Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Parasitology > Non-GI Nematodes > Flashcards

Non-GI Nematodes Flashcards

1
Q

Where do non GI nematodes live?

A
  • heart
  • lungs
  • urinary tract
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which species get Dirofilaria immitis?

A
  • DOGS
  • rarely CATS (rarely patent)
  • v rarely PEOPLE (not patent; sub q & lung nodules)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how do we identify adult Dirofilaria immitis?

A
  • identification of adult parasites is usually based primarily on their location w/in host
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how do we identify microfilariae Dirofilaria immitis?

A
  • tapered anterior end & long, thin, pointed tail
  • can be distinguished from microfilaria of skin dwelling nematode Dipetalonema reconditum, which have a blunt head
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How do you distinguish Dirofilaria immitis from Dipetalonema (or Acanthocheilonema) reconditum?

A

“5 Rs of Reconditum”
- Round head
- rare
- reduced size & #
- recurved tail
- rapid movement
Reconditum is non-pathogenic & the adults live in sub q tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the life cycle of Dirofilaria immitis?

A
  • in Ca DH, adults are located in the pulmonary artery & R ventricle
  • microfilariae (L1) are released into the blood
  • following ingestion by a suitable female mosquito during blood-feeding, microfilariae undergo 2 moults to become infective L3 which move to mouthparts of mosquito
  • under ideal conditions (constant 27 C), approx 14 days are required for dev of infective larvae in mosquitoes
  • @ constant 18 C, larvae require approximately 1 month to become infective
  • during subsequent blood meal, infective L3 escape from mouthparts & penetrate skin of Ca, often through wound made by mosquito’s probiscis
  • in Ca, newly introduced larvae migrate in sub q CT
  • by ~ 3-4 m after infection immature adults are present in heart & pulmonary artery
  • PPP in Ca is 6-7 months
  • adult parasites can survive for 5-7 yrs
  • microfilariae can survive in Ca for up to 2 yrs in absence of adult heartworm
  • in Fe, it rarely completes dev to adult stage
  • infection is usually not patent
  • immature parasites may be present in heart & pulmonary arteries, but they are also common in other sites
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Pathogenesis & clinical signs of heartworm:

A
  • often asymptomatic
  • decreased exercise tolerance, coughing, anorexia, weight loss
  • severe cases: R sided heart failure, hepatic congestion, ascites, syncope, death
  • parasite Ag/Ab complex deposition can cause glomerulonephritis & proteinuria
  • caval syndrome (sm dogs, rarely cats): worms block caudal vena cava/tricuspid valve (requires immediate surgical removal of worms)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How is Dirofilaria immitis diagnosed?

A
  • Hx (geographic location, travel)
  • clinical signs
  • radiographs/ultrasound (enlarged pulmonary arteries & R heart; may see worms, check for caval syndrome)
  • diagnostic tests (microfilarial concentration test (modified Knotts); immunodiagnosis (adult female Ag detection (DOGS) & Ab detection (CATS)) - AHS recommends to do both dog tests annually
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the testing recommendations for heartworm? (questions)

A
  • who? pets living in or travelling from endemic regions
  • what test(s)? Ag, Knotts, or Ab (Fe)
  • where? annually in endemic areas
  • when? @ least 6 months after last possible exposure (spring in Canada)
  • why test? (prior to starting preventatives (anaphylaxis, masking); if suspect non-compliance in endemic regions; to monitor success of treatment; many drug companies will not cover cost of adulticidal treatments if pets are not tested annually)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

why would a dog who is positive on Ag test be negative on Knotts test for microfilaria?

A
  • could be false positive
  • could have tested too early in day (microfilariae are out in blood when they are most likely to be sucked up by a mosquito)
  • if you only have females (so no microfilariae)
  • only adults present
  • on monthly preventatives that can kill off microfilaria but not adults
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Why would a dog who was negative on an antigen test have microfilaria in buffy coat of PCV tube?

A
  • could be blocked Ag (Ag-Ab complex)
  • adults all dead but microfilaria still present (tail end of infection)
  • could be a different microfilaria
  • could have treated & killed adult heartworms but not microfilaria (2 different treatments)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do you interpret heart worm tests?

