Lecture 4- Whipworms & Capillaria

What is the common name for Trichuris vulpis?

Canine Whipworm

Describe the morphology of Trichuris vulpis.

Small worms with whip-like anterior ends, ~30-50mm long, females always larger, tiny buccal capsule with a long esophagus (~2/3 of body length).

What is the life cycle type of Trichuris vulpis?

direct life cycle

How are Trichuris vulpis eggs passed in feces?

Eggs are passed unembryonated

How long does it take for Trichuris vulpis eggs to become infective?

approximately 3 weeks

How do dogs become infected with Trichuris vulpis?

by ingestion of larvated eggs

Where do Trichuris vulpis larvae migrate and develop in the host?

They hatch beneath the intestinal lining and migrate to the large intestine.

Where are adult Trichuris vulpis worms found in the host?

Lower bowel and cecum.

How long is the prepatent period (PI) for Trichuris vulpis?

Approximately 3 months (90 days).

What is the national prevalence of Trichuris vulpis in the U.S.?

0.41%

Which regions have the highest proportion of infected animals?

middle and eastern united states

What is the prevalence of Trichuris vulpis in Tennessee (TN)?

0.90%

What percentage of dogs in a local shelter may be infected with Trichuris vulpis?

~30%

What are common signs and symptoms of Trichuris vulpis infection in sick animals?

Dysorexia, weakness, weight loss, intermittent vomiting, diarrhea.

What type of diarrhea is associated with severe Trichuris vulpis infections?

Fluid brown diarrhea with mucus and flecks of red blood.

What factors contribute to Trichuris vulpis disease?

Large numbers of worms acquired from hyper-contaminated environments.

What are common locations where Trichuris vulpis contamination occurs?

Kennels, dog runs, small enclosed yards, pet parks, and places that allow egg accumulation.

Why are contaminated environments hazardous for Trichuris vulpis transmission?

They allow the accumulation of infective eggs, increasing the risk of infection.

How does Trichuris vulpis affect the intestinal epithelium?

It burrows into the intestinal lining, causing cellular inflammation, eosinophilic infiltration, edema, and fibrosis in the colon.

What are the physiological consequences of Trichuris vulpis infection?

Fluid secretion, decreased absorption, diarrhea, nutrient loss, electrolyte imbalances, and small blood loss at attachment sites.

What electrolyte imbalances are associated with Trichuris vulpis infection?

Hyponatremia, hyperkalemia, and a decreased sodium/potassium ratio.

What condition can Trichuris vulpis mimic due to electrolyte imbalances?

Pseudo-Addison's disease.

What diagnostic test is used to detect Trichuris vulpis?

fecal flotation

What are the characteristics of Trichuris vulpis eggs?

Large eggs (~90x40μm) with polar plugs.

What is the treatment protocol for Trichuris vulpis using Fenbendazole (Panacur)?

50 mg/kg SID for 3 days.

What is the treatment dose for Febantel (Drontal +)?

25 mg/kg SID.

What is the monthly prevention dose of Milbemycin (Interceptor)?

500 µg/kg.

What is the monthly prevention dose of Moxidectin (Advantage Multi)?

2.5 mg/kg.

How can environmental contamination be reduced to prevent Trichuris vulpis?

Remove feces daily and move the dog run if possible.

What is the role of monthly "suppressive" treatment in Trichuris vulpis prevention?

It reduces environmental contamination by limiting egg accumulation.

What measures can be taken to limit exposure at pet parks?

Avoid contaminated areas and use chemoprophylaxis with effective drugs.

What is another name for clinical trichuriasis?

Pseudo-Addison's disease.

What causes cellular inflammation, eosinophilic infiltration, edema, and fibrosis in the colon in trichuriasis?

Burrowing of Trichuris vulpis worms into the intestinal epithelium.

What are the physiological effects of Trichuris vulpis infection?

Fluid secretion, decreased absorption, diarrhea, nutrient loss, and electrolyte imbalances.

