Soil-transmitted Helminths Flashcards
Pathogenic Agent:
Pinworm
Enterobius Vermicularis
- Small threadlike white worms
- Females migrate at NIGHT to lay eggs
Population most affected by pinworms?
- Children under 18
- Those taking care of them
Person to person:
Pinworm
Yes.
Person-to-person
(Hands, toys, bedding)
Transmission Mechanism:
Pinworm
- Eggs ingested
- Larvae hatch in intestines and migrate to colon to mature
- Adults pooped out and lay eggs on perianus
- Anus is scratched
Clinical Finding:
Pinworms
Perianal itching
Diagnosis:
Pinworms
Scotch tape swab (3 mornings after they wake before washing)
Treatment (Drugs):
Pinworms
- Mebendazole/Albendazole
- Pyrantel
- Ivermectin
- Levamisole
- Piperazine
What is the most common worm in the United States?
Pinworms
Common intestinal infection of the cecum - large intestine
Pathogenic Agent:
Ascaris
Ascaris limbricoides
- Long white yellow worms
- Liv in jejunum or ileum (small intestine not colon)
Where does ascaris live in the body?
Jejunum or ileum (small intestine)
Distribution:
Ascaris
Tropics, part of Europe, warm, humid areas in warmer months
Person-to-person:
Ascaris
No direct person-to-person transmission
Clinical Findings:
Ascaris
- Asymptomatic but mild abdonimal discomfort
- Children with heavy burden are obstructed and can’t digest protein
(Spaghetti noodles)
Ascaris in children leads to malabsorption of what?
- Fat, lactose, vitamin A
Due to impaired digestion of protein
What is the most common worm infection in the world?
Ascaris (most asymptomatic)
Pathogenic Agent:
Whipworm
Trichuris trichiura
Distribution (general):
Whipworms
- Areas where human feces used as fertilizer
Person-to-person:
Whipworms
No person-to-person transmission
Clinical Findings:
Whipeworm
- Asymptomatic
- Intestinal - diarrhea, nutritional deficiencies, rectal prolapse, painful stools?
Rectal prolapse is seen with which worm?
- Whipworm
Diagnosis:
Whipworm
- Eggs in stool
- Adult worms on prolapsed rectum or colonoscopy
Clubbing of nails from anemia is common with which worm?
Whipworm
Treatment (drugs):
Whipworm
Albendazole
Ivermectin
Pathogenic Agent:
Hookworm
- Necator Americanus
- Ancylostoma duodenale
- Small white worms that live in intestines for 5 years and lay 7000 eggs daily ( caan drain 0.03ml of blood a day per worm so high burden means a lot of blood loss)
Transmission Mechanism:
Hookworm
- Eggs pooped in stool to soil and larvae hatch
- Larvae penetrate skin in contact with soil
- Circulate to lungs
- Penetrate alveolar wall and climb trachea
- Swallowed to intestines
Clinical Findings:
Hookworms
- Asymptomatic
- “Ground itch”
- Loeffler syndrome - cough after the hookworms reach the lungs
- Yellow disease
“Ground itch” is associated with which worm?
Hookworm
Loeffler syndrome? What is it and it’s association?
Cough. Associated with hookworms reaching the lungs
Diagnosis:
Hookworms
Stool examination
Treatment (drugs):
Hookworms
- Albendazole
- Levamisole
- Pyrantel
Prevention:
Hookworms
Walking with shoes
What worm is the major cause of iron deficiency?
Hookworms
Pathogenic Agent:
Strongyloides
S. stercoralis
Rhabditiform larvae
Distribution:
Strongyloides
Tropical and subtropical regions
- Kentucky most common parasitic infection
Most common parasitic infection in Kentucky?
Strongyloides
Transmission (general):
Strongyloides
Direct cutaneous or musosal penetration
Can strongyloides be passed in breastfeeding?
Yes
Clinical Findings:
Strongyloides
Immunocompetent person - Asymptomatic
Immunocompromised perosn - severe disease
Organs: GI tract, lung, skin, pulmonary
Bacteremia or gram negative sepsis (after they invade blood stream
Diagnosis:
Strongyloides
Detection of rhabditiform larvae in stool
Detection of filariform larvae in stool or sputum
Sputum stronger evidence for hyper infection
Small bowel biopsy less useful
Molecular methods like ELISA (IgG) does not distinguish old vs new infection
True or False
Molecular methods like ELISA (IgG) does not distinguis old vs new infection
True
Treatment (drug):
Strongyloides
- Ivermectin (drug of choice)
- Thiabendazole (high failure)
- Albendazole (poor absorption)
Prevention:
Strongyloides
Hygiene
Shoes
Duration of infection with strongyloides
Lifetime
Pathogenic Agent:
Neurocysticercosis/Tapeworms
Taenia solium (
Vector:
Neurocysticercosis/Tapeworms
Infected pork
Humans obligate host
Distribution (general):
Neurocysticercosis/Tapeworms
Areas where pigs are raised close to humans
Eastern Europe, Latin America, India, Sub-saharan Africa
Clinical Findings:
Neurocysticercosis/Tapeworms
- Few symptoms but two options
Parenchymal (brain)
Extraparenchymal (outside of brain)
Clinical Findings:
Parenchymal Neurocysticercosis/Tapeworms
- Seizure and headache
- Cysticeral encephalitis
- Favorable prognosiss
- When inactive we see Ca+ spots in image
Clinical Findings:
Extraparenchymal Neurocysticercosis/Tapeworms
- Ventricles and CSF and can cause increased cranial pressure, heart attacks, dizziness, visual changes
- Ventricular - needs MRI
- Active subarachnoid space - similar to active parenchymal
- Spinal - radicular parasthesia
Which is worse parenchymal or extraparenchymal Neurocysticercosis/Tapeworms
Extraparenchymal - more fatal
Diagnosis:
Parenchymal Neurocysticercosis/Tapeworms
- Neuroimaging is the definitive test
- Serodiagnostics is poor because it crosses reactions with other parasites
Treatments (drugs):
Parenchymal Neurocysticercosis/Tapeworms
- Antiepileptics
- Praziquantel - treatment of choice
- Albendazole
- Niclosamide
- Ventricular - open craniotomy or endoscopic surgery
- Subarachnoid - no treatment
- Spinal - surgery
- Ocular - surgical resection
Prevention:
Parenchymal Neurocysticercosis/Tapeworms
Sanitation, less pig contact + vaccines
Pathogenic Agent:
Echinococcus
Echinococcus granulosus
- small
Vector:
Echinococcus
- Dogs (definitive host)
- Sheeps, cattle
Distribution:
Echinococcus
Everywhere
- Most common in people raising sheeps (which eat plants contaminated by dogs)
Phase:
Echinococcus
- Eggs travel to lungs and liver to make fluid filled cyst
- When large enough they cause discomfort and vomiting (can get big enough to cause physical destruction of affected organs)
Clinical Findings:
Echinococcus
- Asymptomatic
- Slow growing cyst in liver, lungs, and other organs
- Alveolar echinococcusis- most sever form with high mortality because of metastatic cyst (treated with “Find and watch” method
Diagnosis:
Echinococcus
- Imaging techniques (CT, ultrasound, MRI)
- Serology to confirm
Treatment:
Echinococcus
- “Watch and wait” - conservative approach
- Surgery - remove
- PAIR (percutaneous aspiratin injection of chemicals and reaspiration)
- Chemotherapy with albendazole
Prevention:
Echinococcus
- Stop dogs from eating infected sheep carcasses
- Control stray dog population
- Washing hands
