N1 - Heartworm Flashcards
causes heartworm disease
Dirofilaria immitis
- damage the heart and lung arteries, causing inflammation, scarring, and thickenig of lung tissue
- lead to high blood pressure in the lungs, forcing the heart to work harder
heartworm disease
life cycle pattern of Dirofilaria immitis
- microfilariae ingestion
- development in mosquito
- transmission to host
- maturation in host
- adult worm development
microfilariae ingestion
female mosquito takes a blood meal from an infected animal, ingesting microfilariae (L1 larvae)
development in mosquito
- ingested worms mature in stages (L1-L3) within 10-14 day if its warm (above 27C) or about a month if cooler (18C)
- only L3 stage can infect new host
transmission to host
- infectious L3 larvae move to mosquito’s mouthparts
- when mosquito bites a new host, they are deposited onto the skin and enter the wound
maturation in host
- L3 larvae develop into L4 larvae within 12 days then migrate through the body tissues
- they mature into young adults around 50-70 days and reach the heart and pulmonary arteries about 70-120 days after infection
adult worm development
- adult heartworms live in the heart and in the pulmonary arteries
- takes about 6-7 mon for worms to mature and produce offspring
- adult worms can ilve 5-7 years and even if adults die, microfilariae can survive for up to 2 years
mode of transmission
mosquito
pathogenesis of Dirofilaria immitis
- physical damage
- inflammatory response
- right-sided heart failure
- caval syndrome
- ectopic migration
physical damage of Dirofilaria immitis
- endothelial damage and inflammation
- increased pulmonary bp
- reduced blood flow to lungs
right-sided heart failure
right ventricular hypertropy
heartworm symptoms in dogs
- asymptomatic early on
- as it progress, cough, fatigue, difficulaty exercising
- severe cases cause breathing problems, weight loss, fluid buildup in abdomen, and heart failure
heartworm symptoms in cats
- coughing
- wheezing
- vomiting
- loss of appetite
- weight loss
- lethargy
- sudden death due to lung damage
heartworm symptoms in humans
- usually asymptomatic
- cough, chest pain, fever
- worms typically don’t mature into adults
diagnoses of heartworm
- serological test
- radiographs
- echoradiograph
- snap test
an ELISA for Dirofilaria immitis is an enzyme-linked immunosorbent assay that detects the presence of this parasite in a blood, serum, or plasma sample
serological test
Dirofilaria immitis usually diagnosed by finding of the distinctive coin lesions on chest x-rays
radiographs
heart ultrasound may help to assess the degree of heart enlargement, function, and even see if worms are present in the heart and associated blood vessels
echoradiograph
rapid blood test that detects the Dirofilaria immitis antigen in dogs and cats
snap test
distribution of Dirofilaria immitis
tropical, subtropical, and temperate regions of the world particulary humid areas
definitive mammalian hosts for Dirofilaria immitis
- domestic dogs
- wild canids
- raccoons
treatment of Dirofilaria immitis
- melarsomine
- doxycycline
- adulticide treatment
- worms are eliminated quickly and the progression of disease stops
melarsomine
