Lecture 3: Parasitic Nematodes of Humans (4/15) Flashcards
(9 cards)
Neglected tropical diseases (NTDs)
Most prevalent infections of the poor, over 1 billion infected worldwide. Considered NTDs if there are many people infected but not much funding
DALY
Disability adjusted life years
Definitive/final host
The species within which the nematode parasite reaches sexual maturity and reproduces. An obligate host in the life cycle
An example of a non-definitive host would be one that only has its juvenile life cycle in humans, like Anisakis
Intermediate host
A host species in which a nematode undergoes development but does not reach sexual maturity. An obligate host in the life cycle
Paratenic/transport host
A transport host, no development. May or may not be obligate
Some species may require a paratenic host but not a specific host species
Onchocerciasis
Common name of the disease
Scientific name of the nematode
Insect vector
Symptoms
Cause of pathology
Treatment
Population scale treatment
River blindness
Onchocerca volvulus
Vectored by blackflies
Symptoms: skin itching, depigmentation, thickening, eye issues
Pathology mainly due to immune reaction
Treated with Ivermectin
Mass drug administration + vector control
Ascariasis
Scientific name of the nematode
Where is it common?
Symptoms of light vs. heavy reactions
Life cycle (where does it move)
How is it diagnosed?
Treatment
Ascaris lumbricoides
Common in poor sanitation areas
Light: may be symptomless
Heavy: pain, bloating, obstruction
Migration through liver and lungs
Diagnosed via fecal exam or observing adult worms
Antihelminthics/surgery
How do microfilariae and Wolbachia contribute to symptoms in onchocerciasis?
Inflammation of skin due to cell-mediated reactions against microfiliaria and Wolbachia molecules
How does ivermectin help control onchocerciasis?
Kills microfilaria, prevents females from producing microfilaria
