Via CIDRAP: NEWS SCAN: Uganda Ebola update, Ebola research hiatus, resistant mosquitoes, novel NDM strain. Click through for all the reports and excellent links. Excerpt:
Mosquitoes that harbor the malaria parasite in Cote d'Ivoire were found resistant to all approved classes of insecticides, according to a study today in Emerging Infectious Diseases.
Researchers from the UK's Liverpool School of Tropical Medicine tested hundreds of Anopheles gambiae mosquitoes for sensitivity to approved insecticides using World Health Organization susceptibility criteria, which define resistance as producing less than 80% of mosquito deaths 24 hours after a 1-hour exposure to the insecticide.
Death rates by insecticide were: fenitrothion, 74.0%; deltamethrin, 31.9%; permethrin, 24.0%; bendiocarb, 12.4%; and DDT, 8.2%. Thus, the mosquitoes were resistant to all five repellents. The team also found an "unexpectedly strong" resistance phenotype to deltamethrin and bendiocarb in the mosquitoes.
The authors said that determining the selective pressure responsible for the resistance is difficult, given that the use of insecticide-treated bed nets in the region where the insects were collected is similar to their use in other parts of Africa.
They concluded, "The implications of this resistance scenario for malaria control are severe. With no new classes of insecticides for malaria control anticipated until 2020 at the earliest, program managers have few options available when confronted with multiple-insecticide resistance."