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
Fluke in bile ducts of cattle
Thysanosoma actinoides
Nematode that causes anemia in sheep and goats
Haemonchus
Adult worm in carotid artery
Elaeophora schneideri
L4 larva deep in abomasal glands
Ostertagia
T/F: Trichuris is typically more clinically severe in camelids than it is in ruminants.
TRUE
T/F: Elaeophora microfilariae are transmitted by direct contact between infected animals.
FALSE
T/F: Parelaphostrongylus tenuis is associated with severe neurological disease in alpacas.
TRUE
T/F: Fasciola hepatica is diagnosed by fecal sedimentation.
TRUE
A local feedlot manager has been working with you recently to help improve the health of his cattle. One of the most recent issues you are working through is an uptick in the number of clinical coccidiosis cases. He was having an outbreak bloody diarrhea and a small number of animals died. Postmortem examination on two of the animals that had died revealed severe hemorrhagic enteritis. Histopath ology confirmed large numbers of coccidia in the epithelial cells of the intestines.
a. What is the genus of coccidia involved?
b. Name two speci!c management strategies you are going to suggest to the manager.
Eimeria
Rigorous sanitation - decrease manure concentration; don’t feed on the ground
Separate animals with diarrhea
T/F: Cryptosporidium parvum in ruminants is treated with amprolium.
FALSE - no effective treatment
Choose the following true statement regarding the “spring rise” transmission cycle of ruminant strongyles.
- Ewe fecal egg output increases around lambing season
- Recently weaned lambs increase egg shedding and contribute to pasture larva contamination
- Inhibited larva emerge and develop to adult egg-producing worms in early spring
- High summer temperatures and reduced moisture levels reduce survival and transmission of L3 on pasture
- All of the above
All of the above
One of your clients in western WA has a small herd of cattle that he raises for beef to sell at his local farmer’s market. His butcher recently let him know that several of his cattle have liver fluke infections. The butcher describes “pipe stem liver” lesions. How do you suggest he attempts to control disease in his herd?
- Incorporate ivermectin into the fall herd anthelmintic treatment schedule
- Incorporate Clorsulon or Albendazole into the fall herd anthelmintic treatment schedule
- Suggest environmental molluscicide treatment to control the snail intermediate host
- Incorporate fenbendazole or praziquantel into the fall herd anthelmintic treatment schedule
- There is no effective anthelmintic available for this parasite.
Incorporate Clorsulon or Albendazole into the fall herd anthelmintic treatment schedule
A client of yours calls to explain that he is seeing little white rice grains in the feces from his cattle. Assuming this is a tapeworm infection and he is actually seeing proglottids, what is the most likely culprit?
- Thysanosoma
- Taenia saginata
- Moniezia
- Echinococcus
Moniezia
You get called out to a farm that that rescues goats. They just brought in 14 goats about 2 weeks ago, and would like you to examine these goats and make sure everyone is healthy. The !rst thing you note is that 3 of the animals have pretty severe bottle jaw. You pull out your trusty FAMACHA chart and determine that these 3 animals are extremely pale. What is your next step?
- Do a quantitative fecal float to determine which animals need to be treated with anthelmintics
- Treat the pale animals immediately with decoquinate
- Treat the pale animals immediately with fenbendazole
- Immediately move all the animals to the clean, unused pasture
Treat pale animals immediately with fenbendazole
You are a veterinarian at a large dairy in central WA. The manager notes that 11 cows aborted in the last 2 weeks after they were moved together from a barn to the dry cow area of the farm. The abortions occurred around 160 days gestation (approximately mid-gestation). Fetal samples were sent to WADDL, where Dr. Haldorson finds inflammation in the brain, heart, and placenta, and confirms the presence of protozoa in the brain. Choose the two possible methods of Neospora transmission.
- Ingestion of food or water contaminated with dog feces containing oocysts
- Arthropod-borne transmission (black flies)
- Transplacental transmission of bovine fetuses
- Transmammary transmission of neonatal calves
Ingestion of food or water contaminated with dog feces containing oocysts
Transplacental transmission of bovine fetuses
You are a veterinarian at a large dairy in central WA. The manager notes that 11 cows aborted in the last 2 weeks after they were moved together from a barn to the dry cow area of the farm. The abortions occurred around 160 days gestation (approximately mid-gestation). Fetal samples were sent to WADDL, where Dr. Haldorson finds inflammation in the brain, heart, and placenta, and confirms the presence of protozoa in the brain.
