Prevention and control of communicable disease

Over the last century, infectious diseases have lost a lot of their threat to individuals’ health as well as to the health of populations living in industrialized countries. The continuous reduction and effective control of both mortality and morbidity from infectious diseases marks an impressive story of success in the history of public health in the developed world and has been linked to a wide range of improvements.

hygienic water supply, i mproved sanitation (Sanitation is the hygienic means of promoting health through prevention of human contact with the hazards of wastes as well as the treatment and proper disposal of sewage wastewater. development of antibiotics and vaccines, improved living conditions, food quality/availability, improved health care and surveillance systems have been major improvements that contributed significantly to this success.

About 2 million people die every year due to diarrhoeal diseases, most of them are children less than 5 years of age. The most affected are the populations in developing countries, living in extreme conditions of poverty, normally peri-urban dwellers or rural inhabitants.

Around 1.1 billion people globally do not have access to improved water supply sources 2.4 billion people do not have access to any type of improved sanitation facility.

Transmission control strategies and control measures: 1.Reduce contact between susceptibles and potential infectives: a) Behavior change (host and/or source), b) Case isolation, c) Case finding for intervention (e.g. isolation), d) Contact tracing for intervention (e.g. quarantine), e)Quarantine of exposed (individual, community or geographic boundary (cordon sanitaire), f) Sheltering ( isolation of nonexposed), g) Reduction in the number of infectious sources, h) Social distancing (school closures, travel restrictions)

Transmission control strategies and control measures: 2. Reduce probability potential sources are infectious: a) Case finding for intervention (e.g. isolation, treatment, etc), b) Identification and control of infectious sources, c) Vaccination

Transmission control strategies and control measures: 3. Reduced biologic susceptibility of susceptibles: a) vaccination (Pre and post exposure), b) Immune globulin (Pre and post exposure), c)Antimicrobial drug (pre and post exposure), treatment of co-factor ( e.g. Ulcerative STD

Transmission control strategies and control measures: 4. Reduce biological infectiousness of infectives: a) Treatment of cases, b) vaccination (Pre and post exposure)

Transmission control strategies and control measures: 5. Interrupt transmission between infectious source and susceptible host given contact: a)Physical and chemical methods (e.g. barriers: masks, goggles, condoms, respirators; hand sanitizers, etc. b) Engineering controls (e.g. HEPA filters, negative pressure rooms), c) Environmental controls (e.g. disinfection)

Transmission control strategies and control measures: 6. Increase herd immunity: a) Naturally-acquired immunity, b) Vaccine coverage c) Vaccine efficacy

A case of the following diseases is unusual or unexpected and may have serious public health impact, and thus shall be notified to WHO under the International Health Regulations. Smallpox, Poliomyelitis due to wild-typepoliovirus, Human influenza caused by a new Subtype, Severe acute Respiratory syndrome (SARS)

An event involving the following diseases shall always lead to utilization of the algorithm, because they have demonstrated the ability to cause serious public health impact and to spread rapidly internationally : Cholera, Pneumonic plague, Yellow fever, Viral haemorrhagic fevers (Ebola, Lassa, Marburg), West Nile fever, Other diseases that are of special national or regional concern, e.g. dengue fever, Rift Valley fever, and meningococcal disease.

Any event of potential international public health concern, including those of unknown causes or sources and those involving other events or diseases than those listed in the last two slides shall lead to utilization of the algorithm.

The algorithm 1- Is the public health impact of the serious? 2-Is the event unusual or unexpected? If both questions answered as yes event shall be notified to WHO under the IHRs. If the first question answered as yes, the second question answered no; then the third question is asked “Is there a significant of international spread”. If the answer is yes then event shall be notified to WHO.

If the first question answered no, then a new question is asked “ Is this event unusual or unexpected”. If the answer is yes another question is asked “is there a significant risk of international spread”. If the answer is yes the event shall be notified under the IHRs to WHO. If the last question is answere as not, a n additional questioan is asked: Is there a significant risk of international travel or trade restrictions?. İf this answere is yes the event shall be notified ounder IHRs to WHO