Parasitology Flashcards
What do lungworms in the airway rely on to move their eggs up to the pharynx?
Mucociliary escalator
What is the inflammatory response related to lungworms a reaction to?
The worms themselves and eggs
Will there be an increase or decrease in clinical signs after a treatment for lungworms?
Increase → inflammatory response to dead worms
What is the metastrongylid nematode parasite of cats in which the adult worms are found in the terminal bronchioles and alveolar ducts?
Aelurostrongylus abstrusus
What is the often intermediate host for order strongylida?
Invertebrate → mollusc
How are parasites of order strongylida diagnosed?
Finding larvae in feces
What type of inflammation do A. abstrusus eggs and worms stimulate that leads to nodule formation?
Granulomatous inflammation
What two conditions/diseases are resultant of the inflammatory response to A. abstrusus, presenting with clinical signs such as cough, increased breath sounds, tachypnea/dyspnea, nasal discharge, and/or sneezing?
Severe bronchitis and emphysema
What is the preferred test for identifying parasitic larvae?
Baermann test
Can A. abstrusus larvae be seen in a fecal floatation?
Yes
What lung patterns can be seen on radiograph of cats with A. abstrusus infections?
Bronchial or interstitial patterns
What is the treatment for A. abstrusus?
Macrocyclic lactones
Are the enoplida Eucoleus aerophilus nematodes bigger or smaller than A. abstrusus?
Bigger → 20-40mm, A. abstrusus → 10mm
How is E. aerophilus diagnosed?
Eggs in fecal floatation
What are the possible treatment options for E. aerophilus?
Macrocyclic lactones → moxidectin specifically or fenbendazole
What is the treatment for Cuterebra spp.?
Physical removal
Systemic disease in cats with Toxoplasma gondii infections is associated with what action of the parasite?
Tachyzoite multiplication in tissues
(T/F) Although Toxocara cati migrate through the lungs, it is very unlikely to see clinical signs.
True
What is the fluke parasite that is found in lung parenchyma of wild animals, dogs, and cats?
Paragonimus kellicotti
Is the above parasite (P. kellicotti) zoonotic?
Yes
How many intermediate (maybe paratenic hosts) do P. kellicotti have?
Two
(T/F) Adult P. kellicotti forms cysts in pairs in the lungs.
True
How is P. kellicotti diagnosed?
Eggs in sedimentation fecal exam
How is P. kellicotti treated?
Praziquantel or fenbendazole
What is the Eucoleus species that is similar to E. aerophilus but lives in the nasal passages and is more commonly found in dogs?
E. boehmi
Which macrocyclic lactone may be the most effective in treatment of E. boehmi?
Moxidectin
What is the canine nasal mite that is transmitted directly and is typically asymptomatic?
Pneumonyssoides caninum
What are the three genuses of lungworms, all of which are rare in the US?
Crenosoma, Filaroides, and Oslerus
How can Strongyloides spp. cause respiratory signs?
Larval migration in heavy infections
Respiratory disease is associated with what action of ascarid nematodes?
Larval migration through the lungs
After a pig is infected with Ascaris suum, how long does it take for the lung damage and consequent clinical signs to appear?
1-2 weeks
(T/F) A fecal float test will be diagnostic when clinical signs begin in swine infected with Ascaris suum.
F, prepatent period not complete
What life stage of Ascaris suum is very difficult to kill?
Egg
Is Ascaris suum zoonotic?
Yes
What husbandry style is related to swine lungworm (Metastrongylus) infections?
Backyard, pastured pigs
What is the recommended interval for deworming for Parascaris prophylactically?
Every 2 months
(T/F) Parascaris spp. Infections are common in young horses and respiratory disease from their larval migration is also common.
F, dz not common
Dirofilaria immitis are parasites of where in the body?
Pulmonary arteries
What size are female D. immitis worms?
30 cm
(T/F) The disease process of D. immitis involves their attachment and subsequent damage to the pulmonary arteries.
F, do not attach
What are the two definitive hosts of D. immitis?
Dogs and ferrets
What type of host are cats and other mammals for D. immitis?
Abnormal
What is the relationship between D. immitis and Wolbachia?
Symbiotic → Wolbachia is required for survival and reproduction of D. immitis
What is the prepatent period of D. immitis?
6 months
What is the infective stage of the D. immitis life cycle?
L3
How long can microfilaria circulate in peripheral blood?