Regarding the dairy abortions, which of the two transmission methods is most likely in this case and why?
Vertical transmission - transplacental infection of fetus causes abortion
You are a veterinarian at a large dairy in central WA. The manager notes that 11 cows aborted in the last 2 weeks after they were moved together from a barn to the dry cow area of the farm. The abortions occurred around 160 days gestation (approximately mid-gestation). Fetal samples were sent to WADDL, where Dr. Haldorson finds inflammation in the brain, heart, and placenta, and confirms the presence of protozoa in the brain.
Regarding the dairy abortions, what management strategy will you suggest to the dairy manager to help prevent future infections?
Do not keep calves from seropositive cows as replacements
Do not feed carcasses, placenta to dogs
Which of the following situations would it be the most appropriate to institute the FAMACHA system as an integrated component of parasite control?
- A 10,000 head “flock of sheep as a part of a yearly integrated parasite management strategy
- A 20-head herd of goats with a clinical history including moderate numbers of strongyle egg counts, and several animals with bottle jaw
- A 20-head herd of goats with a clinical history of high strongyle egg counts, decreased weight gains, and diarrhea
- A 100-head “flock of sheep with periodic outbreaks of fetid diarrhea
A 20-head herd of goats with a clinical history including moderate numbers of strongyle egg counts, and several animals with bottle jaw
Which is true regarding Toxoplasma infection in ruminants?
- Cattle are highly susceptible to infection and abort when infected during gestation
- Small ruminants are highly susceptible to infection and abort when infected during gestation
- All ruminant species are highly susceptible to infection and abort when infected during gestation
Small ruminants are highly susceptible to infection and abort when infected during gestation.
T/F: Sarcocystis infection is a major cause of abortion in ruminants.
FALSE
How do ruminants get infected with liver flukes?
- Ingestion of the snail intermediate host
- Ingestion of the fluke egg on pasture
- Ingestion of aquatic plants with encysted metacercariae
- Direct implantation from the alien overlords
Ingestion of aquatic plants with encysted metacercariae
How do you diagnose Fascioloides magna in infected ruminants?
- Fecal float to identify egg
- Fecal sedimentation to identify fluke egg
- Necropsy
Necropsy
How does a human get infected with the hydatid cyst of Echinococcus?
- Ingestion of infected undercooked meat from livestock or venison
- Ingestion of the egg from infected dog feces
- Ingestion of Echinococcus eggs from an infected pig or ruminant
- Ingestion of the hydatid cyst from dog feces
Ingestion of the egg from infected dog feces
Where do the adult and microfilariae of Elaeophora reside in sheep?
- Adult in intestine; Microfilariae in blood
- Adults in lungs; Microfilariae in skin
- Adult in peritoneum; Microfilariae in blood
- Adult in large blood vessels; Microfilariae in skin
You have a client that owns an alpaca farm that has been struggling with multiple management issues. Several of the alpacas are underweight. As part of your initial visit, you do a fecal float and see the following eggs. What are they?
- Trichuris eggs
- Capillaria eggs
- Strongyloides eggs
- Trichuris and Capillaria eggs
Trichuris and Capillaria eggs
Abomasitis due to inhibited L4s is caused by:
Ostertagiosis Type II
Which parasite causes anemia in ruminants?
Haemonchus
Which parasite condition causes abomasitis due to adult worms?
Ostertagiosis Type I
Which group is most likely to have problems with Ostertagia - beef cattle on pasture or dairy cattle in a milking parlor?
Cattle on pasture
Which of the following time points would you want to treat adult ewes with an anthelmintic meant to treat adult Haemonchus?
