Download Dirofilaria immitis

Dirofilaria immitis
Christina Drazan

Taxonomy
 D. repens
 Subcutaneous in dogs
 In humans  manifests as either a wandering worm in
the subcutaneous tissue or granulomatous nodule
 D. tenuis
 Subcutaneous in raccoons
 In humans  wondering worm
 D. ursi
 Subcutaneous in bears
 Again in humans  wondering worm
Hosts
 Definitive host: dogs
 Accidental hosts: foxes, wolves, coyotes, cats,
ferrets, sea lions
 Intermediate host: over 70 species of mosquitoes
Geographic Distribution
Morphology
 Adults are long, white,
thread-like worms


Females are 25 to 30 cm
long
Males 12 to 16 cm long
with spirally coiled tail
Life Cycle
Life Cycle
 http://www.heartwormsociety.org/pet-owner-
resources/canine.html
Pathogenesis

Inflammation and thickening of the heart

Insufficient respiration, Chronic cough, Vomiting

It can be fatal

Symptoms appear when more than 25 worms are
present

≤60 worms causes circulatory problems

≥100 worms, there is blockage of the pulmonary
artery and right side of the heart, accompanied by
interference with the actions of the heart valves



Right side become dilated and enlarged
Blood backs up in the liver and other parts of the
body
Rarely survive
Diagnosis

Accurate patient history

Recognition of varied clinical signs

X-ray

Angiography

Ultrasound

ELISA testing for antigens secreted by female worms

Microfilarial detection and differentiation in blood smears

Necropsy examination
Treatment
 Adulticide
 Milarsomine dihydrochloride
 Thiacetarsemide
 Microfilaricide
 Milbemycin oxime
 Are toxic so careful observation is required after
administration
 Aren’t used until side effects from the adulticide are
fully gone
Public Health Concerns
 It can infect humans
 Subcutaneous nodules or in the lungs
 Commonly labeled as malignant tumors which
require invasive investigation and surgery before
being correctly diagnosed
Control
 Prevention
 Topical
 Oral