African fish can beat malaria
2007-08-10 07:15
London - A nutritious fish eaten in
Kenya could be used as a weapon against malaria, according to a
study of three fish ponds where the species nearly wiped out
mosquitoes that transmit the deadly disease.
Researchers have long known that the Nile tilapia feeds on
mosquito larvae but the study was the first to test its
potential to fight the disease in the field, said Francois
Omlin, a researcher at the International Centre of Insect
Physiology and Ecology in Nairobi.
"A fish in the field may act differently than a fish in an
aquarium and it was important to test how effective it could
be," Omlin, who led the study, said.
"The tilapia species was never tested in the field for its
ability to eat mosquito larvae."
Malaria, caused by a parasite carried by mosquitoes, kills
more than one million people a year worldwide and makes 300
million seriously ill. Ninety percent of deaths are in Africa
south of the Sahara, mostly among young children.
The disease has become resistant to some drugs and work on
a vaccine has been slow. Bed nets, insecticides and anti-malarial
drugs are effective ways to combat malaria and this study
represented another potential protection, the researchers said.
The team, which published the findings in the BioMed
Central journal on Thursday, chose the tilapia because it was native to Kenya and had a reputation as a mosquito eater, Omlin said.
In the study, the team cleared three ponds of fish and
vegetation in the highlands of Western Kenya and measured the
mosquito population before introducing young tilapia.
Ten days later, no malaria mosquito larvae were recorded
compared with a similar pond with no tilapia, and 41 weeks
after the fish were introduced the number of mosquitoes fell by more than 94%, Omlin said.
The problem, however, was that many fish ponds in the
country were poorly maintained or lacked fish, which made the
stagnant pools of water prime breeding ground for mosquitoes
and raised the risk of malaria, Omlin said.