Mosquitoes are flourishing in this summer's heat wave. Medical entomologist Cameron Webb shares some tips on repelling mozzies – and busts a myth or two.
Photo: Pixabay
It's the female insect that bites, using a nutritional hit from the blood of her victim to help develop her eggs.
The male of the species feeds on plant juices.
Some mosquito species bite humans – others prefer animals, birds, frogs or reptiles.
Insect repellent creams and lotions containing DEET, picaridin or oil of lemon eucalyptus work well if you apply an even coat over all exposed areas of skin, says Webb.
"If you miss a bit or you're just putting on a dab here and there the mozzies will find a way through."
Experts are still not entirely sure why DEET works but Webb supports the theory that it switches off mosquitoes' appetite to feed.
The concentration of DEET determines how long it lasts.
Products containing 80 percent DEET can stop mosquitoes biting for 15 hours while lower dose creams still provide protection but for a shorter time, says Webb.
Insect control systems that plug into a power socket are essentially smokeless mosquito coils which kill mosquitoes rather than simply repelling them.
Those containing pyrethrins are toxic to fish, so it's recommended to cover any fish tank in the room.
"There's no indication that I've seen that they're posing a health risk [to people] and they're probably much less of a health risk than the mosquito coils we're used to using."
Cameron Webb: mosquito expert Photo: Twitter @Mozziebites
Webb has bad news for those who believe gin or garlic has the power to keep mosquitoes away.
"There doesn't seem to be any evidence whatsoever that anything that you eat or drink will be able to completely stop mosquitoes biting you.
"You can enjoy your gin and tonic, but just don't expect it's going to stop you being bitten by mosquitoes."
Quinine isn't present in tonic water in concentrated enough amounts, and in any case, says Webb, it was used to treat malaria not repel mosquitoes.
And what of apps that suggest you can use sound to repel mosquitoes?
"None of it works," says Webb. "Avoid those."
Although some people seem to get bitten more than others, Webb says this may not actually be the case.
"Just because two people react differently it doesn't mean one person has necessarily had more bites than another."
It might be that one person has a more severe reaction to the saliva injected by the female mosquito, he says.
Research is being carried out into whether the severity of the reaction to a bite correlates with an increased likelihood of getting infected by a mosquito-borne pathogen.
In New Zealand, mosquitoes are generally free of deadly pathogens and more likely to bite in the afternoon or night, says Webb.
But in tropical regions, including the Pacific, some mosquitoes carry serious diseases – such as dengue fever, chikungunya virus and the Zika virus – and generally bite in the daytime, so travellers need to take precautions during the day.
