Man’s Best Friend with a Risk: CDC Identifies Dogs as New Threat Might Transmit Flesh-Eating Parasite to Americans

The CDC has issued a warning that there is a potential for pet dogs to transmit a new, deadly flesh-eating parasite to humans in the United States.

A collaborative team of researchers from the University of Iowa, US Army Veterinary Services, Johns Hopkins University, and the CDC has expressed concerns that this disease could make the leap from dogs to insects and subsequently spread within the insect population.

The cause for alarm revolves around a parasitic disease called Leishmaniasis, typically transmitted by sand flies. Historically, cases were limited to individuals returning from regions where the disease is endemic, such as the Middle East, Asia, Africa, and Latin America.

However, recent findings indicate that Leishmaniasis is now being detected in people with no travel history to these countries, hinting at potential domestic transmission.

This development raises concerns about the possibility of the more severe variant of the disease, known as visceral leishmaniasis, spreading within the United States. While there are currently no confirmed cases, this deadlier form of the disease can be transmitted by dogs, which are increasingly being imported into the country.

The most common form of Leishmaniasis in the US, known as cutaneous leishmaniasis, results in skin infections characterized by oozing ulcers and open sores. In contrast, visceral leishmaniasis can lead to fever, weight loss, anemia, and enlargement of the liver and spleen. If left untreated, it can be fatal. Once the parasite is present in insects, it is transmitted through sandfly bites, following a similar pattern as cutaneous leishmaniasis.

Visceral leishmaniasis is caused by a related parasite known as leishmania infantum, which affects internal organs and is responsible for over 50,000 deaths annually in regions where it is prevalent, primarily in India, Bangladesh, Sudan, and Brazil. In the Americas, approximately 3,800 cases of visceral leishmaniasis are reported each year, with a mortality rate of roughly seven percent.

Initial symptoms often manifest as a small bump resulting from a sand fly bite, which then develops into ulcerous sores.

Dr. Mary Kamb, a medical epidemiologist working within the Centers for Disease Control and Prevention’s (CDC) Division of Parasitic Diseases and Malaria, shared insights with USA Today, stating, “This is a disease that we in the United States don’t really think about. It’s really a disease that belongs to other countries.”

Dr. Kamb and her research team have identified cases of leishmaniasis in numerous tissue samples collected from individuals who have not ventured outside the United States.

These patients have presented with skin infections caused by leishmaniasis, which typically originate as small bites from sand flies and subsequently develop into ulcerous sores over the course of days to weeks.

Dr. Kamb elaborated on the symptoms, saying, “People could be asymptomatic and not develop anything, but when people are symptomatic, they develop ulcers on their skin and sometimes it starts like a little tiny volcano with a crater in it.”

The location of these sores often corresponds to the site of the initial sand fly bite. Notably, the parasite responsible for leishmaniasis disrupts nerve function in the skin, resulting in generally painless sores. Nevertheless, they can leave lasting scars and be disfiguring, particularly when they occur on a person’s face.

The CDC study primarily examined skin samples from Texas, the sole U.S. state where healthcare providers are mandated to report cases of leishmaniasis. Additional cases have also been documented in southeastern Oklahoma, as detailed in a 2021 research review.

For the treatment of visceral leishmaniasis, healthcare professionals commonly employ an antifungal medication called liposomal amphotericin B. Notably, there is no available vaccine or preventive medication for humans, so individuals are advised to protect themselves from sand flies using methods such as nets and insecticide sprays.

However, it is worth mentioning that a vaccine is available for dogs. Additionally, collars infused with insecticides and spot-on treatments designed to prevent sand fly bites have proven effective in safeguarding against leishmaniasis in canines.

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