Medical terminology for our times


One result of the COVID crisis has been the frequent use of certain medical terms. Although these have precise scientific and medical definitions, their use in more common media has sometimes led to confusion or misunderstanding.

An understanding of needed medical terminology can start with the term “disease”. In its broadest sense a disease refers to any condition that causes pain, dysfunction, distress, social problems, or death to the person afflicted. There are four types of diseases: infectious diseases, deficiency diseases, hereditary diseases, and psychological diseases. Diseases are also classified as communicable versus non-communicable.

Two sources of infectious diseases are bacteria and viruses. Bacteria are unicellular organisms that lack a few organelles and a true nucleus. Some bacteria are useful to humans, but some are harmful and are responsible for many infectious diseases such as pneumonia, tuberculosis, diphtheria, and tooth decay. In contrast, a virus is a small collection of genetic code (DNA or RNA) surrounded by a protein coat. A virus cannot replicate by itself alone, it must infect cells and use components of the host cells to make copies of itself. Researchers estimate that viruses outnumber bacteria by a ratio of ten to one.

The World Health Organization (WHO) uses three terms to describe the rate of spread of infectious diseases: epidemic, endemic, and pandemic. An epidemic is an unexpected increase in the number of disease cases in a specific geographical area. The WHO will declare a pandemic when a disease’s growth is exponential.

A pandemic covers a wide area, affecting several countries and populations. A disease outbreak is endemic when it is consistently present but limited to a particular region.

Humans have an internal natural immune system to help fight diseases. This immune system is a network of biological processes that protects us from a wide variety of pathogens. Active immunity can also be generated artificially through vaccination.

However, there is a major difference in control of diseases caused by bacteria and diseases caused by viruses. Adverse bacterial effects can be rectified by taking antibiotics. Antibiotics are antimicrobial drugs obtained from other organisms to combat harmful microorganisms. However, antibiotics are NOT effective against viruses. Only antiviral medications or vaccines can eliminate or reduce the severity of viral diseases.

To protect public health and safety, it is often necessary to track a disease’s incidence and to trace the disease back to its origin. This is the science of epidemiology.

The current COVID-19 is not the first pandemic to wreak havoc on humanity.

Significant outbreaks in the last one hundred years include the Spanish Flu (1919 – 1921 with over 50 million deaths), the Asian Flu (1957 – 1958, 1.1 million deaths) and the AIDS Pandemic (1981 – present, 35 million deaths). From these outbreaks, we are learning more about good health and sanitation measures. But we must remain vigilant and follow scientifically proven methods for control. We can now identify most diseases, but we must be prepared to follow necessary health and safety regulations during the period when a disease is active in our population.