University of Iowa researchers have found that a vaccine used to prevent dogs from contracting the deadly, parasitic disease canine leishmaniasis also can be used to treat currently infected dogs, providing a new avenue of treatment for millions of infected dogs globally.
Canine leishmaniosis (CanL) is a major zoonotic disease found in more than 70 countries and has recently emerged in the United States. CanL also is a concern in countries where imported disease creates a veterinary and public health problem.
The study, recently published in the journal Vaccine, provided the first clinical trial of the LeishTec vaccine in infected dogs. The vaccine is commercially available in Brazil and is frequently prescribed by veterinarians there. The research was funded by Morris Animal Foundation.
“Usually vaccines prevent infections, but some, like the rabies post-exposure prophylactic vaccine, can be used after infection. We were happy to prove this was the case with LeishTec,” said Dr. Christine Petersen, University of Iowa associate professor of epidemiology, and the study’s lead author.
The team tested the vaccine in eight states on more than 400 dogs, almost all foxhounds, as they are one of the breeds mostly likely to carry the disease in North America. Researchers split the dogs into control and experimental groups, vaccinated the experimental groups three times in six weeks and then checked each dog every three months for the next year to determine the vaccine’s effectiveness. They discovered it was not only safe to give the vaccine to already infected dogs, but it also minimized disease in the experimental group.
Canine leishmaniasis is caused by the parasite Leishmania infantum and is typically transmitted by sand fly bites in tropical countries. It also can be spread through mothers to their pups. In the United States, it’s believed many foxhounds were born with CanL through breeding with imported hounds from endemic areas. Symptoms can range from skin sores and weight loss to blindness and kidney failure. Treatment is available, but most dogs die from the disease despite therapy.
[Photo: Dr. Christine Petersen]