Epidemiological Transitions Unit 1 Population VII Epidemiological Transitions

Epidemiological Transition Model ETM-within the past 200 years, virtually every country has experienced an epidemiological transition-a long-term shift in health and disease patterns. This transition from a high level of death for young people (communicable/infectious diseases) to low levels of death with death concentrated among the elderly (degenerative diseases). Therefore, the variation by age of mortality is reduced. People survive to advanced ages and then die quickly once reaching that advanced age. This transition, according to Abdel Omran (‘71), is the result of a country undergoing the process of modernization or economic development. The ETM closely parallels the DTM. ***In the past, parents buried their children; now, children bury their parents. (more developed countries). This process leads to a rectangularization of death.

STAGES OF THE ETM (Epidemiological Transition Model) Epidemics/Pandemics: Infectious and parasitic diseases, famine Ex: Black Plague (25 million Europeans died) The transition from stage 1 to stage 2 (from hunting and gathering to primary food production), allows for an increase in infectious and parasitic diseases to occur due to an increase in human contact and contact with possible vectors. This leads to a high CDR and low life expectancy. Stage 2 Receding pandemics become epidemics; (infectious diseases affects high proportion of population, but in isolation) Ex: Cholera (contaminated water supply), Latin America-leptospirosis (Weil’s Disease), Tuberculosis (see map), West Africa-Ebola (3,000 confirmed cases), Sub-Saharan Africa-Malaria, AIDS, Meningitis Epidemics are more isolated than pandemics. Thus impacts a lesser portion of the population.

Epidemiological Transition Model The transition from infectious to chronic, degenerative diseases now occurs Stage 3 (What does a doctor really cure?) Degenerative and human-created disease, infectious and parasitic diseases continue to decline, diseases Associated with aging increase as people live longer. Ex: Cardiovascular disease and Cancer Stage 4 Delayed degenerative diseases Ex: Alzheimer's, Diabetes Stage 5? Re-emerging infectious and parasitic disease Ex: Malaria, TB, AIDS What is causing Stage 5? Where is it located? What about MERS (South Korea)? Bird Flu-U.S.? Understandings about diseases…No matter the stage all countries are susceptible to certain communicable diseases on the mere basis of their most densely populated areas. This is especially true considering the level of globalization that is seen in the world today.

WHAT IMPACTS THE ABILITY OF DISEASES TO DIFFUSE? Population density and urbanization – High density equates to high rate of diffusion. Over 50% of the global population lives in urban areas. With more people living in dense conditions, there is more frequent contact between more individuals, allowing disease transmission to easily occur. (Contagious Diffusion) Migration and global travel –. (Relocation Diffusion) Environmental degradation –especially common in vector borne diseases (Zika Virus) All of the above factors will influence the rate of diffusion OR … ***R0-R Nought-average number of people who will contract the disease from one contagious person. This rate of transmission does not include vaccinated people. Any R Nought number greater than one could potentially lead to an epidemic. Example: 1918 Swine Flu (R Nought of 2.6-killed 50 million people “Pandemic”)

Regionalizing Diseases Sub-Saharan Africa- South America- South Asia- East Asia Russia and Surrounding States-

The World’s Deadliest Infectious Diseases

AIDS/HIV+ 2010 world distribution: 23 million in Sub-Saharan Africa 5+ million in Asia (India, China, SE Asia) 2 million in Latin America (Caribbean-Haiti) Sub-Saharan Africa 70% of HIV cases Zimbabwe, Botswana, Zambia, South Africa, Kenya Increased death rates Declining life expectancy

New Disease: The Zika Virus symptoms of Zika virus- fever, rash, joint pain, or conjunctivitis (red eyes). Symptoms typically begin 2 to 7 days after being bitten by an infected mosquito. Pregnant mothers can transmit virus to baby and baby could possibly be born with extremely undersized head.

Rectangularization of Death Mortality rates declining, more people surviving to an advanced age due access to medicine and medical care.