Over the last few years, there has been a rise in the number of cases of diseases caused by mosquito and tick bites. The U.S. Centers for Disease Control and Prevention (CDC) has said that a natural chemical compound could help combat this problem. This compound Nootkatone is found commonly in cedar trees, and grapefruit skin says the organization.
Problem of insecticide resistance
Several diseases such as malaria, yellow fever, Japanese encephalitis, Dengue, Zika and Chikungunya, elephantiasis, or filariasis are vector-borne. This means that these protozoal and viral infections commonly spread due to bites from infected mosquitoes. Ticks are known to spread deadly infections such as West Nile Virus and Lyme disease. In recent years these insects have become resistant to the commonly used insecticides used to reduce their population and prevent the spread of these infections. Notable resistance among mosquitoes is seen against Dichlorodiphenyltrichloroethane, commonly known as DDT.
Dr. Kristy Murray, from Baylor College of Medicine, said, "Insecticide resistance, of course, is a problem that we have to tackle constantly. And so when we use different things, and they become less and less effective, we need to come up with novel ways of doing so. And this is something that helps us to do that."
Outdoor activities and risk of bites
Due to the COVID-19 pandemic, most of the gatherings and activities have shifted outside to maintain the physical distancing measures and prevent the spread of the coronavirus infection. Experts have said that with more people spending time outdoors, the risk of mosquito and tick bites are on the rise as is the risk of getting infected with one of the infections mentioned above.
Dr. Murray said, "We're moving all of our events outside. And people are more active outdoors as well they're going to have more mosquito exposure, they're going to have more tick exposure. And so there's a lot of things that we need to do to prepare people and help to protect them as well."
Some of the CDC approved recommendations to prevent mosquito and tick bites include:
- Wearing long-sleeved shirts and long pants to reduce exposed skin.
- An Environmental Protection Agency (EPA) registered insect repellent should be sprayed or smeared over the exposed areas of skin
- In case of exposure risk to the sun, the experts recommend the use of sunscreen first and insect repellent over that.
Nootkatone approved in insect repellents
The researchers have found that Nootkatone is a naturally occurring compound in cedar trees and grapefruit skin. It is the reason behind the smell and taste of grapefruits and is thus used to make fragrances.
This Monday, the EPA approved this new chemical in insect repellents that can prevent mosquito and tick bites and also kill the insects. Nootkatone is oil and has been found to be safe for use over the skin and also in perfumes and even food. It is non-toxic to humans, and other mammals, birds, fish, and bees said the EPA in its statement. It is effective against insects that are resistant to DDT, pyrethroids, and other insecticides.
The EPA registration is for products with Nootkatone as an active ingredient, the statement said. All future products and formulations would need to be retested and re-registered, said the agency. The product may also repel other insects, causing diseases such as sand flies, lice, midges, etc.
Alexandra Dapolito Dunn, the EPA's assistant administrator for the Office of Chemical Safety and Pollution Prevention, said, "This new active ingredient has the potential to be used in future insect repellents and pesticides that will protect people from disease. In many areas of the United States, mosquitoes have become resistant to currently available pesticides. A new active ingredient in our toolbox will help vector-control programs."
According to public health entomologist Manuel F. Lluberas nootkatone could be more acceptable to the general public due to its natural origin. He said many were skeptical of using chemical and synthetic products on their skin. He hoped that this new repellent could be bought by foreign aid programs like the President's Malaria Initiative in a more cost-effective manner.
Ben Beard, deputy director of the division of vector-borne diseases at the CDC said that the scent of the product is pleasant, and it is effective. "If you drink Fresca or Squirt, you've drunk nootkatone," Dr. Beard said.
Duane J. Gubler, former CDC chief of vector-borne diseases, said, "Its use as an insecticidal soap has great potential."
Joel R. Coats, an insect toxicologist at Iowa State University, said his previous work on Nootkatone showed that it was "an impressive repellent" but poor insecticide. The CDC however, says that the compound is capable of killing the insects as well. Coats further added that other plant-based repellents like citronella, lemongrass oil, peppermint lose their potency in around an hour. This is not true for Nootkatone.
Dr. Beard said there have been "folk tales that cedar repels insects — and people keep their clothes in cedar chests," and research 25 years back showed that Nootkatone could work as an insect repellent. Dr. Beard added that how it works is not clear, but theories are that Nootkatone could activate octopamine receptors in the insects that send electrical impulses. This causes uncontrollable twitching in the insects, which finally kills them. He added that this new repellent got financial support from BARDA, the Biomedical Advanced Research and Development Authority.
Dr. Jay Butler is deputy director for infectious diseases at CDC said, "CDC is proud to have led the research and development of Nootkatone. Providing new alternatives to existing bite-prevention methods paves the way to solving one of the biggest challenges in preventing vector-borne diseases -- preventing bites."