Science, Art, Litt, Science based Art & Science Communication
Q; what are the stages of a disease transmission?
Speaking about a spread of disease among humans, the term transmission refers to the transmission of microorganisms from one infected individual to another uninfected person, either through direct contact, through droplets, or through indirect contact such as surface contamination.
Stage 1 is when cases of infected people are imported from affected countries without any local origin in that particular home city or country. Here, only those who have travelled abroad test positive for the respiratory illness. The disease does not spread locally at this stage. Hence, the number of people infected is also quite a few in number, all of them being afflicted with the disease only due to traveling to other nations wherein the infection has already been triggered in many people.
This is the stage when local transmission occurs and its source i.e. the infected patient who possibly had a travel history to other already affected countries, is known and can be located. At this stage, people testing positive have come in contact with a patient who has travelled outside the country, most of whom are friends and relatives of the affected individual. They would have come in close contact with the coronavirus patient in situations such as family get-togethers, or occasions where many people gather like in weddings and parties.
Although the number of cases of infected people increases at this stage, it is still manageable to treat the people with the disease as it is still easy to locate them and provide prompt medical care. Home quarantine and social distancing measures help to prevent the progression of the disease to stage 3 of community transmission.
This is the stage of community transmission and takes place when the source of an individual’s infection can’t be traced and isolated. During this stage, those who have not been exposed to an infected person or anyone who has a travel history to affected countries still test positive for the coronavirus. The outbreak will spread fast in clusters once the community transmission starts.
At this stage of disease transmission, the individuals within a city or community begin to contract the infection randomly, hence making it more challenging to track down all those who could possibly have the disease.
Stage 4 is the most severe stage of an infectious disease spreading within a country. At this point, there are several clusters of the infection, in many different parts of the country and it takes the form of an epidemic. Massive numbers of people are infected, across all age groups, many deaths are reported amongst the elderly and immune-compromised patients, making it very difficult to control the spread of the disease.
In situations like these, the government officials of the affected country announce stringent legislation, instructing all citizens to stay indoors, enforcing a lockdown, shutting down all public places, banning any gathering of large groups of people. These extreme steps are taken, to avoid further fatalities due to the disease and save the healthy population form contracting the infection.