What type of blood loss is associated with Trichuris vulpis infection?

Small blood loss at the worm attachment sites.

What electrolyte imbalances are seen in clinical trichuriasis?

Hyponatremia and hyperkalemia.

What happens to the sodium/potassium ratio in Trichuris vulpis infection?

it decreases

What is the general morphology of Capillaria spp.?

Small worms with whip-like anterior ends.

How does Capillaria spp. compare in size to Trichuris spp.?

Capillaria spp. resemble Trichuris but are smaller.

Which classes of vertebrates can be infected by Capillaria spp.?

Fish, amphibians, reptiles, birds, and mammals.

How many species of Capillaria are known?

over 250 species

What percentage of Capillaria species have been studied in detail?

Less than 10%.

What are the three types of life cycles seen in Capillaria spp.?

Simple direct, facultative indirect with a paratenic host, and obligate indirect with an intermediate host.

What is a simple direct life cycle in Capillaria spp.?

A life cycle where the parasite develops without the need for an intermediate host.

What is a facultative indirect life cycle in Capillaria spp.?

A life cycle where a paratenic host may be involved, but is not required for transmission.

What is an obligate indirect life cycle in Capillaria spp.?

A life cycle that requires an intermediate host for development and transmission.

How do Capillaria spp. eggs compare to Trichuris vulpis eggs?

They are smaller (~65μm), may have off-set polar plugs, and exhibit different surface textures.

What surface textures can Capillaria spp. eggs have?

Smooth, micropunctate, or rugulate.

What is the significance of Capillaria spp. in companion animals and livestock?

They have minor significance.

In which industry is Capillaria spp. a significant concern?

Poultry production.

Which Capillaria species affects the alimentary tract/intestine?

Capillaria (Aonchotheca) puttori (affects cats and mustelids).

Which Capillaria species affect the respiratory tract/sinuses?

Capillaria (Eucoleus) boehmi and C. aerophilus.

Which Capillaria species affect the urinary tract/bladder?

Capillaria (Pearsononema) plica and C. feliscati.

Which Capillaria species have zoonotic significance?

Capillaria hepatica and Capillaria philippinensis.

What is the common name for Trichinella sp.?

Trichina worm.

How large are Trichinella sp. males?

1.4 to 1.6 mm.

How large are Trichinella sp. females?

3 to 4 mm.

What is a distinguishing feature of the Trichinella sp. esophagus?

It is long and approximately equal to the rest of the body length.

What type of life cycle does Trichinella sp. have?

Direct life cycle.

Where in the host does Trichinella sp. reside?

Small intestine of a wide variety of mammals, including humans.

Where do Trichinella sp. larvae encyst?

In the tissue of the definitive host.

How are Trichinella sp. larvae transmitted to a new host?

Through ingestion of encysted larvae in poorly cooked meat.

How quickly do Trichinella sp. larvae develop into adults and mate after ingestion?

within 2 days

What happens after Trichinella sp. females become gravid?

They migrate into the intestinal mucosa and pass larvae that encyst in tissues.

Is Trichinella sp. a zoonotic disease?

Yes, it is a zoonotic disease that affects humans.

What type of meat has Trichinella sp. traditionally been associated with?

Pork from infected domestic swine.

Why has the risk of Trichinella sp. infection from pork decreased?

Due to total confinement-based swine production.

How has the number of Trichinella sp. cases changed over time?

It has steadily declined.

What was the median number of Trichinella sp. cases and deaths annually from 1947-1951?

393 cases annually with 57 deaths.

What was the median number of Trichinella sp. cases annually from 1997-2001?

12 cases annually with no deaths.

How many Trichinella sp. cases were reported in 2016?

26 cases

How many Trichinella sp. cases were reported in 2017 by August 11?

5 cases

What is the most common source of Trichinella sp. infections today?

Wild game, particularly bear meat.

How is Trichinella sp. diagnosed?

By clinical signs, history, serology, and isolation of the agent.