Insect repellents: effect of mosquito and repellent-related factors on protection time.

The effect of factors like mosquito size and vigor, nutritional state, different mosquito batches from the same population, mosquito density, and repellent dose on the protection time of repellents was studied. The size and vigor of mosquitoes did not affect protection time. Mosquitoes recently gorged on sugar water took significantly longer to bite through repellent than starved ones. The protection times of repellents with different batches from the same mosquito population were similar but varied significantly with different populations. Mosquito density affected the protection time significantly. Repellents failed sooner in high density cages. Regarding the effect of repellent dose on protection time, higher dosages gave less variable results than lower dosages.