Malaria makes mosquitoes more likely to suck human blood

study, published in the bioprint server
, found that mosquitoes seem to prefer to suck human blood when they carry malaria. This is another obvious example of parasites directing host behavior.
nature is full of stories of parasites manipulating the organisms in which they live for their own ends. Eyeworms, for example, allow fish to swim close to the surface of the water, allowing them to be caught by birds. Some wasp larvae live in other wasps and turn them into "zombies". The infamous toxoplasma parasite makes rodents fearless, allowing them to be eaten by cats and possibly leading humans to some dangerous behavior.
single-celled sickle malaria parasite is transmitted by mosquitoes, but it can only reproduce and develop in humans and a small number of apes. If a mosquito carries it to a cow or sheep, it will die.
, the sickle malaria parasite plays a lot of tricks to help prolong its life. Infected humans are more attractive to mosquitoes. Mosquitoes infected with the immature stage malaria parasite eat less to stay away from danger. Mosquitoes infected with the malaria parasite, which is in the transmission stage, eat more.
Aamélie Vantaux and colleagues from the Bobo-Diuraso Institute for Health Sciences in Burkina Faso wondered whether parasites in the infection phase could also drive mosquitoes to look more for human hosts than for other food sources.
set traps in three rural areas of the country and put baits that smelled of humans and calves, respectively. The researchers analyzed blood in the mosquito's intestines to test the presence of the malaria parasite and determine which animals they had caused it to feed on.
the mosquito's infection did not affect which trap they would be attracted to, but appeared to be associated with which animal the mosquito had bitten. Of the mosquitoes carrying the malaria parasite, 77 per cent had been feeding on humans. This proportion is 64 per cent among mosquitoes carrying malaria parasites that are not infected. The proportion of unseeded mosquito bites on humans was essentially the same, at 61 per cent.
the tests did not find an effect on mosquito odor preferences, there are certainly other effects to explain why mosquito bites on humans increase. When mosquitoes rely on visual or other sensory information to find targets, perhaps parasites affect their close-up behavior, Vantaux said. Or, it may change their choice of habitat or pattern of activity. "They may stay in the house longer after biting humans. Or, infected mosquitoes adjust their peak activity to be more accessible to humans. (Source: Science Network Xu)