Parasitic Pathogens Flashcards
Describe the life cycle of common pathogenic protozoa, especially the sporozoa
Trophozoite: feeding and dividing stage
Cyst - dormant but infectious stage
Sexual reproduction - via conjugation or gametogenesis
Asexual reproduction - fission or schizogeny(multiple mitosis of nuclei folllowed by cytoplasmic segmentation: 1 cells to many)
Define intermediate host and definite host
Intermediate: host where larva lives (asexual reproduction)
Definite: host where adult lives (sexual reproduction)
List the common pathogenic protozoa, the diseases they cause and their modes of transportation
Sporozoa (intracellular, no motility, transmitted fecal, oral) - malaria, toxoplasmosis, sryptosporidium = diarrhea (main symptom of aids)
Amoeba (in water fecal, oral) - Amoebiasis, amoebie meningoencephalitis
Flagellates (sexually transmitted)
- Luminal (in reproductive or intestinal tract) - trichomonas vaginalis, no cyst stage
- Hemoflagellates (lives in blood stream, transmitted by insect bite) - Sleep Sickness, Chagas diseas, Leishmaniasis
Ciliates (lives in colon, luminal) - causes diarrhea
Compare in general terms the life cycle of nematodes and platyhelminths
Nematode - sexual
Platyhelminths - hermaphrodites or sexual
Helminth Transmission
Intermediate host (pigs) - ingestion of larvage in tissue of another host
Fecal-oral - accidental ingestion of eggs or larvae from feces of infected host
Active skin penetration - larval stages invade through skin
Injection by insect - larval stages develop to infectivity in sect intermediate host
Intestinal and Tissue infections by helminths
INTESTINAL
nematode - eggs leave through feces, larva hatch in wild, get eaten and develop in intestines
Tapeworms - adult in human intestine, larva in animal muscles (pigs cattle)
TISSUE INFECTION
Blood Fluke - definitive host: human blood. int host: snail
Liver fluke - def. human liver, int host: fish, snails
