in dogs with D. immitis, the infective larvae migrate to the subcutaneous
tissues where they mature for several months. Once the nematode is
fully mature, it migrates to the right ventricle of the heart. After
six to seven months, the fully mature worm is able to produce microfilariae,
which enter the host dog's bloodstream (Shah).
in humans, worms are unable to reach maturity. In the case of subcutaneous
infection, if the infectious larvae is not immediately destroyed by
the human immune response to the the infection, it grows gradually and
reaches adulthood in about five months. The worm eventually becomes
constrained within an inflammatory nodule, where it survives for several
months or years and eventually dies and is destroyed (Pampiglione,
al). Since subcutaneous dirofilariasis infections generally
result in painless nodules that are asymptomatic, the infection may persist
for long incubation periods before an individual notices it and seeks medical
case of human pulmonary dirofilariasis, the infectious larvae migrate to
the veinous circulation, die in the right ventricle, embolize into the
pulmonary artery, and organize into a nectrotic and fibrotic nodule.
The shortest documented time between a negative chest x-ray and the appearance
of a pulmonary nodule is 5 months (Shah).
infections cause early intense irritation, which prompts early surgical
removal of the worm and thereby keeps the incubation period short.
to Main page