ACVM Parasitology Boards > Helminth (Spirurida) > Flashcards

Helminth (Spirurida) Flashcards

Georgi's (123 cards)

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1
Q

What are the two suborders of the order Spirurida?

A

Camallanina and Spirurina

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2
Q

What type of intermediate host is required for members of the Spirurida?

A

Arthropod, either a crustacean or an insect

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3
Q

How does a definitive host acquire spirurid infections?

A

By ingesting infected arthropods or paratenic hosts

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4
Q

What is the superfamily included in the suborder Spirurina?

A

Filarioidea

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5
Q

What is Dracunculus?

A

A genus of the suborder Camallanina, a parasite of subcutaneous tissues

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6
Q

What is the maximum size of female Dracunculus?

A

Up to 120 cm

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7
Q

What happens when water wets the ulcer formed by a female Dracunculus?

A

The female projects her body and prolapses a length of uterus to discharge larvae

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8
Q

How long does it take for Dracunculus to mature?

A

About 1 year

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9
Q

What species of Dracunculus infects humans?

A

Dracunculus medinensis, known as the Guinea worm

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10
Q

What is the significance of Cyclops in the life cycle of Dracunculus?

A

Larvae become infective if ingested by Cyclops copepods

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11
Q

What is the role of frogs in the infection of D. insignis?

A

Frogs serve as paratenic hosts for increased infection risk

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12
Q

What is the primary species of Gnathostoma that affects dogs in Asia?

A

Gnathostoma spinigerum

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13
Q

How do Physaloptera spp. infect their hosts?

A

Via ingestion of larvated eggs by coprophagous beetles or other insects

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14
Q

What are the treatment options for Physaloptera infections in dogs?

A

Fenbendazole, ivermectin, and pyrantel pamoate

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15
Q

What is Gongylonema and where does it typically reside?

A

A genus of parasites found in the esophagus and rumen of ungulates

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16
Q

What is the transmission method for Gongylonema spp.?

A

Infection occurs through ingestion of infected insects

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17
Q

What is Spirocerca lupi known for?

A

A parasite found in fibrous nodules in the esophagus or stomach of canids

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18
Q

What is a common treatment for dogs infected with S. lupi?

A

Milbemycin oxime

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19
Q

What is the prevention strategy for S. lupi infection?

A

Use of moxidectin and milbemycin oxime

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20
Q

What are the three species of Habronema that affect equines?

A

Draschia megastoma, Habronema muscae, Habronema microstoma

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21
Q

What is the size difference between D. megastoma and Habronema spp.?

A

D. megastoma is about 13 mm; Habronema spp. are larger, 22 to 25 mm

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22
Q

Fill in the blank: The definitive host of Dracunculus can become infected by ingesting _______.

A

Cyclops organisms

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23
Q

True or False: Dracunculus medinensis was near extinction due to a massive international campaign.

A

True

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24
Q

What are the two species of parasites discussed that affect the equine stomach?

A

Draschia megastoma and Habronema spp.

Draschia megastoma is about 13 mm long, while Habronema spp. are larger, measuring 22 to 25 mm.

