Epidemic waves of cholera in the last two decades in Mozambique

Abstract

Introduction: Africa is increasingly affected by cholera. In Mozambique, cholera appeared in the early 1970s when the seventh pandemic entered Africa from the Indian subcontinent. In the following decades, several epidemics were registered in the country, the 1997-1999 epidemic being the most extended. Since then, Mozambique has been considered an endemic area for cholera, characterized by yearly outbreaks occurring with a seasonal pattern.. At least three pandemic variants are thought to have originated in the Indian subcontinent and spread worldwide at different times. To understand the epidemiology of cholera in Mozambique, whether the disease re-emerges periodically or is imported by different routes of transmission, we investigated clinical V. cholerae O1 isolated during 1997-1999 and 2012-2014 epidemics. Methodology: By detecting and characterizing seven genetic elements, the mobilome profile of each isolate was obtained. By comparing it to known seventh pandemic reference strains, it was possible to discern among different V. cholerae O1 variants active in the country. Results: During 1997-1999, epidemic strains showed two different genetic profiles, both related to a pandemic clone that originated from India and was reported in other African countries in the 1990s. Isolates from 2012-2014 outbreaks showed a genetic background related to the pandemic strains currently active as the prevalent causative agent of cholera worldwide. Conclusions: Despite cholera being endemic in Mozambique, the epidemiology of the disease in the past 20 years has been strongly influenced by the cholera seventh pandemic waves that originated in the Indian subcontinent.

Multi-site cholera surveillance within the African Cholera Surveillance Network shows endemicity in Mozambique, 2011–2015

“…Each surveillance zone showed a different pattern of suspected cases distributed over time, although there were clear similarities in the seasonality of suspected cases between the surveillance and outbreaks zones. This heterogeneity may be explained by the hypothesis that in Mozambique outbreaks do not evolve locally, but rather follow cholera re-introduction from distant epidemic regions [ 7 ]. Our study allowed for the measurement of cholera incidence prospectively.…”

A rapid qualitative assessment of oral cholera vaccine anticipated acceptability in a context of resistance towards cholera intervention in Nampula, Mozambique

“…Mozambique has experienced several large cholera outbreaks over the past four decades [1] with 2536 cases reported between September 2015 and July 2016 alone. Half of all cholera cases (50.9%) were reported in Nampula City, the third largest city in Mozambique, situated in the north of the country [2] ( Fig.…”

Oral cholera vaccine coverage during a preventive door-to-door mass vaccination campaign in Nampula, Mozambique

“…Approximately 1.3 billion people are at risk of cholera in endemic countries. An estimated 3 million cases and 95,000 deaths occur each year around the world [ 1 ], particularly in endemic countries where access to water and sanitation infrastructure is inadequate [ 2 , 3 ], including Mozambique [ 4 , 5 ]. The use of oral cholera vaccine (OCV) has become an essential strategy for prevention and control of cholera [ 6 , 7 ].…”