NEMATODES: Ascaridoidea spp. Flashcards
While host specific, these intestinal parasites are large, white nematodes with 3 lips, as well as containing thick-shelled eggs (due to a proteinaceous layer), and have a direct life cycle. What nematodes are being described?
Ascarids or roundworms
What species of ascarids can be often associated with heavy infections in puppies before there diagnostics can be performed?
Toxacara canis
What infective stage(s) are associated with ascarids?
L2 or L3
What migrational pattern do most ascarids undertake?
Hepatic-tracheal migrations until the adults reach the small intestine
Will ascarids have a high or low fecundity?
High (producing large amounts of eggs)
In adults, is there a stronger or weaker immunity to ascarid infections?
Stronger, as infectious stages of development will be inhibited, washed out, or arrested since they will be unable to complete their life cycle.
True or False: When hepatic-tracheal migration occurs in fetal pups, the migrating larvae wait in the liver and lungs until the pups are born, at which time they resume their migration across the lungs to the airways
True
True or False: Since somatic infection is very common in adult dogs, veterinarians should assume that essentially every pup is likely to harbor developing ascarids in the small intestine, and thus young animals should be routinely dewormed for Anyclostoma spp.
False, this is true of Toxacara spp.
Due to increased toxacara parasite loads in young puppies, what can occur?
Obstruction leading to intestinal perforations, as well as vomitus and diarrhea containing adults
What methods of transmission can be utilized by T. canis?
Per os, Transmammary (lesser extent than hookworms), PH’s and most importantly transplacental/ prenatal
What is the PPP of Toxacara canis, and how does this relate to puppies younger than 3 weeks of age?
2 (transmammary) or 4 weeks (ingestion), and if they are younger than 3 weeks of age and infected prenatally in utero, than they will not shed any eggs in their feces
What treatment and preventative methods can be used to decrease T. canis infections?
Routine deworming of the dam and puppies (at 2, 4, 6, and 8 wks of age), managing the environment (sanitation, removing fresh feces, etc.), and treating to eliminate the L4’s and L5/IA’s before egg shedding
Since T. canis is zoonotic, what can occur in regards to larval migrations?
Can lead to OCL (ocular larval migrans or ocular toxocaraiasis) and VCL (visceral larval migrans) in humans
Who is the DH for T. canis, ans who is an example of an AH?
DH = Dogs
AH = Humans
Who is the DH for Toxocara cati?
Cats
What difference is noted in the transmission of T. canis and T. cati?
There is no transplacental/ prenatal transmission of T. cati leading to the effection of older cats
Can paratenic hosts be associated with both T. canis and T. cati?
Yes
Who are the DH’s for Toxacaris leonina?
Cats and dogs
What is the difference in the structure of the eggs of T. canis, T. cati, and T. leonina?
T. leonina has a smooth, ovoid, thick-shelled egg, as it lacks a proteinaceous layer, but also has a more vacuolated internal appearance
Eggs shed by adult Toxacara leonina have larvae present in what stage, which are released into the small intestine following consumption of the DH’s?
L2
What is the PPP of Toxacaris leonina?
8 - 11 weeks
What is the PPP of Toxacara cati?
4 weeks transmammary, 6 - 8 weeks if ingested
Will you have an increase or decreased immunity with T. leonina? Increased or decreased pathogenicity?
Decreased immunity and pathogenicity, as they migrate locally and are not attributed with lung diseases (pneumonia, etc.)
Who are the DH’s, PH’s, and AH’s assocaited with Baylisascaris procyonis?
DH = Raccoons
PH = Birds, rabbits, and other small mammals
AH = Dogs
After ingestion of infective eggs, larvae of B. procyonis, like those of other ascarids, migrate through the abdominal organs and the musculature, but have a propensity to invade what tissues (resulting in a severe pathology)?
The CNS
Who are the DH’s of Parascaris equorum?
Equids
Which transmission is only utilized by Parascaris equorum?
A) Cutaneous
B) Per os
C) Transmammary
D) Prenatal
B) Per os
What is the PPP of Parascaris equorum?
10 - 12 weeks (2 - 3 months)
Which diagnostic test should be utilized for Parascaris equorum confirmation?
McMaster fecal flotation
True or False: Larvated Parascaris eggs remain viable for 10 years or more, so one patent infection on a premise can affect several future generations of foals
True
Similarly to other ascarids, P equorum can lead to what conditions?
Obstruction, performation, intusseption, poor coat, and reduced weight gain
Is there any associated antihelminthis resistance with Parascaris equorum?
Yes
What other Parascaris sp. can Parascaris equorum be mistaken for, and would require genetic karotyping techniques to see a 0.16% difference in chromosomal make-up?
Parascaris univalens
Parascaris univalens more commonly infects younger or older horses?
Older or adult horses
Parascaris equorum is associated with infecting younger or older horses?
Younger (foals)
Who are the DH’s and IH’s for Ascaris suum?
DH = Pigs
IH = Earthworm, beetle
What modes of infection or transmission are associated with Ascaris suum?
Per os and paratenic hosts only
True or False: There is no consequence of touching adult Ascaris suum with your bare hands.
False, it leads to a delayed allergic response
What is the PPP of Ascaris suum?
6 - 8 weeks (1 - 2 months)
Does Ascaris suum follow the majority of ascarids in hepatic-tracheal migration?
Yes
Upon necropsy, what organ will be condemned resulting in production losses, as a result of A. suum infections?
The liver
Ascaris suum will exhibit what respiratory condition due its hepatic-tracheal migration route from the intestines?
Pneumonia, more severe in piglets under 4 months of age
Is T. canis or A. suum more persistent and resistant?
Ascaris suum
What can be done to treat against Ascaris suum infections in both outdoor and indoor production units?
Reduce/ eliminate sources of infection, treat and wash sows pre-farrowing (giving birth), and treat weaned piglets with antihelminthics in feed.
T. canis can’t be treated with which of the following antihelminthics?
A) Fenbendazole
B) Ivermectin
C) Selamectin
D) Tricalbendazole
D) Tricalbendazole, which is only for Fasciola spp. which are trematodes
