Cholera Outbreaks in Zambia: An Ongoing Battle
Despite efforts by the Global Task Force on Cholera Control (GTFCC) to eliminate cholera in at least 20 countries by 2030, Zambia has experienced a continuous increase in cholera outbreaks over the years. The country, which had set out to lead elimination efforts by 2025, is now coming off its most significant outbreak to date, with 23,381 cumulative cases and 740 fatalities.
As the Zambian government conducts a mid-term revision of its National Cholera Control Plan, it is crucial to understand the published knowledge on cholera in the country and learn from lessons and evidence-based practices that could contribute to reduced cholera mortality and overall case numbers by 2030.
This scoping review aims to address two key questions:
- What is known about cholera in Zambia?
- What are the main suggested mechanisms and strategies to further cholera control efforts in the region?
Methodology and Findings
A scoping literature search was conducted in PubMed to identify relevant studies published between January 2013 and June 2024 using the search terms ‘cholera’ and ‘Zambia’. A total of 45 relevant publications were identified, along with an additional 6 studies from alternative sources.
The analysis revealed several important findings:
Increasing Frequency and Severity of Outbreaks
Over the years, Zambia has consistently experienced major cholera outbreaks every 3-5 years, with increasing intensity and fatality. The outbreaks were predictable in terms of timing, with most occurring during the rainy season. This trend is expected to continue, with outbreaks anticipated to increase in frequency by 300% in the near future due to recurrent climate events like El Niño.
High-Risk Areas and Risk Factors
The majority of cholera cases (over 80%) were identified in peri-urban areas, particularly in the capital city of Lusaka. The major risk factors for recurrent outbreaks included poor access to water, sanitation, and hygiene (WASH) services in urban unplanned settlements and rural fishing villages. Other factors such as rural-urban migration, movement between districts and neighboring countries, and environmental contamination also contributed to the disease’s persistence.
Challenges in Surveillance and Reporting
It is believed that the true burden of cholera in Zambia is underreported, as most reporting is based on case definitions during outbreaks. The country’s cholera cases are often only confirmed by stool culture during outbreaks, while asymptomatic or milder cases may go undetected, particularly outside of the outbreak seasons.
Limitations of the Cholera Elimination Plan
Despite the adoption of the first iteration of the Multisectoral Cholera Elimination Plan in 2019, the steady increase in cases and deaths has continued. This indicates the need to reclassify Zambia as an endemic country eligible for cholera control, rather than elimination, in line with the GTFCC guidance.
Opportunities for Decentralized, Community-Centric Interventions
Interventions are best planned using a decentralized, community-centric approach to surveillance and case management through case-area targeted interventions. This has been seen to be effective in countries like Uganda, the Democratic Republic of Congo, and Burundi, which are also working towards cholera elimination.
Potential of Oral Cholera Vaccines and Climate-Resilient WASH Investments
The predictable geographic location and seasonality of the outbreaks could be used to envisage the location and timing of repeat vaccination campaigns, including pre-emptive campaigns before the rainy season. Additionally, climate-resilient WASH investments tailored to the specific needs of different localities are crucial to address the persistent risk factors.
Recommendations and the Way Forward
Based on the findings of this scoping review, several recommendations can be made to enhance cholera control and elimination efforts in Zambia:
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Adopt a Decentralized, Community-Centric Approach: Interventions should be planned at the district and ward levels, with a focus on case-area targeted interventions and enhanced cross-border surveillance and response activities.
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Align Health and WASH Investments: Advocate for multisectoral interventions that align health and WASH investments, in line with the GTFCC’s Roadmap to Cholera Elimination by 2030.
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Leverage Oral Cholera Vaccines: Utilize the predictable seasonality and geographic patterns of outbreaks to plan for pre-emptive and multiyear vaccination campaigns as a bridge to increased WASH investments.
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Enhance Climate-Resilient WASH Infrastructure: Invest in climate-resilient WASH infrastructure, tailored to the specific needs and challenges of different localities to address the persistent risk factors.
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Improve Surveillance and Reporting: Strengthen surveillance efforts to better capture the true burden of cholera, including asymptomatic and milder cases, and enhance data reporting mechanisms.
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Conduct Further Research: Prioritize research to address gaps in knowledge, such as patient-level information on survival and transmissibility, the role of host genetics and the gut microbiome, and the impact of climate change on cholera dynamics.
By implementing these strategies, Zambia can make significant progress in its efforts to control and eventually eliminate cholera, aligning with the GTFCC’s global roadmap. The lessons learned from this scoping review can also be applicable to other sub-Saharan African countries facing similar challenges.
Conclusion
This scoping review highlights the persistent challenges in Zambia’s cholera elimination efforts, despite the adoption of a Multisectoral Cholera Elimination Plan. The steady increase in cases and deaths over the years, coupled with the growing threat of climate change, necessitates a shift towards a decentralized, community-centric approach to cholera control.
Aligning health and WASH investments, leveraging oral cholera vaccines, and enhancing climate-resilient WASH infrastructure are crucial steps forward. Strengthening surveillance, reporting, and research efforts will also be vital in informing the next iteration of Zambia’s National Cholera Control Plan and guiding similar efforts in the region.
By addressing the persistent challenges and adopting evidence-based strategies, Zambia can make significant strides towards controlling and eventually eliminating cholera, contributing to the global efforts to end this deadly disease by 2030.
