ruminant internal parasites- the HOT complex- unit 3

common name for Haemonchus contortus, Haemonchus placei, Haemonchus similis

Haemonchus spp

common name for Haemonchus contortus

barber-pole worm

what species does Haemonchus contortus affect?

sheep

common name for Haemonchus placei

wireworm

what species does Haemonchus placei affect?

cattle

what is the common name for Haemonchus similis?

stomach worm

what species does Haemonchus similis affect?

cattle, sheep, goats

phylum/ class of Haemonchus spp

Nemathelminthes- nematode

location of Haemonchus spp

abomasum (the true stomach, glandular)

what species does Haemonchus spp affect

ruminants (especially sheep/lambs)

Haemonchus spp life cycle

adult worm passes egg, eggs pass into environment (pasture), larvae hatch from eggs, larvae mature into infective L3 larvae (cannot overwinter- they die), infective L3 larvae are ingested on pasture (infective L3 larvae mature into adults in abomasum- they don’t travel)

can Haemonchus spp overwinter?

no

pathogenesis for Haemonchus spp

adults and L4 larvae suck blood (very bad in lambs)

clinical signs of Haemonchus spp

weight loss, weakness, pale mm, submaxillary edema (decrease oncotic pressure; fluid build up under mandible) (called “bottle jaw”) there isn’t enough blood to carry O2

diagnosis of Haemonchus spp

strongyle-type egg, quantitative fecal results (EPG counts)

• 3,000 EPG= light infection

• 10,000 EPG= typical infection

• 30,000 EPG= heavy infection (should medicate)

Baermann (discover what type), CBC: anemia, hypoproteinemia

treatment for Haemonchus spp

supportive care (vascular support- colloids), anthelmintics if indicated (deworm): fenbendazole, albendazole, levamisole, ivermectin, doramectin

control for Haemonchus spp

proper nutrition, pasture management (rotational grazing), genetic selection

economic impact for Haemonchus spp

low protein= decrease in: protein, milk, breeding ability, wool production

can Haemonchus spp be reverible?

yes, if caught early enough

what is a FAMACHA score card?

used to determine when to deworm and what to use, it’s an eyelid score card, helps determine whether to treat the animal or not, saves money on tx costs, decreases drug resistance, encourages improved genetics related to immunity, used all over the world

common name for Ostertagia ostertagii, Ostertagia (Teladorsagia- new name) circumcincta, Ostertagia trifurcate

Ostertagia spp

common name for Ostertagia ostertagii

brown stomach worm

what species does Ostertagia osteragii affect?

cattle

common name for Ostertagia (Teladorsagia) circumcincta

brown stomach worm

what species does Ostertagia (Teladorsagia) circumcincta affect?

sheep and goats

what species doe Ostertagia trifurcate affect?

sheep

phylum/class for OStertagia spp

Nemathelminthes- nematoda

location of Ostertagia spp

abomasum

what species does Ostertagia spp affect?

ruminants (more reports in cattle)

life cycle of Ostertagia spp

same as Haemonchus EXCEPT: Ostertagia larvae can overwinter(survive winter in grass), can go through hypobiosis (arrested stage of development in larvae- encyst and pop out later)

what is hypobiosis?

arrested development of the larvae, location: mucosa of the abomasum- destroys the glands, North US: occurs during winter, South US: occurs during the summer

pathogenesis of Ostertagia spp (important)

do not suck blood- but cause epithelial cytolysis (busts up epithelial cells) as they leave the muscosa, chronic abomasitis= permanent destruction, L3 infective larvae enter the lumen of gastric glands in the abomasum, destroy glands= less HC1(hydrochloric acid) production, decreased digestion occurs

clinical signs of Ostertagia spp

weight loss, poor weight gain, decreased appetite, diarrhea

diagnosis of Ostertagia spp

fecal float: strongyle-type eggs

Baermann to ID larvae

treatment for Ostertagia spp

strategic deworming (reports of resistance to ivermectin, note: levamisole is not approved for female dairy cattle)

economic impact Ostertagia spp has

once affected, always affected, damage done to abomasum is irreversible, you will never get what you had hoped for from sheep/cattle affected by Ostertagia spp., high worm burden= poor doer for life

control for Ostertagia spp

rest pastures, rotate pastures, decrease total number of livestock on pasture, improve genetic

common name for Trichostrongylus axei and Trichostrongylus colubriformis

Trichostrongylus spp

common name for Trichostrongylus axei

stomach hair worm- abomasum

what species does Trichostrongylus axei affect?

cattle, sheep, goats

location of Trichostrongylus axei

abomasum

location of Trichostrongylus colubriformis

small intestine

what species does Trichostrongylus colubriformis affect?

cattle, sheep, goats

phylum/class of Trichostrongylus spp

Nemathelminthes- nematoda

location of Trichostrongylus spp

abomasum and small intestine (the only of the 3 in the HOT complex found in the SI as well)

what species does Trichostrongylus spp affect?

ruminants

life cycle for Trichostrongylus spp

the same as Haemonchus EXCEPT: DO go through hypobiosis, L3 infective larvae DO overwinter on pasture

does Trichostrongylus spp go through hypobiosis?

yes

does Trichostrongylus spp overwinter?

yes

pathogenesis for Trichostrongylus spp

does not suck blood, cause moderate to severe abomasitis (decreases function of gastric glands- similar to Ostertagia)

clinical signs of Trichostrongylus spp

not bad unless large worm burden. weight loss, watery diarrhea, dingle berries, death

diagnosis of Trichostrongylus spp

fecal float: strongyle-type egg

Baermann: ID the larvae

treatment for Trichostrongylus spp

strategic deworming

control for Trichostrongylus spp

proper nutrition

economic impact of Trichostrongylus spp

not usually too bad unless high worm burden or in conjunction with the HOT COMPLEX

what is the HOT COMPLEX?

H= Haemonchus - sucks blood

O= Ostertagia- permanent damage to abomasum

T= Trichostrongylus- permanent damage to abomasum

when the 3 abomasal nematodes are put together, what do they cause?

a synergistic effect- they’re worse together than they would be if they were each on their own