In the last several weeks, San Diego County’s Health and Human Services Agency, HIV, STD and Hepatitis Branch has documented a cluster of shigellosis cases among men who have sex with men (MSM).

A March 14 e-mail bulletin was sent by the San Diego County’s HIV, STD and Hepatitis Branch alerting health professionals that several cases of shigella diarrheal illness have been identified among MSM. According to the e-mail bulletin, some MSM have reported meeting sex partners through the Internet.

Public health officer Nancy Bowen said the county has identified a total of six cases among MSM so far this year.

According to the Centers for Disease Control and Prevention (CDC), shigellosis is an infectious disease caused by a group of bacteria called shigella. Those infected with shigella develop symptoms such as diarrhea (three or more loose or watery stools in 24 hours), fever and stomach cramps one to two days after they are exposed to the bacterium. The diarrhea is often bloody.

Bowen said there has been a total of 21 cases of shigellosis documented this year in San Diego. She said the county did not track how many were among MSM in 2005, but there were a total of 207 shigellosis cases overall.

Shigella bacteria are spread through direct or indirect fecal-to-oral contact. The CDC recommends people with shigellosis should abstain from sexual behavior that is likely to transmit the infection for at least three days after the initiation of antibiotic treatment or until a negative culture is obtained. Some people who are infected may have no symptoms but may transmit the shigella bacteria to others.

“It’s sexual practices with either oral/anal contact or using sex toys or something else and not washing their hands,” said Terry Cunningham, chief of the HIV, STD and Hepatitis Branch. “… The bacteria are kind of hardy in the sense that it doesn’t take a lot of bacteria to get you infected. It can pass through the acid environment in your stomach pretty successfully, so small amounts of bacteria can be infectious and will cause disease.”

The CDC recommends patients wash the perianal area, other body parts and sex toys with soap and water before and after sexual activity.

Cunningham said identifying shigellosis among MSM is important since an outbreak occurred in San Francisco in 2000. The San Francisco Health Department reported that shigella sonnei, one of several different kinds of shigella bacteria, occurred among MSM with 230 culture-confirmed cases reported from June to December of that year. Among those cases, 55 percent were among HIV-positive individuals and 31 percent reported blood in their stools. The average duration of illness was seven days.

Shigella sonnei, also known as “group D” shigella, accounts for over two-thirds of shigellosis infections in the U.S., while a second type, shigella flexneri, or “group B” shigella, accounts for almost all of the rest, the CDC said.

Shigellosis usually resolves itself in five to seven days. But in some people, especially among young children and the elderly, the diarrhea can be so severe that the patient needs to be hospitalized, according to CDC data.

Cunningham said shigella can often be resistant to different medications. He also said diagnosing shigellosis is difficult because doctors may not be obtaining cultures before prescribing the antibiotic treatment. The county health department recommends the antibiotic ciprofloxacin. The treatment regimen calls for 500 milligrams of ciprofloxacin for three days.

“It’s just an early warning, so it may be nothing,” Cunningham said. “When we do this [type of case investigation], we find out there are some cases out there. Because, again, a lot of doctors probably aren’t doing the cultures, they’re just saying ‘Well, you got diarrhea’ and they give you some medication – so we wouldn’t know.”

People with HIV/AIDS who get shigellosis may develop other problems and should be closely monitored, Cunningham said.