Flashcards
Heartworm basics
Cards in this deck (18)
- 1DistributionNorth America (and parts of Canada)
- 2Prevalance (rate in endemic area, sex, age, breed, % in Alabama)In 40-60% of outdoor dogs in endemic areas.
Males infected 4x more
5x more common in outdoor dogs
Most infections between 3 and 15 years
More common in large breeds
3.73% in Alabama - 3Potential Hosts and habitatsCanids, felids, ferrets, sea lions, humans, others
Adult worms found in right ventricle, pulmonary arteries, sometimes in right atrium, vena cava, eye, skin, and central nervous system
Microfilariae in circulating blood - 4—Dirofilaria immitis
(long, slender, white)
Males are smaller and have a corkscrew tail
Females are about twice as big
Bigger than Dipetalonema reconditum - 5—Microfilariae
(tapered at anterior end, visible cellularity at head, tail straight or hooked)
More numerous in hosts that other filariids
May move in place
- 6What is microfilarial periodicity?It is the variation in the number of microfilariae that appear in circulation over time.
D. immitis microfilarial have nocturnal and incomplete periodicity, meaning more are present in the evening hours, but they never disappear completely.
Diurnal=daytime activity
Complete=complete disappearance for a certain amount of time - 7What is Heartworm Development Unitss (HDUs)?Every degree above 57 degrees (unlikely to develop below)
- 8Life Cycle in dogs1) Mosquito feeds on dog with circulating microfilariae
2)develop to infective larvae
3) Larvae deposited at skin surface when mosquito feeds
4) 2 molts on way to heart and lungs
5) Worms mature in heart or lungs, mate, and produce microfilariae - 9What is disease a result of?Primarily the presence of adult worms in the right ventricle and pulmonary arteries. Worms irritate the vessel walls and create inflammation (villous endarteritis). Fragments of dead worms (emboli) lodge in vessels.
- 10Clinical signsVillous endarteritis, right ventricular hypertrophy, exercise intolerance, liver and kidney disease, coughing, blood in sputum, condition lost, anemia, proteinuria
- 11Vena Cava Syndrome or Caval SyndromeWorms present in vena cava partially obstruct blood flow through tricuspid valve and interfere with valve closure. Results in severe congestion of the liver, heart murmur, sudden onset of severe lethargy and weakness followed by hemoglobinuria
- 12DiagnosticsHIstory/Clinical signs
Microfilariae in direct smear, modified Knott's test, and filter test
Antigen test
ECG
Rads, angiography, echo
CBC and Chemistry - 13What is antigen blocking, why is it an issue, and how can it be taken care of.It is when the D. immitis antigen is completely bound by anti-D. immitis antibodies, preventing it from binding to the capture antibody. This results in false negatives. It can be remedied with heat treatment or acid treatment.
Heat: 1 mL of plasma/serum in tube, place in a dry heat block for 10 minutes) centrifuge for 5 minutes, remove supernatant, use to perform test.
Acid: Treat with TCA followed by Tris buffer - 14TreatmentRemoval of adult worms (immiticide, 2.5 mg/kg)
Surgical extraction
Removal of microfilariae
Place of prevention (slow kill) - 15What is Wolbachia?Gram negative bacteria
Related to Ehrlichia and Anaplasma spp.
Endosymbiote
Located in hypodermis, ovaries, oocytes, and embryonic D. immitis
Important for biological and reproductive function of host
Can be treated with doxycycline or minocycline - 16Life cycle in cats1) L3 deposited by mosquitos
2)L3 molts to L4 in subcue tissue
3) L4 molts to L5 during migration to heart
4) Arrive in heart, carried to lungs. Most die, few mature. - 17What is HARD?Heartworm Associated Respiratory Disease in cats. Treat with symptomatic therapy and removal/slow kill.
- 18Acanthocheilonema reconditum Host Location Structure Life Cycle Treatment SignificanceFound in canids
In subcue tissue or abdominal cavity
Males .5 inch, females 1 inch
Microfilariae taken up by fleas or lice, mature to infective stage, deposited at feeding, words mature.
No treatment required
Can be confused with D. immitis
Information
- Description
- Brief overview of D. immitis infection in dogs and cats.
- Created by
- Cassie Bowling
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