With reference to three named diseases, write an essay on emerging infectious diseases
Introduction
The aim of this essay is to explain the emergence of three infectious diseases that have affected the world in the last 20 years. This essay will be describe factors which may cause emergence and will also show case studies of three chosen diseases. The essay will focus on three diseases: Staphylococcus aureus (vancomycin-resistant), a bacterial disease of which emerged in the U.S. in 2002 (Institute of Medicine of the National Academies 2003). The Dengue fever (also the Dengue Hemorrhagic fever and shock syndrome), a viral disease of which the first major emergence was Hawaii in 2001-2002 (Institute of Medicine of the National Academies 2003). Finally, Cholera caused by the bacteria Vibrio cholerae of which emerged in West Bengal in 1998 (Sur D, 2000).
Reasons for emergence of Infectious Diseases and Prevention
There are a large number of reasons for emergence of new infectious diseases in this current day. A few of the factors include: increased international activities, antibiotic resistance and the occurrence of natural disasters and the poor way in which some are dealt with.
Improved technology and increasing want for travel and tourism in the 21st century means that there has been a lot more contact between people from different cultures. This can lead to the introduction of new diseases to different countries around the world where international commerce is now possible at faster times than what it takes to actually acquire the symptoms for a disease, meaning that if an outbreak is to be contained within the nation of outbreak, strong measures would have to be put into place in order to prevent the disease from spreading from an epidemic to a pandemic. Increased transport of items and animals on an international level would also increase the risks of emergence of diseases acting as vectors for many diseases allowing international spread of infections, whether it be through transfer between animals or through unsafe foods. Increased infrastructure in more areas such as subtropical and tropical areas, increases the amount of people travelling and living in these areas and so creates a new community of which have increased exposure to the diseases found in these hotter areas of the world and more specifically their vectors. Dengue fever is a virus of which is transmitted through the mosquito Aedes aegypti as a vector (Institute of Medicine of the National Academies 2003). The Institute of Medicine of the National Academies states that the disease is worsening in Latin America and Asia due to the increasing size of tropical cities alongside poor mosquito control in some of the less economically developed countries, meaning that more cases will arise without any extreme measures of prevention and an increasing population in these countries. Bhatt et al. suggests that it is common throughout tropical areas where the risk and intensity of the virus is determined by factors such as temperature, rainfall and population/urbanisation. Bhatt et al. also suggested that the areas most at risk were those of the Americas and Asia where from 96 million apparent dengue infections in 2010, 70% of the infections were found to be in Asia whilst 14% of the infections were found in the Americas.
Antibiotic resistance has become more widespread in the 21st century where the increased use of these drugs has come at the expense of adoption of a survival of the fittest approach by the microorganisms of which it is used against. Over the years the increased usage of antibiotics against bacteria has caused changes in the chromosomes or the exchange of genetic material between bacterial organisms via plasmids, leading to some bacteria adopting the resistance genes of which make antimicrobial agents useless, allowing the resistant bacteria to effectively reproduce and produce a new strand of the disease of which is resistant to specific antibiotics. An example of this is vancomycin-resistant bacteria Staphylococcus aureus, the Institute of Medicine of the National Academies found that the infectious bacteria had emerged in the U.S in 2002 as a result of continuous use of antimicrobials, allowing a vancomycin-resistant strain to arise where risk of transmission was high amongst patients in hospitals, increasing likelihood of spread to the community as a result of the resistance paired with an ideal area for reproduction. Chang, Soju, et al. explained a specific case where a patient treated for foot ulcers was taking vancomycin for six and a half weeks in which time a resistant form of the bacteria had formed and reproduced gaining the vanA resistance gene of which dampened the effects of vancomycin on the patient, this shows how quickly bacteria can adapt and inherit genes, showing that careful measurements should be taken to prevent bacteria from gaining multiple resistance genes through the use of a variety of combating techniques such as antibiotic control programs, improved sanitation also hygiene and the development of more antibiotics.
Finally, natural disasters throughout the years have had a big influence on the emergence of diseases. A lot of factors have to be taken into consideration when trying to prevent an epidemic after a natural disaster has occurred; a large population losing their housing could lead to overcrowded environments in lesser affected area making transmittance of disease between people a lot easier. The type of disaster also has to be considered; an earthquake may cause a high amount of deaths, however, a tsunami would leave contaminated water of which is an easy vector for many diseases that arise in the aftermath, thus sanitary solutions must be well thought out. A lack of aid after a natural disaster also contributes, where people without food and clean water may become more desperate to keep themselves and their families alive, leading to consumption of unclean water and spoilt food, increasing the range of diseases of which emerge. An example of a disease of which has emerged as a result of natural disasters is cholera, more specifically an outbreak of cholera in West Bengal, 1998 of which followed severe floods (Sur D, 2000). West Bengal in an area of which is overpopulated and so this would have been a key reason for emergence of cholera within its population with over 16000 incidences of cholera reported. This region is also a fairly poor region and so may not have been able to cope with the funding for sanitation measures, without significant aid.
Conclusions
To conclude, we can see that emergence of diseases nowadays, can be due to our own actions; we can see examples of this where we have overused antibiotics, possibly for greed, which has led to antibiotic resistance. They can also emerge as a result of increased international travel and trade; increased travel means increased contact between people from different cultures from all over the world and so increased transmittance. Increased Infrastructure and a lack of measures/money/knowledge to prevent emergence occurring in less economically developed countries can also lead to fast paced epidemics. As a final point natural disasters and the way they are dealt with also determines whether or not infectious diseases will emerge or not.