CHOLERA EPIDEMIOLOGY IN ZAMBIA FROM 2000 TO 2010: IMPLICATIONS FOR IMPROVING CHOLERA PREVENTION AND CONTROL STRATEGIES IN THE COUNTRY.

OBJECTIVE: To review the cholera epidemiology in Zambia from 2000 to 2010 in order to highlight the key lessons learned. Based on our findings, we make recommendations for improving cholera prevention and control in country. DESIGN: Ten years descriptive cholera data was extracted from the national IDSR database and analysed. SETTING: The study was conducted in Zambia using national epidemiology data which were disaggregated by Province. SUBJECTS: None. RESULTS: Starting from 2003, there has been a progressive increase in yearly incidence of cholera in the country. In 2010, 6794 cases (500% increase compared to 2003) and 115 deaths (CFR 1.6%) of the disease were reported with Lusaka Province accounting for 85% of the total cases. Outbreaks start between epidemiological weeks 40 to 45 of the year and ends between weeks 20 to 25 of the following year (which corresponds to the Zambian rainy season). Outbreaks are largely confined to the peri-urban areas of Lusaka, Luapula, Southern and Copperbelt Provinces. CONCLUSION: In the last 10-20 years, the epidemiology of cholera in Zambia has changed; Laboratory confirmation of Vibrio cholerae in the country on a yearly basis in the last ten years suggests that the country is now endemic for cholera hence the need to review current cholera prevention and control strategies.

District specific correlates for hypertension in Kaoma and Kasama rural districts of Zambia.

INTRODUCTION: Hypertension a major risk factor for cardiovascular disease and is the most widely recognized modifiable risk factor for this disease. There is little information on the prevalence and risk factors for hypertension in Zambia, and in particular in rural areas of the country. In order to contribute to the existing global literature on hypertension, particularly in rural Zambia, this study was conducted to determine the prevalence of hypertension and its correlates in two rural districts of Zambia, namely Kaoma and Kasama. METHODS: A cross-sectional study using a modified World Health Organization (WHO) global non communicable diseases (NCD) surveillance initiative NCD-STEPwise approach was used. Proportions were compared using the Yates' corrected χ2 test, and a result yielding a p-value of less than 5% was considered significant. Bivariate and multivariate logistic regression analyses were conducted. Factors that were significantly associated with the outcome in bivariate analyses were considered in a multivariate logistic regression analysis using a backward variable selection method. Adjusted odds ratios (AOR) and their 95% confidence intervals (CI) were reported. RESULTS: In total, 895 participants from Kaoma and 1198 participants from Kasama took part in the surveys. Overall, 25.8% participants (27.5% male, 24.6% female; p=0.373) in Kaoma and 30.3% (31.3% male, 29.5% female; p=0.531) in Kasama were hypertensive. In Kaoma, age and BMI were independently associated with hypertension. Compared with participants aged 45 years or older, participants aged 25-34 years were 60% (AOR=0.40, 95% CI [0.21, 0.56]) less likely to be hypertensive. Participants with BMI <18.5 and 18.5-24.9 were 54% (AOR=0.46, 95% CI [0.30, 0.69]) and 31% (AOR=0.69, 95% CI [0.49, 0.98]) less likely to be hypertensive compared with participants with BMI ≥30. In Kasama, age, smoking and heart rate were significantly associated with hypertension in multivariate analysis. Participants 25-34 years were 49% (AOR=0.51, 95% CI [0.41, 0.65]) less likely to be hypertensive compared with participants 45 years or older. Compared with participants who were non-smokers, smokers were 21% (AOR=1.21, 95% CI [1.02, 1.45]) more likely to be hypertensive. Participants who had heart rate >90 beats/min were 59% (AOR=1.59, 95% CI [1.17, 2.16]) more likely to be hypertensive compared with participants who had heart rate 60-90 beats/min. CONCLUSIONS: The findings reveal that hypertension is prevalent among rural residents in Kaoma and Kasama, Zambia. The disease is highly associated with age, BMI, smoking and heart rate. Efficient preventive strategies are needed to halt the growing trend of non-communicable diseases through the control of risk factors highlighted in this study.

Significant decline in lymphatic filariasis associated with nationwide scale-up of insecticide-treated nets in Zambia.

Lymphatic filariasis (LF) is a mosquito-borne disease, broadly endemic in Zambia, and is targeted for elimination by mass drug administration (MDA) of albendazole and diethylcarbamazine citrate (DEC) to at-risk populations. Anopheline mosquitoes are primary vectors of LF in Africa, and it is possible that the significant scale-up of malaria vector control over the past decade may have also impacted LF transmission, and contributed to a decrease in prevalence in Zambia. We therefore aimed to examine the putative association between decreasing LF prevalence and increasing coverage of insecticide-treated mosquito nets (ITNs) for malaria vector control, by comparing LF mapping data collected between 2003-2005 and 2009-2011 to LF sentinel site prevalence data collected between 2012 and 2014, before any anti-LF MDA was started. The coverage of ITNs for malaria was quantified and compared for each site in relation to the dynamics of LF. We found a significant decrease in LF prevalence from the years 2003-2005 (11.5% CI95 6.6; 16.4) to 2012-2014 (0.6% CI95 0.03; 1.1); at the same time, there was a significant scale-up of ITNs across the country from 0.2% (CI95 0.0; 0.3) to 76.1% (CI95 71.4; 80.7) respectively. The creation and comparison of two linear models demonstrated that the geographical and temporal variation in ITN coverage was a better predictor of LF prevalence than year alone. Whilst a causal relationship between LF prevalence and ITN coverage cannot be proved, we propose that the scale-up of ITNs has helped to control Anopheles mosquito populations, which have in turn impacted on LF transmission significantly before the scale-up of MDA. This putative synergy with vector control has helped to put Zambia on track to meet national and global goals of LF elimination by 2020.