What are Epidemics?
An epidemic develops when new cases of a particular disease spread rapidly in a given human population in a given period. The disease may not be communicable always. This may be limited to a region or may be global. In such case, it is known as pandemic. If a few cases of a rare disease are reported, it is categorized as an epidemic. Here are a few lines explaining types of epidemics.
Generally epidemics follow a certain pattern based on the environmental and geographical conditions, the characteristics and distribution of host population and the cultural behavior. The epidemics may recur if there is no change in the above discussed conditions. Hence, it is good to have some knowledge on several types of epidemics.
Types of Epidemics:
- Seasonal epidemics:Some diseases like pneumonia and influenza are most common in winters, while diarrhea is more prevalent during rainy and summer seasons. If an epidemic occurs in a particular season, it is called seasonal epidemic.
- Propagated Epidemics:If an epidemic is infectious and transmits from one person to another, it is known as propagated epidemic. This shows a gradual rise and reduces slowly over a period of time. This type of epidemic spreads till there are no susceptible individuals. These epidemics are more dangerous when people gather in crowds like festivals and fairs.
- Cyclical Epidemics:Certain epidemics may occur in cycles that recur after a period of time that may be years, months, weeks or days. Measles V is a type of cyclical epidemics which occur in every 2 – 3 years.
- Common Source Epidemics:The common source epidemics originate from a single source of infection of disease-causing agent. It is categorized into two:
Multiple or continuous exposure epidemics: In this epidemic type, the source of infection exists until the source is removed. A public well with the contaminated water is the common source of infection and the health condition may prevail till the well water is made safe.
Single exposure or point source epidemics: In this, the disease agent spreads the epidemic to susceptible population only once and at one point of time. Food poisoning is a good example for this as the contaminated food is consumed only once. In point source epidemic, there will be a sudden increase of cases and declines at the same pace.
- Epidemic of Non-Communicable Diseases:Due to advancement of science and technology, there is a change in lifestyle that is affluent and sedentary with a slight physical activity. This resulted in increase in health issues such as mental diseases, diabetes, heart disease and hypertension. In the recent times, the non-communicable diseases have become epidemics.