Typhoid

epidemiology, prevention and control

1. EPIDEMIOLOGY, PREVENTION AND CONTROL OF TYPHOID FEVER PRESENTED BY : TARANNUM NAZ ROLL NO. 137 PARA H2

2. Introduction Typhoid fever is a result of systemic infection mainly by Salmonella typhi . The disease is clinically characterized by a typical continuous fever for 3 to 4 weeks.

3. PROBLEM STATEMENT WORLD: In 2004, WHO estimated the global typhoid fever disease burden at 21 million cases annually resulting in an estimated 2,16,000 to 6,00,000 death per year. INDIA: Reported data for 2011 shows 1.06 million cases and 346 death. Prevalence rate - 88 cases per lac population death rate is 0.029 per lac population

4. Epidemiological determinants Agent Factors : Agent: Salmonella typhi Reservoir of infection: Man Persons who excrete the bacilli for more than a year after a clinically attack are called chronic carrier. In most chronic carriers, the organisms persist in the gall bladder and in the billary tract. (A famous case of ‘Typhoid Mary’’who gave rise to 1300 cases in her lifetime.)

5. Host Factors: Age: 5 to 19 yrs Sex: more in males. Environmental and Social Factors : Peak incidence: July to September Incubation Period: 10 to 14 days

6. M ode of transmission : The disease is transmitted by faeco -oral route or urine-oral route

7. CLINICAL FEATURES Chills and high fever. Prodromal Stage: Malaise , Headache, Abdominal Pain and Constipation Later Stage: Splenomegaly , Abdominal tenderness, Relative bradycardia Intestinal perforation and hemorrhage occurs as complication

8. LABORATORY DIAGNOSIS Microbiological Procedure : By Isolation of S.typhi from blood, bone marrow and stools. Serological Procedure : By Felix Widal Test which measures agglutinating antibody level against O and H antigen New Diagnostic Test : IDL Tubex test: This can detect IgM09 antibody from patients within a few minutes.

9. CONTROL CONTROL OF RESERVOIR: Cases: Diagnosis- By culture of blood and stools. Notification Isolation- till 3 bacteriologically negative stool and urine reports are obtained. Treatment- Fluoroquinolones are drug of choice.

10. Carriers: Identification Treatment- intensive course of ampicillin or amoxicillin for 6 weeks Surgery – Cholecystectomy with ampicillin therapy is very successful. CONTROL OF SANITATION: Purification of drinking water supply, improvement of basic sanitation and promotion of food hygiene are essential measures.

11. IMMUNIZATION Vi Polysaccharide vaccine – 25µg of antigen is subcutaneously administered. Vaccine is stable for 6 months at 37ºC and for 2 years at 22ºC. Schedule- Vaccine is licensed for individuals greater than 2 yrs. Only 1 dose is required and vaccine confers protection 7 days after infection. To maintain protection, revaccination is recommended every 3yrs

12. Type 21a vaccines – Orally administered, live attenuated, Ty2 strain of S.typhi in which the genes responsible for the production of Vi, have been mutated chemically. Schedule- Capsules are licensed for individuals greater than 5yrs. Vaccine is administered every other day, on 1, 3 and 5 th day, a three dose regimen is recommended with this. Immunity is achieved 7 days after the last dose.

13. REFERENCES : PARK’S TEXTBOOK OF PREVENTIVE AND SOCIAL MEDICINE WIKIPEDIA