Adapting to a changing climate: indigenous biotic rainfall forecasting in Western Zambia.

Forecasting rainfall at the local scale to inform farm-level decisions is complex and it remains an unresolved problem with dire implications for food security. Here, we examine indigenous knowledge forecasting systems used by smallholder farmers in Maondo Agriculture Camp (MAC) of Sesheke District in the Western Province of Zambia to increase their climate change adaptive capacity at the farm level. We adopted a qualitative approach that uses an exploratory-descriptive design. We then used purposive sampling, a non-probability methodological approach, to choose respondents. We applied semi-structured interviews and questionnaires as data collection tools and examined the data using thematic content analysis. We found that > 50% of small-scale farmers receive forecasts produced by the Zambia Meteorological Department (ZMD) through stakeholders' meetings. Farmers who do not receive ZMD forecasts depend on indigenous knowledge systems. Results further indicate that farmers in the MAC combine several indicators to predict rainfall. Prominent among them include plants, weather-related parameters, and astrological indicators. A cursory inspection of these rainfall predictors revealed several points specifically highlighting three salient thematic contents, i.e. biological, meteorological, and astrological. Results further showed that both conventional science and indigenous knowledge used to forecast rainfall have strengths and weaknesses. We, therefore, conclude that the integration of the two methods has the potential to significantly improve rainfall forecasts and ultimately agricultural productivity at the farm level.

An unusually long Rift valley fever inter-epizootic period in Zambia: Evidence for enzootic virus circulation and risk for disease outbreak.

Rift valley fever (RVF) is a mosquito-borne disease of animals and humans. Although RVF outbreaks are usually reported at 5-15-year intervals in sub-Saharan Africa, Zambia has experienced an unusually long inter-epizootic/-epidemic period of more than three decades. However, serological evidence of RVF virus (RVFV) infection in domestic ruminants during this period underscores the need for comprehensive investigation of the mechanisms of virus perpetuation and disease emergence. Mosquitoes (n = 16,778) captured from eight of the ten provinces of Zambia between April 2014 and May 2019 were pooled (n = 961) and screened for RVFV genome by a pan-phlebo RT-PCR assay. Aedes mosquito pools (n = 85) were further screened by nested RT-PCR assay. Sera from sheep (n = 13), goats (n = 259) and wild ungulates (n = 285) were screened for RVFV antibodies by ELISA while genome detection in pooled sera (n = 276) from domestic (n = 248) and wild ungulates (n = 37) was performed by real-time RT-PCR assay. To examine the association between the long inter-epizootic period and climatic variables, we examined El Niño-Southern Oscillation indices, precipitation anomalies, and normalized difference vegetation index. We then derived RVF risk maps by exploring climatic variables that would favor emergence of primary RVFV vectors. While no RVFV genome could be detected in pooled mosquito and serum samples, seroprevalence was significantly high (OR = 8.13, 95% CI [4.63-14.25]) in wild ungulates (33.7%; 96/285) compared to domestic ruminants (5.6%; 16/272). Retrospective analysis of RVF epizootics in Zambia showed a positive correlation between anomalous precipitation (La Niña) and disease emergence. On risk mapping, whilst northern and eastern parts of the country were at high risk, domestic ruminant population density was low (< 21 animals/km2) in these areas compared to low risk areas (>21 animals/km2). Besides evidence of silent circulation of RVFV and the risk of disease emergence in some areas, wildlife may play a role in the maintenance of RVFV in Zambia.