Communicable diseases part 1

• Communicable diseases


  Diseases that are readily transferred from one infected person to a susceptible and uninfected person and may be caused by microorganisms

  
• Communicable diseases are often the leading causes of all illness in the country today. Most often they afflict the most vulnerable, the young and the elderly. They have numerous economic, psychological, and disabling distinguishing effects to the emergence of newly discovered diseases and the re-emergence of old ones.
• Types of Microorganisms causing infections

  • Bacteria
  • Viruses
  • Fungi
  • Parasites
• Chain of Infection


  1. Etiologic agent (microorganism)

  2. Reservoir (host)

  3. Portal of exit from reservoir

  4. Mode of Transmission

  5. Portal of entry to the susceptible host

  6. Susceptible host
• Etiologic agent


  The extent to which any microorganisms is capable of producing an infectious process depends on the number of microorganism (pathogenicity), the ability of the microorganisms to enter the body, the susceptibility of the host, and the ability of microorganisms to live in the host's body
• Reservoir


  There are many reservoirs, or source of microorganisms. Common sources are the other humans, the client's own microorganism, plants, animals, or the general environment. People are the most common source of infection for others and for themselves.
• Portal of exit from the Reservoir


  Before an infection can establish itself in a host, the microorganism must leave the reservoir.
• Methods of transmission


  • Direct transmission
  • Indirect transmission (vehicle borne or vector borne)
• Direct transmission


  Involves immediate and direct transfer of microorganisms from person to person through touching, biting, kissing, or sexual intercourse.
• Indirect transmission


  May either be vehicle borne or vector borne
• Vehicle borne transmission


  A vehicle is any substance that serves as an intermediate means to transport and introducing infectious agent into susceptible host through a suitable portal of entry. Fomites (inanimate objects or materials) such as handkerchiefs, toys, soiled clothes, cooking or eating utensils, and surgical instruments or dressing can act as vehicle.
• Vector-borne transmission


  A vector is an animal or flying or crawling insects that serves as an intermediate means of transporting the infectious agents. Transmission may occur by injecting salivary gland fluid during biting or by depositing feces or other materials on the skin through the bite wound or a traumatized skin area.
• Portal of entry to the susceptible host

  Before a person can became infected, microorganisms must enter the body. The skin is a barrier to infectious agents; however, any break in the skin can readily serve as portal of entry. Often, microorganisms enter the body of the host by the same route they used to leave the source.
• Susceptible host


  A susceptible host is any person who is at risk for infection. A compromised host is a person "at increased risk", an individual who for one or more reasons is more likely than others to acquire an infection. Impairment of the body's natural defenses and a number of other factors can affect susceptibility to infection.
• Ways to break the disease cycle

  • Increasing host resistance
  • Destruction of the source and the reservoir
  • Destruction of the agent in the environment
  • Avoidance of exposure

  
• Immunization


  The process of introducing vaccine into the body to produce antibodies that will protect our body against a specific infectious agent. Most vaccine are given more than once since the first dose gives only half projection the body needs. A second shot or "booster" is needed to give the body full projection against the disease.
• Situations where immunization is recommended


  • For infants
  • Following exposure
  • For all persons in endemic areas
  • For person subject to unusual risk
  • For known cases
• Vaccines available for routine immunization

  • DPT (Diptheria, pertussis and tetanus) vaccine
  • OPV (Oral Polio Vaccine)
  • MMR (Measles, Mumps, Rubella) vaccine
  • Hib (H.influenza type B) polysaccharide vaccine
  • Hepatitis B vaccine
  • BCG (Bacillus of Calmette and Guerin)
  • CDT (Cholera, Dysentery, Typhoid)
• Chemoprophylaxis


  Administration of drugs to prevent occurrence of infection. e.g. Penicillin for gonorrhea, Chloroquine for malaria, INH for tuberculosis
• Mechanical Prophylaxis


  Placing mechanical barriers between the sources of agent and host such as use of mosquito nets, masks or gloves
• Health education of mothers, relative and attendants in the practice of strict aseptic methods of umbilical care in the newborn.
• Handwashing


  The most important procedure for preventing the transfer of microorganisms and the therefore nosocomial infection is correct and frequent handwashing.
• PPEs


  Personal Protective Equipment
• Influenza


  Highly communicable disease characterized by abrupt onset with fever which last 1 to 6 days, chilly sensation or chills, aches or pain in the back and limbs with prostrations. Respiratory symptoms include coryza, sore throat and cough.
• In the Philippines, influenza ranks 6th in the leading cause of morbidity (DOH, 2014)
• Influenza virus


  Influenza virus A,B, C
• Mode of transmission for influenza

  By direct contact, through droplet infection, or by articles freshly soiled with discharge of nose and throat of infected person, airborne
• Signs and symptoms of influenza

  • Fever
  • Chills
  • Headaches
  • Cough
  • Sore throat
  • Runny or stuffy nose

  
• Prevention and control measures for influenza

  • Observe proper personal hygiene
  • Increase your body's resistance
  • Practice social distancing
  • Active immunization with influenza vaccine provided prevailing strain of virus matches antigenic component of vaccine

  
• Treatment for influenza


  Self-limiting, take antivirals drugs if prescribed by a doctor
• Avian influenza (bird flu)


  Influenza is recognized both as emerging and re-emerging viral infection and is described as an unvarying disease caused by a varying virus. It is an infectious disease of birds ranging from mild to severe form of illness. All birds are thought to be susceptible to infection with avian influenza, though some species are more resistant than others. Some forms of bird flu infections can cause illness to humans.
• Causative agent for avian influenza

  Influenza virus A (H5N1)
• Mode of transmission for avian influenza

  Through inhalation of/or contamination with infected discharges of feces of infected bird/chicken
• Signs and symptoms of avian influenza

  • Fever
  • Body weakness and muscle pain
  • Cough
  • Sore throat
  • May have difficulty in breathing in severe cases
  • Sore eyes and/or diarrhea in some persons

  
• Control measures for avian influenza in birds

  • Rapid destruction, proper disposal of carcasses and rigorous disinfection of farms
  • Restriction on the movement of live poultry
• Preventive measures for avian influenza in humans

  • Wash hands thoroughly
  • Cook poultry produce thoroughly
  • Yearly vaccination of poultry workers with regular of periodic direct contact with poultry
• Treatment for avian influenza

  Self-limiting, antiviral drugs such as osetalmivir stop the progress of the illness if given within the first 2 days from the onset of fever
• SARS (Severe Acute Respiratory Syndrome)


  A newly recognized form of a typical pneumonia that had been described in patient in Asia, North America and Europe. The earliest known cases were identified in Guangdong Province, China in November 2002.

  
• Causative agent for SARS

  SARS Coronavirus (SARS-CoV)
• Mode of transmission for SARS

  Spread through close person-to-person contact (droplet spread)