updated 1/25/2010 1:36:32 PM ET 2010-01-25T18:36:32

A common parasite associated with diarrhea and irritable bowel syndrome appears to be spreading among animals, and from animals to zookeepers, at several zoos worldwide, according to a new study.

The resulting infection, called Blastocystis, has been identified in humans, non-human primates, elephants, giraffes, quokkas (a small, Australian mammal), southern hairy nosed wombats and western gray kangaroos at zoos in Australia, Belgium, Japan, Malaysia, The Netherlands and Spain, and scientists believe the bug is prevalent "in most zoos."

While this parasitic illness is not usually serious, its presence at so many zoological parks, and among so many different species, demonstrates the need for zoos to closely monitor the health of their staff and animal charges.

"Zoos are indeed a hot spot for interspecies spread of infectious diseases," co-author Bruno Levecke told Discovery News.

Levecke, a parasitologist at Ghent University and the Royal Zoological Society of Antwerp, and his colleagues collected fecal samples from zookeepers and various animals at The Perth Zoological Gardens in Western Australia, the Melbourne Zoo, the Werribee Open Range Zoo in Victoria, Australia, and unidentified zoos from Amsterdam and Antwerp.

The study, accepted for publication in the journal Veterinary Parasitology, concluded that the parasite was present in most of the test subjects. Sixty-three percent of zookeepers tested positive and up to 82 percent of certain animal populations were infected with Blastocystis.

Prior studies at Osaka Zoo in Japan, Malaysia's Zoo Negara, Spain's Pena Escrita, and zoos in the United Kingdom and Denmark also reported infections with the parasite, some of which were found in birds.

Zoo babies

While it is difficult to determine exactly how the parasite is spreading, project leader Unaiza Parkar told Discovery News, "Blastocystis can be transmitted directly — contact with infected stool — or indirectly — consumption of contaminated food and/or water. Given the housing conditions for the non-human primates, usually four to six primates sharing an enclosure, there is definitely transmission occurring between the animals."

"It is most likely that it is being transmitted from animals to the keepers while performing daily duties, such as cleaning the animal enclosures," added Parkar, a researcher in the School of Veterinary and Biomedical Sciences at Murdoch University.

She and her colleagues, for example, think that when zookeepers spray down animal enclosures with water, they may come in contact with the parasite.

Levecke did not rule out, however, that humans were spreading the parasite to the zoo animals.

"Animals can get infected by contaminated food prepared by animal caretakers," he explained.

Blastocystis is just one of several gastrointestinal parasites and other bugs that scientists are monitoring. Levecke recently led another study that found Giardia duodenalis in non-human primates at a sanctuary and several zoos in Belgium and The Netherlands. Giardia can lead to severe diarrhea and chronic illness, if left untreated.

"Zoos may review the occupational health and safety guidelines for zookeepers based on the findings of our study," Parkar said.

"This may include the emphasis on the importance of hygiene through frequent hand washing and the use of gloves while handling animals," she added. "Zoos should encourage staff to undergo routine — every one to two years — diagnostic tests for their own well-being."

© 2012 Discovery Channel

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