Hookworms & Whipworms Flashcards
What is the hookworm superfamily?
Strongyloidea
Hookworm characteristics:
Length?
Site?
Lifecycle?
Infective stage?
Climate?
- 1-3 cm long
- S.I. predilection site
- Direct life cycle
- L3 infective stage
- important human pathogen in the tropics
Ancylostoma Caninum affects which species?
Dogs
Ancylostoma braziliense affects which species?
dogs/ cats
Ancylostoma tubaeforme affects which species?
cats
What is the lifecycle of Ancylostoma caninum & its PPP?
- Eggs in feces
- L1 moults to L3 (infective) in 5 days under optimal conditions
- L3 is sheated (retains the cuticle) to allow survival in the environment.
- Sheathed L3 can be ingested or percutaenously migrated through skin (paw pads)
- If percutaneously absorbed will migrate to the lungs and either arrest in tissues or travel to the bronchi/ trache and moult to L4 there.
- If ingested can either travel directly to the S.I. or absorbed via the buccal mucosa and travel to the lungs where they can arrest in the tissues or migrate to the bronchi/ trachea and moult to L4.
- Once in the bronchi/ trachea and in the L4 phase it will be coughed up and swallowed to the S.I.
- L4 will moult to adult in the S.I and produce eggs.
- PPP 14-21 days.
A. caninum and ALD
Larvae that migrate via the lungs can arrest as L3 in skeletal muscle.
**No transplacental infection. **
**Transmammary is important. **
Transmammary infection
btich can infect 3 consecutive litters
reactivatin L3 can prouce patent infection in bitch.
**NO TRANSPLACENTAL TRANSFER **
A. caninum pathogenesis
What level of maturity are the worms which are feeding?
Hookworm is disease is a simple hemorrhage
Immature and adult worms feed
Worms change feeding sites up to 6 times per day and each previous site fed on continuse to bleed due to production of an anticoagulant enzyme therefore causing major hemorrhage in the animal.
Hookworms bury their head in the mucosa of the S.I. and produce lytic factor, anti coagulants, and various **proteases that degrade hemoglobin. **
What clinical signs will an animal show when infected with A. caninum?
Hemorrhagic anemia, Pale MM, blood in the stool
Multiple infections will cause a hypersensitivity reaction in the skin.
A. Caninum epidemiology:
Acquired immunity?
Climate?
Three sources of infection?
Age & acquired immunity occurs therefore disease is less frequent and severe in older animals
Hookworms prefer warmer climates
- Transmammary
- Percutaneously from environment
- Oral ingested from environment
A. caninum diagnosis
Based the diagnosis off of :
- Clinical signs
- Eggs in the feces (FEC) however even if no eggs in the feces doesn’t mean there is no infection. Juvenille adults which are not sexually mature to produce eggs are still able to feed and be pathogenic thereby causing clinical symptoms (anemia) without presentation of eggs in the feces.
A caninum control
Benzimidazoles
Ivermectin
High dose of fenbendzole in pregnant bitch.
Ancylostoma excretory secretory products
Secrete anti coagulants
Secrete proteases that break down Hb in a **host specific manner. Enzyme from dog hookworm is more effective vs. dog Hb than human Hb and vice versa. **
Vaccination against hookworms: how does it work?
Antigens are isolated from the membrane of the hookworm gut.
Immunization provokes an antibody response
Hookworms feed on blood containing antibodies to the gut antigens.
Antibodies bind to the surface of the microvillar surface of the gut and inhibits digestion of the blood thereby starving the worms, they become less fecund, shorter and reduce anemia.
