Mode of Transmission

Typhoid is transmitted mainly by faeco-oral route. The bacilli are excreted for varying periods in Faeces and urine of cases and carriers. There is no evidence that the bacilli are excreted in sputum of milk. Typhoid infection can spread through

Contaminated drinking water or food. Large epidemics usually related to faecal contamination of water supplies.
Contaminated food/drink due to poor personal hygiene and food handlers including carriers.

Vehicle transmission: The major vehicles of infection are water and food, contaminated by faeces or urine of infected patients or carriers. Paratyphoid fever is seldom conveyed by water unless the infecting dose is large; it is generally transmitted by contaminated foods,
e.g. ice, ice-cream, frozen foods, confectionary.

Direct contact: A small proportion of typhoid cases may occur due to direct transmission of infection through contaminated hands. The hands may be contaminated while handling patients, their excreta or infected linen. Transmission by flies is also a possibility in endemic areas.