ruminant

Question 1

What are treatment options based on?

Answer 1

economics, production systems, increasing evidence of anthelmintic resistance

Question 2

What is hypobiosis?

Answer 2

inhibited, arrested, or latent larvae. Under certain conditions larvae undergo this in abomasal or intestinal wall and emerge later, molt, and mature

Question 3

What are common characteristics?

Answer 3

Most life cycles are direct, oviparous females, eggs hatch and molt in environment, L3 on grass is most infective stage! Strongyle type eggs. L1-L2 free living on the grass

Question 4

Development of strongyle type eggs

Answer 4

Depends on temperature and moisture. Dessication kills eggs and larvae and most lethal. Can develop into L3 in fecal pats. After evaporation of moisture, larvae move down the grass.

Question 5

The size of GI nematodes depend on

Answer 5

number of infective L3, rate at which resistance develops, intrinsic multiplication rates, management, use of anthelmintics

Question 6

20-30% of the herd carry…

Answer 6

80% of the parasites

Question 7

Goals of parasite control

Answer 7

prevent heavy infections in susceptible hosts, reduce levels of pasture contamination, encourage development of immunity in herd

Question 8

What is the HOT complex?

Answer 8

Haemonchus, ostertagia, trichostrongylus; adults in the abomasum. PPP is about 3 weeks!

Question 9

Haemonchosis

Answer 9

Haemonchus contortus. Lancet/tooth in buccal cavity, cervical papillae, males have asymmetrical bursal ray, females look like barber pole. L3s embedded in abomasum, molt to L4, return to feed in abomasum. In lambs, very pathogenic. Post parturient immunosuppression most common for large infections. DIARRHEA IS NOT COMMON. Bottle jaw.

Question 10

Treatment for Haemonchus

Answer 10

Benzimidazoles (white dewormer), macrocyclic lactones. Oral drench or put in feed

Question 11

What is FAMACHA program?

Answer 11

For Haemonchus, resistance common in small ruminants. Leave others not treated so they shed low numbers of eggs-refugia. If have to be treated multiple times, kill. Also known as RESISTANCE, REFUGIA, HERD GENETICS MANAGEMENT. based on clinical anemia.

Question 12

Ostertagiasis

Answer 12

Ostertagia ostertagi, most economically important helminth parasite, smaller than haemonchus, no asymmetrical dorsal ray, females have small vulvar flap. Penetrate gastric glands, L3 may winter over pasture. Leads to decreased acid production, profound changes of gastric mucosa. Emergence of adult associated with marked cellular changes that are triggered by worm antigens. ANOREXIA.

Question 13

What is Type 1 ostertagiasis?

Answer 13

no hypobiosis, recent infection of L3 in northern areas, fecal egg counts high

Question 14

Pre-type 2 ostertagiasis

Answer 14

as fall occurs in north, increasing number of larvae do not undergo immediate development to adults, become arrested as L4 in gastric glands of abomasum

Question 15

Type 2 ostertagiasis

Answer 15

Emergence of large numbers of inhibited L4 that were ingested as L3 but were hypobiotic; spring in north. In cattle. Low fecal egg counts.

Question 16

Treatment of Ostertagiasis

Answer 16

Strategic deworming when numbers on pasture are low.

Question 17

Trichostrongylosis

Answer 17

Males have unequal spicules, females have cervical notch, abomasum or small intestine. asymptomatic until high numbers.

Question 18

Cooperia

Answer 18

Small intestine, now most prevalent in cattle.Cuticle forms cephalic swelling. Transverse ridges in cuticle. Female has small flap in middle of body. Hypobiosis follows ostertagia. Over winters on pasture. Destroys villi, may show small white lesions. Can be a problem in lightweight cattle. Tolerance to macrocyclic lactones.

Question 19

Nematodirus

Answer 19

Small intestine. Males have paired spicules. Female is amphidelphic, cephalic swelling. Molts to L3 inside egg., L1/L2 protected by egg shell on pasture. No inhibited stage. Cause inflammation. Diarrhea in calves, immunity occurs rapidly. no ivermectin. high survival rate.

Question 20

What’s the main criteria for keeping refugia?

Answer 20

Don’t deworm calves older than 3 years.

Question 21

Bunostomum phlebotomum

Answer 21

Small worms, large buccal cavity, chitinous plates. small intestine. Suck blood, hemorrhages on mucosa. Mostly southern states.

Question 22

Strongyloides papillosus

Answer 22

Intestinal threadworm. Small intestine. Only females are parasitic. Larvated eggs. Tracheal and somatic migration. Infective stage is L3 via penetration. Transmammary. Cause blood in diarrhea. Treat with macrolides.

Question 23

Trichuris

Answer 23

egg contains L1 ingested. Rip and shred mucosa. Anemia may have ascites. Fenbendazole.

Question 24

Oesophagostomum

Answer 24

Pimply gut. Shallow buccal capsule, cephalic inflations of cuticle. Feces attached to female tail. LArvae penetrate intestinal wall and form nodules, re emerge and travel to colon. Chronic infections have nodules but no adults.