Millions of turtle eggs exported from the United States to be hatched and the turtles sold as pets may harbor strains of salmonella bacteria that are resistant to antibiotics and could pose a serious international health threat to young children, U.S. and Canadian health officials say.
Salmonella carried by healthy reptiles and livestock can infect people and cause severe abdominal cramps, nausea, diarrhea and vomiting. The condition is rarely fatal in adults, but in young children it can require hospitalization.
In an attempt to produce salmonella-free animals, turtle farmers have turned to antibiotics. But a study published recently in the American Journal of Epidemiology found that the practice is promoting the emergence of resistant bacterial strains that can be transmitted to children playing with a pet.
Dr. J. Y. D'Aoust, a scientist at Health and Welfare Canada, and his colleagues reported that they sampled 28 lots of turtle eggs imported in 1988 from four farms in Louisiana.
Six lots, or about 40,000 eggs, were found to be infected with salmonella. The scientists isolated 37 different species of salmonella in the eggs and found that 30 were resistant to gentamicin, the most commonly used antibiotic.
"Such high levels of antibiotic-resistant salmonellae in turtle eggs pose a serious human health risk," the study concluded. "Further marketing of turtle eggs and hatchlings should be curtailed until consistent production and distribution of salmonella-free stocks can be assured."
In 1975, the Food and Drug Administration banned the domestic sale and distribution of turtles less than 4 inches long after scientists found that nearly 15 percent of the human salmonellosis cases in the United States could be attributed to contact with these pets. Exporting turtles is not prohibited.
"Since the FDA ban was passed, turtle-associated salmonellosis has ceased to be a problem in the United States," said Robert V. Tauxe, an epidemiologist at the federal Centers for Disease Control in Atlanta.
Dr. Tauxe said that baby turtles are "biological sponges" of salmonella.
A few countries, including Canada, have banned imports of baby turtles, but exporters have sidestepped that law by shipping turtle eggs.
Leon Boudreaux, a spokesman for about 30 turtle farmers and shippers in Louisiana, said that about 5 million baby turtles and turtle eggs were exported to Europe, Asia and South America last year, amounting to more than $2.5 million in sales.
Louisiana requires that an independent laboratory certify that turtle eggs are salmonella-free before export, but a lot that tested positive for salmonella in the Canadian study had such certification.
C. T. Raby, an assistant commissioner of the Louisiana Department of Agriculture and Forestry, said the Louisiana Office of Animal Health Services would investigate the issues raised by the study.