Vaccine Holds Key to Canine Leishmaniasis Treatment

University of Iowa researchers have found that a vaccine used to prevent canine leishmaniasis (CanL) is also effective in treating the disease in infected dogs. CanL is a deadly zoonotic disease found in more than 70 countries, including the United States. While some forms of treatment are available, most affected dogs die from the disease despite therapy.

Caused by the parasite Leishmania infantum, CanL is typically transmitted by sand fly bites in tropical countries but can also be spread from mothers to their offspring. In the United States, experts believe the disease was introduced to foxhounds through breeding with dogs imported from endemic countries. The number of dogs in the United States diagnosed with CanL is unknown, but the disease affects about 20% of dogs in Southern Europe and is expanding northward. In Brazil, millions of infected dogs are euthanized every year to prevent spread of the disease to humans.

The group’s study—recently published in Vaccine and funded by Morris Animal Foundation—was the first clinical trial of the LeishTec vaccine in infected dogs. LeishTec is commercially available in Brazil and prescribed frequently by the country’s veterinarians.

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The team tested the vaccine on more than 400 dogs across 8 states. The investigators split the dogs—mostly foxhounds—into control and experimental groups. The experimental groups were vaccinated 3 times over a 6-week period and then rechecked every 3 months for the next year to determine the vaccine’s effectiveness. The investigators discovered that the vaccine safely minimized the disease in the experimental group.

“This is an important study that is going to make a big difference in canine health globally,” said Kelly Diehl, DVM, DACVIM (SAIM), interim vice president of scientific programs at Morris Animal Foundation. “We now have a new tool in the toolbox to control this disease and give countless dogs longer, healthier lives.”