TOPIC 9

• 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, disabling and distinguishing effects to the emergence of newly discovered diseases and the re-emergence of old ones.
• Communicable diseases


  Readily transferred from one infected person to a susceptible and uninfected person and maybe caused by microorganisms

  
• Types of Microorganism 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.
• Method 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.
• Disease cycle


  1. Increasing host resistance

  2. Destruction of the source and the reservoir

  3. Destruction of the agent in the environment

  4. Avoidance of exposure

  
• Specific Protection against Disease

  • Immunization
  • Chemoprophylaxis
  • Mechanical Prophylaxis

  
• Immunization


  The process of introducing vaccine into the body to produce antibodies that will protect our body against a specific infectious agent.
• Immunization against communicable disease


  • For infants
  • Following exposure
  • For all persons in endemic areas
  • For person subject to unusual risk
  • For known cases
• Vaccine 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.
• Mechanical Prophylaxis


  Placing mechanical barriers between the sources of agent and host such as use of mosquito nets, masks or gloves

  
• The most important procedure for preventing the transfer of microorganisms and the therefore nosocomial infection is correct and frequent handwashing.
• PPEs (Personal Protective Equipment) are used for protection against diseases.
• 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)

  
• Causative agent of Influenza

  • Influenza virus A,B, C
• Signs and symptoms of Influenza


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

  
• Prevention and Control of 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 of 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 of Avian Influenza

  Influenza virus A (H5N1)

  
• 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 Measure for Avian Influenza in Birds

  • Rapid destruction
  • Proper disposal of carcasses
  • Rigorous disinfection of farms
  • Restriction on the movement of live poultry

  
• Preventive Measure 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 of 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)


  It is 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. The WHO issued the global alert on the outbreak on March 2003 and instituted worldwide surveillance.

  
• Causative agent of SARS

  SARS Coronavirus (SARS-CoV)
• Mode of Transmission of SARS

  Spread through close person-to-person contact (droplet spread)
• Signs and Symptoms of SARS

  • Prodormal phase: Body temperature of more than 38 C sometimes with chill, malaise and headache. During this stage the infectivity is none or low.
  • Respiratory phase: Within 2 to 7 days the illness may proceed to this stage characterized by dry nonproductive cough with or without respir