[Large-scale selective antibiotic prophylaxis during the 2004 cholera outbreak in Douala (Cameroon)].

Introduction: During the 2004 cholera outbreak in Douala, densely populated and poor suburban populations had very poor access to safe drinking water and were at high risk of transmission. The provincial task force thus decided to provide preventive antibiotic treatment of all patient contacts, that is, family members taking care of patients in the hospital and household members of patients or close neighbours living in houses directly adjacent to patients.

Methodology: This retrospective report, based on data from hospitals, local cholera committees, and pharmacies, describes the course of the epidemic, bacteriological monitoring, and antibiotic distribution.

Results: Suddenly appearing in January 2004, the outbreak affected 5,020 patients in 8 months. V.cholerae, which was isolated in 111/187 samples, remained susceptible to doxycycline, amoxicillin, and fluoroquinolones. A total of 182,366 persons (35 contacts per patient) received antibiotic treatment. The rate of contacts among new patients fell from 30% to less than 0.2%.

Discussion: Antibiotic prophylaxis was a part of a comprehensive package of community interventions that included health education, disinfection of homes, latrines and wells in all affected households, and bacteriological monitoring. Although it reduces the risk of the disease, mass antibiotic prophylaxis is not recommended against cholera outbreaks, because it does not prevent contamination and is limited by contraindications, costs, and modes of administration. Moreover, it increases the risk of developing resistance. It is impossible to eradicate vibrio from the environment. The individual risk of contracting cholera is not known and it is difficult to assess the impact of a collective prevention strategy. Because the bacteria remains susceptible to antibiotic drugs, a well-targeted antibiotic prophylaxis made it possible to reduce direct human transmission of cholera. This reduction did not affect the overall epidemic, however, because of the massive environmental contamination.

Conclusion: The role of chemoprophylaxis in limiting cholera epidemics is difficult to ascertain. Large-scale prophylaxis should be selective and limited to close contacts, in accordance with WHO recommendations, with rigorous application and monitoring of both integrated prevention procedures and antibiotic susceptibility.