Intro Prt 2 Flashcards
SPECIAL TYPES OF INFECTION
- Autoinfection
- Hyperinfection or Superinfection
Infected individual becomes his own direct source of infection
Autoinfection
Ex. Enterobiasis through hand-to-mouth transmission - In enterobiasis, infection may occur through hand-to-mouth transmission.
Infective eggs may end up in the hands by scratching the perianal areas where the gravid females lay their eggs.
Autoinfection
Infected individual is further infected with same species leading to massive infection
Hyperinfection or Superinfection
Ex. Capillaria philippinensis, Strongyloides stercoralis -
An alteration in the normal life cycle of Strongyloides results in a large increase in worm burden, which may lead to severe debilitation or even death due to an increase in the proportion of rhabditiform larvae that transform into filariform larvae while in the gut.
Hyperinfection or Superinfection
Female adult worms can be OVIPAROUS or LARVIPAROUS
Hyperinfection
Superinfection
There are no males in the parasitic portion of the life-cycle.
parasitic
(parthenogenetic)
_______adult female worm undergo_______meaning, the adult female worm produces embryonated eggs even in the absence of an adult male worm, even if thereis no fertilization.
Strongyloides stercoralis
parthenogenesis
The egg may hatch even inside the intestine liberating rhabdiliform larva that may also further develops to become filariform larva this filariform nerve penetrates the intestinal mucosa or perianal skin and migrate back to the small intestine to become an adult worm. This cycle repeats again and again and again resulting to________.
hyperinfection
AGENTS OF TRANSMISSION
Vehicle/ Fomites
Vector
AGENTS OF TRANSMISSION
•: non-living entity
•: living entity
Vehicle or Fomites
Vector
transports pathogens plus plays a role in the life cvcle of pathogen
Biological Vector
While carrying and transporting the organism develops further or even reproduces inside the vector
Biological Vector
(Malaria inside mosquito)
Biological vector
organism that only transports a pathogen
Mechanical Vector
(Flies, cockroaches that feed on fecal material with parasites)
Mechanical vector
MODES OF TRANSMISSION
PPACISB
Peroral
Percutaneous
Arthropod vector
Congenital transmission
Inhalation of Airborne eggs
Sexual intercourse
Blood-borne transmission
MODE OF TRANSMISSION
(Contaminated Food and Water): MC source; majority of cestodes, trematodes and intestinal protozoans like amoeba
Peroral
MODE OF TRANSMISSION
hookworm, strongyloides, schistosoma
Percutaneous (Skin Penetration)
MODE OF TRANSMISSION
: malaria, filaria, leishmania, trypanosoma
Arthropod Vector
MODE OF TRANSMISSION
toxoplasma (transplacental), ancylostoma and strongyloides (transmammary)
Congenital
Transmission
MODE OF TRANSMISSION
: enterobius
Inhalation of Airborne Eggs
MODE OF TRANSMISSION
: Trichomona vaginalis, giardia, entamoeba
Sexual Intercourse
MODES OF TRANSMISSION
: malaria
Blood-borne Transmission