<prompt> A contact carrier in cholera has the following characteristic -Gall bladder is infectedStools are not positive for cholera vibrioDoes not play any role in spread of infectionDuration of carrier state is less than 10 days  <response>: The duration of contact carrier state is usually less than 10 days. The gall bladder is not infected. It plays an impoant role in the spread of cholera. The stool culture is frequently positive for V. cholera O1. Park;s textbook of preventive and social medicine,K.Park,23rd edition,page no:230. p 