Parasitology Flashcards
How do you treat adult Fasciola hepatica infections in cattle?
Clorsulon or Albendazole in the fall to kill adults
Not for use in dairy cattle
Not very effective against immature stages
Which of the following parasites is the most likely to result in fly strike?
A. Haemonchus
B. Trichostrongylus
C. Sarcocystis
D. Muellerius
Trichostrongylus colubriformis “Black scour worm” “Bankrupt worm” Small intestine Watery diarrhea predisposes infected sheep to blowfly strike
How is Dictyocaulus different than the other ruminant lungworms?
Dictyocaulus has a direct life cycle - cattle, sheep
Muellerius - snail intermediate - goats
Protostrongylus - snail intermediate - sheep
TX all with fenbendazole or ivermectin products
Type II Ostertagiosis is caused by ________________.
Larvae (L4) in gastric glands (“Moroccan leather”)
Occurs in young adults and calves
Emaciation and profuse watery diarrhea
How are cattle infected by Neospora?
Transplacentally and by ingestion of oocysts
Oocyst contamination in environment from dog definitive host.
Vertical transmission - transplacental infection of fetus; calves that survive in utero infection are persistently infected
Several goats on pasture have developed submandibular edema. Which parasites can cause this clinical sign?
Haemonchus, Ostertagia, Fasciola
T/F: Fascioloides magna eggs can be detected from infected livestock only via fecal sedimentation
FALSE
What stages of Taenia saginata develop in humans?
Adult tapeworm
What is the herd significance of Tritrichomonas foetus infection in cattle?
Reduced reproductive success
How are ruminants infected with Moniezia?
Ingestion of pasture mite infected with larval cysticercus
What is the cause of sorehead in sheep?
Elaeophora schneideri microfilariae
How are ruminant livestock infected by Echinococcus?
Ingest food or water contaminated with dog feces that contains the egg
Which of the following cases is most likely affected by Eimeria?
A. Neonatal (one week old) calf with diarrhea
B. Two-month-old goat with diarrhea
C. One-year-old heifer that has repeatedly failed to get pregnant
D. Five-year-old bull without clinical signs
Two-month-old goat with diarrhea
What is the cause of Texas Fever?
Babesia bigemina
How do you diagnose Taenia saginata in cattle?
Grossly identify the cyst in the muscle at slaughter
T/F: Toxoplasma is a common infectious cause of abortion in cattle.
FALSE
Which time point would you want to treat adult ewes with an anthelmintic to kill encysting larval stages of Haemonchus?
Fall
One of your clients has a large, poorly maintained menagerie that includes dogs, pigs, chickens and sheep. His young son recently had to have a major operation to remove a hydatid cyst from his liver. How did his son acquire this infection?
Name the parasite, specify the parasite stage, and the source of the parasite.
Echinococcus granulosus egg from a dog
Life cycle characteristics of Dictyocaulus include:
- Egg in feces, L3 in snail, adult in bovine lung
- L1 in feces, L3 on pasture, adult in bovine lung
- L1 in feces, L3 in snail, adult in bovine lung
- Egg in feces, L3 in pasture mite, adult in bovine lung
L1 in feces, L3 on pasture, adult in bovine lung
Your client has about a dozen sheep housed in a beautifully wooded ranch in Western WA. One day, one of her beloved sheep develops anorexia for a couple of days before she calls you out to evaluate her.
The only finding is that the sheep is lethargic, so you perform some diagnostics since you suspect parasitic disease. The fecal float, fecal sedimentation, and Baermann are all negative. Blood work shows significantly elevated liver enzymes. Unfortunately, the sheep dies overnight, and you suggest a field necropsy to shed some light on the situation.
On the postmortem exam, you find dozens of large (10 cm) flukes in the liver parenchyma with abundant hepatic necrosis and hemorrhagic tracts. Your client asks you why you weren’t able to diagnose this infection from the fecal exams you performed.
What do you tell your client in response to her question, regarding the life cycle of Fascioloides magna?
Fascioloides magna is only patent in deer; flukes do not fully mature in small ruminant livers and won’t lay eggs.
Choose all the parasites that are associated with submandibular edema (bottle jaw) in ruminants.
- Ostertagia
- Trichuris
- Fasciola hepatica
- Haemonchus
Haemonchus
Ostertagia
Fasciola hepatica
Which of the following parasites induces granulomas in the large intestine of infected ruminants due to the encysted larva L4?
- Ostertagia
- Trichuris
- Oesophagostomum
- Nematodirus
Oesophagostomum
Tritrichomonas foetus infections in a cattle herd is often first indicated by:
- Observing aborted fetuses in the pasture/pen
- Detecting purulent discharge from the penis of the bull
- Detecting purulent vaginal discharge from multiple cows
- Noticing poor reproductive success in the breeding records
Noticing poor reproductive success in the breeding records
What is the significance of the short prepatent period of the HOT complex strongyles?
- Requires a very fresh fecal sample in order to identify strongyle eggs via fecal float
- Neonatal lambs can develop severe disease
- Multiple generations of worms during the grazing season lead to high pasture contamination levels
- Larvae die quickly out on pasture
Multiple generations of worms during the grazing season lead to high pasture contamination levels
How do you diagnose lungworm infection in ruminants?
- Fecal float for eggs
- Fecal float for larva L1
- Baermann on fresh feces to identify larva L1
- Baermann on cultured feces to identify larva L3
Baermann on fresh feces to identify L1
Regarding Taenia saginata:
A. What stage(s) of the tapeworm Taenia saginata do cattle get?
B. What stage(s) of T. saginata do humans develop?
C. How do humans acquire this infection (specify the stage of the parasite and the source)?
Cattle - Larval cysticercus
Humans - adult tapeworm
Human eats beef contaminated by cysticercus
Cysticerci develop in cattle muscles
Taenia saginata
Fluke in hepatic parenchyma of cattle
Fasciola heptatica
Larvae produce granulomas in the large intestine
Oesophagostomum
Adult tapeworm in ruminant small intestine
Moniezia
Small white nematode with distinctively large (150 um) strongyle eggs
Nematodirus
Whipworm in large intestine
Trichuris