Which group of diseases has birds as reservoirs and can be transmitted by multiple mosquito species?

• A. Malaria
• B. Dog Heartworm
• C. Encephalitis Viruses (EEE, WNV, SLE, CE)
• D. Dengue

Answer: (C)

Birds acting as reservoir hosts are a hallmark of encephalitis viruses such as Eastern Equine Encephalitis, West Nile virus, St. Louis Encephalitis, and California encephalitis group. In these viruses, wild birds keep the virus circulating in nature, and many different mosquito species can pick up the virus from infected birds and then transmit it to other birds or to mammals, including humans. That combination—birds as reservoirs and transmission by multiple mosquito species—fits this group best.

Malaria involves a protozoan transmitted by Anopheles mosquitoes, but the reservoir is primarily humans (and some other primates), not birds. Dog heartworm uses dogs as the main reservoir and is transmitted by mosquitoes too, but again birds aren’t involved. Dengue is mainly spread among humans by Aedes mosquitoes, with birds not serving as reservoirs.