Mosquitoes infect humans with the Zika virus, yellow fever, dengue, malaria, and other diseases. Why are they so dangerous and what’s being done about it? Share on Pinterest Mosquitoes have bedeviled humans for centuries, spreading disease and death to millions. Today, the latest plague they bring is the Zika virus. “Mosquitoes are perhaps the most dangerous animals in the world,” Omar Akbari, PhD, an assistant professor of entomology at the Center for Disease Vector Research at the University of California Riverside, told Healthline. “They are the primary vectors for major human diseases such as yellow fever, malaria, and dengue fever, which together infect hundreds of millions of humans worldwide and kill millions each year.” The World Health Organization, he added, reports that more than 50 percent of the world’s population is presently at risk from mosquito-borne diseases. Zika and other insect-borne diseases are traveling quickly with new reports every week. On February 2, Texas reported a case of Zika infection transmitted by sex, rather than by a mosquito bite. The patient was infected after sexual contact with someone who had returned from Venezuela, where the virus is spreading. On February 9, the big island of Hawaii declared a state of emergency to deal with an outbreak of dengue fever, spread by infected mosquitoes. Since October, 250 cases have been confirmed on the island. Read More: United States Warned to Brace for Zika Virus »

Mosquitoes Tough to Fight Current methods of preventing mosquito-borne diseases are highly inefficient, Akbari said. While crucial mosquito research is under way in university labs, the U.S. Centers for Disease Control and Prevention (CDC) is also engaged in the global war against life-threatening diseases. Dr. Lyle Peterson, MPH, leads the CDC’s fight against insect-borne diseases. Peterson is director of the Division of Vector-Borne Diseases in the National Center for Emerging and Zoonotic Infectious Diseases in Colorado. The center supports the CDC’s mission to protect the American public from exotic and domestic bacterial and viral pathogens transmitted by mosquitoes, ticks, fleas, and other vectors. Peterson told Healthline that the Zika virus was discovered in the mid-20th century in Africa. “In 1947, the virus was first isolated from a rhesus monkey found in the Zika forest of Uganda,” he said. “Before 2007, at least 14 cases of human Zika virus disease had been documented in the literature, although other cases were likely to have occurred and were not published.” Read More: Dengue Fever Outbreak in Hawaii May Last Through Summer Tourist Season »

Mosquitoes Are Effective Transmitters Since Zika was first reported in Brazil in 2015, cases have exploded in 24 countries or territories. The virus is spreading rapidly because mosquitoes are more effective transmitters of disease than even flies. “Mosquitoes spread disease-causing agents, not the disease,” Peterson said. “They bite people to consume blood. Feeding allows the mosquito to produce eggs. When feeding, a mosquito pierces the skin like a needle and injects saliva into a person’s skin. This allows the disease-causing agent – for example, the Zika virus – into the site.” Only a small fraction of fly species, however, will bite people, Peterson said. When a fly bites, it creates a wound and drinks blood from the site. “When a fly bites, it does not directly inject saliva into the bite like a mosquito does,” Peterson explained. “Some diseases are transmitted by flies. But because fly feeding habits are different from mosquito biting habits, fewer pathogens are transmitted through fly bites.” Since mosquitoes fly, they can also spread a disease more quickly than an illness such as Ebola, which is transmitted from person to person. Read More: Scientists Find Gene Editing with CRISPR Hard to Resist »