Mosquito Larvae-Eating Fish Could Contribute to Malaria Control, Researchers Say
Fish that feed on mosquito larvae could help control mosquito populations that breed in seasonal pools, researchers from Tanzania's Tropical Pesticide Research Institute and the U.S.-based Poseidon Science Foundation said recently, SciDev.Net reports. According to SciDev.Net, the researchers are collaborating to determine the most effective method to mass produce and distribute fish embryos for use in malaria-endemic areas. If the strategy is effective, health programs could use the fish along with other malaria interventions such as insecticide-treated nets, insecticide spraying and artemisinin-based combination therapies.
According to SciDev.Net, although researchers in the past have suggested the use of fish to control malaria, these strategies targeted permanent bodies of water. However, many highly malaria-endemic areas experience a seasonal spike in malaria rates, often following a rainy season that creates pools where mosquito larvae can grow. Therefore, the researchers from TPRI and PSF have identified a Tanzanian fish species -- called Nothobranchius guentheri -- whose embryos persist in a state of suspended animation when water recedes. Although adult N. guentheri die every year, the embryos can survive in pools as small as depressions made by elephant feet, SciDev.Net reports. The embryos then hatch at the start of the rainy season and feed on mosquito larvae, which hatch around the same time.
According to Shandala Msangi, lead researcher at TPRI, once the fish become established in a particular pool, they "will continue to come back year after year to feed on the mosquito larvae." Msangi added that the team's research on using native annual fish as natural predators is part of a new trend "to explore indigenous technologies and resources." Eliningaya John Kweka, senior scientific officer of medical entomology in TPRI's mosquito department, said the researchers "expect to have very good exciting results in this study in reducing malaria spread in Tanzania" because local communities understand the benefits of mosquito control measures.
However, Storn Kabuluzi, preventive health services controller and former malaria control manager in Malawi, said the fish embryo-based intervention might be costly and difficult to implement in Tanzania's widespread malaria-endemic regions. In addition, challenges remain in securing significant and continuing support to conduct studies and sustain a long-term program, Kweka said. He added that although the PSF supports the team's research efforts, the program will need a consortium of participating organizations and countries to implement the interventions (Mkoka, SciDev.Net, 4/15).