Some might be surprised to find the most dangerous animals on earth are not lions, tigers or bears or even snakes.
The most dangerous animal in the world, according to Professor Scott Bernhardt a biologist at Utah State University, is the tiny mosquito which by some estimates kills 1 million people a year.
“Mosquitoes, the most dangerous animal on the planet, is not an uncommon statement,” he said. “How can that be true? How many lives world-wide are effected by a mosquito?”
Bernhardt, the director of USU’s undergraduate Public Health program in the Department of Biology, said besides mosquitoes there are sand flies, black flies and tics that also cause the spread of diseases.
“You look how many people die each year by being infected by flies and mosquitoes, maybe not so much here in the U.S., but in other countries,” Bernhardt said. ”Mosquitoes spread diseases such as malaria, dengue, West Nile, yellow fever, and Zika, which can kill millions of people around the globe annually.”
According to the Centers for Disease Control and Prevention, severe cases of West Nile virus have increased in the United States by nearly 25% since 2008, and dengue is a mosquito-borne tropical fever virus.
Dengue has risen 300% worldwide in the past 30 years.
Bernhardt’s current research is arthropod-borne infectious diseases and population genetics stems for the Centers for Disease Control and Prevention.
“The big concern we have is vector borne diseases; as the climate continues to warm up, mosquitoes, flies and tics will flourish,” he said. “As their populations grow the easier it is for mosquitoes and other insects to spread disease.”
The USDA’s Agricultural Research Service (ARS) is working to bring more weapons to bear against what they call one of the most dangerous creatures in the animal kingdom: the mosquito.
“Mosquitoes and flies are becoming more pesticide resistant,” Bernhardt said. “A lot of what we are talking about here is promoting safe ways to reduce populations of mosquitoes.”
Scientists are seeing mosquitoes world-wide becoming resistant to pesticides. So, they are looking for things found naturally to battle the insect.
“It is an interesting approach,” Bernhardt said. “It is not a new thought, but they are making real progress looking for natural ways to slow them down.”
Chemical pesticide control measures help reduce the mosquito population, but according to Jose Luis Ramirez, a research entomologist at the ARS Crop Bioprotection unit in Peoria, IL, an integrated approach that adds cultural and biological methods is the best mitigation strategy.
Chemical pesticides can quickly control an insect pest population, but drawbacks include persistence in the environment and insecticide resistance from targeted insects. The advantages of microbial control include reducing chemical pesticide use, improving crop quality, and reducing environmental contamination.
“Mosquitoes transmit diseases to humans, pets, and livestock,” Ramirez said. “Non-chemical control offers an environmentally friendly alternative to reduce the impact of mosquitoes on animal health and the annual economic losses to U.S. agriculture.”
Ramirez and his colleagues are evaluating fungi and bacteria that already exist in nature and turning these mosquito-killing microbes into biopesticides that target mosquito eggs, larvae, and adults. The process is similar to combating invasive plants by importing natural enemies from their homelands. Researchers identify beneficial microbes, test them for specificity against a target pest, then develop large-scale production for release against the pest.
Successful microbial biopesticides include Bacillus thuringiensis var. israelensis (Bti), a pathogenic bacterium that produces protein crystals that break open the mosquito larval gut when ingested, and Wolbachia, a bacterium that interferes with the reproduction of the yellow fever mosquito, Aedes aegypti.
“Non-chemical strategies allow farmers to practice pest control over vast areas without environmental contamination and the detrimental effects on beneficial insects, such as pollinators, that are important for crop production,” Ramirez said.
Although it’s now late in the season, there are still plenty of things people can do to reduce mosquito infestation, and it’s not too early to start thinking about next year.
“We are moving towards the end of the mosquito season for most places in the United States,” Ramirez said. “However, removing mosquito breeding habitats will not only help this season, but also remove eggs that could overwinter and become the new generation of mosquitoes next year.”