U.S. — The diseases that mosquitoes transmit kill hundreds of thousands of people each year, Scientific American reports.<br /><br />Female mosquitoes only bite humans when they require blood to feed their eggs. To suck blood, female mosquitoes use six needle-like parts, which scientists refer to as stylets. Two of these are called maxillae[m]; they are equipped with saw-like teeth that are able ot cut through human skin without a person noticing.<br /><br />Another set of needles, the mandibles[n], hold tissue apart to allow the Labrum[o] to dig through human skin in search for blood. Once it locates a source, it sucks it out.<br /><br />The hypopharynx[p] injects saliva into blood vessels, delivering chemicals that keep the blood flowing. <br /><br />Mosquito saliva causes blood vessels dilate, blocks a person's immune response and lubricates the proboscis. This results in a person suffering from itchy welts. During this process, dangerous viruses, such as Zika and West Nile virus, can be transferred into the human body.<br /><br />Texas, Colorado, Utah, Ohio, Indiana are all experiencing outbreaks of the West Nile virus, with the number of mosquitoes carrying the virus seem to be growing as well.<br /><br />About 1 in 150 people who are infected with West Nile virus develop severe illness that affects the central nervous system. About 1 out of 10 people who develop this illness die.
