Epidemiological link of a major cholera outbreak in Greater Accra region of Ghana, 2014

BACKGROUND Cholera remains an important public health challenge globally. Several pandemics have occurred in different parts of the world and have been epidemiologically linked by different researchers to illustrate how the cases were spread and how they were related to index cases. Even though the risk factors associated with the 2014 cholera outbreak were investigated extensively, the link between index cases and the source of infection was not investigated to help break the transmission process. This study sought to show how the index cases from various districts of the Greater Accra Region may have been linked. METHODS We carried out a descriptive cross sectional study to investigate the epidemiological link of the 2014 cholera outbreak in the Greater Accra region of Ghana. An extensive review of all district records on cholera cases in the Greater Accra region was carried out. Index cases were identified with the help of line lists. Univariate analyses were expressed as frequency distributions, percentages, mean ± Standard Deviation, and rates (attack rates, case-fatality rates etc.) as appropriate. Maps were drawn using Arc GIS and Epi info software to describe the pattern of transmission. RESULTS Up to 20,199 cholera cases were recorded. Sixty percent of the cases were between 20 and 40 years and about 58% (11,694) of the total cases were males. Almost 50% of the cases occurred in the Accra Metro district. Two-thirds of the index cases ate food prepared outside their home and had visited the Accra Metropolis. CONCLUSIONS The 2014 cholera outbreak can be described as a propagated source outbreak linked to the Accra Metropolis. The link between index cases and the source of infection, if investigated earlier could have helped break the transmission process. Such investigations also inform decision-making about the appropriate interventions to be instituted to prevent subsequent outbreaks.