Vibrio bacteria could be a risk to fish as well as humans

About half of new marine vibrio bacteria discovered in the last five years, can kill fish and crustacea, according to researchers at Heriot-Watt University in Edinburgh.

The most common disease of vibrios is cholera, which has caused millions of cases of illness and fatality in humans. Recent interest in this genus of bacteria has led to the discovery of many new species, especially from seawater and marine animals.

New species have been found in a wide range of marine environments, including corals, sediments and rotifers. For example, Vibrio coralliilyticus has recently been described as a new cause of disease in coral.

Professor Brian Austin of Heriot-Watt University said that his research demonstrates that some of these new species are similar to existing fish and shellfish pathogens. The new species, Vibrio brasiliensis, seems to be related to Vibrio tubiashii, which has long been known to cause disease in oysters.

Professor Austin comments: “Having observed this, the question arose about whether any of these new species could have implications to the health of marine animals. The answer was that around half of the new species killed fish in laboratory conditions. Our research shows that marine vibrios could cause disease to fish and crustaceans. In some cases, only 100 bacterial cells from the pathogens were capable of causing disease. This means that the bacteria are extremely aggressive and could pose a great risk to sea animals, as disease is often caused by enzymes produced by bacteria.”

It is not yet clear to what extent these new vibrios affect marine animals in the wild. The next thrust of the work by Professor Austin and his team is to devise methods to minimize the risk of these bacteria to animals and the environment.