Epidemic diseases are the diseases which are infectious and contagious.
Epidemic diseases are the diseases which are infectious and contagious. It is the spread of a disease in a particular region or area. It spreads when the infectious agent and the susceptible host are present in large numbers. An epidemic may be caused due to the following factors:
The epidemic diseases are of three main types:
It is the kind of epidemic in which all the cases are infected by a single source at the same time.
An epidemic in which a causal agent such as contaminated water and the food is infecting people over a long period of time is known as the continuous source.
It is the type of epidemic in which the causative agent is transmitted from one person to the other allowing the epidemic to spread.
Cholera is a water-borne disease that spread due to bacterial infections. The third cholera is the largest cholera outbreak known to the world. It originated in India and later on spread beyond the Indian boundaries.
It broke out in China and took the lives of one to two million people.
It is a respiratory tract illness caused by the coronavirus. It is believed to be transmitted from animals and took the lives of many people.
It is a rarely occurring deadly virus that causes body ache, fever, and diarrhoea. It was transmitted from wild animals. It proved to be fatal for a large number of population.
This disease is believed to have spread from chimpanzees to humans in the 1920s. The virus attacks the immune system and reduces its efficiency. This disease is estimated to have taken the lives of 25 million people. Extended reading: AIDS
A pandemic disease is an epidemic that has spread across a large area such as multiple continents or worldwide. HIV/AIDS is one of the most destructive pandemic diseases that broke out all over the world. Influenza is another pandemic disease and has occurred more than once. COVID-19 is another recent example. The pandemic is caused by a new infectious agent that has never caused a disease before. It has faced a larger death toll than the epidemic diseases. Antibiotic resistance and increased travel and mobility have increased the risk of diseases among humans.
A type of influenza virus known as the influenza A virus changed suddenly into a new virus that is different from all the existing viruses. This happens due to the change in the HA and NA proteins. When this new virus sub-type spreads among the people, it results in a pandemic.
Q.1. What is an outbreak? A.1. An outbreak is declared in a particular region when multiple cases of a disease are observed or recorded. Q.2. Can you give one example of a recent outbreak in India? A.2. The Nipah virus outbreak in Kerala in the year 2018. COVID-19 is another example observed in recent times.
The outbreak of the disease is limited to a particular region
Disease outbursts across a wide geographical region affecting a huge population
Example – Asian Influenza, HIV/AIDS, Cholera