In the first survey of sand flies in Panama to use genetic
barcoding, scientists at the Smithsonian Tropical Research
Institute and Gorgas Memorial Laboratories identified 20 sand fly
species from Barro Colorado Island. Two species carried
Leishmania naiffi, a parasite that causes cutaneous
leishmaniasis: persistent, itchy skin lesions. Three species
carried Wolbachia, a bacterial parasite of insects that
could contribute to a strategy to control the flies and limit
disease transmission.
"We used DNA barcoding—sequencing a particular gene of the
blood-feeding flies we collected—to identify the 20 fly
species; two species could not be distinguished visually," said Don
Windsor, a Smithsonian scientist, who collaborated with STRI
interns Jorge Azpurua, Dianne de la Cruz and Anayansi Valderama.
"By characterizing another gene fragment from the nucleus of
Leishmania, we discovered which fly species carried this
disease-causing trypanosome."
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Leishmaniasis is not new in central Panama—it poses a
long-standing health risk to residents and visitors in the region.
L. naiffi, the species carried by the flies in this survey,
was previously known only to be in the Caribbean and the Amazon.
"Other species of Leishmania and the blood-feeding flies
that transmit them are endemic in central Panama," said Windsor.
"Either L. naiffi was here undetected, or it could be a
recent introduction carried by animals or people coming into
Panama. Another explanation is that it is gradually moving
northward from South America into Central America."
Researchers hope that the presence of Wolbachia in the
same species of flies that carry Leishmania may be useful in
disease control. Wolbachia bacteria infect the flies and are
passed readily from generation to generation. Wolbachia
affects the flies' ability to reproduce and has been proposed as a
possible biological control of other insect pests.
Windsor emphasized that common preventative measures such as
wearing insect repellent and long-sleeved shirts and pants when
going out at dawn or dusk should be standard practice for
residents, researchers and tourists who visit lowland tropical
forests where Leishmania is endemic.
SOURCE