Understanding the Reproduction Definition

Reproduction Ratio (R0). Definition

It is the expected number of secondary cases produced by a primary case

Ex. R0=4

Pre

vale

nce

Nb

of in

fect

ed a

nim

als

Time

The pathogen is able to invade the susceptible

population

R0 over 1

Pre

vale

nce

Nb

of in

fect

ed a

nim

als

Time

The pathogen remains at the same level

R0 equal 1

R0 below 1 Between-animal transmission cannot maintain a disease in a

population

Time

Pre

vale

nce

Nb

of in

fect

ed a

nim

als

.

R0 =1

Pre

vale

nce

Nb

of in

fect

ed a

nim

als

Time

R0 > 1 the pathogen is able to invade the susceptible population

R0 < 1 between-animal transmission cannot maintain a disease in a population

Reproduction Ratio (R0 ). Effect