Prepare for the Next Pandemic Threat, Mosquito-Transmitted Viruses and Parasitic Illnesses

This brief is part of “Election 2024: Policy Playbook,” a series by the Baker Institute and Rice University that offers nonpartisan, expert analysis and recommendations to equip policy leaders governing the United States and Texas in 2025.

The Big Picture

• Pandemic preparedness in America has historically emphasized our vulnerability to serious respiratory virus illnesses, such as avian influenza and coronavirus infections.
• Mosquito-transmitted virus infections and parasitic illnesses could present our next greatest challenge, which is especially true in the Southern U.S., where climate change and urbanization are accelerating.
• The emergence of mosquito-transmitted viruses and parasitic illnesses, such as malaria, would exert an enormous public health and socioeconomic toll, especially in the Southern U.S.
• Pandemic preparedness in the U.S. should implement modern biotechnology approaches for disease surveillance and prevention.

Summarizing the Issue

COVID-19 is still very much with us. Over this past summer, SARS-2 virus transmission reached extremely high levels. Fortunately, in the U.S., a new COVID-19 immunization tailored to the major circulating virus variants was made available by the end of August 2024, thereby reducing the risk of serious illness for the most vulnerable Americans.

However, we cannot be complacent about new virus threats. Established in August 2023, the White House “Office of Pandemic Preparedness and Response Policy” has been working overtime to manage a newly emerged H5N1 (avian influenza virus) on dairy farms in the Texas Panhandle. This virus has since spread throughout the Great Plains and elsewhere. In addition, a new group of organisms linked to Mpox (formerly known as monkeypox) is accelerating in central Africa and could come to the U.S. as a previous clade (referring to a cluster of viruses with a common ancestor that assists scientists with tracing related species) did in 2022.

However, mosquito-borne virus infections could pose an even bigger challenge to the health security of the U.S., in part because the health policy community seldom prioritizes these conditions compared to the big-ticket respiratory pathogens. As in previous summers, there were significant numbers of cases of severe neuroinvasive illness caused by West Nile virus, and even recently, Dr. Anthony Fauci required hospitalization for his West Nile infection. There were also several cases of severe neuroinvasive illness caused by eastern equine encephalitis.

Expert Analysis

These cases by themselves do not necessarily set off alarm bells. However, the worry is that they represent the beginning of a much larger mosquito-borne virus onslaught. This is because of what has been occurring in Brazil and the Caribbean in recent years, which has raised the prospect that something similar could happen in the Southern U.S.  The mosquito vector (an insect or other arthropod that spreads pathogens) Aedes aegypti — the most efficient transmitter of yellow fever, dengue, and Zika virus infections — also lives in the Southern U.S., which is a vulnerable region to several mosquito-transmitted viruses and parasitic illnesses.

The specific concerns for Texas and beyond are:

1. Yellow Fever: The most lethal mosquito-transmitted virus, yellow fever caused hundreds or even thousands of deaths in 19th-century epidemics in southern cities, such as New Orleans, Galveston, Huntsville, Vicksburg, and Memphis. In recent years, yellow fever has been mostly confined to the South American Amazon rainforest, but it has since expanded to more populated areas of southeastern or coastal Brazil, getting closer to that region’s megacities of Sao Paulo and Rio de Janeiro. The worry is that yellow fever could reemerge in the Caribbean or Southern U.S., where the yellow fever mosquito is also found. 
    
2. Dengue, Zika, and Oropouche: In June 2024, the Centers for Disease Control and Prevention (CDC) released a warning about the potential for dengue in the U.S. because of the record number of cases in Brazil and elsewhere in Latin America during the first half of 2024. Oropouche, transmitted both by mosquitoes and biting midges, has been expanding beyond the Amazon region, and transmission has been reported in Cuba for the first time. Both Oropouche and Zika infections in pregnancy have been linked to congenital birth defects or fetal deaths. In 2016, Zika cases appeared in both Texas and Florida. 
    
3. Malaria, Chagas disease, hookworm infection, and toxocariasis: Although these tropical infections are parasitic diseases, the transmission of each of these illnesses is now happening in multiple Southern states. Malaria is transmitted by mosquitoes (Anopheles) — with a small outbreak happening in Texas and Florida in 2023 — Chagas disease by kissing bugs (Triatomines), and hookworm and toxocariasis by worms or contaminated soil.

Policy Actions

• Recognize climate change, urbanization, and poverty as pandemic factors. Historically, most mosquito-transmitted and parasitic infections previously affected the Southern U.S., especially in the five Gulf Coast states — Texas, Louisiana, Mississippi, Alabama, and Florida — and Georgia. Now they may be reemerging, for reasons that are under investigation.  
  
  So far, climate change associated with warming temperatures and flooding is a major factor, as is urbanization due to the preferences of Aedes aegypti mosquitoes. Cities in Texas and neighboring Southern states are now some of the fastest-growing population centers in the U.S. Poverty, yet another factor, is associated with environmental degradation in low-income neighborhoods, where drainage ditches and discarded tires suitable for mosquitoes and other arthropod vectors are widespread. Yellow Fever would be especially catastrophic for this region.  
   
• Establish local, active disease surveillance. A major concern is how these diseases are often undetected due to a fragmented public health infrastructure and lack of active disease surveillance programs. There are differences in staffing and budgets across different counties and states in the region, which affect surveillance activities, as well as significant variation in the level of available vector control and virus detection expertise. In addition, molecular testing for both pathogens and their vectors needs to be expanded. 
  
  Along those lines, there is an opportunity to apply modern genomics (OMICS) approaches — such as wastewater/soil genomics and metagenomics. With regard to the former, it is now possible to identify new mosquito-borne viruses in wastewater testing, similar to wastewater testing conducted for detecting COVID-19 surges during the pandemic. Pathogen genomes, especially for parasites, can be detected in soil samples. For the metagenomics approach, the complete genome of collected mosquitoes or other vectors are sequenced, together with their viral pathogen genomes (viromes). This would reveal the presence of new vectors or their virus pathogens, an approach that was recently undertaken in China, but could be applied to vulnerable areas of the Southern U.S. 
  
  In collaboration with colleagues across several research centers at Baylor College of Medicine, I have suggested undertaking an ambitious county-by-county program to conduct such sophisticated OMICs studies – both wastewater/soil genomics and vector/virome metagenomics across the South or Gulf Coast region. This approach would create a more complete picture of the different pathogens and vectors in a given county, making it possible for physicians and other health care providers to refer to a detailed map of the potential disease-causing agents where they practice. This is a first step to creating a detailed surveillance map of new mosquito-borne and parasitic illnesses arising due to climate change and other factors. 
   
• Coordinate community outreach. In parallel, public policies would need to be established to determine how this information is appropriately conveyed to local communities, including both health care providers and community leaders. These practices would require coordination with local and state governments, as well as with the CDC and possibly other federal agencies.

The Bottom Line

Mosquito-borne viruses and parasitic illnesses are expected not only to become America’s new normal, especially in the Southern U.S., but also to carry a pandemic-level threat. Should this happen, it could exert an enormous public health and socioeconomic toll, especially on the Gulf Coast. Pandemic preparedness in the U.S. should prioritize these conditions and include an all-out effort to implement modern biotechnology approaches for disease surveillance and prevention. 

This material may be quoted or reproduced without prior permission, provided appropriate credit is given to the author and Rice University’s Baker Institute for Public Policy. The views expressed herein are those of the individual author(s), and do not necessarily represent the views of Rice University’s Baker Institute for Public Policy.