Ashley Laird
Parasites and Pestilence
Human Biology 103
Spring, 2001
D. Scott Smith, MD, instructor

Homo sapiens beware . . .your zoonotic friends are not the only ones in danger of . . .


Adult worm of Dirofilaria immitis extracted from the heart and pulmonary artery of a dog.


    Dirofilariasis is derived from the Latin words diro and filum, meaning "evil thread."  In humans, it is the result of accidental zoonotic infection, with the distribution of infection in humans roughly paralleling the distribution of infection in animal hosts.  Dogs, cats, foxes, and other mammals are the natural hosts of Dirofilaria species, mosquitoes are the vector-intermediate hosts, and humans are the dead-end hosts.  Given that man is a dead-end host, worms rarely reach maturity in humans, and microfilaremia is not seen.  Dirofilariasis infection in dogs and cats can produce a potentially fatal heart condition called heartworm.  In humans, however, dirofilariasis infection is generally benign and asymptomatic.

History of Discovery
Clinical Presentation in Humans
Transmission and Life Cycle
Incubation Period
Diagnostic Tests
Management and Therapy
Public Health and Prevention Strategies

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Website constructed on May 14, 2001
Last modified on May 24, 2001