Cholera in endemic districts in Uganda during El Niño rains: 2002-2003

Abstract

Background: El Niño phenomenon causing increased rainfall and flooding has been linked to flare ups and emergence of several disease outbreaks including cholera. The latter has been reported in many districts in Uganda in recent years. Therefore an understanding of factors influencing its pattern of occurrence is needed for effective control.

Objectives: To determine cholera disease status during six months of El Niño rains and assess serotypes and antibiotic sensitivity of isolates.

Methods: A prospective study was conducted in five cholera "endemic districts" in Uganda.

Results: Cholera outbreaks occurred in all the study districts coincident with the onset of the El Niño rains. There were 924 cholera suspect cases reported with 95 fatalities (case fatality rate 10.3%). A total of 388 clinical specimens were analyzed by culture and of these, 168 were positive for V. cholerae. Biochemical and serological analysis identified the isolates as V. cholerae O1, biotype EL Tor serotype Ogawa. Antibiotic sensitivity revealed that isolates were 100% sensitive to ciprofloxacin, tetracycline and erythromycin, whereas sensitivity was variable for other tested antibiotics. Unlike Kampala, where the disease was contained within three months, persistence occurred in other districts only dying out with end of El Niño rains, suggesting differences in disease control.

Conclusion: These results show that El Niño rains cause increase in the number of cholera cases in Uganda, calling for preparedness and a need to emulate Kampala response incase of outbreaks in other districts.