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25
What is the length difference in spicules between H. muscae and H. microstoma?
H. muscae has a left spicule five times longer than the right; H. microstoma has a two-fold disparity. ## Footnote This indicates significant morphological differences between the two species.
26
What type of lesions do Draschia and Habronema larvae cause?
Persistent cutaneous granulomas. ## Footnote These are colloquially known as 'swamp cancer,' 'bursatti,' 'summer sores,' and 'esponja.'
27
What is the primary treatment for adult Habronema and Draschia spp.?
Ivermectin and moxidectin. ## Footnote Ivermectin is specifically approved for treating summer sores caused by these larvae.
28
What is the main intermediate host for Thelazia spp.?
Musca autumnalis (face fly). ## Footnote The Oriental face fly, Musca hervei, is an intermediate host in Japanese cattle.
29
What are the treatment options for Thelazia in cattle?
* Doramectin at 0.2 mg/kg * Tetramisole at 12.5 to 15 mg/kg * Levamisole at 5 mg/kg ## Footnote These treatments can be administered subcutaneously or intramuscularly.
30
What is the primary vector for T. californiensis?
Muscoid latrine flies, Fannia canicularis and Fannia benjamini. ## Footnote Drosophilid fruit flies may also explain ocular cases in the western United States.
31
What is the main family of parasites that includes dog heartworm?
Onchocercidae. ## Footnote This family also includes important nematode parasites of humans in tropical climates.
32
What are the two genera of importance in the family Filariidae?
* Parafilaria * Stephanofilaria ## Footnote These genera differ from onchocercids in their location and type of offspring produced.
33
What is the primary concern regarding Dirofilaria immitis?
It is a deadly parasite of dogs. ## Footnote Resistance to macrocyclic lactones used for prevention has been confirmed.
34
What is the typical size range for adult Dirofilaria immitis?
* Males: 12 to 20 cm * Females: 25 to 31 cm ## Footnote These worms can be lethal even in low numbers, especially in ferrets.
35
What is the significance of the term 'coin lesions' in relation to human infection by Dirofilaria immitis?
They are misinterpreted as neoplasia. ## Footnote This can lead to unnecessary thoracic surgery.
36
How is the life history of Dirofilaria immitis characterized?
It involves many species of mosquitoes as intermediate hosts. ## Footnote Mosquito control is crucial in preventing the spread of heartworm.
37
What was a common disease in the United States until malaria disappeared?
Malaria ## Footnote Malaria disappeared when the population density of suitable mosquitoes fell below the level necessary for transmission.
38
What contributes to the reduction of mosquito populations?
Drainage of swamps, construction of roads, intentional mosquito abatement ## Footnote These efforts were made for agricultural purposes.
39
What is the primary host for Dirofilaria immitis?
Dogs
40
How long can adult heartworms survive and produce microfilariae?
Up to 5 years
41
What is the role of mosquitoes in the life cycle of Dirofilaria immitis?
Intermediate hosts for microfilariae
42
What is the first stage of larval development in mosquitoes?
Infective third-stage larvae
43
How soon after the bite of an infecting mosquito does the molt from third-stage to fourth-stage larva occur?
Within 3 days
44
Where do fourth-stage larvae reside after infection?
Subcutaneous connective tissues and muscles of the abdomen or thorax
45
When do immature adult heartworms migrate to pulmonary arteries?
70 days after infection
46
What is the prepatent period for Dirofilaria immitis?
6 to 9 months
47
What percentage of dogs in Mississippi shelters were found to have microfilariae?
22.6%
48
What is a significant consequence of heartworm infection in dogs?
Chronic venous congestion, hepatic cirrhosis, ascites
49
True or False: Heartworm is a reportable disease in all U.S. states.
False
50
What is the typical length of adult heartworms found in dogs?
20 to 40 mm when first reaching the right side of the heart
51
What is the result of obstruction caused by adult heartworms?
Pulmonary hypertension and right-sided heart failure
52
What diagnostic tests are used for heartworm infection in dogs?
Antigen detection tests, finding microfilariae in blood
53
Fill in the blank: Adult dogs that have not been on preventive therapy should be examined first to verify that they are heartworm _____.
negative
54
What is the recommended frequency for testing dogs on year-round heartworm prevention?
Yearly
55
What is the challenge with testing large populations of dogs for heartworm?
Greater chance of false-positive results
56
What is the significance of the SNAP 4Dx Plus HW antigen test?
Assesses accuracy in areas with low prevalence of heartworm infection
