Veterinary Parasitology Quiz: Cryptosporidium & Haemonchus

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Questions and Answers

What is the infective stage of Trichostrongyles that is ingested by the host?

L3 (correct)

Which of the following is a clinical sign associated with Haemonchus spp. infection?

Diarrhea

Hemorrhagic anemia (correct)

Dermatitis

Neurological signs

What is the primary method of diagnosis for Haemonchus infections?

Stool culture

FAMACHA scoring (correct)

Ultrasound examination

Blood smear analysis

What are the ideal environmental conditions for the larvae of Haemonchus spp. to thrive?

Hot and humid Signup and view all the answers

What does PPP stand for in the context of Trichostrongyle life cycles?

Pre-Patent Period Signup and view all the answers

What is the primary route of infection for Cryptosporidium spp.?

Ingestion of sporulated oocysts Signup and view all the answers

What clinical sign is most commonly associated with Cryptosporidium infection?

Profuse watery diarrhea Signup and view all the answers

During which period does oocyst shedding typically last in animals infected with Cryptosporidium spp.?

3-12 days Signup and view all the answers

Which of the following is NOT a treatment option for Cryptosporidium infection in ruminants?

Vaccination Signup and view all the answers

How can Cryptosporidium spp. infection lead to hyperinfection particularly in immunocompromised patients?

Thick-walled oocysts causing massive reinfection Signup and view all the answers

Which of the following hosts is primarily associated with C.parvum?

Calves, sheep, goats, and humans Signup and view all the answers

What method is effective for diagnosing Cryptosporidium spp. infection?

Centrifugal flotation in sugar solution Signup and view all the answers

What is the pre-patent period (PPP) for the life cycle of Cryptosporidium spp.?

2-7 days Signup and view all the answers

What is the primary location of the parasites mentioned?

Small intestine Signup and view all the answers

Which of the following clinical signs is NOT associated with the mentioned parasites?

Weight gain Signup and view all the answers

Which parasite is described as the hardest worm to kill?

Cooperia spp. Signup and view all the answers

What percentage of mortality can N.battus cause in infected sheep?

30% Signup and view all the answers

What life cycle characteristic is noted about Nematodirus spp.?

Prolonged cold periods are necessary for infectivity Signup and view all the answers

What is indicated as contributing to PGE (Parasitic Gastroenteritis)?

Larval penetration of the mucosa Signup and view all the answers

Which of the following statements is true regarding the parasites discussed?

Clinical signs from these parasites do not indicate a specific disease. Signup and view all the answers

Which tick species is known for its distinctive white dot on females and white posterior on males?

A.americanum Signup and view all the answers

What is the primary vector for Ehrlichia ruminantium?

A.maculatum Signup and view all the answers

Which tick species has a preference for large domestic animals as its host?

A.maculatum Signup and view all the answers

What clinical sign is specifically associated with A.maculatum in ruminants?

Dropping ears Signup and view all the answers

Which tick is predominantly found in Florida and Texas?

A.cajennense Signup and view all the answers

What type of mouthparts do Dermacentor species possess?

Short mouthparts Signup and view all the answers

Which of the following is a common host for A.americanum?

Humans Signup and view all the answers

What is a clinical sign associated with ticks that damage the hides of animals?

Alopecia Signup and view all the answers

What is the primary site of infection for coccidia in cattle?

Small intestine Signup and view all the answers

Which factor is NOT associated with the development of coccidiosis in cattle?

Nutritional deficiency Signup and view all the answers

What is a common clinical sign of Toxoplasma gondii in infected ruminants?

Fetal mummification Signup and view all the answers

Which treatment is utilized for managing Tritrichomonas foetus infections in cattle?

Cull infected animals Signup and view all the answers

Which of the following is a Zoonotic disease mentioned in the content?

Toxoplasma gondii Signup and view all the answers

What is the definitive host for Neospora caninum?

Domestic canids Signup and view all the answers

Which characteristic is NOT associated with ticks in the Acarina subclass?

