Heartworm Flashcards
what is the science name for heartworm
Dirofilaria immitis
what is the primary host of heartworm
dogs
true or false:
heartworm is the most important parasite in dogs
true
true or false:
prevalence of heartworm parallels that in dogs in the same area
true
true or false:
all ages are equally as susceptible
true
what is the needed to complete the life cycle of Dirofilaria immitis
mosquitos
where do adult heartworms live
pulmonary artery
what part of the heartworm life cycle circulates in the blood
microfilariae
what is the infective stage of the heartworm life cycle
L3
where do the microfilaria become L3
in mosquitos
where does the L3 larvae of the heartworm mature to adults
dog host
how long is normal development from L1 to L3 in the mosquito
10-14 days (2 weeks)
how many days after infection with L3 are there adult worms in the pulmonary vessels
70 days post infection
when can vascular damage from heartworm begin after infection
70 days - adult worms make their way to the pulmonary artery
how long does it take for to heartworms fully develop into an adult
about 6 months
when can heartworm start producing microfilaria
at fully maturity (6 months)
true or false:
in cats, although the life cycle is the same it takes longer to complete
true
true or false:
dogs are more likely to have aberrant migration of worms to ectopic sites
false
cats
how many worms are needed to cause life-threatening disease in cats
few worms
<5 worms
why is diagnosis of heartworm difficult in cats
fewer worms
only females can be detected
theres a risk of having only 1-2 worms and both could be males
this would result in 0 detection
true or false:
cats will have a prominence of microfilaria at times of exams
false
<5% of cats are MF+ at time of exam
this is because cats are likely to become infected from other HW+ dogs and not cats
what are the main organs involved in heartworm cases
heart
lungs
what determines the severity of HW disease
number of adult worms
duration of infection
individual host response
what is the impact on the heart / pulmonary vessels from HW disease
pulmonary arterial disease
what is the pathology of pulmonary arterial disease
inflammation (endarteritis)
villous thickening of tunica intima
(1-3 months after worms arrive to heart)
what would the heart look like during a pathologic post-mortem exam
roughened, stippled appearance of pulmonary artery
what are the complications from pulmonary aterialitis
thickening of vessels
loss of vessel elasticity
increased pressure
what is the bacterial endosymbiont found in many filarial worms and insects
wolbachia
what is the importance of wolbachia to the worms
perform beneficial functions for the worms
how does Wolbachia impact pulmonary arterialitis and inflammation
induced innate inflammatory response by macrophages and neutrophils
what are the 3 stages to feline HWD
- worms reach blood vessels of the lung
- degenerating worms induce pulmonary inflammation and thromboembolism
- chronic respiratory disease
what is the effect the worms have on the pulmonary artery at arrival
acute inflammatory response
what part of heartworm disease is caused by immature worms and important in cats
HARD
heartworm-associated respiratory disease
what is caused by large numbers of worms in the tricuspid valve and causes hemoglubinuria in dogs
caval syndrome
true or false:
caval syndrome is treatable in dogs
false
what is the TOC for caval syndrome is wanted
surgical removal of worms via jugular vein
how is caval syndrome different from typical pulmonary aterialitis in dogs
worms are backed up through the tricuspid valve
what are the clinical signs for mild to moderate heartworm disease in dogs
chronic cough
dyspnea
decreased exercise tolerance
what are the clinical signs of moderate to severe heartworm disease in dogs
syncope
hemoptysis
what is the clinical sign for severe heartworm disease in a dog
congestive heart failure
what are some clinical signs associated with chronic cases of heartworm disease in a cat
coughing, dyspnea
vomiting unrelated to eating
lethargy, anorexia, weight loss
systolic heart murmur
what is the most important thing to do before initiating a treatment regimen
determining what class of disease is present
what are the common signs seen on a physical exam of a cat for heartworm
often transient and non-specific
mainly respiratory, gastrointestinal and occasionally neurologic
what is used in the adult heartworm antigen kits to detect worms
female uterine antigen
when can the antigen test start to detect worms at the earliest
5 months
when would you for sure see a + for a + case of heartworm
7 months