A
  • false positives on antigen test are possible, esp. in low prevalence regions like Western Canada (if suspect false positive, try a different test, then retest in 3 months if still not convinced)
  • false negatives on antigen & microfilaria tests (recent infections - immature females, PPP; single sex infections)
  • false negatives on Ag test (blocked Ag; Ag/Ab complexes)
  • false negatives on microfilaria tests (senescent infections - L1 may disappear after 9 months; Ca on monthly preventatives - masking; diurnal patterns in microfilarial activity in blood)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are monthly preventatives for L3 & L4 heartworm larvae?

A
  • ivermectin
  • milbemectin
  • selamectin
  • moxidectin
    resistance is developing to these
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the adulticide for heartworm?

A
  • melarsomine (immiticide)
  • NOT IN FE (toxic, need to be removed surgically)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the microfilaricides for L1 heartworm larvae?

A
  • ivermectin
  • moxidectin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What antibiotic is used to kill Wollbachia & why?

A

Doxycycline
- kills gut bacteria inside of heartworm, starving them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

In cases where adulticide treatment is not possible, what might be considered a salvage procedure?

A
  • use of monthly oral ivermectin or topical moxidectin heartworm preventative along w/ doxycycline
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how do you treat for heartworm?

A
  • PREVENTATIVES: START ONE MONTH FOLLOWING THE FIRST POSSIBILITY OF EXPOSURE & CONTINUE UNTIL ONE MONTH AFTER THE LAST POSSIBILITY OF EXPOSURE (MAY-OCT IN CANADA)
  • in Ca that are confirmed positives: if symptomatic stabilize w/ glucocorticoids, diuretics, vasodilators, fluids, oxygen; treat infection w/ macrocyclic lactones, doxycycline, melarsomine, prednisone, & cage rest
  • risk of pulmonary thromboembolism depends on activity level of dog, & intensity & extent of disease
19
Q

What is the ecology/epidemiology of heartworm?

A
  • domestic & wild canids normal DH
  • mosquito vectors (culicidae): Aedes spp, Anopheles spp., Culex spp
  • endo-symbiotic bact Wolbachia
  • seasonal transmission
  • patchy geographic distribution
  • low test positivity in Ca in Canada
20
Q

Public health significance of Dirofilaria immitis?

A
  • human inf has been reported from many of countries in which parasite occurs in Ca (including USA, but only 1 case has been reported in Canada (in Ontario, in a woman who had recently traveled in several areas outside Canada that are endemic))
  • usually parasite doesn’t complete its dev in people, & causes a sm “coin” lesion in lung, which may be symptomatic
21
Q

Where is Angiostrongylus vasorum found?

A
  • Dogs, wild canids, & mustelids
  • In Canada: Newfoundland & NS
  • transmitted by gastropod intermediate hosts
22
Q

Life cycle of Angiostrongylus vasorum?

A
  • like most metastrongyloid nematodes, it undergoes indirect life cycle w/ gastropod IH
  • adult parasites live in the R ventricle & pulmonary arteries of DH (canid)
  • they produce eggs which dev into L1 which are coughed up, swallowed, & passed in feces of canid DH
  • L1 from feces enter gastropod IH where they dev into L3
  • canid DH become infected when they consume gastropod containing infective L3 or L# that have emerged spontaneously from gastropods
  • frogs & Av may serve as paratenic hosts, but their role in transmission is not clear
  • PPP from ingestion of L3 to production of L1 in feces is 6-8 wks
23
Q

Public health significance of Angiostrongylus vasorum?

A
  • not known to be zoonotic
  • other spp of genus are zoonotic, but are not found in Canada
24
Q

How is Angiostrongylus vasorum diagnosed?

A
  • clinical signs similar to Dirofilaria immitis
  • can be more severe: disseminated intravascular coagulation; rarely CNS
  • L1 detected on Baermann or in bronchoalveolar lavage (BAL)
  • ELISA for Ag of adult nematode (Europe)
25
Q

how is Angiostrongylus vasorum treated?

A
  • monthly prophylaxis ML (moxidectin or mibemycin) - apr-nov
  • ML or fenbendazole for adults
26
Q

Where does Aelurostrongylus abstrusus live?

