传染病学英文版课件：Typhoid fever.ppt

Typhoid fever FENG LINDept. of Infectious Diseases PHHP Typhoid fever, also known simply as typhoid, is a symptomatic bacterial infection caused by Salmonella Typhi. Symptoms may vary from mild to severe and usually begin six to thirty days after exposure. Often there is a gradual onset of a high fever over several days. Weakness, abdominal pain, constipation, and headaches also commonly occur. Diarrhea and vomiting are uncommon. Some people develop a skin rash with rose colored spots. In severe cases there may be confusion. Without treatment symptoms may last weeks or months. Other people may carry the bacteria without being affected; however, are still able to spread the disease to others. Typhoid fever is a type of enteric fever along with paratyphoid fever. EtiologySalmonella Typhi is belongs to the family enterobacteriaceae and Salmonella species “D” group.Gram negativeSurvive in water for weeks Epidemiology In 2000, typhoid fever caused an estimated 21.7 million illnesses and 217,000 deaths. Its occurs most often in children and young adults between 5 and 19 years old. In 2013 it resulted in about 161,000 deaths – down from 181,000 in 1990. Source of infectionTyphoid fever is spread by food and water contaminated by urine and feces 5% of people who contract typhoid continue to carry the bacteria after recover. Route of transmissionTyphoid fever is contracted by the ingestion of the bacteria in contaminated food and water. Susceptible peopleAny age either sex may contract typhoid feverInfants, children, and adolescents in south-central and Southeast Asia experience the greatest burden of illness. outbreaks of typhoid fever are frequently reported from sub-Saharan Africa and countries in Southeast Asia. Historically, in the pre-antibiotic era, the fatality rate of typhoid fever was 10–20%. Today, with prompt treatment, it is less than 1%. About 3-5% of individuals who are infected will develop a chronic infection in the gall bladder. Since S. Typhi is