Bacteria can infect humans
Profile of Streptococcus iniae

by Terry Ally

BARBADOS, Oct 13/99 - The bacteria which prompted the Barbados government to temporarily close the pot-fish fishery, and place a ban on the consumption of the fish, is a very serious bacteria which can cause meningitis and other illnesses in human beings.

Streptococcus iniae have been known to cause cellulitis, infective endocarditis, meningitis, and probable septic arthitis in human beings who handled infected fish.

The bacteria occur naturally in the environment and in low levels in the fish's brain but given the right conditions they can rapidly multiply and cause meningitis in the fish. Humans also have bacteria in their stomachs which perform a useful role but if we eat the wrong types of foods the right conditions will be created for them to rapidly multiply and make use sick.

Identifying the bacteria is only one-third of the problem solved. The other two pieces of the puzzle? To find out the reason for the explosion of S. iniae and whether other seemingly healthy fish are safe to eat before the fishery can be reopened.

Previously, the bacteria were reported only in fresh water fish but in recent times, the disease struck in salt water fish. More alarmingly they crossed the barrier from fish to human beings.

Coincidentally, S. iniae was named after the fish in which they were first found - the Amazonian dolphins named Inia geoffrensis. Perhaps the conditions which caused the bacteria to rapidly multiply in the Amazon could have travelled with fresh water lenses from South America to the Caribbean.

In 1986, S. iniae, which was then reported as S. shiloi was identified as a cause of meningoencephalitis among tilapia and trout in Israel, then later identified among tilapia in the United States and Taiwan.

Human infections

The first recognized case of S. iniae infection in humans occurred in Texas in 1991, and a second case occurred in Ottawa, Canada, in 1994 however, potential sources for both cases were not determined.

The in December 1995 three people were infected with the bacteria with a fourth in February 1996 - all in Ontario, Canada. All four were Chinese who were preparing fresh fish.

Three were healthy women, aged 40 to 74. One punctured her hand with a fish bone, the other cut her finger with a knife just used to clean fish, and the third was pricked by a dorsal fin.

Symptoms started from 16 hours to two days and included high fever and cellulitis. They were all treated with antibiotics and recovered.

The fourth patient, a 77-year-old man, was admitted to the hospital on February 1, 1996, because of a 1-week history of increasing knee pain, intermittent sweats, fever, dyspnea, and confusion. He had  infective endocarditis, meningitis, and probable septic arthritis.

In three cases the fish involved were tilapia, all purchased from different stores, and in two cases the fish were taken live from holding tanks and appeared healthy.

While the fish kills were on, the government advised Barbadians to stay away from pot-fish and now that the cause is known and the seriousness of it, they have temporarily closed the fishery, advising Barbadians not to catch or eat the reef fish, until further notice.

Possible Illnesses

Infective endocarditis is a disease caused by infection of the lining of the heart. Its characteristic lesion is a cluster of growing bacteria which develops on a heart valve. Depending on the type of bacteria, it could cause damage to the valve, pieces could get stucked into an artery that goes to a big organ and create clotting, stroke, heart or kidney failure. This illness can be treated.

Meningitis is an acute inflammation of the membranes covering the brain or spinal cord, or both. Bacteria meningitis is not highly contagious and can be spread through direct contact with nose and throat secretions. Healthy persons, who have no signs of illness, can have these bacteria in their nose or throat and spread them to others. Sharing a glass, cup or eating utensil, coughing or sneezing into the face of another person, or sharing a cigarette are examples of how contact with another person's respiratory secretions might occur. Meningitis can produce mild symptoms - such as headache, low-grade fever and tiredness lasting two to three days - in some patients. In other patients, the symptoms can be severe and begin suddenly with fever, headache and stiff neck accompanied by some combination of other symptoms: decreased appetite, nausea, vomiting, sensitivity to bright light, confusion and sleepiness. This illness can be treated.

Septic arthritis is infection related inflammation of one or more joints and can be treated.

Cellulitis is an inflammation of the skin's connective tissue, found especially in children, and can be treated.

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