Some of America’s leading infectious disease experts warn that yellow fever could make a return in the U.S., with the South at the highest risk.

In an editorial published in the New England Journal of Medicine, infectious disease experts Peter J. Hotez, M.D, Ph.D, and Angelle Desiree LaBeaud, M.D warn that clusters of cases recorded over summer are not an outlier, but instead a sign of things to come.

This summer saw a malaria outbreak in several states, like Arkansas, Florida, Maryland and Texas, as well as cases of dengue and West Nile virus . Yellow fever, a cousin of these diseases, may soon cause an epidemic in the United States for the first time in more than a century.

Mosquito-borne illnesses, scientifically called arboviruses, are becoming more common; the authors say that poverty in Texas and Gulf Coast states is a serious risk factor because of low-quality housing, inadequate window screens, and dumping of tires create a habitable environment for disease-spreading mosquitoes.

Yellow fever is most common in South America and Africa, where it causes 200,000 infections and 30,000 deaths every year, according to the World Health Organization. It fever a fever , nausea, and fatigue, but in more severe cases, it can cause yellowing of the skin and eye, severe bleeding, and organ failure, making it a possibly deadly disease.

When U.S. outbreaks were more common, it was infamous for causing “vomito negro”—black vomit from blood entering the gastrointestinal tract in the disease’s end stage. In the 1800s, the infection was given the nickname “yellow jack” because of the flags that ships would hoist while quarantining suspected cases of the disease.

The last time a yellow fever epidemic happened in America was in New Orleans in 1905. It sickened 5,000 people and killed 1,000.

The authors say cities such as Galveston, Corpus Christi and Houston in Texas, Mobile in Alabama; New Orleans in Louisiana, and Tampa in Florida are most at risk of a future outbreak.

“Such an epidemic could take a greater toll than most modern outbreaks of infectious disease in the United States,” the authors say.

The reasons for increased fears are threefold. First, the presence of dengue, malaria, and the West Nile virus indicates that the regions where they have been seen are becoming more habitable for disease-carrying mosquitoes.

Second, the increasing urbanization of areas in countries like Brazil is making it more likely that yellow fever will spill from jungle landscapes into urban areas, as an outbreak from 2016 to 2019 in the country showed that outbreaks can happen farther from forests than initially thought.

Third, El Niño, a weather pattern associated with warming surface waters that occurs around every two to seven years, may create yet more habitable environments for Aedes mosquitoes, bringing warmer and wetter conditions to already at-risk regions.

“With North America facing record-high temperatures and moisture and accelerated warming of its surrounding waters just ahead of an expected El Niño event, the United States could face similar conditions,” the authors predict.

There is a vaccine for yellow fever that provides lifelong protection; in 2021, Sanofi Pasteur announced that their yellow fever vaccine is available for purchase again in the U.S. However, the authors say this is still not enough, as the yellow fever vaccine is not included in routine vaccinations, and there is no national stockpile of yellow fever vaccines.

They warn that “During a sizable epidemic, yellow fever could tear quickly through unimmunized populations across the American South, and it is unlikely that the U.S. government would be prepared to acquire and distribute vaccines in a timely manner, even if there were public demand.”

They conclude that “yellow fever should be prioritized as part of our national pandemic-preparedness efforts, given that the conditions are now in place for yellow jack to return and sicken many people in southern U.S. cities.”

Malaria and dengue fever aren’t the only mosquito-borne illnesses to worry about

As a medical professional I can tell you we have many illnesses crossing our borders….just hang on! ~ Debbie Wright

Written by Sarah Braner for The Messenger ~ October 18, 2023