- Early-mid spring
- Mid-late spring
- Summer
- Fall
Early-mid spring
Haemonchus is is associated with:
- Anemia
- Constipation
- Bottle jaw / submandibular edema
- All of the above
All of the above
Haemonchus contortus:
- Adult worms consume blood
- L4 alter intestinal pH
- eggs are larvated in fresh fecal samples
- all of the above
Adult worms consume blood
Ostertagia ostertagii:
- Immunity in cows develops after about two years on pasture
- resistance to antihelmintics is beginning to emerge
- L3 survive winter on pasture
- All of the above
All of the above
Type II Ostertagiosis:
- Calves only
- Destruction of parietal cells
- Relatively numerous eggs in fecal samples
- All of the above
Destruction of parietal cells
To help prevent Type I ostertagiosis relative to the climate in the northwest:
- Treat cows with anthelmintics at parturition, treat calves in late spring/early summer
- Treat calves in the fall to eliminate L4s from mucosa
- Treat cows in the fall to eliminate L4s from mucosa
- All of the above
Treat cows with anthelmintics at parturition, treat calves in late spring/early summer
Trichostrongylus colubriformis:
- Large intestine
- Anemia
- Fly strike
- All of the above
Fly strike
Nematodirus spp. cause the most serious disease condition:
- in ewes as adult worms
- in lambs as L4s
- in lambs as adult worms
- in lambs due to transmammary transmission
In lams as adult worms
Lungworm infections are diagnosed in ruminants by use of
- fecal floats
- the Baermann funnel technique
- fecal sedimentation
- all of the above
Baermann
Dictyocaulus viviparus:
- causes severe respiratory disease as an L4
- chronic infection is a common finding in goats
- a vaccine protects goats from clinical disease
- all of the above
Causes severe respiratory disease as an L4
Elaeophora schneideri:
- microfilaria in the skin cause behavior leading to “sore head” in sheep
- adults often migrate beyond the carotid artery and block blood flow to facial tissues in mule deer
- elk are the natural definitive host
- all of the above
Microfilaria in the skin cause behavior leading to “sore head” in sheep
Fasciola hepatica can cause:
- anemia
- red water (activation of Clostridium novyii)
- bottle jaw / submandibular anemia
- all of the above
All of the above
Fascioloides magna infections lead to:
- death in sheep and goats
- mature adult infections in cattle
- mature adult infections in white tailed deer
- all of the above
?
Moniezia spp.:
- generally non-pathogenic, heavy infections in young animals can cause mild ill-thrift, diarrhea
- have a cysticercoid intermediate form and intermediate host the pasture mite
- treat with fendbendazole or albendazole
- all of the above
All of the above
Dog/sheep cycle of tapeworms:
- feed dogs meat scraps of sheep to induce immunity against tapeworms
- a cysticercoid develops in sheep
- hydatid cysts often present as large cysts in sheep liver
- all of the above
Hydatid cysts often present as large cysts in sheep liver
Taenia saginata:
- an unusually high infection in feedlot cattle from the NW United States
- causes neurocysticercosis in cattle
- causes neurocysticercosis in people
- all of the above
Unusually high infection in feedlot cattle from NW United States
Coccidiosis in ruminants:
- is of moderate to low importance in the NW
- can be initiated by stressful conditions
- is most serious upon synchronous development of L4s in tissues
- all of the above
Can be initiated by stressful conditions
Cryptosporidium parvum:
- effective immunity generally develops following primary exposure
- cause neonatal scours in dairy/confinement and has no effective treatment
- has importance as a public health significance due to its ability to have self-limiting diarrhea in immunocompetent people and death in those who are immunocompromised
- all of the above
All of the above
Neospora caninum in cattle:
- opossums serve as the definitive host
- vertical infections from cows to calves, leading to abortions
- use bulls less than four years old to prevent transmission
- all of the above
Vertical infections from cows to calves, leading to abortions
Tritrichomonas foetus in cattle:
- early abortion
- vertical infections from cows to calves, leading to abortion
- use ipropran to eliminate the infection from bulls
- all of the above
Early abortion
Coccidiosis in ruminants:
Ingestion of ___________ (parasite stage) from the environment leads to the initial infection of intestinal epithelial cells, followed by _________ in host epithelial cells producing structures called schizonts that contain many merozoites.
Acute coccidiosis due to Eimeria in cattle leads to this clinical sign: _______________.
Eimeria infection in sheep and goats leads to this clinical sign: _______________.
Clinical signs can develop due to ________ , usually while calves are ________.
Immunity usually develops by ____________.
Oocysts Asexual amplification Bloody diarrhea Not bloody diarrhea Stress Less than 6 months Older than 1-2 years
