Emerging and Reemerging Infectious Disease
Innate Immunity
A form of defense common to all animals that is active immediately upon exposure to pathogens and that is the same whether or not the pathogen has been encountered previously.
General Transmission
Abiotic environmental factors, animal vectors
Modes of Infectious Disease Transmission
Direct Contact Indirect Contact Droplets Airborne Fecal-Oral
Agent factors that contribute to reemerging infectious disease
Evolution of pathogenic infectious agents Development of resistance to drugs Resistance of vectors to pesticides Virulence-degree to which agent is able to cause disease
Host factors that contribute to reemerging infectious disease
Human demographic change (inhabiting new areas) Human behavior (sexual & drug use) Human susceptibility to infection (Immunosuppression) Poverty & social inequality
Natural immunity (Active)
Immunity due to exposure to a pathogen that has entered the body (example acquiring measles)
Reemerging
Infectious agents that have been known for some time, but rates had fallen to such low levels that they were no longer considered public health problems & are now showing upward trends in incidence or prevalence worldwide
Dracunculiasis (Guinea Worm Disease)
Is likely to be eradicated soon Control is a reduced incidence Elimination is controlled in a certain geographic area incidence near zero Eradication is worldwide incidence zero
Animal Vectors
Mosquitoes (malaria, dengue) Fleas (bubonic plague)
Emeriging
Newly identified & previously unknown infectious agents that cause public health problems either locally or internationally
Foodborne-infected food, toxins in food
Norovirus, Salmonellosis, Hep A E Coli, Trichinosis, botulism
Abiotic Environmental Factors
Rocks, wind, water, temperature, inhalation of spores, entry into skin.
Populations at risk
Very young or old Immunosuppressed High-risk lifestyles Healthcare workers International travelers
Vector borne
carrier (Malaria, Lyme, West Nile, Zika, Rocky Mountain)
Incubation Period
is the time from invasion to the time when disease symptoms first appear. Frequently the communicable period begins before symptoms are present.
Airborne via droplet
measles, variola, TB, pertussis, influenza. SARS
Airborne
occurs through contact with contaminated respiratory droplets spread by a cough or sneeze Pathogens aerosolized and stay infective Eg: Influenza, Tuberculosis
Indirect Contact
refers to situations in which a susceptible person is infected by contact with a contaminated surface Pathogen survives harsh environment Picks up pathogen from surface or air Eg: Influenza, Norovirus
Fecal-Oral
spread of disease via eating, drinking, or licking food, water, or objects contaminated by feces Through contaminated water or food Eg: Cholera, Norovirus, Shigella
Herd immunity
the resistance to the spread of a contagious disease within a population that results if a sufficiently high proportion of individuals are immune to the disease, especially through vaccination.
Droplet
transmission via airborne droplets less than 1 meter pathogen are in droplets but do not survive long this way Eg: Ebola , bordetella pertussis
Artificial Immunity (Active)
vaccination, exposure to antigen, stimulates memory response (example tetanus vaccine to stimulate production of antibodies to tetanus)
Role of Nurse
• Immunizations: tracking, education, administration. • Communicable disease surveillance-data collection and analysis. • Teach and monitor blood borne pathogen control. • Advise on prevention of vector borne diseases. • Educate on responsible sexual behavior and screen for STIs. • Screen for TB, identify TB contacts, and deliver directly observed TB treatment, evaluate teaching and compliance. • Help develop public health policy. • Surveillance to investigate and track origin of disease. • Reporting diseases mandated to the state.
Direct contact
host to host (Sexually transmitted, mo to infant Mono, Impetigo, lice, scabies)
Adaptive Immunity
immunity or resistance to a specific pathogen; slower to respond, has memory component
Artificial Immunity (Passive)
injecting immune serum from virus patient, attempt to neutralize the threat, immunotherapy, no immunological memory (example injection of tetanus antitoxin to an unimmunized person
Latent Period
An infectious agent that has invaded a host and found conditions hospitable will replicate until it can be shed from the host. This period of replication before shedding
Natural Immunity (Passive)
Antibodies pass from mother to fetus via placenta or to infant in the mother's milk (example infant born with temporary antibodies to measles)
Waterborne-fecal contamination
Cholera, Typhoid fever, Dysentery, Giardia
Environment factors that contribute to reemerging infectious disease
Climate & changing ecosystems Economic development & Land use (urbanization, deforestation) Technology & industry (food processing & handling) International travel & commerce Breakdown of public health measures (war, unrest, overcrowding) Deterioration in surveillance systems (lack of political will)
Direct Contact
exposure or transmission of a communicable disease from one person to another by physical contact Pathogen survives best inside body EG: HIV , Herpesviruses, Ebola