Infectious Diseases

Abstract

Over the past few centuries, infectious diseases have been a prevalent cause for mortality in all types of human demographics. With a daily increase in disease occurrences, it is vital that the general public obtains awareness of pathogenic infections. Because the human body’s immune system is unable to fight against some infectious agents that our body ingests, the other systems in the body also deteriorate, as these systems are reliant on the immune system for safety. Since many people are unaware of the true danger of infectious diseases, they are fueling the spread of such diseases to others.

Introduction

Infections were once the leading cause of death; diseases such as Smallpox, Tuberculosis, Syphilis, Cholera, and the Black Plague haunted families throughout centuries. One notable scare in the history of outbreaks was the 1918 influenza pandemic, causing approximately 40 million deaths. Whilst advances in health aid and studies have caused massive reductions in death tolls due to infectious diseases; it is cardinal to be aware of their workings and preventions.

Infectious agents, e.g. viruses, bacteria, parasites, fungi, cause contagious diseases. When one of these organisms enters a body, the immune system either fights it or develops a weakness for the agent. A weakened immune system due to drugs, age, or other conditions could cause a higher likelihood of the pathogens to form due to the organism.

There are three main components to keep in mind that explain how an individual may contract an infection, i.e. the epidemiological triad: the agent (the organism that causes the diseases—bacteria, viruses, parasites, fungi), the host (the target of the diseases), and the environment (the surroundings and conditions external to the host that allows the virus to be transmitted). The transmission pathways between this triad allow for the direct spread of infections through methods including touching, intercourse, coughing, as well as the indirect spread of pathogens from contaminated objects and vectors such as mosquitos and ticks.

Different categories of diseases also exist: Zoonotic Diseases (diseases of animals transmitted to humans; makes up over 60% of human infectious diseases; e.g. Leptospirosis, Toxoplasmosis, Campylobacter, Rabies), Emerging Infectious Diseases (newly appearing diseases, or diseases that had once existed but are now increasing in incidence or geographical range), Neglected Tropical Diseases (a group of tropical diseases that affect many developing countries, having less global attention; e.g. Leishmaniasis, Tacoma, Sleeping Sickness, Schistosomiasis), and Vector-Borne Diseases (from infected humans or animals to another human by a vector such as flies, fleas, ticks, mosquitos, snails; e.g. Malaria, Dengue, sleeping sickness, Schistosomiasis; causes about 1 million deaths per year).

As diseases spread, many will hear about statistics and updates on the media. However, many news channels use official medical terminology for these diseases, leaving viewers confused. This terminology includes the Incubation period—the period between the start of the infection to when symptoms appear, the Clinical stage—the stage in which symptoms are apparent (there is a significant variation of traits from mild to severe until the disease is resolved or death), and the Infectious period—the time in which the infected person carries and can spread the disease to others. Case fatality measures the severity of the illness in regards to the number of people who die from the infection. The Basic Reproductive Rate is how infectious the disease is, using the average amount of secondary cases caused by one person (e.g. one case of measles can produce up to 15 other cases). There is also Secondary Attack Rate, the proportion of people who develop an infection from exposure to the disease (e.g. seasonal influenza’s Secondary Attack Rate is one out of every ten people exposed to the pathogen develops an infection). While infectious diseases were responsible for three of the top ten cause of deaths in 2012 (lower respiratory tract infections, HIV/AIDS, diarrhoeal diseases), and new diseases emerge, e.g. EBOLA, MERS- science and healthcare has come a long way compared to what it once was.

Contagious diseases have existed since the early stages of humankind. However, the adjustment to agrarian life caused pockets of communities, allowing for the faster spread of diseases. Some of the first ailments to appear during this shift of lifestyle about 10,000 years ago were Malaria, Tuberculosis, Leprosy Influenza, and Smallpox. Pandemics became more frequent the further civilization advanced.

Prevention

Understanding how to control the spread of infectious diseases is helpful for individuals and communities alike. All it takes is one carrier to infect others. There are six main ways to prevent infectious diseases and the spread of them. The first way, advocated heavily by health promotion programs, requires changes in behavior. To reduce or eliminate the risk of exposure to an infectious agent, one should use condoms, wash hands, hold a healthy diet, and use insect repellants. Alongside changes in behavior is the usage of vaccines, known to be a big success among the public health community. Vaccines have led to the eradication and reduction of many diseases. Next is Medication, Antimicrobial medication kills microorganism or prevents their replication by pre prophylaxis or post prophylaxis. One downfall to medication is the emergence of antimicrobial resistance, in which microorganisms develop a resistance to certain drugs due to the excessive or inappropriate usage of the drug (becoming a significant issue even in recent years).

Another paramount way to prevent infectious diseases is through surveillance. The surveillance is often done by doctors and laboratories who send information to health departments by monitoring diseases, characterizing disease patterns, and detecting outbreaks. The fifth way is by taking care of one’s environment. Vector control, safe water, sanitation and hygiene, as well as making sure housing and working conditions, food safety, and air quality are all up to standard. Lastly, we have infection control. Infections can spread rapidly, so it is essential to sterilize equipment- and in health care facilities, PPE, isolate, hand wash, clean, and have reliable surveillance systems. Other ways to prevent infectious diseases is through education, secure healthcare systems, and an efficient health workforce. Human health is considered to be closely related to that of the animals and environment, meaning that the cooperation and collaboration of many specialties are needed (ranging from veterinarians to environmental scientists).

Sources

Let’s Learn Public Health. (2017, February 26). Infectious Diseases - An Introduction [Video]. YouTube.

https://www.youtube.com/watch?v=9axOFtPqS0c

Let’s Learn Public Health. (2017, February 26). Infectious Diseases - How do we control them? [Video]. YouTube.

https://www.youtube.com/watch?v=2JWku3Kjpq0