Various factors that impact EID (Emerging infectious diseases)

By Avishek Majumder & Diksha Tomer on October 9, 2018

Emerging infectious disease (EID) is a type of disease occurring from infections of unknown strains of microorganisms. They may also reoccur from infectious diseases that may have occurred many years back. These infectious diseases are either new or have the potential to become epidemic in the near future. Some common examples of the EID include; HIV/AIDS, tuberculosis, Influenza, malaria, dengue, cholera, Ebola, and many others to name (Drotman et al., 2018). However, the emergence of these diseases is caused by certain factors that have been focused on in this article.

Factors that impact EID

Factors in infectious disease emergence
Factors in infectious disease emergence

The cause of occurrence of any infectious disease depends on environmental and human factors.  Human factors include demographics, lack of awareness, and social factors. Environmental factors include climate change, natural disasters, and microbial adaptations and resistance. These are the main factors that cause the emergence of various infectious diseases.

Nowadays, factors such as the poor implementation of health care services, urbanization and economic poverty also lead to the prevalence of EID. The evolution of viruses and microbes also suggests that infections emerge continuously. The identification of these factors is also a requirement for the effective surveillance and control of EID.

Ecological changes and agricultural development impact EID


The increased proximity of the parasite to the host and favourable conditions are responsible for an increased population of the microbes or its vectors. Approximately 7,000 deaths occur annually in Asia, associated with flooding of fields for rice growing. Natural environmental changes, such as climate or weather anomalies, can have the same effect (Eisenberg et al., 2007). Natural disasters are too responsible for the prevalence of EID. Post-calamities, the hygiene of nature is lost leading to favourable conditions for breeding and spreading of EID. Agricultural development includes the spread of infections from cattle and poultry.

Social and behavioural factors that influence infectious diseases


Social factors like rural-urban migration result in inadequate sanitation facilities and crowded living conditions. Moreover, the lack of basic infrastructure in the cities also causes the prevalence of EID(Suhrcke et al., 2011). All these conditions are associated with population growth and contributed to the resurgence of many diseases, such as tuberculosis, cholera, typhoid, and plague. For example, in India every year there is a re-emergence of malaria endemics every year. This is due to the favourable conditions of the rainy season and a warmer climate. Poor living conditions in densely populated places are also another reason.

Economic factors that influence infectious diseases


These conditions play a major role in impacting the prevalence of infectious diseases. The areas with a lower rate of income are supposed to have a lower level of living conditions. This means a lack of proper sanitation and more people in the same house. Therefore, they become more prone to infectious diseases like diarrheal disease. It is caused by the lack of adequate sanitation and safe water. Lack of investment in the research and development of new vaccines and antimicrobial drugs increases cases of EID (Suhrcke et al., 2011). The inefficiency of adopting new technologies also leads to the development and reoccurrence of infectious diseases. These technologies have the potential to control the spread of infections.

Awareness about a disease

Awareness about the disease among the people impacting the prevalence of EID
Awareness about the disease among the people impacting the prevalence of EID

There are several measures like awareness about the preventive measures i.e. social distancing from the infected individuals, proper and timely vaccinations, etc., to prevent the infectious diseases from spreading (Suhrcke et al., 2011). For example, the demand for measles, mumps and rubella vaccines increased in the case of the measles outbreak. The awareness of the presence of the disease is helpful in reducing the size of epidemics.

Changes in human demographics and behaviour impact EID

Human demographic impact on Emergence and prevalence of infectious disease
Human demographic impact on emergence and prevalence of infectious disease

Major migrations due to ecological (flood, earthquake) or manmade conditions (war) cause infectious diseases to emergence along with rural urbanization (Suhrcke et al., 2011). These are the major sources of the emergence of the threat of infectious disease. For example, dengue hemorrhagic fever is now common in some cities in Asia. High prevalence of infection from the proliferation of open containers needed for water storage. This provides perfect breeding grounds for the mosquito vector.

International travel and commerce

Factors of international travel affecting prevalence of EID
Factors of international travel affecting the prevalence of EID

The infectious diseases spread across the globe due to travel, commerce or war. The people from the affected areas travel to the geographically isolated areas for travel. The individuals in the unaffected area are infected by the diseases brought in by visitors (Suhrcke et al., 2011). Infectious diseases are contagious in nature when people migrate or travel to other places and may risk spreading diseases. Immigration is another reason for the prevalence of EID from one endemic to another. One common example: the Zika virus spread.

Technology and industry impact on EID

Factors of Technology and Industry impacting the EID prevalence
Factors of Technology and Industry impacting the EID prevalence

The improvement in technology and industry impact the prevalence of EID as the diseases can spread from infected individuals to healthy individuals by the means of organ or tissue transplants, globalization of the food supplies etc (Suhrcke et al., 2011). Excessive antibiotic usage causes a change in the genetic makeup of the bacteria making them more virulent upon the adaptation.

Microbial adaptation and change impact EID

Factors of microbial adaptation impacting EID prevalence
Factors of microbial adaptation impacting EID prevalence

Microbes evolve at a very fast pace and so the emergence of antibiotic-resistant bacteria is increasing (Doorn, 2014). In viruses, evolution is caused due to the higher rates of evolution. For example, due to mutation two strains of influenza virus and the new variants reinfect a previously infected person. The altered antigens do not immediately get identified by the immune system.

Breakdown of public health measures and deficiencies in public health infrastructure

Factors of Government attributes that affects the prevalence of EID
Factors of Government attributes that affect the prevalence of EID

The pathogens are often available in the hibernated state in reservoirs or in the environment. Re-emerging diseases are those, like cholera, that was once decreasing but are now rapidly increasing again (Dikid et al., 2013). Poor public health policies and sanitation measures lead to the prevalence of EID. The government of countries with indications of such infectious diseases must make effective public health policies. The government must also provide proper immunization and vector control policies. This will make sure that the emergence and also reemergence of the infectious disease are avoided.

Thus, are the factors affecting the prevalence of Emerging Infectious Diseases (EID) globally. In the next article, the purpose of epidemiological studies is discussed which special reference to EID.


  • Dikid, T. et al. (2013) ‘Emerging & re-emerging infections in India: An overview’, The Indian Journal of Medical Research. India: Medknow Publications & Media Pvt Ltd, 138(1), pp. 19–31. Available at:
  • van Doorn, H. R. (2014) ‘Emerging infectious diseases’, Medicine (Abingdon, England : UK Ed.). Medicine Publishing Company Ltd, 42(1), pp. 60–63. doi: 10.1016/j.mpmed.2013.10.014.
  • Drotman, D. P. et al. (2018) ‘Emerging Infectious Disease’, Ann Itern Med, 24(8), pp. 1401–1608.
  • Suhrcke, M. et al. (2011) ‘The Impact of Economic Crises on Communicable Disease Transmission and Control: A Systematic Review of the Evidence’, PLoS ONE. Edited by J. H. Verbeek. San Francisco, USA: Public Library of Science, 6(6), p. e20724. doi: 10.1371/journal.pone.0020724.