WSU receives grant to test new rabies control strategy

A Washington State University-led study funded by a $665,000 grant from the National Institutes of Health will test the effectiveness and feasibility of a new strategy to help control rabies in Africa.

The five-yearproject will explore whether supplementing traditional injectable vaccine campaigns with oral vaccines for free-roaming or hard-to-handle dogs can improve vaccination coverage and reduce both human and canine rabies cases in Tanzania, a country where the disease remains a major public threat.

"Injectable vaccinations will likely remain the most cost-effective option when you're reaching easy-to-handle dogs, but in many communities there are often dogs that remain unvaccinated because they are very time-consuming and dangerous to catch," said Ahmed Lugelo, a graduate student who is leading the study under the guidance of Dr. Felix Lankester, a professor in the WSU College of Veterinary Medicine's Paul G. Allen School for Global Health. "Our goal is to see if oral rabies vaccination can fill that gap, allowing vaccinators to reach these dogs quickly and safely. This could have a significant impact on the coverage achieved, meaning rabies transmission is stopped more quickly, at less cost and, most importantly, fewer people are bitten."

Rabies has the highest fatality rate of any known human infectious disease and kills around 60,000 people each year, nearly all occurring in Africa and Asia and caused by canine rabies. While human rabies can be prevented with post-exposure prophylaxis, the treatment is costly and often unavailable in remote communities.

Rabies has the highest fatality rate of any known human infectious disease and kills around 60,000 people each year, nearly all occurring in Africa and Asia and caused by canine rabies.

Traditional vaccination campaigns rely on injectable vaccines and on dog owners bringing their animals to vaccination points. In many rural areas, however, dogs go unvaccinated if they can't be restrained.

"The main problem with traditional rabies vaccination is that it depends on dog owners bringing their dogs to vaccination points, and that can often be difficult or even impossible," Lugelo said. "That means a lot of dogs get missed, so coverage never reaches the 70% threshold needed to stop transmission."

Oral rabies vaccination, which involves giving dogs edible baits containing the vaccine, could help cover that gap. While the approach is more expensive - with Lugelo estimating traditional injectable vaccines cost around $0.50 per dose, compared with $2 to $4 for oral baits - oral vaccination has been used successfully to eliminate rabies in wildlife populations across Europe and North America. Smaller studies in India, Thailand, and Haiti have also shown adding oral baits to routine injection campaigns can improve overall vaccination coverage in dogs, but the WSU study will be the largest of its kind.

The trial will be carried out in 36 wards across northern Tanzania. Each ward, made up of several villages, will be randomly assigned to either a group receiving only the injectable rabies vaccine or a group in which both injectable and oral vaccines are used, allowing researchers to compare vaccination coverage and to evaluate the cost and effectiveness of the combined approach.

Many rabies vaccines require refrigeration, which is a challenge in remote and resource-poor areas. During the trial, the researchers also hope to determine whether the oral vaccine remains potent following storage in locally made clay coolers, called Zeepots, which maintain temperatures below 77° C without electricity and would eliminate the need for refrigeration.

Using data from the trial, the researchers will model how increased coverage could reduce human dog-bite injuries and rabies cases. They will also conduct a cost-benefit analysis to determine whether combining injectable and oral vaccines provides a more sustainable and cost-effective approach for large-scale rabies control.

"Vaccinating those unreachable dogs will have real downstream benefits - preventing human exposures, reducing the need for expensive post-exposure treatment and limiting spillover into wildlife and livestock," Lugelo said. "In the long run, those benefits could far outweigh the extra cost per dose. Oral vaccination might not be the cheapest up front, but it has the potential to be the smartest investment."