A

Lung parenchyma

27
Q

Life cycle of Aelurostrongylus abstrusus?

A
  • L1 in feces of Fe -> (in gastropod IH: L1 -> L2 -> L3) -> ingested by Fe OR ingested by paratenic host (rodent, frogs, birds) & then that is ingested by Fe
  • In Fe, GI tract -> blood -> lungs
28
Q

what is the ecology/epidemiology of Aelurostrongylus abstrusus?

A
  • Fe in BC & Atlantic Canada
  • often asymptomatic, may cause coughing, even death
  • ML, fenbendazole
29
Q

What is important about Crenosoma vulpis?

A
  • Ca & wild canids as DHs
  • adults live in bronchi/bronchioles
  • shed larvae in feces
  • L1 -> L3 in gastropod intermediate hosts
  • Dx: L1 in Baermann or BAL (Ddx Angiostrongylus)
  • Tx: ML, fenbendazole
30
Q

Where does Filaroides (Oslerus) osleri live & who are its hosts?

A
  • Airways, more in trachea, right before they bifurcate
  • wild canids & Ca who hunt them
31
Q

Where does Filaroides hirthi live & who are its hosts?

A
  • lung parenchyma
  • dogs in kennels, often immunosuppressed
32
Q

how are Filaroides (Oslerus) osleri often diagnosed?

A

via bronchoscopy

33
Q

What is the life cycle of Filaroides (Oslerus) osleri & Filaroides hirthi?

A
  • L1 in feces or bal OR internal autoinfection possible OR L1 are shed in saliva & vomit, & may be transmitted to pups via regurgitation feeding -> ingested by another dog
  • atypical life cycle
  • direct
  • ovoviviparous
  • L1 is shed & infective stage
34
Q

What is the pathogenesis of Filaroides (Oslerus) osleri?

A
  • often asymptomatic
  • pathognomonic cough/retch triggered by exercise, cold
  • nodules may obstruct air, cyanosis, & collapse in pups
35
Q

What is the pathogenesis of Filaroides hirthi?

A
  • often asymptomatic
  • clinical only in immunosuppressed (hyperinfection due to autoinfection)
  • occasionally fatal bronchopneumonia
36
Q

How to manage Filaroides?

A
  • decontaminate environment, break vertical transmission (hand rear pups), repeated treatments w/ ML or fenbendazole (label in UK)
37
Q

Which spp are in the subfamily Capillariinae (capillarids)?

A
  • Capillaria aerophila (Eucoleus aerophilus)
  • Capillaria (Eucoleus) boehmi
  • Capillaria (Pearsonema) plica
38
Q

Facts about the Capillariinae (capillarids):

A
  • direct or indirect life cycles (earthworm IH)
  • eggs are the shed stage (have polar plugs)
  • L1 develops in eggs (infective stage like in Trichuris vulpis)
39
Q

Where do Capillaria aerophila (Eucoleus aerophilus) live?

A
  • in Ca & Fe, wild canids
  • adults live in trachea & bronchi, shed eggs in feces
40
Q

Where do Capillaria (Eucoleus) boehmi live?

A
  • Ca & wild canids
  • adults live in nasal & sinus cavities (shed eggs in feces)
41
Q

Where do Capillaria (Pearsonema) plica live?

A
  • Ca & Fe, wild canids
  • adults live in bladder (shed eggs in urine, w/ or w/o cystitis)
42
Q

Facts about Dioctophyme renale:

A
  • DH: Ca, wild canids, mustelids, very rarely people
  • adults can be over 1 m long
  • live in the renal pelvis (generally of the right kidney, but sometimes free in the peritoneum)
  • destroy kidney parenchyma but usually subclinical (unilateral)
  • incidental finding on spay
  • relatively common in MB & Northern ON
43
Q

What is the life cycle of Dioctophyme renale?

A
  • eggs in urine -> (in Oligochaete IH, L1 -> L2 -> L3) -> L3 ingested by Ca OR paratenic hosts which are then ingested by the dog -> become adults in dog
  • LONG PPP - 4-5 months

Parasitology (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions