ST. JOSEPH, Trinidad — Neglected Tropical Diseases (NTDs) have historically received less attention than other diseases, yet they disproportionately afflict the world’s impoverished. Mosquito-borne diseases like dengue fever, Zika and chikungunya are classified as NTDs despite the fact that 700 million people in both developing and developed countries contract them each year.
Mosquito-borne diseases suck billions of dollars from developing economies, inherently impeding their development and simultaneously perpetuating the incidence of disease. The living conditions of low-income communities catalyze a cycle in which the poor are disproportionately affected by mosquito populations. Additionally, the unequal resource allocation to treat these diseases contributes to keeping the affected populations in those very conditions.
Mosquito-Borne Diseases in Low-Income Communities
Low-income communities tend to harbor mosquito breeding grounds due to poor waste management systems. Disease ecology associate scientist Shannon LaDeau conducted research that highlighted low-income communities like Baltimore, Maryland. These communities suffer from large amounts of improperly discarded trash and furniture. Items like tires, toilets and flower pots foster mosquito reproduction when they collect undisturbed rainwater.
Areas where these objects are disposed also tend to be surrounded by overgrown vegetation, providing an ample supply of algae and other detritus for mosquito larvae to feed on and grow. Generation after generation of mosquitoes can complete their life cycles in these little pockets of water.
This same trash provides a food source that encourages rodents to congregate in low-income communities. Pest control is poor in these neighborhoods, allowing opportunistic mosquitoes to feed on humans, the livestock, which tends to be raised nearer poor neighborhoods, and the multitude of rodents. Since mosquitoes have only about one to three-mile flight range, they will proliferate in these low-income areas where food sources are abundant. In fact, researchers found there were three times as many biting mosquitoes in poor Baltimore towns than wealthier areas.
Overcrowding and Poverty
In this vein, the more densely populated an area, the more susceptible it is to facing a mosquito-borne disease epidemic. Many low-income communities suffer from overcrowding, a prime environment for mosquito populations to thrive and spread mosquito-borne diseases. Mosquitoes spread diseases when they bite an infected person, become a carrier of the disease, then bite more people. This transfers the disease directly into the new hosts’ blood. The Aedes albopictus species in particular only travels a maximum distance of 300 feet to feed. They are prime candidates to spread dengue, chikungunya, yellow fever and Zika to everyone in a densely packed environment.
In addition, the economic disparity between investments in mosquito control measures in low-income vs. high-income neighborhoods accounts for large populations of mosquitoes plaguing the impoverished as well. Additionally, if mosquito treatment is available at all, the cost is often just not feasible for low-income families.
Lastly, access to healthcare tends to be poor in low-income communities. If cost is too high, medical facilities are overwhelmed or just located too far away, infected persons may be unable to receive treatment. Lack of access to medications and other treatments at these facilities contributes to the one million yearly deaths by mosquito-borne diseases.
The Danger of NTDs
The high incidence of mosquito-borne diseases in low-income communities affects everyone. Florida already experienced a Zika outbreak in 2016 when infected mosquitoes spread due to human travel. Los Angeles is the most mosquito-infested city in the U.S. due to the continued spread of the Aedes mosquito. This species is believed to have settled in California in 2013 after arriving aboard a cargo ship.
Since mosquitoes thrive in warmth, the warming effects of climate change could amplify the threat of mosquitoes in areas where they were previously of low concern. Currently, cold areas may see the spread and enhanced survival of mosquitoes, which bring with them diseases that cause bleeding, organ impairment, birth defects, brain disorders and death. Without more attention to this matter, this distant epidemic could become another pandemic. Luckily, organizations are working on mosquito control programs to decrease the incidence of mosquito-borne diseases in low-income neighborhoods.
Fighting Mosquito-Borne Diseases in Low-Income Communities
The CDC mentions the Sterile Insect Technique, which is a form of insect birth control. Large numbers of sterile male mosquitoes are created in a lab and released to mate with females in the wild. Females who mate with these sterile males will not produce offspring, thus decreasing the mosquito population in that area.
People will not experience an increase in mosquito bites in these areas since male mosquitoes feed on nectar. However, this method is effective only if sterile males “outnumber wild male mosquitos.” Additionally, labs would need to continuously produce and release sterile males since they cannot reproduce themselves.
The World Mosquito Program has found a self-sustaining method of controlling mosquito-borne diseases in low-income neighborhoods. The program breeds Aedes aegypti mosquitoes that carry a safe, naturally occurring bacteria called Wolbachia. It then releases them into consenting neighborhoods.
Wolbachia competes with viruses that cause dengue, Zika, chikungunya and yellow fever, hindering them from reproducing within the mosquito vector’s cells and decreasing the mosquito’s ability to transmit these diseases. The bacteria is passed down via eggs through mosquito generations, so the solution is long-term. The Wolbachia method has resulted in a significant 77% reduction in dengue incidence and an 86% reduction in dengue hospitalizations in a trial in Yogyakarta.
While science is making strides to lessen the threat of mosquito-borne diseases, governments must address living conditions in low-income communities before the world can conquer this danger. Mosquito-borne diseases in low-income communities pose a threat to us all. However, people can do simple things like picking up trash to avoid contributing to the problem.
– Serah-Marie Maharaj