Typhoid fever

Generalities
Agent	Bacteria: salmonella enterica subsp. enteric serovar typhi or paratyphi A, B or C
Incubation period	- Typhi: 3 to 60 days (8-14 days) - Paratyphi: 1-10 days
Period of transmissibility	- As long as the bacteria is in feces, usually after the 1st week of illness through convalescence . - Approximately 10% of untreated cases will excrete S. typhi for 3 months and between 2-5% of all cases become chronic carriers.
Reservoir	Humans
Modes of transmission	- Consumption of contaminated food: shellfish, fruits /vegetables, milk and milk products by food handlers - Food can be contaminated by flies - Consumption of contaminated water - Sexual transmission
Clinical presentation	a) Systemic bacteria infection: -Mild illness: low grade fever, malaise and dry cough,disturbances of bowel function(constipation in adults, diarrhea in children), headache, malaise and anorexia. Bronchitic cough is common in the early stage of the illness. During the period of fever, up to 25% of patients show a rash or rose spots, on the chest, abdomen and back. -Severe illness: abdominal discomfort, altered mental status and multiple complications(intestinal hemorrhage or peritonitis due to intestinal perforation) b) Carrier state: 1-5% of patients, depending on age, become chronic carriers harboring S.typhi in the gallbladder
Resources
Case definition	MOPH circular no 46 (2007)
Forms	- General reporting form - Typhoid Fever investigation form
Data	Refer to "Surveillance Data" section