Airborne & Vector Flashcards
Entry and development or multiplication of agent in the host
Infection
Chain of Infection
- Infectious agent
- Host
- Environment
- Transmission process
Factors determining the nature of infection
Pathogenicity Virulence Infective dose Reservoir Source
Ability of an agent to produce disease
of persons with clinical illness/ # of persons exposed
Pathogenicity
A measure of the severity of the disease
Virulence
Amt required to cause infection in a susceptible host
Infective dose
Natural habitat of the agent; may be human, animal, or environmental
Reservoir
Person, animal or object from which the host acquires the agent
Source
Carrier
Infected person who shows no evidence of clinical disease
- duration of carrier state : may be a few days to several years
- asymptomatic
- spread of disease
Person or animal that provides a suitable place for the infectious agent to grow and multiply under natural conditions
HOST
- point of entry: eyes, nose, ears, mouth, skin
- incubation period
- consequences depend on host’s resistance
- vaccines & antibodies: dengue ( 4x - kasi diff strains), measles, chicken pox
Direct modes of transmission
Touching
Kissing
Sex
Others- childbirth, medical procedures, injection of drugs, breastfeeding
Airborne- shortdistance, via droplets, coughing, sneezing
Blood transfusion
Transplacental
Transfusion
Transplacental
Indirect modes of transmission
- vehicle borne ( cont food, water, towels, farm tools, etc )
- vector borne ( anthropods, rats, snails )
- airborne, long distance ( dust, droplets )
- parenteral ( inj w/ cont syringe )
Transmission from one generation to another in the same generation
Horizontal transmission
from parent to offspring, such as perinatal transmission
Vertical transmission
Routes of transmission
Respiratory Vehicle borne Sex Oral Iatrogenic
Transmission by any medical professional
Iatrogenic
Any (inanimate) object capable of carrying an infectious agent
Fomite
Fecal-oral routes
Cholera Hepa A Polio Rotavirus Salmonella Intestinal parasites
Dengue, chicungunya
Aedes mosquito
Malaria
Anopheles
Japanese encephalitis, lymphatic filariasis
Culex
Lyme disease
Ticks
Chaga’s
Triatomine bugs
Schistosomiasis
Aquatic snails
Factors that influence transmission
Globalization of travel and trade
Unplanned urbanization
Environmental changes
Climate change
