August 21, 2008
Parasite Poses a Threat to Penguins
By Erica Gies
A parasite has been found in Galapagos penguins, raising fears among researchers that it could lead to avian malaria, a disease that contributed significantly to the 50 percent extinction rate of endemic birds in Hawaii.
The discovery resulted from a long-term study to monitor diseases in Galapagos birds, conducted by researchers from the University of Missouri, St. Louis, the St. Louis Zoo, Galapagos National Park, and the Charles Darwin Foundation.
Unlike Hawaii and other remote island archipelagos, the Galapagos, about 1,000 kilometers, or 600 miles, off Ecuador, retains 95 percent of its original species and all of its birds. "It's about the best record that exists on Earth," said Patty Parker, a professor of zoological studies at the University of Missouri, St. Louis, who discovered the parasite in the penguins.
Ninety-seven percent of the land is protected, and the surrounding waters make up one of the world's largest marine reserves.
Parker said the parasite was in the genus Plasmodium, which includes several malaria-causing species. The recently discovered parasite appears to be a new species and is so far unnamed.
The parasite was probably introduced by human activity, she said. Tourism has increased to 140,000 visitors in 2006 from 40,000 in 1990.
That has drawn immigrants from mainland Ecuador who work in the tourist industry, driving the population to an estimated 30,000 from about 8,000 in 1990.
In 2007, the archipelago, a Unesco natural heritage site, was labeled "in danger" by the international body.
The number of invasive insects arriving on the islands, presumably with the influx of people, has increased "exponentially," Parker said.
Recently introduced quarantines, which fumigate incoming passenger planes and the supplies of researchers headed for uninhabited islands, are encouraging to experts but not comprehensive. For example, there are no controls on private boats, and cargo ships are not treated the same as commercial tour ships.
Researchers do not yet know if the Plasmodium species in the penguins is a threat. The birds seem healthy.
That could be because that particular Plasmodium species does not cause malaria. Or the parasite could be biding its time, waiting to proliferate in the penguins during periods of stress, like a food shortage, other disease or the rainy El Nino, which causes insect populations to explode.
Researchers are trying to determine what sort of mosquito is transmitting the parasite to penguins. In Hawaii, the culprit was Culex quinquefasciatus, a species of mosquito that arrived in the Galapagos in the mid-1980s.
The other possibility is Ochlerotatus taeniorhynchus, a mosquito that may be native to the archipelago. This species can also carry the parasite that causes malaria.
Park managers would like to eradicate the guilty mosquito, and that may be possible with Culex because it needs fresh water to breed, a limited resource during the dry season. Ochlerotatus breeds in brackish water, however, which is found all over the islands, so eradication would be difficult.
Additionally, if the mosquito is native, it would be protected, said Dr. Virna Cedeno, director of the Fabricio Valverde Laboratory in the Galapagos. "It may not be as nice as a penguin," Cedeno said.
"But it would be a species to protect nevertheless."
Originally published by The New York Times Media Group.
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