57
What can happen if a dog is bitten by an infected mosquito at birth?
Worms may be too young to have circulating antigen or microfilariae
58
What is the average number of heartworms associated with moderate to severe heartworm disease in dogs?
About 50 worms
59
What can cause acute episodes of respiratory distress in dogs with heartworm?
Pulmonary embolism
60
What is the role of the Companion Animal Parasite Council (CAPC) in heartworm prevalence data?
Reports positive samples from dogs tested for heartworm
61
What is the significance of year-round heartworm prevention in dogs?
It ensures that dogs are negative for heartworm infection, leading to doubts about the value of positive tests in these populations.
62
What was the positive rate of the SNAP 4Dx Plus HW antigen test in Scandinavia?
0.12% (95% confidence interval of 0.07% to 0.19%)
63
What was the observed specificity of the SNAP 4Dx Plus HW antigen test in Scandinavia?
99.88% (95% confidence interval of 99.81 to 99.93%)
64
What was the positive rate of the SNAP 4Dx Plus HW antigen test in California?
0.58% (95% confidence interval of 0.55% to 0.60%)
65
True or False: The positive rate in California was significantly higher than in Scandinavia.
True
66
What is the overall positive predictive value of the SNAP 4Dx Plus Test for HW in California?
82.02%
67
What should be done if a dog tests positive for heartworm using the SNAP 4Dx Plus Test?
Further work is required to prove that the dog is not infected, such as checking for microfilariae or using additional tests.
68
What complications arise from blocking antibodies during heartworm antigen testing?
Interference with antigen detection and reduced serum volume for testing.
69
What are the two types of anthelmintics used for treating D. immitis?
* Adulticides for adult worms * Microfilaricides for circulating microfilariae
70
What is the approved treatment for dogs infected with adult heartworms?
Melarsomine dihydrochloride
71
How is melarsomine administered to dogs with mild to moderate clinical signs?
Two intramuscular injections (2.5 mg/kg) given 24 hours apart.
72
What happens to heartworms after arsenical therapy?
They die slowly and are carried to the lungs where they lodge and obstruct circulation.
73
What is the only approved product for removing microfilariae from circulation?
Combination of 2.5% moxidectin with 10% imidacloprid.
74
What does the American Heartworm Society recommend for dogs with heartworm infection?
They should be placed on a regimen of monthly heartworm prevention and treated with doxycycline and melarsomine.
75
What is the purpose of the 2-month wait before the first arsenical treatment?
To allow developing worms to become old enough to be effectively killed.
76
What is the recommended prevention strategy for heartworm in dogs?
All dogs should be on year-round prevention and checked annually for heartworm.
77
What should be done for dogs with persistent microfilaremias despite heartworm therapy?
Start them on monthly 10% imidacloprid and 2.5% moxidectin, and consider doxycycline if microfilariae persist.
78
What is the importance of using a macrocyclic lactone in heartworm prevention?
It helps to prevent heartworm infections and reduces the percentage of dogs testing positive.
79
What has been observed regarding resistance to macrocyclic lactones in D. immitis?
Reports of 'product prevention failures' indicate resistance has developed.
80
What should be done if a dog is bitten by an infected mosquito while on heartworm prevention?
Continue treatment for 12 months to ensure protection.
81
What is the effect of doxycycline on treating heartworm infections?
It helps remove the endosymbiotic bacteria Wolbachia, assisting in removing microfilariae.
82
What is the recommended annual protocol for heartworm testing in dogs?
Dogs should be checked with an antigen detection test annually.
83
Fill in the blank: The SNAP 4Dx Plus HW antigen test is used to detect _______.
heartworm infection
84
What is a potential unintended consequence of non-targeted doxycycline use?
Development of resistance in other pathogens.
85
What are the potential reactions a dog may experience after arsenical treatment?
* Vomiting * Fever * Respiratory distress
86
What is the recommended duration for administering doxycycline to dogs after heartworm exposure?
1 month ## Footnote Doxycycline is used to prevent potential transmission of heartworm disease.
87
What percentage of imidacloprid with permethrin may not prevent all mosquito bites in dogs?
10% ## Footnote This combination may not be fully effective against mosquitoes.
88
What is the primary difference in heartworm infection between cats and dogs?
Cats tend to harbor very few adult worms and remain amicrofilaremic ## Footnote This affects the reliability of blood tests for detection.
89
