A form of neurologically harmful bacteria may be to blame for the majority of beached dolphins washing from the Pacific Ocean onto Costa Rican shores.
A recent sampling of 19 dolphins found dead from being stranded on land show that all of them showed signs of neurological distress and that 15 of them tested positive for the presence of antibodies for the dangerous bacteria brucella. That bacteria can produce disease in the central nervous system causing disorientation and problems with flotation, both which can cause a dolphin to become beached. Furthermore, in eight of the dolphins sampled scientists were able to isolate the actual bacteria, according to new research.
The study was conducted by Edgardo Moreno Robles, a specialist in immunology, cellular microbiology and infectious diseases at the veterinary school of the Universidad Nacional in Heredia.
The results caused him to conclude that the bacteria is highly present in populations of dolphins in Costa Rican and nearby waters and more than likely the cause behind their beaching. Another study that analyzed a bank of dolphin samples in Florida indicated 35 percent tested positive for the bacterial antibodies.
The presence of the bacteria and the health of the local dolphin population can have consequences that extend further than the dolphin realm. According to the Centro de Investigación en Enfermedades Tropicales the bacteria can affect other aquatic mammals as well. This fact has serious ramifications for the ocean habitat and indirect consequences for the sector of the national economy dependent on marine tourism, the center concluded.
Also, the bacteria can also cause illness in pigs, cows, sheep goats and household pets, affecting their productivity and reproductivity. The ingestion of their untreated products or prolonged contact with an infected animal, its tissues or byproducts can also cause complications and crippling disease in humans, Robles said in a press release. In humans, the bacteria is known to directly cause meningitis, chronic fatigue, encephalitis, fever and abscesses.
The disease most commonly infects veterinarians, butchers, farmers, laboratory workers or consumers of raw goods.
The most common disease directly caused by the bacteria is brucellosis, which is found in the domestic livestock.