6. Anriparasitic drugs Flashcards
Charasteristic of parasitic diseases?
Usually chronic, undetected, and contribute to nutritional deficiency
Mention & explain 2 type of parasite hosts!
- Primary (definitive) host: where the parasite matures & if possible reproduces sexually
- Intermediate host: Where the parasites are still immature or in asexual form
Difference between obligate & facultative parasite?
Obligate: needs to infect host to complete life cycle.
Facultative: Doesn’t need to infect host to complete life cycle.
What are the classification of parasites?
- Protozoan
2. Animalia
What are the classification of parasites?
- Protozoan
2. Animalia
Mention & explain types of Protozoan parasites!
- Flagellates – whip like flagella
- Amoeboids – pseudopodia /protoplasmic flow to move
- Sporozoa – non motile
- Ciliates – cilia around its body
What are 3 common protozoan parasite infection?
Trichomoniasis, giardiasis, amebiasis
Explain the fecal-oral life cycle/route of infection of intestinal protozoa!
Intestinal protozoa has 2 form: the cyst and trophozoite; where the trophozoite is the vegetative form, in a feeding state, motile (can move), and can replicate. When the trophozoite is exposed to billiary secretion, some will undergo encystment to form a cyst (dormant/resting state) which has quite strong resistance to harsh environment. The cyst will pass through the feces out to environment. Infection can happen (e.g. not washing hands that has cyst) and once cyst enter host, it will undergo excystation into trophozoite form.
2 type of animalia parasite?
Helminths & Arthropod
What is the attachment structure of helminths that let it stick to walls of intestine?
hook
2 types of helminths? Exlplain!
- nemathelminths (roundworm): intestinal parasite, non-hermaphroditic
- platyhelminths (flat worms): hermaphroditic, there is 2 type: Trematodes/ Fluke
(flattened & leaf shaped)
and Cestodes / Tapeworm (flat, ribbon like segments (proglottids)
containing male and
female reproductive
structures)
Explain complexity of parasitic diseases!
- has many form through out lifecycle (drug need to be able to affect all form to eradicate)
- parasite has the ability to disrupt, evade, & inactivate host’s immune
- can develop drug resistance (occurs often in plasmodium)
- No effective vaccine against any human parasitic infection
- Paracite – Host – Environment factors (hard to eradicate paracite forms that are already in environment)
- Vector transmitting parasites have developed insecticide resistance (has occured with mosquito)
- Harmful effect of infection
Mechanisms of Disruption, Evasion, Inactivation of Host Defense ?
- Antigenic variation
- Molecular mimicry: produce antigens that mimic host antigens
- Masking: acquire host molecules that conceal the antigenic site
- Intracellular location: hiding, preventing being ‘detected’
- Immunosuppression: Suppressing parasite specific immune cells, degradation of Ig
How parasite damage cell/tissue?
- Toxic parasite products (destructive enzymes, amebic ionophore, endotoxins)
- Mechanical tissue damage (migration through tissue, Pressure atrophy, Blockage of internal organs->worms in digestive system/
elephantiasis by filariasis) - Immunopathological reactions (Anaphylactic, Cytotoxic, Immune complex, Cell-mediated)
What are sources infection of parasite?
- Contaminated soil and water
- Freshwater
- Crab and crayfishes
- Fishes
- Raw or undercooked pork
- Raw or undercooked beef
- Watercress
- Blood-sucking insects
- Dogs & cat
- Fly
