HONG KONG – A common squirrel monkey was found dead on Sunday at the Hong Kong Zoological and Botanical Gardens, bringing to 11 the number of monkeys that have died at the zoo amid an outbreak of melioidosis, a bacterial infection.

The animal was one of two common squirrel monkeys that had been put under isolation since Oct 16 after they exhibited unusual behavior. The other common squirrel monkey died on Saturday.   

The Agriculture, Fisheries and Conservation Department said it will conduct necropsy to determine if the latest death was also linked to melioidosis.

One more animal — a De Brazza’s monkey — has been under isolation and was being given medication since Oct 13 after the monkey also exhibited unusual behavior, authorities said.

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Part of the zoo, built in 1860 and the oldest park in Hong Kong, has remained shut since Oct 14 when authorities reported the first batch of monkey deaths.

Housed in five separate cages, the deceased monkeys included the De Brazza species as well as cotton-top tamarins and white-faced sakis.

Authorities said nine monkeys died of sepsis after catching melioidosis. Autopsies found a large amount of the melioidosis-inducing bacteria in the monkeys’ organs, which likely came from soil near the monkeys’ habitat, they said.

One of the deceased monkeys was found to have a high level of the bacterium and have had close contact with the other monkeys that also got infected.

READ MORE: HK zoo partially closed after 8 monkeys found dead

Kevin Yeung Yun-hung, the city's secretary for culture, sports, and tourism, said that renovation work at the zoo required digging up the soil near where the monkeys lived.

Workers were then believed to have brought contaminated soil into the cage through their shoes, he said.

The bacteria is particularly common in moist clay soil. Even though it can affect both humans and animals, it is unlikely to be passed from animals to humans, authorities said.

The zoo, located just above the city's financial center and near government house, houses around 158 birds, 70 mammals and 21 reptiles in about 40 enclosures.

With Reuters inputs