SUMMARY: Morris Animal Foundation-funded researchers at the University of Pennsylvania are investigating how infection by certain bacteria decreases the ability of mosquitoes to transmit infectious larvae of Dirofilaria immitis, the agent of heartworm disease.
THE PROBLEM: Mosquitoes are required for heartworm transmission between dogs. Every year, more than 150,000 cases of canine heartworm disease are reported in the United States alone. Monthly preventive treatments for dogs have been widely available since the mid-1980s. However, drug-resistant strains are on the rise, highlighting the need for novel disease control strategies. The team hopes findings will provide a new approach to block the spread of the heartworm disease by targeting parasites in their mosquito host.
THE PROJECT: It’s been known for several years that certain types of bacteria live in mosquitos, and that
these bacteria influence the mosquitos’ biological processes. In this project, the research team is building
on preliminary data that showed that a certain type of bacteria, Wolbachia, blocked the development of
transmission stage of D. immitis, the heartworm parasite. In this project, the team expanded on this exciting
finding.
PROJECT FINDINGS: The major findings from this study include:
• Dirofilaria immitis secretes proteins into the mosquito that may have immunomodulatory functions. This is an exciting and novel finding that arose serendipitously from experiments supported by this work.
• Using a natural, major vector responsible for heartworm transmission, the mosquito Aedes albopictus, the team found that colonization by the bacteria Wolbachia, results in a decrease in mosquito transmission potential.
Unfortunately, the team was unable to complete some of the work due to difficulties in sourcing Wolbachia. However, the team had multiple publications arising from the study, several veterinary and PhD students worked with the team, including two Morris Animal Foundation Veterinary Student Scholars.
In addition, Dr. Povelones was an invited speaker at several international meetings and presented findings
from the study.
POTENTIAL IMPACT: The findings from this study has provided important groundwork for transitioning this technology to field populations of mosquitoes. The team hopes this technology could also be leveraged to inform strategies to combat other important mosquito-transmitted human diseases, including malaria and dengue fever.