Title: Deadly Tropical Disease Spreading in the US Raises Concern among Doctors
By Marc Lallanilla
Published Oct. 20, 2023, 11:36 a.m. ET
Doctors are warning about the emergence of a potentially lethal tropical disease in the US that was once considered rare. Leishmaniasis, a parasitic disease transmitted by tiny sand flies, is now endemic in the country. Previously, the disease was only seen in individuals who had traveled to tropical regions.
Dr. Gideon Wasserberg, a professor of disease ecology at the University of North Carolina, explained that most doctors were unaware of the presence of leishmaniasis in the US. The sand flies responsible for transmitting the disease are even smaller than mosquitoes, allowing them to pass through most window screens. They transmit the parasite by biting humans or animals.
Dr. Mary Kamb, a medical epidemiologist at the Centers for Disease Control and Prevention (CDC), revealed evidence at the American Society of Tropical Medicine and Hygiene’s annual meeting that leishmaniasis has been found in individuals who have not traveled outside the country. This discovery confirms that the disease has become a part of living in the US.
Experts suggest that the warming climate contributes to the expansion of sand flies’ territory, enabling them to spread diseases like leishmaniasis farther north. So far, leishmaniasis cases have been reported in Texas, possibly because other states do not require doctors to report the disease to public health officials. However, sand flies have been discovered as far north as New Jersey, Delaware, and Ohio.
Leishmaniasis is not the only tropical disease making its way further into the US. Malaria, for example, may now be endemic in states like Florida and Texas. Dr. Pedro Cecilio of the National Institutes of Health explained that if the average temperature continues to rise in northern states, sand flies will be able to establish themselves there and transmit the parasites.
Leishmaniasis has two main types: cutaneous and visceral. The cutaneous form affects the skin, while the visceral form affects internal organs and can cause up to 20,000 deaths annually. Symptoms of leishmaniasis include skin sores, bumps, lumps, and ulcers. With early detection, the disease can typically be treated with anti-parasitic medications, although healing can take several months or years, leaving scars.
Interestingly, dogs can also carry leishmaniasis and serve as a means of spreading the disease to other animals and humans. Approximately 1 million dogs are imported into the US, and some can be carriers of the parasite. While there is no human vaccine for leishmaniasis, vaccines for dogs are available in Europe and Brazil.
To prevent leishmaniasis transmission, the CDC advises individuals in regions with sand flies to avoid outdoor activities, particularly from dusk to dawn when the sand flies are most active. It is also important to minimize exposed skin and use insect repellents containing DEET on exposed skin areas.
As the US continues to face the presence of such tropical diseases, it is crucial for doctors and public health authorities to increase awareness and take necessary measures to prevent their spread.