1-2 years
What is the length of patency for D. immitis worms?
Up to 8 years
What group of drugs are used in treatment for D. immitis?
Macrocyclic lactones
(T/F) Macrocyclic lactones kill D. immitis L4 larvae when administered at any point in the life cycle.
F, only prior to 60 days
What life stage of D. immitis can you not unalive?
Juvenile/immature adults
What three things does the degree of damage due to D. immitis infection depend on?
Worm numbers, duration of infection, and host immune response
What lifestyle characteristic plays an important role in pathogenesis of D. immitis infections?
Exercise
Is villous proliferation pathognomonic for D. immitis infections?
Yes
What leads to tricuspid/right AV valve insufficiency related to D. immitis infections?
Increased arterial pressure
How long can microfilaria circulate in peripheral blood?
1-2 year
What occurs reflexively to the dilation of the right ventricle from the increased pressure and subsequent decreased cardiac output in D. immitis infections?
Compensatory hypertrophy
What syndrome is the most severe manifestation of heartworm disease?
Caval syndrome
What number of worms needs to be involved to induce caval syndrome?
40
How is caval syndrome treated?
Surgical removal
(T/F) Treatment and subsequent death of D. immitis worms tends to worsen the vascular damage being caused and enhance abnormal coagulation.
True
The release of what (in relation to D. immitis infections) is associated with the increase of proinflammatory cytokines and a decrease of the host’s immune response?
Wolbachia
Treatment of heartworm positive dogs with what drug prior to treatment with immiticide will decrease the pathologic changes associated with Wolbachia release?
Doxycycline
(T/F) D. immitis microfilariae are generally not pathogenic.
True
Of the diagnostic tests for D. immitis (MF detective, antigen detection, and antibody detection), which is used in cats only?
Antibody
If a dog has adult worms but not circulating microfilaria, what type of infection is this?
Occult/hidden infection
Though you can see microfilaria on a direct smear, what is the best diagnostic test for microfilaria detection?
Knott’s test
Are false positives possible for heartworm disease?
Yes, non-pathogenic worm present in US that produces MF
The antigen that is detected in D. immitis antigen tests is found in the highest amounts where?
Adult female worm reproductive tract
When is annual D. immitis antigen testing especially indicated for dogs?
When preventatives are not used year round
Dogs should not be tested for heartworm prior to what age?
6 months of age
(T/F) ‘Heartworm preventive’ prevents heartworm infection.
False
What drug class are the FDA approved heartworm preventatives that prevent development of adult worms that cause disease?
Macrocyclic lactones
(T/F) Although macrocyclic lactones may kill microfilaria, they are only FDA approved to kill L3 and L4 stages up to 6-8 weeks post infection
True
What is the duration of administration for doxycycline in the heartworm treatment protocol?
Day 1 - 28
What should be done on day 30 in the process of heartworm treatment?
Administer heartworm preventative; apply mosquito repellent
How long should you wait after your heartworm positive patient finishes their doxycycline course to administer the first melarsomine treatment?
1 month, day 61
When is the second melarsomine treatment done?
1 month after the first treatment; day 90
When is the third melarsomine treatment done?
1 day after the second treatment; day 91
When should a knott’s test be performed after the third melarsomine treatment?
1 month; day 120
What should be done if the above knott’s test is positive?
(When should a knott’s test be performed after the third melarsomine treatment? (1 month; day 120) )
Treat with microfilaricide and retest in 4 weeks
When should an antigen test be performed after the third melarsomine treatment?
9 months; day 365
What should be done if the above antigen test is positive?
When should an antigen test be performed after the third melarsomine treatment? (9 months; day 365)
Retreat with doxycycline followed by two doses of melarsomine 24 hours apart
What is the protocol for the not FDA approved non-arsenical adulticide treatment?
Doxy for 4 week period, monthly oral ivermectin until no appreciable disease on testing, antigen and MF testing every 6 months
(T/F) Exercise restriction is only applicable to arsenical heartworm treatment.
F, all hw treatments
Why are cats considered abnormal hosts for D. immitis?
Do not effectively support transmission
How do D. immitis infection related clinical signs differ in cats compared to dogs?
Cats - respiratory signs; dogs - circulatory signs
(T/F) Knott’s tests are used in the diagnosis of heartworm in cats.
F, cats rarely have MF
(T/F) Macrocyclic lactones are used as preventative in cats just as in dogs.
True