Human trials planned for vaccines against leishmaniasis skin disease

Ben Latham
Mon, 11 Sep 2023 23:35:56 +0000
Campus, Instagram Page, News, CRISPR, cutaneous, debilitating, disease, distinct, effective, gene, infection, L. major, L. mexicana, leishmaniasis, metabolic, mucocutaneous, Parasite, sand flies, Skin, technology, trials, vaccines, visceral

Ohio State will begin human trials for vaccines on for leishmaniasis, a parasitic skin disease, next year. Photo credit: Kateryna Kon

On Aug. 29, the Ohio State research team announced it reached human trials for two vaccines against a tropical, often neglected, parasitic skin disease after they were found successful in animals.

Leishmaniasis, which is endemic in 99 mostly developing countries, is transmitted through the bites of female sand flies, and no approved human vaccines currently exist. Bradford McGwire, parasitologist and professor of internal medicine at Ohio State, said the treatments used now to combat the near 1 million cases of leishmaniasis per year are antiquated and less effective compared to the vaccines being studied.

“There’s a need for development of newer kinds of less toxic anti-leishmaniasis to treat these diseases,” McGwire said. “The keys are identification and diagnosis of the infection, and then development of a treatment plan for these infections.”

Abhay Satoskar, co-leader of the research team and professor of pathology in the College of Medicine, said he is hopeful for phase one human trials to begin in the U.S. next year. The plan is for the vaccines to be given emergency authorization after two phases of trials have concluded.

According to two new papers published in iScience, the vaccines differ in how they produce metabolic changes in the body. The end result, however, is the same.

Satoskar said the two vaccines target different species of the disease — L. major and L. mexicana. The scientists used CRISPR — a technology that allows for selectively modifying DNA — to delete the gene from the species and remove what was causing the harmful effects of the disease in humans.?

With this, Satoskar said gene removal still allows people to develop immunity to the infection and provides protection against both the Old World and New World species.

McGwire said the disease comes in three main forms. Cutaneous leishmaniasis is the most common form, which causes ulcers on the skin a few weeks or months after a sandfly bite. Visceral and mucocutaneous forms are more debilitating and can be fatal if left untreated.

According to the World Health Organization, the visceral form is sometimes accompanied by no symptoms but affects the internal organs, while mucocutaneous destroys mucus membranes in the nose, mouth and throat.

“They’re found mainly in rural areas and various Third World countries,” McGwire said. “Although, there’s an increasing incidence of leishmaniasis primary infections that are happening in the United States.”