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