Japanese macaque monkeys huddle together in a group to protect themselves against the cold weather at Awajishima Monkey Center on January 18, 2014 in Sumoto, Hyogo Prefecture, Japan. (Buddhika Weerasinghe/Getty Images)

Wild Japanese monkeys near the Fukushima Daiichi nuclear power plant have lower white and red blood cell counts than similar monkeys from almost 200 miles away, according to biologists.

In a paper published last week, scientists said they had tested Japanese macaques captured and killed in a forest about 40 miles from the power plant and compared the results with macaques in Shimokita Peninsula, a remote area in the country’s north.

The monkeys in the vicinity of Fukushima City had detectable levels of radioactive cesium in their muscles, while the northern monkeys did not. Researchers also found that the Fukushima simians had significantly lower white and red blood cell counts.

The Fukushima nuclear plant released a large amount of radioactive material into the environment following a massive earthquake and tsunami on March 11, 2011.

“These results suggest that the exposure to some form of radioactive material contributed to hematological changes in Fukushima monkeys,” according to the study’s lead author, Kazuhiko Ochiai, a researcher at Nippon Veterinary and Life Science University in Tokyo, and colleagues.

The authors said the consequences of their findings remained unclear but they “may suggest that the immune system has been compromised to some extent, potentially making individual animals and the entire troop susceptible to, for example, epidemic infectious disease.”

The researchers suggested their findings mirrored studies conducted on humans after the 1986 Chernobyl disaster in Ukraine, where researchers found decreased blood cell counts in people living in contaminated areas.