The Helsinki Department of Social Services and Health Care has announced that sexually transmitted disease infection cases are on the rise among men engaging in unprotected gay sex.
Seven cases of hepatitis A, an infectious liver disease, have been recorded in Helsinki since January 26.
"That is far too many in such a short time period," says epidemiology chief Hannele Kotilainen.
An epidemic of hepatitis A has been observed in Europe among men engaging in unprotected gay sex since early last year.
The hepatitis A virus has an incubation period of some 15-50 days, meaning that further cases may still come to light. Symptoms include nausea and lack of appetite, followed by fever, stomach pains and fatigue. One week after initial symptoms carriers begin to present with yellowness in the skin and eyes.
The hepatitis A virus is transmitted through close physical contact, including unprotected sex. The virus can also be caught from food, water or goods contaminated by faecal matter.
The hepatitis A disease clears up unaided, but in adults recovery from the illness can take months. At-risk patients may require hospital care if they develop a liver inflammation.
There is a vaccine against hepatitis A that grants lifelong immunity.
"Ask your doctor for the vaccine if you have never had hepatitis A, and especially if you have a chronic liver disease or other condition that compromises your immune system," Kotilainen says.
Gonorrhea infection rate highest in 22 years
Other STDs in addition to hepatitis A have also become more prevalent among gay men engaging in unprotected oral and anal sex in Helsinki in the course of a few years.
For instance, last year there were more cases of gonorrhea in the Helsinki and Uusimaa medical district than have been registered in the last 22 years. More than 200 cases of gonorrhea were recorded, compared to some 120 in 2015. Two thirds of gonorrhea patients were 20-40-year-old men.
More than 60 percent of the infections took place as a result of unprotected gay sex, the health care department figures show. Nearly 75 percent of syphilis cases were transmitted in this way.
The city's healthcare department warns the public that syphilis's resistance to antibiotics has increased Europe-wide, with cases of antibiotic resistance already reported in the UK.
Doctor Kotilainen says that treating gonorrhea has become more difficult in Finland. One oral tablet has thus far been a sufficient cure for the disease, whereas now many cases require antibiotics to be injected into muscle tissue.
Kotilainen says that if the situation deteriorates, gonorrhea will require an intravenous medical procedure to be treated.