12 - Parasites

Teladorsagia

What is the new name for the brown stomach worm (ostertagia) in sheep? O. ostertagi is in cattle and camelids, and T. circumcincta is in SRs. There are two types of clinical disease. There will be less HCl production, with increased gastrin and less pepsin, causing maldigestion. This and gastritis are the main signs, plus anorexia. It is found in the abomasum.

Abomasum

Which section of the stomach is where teladorsagia/ostertagia is found on postmortem in the ruminant?

Strongyles

Haemonchus, Ostertagia, and Cooperia are collectively known as what worms? They are the primary cause of PGE, reduced weight gain, and diarrhea in cattle, and have similar thin-shelled eggs. They are nematodes. Wisconsin and other flotation techniques produce eggs that are indistinguishable, and must be cultured or molecularly tested.

L3

Which stage of strongyles is infective, develops in dung/soil, and is ingested, developing to L4 in the animal?

Haemonchus

Which nematode is in the abomasum and also called barber pole worm? It is the most economically important GI nematode in SRs and can remove up to 20% of RBC volume/day in lambs. It is more common in SRs and camelids, prevents immune development, has a PPP of 3 weeks, and thrives in moist-warm environments. There is no diarrhea, but there is anemia and protein loss. Flotation is not specific, so FAMACHA, necropsy and PNA staining (specific) can/should also be done.

I

Which type of Teladorsagia disease has only adult males? It is the normal nematode life cycle, occurs in normal weather, has a PPP of 21 days/3 weeks, and is found in fecals. It occurs in young stock.

II

Which type of Teladorsagia disease involves arrested L4 stage worms? It occurs in adverse weather when the worms go into hypobiosis, clinical signs do not appear until good weather returns, and they are not found on fecals. There will be simultaneous awakening of L4 worms, acute abomasitis, gastric gland destruction, and no eggs due to young worms only. If affects yearlings-young adults, and causes increased abomasal pH, increased serum pepsinogen, and larvae, worms, and moroccan leather nodules on necropsy.

Mild

What Teladorsagia cases will have reduced growth/production and ill thrift?

Severe

What Teladorsagia cases will have profuse diarrhea, weight loss, anemia, hypoproteinemia, and death?

Cooperia

Which SI worm is the most prevalent nematode in cow/calf operations due to increasing resistance? It causes diarrhea, weight loss, poor weight gain, and ill thrift in juveniles/calves, and stimulates a better immune response as animals age.

Nematodirus

Which intestinal worm is infective as an L3 within the egg (ingested before hatching)? Hatching is triggered by a period of cold followed by warmer conditions. Signs include diarrhea, colic, and sudden death, and diagnosis is with very large eggs on fecal flocation (not a strongyle). They are low egg shedders so any eggs seen are diagnostic. Treatment is with high doses of fenbendazole.

Fenbendazole

Which antihelmintic is given in high doses to treat Nematodirus?

Coccidia

Isospora and Eimeria are both known as what organism, a protozoan? They are species specific and occur from dam-peers contaminating the environment. Infection is through ingestion of sporulated oocytes, which takes time (up to a week). Diagnosis is with flotation or necropsy/histopathology. Centrifugation and McMasters are the best methods antemortem. Only treat if there are clinical signs, and treat with sulfas/amprolium/ponazuril (expensive) plus oral/IV fluids and support care. Corid can be given in water to kill them, and Bovatec for animals other than camelids and horses. It is better to treat the animal than the water.

Mild

Which type of coccidiosis will have malabsorptive diarrhea, yellow-white in color, plus dehydration, lethargy, and anorexia?

Severe

Which type of coccidiosis will have PLE and inflammatory diarrhea that is profuse, with blood, fibrin, and mucus? There will be fever then hypothermia, lethargy, recumbency, rectal prolapses, and commonly death. An intestinal fibrin/mucosal cast may also form.

1

Onset of coccidiosis diarrhea will be at what week in piglets?

3

Onset of diarrhea from coccidiosis will be at what week in calves?

2-3

Onset of diarrhea from coccidiosis will be at about what week in lambs, kids, and crias?

C. parvum

What protozoan affects up to 100% of dairy calves, has a PPP of 2-7 days, has peak sheeding at 4-12 days old and at weaning, and is less infective of beef calves? It also affects lambs, crias, kids, and piglets. It can be zoonotic and oocysts are immediately infective. Onset is usually 5-10 days, diarrhea can last up to 2 weeks despite treatment, and anorexia, lethargy, recumbency, and death from dehydration/acidosis will occur. Special signs, fecal flotation, and presumptive signs-based diagnosis can all be done. There are no effective drugs in the US, but halofuginone can be used for shedding/diarrhea in the EU. Support and acidosis treatment is essential. The infective dose is 30 oocytes. Hygiene and environmental care is important.

2

How many weeks after drenching should an FEC be repeated? The goal is to have 90% reduction.

20

What percentage of a herd often has 80% of the parasites? FEC and clinical signs (FAMACHA only for Haemonchus) are used to find these animals.

Oral

What route is best to treat GI parasites due to less resistance? Combination therapy, increasing contact time, and weighing the animals is best.

Resistant

Are Scottish blackface, Red Maasai, Romanov, St. Croix, Barbados Blackbelly, and Katahdin (sheep), and Spanish, Kiko, Tennessee Fainting, and Myotonic (goat) breeds more worm resistant or susceptible?

Contaminated

After introducing a new animal and dry-lotting, testing, and treating, should you place the animal in a clean or contaminated environment? This allows reinfection with non-resistant parasites.