Can genetically modified mosquitoes reduce disease?

In the current year, the CDC has reported over 3 million cases of dengue fever in the Americas, including over 882 cases in the United States. This marks the second-highest annual rate of dengue fever in the Americas since 1980.

Dengue fever is transmitted by mosquitoes, particularly in areas with hot and humid climates. These conditions have become more common due to record-breaking heat and extreme weather patterns in recent years, leading to an increase in dengue cases, as noted in Nature.

Experts view this surge in dengue cases as a warning sign of broader environmental changes, including shifts in rainfall patterns and rising temperatures.

In the United States, the number of dengue cases has risen significantly, going from 814 cases in 2021 to 2,261 in 2022, with over 50% of these cases originating locally. Dengue has been spreading in states like California, Florida, Texas, and New York. This trend is expected to continue, driven by climate change and urbanization.

Dr. Krutika Kuppalli, an infectious disease physician and chair of the Infectious Disease Society of the Americas Global Health, expressed concern about this situation. She suggested that factors such as climate change facilitating mosquito vectors, reduced surveillance due to resources being directed toward COVID-19, and increased testing due to similar symptoms between dengue and COVID-19 may all contribute to the rise in cases.

Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security, emphasized that the United States is not immune to mosquito-borne diseases and that this should not be underestimated.

What is Dengue Fever? Dengue fever is a viral disease transmitted to humans through Aedes mosquitoes. These mosquitoes also transmit other viruses like Zika and chikungunya. Individuals can contract dengue multiple times during their life, according to the CDC.

Most dengue-infected individuals experience mild or no symptoms. Symptoms, if present, usually manifest 4-10 days after a mosquito bite and last for 2-7 days. Common symptoms include headaches, high fever, muscle and joint pain, nausea, vomiting, swollen glands, and rash.

Mild symptoms can resemble other illnesses that cause fever, aches, pains, and rashes. Severe cases of dengue are rare but can progress rapidly and become a medical emergency. Severe symptoms may include severe abdominal pain, rapid breathing, increased thirst, bleeding in vomit or stool, pale and cold skin, persistent vomiting, bleeding in gums or nose, and weakness. Those with severe symptoms should seek immediate medical attention.

Currently, there are no antiviral treatments for dengue. Patients receive supportive care, including fluids and medications to manage pain and reduce fever (e.g., acetaminophen). It is advised to avoid aspirin and ibuprofen, which can increase the risk of bleeding, according to the CDC and WHO.

And are they vaccinated? A dengue vaccine is available and approved for use in children aged 9-16 who have previously had laboratory-confirmed dengue infection and live in areas where dengue is prevalent. This includes U.S. territories such as American Samoa, Puerto Rico, and the U.S. Virgin Islands. The vaccine is particularly beneficial for those who have had one type of dengue infection previously. However, it is not approved for Americans simply traveling to high-risk dengue areas.

And how do we prevent it? The primary method to prevent dengue infection, especially in areas where it is prevalent, is to avoid mosquito bites, according to the CDC. Preventive measures include wearing protective clothing, using insect repellent containing DEET, Picaridin, or IR3535, using mosquito nets, and installing window screens.

Can genetically modified mosquitoes reduce disease?

Some regions employ mosquito population control measures such as eliminating mosquito breeding sites, using larvicides to kill mosquito eggs, and employing adulticides to reduce the adult mosquito population. In certain areas, genetically modified mosquitoes have been used with approval from the Environmental Protection Agency (EPA). These modified mosquitoes possess a gene that prevents female mosquitoes from reaching adulthood, thereby reducing their ability to reproduce and lowering the mosquito population. Dr. Adalja considers genetically modified mosquitoes an essential tool in this context, and the EPA has determined that their use poses no risks to people, animals, or the environment.

References: https://abcnews.go.com/Health/genetically-modified-mosquitoes-vaccines-dengue-fever/story?id=103511659