Question

Explain how and why each of the following is expected to contribute to the R₀ of an infectious epidemic.

1. Infectious dose
2. Mode of transmission
3. Length of infectious stages
4. Severity of symptoms
5. Social distancing

Answer 1

Ro (basic reproduction number) is the measurement for transmission potential of a disease.Several factors contribute to the RO of an infectious epidemic

Infectious dose - number of units of infectious agent is required to produce disease is important and related to basic reproduction number of agents.Higher the infectious dose with low RO may reduce the severity of epidemic and vice versa.

Mode of transmission - Mode of transmission is extremely important factors whcih may increase or decrease the RO.Suppose if mode of transmission air and touch (highly contagious) which we always come in contact with,the spread of the disease would be high means increased Ro. If mode of transmission is either via faecal matter or by digesting some infected things,then it can be mostly controlled and transmission potential will be less.

Length of infectious stages - It is divided into incubation period,predromal period, period of illness,period of decline and period of covalescence. The length of these period depend on the infectious agent. The lengthy predormal (dividing) period and period of illness will have more transmission potential.

Severity of symptoms -Severity of symptoms can equally contribute to the RO value.More severe the symptoms in period of illness will elevate the transmission potential.

Social distancing - It can reduce the transmission potential when infectious agent is highly contagious and spread from one person to another eaisly.if the mode of transmission is different then it might not affect.