Which of the following about cholera is true ?

Ans. is 'd' i.e., Vibriocidal antibody titre measures prevalence . Serological examination is of little use in the diagnosis of cases though it may be helpful assessing the prevalence of cholera in an area. The complement dependent vibriocidal antibody test is the most useful. Other tests are : Indirect hemagglutination Antitoxin assay Agglutination using live or killed vibrio suspensions. About other options Throughout the course of infection, the vibrios remain attached to the epithelium but do not damage or invade the cells. . V. cholerae possesses the endotoxin but it has no role in pathogenesis. . Recent infection in India are of E-1 Tor vibrios.