hookworms, strongyles

What superfamily do hookworms belong to?

Ancylostomatidae

Which genera are considered hookworms?

Ancylostoma spp. and Uncinaria spp.

Where are hookworms found in the host?

Small intestine attached to lumen

What are the key morphological features of hookworms?

Bent anterior end, large buccal capsule, teeth or cutting plates

Which animals are commonly infected with hookworms?

Dogs and cats

Are hookworms zoonotic?

Yes, some species are zoonotic

What type of life cycle do hookworms have?

Direct life cycle

How does Ancylostoma spp. differ from Uncinaria spp.?

-Ancylostoma has teeth, large blood loss quantities, dark red worms, 2-4week PPP

-Uncinaria has cutting plates, little blood loss, pale worms, oral ingestion only, 15 day PPP

Which hosts are infected by Ancylostoma spp.?

Dogs, cats, and wild canids

Are Ancylostoma spp. blood feeders?

Yes

What is the prepatent period of Ancylostoma spp.?

2-4 weeks

What is the characteristic appearance of hookworm eggs?

Morula stage with 4-8 cells

What happens to larvae after oral ingestion of Ancylostoma caninum?

Develop in small intestine; some undergo pulmonary tracheal migration

What is the migration route after skin penetration by A. caninum?

Pulmonary-tracheal migration PRIOR to maturation in small intestine

What happens during transmammary transmission of A. caninum?

Direct development of adults in small intestine

What is somatic migration in A. caninum?

Larvae arrest in tissues

What is larval leak?

reactivation of larva, migrate to intestine, leads to continuous reinfection in dogs

What is the main cause of disease from A. caninum?

Blood feeding leading to anemia

Which age group is most severely affected by A. caninum?

Puppies

How many clinical disease forms does A. caninum cause?

Four

What is pre-acute hookworm disease?

-nursing pups via transmammary infection

-severe blood loss, sudden deterioration, dark tarry feces

Why are eggs not seen in pre-acute disease?

Infection is prepatent

What characterizes acute hookworm disease?

-older puppies or dogs with heavy infections

-patent infection, with egg shedding

-weakness, lethargy, pale MM, rough hair coat, soft to liquid, dark, tarry feces, anemia

What is chronic hookworm disease?

-occurs without signs

-weakness, emaciation, anemia

-diagnosis: hookworm eggs in feces, reduced PCV

What causes secondary hookworm disease?

-older animals with malnutrition or other diseased and secondary hookworm disease

-edema, production of anticoagulants

What is the most important preventive measure for hookworms?

Remove feces promptly

Which drugs are used to treat hookworms?

Fenbendazole, pyrantel, moxidectin

Why are post-treatment fecal exams recommended?

Drug resistance and larval leak

Which hookworm causes cutaneous larval migrans in humans?

Ancylostoma braziliense

Which hookworm can cause eosinophilic enteritis in humans?

Ancylostoma caninum

What is another name for Trichostrongyles?

Hair, wire, or thread-necked worms

Which animals are primarily affected by Trichostrongyles?

Grazing ruminants

Where are Trichostrongyles found in the host?

Abomasum and small intestine

What is a key feature of Trichostrongyle buccal capsules?

Small or absent

What life cycle do Trichostrongyles have?

Direct life cycle

How are Trichostrongyle species identified?

Male bursa and spicules

Which Trichostrongyles infect the abomasum?

Haemonchus, Ostertagia, Teladorsagia, Marshallagia, T. axei

Which Trichostrongyles infect the small intestine?

Nematodirus, Cooperia, Trichostrongylus

Why are subclinical infections economically important?

Poor feed efficiency and weight loss

What is the self-cure phenomenon?

Sudden expulsion of adult worms following ingestion of a large number of L3 stage larva

What is premunition?

Resistance due to low-level chronic infection

What is the periparturient rise (PPR)?

Increased egg shedding around parturition

What causes the periparturient rise?

Hormonal and nutritional stress

Where is Ostertagia ostertagi found?

Abomasum of cattle

Why is Ostertagia ostertagi important in the US?

Most significant helminth of cattle

What is ostertagiasis?

Disease caused by Ostertagia infection

What happens to the abomasal pH in ostertagiasis?

Becomes neutral

What are clinical signs of ostertagiasis?

Diarrhea, anemia, emaciation

Why is Haemonchus contortus called the barber pole worm?

Spiraled uterus and intestine

What feeding behavior makes H. contortus dangerous?

Voracious blood feeding

What are major effects of Haemonchus infection?

Anemia and hypoproteinemia

What is bottle jaw caused by?

Protein loss

What is the FAMACHA system used for?

Assess anemia and deworm selectively

Which animals are affected by strongyles?

Horses

What are the large strongyle species?

Strongylus vulgaris, S. edentatus, S. equinus

What are small strongyles also called?

Cyathostomes

What type of life cycle do strongyles have?

Direct life cycle

Which strongyles are more common in horses?

Small strongyles

Why are large strongyles dangerous?

Larval migration damages arteries

What artery is commonly affected by large strongyles?

Cranial mesenteric artery

What clinical signs result from strongyle migration?

Colic, thromboembolism, infarction

Why are small strongyles clinically important?

Encysted larval emergence

What is larval cyathostominosis?

Mass emergence of encysted larvae

What are signs of cyathostominosis?

Diarrhea, weight loss, anemia, edema

what are necropsy findings of acute ancylostoma canium?

-hemorrhagic enteritis

-pale internal organs

-watery blood

-edema