Separation of head, thorax, and abdomen Signup and view all the answers

What is the route of infection (ROI) for Haemonchus nematodes in cattle?

Ingestion of larvae from pastures Signup and view all the answers

What is the significance of using coccidiostats in cattle before stress occurs?

To minimize clinical disease Signup and view all the answers

What clinical sign is associated with Tritrichomonas foetus infections in heifers?

Early-term abortion Signup and view all the answers

What is the primary method of diagnosis for Neospora caninum in cattle?

PCR testing Signup and view all the answers

What is the main purpose of vaccination with Toxovax for Toxoplasma gondii?

To prevent abortion Signup and view all the answers

What is a key clinical sign of coccidiosis in cattle under 2 years old?

Severe diarrhea with potential blood Signup and view all the answers

Study Notes

Ruminant Nematodes

Strongylida
- Trichostrongyloidea (Trichostrongyles)
  - Life Cycle: Direct, infective stage is the L3 larva found on pasture.
  - Prepatent Period (PPP): Approximately 3 weeks.
  - Eggs: thin shell wall, developing morula, shed in feces.
  - Haemonchus spp. (Barber Pole Worm)
    - Habitat: Abomasum
    - Environment: High humidity, warm weather
    - Adults: Known for their distinctive red/white banding ("barber pole"). Female worms contain eggs and blood.
    - Clinical Signs: Hemorrhagic anemia (blood loss), hypoproteinemia, edema (bottle jaw), weight loss, death.
    - Diagnosis: FAMACHA system - assesses anemia based on mucous membrane color.
  - Ostertagia/Teladorsagia spp.
    - Location: Small intestine
    - Clinical Signs: Do not cause a specific disease individually, but contribute to parasitic gastroenteritis (PGE) when larvae penetrate small intestinal mucosa, leading to anorexia and diarrhea.
  - Cooperia spp.
    - Environment: Worldwide
    - Clinical Signs: Immatures burrow into gut wall and can become arrested before becoming adults, but are not considered primary pathogens.
  - Nematodirus spp. (Thread-Necked Worms)
    - Life Cycle: Larvae are retained within the egg and hatch synchronously to infect susceptible lambs. Some species (N. battus, N. filicollis) require prolonged cold periods before becoming infective.
    - Location: Small intestine
    - Eggs: Significantly larger than Trichostrongyle eggs.
    - Clinical Signs: Infections are typically well-tolerated. N. battus can damage the small intestine wall lining, causing severe diarrhea and potentially high mortality.
  - Dictyocaulus spp.
    - Life Cycle: Similar to other Trichostrongyles.
    - Location: Bronchi and bronchioles, causing lung damage.
    - Clinical Signs: Coughing, dyspnea, labored breathing, and even death.

