Cases of vomiting, diarrhea among swimmers in southwest Japan river jump to 109

The number of people complaining of vomiting, diarrhea and other symptoms after playing in a river near the Todoroki Falls in southwestern Japan’s Kumamoto Prefecture has risen to 109, the prefectural government announced on Aug. 22.

The symptoms of all of the affected people were light, and they are all recovering, but the prefectural government is calling for caution, citing the possibility of an infectious disease spread by the river water.

According to the prefecture, seven high school students who had been playing near the waterfall on Aug. 13 all came down with symptoms of vomiting and diarrhea, and were seen by doctors. After this, other people who had been playing near the waterfall reported similar symptoms in succession.

The prefectural government installed signs at the site on Aug. 18 urging people to refrain from swimming. It has been investigating the cause of the problem since Aug. 19, checking the smell, transparency and pH of the water, among other items, but there were no abnormal water quality readings. An official with the prefectural government’s health crisis management division said they want to quickly identify the cause, and the prefecture is investigating the possibility of an infectious disease caused by bacteria or a virus.

The waterfall is managed by the prefectural government, and with a promenade and a suspension bridge managed by the Amakusa Municipal Government nearby, it is a popular river destination. In addition to swimming, many young people enjoy leaping into the water from rocks 5-6 meters high.

Yoshihiro Takayama, a member of the Division of Infectious Diseases at Okinawa Chubu Hospital, commented, “Considering that something which has not occurred before suddenly happened on the scale of 100 people, it’s natural to assume that microbes or other organisms were brought in by people from outside, rather than originating in the river.”

There is apparently a type of infection that can occur near water, leptospirosis, which spreads when the urine of infected animals such as mice enter the water, but in most cases, its symptoms are headaches and fevers, which are not consistent with the symptoms in the latest incident.

Takayama pointed out that unlike seawater, freshwater is easily contaminated. As a countermeasure against infections, he said, “I want people to avoid drinking water from lakes and rivers, and if they have symptoms like diarrhea, avoid playing in the water where people gather to prevent infection.”

(Japanese original by Keiko Yamaguchi, Kumamoto Bureau, and Maika Hyuga, Kyushu News Department)