brought on by melioidosis, a dangerous bacterial infection normally found in tropical climates.

Authorities confirmed that 78 other mammals housed in the facility were unaffected, and Hong Kong's government closed a section of the zoo for disinfection and cleaning. In a press conference earlier this month, officials reassured the public that risk of the infection spreading to humans from monkeys is low.

"Melioidosis is generally not transmitted from person to person, nor from animals to people," said Edwin Tsui, controller of Hong Kong's Centre for Health Protection. "The public does not need to worry too much."

Melioidosis is caused by a soil-dwelling bacterium called Burkholderia pseudomallei. It can cause diarrhoea, pneumonia, loss of appetite, and in serious cases even result in a dangerous bloodstream infection, or sepsis. Both humans and animals can contract the disease, typically from direct contact with water or soil contaminated by the bacterium. Authorities said an underground-pipe repair work at a location near the zoo might have caused the bacterium to be exposed as a result of the soil being dug out.

Hong Kong's monkey deaths could mark a setback for conservation efforts. Cotton-top tamarins are small tree-dwellers native to the tropical forests of South America, the Smithsonian's National Zoo and Conservation Biology Institute says. They are one of the most threatened primates on the planet, with only a few thousand remaining, according to the Whitley Fund for Nature.

Still, this isn't Hong Kong's first brush with melioidosis. In fact, the bacterial infection is endemic and has been listed as a legally notifiable infectious disease since 2022 after an outbreak that year affected dozens of people, with nine deaths recorded.

So far this year, 19 people have contracted melioidosis in the city, which is slightly more than last year's number. These cases are "sporadic, with no clustering," according to Tsui. They "do not show a special upward trend."

Extreme weather-related events such as typhoon and floods could also cause a melioidosis outbreak as they increase the chances of the bacteria seeping into water or be exposed as a result of soil disturbance.

In storm-prone Taiwan, 69 cases of melioidosis were reported within a month after Typhoon Gaemi hit the island in July, according to Taiwan's CDC. The island's total number of cases this year is nearly 100, with 18 deaths, a record since 2001. 

We could be on the way to eliminating future deaths from the disease: Researchers gathered at the 10th World Melioidosis Congress in Darwin last week, saying a vaccine may not be far off, the Australian Broadcasting Corp. reported. In the meantime, I and many others will be hoping the rest of Hong Kong's monkeys stay healthy. —Karoline Kan

What we're reading

The New York Times reports on a trans researcher's pursuit of better data on detransition.  

How the US's swing state voters are weighing health care ahead of the country's election, via the Washington Post.

Here are the key takeaways from the LA Times's investigation into the science behind an alternative autism therapy.

Contact Prognosis

Health questions? Have a tip that we should investigate? Contact us at AskPrognosis@bloomberg.net.

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