An Intuitive Model for Novel Coronavirus Infection Spread and Control
Posted on 09 Feb 2020; 00:01 AM IST. Last Updated: 09 Feb 2020; 00:01 AM IST.
Summary: This article attempts to explain the mechanisms of novel coronavirus (Covid19) spread, with the help of an intuitive model, built upon logical ground facts.
Introduction
The following is an intuitive model for Corona Virus infection, proposed by a software professional, who has zero knowledge in Biology. Information modeling is an interdisciplinary subject, and I thought my two-cents worth of contribution (in information modeling), could help biologists and administrators, in tackling this menace.
The Basic Model
The infection may be categorized as -
none : No Infection;
mild : Infected but no symptoms;
moderate : Infected with non life-threatening symptoms;
severe: Infected and under distress;
A region or place contains people. We can put people of the above categories in a region, in any combination. The following example, depicts two regions or places called R1 and R2, which need not co-exist in a country or geographical location.
R1 = { 7 persons with mild infection, 2 persons with moderate infection,
1 person with severe infection, 990 persons with no infection };
R2 = { 300 persons with mild infection, 150 persons with moderate infection,
50 persons with severe infection, 500 persons with no infection };
It may be noted that the two regions or places R1 and R2 have the same number of people, which is 1000. In a real-life scenario, the regions could only have approximately similar population sizes.
The configuration of R1 is distinctly different from the configuration of R2.
The density of infection of R1 = 10 / 1000 = 0.01 or 1%;
The density of infection of R2 = 500/1000 = 0.5 or 50%;
The Logical Thought Process
First Logical Assertion: A REGION contains PEOPLE, and the sum total of their infections. In other words, the REGION is INFECTED, not just PEOPLE.
Second Logical Assertion: The SPREAD of the infection, is PROPORTIONAL to the DENSITY of the infection in the REGION. This is with respect to external interactions or with respect to external visitors. From a diagnostic perspective, a random visitor landing in region R1, could have 1% chance of catching the infection, whereas a random visitor landing in region R2, will have 50% chance of catching the disease.
Third Logical Assertion: The RAISE in the infection DENSITY of a REGION is PROPORTIONAL to the activity of the population. This is with respect to intra-region interactions, or with respect to its own population. From an administrator point of view, PEOPLE should not move. A bag of food, and/or medicines can be left at the door-step, by Government agencies, without human interaction.
Fourth Logical Assertion: The SPREAD of the infection by a PERSON, is NOT ONLY PROPORTIONAL to the severity of infection in the person's body, but also depends on the contact-type, and proximity. An apt clinical guidance could be aimed at maintaining limited contact, at a good length distance.
Fifth Logical Assertion: The mild infections which have no symptoms, and no possible detection, are an administrators nightmare. Ideally, all infected persons MUST BE QUARANTINED. But since, mild infections cannot be detected, what can be done is to "ISOLATE MODERATE & SEVERE CASES AS EARLY AS POSSIBLE".
The Inference System
The above model is nothing but a formal articulation of various administrative guidelines suggested by the organizations of the World , or administrative actions already enforced in China by its Government. I believe the model is fair, and the formal elucidation, just adds an ability to ask questions, or seek inferences, which in fact is the whole purpose of this effort.
First Logical Inference: If the model were to be in place, for at least a month, then there should be no raise in the number of infections. Conversely, if there is a raise in the number of infections, then either the model or its parameters are incorrect. My first suspicion is the "2-weeks time parameter" given for manifesting symptoms, after contracting the disease.
Second Logical Inference: The sheer volume of infections, raises the doubt, if a liquid medium is required for the spread. The number of cases can be easily explained, if "air alone is regarded as the medium", for the spread of the disease.
Conclusion
The questions raised above are on the minds of many, as doubts and fears. An emergency guidance is needed to help Governments of many countries around the world, in protecting their people.