Which one of the following is characteristic of a single exposure common vehicle outbreak? (DNB June 11)
|A||Frequent secondary cases|
|B||Severity increase with increasing age|
|D||Cases occur continuously beyond the longest incubation period|
In Point Source Epidemics, the exposure to the disease agent is brief and essentially simultaneous and the resultant cases all develop within one incubation period of the disease.
Vehicle-borne transmission means transmission of infectious agents through the agency of water, food, ice, blood, serum, plasma or other biological products such as tissues and organs. Of these, food and water is most frequent vehicle of transmission as everyone uses them. If the dose of contamination is heavy, the outbreak may be explosive as in the case of cholera and hepatitis A epidemics.