Control of Communicable/ Non-Communicable Diseases

1. Control of Communicable/ Non-Communicable Diseases Lecture 13 Global health affects everyone – disease knows no borders

2. CLASSIFYING DISEASES • Acute Diseases • Acute diseases are those conditions in which the peak severity of symptoms occurs within three months (usually sooner), and recovery in those who survive is usually complete • Chronic Diseases • Chronic diseases or conditions are those in which symptoms continue longer than three months and in some cases for the remainder of the person’s life. Recovery is slow and sometimes incomplete.

3. Communicable (Infectious) Diseases • Diseases for which biological agents or their products are the cause and which are transmissible from one individual to another • The disease process begins when the causative agent is able to lodge and grow or reproduce within the body • The process of lodgment and growth of a microorganism or virus in the host is termed infection • Non-communicable (Noninfectious) Diseases/Illnessses • Those diseases or illnesses that cannot be transmitted from an infected person to a susceptible, healthy one • Several, or even many, factors may contribute to the development of a given non-communicable health condition • The contributing factors may be genetic, environmental, or behavioral in nature

4. Classification of DiseasesTypes of Diseases_____Examples______________ • Acute Diseases • Communicable Common cold, pneumonia, mumps, measles, pertussis, typhoid fever, flu • Non-communicable Appendicitis, poisoning, trauma (e.g., (incl. trauma) due to automobile accidents, fires, etc.) • Chronic Diseases • Communicable Lyme disease, tuberculosis, AIDS, rheumatic fever following streptococcal infections, herpes • Non-communicable Diabetes, coronary heart disease, osteoarthritis, cirrhosis of the liver dur to alcoholism, hyptertension

5. MODES OF COMMUNICABLE DISEASE TRANSMISSION • Direct Transmission • Indirect Transmission

6. DIRECT TRANSMISSION • Immediate transfer of the disease agent by direct contact between the infected and the susceptible individuals • Examples of diseases for which transmission is usually direct are AIDS, syphilis, gonorrhea, and the common cold

7. INDIRECT TRANSMISSION • May be one of three types: air-borne, vehicle-borne, or vector-borne • Air-borne transmission-- transmission of microbial aerosols to a suitable port of entry, usually the respiratory tract. • Microbial aerosols are suspensions of dust or droplet nuclei made up wholly or in part by microorganisms -- may be suspended and infective for long periods of time • Examples of air-borne diseases include tuberculosis, influenza, histoplasmosis, and legionellosis

8. Vehicle-borne transmission -- contaminated materials or objects (fomites) serve as vehicles, nonliving objects by which communicable agents are transferred to a susceptible host • The agent may or may not have multiplied or developed on the vehicle • Examples of vehicles include toys, handkerchiefs, soiled clothes, bedding, food service utensils, and surgical instruments • Also considered vehicles are water, milk, food (e.g., common vehicles), or biological products such as blood, serum, plasma, organs and tissues • Almost any disease can be transmitted by vehicles, including those for which the primary mode of transmission is direct, such as dysentery and hepatitis

9. Vector-borne transmission -- disease transfer by a living organism, such as a mosquito, fly, or tick • Transmission may be mechanical, via the contaminated mouth parts or feet of the vector, or biological, involving multiplication or developmental changes of the agent in the vector before transmission occurs

10. DISEASE AND INJURY PREVENTION AND CONTROL • Prevention • Includes individual, clinical, or personal health services such as immunizations, screening for high blood pressure and follow-up services, or the use of Pap smears to detect the precursors to cancer of the cervix • Protection • Includes the activities of organizations, both public and private, to reduce exposure to hazards such as polluted water, contaminated food, traffic accidents, mosquitoes, or use of electric saws without safety devices

11. PREVENTION OF COMMUNICABLE DISEASES • Primary Prevention • In the chain of infection model, primary prevention strategies are evident at each link of the chain • Successful application of each strategy can be seen as weakening the link -- with the ultimate goal of interrupting the disease transmission cycle • Community measures -- e.g., chlorination of the water supply, inspection of restaurants, immunization programs that reach all citizens, maintenance of a well-functioning sewer system, proper disposal of solid waste, and control of vectors and rodents

12. Personal/Individual actions-- hand washing, proper cooking of foods, adequate clothing and housing, obtaining all of the available immunizations against specific diseases

13. PREVENTION OF COMMUNICABLE DISEASES • Secondary Prevention • Community effortincludes measures taken to control or limit the extend of a disease outbreak/epidemic -- e.g., maintaining records of cases and compliance with regulations requiring the reporting of notifiable diseases, investigating cases and contacts, those who may have become infected through contact with cases • Individual effortincludes either (1) self-diagnosis and self-treatment with nonprescription medications or home remedies, or (2) diagnosis and treatment with an antibiotic or other physician-prescribed medicine

14. Occasionally, secondary disease control measures may include isolation or quarantime • Isolation= separation, for the period of communicability, of infected persons or animals from others so as to prevent the direct or indirect transmission of the communicable agent to a susceptible person/host • Quarantine= limitation of the freedom of movement of well persons or animals that have been exposed to a communicable disease until the incubation period has passed

15. Further measures may include disinfection -- the killing of communicable agents outside the the host, and mass treatment with antibiotics • Public health education and health promotion should also be used as both primary and secondary preventive measures

16. Tertiary Prevention • Convalescence from infection, recovery to full or partial health, and return to normal activity. • In some cases, such as paralytic polio, return to normal activity may not be possible, even with extensive physical therapy. • At the community level, proper removal of infected items such as clothing, disinfection, and burial of the dead

17. Tertiary prevention may also involve the reapplication of primary and secondary measures to prevent further cases -- e.g., in Japan and South Korea, people with colds or flu wear gauze masks in public to reduce the spread of the disease

18. TOOLS AVAILABLE TO THE “STATE” FOR THE CONTROL OF COMMUNICABLE DISEASE • REPORTING-- Physicians and other health professionals must report specified diseases to a designated authority, usually to local or state health authority • LABORATORY REPORTING-- In many states, licensed laboratories must report positive results for certain diseases to the health department, even though a diagnosis may not have been established • SURVEILLANCE -- The systematic measurement of health status and risk factors • MONITORING -- Involves the ongoing assessment of a condition after intervention has been initiated

19. LABORATORY ANALYSIS -- Involves public health laboratories with authority for the study and detection of infectious diseases • CONTACT INVESTIGATION -- Once a case of a particular disease has been diagnosed, personnel from the health department are authorized to interview the victim to establish a list of possible contact. (A practice of considerable debate recently because of AIDS.)

20. TREATMENT-- Public health agencies are required to provide treatment services for specified infectious diseases. • Local health departments are also required to provide services for people infected with sexually transmitted diseases or tuberculosis. These services are not regarded as welfare services but rather as tools to prevent the spread of dangerous communicable diseases.

21. ISOLATION -- Means separation of infected people from non-infected people during the period of communicability. Follows the “least restrictive” principle • IMMUNIZATION -- All states have requirements for the immunization of children against certain infectious diseases -- most common are diphtheria, pertussis (whooping cough), tetanus, rubella (German measles), and polio. The controlling agency is usually the school system, which is required to prevent entry of any child who has not been properly immunized

22. INVESTIGATION-- health departments are required to investigate unusual occurrences of disease or injury. • This includes the authority to review medical records, • to perform laboratory investigations, • to examine patients, and • to interview both patients and others who may have been exposed to the disease or injury. (The public health authorities may require court authorization to undertake these investigations.)