The first American cases of West Nile Virus were discovered in August of 1999 in New York City (NYC). Out of a population of 815,839, for the two-month period of August to September of that year, those over 70 and over 80 had by far the greatest risk: a combined 7.5% per 200K of population. Risk factors for symptoms of the disease (which many otherwise-healthy infected people never have) were a known history of : immunosuppression; hypertension; diabetes; and coronary heart disease (“Disease detectives investigate”). The first three are common among the elderly, being either the result of, or requiring, ongoing medication and monitoring. The last, being a degenerative condition, may be the most predominate.
Now consider a disease like cholera. Regardless of age, certain genetic blood-types are either more or less susceptible to it (Harris et al.,2005). It is very rare in NYC, typically being brought in by visitors from poorer communities overseas (Baker, 2011). Cholera is even rare in the modern yet still Third World city of Cairo, Egypt, my next point of comparison. Therefore epidemics in either city would likely be the result of a disaster that impacted the sewer and water distribution systems. (Cairo has the added risk of violent civil and military conflict.) Two factors affecting the 70+ elderly in Cairo and NYC are the extreme heat of their summers. Cholera, spread by infected fecal-matter mixing with drinking water, kills principally through dehydration. Those with limited mobility and who lack air conditioning will be overheated. They may also face a lack of access to clean water and timely vaccines (“Oral cholera vaccine” 2005).
As 70+ urbanites, both groups are collectively more dependent on bureaucracies.
Baker, A. (2011, February 5). Three cases of cholera are confirmed by city officials. New York Times. Retrieved from http://cityroom.blogs.nytimes.com/2011/02/05/city-confirms-three-cases-of-cholera/
Disease detectives investigate west nile virus. (n.d.). Retrieved from http://www.cdc.gov/excite/disease_detectives/national/PDF/WestNileQ&A.pdf
Global Task Force on Cholera Control, (2005). Oral cholera vaccine use in complex emergencies: What next?. Retrieved from World Health Organization website: http://www.who.int/cholera/publications/cholera_vaccines_emergencies_2005.pdf
Harris, J. B., Khan, A. I., LaRocque, R. C., Dorer, D. J., Chowdhury, F., Faruque, A. S. G., Sack, D. A., & Ryan, E. T. (2005). Blood group, immunity, and risk of infection with vibrio cholerae in an area of endemicity. Infection and Immunity, 73(11), 7422-7427. Retrieved from http://iai.asm.org/content/73/11/7422.long