Significance of Emerging and Re-Emerging Diseases
One would think that as science, technology, and overall intelligence increase the emergence, and re-emergence, of infectious disease would decrease. Unfortunately, this is not the case. As our horizons continue to spread we began opening new doors, and new opportunities, for diseases that the human race has never seen before.
As described by the Center for Disease Control and Prevention (CDC), there are a number of factors that lead to the emergence of infectious diseases, whether they are new or re-emerging. One of the most important factors in the emergence of diseases today has to do with the increase in the human population, and migration or war brining people to new populated areas. Due to the worlds economic conditions today, many people are encouraged to move from rural areas to cities. Before many diseases would become introduced in small rural areas, where the disease cannot spread as quickly or as easily. Here, it is much easier to stop a disease from turning into an epidemic. In cities however, disease spread so fast they are hard to catch early. Also, with major airports and highways coming out of these cities it is easy for one person to carry the disease to other cites, spreading the disease further through interurban transport routes. (Morse, 1995)
International commerce and travel has become highly more advanced in the past few years. Currently, a person can get from China to New York in 12 hours; that is half way across the world. This means that a person can take a disease from one city and spread it essentially anywhere in the world within 10 to 20 hours, at most. (Norris et al., 2017) This is significant given the fact that some areas would take weeks to months to reach not even a couple centuries ago. This has increased the amount of time it takes for a disease to spread significantly. This also provides an opportunity for disease known to be in other areas to spread to areas where the disease has never been seen before.
With the increase in travel comes the increase in Technology and Industry. Technology does help in ways such as health care and food production, but it also offers more opportunity for contamination. It also allows for the agent to become introduced far away from the source. An example of this is with food products. Yes, in today’s populated world it is almost necessary to make food in mass quantities, and send it out throughout the world from factories. However, this increases the chance of contaminating the food with a possible biological agent, and then spreading it many places throughout the world. Also, chemicals and preservatives that are put into these mass batches of food have the capability of mutating disease, introducing new disease, and creating antibiotic resistance in many people. (Morse, 1995)
The emergence of antibiotic resistant bacteria is a very new 21st century problem that has the capability of causing catastrophic issues for people affected. Many previous epidemics and pandemics have been eradicated due to the discovery of penicillin and other antibiotics. Before antibiotics, people would die from small infections that today don’t even seem like a big deal. Antibiotic resistance, as well as other microbial changes in disease we are not prepared for, can cause major complication for health care, as well as the human race.
One of the most frequently identified factors in the emergence of diseases involves ecological changes and agricultural development. This is especially the case when it comes to zoonotic diseases. With the development of agriculture and such, we have also become more dependent on animals. Unlike or ancient ancestors who would literally hunt for their food everyday, rather then domesticating animals in their back yards, we have become dependent on keeping animals close by for different resources and food products. As time has gone on, we have only become closer these animals. This has made it much easier for a disease to jump from one species to another. This does not always happen through direct transmission either. Depending on the disease, zoonotic diseases can be spread from direct contact, from a vector (such as ticks and mosquitos), or through food, water, and soil. (Choffnes & Relman, 2011) One of the most common examples of this is through the spread of Escherichia coli (E. coli) E. coli was transmitted to humans through domesticated cattle. People can currently contract E. coli from eating contaminated or undercooked meat, or coming in contact with the manure or cattle that have the disease. E. coli is capable of living in the intestines of healthy cattle, without showing any symptoms in the animal. However, the animal is still contagious, and the effects of the disease can be fatal in humans. It is estimated that there have been 73,000 cases of the infection and 61 deaths in the United States. (Zoonotic Diseases & Farm Animals, 2018) Disease is not always spread through farm animals however. As the human population continues to rise, humans continue to spread out to different environments across the world. This means that more people are living in areas where people have never lived before. As we spread into forests and habitats not meant for humans to live, we open doors for infectious disease to spread from species in that area to us. This was the case in the Ebola out break. Ebola was transmitted to the human race through bats West Africa. This was also the case with HIV/AIDS, which originated in chimpanzees in the Democratic Republic of Congo. As we continue to spread, and continue to urbanize, it is almost guaranteed that we will eventually be faced with another epidemic.
References
Choffnes, E. R., & Relman, D. A. (2011). The causes and impacts of neglected tropical and zoonotic diseases: Opportunities for integrated intervention strategies: Workshop summary. Washington, D.C.: National Academies Press.
L., L., J., J., Norris, S., D., . . . Clark, J. (2017, May 30). What to Expect on a Flight from the U.S. to China. Retrieved from https://www.aroundtheworldl.com/2011/08/13/what-to-expect-on-a-flight-from-the-u-s-to-china/
Morse, S. S. (1995). Factors in the Emergence of Infectious Diseases. Emerging Infectious Diseases, 1(1), 7-15. https://dx.doi.org/10.3201/eid0101.950102.
Zoonotic Diseases & Farm Animals. (n.d.). Retrieved from https://oregonvma.org/care-health/zoonotic-diseases/zoonotic-diseases-farm-animals