Ruminant Protozoans

Cryptosporidium spp.
- Life Cycle: Direct. Sporulated oocysts in feces are immediately infectious and damage-resistant
- Prepatent Period (PPP): 2-7 days
- Oocyst Shedding: 3-12 days (clinical signs can occur before shedding)
- Route of Infection (ROI): Fecal-oral (thick-walled oocysts). Autoinfection (thin-walled oocysts) is possible, leading to hyperinfection.
- Hosts: C. parvum in calves, sheep, goats, horses, and humans.
- Pathogenesis: Damage to intestinal or gastric epithelium as schizonts rupture.
- Clinical Signs: Diarrhea, dehydration, anorexia, weakness. Can be subclinical to severe.
- Diagnosis: Centrifugal flotation in sugar solution. May need acid-fast or fluorescent staining. Coproantigen testing available for humans and extra-label in ruminants. PCR for species differentiation.
  - Treatment: No FDA-approved drugs for ruminants. Supportive care with fluids and electrolytes.
  - Management: Isolation of affected animals, reduced stocking density, no cohousing of young and old animals. Adequate sterilization of stalls/hutches. Proper PPE
  - Zoonotic: C. parvum is zoonotic.
Eimeria spp.
- Life Cycle: Direct
- Prepatent Period (PPP): 2 weeks (16-21 days for E. bovis, 12-14 days for E. zuernii).
- Route of Infection (ROI): Fecal-oral (sporulated oocysts)
- Site of Infection (SOI): Small intestine
- Oocysts: Unsporulated - elongated/ovoid, may have a micropyle cap
- Host-Specificity: No sharing of species between different animals.
- Pathogenesis: Primary pathogens associated with coccidiosis.
- Clinical Signs: Occur in animals under 2 years old, often triggered by stress. Severe diarrhea, sometimes with blood. Winter coccidiosis (stressful conditions). Nervous coccidiosis (neurological signs; NW US after rain and cold).
- Treatment: Prophylactic coccidiostats (given before stress) in cattle: amprolium, decoquinate, monensin, lasalocid, sulfa drugs. In goats: decoquinate, monensin. In sheep: decoquinate, lasalocid, sulfaquinoxaline. Treatment of clinically ill animals includes isolation and supportive care.
- Zoonotic: None
Toxoplasma gondii
- Life Cycle: Indirect.
  - Definitive Host (DH): Felids
  - Intermediate Host (IH): All warm-blooded animals
- Route of Infection (ROI): Ingestion of sporulated oocysts from feline feces, transplacental infection, ingestion of tissue cysts.
- Pathogenesis: Tissue invasion by tachyzoites leads to inflammation. Tachyzoites can form tissue cysts in any tissue, especially muscle and neurological tissues.
- Clinical Signs: More common in transplacental and immunocompromised patients. Abortion, fetal mummification in small ruminants infected during gestation (also a potential cause of bovine abortion).
- Diagnosis:
  - Antemortem: Serology tests (not definitive)
  - Postmortem: Histopathology and PCR testing
- Treatment: No effective treatment for tissue stage elimination.
- Prevention: Avoid contamination of feed/pasture with cat feces. Vaccination (Toxovax) available in Europe and New England (prevents abortion, not infection).
- Zoonotic: Cook all animal tissues thoroughly before consumption.
Neospora caninum
- Life Cycle: Indirect.
  - Definitive Host (DH): Wild and domestic canids
  - Intermediate Host (IH): Cattle (dairy)
- Route of Infection (ROI): Ingestion of sporulated oocysts from canine feces, transplacental infection.
- Clinical Signs: Primary cause of bovine abortion (incidence peaks at 5-6 months). Surviving infected calves may have neurological deficits. Potential cause of abortion in small animals. Suspected of reducing milk production in dairy cows.
- Diagnosis:
  - Antemortem: Serology tests (serum or bulk milk; not definitive)
  - Postmortem: Histopathology and PCR testing
- Treatment: No effective treatment for tissue stage elimination.
- Prevention: Avoid feed/pasture contamination with canine feces. Don't allow canids to consume uncooked or aborted ruminant tissues.
- Zoonotic: None.

Ruminant Protozoans (Continued)

Tritrichomonas foetus (Flagellate Parasite)
- Life Cycle: Direct. Motile trophozoites in the cattle reproductive tract.
- Route of Infection (ROI): Sexually transmitted (live cover is more likely than AI). Can be transmitted through AI with contaminated semen.
- Clinical Signs: Beef cows are more susceptible than dairy cows.
  - Heifers: Mild vaginitis, breeding failure or early-term abortion (less than 3 months), pyometra.
  - Bulls: Asymptomatic chronic carriers.
- Diagnosis: Microscopic examination of male or female samples. PCR detection from samples. Sensitivity can be increased by culturing samples in Diamond's Medium before testing.
- Treatment: No effective drugs for clearing cattle, no FDA-approved drugs. Cull infected cows and bulls.
- Management: Vaccination (TrichGuard) for cows, use younger bulls, use negative-tested bulls. AI is preferred over live cover. Reduce the length of the breeding season. Cull infected cattle.
- Regulation: State laws require testing for T. foetus. In Oklahoma, for example, bulls over 12 months old, potentially exposed females, and all bulls entering the state for breeding should be tested. Testing can be done with 3 negative culture tests at weekly intervals or 1 negative PCR test.
Buxtonella sulcata (Ciliate Parasite)
- Life Cycle: Direct (two life stages):
  - Trophozoite: Motile, found in the cecum. Large in size.
  - Cyst: Passed in the feces. Kidney-shaped macronucleus.
- Route of Infection (ROI): Fecal-oral (cysts)
- Clinical Signs: Many animals are clinically normal (commensal organism). Diarrhea in weaning calves.
- Diagnosis: Identify cysts. Sedimentation and flotation with salt solution. Cysts are morphologically similar to Neobalantidium coli.
- Treatment: Rare, no FDA-approved drugs.

