Infectious Disease Prevention and Control

historical perspective

-in the US, at the beginning of the 20th century, infectious diseases were the leading cause of death

-improvements in nutrition, sanitation, the discovery of antibiotics, and development of vaccines put an end to common infectious disease epidemics

-leading cause of death in 2021: heart disease

financial impact of infectious disease

-worldwide, infectious diseases are the leading killer of children and are responsible for almost half of all deaths in low income countries

-majority of deaths result from acute lower respiratory infections/pnuemonia, diarrheal diseases, TB, HIV, and malaria

infectivity

the ability to enter and multiple in the host

pathogenicity

the ability to produce a specific clinical reaction after infection occurs

violence

the ability to produce a severe pathological reaction (how sick it will make an individual)

toxicity

the ability to produce a poisonous reaction (toxins that are produce, shigella)

invasiveness

the ability to penetrate and spread throughout tissue

antigenicity

the ability to stimulate and immunological response

resistance

the ability of a host to withstand infection (may involve natural or acquired immunity)

natural immunity

species-determined, innate resistance to an infectious agent (oppossums and rabies)

acquired immunity

the resistance acquired by a host as a result of previous natural infection (childhood chickenpox)

active immunization

the immunization of an individual by the admin of an antigen which creates an antibody response in host

passive immunity

immunization through the transfer of a specific individual to a non-immunized individual (maternal transfer)

herd immunity

the immunity of a group or community which creates resistance to infection

infectiousness

the measure of the potential ability or an infected host to transmit the infection to other hosts

vertical transmission

the infection from parents to offspring via sperm, placenta, milk, or contact in the vaginal canal

horizontal transmission

person-to-person spread of infection

common vehicle

transportation of an infectious agents through food, water, saliva, droplets in air

vectors

living organisms that can transmit infectious pathogens between humans or from animals to humans

disease development

exposure to an infectious agent doesn’t always lead to infection

-infection doesn’t always lead to disease

infection

refers to the entry, development, and multiplication of the infectious agent. inthe susceptible host

disease

one of the possible outcomes of infection, damages cells and results in s/s of illness

incubation period

the time interval between invasion by the infectious agents and the first appearance of s/s of disease

communicable period (contagious)

the interval during which an infection agent may be transferred directly. or indirectly from an infected person to another person

disease spectrum

infected individuals may exhibit a broad spectrum of disease that ranges from subclinical to severe and fatal disease

-it is important of prioritize subclinical infections from an individual standpoint for early diagnosis and treatment to minimize complications and maximize prognosis, but also from a public health standpoint to prevent transmission

endemic

the constant presence of disease within a geographic area or population

epidemic

the occurrence of disease in a community of region in excess of normal expectancy

pandemic

an epidemic occurring worldwide and affecting large populations (COVID, H1N1, Zika, HIV)

surveillance of communicable disease

-surveillance gathers the “who, when, where, and what”; these elements are then used to answer “why”

-surveillance systems collect, organize, and analyze current, accurate, and complete data for a defined disease condition

-the results of surveillance are used to effectively plan, implement, and evaluate disease prevention and control

-passive system: NEDSS

-active system: CDC workers

-sentinel system: community monitoring sites

-healthcare workers are mandated by state law to report any Nationally notifiable conditions

emergining infectious diseases

-those diseases in which the incidence has actually increase in the past several decades or has the potential to increase in the near future

-several factors, operating singly or in combination, influence the mergence of disease

-microbial adaptations, changing environmental temps, habitat changes

-rise in household with 2 working parents has increase number of children in daycare

-changing sexual behaviors

-large air-conditioning systems

-modern transportation

-insects. andanimals

elimination

removes a disease from a large geographic area such as a country or region of the world

eradication

removes a disease worldwide by ending all transmission of infection through the complete examination of the infectious agent

primary prevention

-responsible sexual behavior

-malaria chemoprophylaxis

-tetanus booster, flu shot

-safe handling food practices

-regulated and inspected water supplies

-federal regulation protecting against exposure to BSE

secondary prevention

-immunoglobulin after hep A exposure

-immunization and chemoprophylaxis as appropriate in meningococcal outbreak

-rabies post-exposure immunization

-tuberculosis screening for health care workers

-STD partner notification

-HIV testing and treatment

-quarantine

tertiary prevention

-PCP chemoprophylaxis for ppl with AIDs

-regular inspection of hands and feets and protective footwear for pts with leprosy

multisystem approach to communicable disease prevention

-illness from communicable diseae represents an imbalance in the host-environment-agent relationship, any apporach to controlling infection must consider multiple systems, including enhancing host resistance, improving safety of the environment, strengthening public health systems, and facilitating social and political changes

anthrax

perpetuates itself by forming spores

smallpox

eradicated since 1979, 100% susceptibility in unvaccinated,fatality, rate 20-40% viral stock exist in CDC and research facilities

plague

responsible for killing over a quarter of a population in Europe during the Middle Ages

vaccine

one of the most effective methods of preventing and controlling communicable diseases

measles

rubeola virus, highly contagious

-spread by inhalation of aerosolized droplets or by direct contact with infected nose/throat secretions

-most ppl are contagious before they are aware

-s/s: fever, sneezing, coughing, conjuctivitis, white spots inside of cheek/Kopliks spots, red blotchy rash beginning several days after resp. signs

pertussis

whooping cough, highly contagious and endemic in the US

-vaccine used for prevention, immunity wanes over time and mild infection can result

-antibiotics must be given as soon as possible or not effective

-tends to have cyclical patterns wtih periodici outbreaks, nurses need to be aware

influenza

viral respiratory tract infection that is often indistinguishable from the common cold or other resp. diseases

-transmission is airborne and through direct contact with droplets

-vaccine effectiveness 68% effective at preventing pediatric hospitalization and 35% in seniors this season

food and waterborne diseases

-norovirus: leading cause of viral gastroenteritis

-salmonella: bacterial infection from eating undercooked meat

-shiga toxin-producing E.Coli: food contaminated by feces

-hepatitis A: stool accidentally contaminates food/water

-cryptosporidium parvum: improperly treated water

diseases of travelers

-individuals traveling outside of the US need to be aware of and take precautions against potential diseases (malaria, hepatitis, cholera)

-Public health travel clinics provide meds to prep for travel

-always ask pt about recent travel if they have a communicable disease

rabies

transmitted to humans via a bite or scratch from virus-carrying saliva

-essentially 100% fatality

-wild animals: raccoons, skunks, foxes, coyotes, bats

-vaccination of animals remains greatest protection

parasite disease

-worms, protozoa, ticks, fleas, lice, mites

-prevalent in rural areas and low-income countries

-contributing factors:

• tropical climate

• inadequate prevention

• poor sanitation

• lack of cheap and effective drugs

• scarcity in funding

healthcare associated infection

-caused by surgical site infections, CAUTI, clostridium difficile

-infection control strategies remain necessary

-universal precautions