Pregnancy and Mosquito-Borne Illnesses

Posted by Mosquito Squad
Pregnancy and Mosquito-Borne Illnesses

June 15, 2023

Mosquito bites are pesky, annoying, and itchy but can also be dangerous to human health. As vectors of numerous diseases, mosquitoes infected with viruses and parasites can pass on these disease agents to human hosts through their saliva when they bite and take a blood meal. Because of the severity of mosquito disease agents, mosquitoes pose a significant threat to the health of expectant mothers worldwide. This blog will highlight notable mosquito-borne illnesses and explain their vector, disease agent, method of transmission, and risk to both mothers and children alike.

West Nile Virus

Disease Agent: Virus

Vector: Culex species mosquitoes (learn more about different mosquitoes species here)

West Nile Virus (WNV) is a flavivirus found throughout North America, Africa, Europe, Asia, and the Middle East. Mosquitoes become infected with West Nile Virus when they take bloodmeals from birds carrying the disease. Birds are amplifier hosts, as the virus uses the birds' immune systems to multiply to high levels. The virus does not kill the birds. However, birds infected with WNV often exhibit signs of neurological distress. Humans are "dead-end hosts," meaning the virus does not amplify to high enough levels in our bloodstream to infect non-infected mosquitoes. If a non-infected mosquito bites a human with WNV, the mosquito will not pass on the virus.

Most infected individuals will not exhibit any symptoms. However, 1 in 150 people develop a severe illness that can lead to death. WNV can develop into West Nile Fever (WNF), an intense fever accompanied by additional symptoms (nausea, rash, myalgia, malaise). Pregnant women may develop the same symptoms as typical infected individuals, but pregnant women are at no higher risk of contracting WNV.

West Nile Virus is not contagious, nor is it an infectious disease. However, there is evidence that WNV can be spread from expectant mothers to their babies during pregnancy. The risk of transmission from mother to child during pregnancy is low but possible. According to a 2013 paper published in NCBI/National Library of Medicine, there are no significant birth defects or risks for "adverse infant outcomes."

There are no current vaccines to prevent infection or medications that can treat individuals infected with WNV. Pregnant women are advised to take the necessary precautions to lower their exposure to mosquito bites and their potential exposure to WNV. This includes wearing long clothing in prevalent mosquito areas and using EPA-registered insect repellents safe for pregnant and breastfeeding women.

Zika Virus

Disease Agent: Virus

Vector: Aedes species mosquitoes (learn more about different mosquitoes species here)

Zika Virus (Zika) is a flavivirus primarily found throughout South America, Sub-Saharan Africa, and South East Asia. In 2015 and 2016, Zika outbreaks were documented in the United States in Florida and Texas. Though Zika is not currently registered as a severe disease in the United States, the mosquito vectors Aedes aegypti and Aedes albopictus are found throughout the southern United States. Zika is primarily spread through infected mosquitoes, but unlike other arboviruses, Zika can also be spread through person-to-person contact during pregnancy and sexual transmission (the CDC also suspects blood transfusions could spread Zika from one individual to another).

Like WNV, many infected individuals will exhibit no symptoms or mild symptoms. The most common symptoms include developing a fever, rash, joint and muscle pain, and red eyes. These symptoms rarely escalate to severe levels, and infected individuals typically recover within several days. However, pregnant women infected with Zika are at high risk of having children with brain defects or having failed pregnancies altogether.

Zika infection during pregnancy can lead to birth and brain defects in babies. Microcephaly is the most common defect where the baby is born with smaller heads than expected. This size difference can severely affect the baby's brain size and development, and babies with severe microcephaly can experience life-altering/lifelong conditions such as seizures, developmental delays, intellectual disabilities, and issues with vision, hearing, and the ability to swallow. Microcephaly can be diagnosed during pregnancy or after birth, and there is no cure or medical standard for treating this condition.

There are no current vaccines to prevent infection nor medications that can treat individuals infected with Zika. Pregnant women are advised to avoid traveling to areas where Zika is prevalent. Additionally, safe sex and communication with your sexual partner are crucial if you develop Zika-like symptoms or travel to places where Zika is prevalent.


Disease Agent: Protozoan (Parasite)

Vector: Anopheles species mosquitoes (learn more about different mosquitoes species here)

Unlike other diseases mosquitoes spread, malaria is not a virus. The disease agent for malaria is a parasitic protozoan that looks almost like a microscopic worm. This parasite takes advantage of the human and mosquito life cycle to survive and reproduce, and there are no animal reservoirs for malaria. This means that malaria transmission comes exclusively from infected mosquitoes biting healthy people and healthy mosquitoes biting infected people.

Though malaria is not a contagious disease, there are significant transmission risks through blood transfusions and pregnancy. Malaria does not always present symptoms, but individuals with HIV/AIDS, compromised immune systems, children under five years old, and expecting mothers are at high risk of developing severe symptoms. Severe symptoms of malaria include extreme fatigue, difficulty breathing, convulsions, impaired consciousness, and irregular bleeding. In addition to severe symptoms, malaria contraction during pregnancy can impact the mother's and fetus's health. Premature delivery, low-birth weight, stunted fetal growth, and fetal loss are among the most dangerous outcomes of contracting malaria.

Prevention is an essential strategy to avoid malarial contraction during pregnancy. This includes avoiding travel to malaria-prevalent areas and using bed nets and long sleeves to avoid getting bitten. In some cases, intermittent preventive treatment of malaria during pregnancy (IPTp) may be recommended to expecting mothers. IPTp programs often include prescribing an antimalarial drug to reduce the impact of present and lower the risk for future malarial infections. This program is not a cure for malaria, but it has effectively reduced the adverse health risks experienced by mothers and children during pregnancy.

How Can Mosquito Squad Help?

Mosquito-borne illnesses pose significant health risks, especially to women undergoing pregnancy. While most mosquito-borne diseases are perceived as tropical or only found overseas, the increase in mosquito population and distribution throughout the United States makes it more and more likely to spread to the states. At Mosquito Squad, our mission is to protect your lawn and loved ones from the nuisance and danger of mosquitoes.

Contact your local Mosquito Squad today or call us at (810) 202-9771 to learn about our treatment options and schedule your service today.