What syndrome can cats develop due to heartworm migration in their lungs?
HARD (heartworm-associated respiratory disease) ## Footnote This occurs even without patent infection.
90
What are the available products for heartworm prevention in cats?
* Ivermectin * Milbemycin oxime * Selamectin * Moxidectin with imidacloprid ## Footnote These can be administered topically or orally monthly.
91
What is Dirofilaria repens?
A parasite of dogs in Eurasia and Africa ## Footnote It lives in subcutaneous tissues and is transmitted by mosquitoes.
92
Where has Dirofilaria repens been found besides southern Europe?
Eastern European countries like Ukraine, Russian Federation, and Belarus ## Footnote Its range has expanded significantly.
93
How many human cases of ocular and dermal dirofilariasis have been reported in Europe due to D. repens?
More than 1000 ## Footnote This highlights the zoonotic potential of the parasite.
94
What is the significance of antigen-antibody disassociation in cats infected with heartworms?
It may assist in the detection of circulating antigen ## Footnote This is particularly relevant when cats have few worms.
95
What is the treatment for horses infected with Onchocerca cervicalis?
Ivermectin or moxidectin ## Footnote These treatments eliminate microfilariae from infected horses.
96
What are the symptoms associated with Onchocerca lupi infections in dogs?
* Conjunctivitis * Exophthalmos * Periorbital swelling * Photophobia * Discomfort * Lacrimation * Discharge ## Footnote Chronic cases may involve embedded worms in nodules or cysts.
97
What is Acanthocheilonema reconditum?
A nonpathogenic parasite found in dogs and other canids ## Footnote Its microfilariae can be confused with those of D. immitis.
98
What is the life cycle of Acanthocheilonema reconditum?
Develops to infective stage in fleas and lice ## Footnote Microfilariae develop into third-stage larvae in 7 to 14 days.
99
How can Acanthocheilonema reconditum microfilariae be differentiated from D. immitis?
More slender body, lack of taper at the anterior extremity, larger cephalic hook ## Footnote Accurate diagnosis is crucial before treatment.
100
What is the primary vector for Cercopithifilaria species?
Hard ticks, specifically Rhipicephalus sanguineus ## Footnote These species are transmitted through tick bites.
101
What symptoms are associated with Elaeophora schneideri infections in sheep?
Patches of moist, exudative dermatitis with crust formation ## Footnote This occurs in high-altitude summer ranges.
102
What is the typical habitat for Setaria species?
Abdominal cavities of artiodactyls and equines ## Footnote They are medium to large worms.
103
What is the typical size of adults found in the carotid, iliac, and mesenteric arteries?
Up to 120 mm long
104
What percentage of moose in Wyoming are reported to be infected?
Nearly 50%
105
What type of hosts are Tabanids classified as?
Cyclodevelopmental intermediate hosts
106
Which subfamily do Setaria belong to?
Setariinae
107
Where are Setaria spp. typically found in their hosts?
Abdominal cavities of artiodactyls and equines
108
What are the two large white parasites of cattle and horses?
* Setaria labiatopapillosa * Setaria equina
109
How is Setaria infection transmitted between hosts?
By mosquitoes
110
What do sheathed microfilariae of Setaria spp. show up on?
Blood smears
111
What is a potential consequence of migrating Setaria larvae in their hosts?
Serious neurologic disease
112
What unusual location can actively motile Setaria adult worms be observed?
Anterior eye chamber of horses
113
What is the name of the condition caused by Parafilaria multipapillosa in horses?
Parafilariosis or 'summer bleeding'
114
What type of tissues do Parafilaria spp. live in?
Subcutaneous and intermuscular connective tissues
115
What happens to the blood when Parafilaria nodules bleed?
Escapes in fine drops, runs off in streaks, dries in brown crusts
116
When does active bleeding occur in horses affected by Parafilaria?
During daylight hours, especially in direct sunshine
117
What is the primary vector identified for P. bovicola in South Africa?
* Musca lusoria * Musca fasciata * An undescribed Musca spp.
118
What significant impact do subcutaneous lesions from P. bovicola cause?
Substantial trim losses at slaughter
119
What is the main site of lesions caused by Stephanofilaria stilesi in cattle?
Ventral abdomen
120
What is the size of adults of Stephanofilaria stilesi?
Less than 6 mm long
121
What condition does Stephanofilaria assamensis cause in cattle in India?
Humpsore
122
Where do the infective larvae of Stephanofilaria stilesi develop?
In the horn fly, Haematobia irritans
123
Fill in the blank: The infection of Setaria spp. is often encountered during ______.
Abdominal surgery or necropsy
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