(LE4) Helminth Pathogens

Question 1

What kingdom do helminths fall in to?

Answer 1

Animalia

Question 2

What are parasitic specializations of helminth pathogens?

Answer 2

• degenerative digestive, nervous, and muscular systems
• live in constant environment, no complex structures

Question 3

What disease is shown here? What causes this disease? Describe the mode of transmission, signs/symptoms, prevention and treatment, and interesting facts

Answer 3

Disease: Bilharzia (Schistosomiasis)

Pathogen: Schistosoma mansoni (Trematode)

MOT: waterborne

S/S: swollen abdomen (inflammation around eggs), fever, malaise, fatigue

Tx: 1 dose; Praziqunatel

Question 4

Describe the lifecycle of Schistosoma mansoni

Answer 4

Eggs released in feces and urine-> hatch into miracidia-> infect snails (intermediate host) -> release cercaria larvae and burrow into human skin -> adults in Hepatic portal vein and lay eggs -> egg movement to gut and urine bladder

Question 5

What disease is shown here? What causes this disease? Describe the mode of transmission, signs/symptoms, prevention and treatment, and interesting facts

Answer 5

Disease: Tapeworm

Pathogen: Taenia saginata (beef), Taenia solium (pork) (cestoda)

MOT: Foodborne, (eggs can contaminate water)

S/S: - usually asymptomatic
- weight loss, diarrhea, nausea, vomiting, GI pain

Tx: Surgical removal

ETC: - Proglottids, larvae, or eggs are all infectious
- Cysticercosis: Taenia in the brain (seizures, blindness, deafness, paralysis). Praziquantel can kill worm but not fix symptoms

Question 6

What disease is shown here? What causes this disease? Describe the mode of transmission, signs/symptoms, prevention and treatment, and interesting facts

Answer 6

Disease: River blindness

Pathogen: Oncocerca volvulus (Nematode)

MOT: vectorborne (biting blackfly). Lives near fast-flowing streams and rivers. Transmits larvae

S/S: Nodule at bite site. Progression to lymphatic system to the eye can cause blindness

Tx: Ivermectin (2 doses/year -> prevention)

Question 7

What disease is shown here? What causes this disease? Describe the mode of transmission, signs/symptoms, prevention and treatment, and interesting facts

Answer 7

Disease: Pinworm

Pathogen: Enterobius vermicularis (nematode)

MOT: Fecal-oral route (ingestion of eggs)

S/S: Night-time perianal itching

Tx: Albenza or Vermox 2 doses 2 weeks apart (only kills larval stages

ETC: most common in US

Question 8

What disease is shown here? What causes this disease? Describe the mode of transmission, signs/symptoms, prevention and treatment, and interesting facts

Answer 8

Disease: Hookworm

Pathogen: Necator americanus (nematode)

MOT: Fomite (eggs passed in stool, hatch in soil, larvae penetrate skin

S/S: Anemia

Tx: Albenza or Vermox (1-3 days)

ETC: - attach to the intestinal wall and drink blood

Question 9

What disease is shown here? What causes this disease? Describe the mode of transmission, signs/symptoms, prevention and treatment, and interesting facts

Answer 9

Disease: Trichinosis

Pathogen: Trichinella spiralis (nematode)

MOT: Foodborne (undercooked pork)

S/S: Muscle pain, little spots of blood under fingernails

Tx: more difficult to treat, but usually Albenza or Vermox

ETC: Larvae encyst in striated muscle

Question 10

What disease is shown here? What causes this disease? Describe the mode of transmission, signs/symptoms, prevention and treatment, and interesting facts

Answer 10

Disease: Ascariasis

Pathogen: Ascaris lumbricoides (nematode)

MOT: Oral-fecal

S/S: Ascaris pneumonia, Large accumulation leads to intestinal blockage

Treatment: Albenza or Vermox (1-3 days), surgical removal

ETC: - most common in the world
- juvenile worms end up in lungs. adult worms in small intestines
- eggs laid in intestines