Ruminant Arthropods

Arachnida (Ticks and Mites)
- General Characteristics:
  - Anatomy: Fusion of the head, thorax, and abdomen.
    - Idiosoma: The main body
    - Mouthparts: Basis capitulum, palpa, chelicera, hypostome (for feeding) (long: longer than wide; short: wider than long)
  - No antennae or mandibles.
  - Adults: 4 pairs of legs.
  - Females: Larger, scutum covers only a portion of the body. This allows for engorgement and egg production. Can produce 5,000 - 10,000 eggs.
  - Males: Scutum covers the entire dorsal body.
- Life Stages: Eggs → larva → nymph → adults (male and female).
  - Larva: 6 Legs
  - Nymphs: 8 Legs
  - Adult: Genital aperture present.
- Parasitism: All are parasites, feeding on blood. Quest for hosts is influenced by temperature, humidity, and availability of hosts.
- Clinical Signs: Irritation, pruritus, secondary infections at bite wounds, anemia, transmission of disease agents (regurgitation), tick paralysis. Production loss (reduced weight gain, damage to hides).
Ticks
- Ixodidae (Hard Ticks)
  - General characteristics:
    - Anatomy: Mouthparts visible from dorsal surface. Scutum is present (complete in males, anterior in females).
    - Life Cycle: 1, 2, or 3 hosts
      - 1 host: Larvae remain on the host and become adults after 2 molts.
      - 2 host: Molting (nymph to adult) occurs in the environment.
      - 3 host: Host for each life stage. More effective at transmitting disease.
    - Diapause: Lowered metabolism and activity when conditions are unfavorable
    - Life Cycle Length: Depends on environmental conditions and host availability
  - Amblyomma spp.
    - General characteristics: Long mouthparts, ornate scutum.
    - A. americanum (Lone Star Tick)
      - Hosts: Deer, domestic animals, humans
      - Scutum: White dot for females, white along posterior for males
    - Distribution: Eastern, Central, Southeastern, South-central US
    - Clinical Signs: Damage to hides
    - Vector: Ehrlichia spp. (Most common tick in Southeastern and South-central US)
    - A. maculatum (Gulf Coast Tick)
      - Hosts: Domestic animals, preference for large animals
      - Scutum: White lace pattern
      - Distribution: Gulf Coast, Atlantic Coast
      - Clinical Signs: Damage to hides, aggressive biters, "gotch ear" in ruminants (edema, crusting and alopecia of the pinna, drooping ears)
      - Vector: Ehrlichia ruminantium
    - A. cajennense (Cayenne Tick)
      - Distribution: Florida, Texas
      - Vector: Theileria equi (to horses)
  - Dermacentor spp.
    - General characteristics: Short mouthparts, rectangular basis capitulum.
    - 3 Host Ticks
      - D. andersoni (Rocky Mountain Wood Tick)
      - D. variabilis (American Dog Tick)
      - Hosts: Domestic animals, humans
      - Vectors:
        
        Anaplasma marginale
        
        EP (Theileria equi, Babesia caballi) to horses
    - 1 Host Tick
      - D. (various species)
        
        Hosts: Various
        
        Vectors: Ehrlichia spp..

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Test your knowledge on the life cycles, clinical signs, and diagnostic methods associated with Trichostrongyles and Cryptosporidium infections in ruminants. This quiz covers critical aspects of veterinary parasitology, focusing on common parasites and their impact on animal health.