Zambia - High priority areas / Hotspots

SUMMARY OF KEY FINDINGS

Cholera burden and dynamics

• From 1999 to 2018, 74% of the cases were notified by Lusaka Province (the city played a role in cholera amplification and diffusion) ;
• Main cholera foci were reported in the peri-urban areas of Lusaka and Copperbelt Provinces and around waterbodies in Central, Luapula, Northern and Southern Provinces along the borders with DRC, Tanzania and Zimbabwe.
• Outbreaks were first detected either in the capital Lusaka or northern provinces.
• Marked seasonality with outbreak onset between September and November (end of dry season) and outbreak end between May and June (end of the rainy season).
• Cross-border outbreaks in fishing camps and border districts mainly along the Zimbabwe, Tanzania and DRC borders.

Cholera hotspots

• Cholera foci were located at:

–the periphery of urban areas (Lusaka, Ndola and Kitwe)

–Along the border with the DRC and Tanzania around the Mweru and Tanganyika Lakes

–In the center of the country, around the Lukanga swamp area

–Along the border with Zimbabwe around the Kafue Flat swamp area and Kariba Lake

Risk factors

• Population movement

–70% of fishermen are seasonal immigrants, a highly mobile population throughout the country originally from the northern provinces (Bemba ethnic group). Accelerated migration of fishermen and fish tradesmen within the country and across borders during the fishing season.

–Congolese refugee influx in Chienge and Nchelenge border districts (Luapula province).

–Seasonal labor, trade and frequent migration with neighboring countries such as DRC, Zimbabwe, and to a less extend Tanzania, Malawi and Angola, increased the risk of cholera upsurge in border districts.

• Environmental factors (fishing camps)

–Outbreaks of cholera concentrated in the fishing camps and villages around waterbodies in northern, central and southern provinces (Lake Mweru, Lake Tanganyika, Lake Kariba, Lukanga and the Kafue Flat swamps).

–Fishermen and their families spend several weeks every year in fishing camps and use surface waters for all domestic needs including drinking and sanitation.

–In 2016, water was found to be contaminated with Vibrio cholerae in the Lukanga fishing camp of Kapiri Moshi District (Central Province).

• Structural and environmental factors (Lusaka western suburbs)

–The population mostly uses ordinary pit latrines and relies on shallow wells and boreholes.

–Lusaka is partially built on karstic landscape combined with a shallow water table.

–The environmental conditions combined with pit latrines and poor storm water drainage increased the risk of flooding, resulting in large-scale contamination of water points.

• In 2018, one third of the 3,303 water samples tested by the Food and Drug Control Laboratory had fecal contamination.
• Lack of latrines (45% of the population) and drainage networks statistically associated with increased cholera incidence.
• Demonstrated association between rainfall and cholera incidence.
• High-risk practices

–One quarter of the rural population resorts to open defecation, and sharing a latrine was considered as a high-risk behavior in Lusaka.

–Two thirds of households in Zambia do not treat water prior to drinking.

–Less than 10% of the caregivers were able to identify all critical times for handwashing, while in Lusaka, handwashing with soap or the presence of soap was a protective factor.

• Individual risk factors

–Contact with a cholera patient, low cholera immunity and weakened immune system due to HIV or AIDS.