Seroprevalence of West Nile Virus specific IgG and IgM antibodies in North-Western and Western provinces of Zambia

Background: West Nile Virus (WNV) infection has been reported worldwide, including in Africa but its existence in Zambia is unknown. Symptoms for the virus include headache, myalgia, arthralgia and rash.Objectives: This study aimed to determine the seroprevalence of WNV and its correlates.Methods: A cross sectional study was conducted in North-Western and Western provinces of Zambia. Samples were subjected to IgG and IgM antibodies testing against WNV. Logistic regression analyses were conducted to determine magnitudes of association.Results: A total of 3,625 of persons participated in the survey out of which 10.3% had WNV infection. Farmers were 20% (AOR=0.80; 95% CI [0.64, 0.99]) less likely to have infection compared to students. Meanwhile participants who lived in grass roofed houses were 2.97 (AOR=2.97; 95% CI [1.81, 4.88]) times more likely to be infected than those who lived in asbestos roofed houses. IRS was associated with reduced risk of infection (AOR=0.81; 95% CI [0.69, 0.94]). Travelling to Angola was associated with the infection [AOR=1.40; 95% CI [1.09, 1.81].Conclusion: Spraying houses with insecticide residual spray would minimize mosquito-man contact. Furthermore, surveillance at the border with Angola should be enhanced in order to reduce importation of the virus into the country.Keywords: Seroprevalence, West Wile Virus, Western province, North-Western province, Zambi

Cost-effectiveness analysis of introducing RDTs for malaria diagnosis as compared to microscopy and presumptive diagnosis in central and peripheral public health facilities in Ghana.

Cost-effectiveness information on where malaria rapid diagnostic tests (RDTs) should be introduced is limited. We developed incremental cost-effectiveness analyses with data from rural health facilities in Ghana with and without microscopy. In the latter, where diagnosis had been presumptive, the introduction of RDTs increased the proportion of patients who were correctly treated in relation to treatment with antimalarials, from 42% to 65% at an incremental societal cost of Ghana cedis (GHS)12.2 (US$8.3) per additional correctly treated patients. In the "microscopy setting" there was no advantage to replacing microscopy by RDT as the cost and proportion of correctly treated patients were similar. Results were sensitive to a decrease in the cost of RDTs, which cost GHS1.72 (US$1.17) per test at the time of the study and to improvements in adherence to negative tests that was just above 50% for both RDTs and microscopy

Seroprevalence of West Nile Virus specific IgG and IgM antibodies in North-Western and Western provinces of Zambia.

Background: West Nile Virus (WNV) infection has been reported worldwide, including in Africa but its existence in Zambia is unknown. Symptoms for the virus include headache, myalgia, arthralgia and rash. Objectives: This study aimed to determine the seroprevalence of WNV and its correlates. Methods: A cross sectional study was conducted in North-Western and Western provinces of Zambia. Samples were subjected to IgG and IgM antibodies testing against WNV. Logistic regression analyses were conducted to determine magnitudes of association. Results: A total of 3,625 of persons participated in the survey out of which 10.3% had WNV infection. Farmers were 20% (AOR=0.80; 95% CI [0.64, 0.99]) less likely to have infection compared to students. Meanwhile participants who lived in grass roofed houses were 2.97 (AOR=2.97; 95% CI [1.81, 4.88]) times more likely to be infected than those who lived in asbestos roofed houses. IRS was associated with reduced risk of infection (AOR=0.81; 95% CI [0.69, 0.94]). Travelling to Angola was associated with the infection [AOR=1.40; 95% CI [1.09, 1.81]. Conclusion: Spraying houses with insecticide residual spray would minimize mosquito-man contact. Furthermore, surveillance at the border with Angola should be enhanced in order to reduce importation of the virus into the country

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

Evaluating the efficacy, impact, and feasibility of community-based house screening as a complementary malaria control intervention in southern Africa : a study protocol for a household randomized trial

BACKGROUND : Concerted effort to control malaria has had a substantial impact on the transmission of the disease in the past two decades. In areas where reduced malaria transmission is being sustained through insecticide-based vector control interventions, primarily long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS), non-insecticidal complementary tools will likely be needed to push towards malaria elimination. Once interruption in local disease transmission is achieved, insecticide-based measures can be scaled down gradually and eventually phased out, saving on costs of sustaining control programs and mitigating any unintended negative health and environmental impacts posed by insecticides. These non-insecticidal methods could eventually replace insecticidal methods of vector control. House screening, a non-insecticidal method, has a long history in malaria control, but is still not widely adopted in subSaharan Africa. This study aims to add to the evidence base for this intervention in low transmission settings by assessing the efficacy, impact, and feasibility of house screening in areas where LLINs are conventionally used for malaria control. METHODS : A two-armed, household randomized clinical trial will be conducted in Mozambique, Zambia, and Zimbabwe to evaluate whether combined the use of house screens and LLINs affords better protection against clinical malaria in children between 6 months and 13 years compared to the sole use of LLINs. Eight hundred households will be enrolled in each study area, where 400 households will be randomly assigned the intervention, house screening, and LLINs while the control households will be provided with LLINs only. Clinical malaria incidence will be estimated by actively following up one child from each household for 6 months over the malaria transmission season. Crosssectional parasite prevalence will be estimated by testing all participating children for malaria parasites at the beginning and end of each transmission season using rapid diagnostic tests. CDC light traps and pyrethrum spray catches (PSC) will be used to sample adult mosquitoes and evaluate the impact of house screening on indoor mosquito density, species distribution, and sporozoite rates.The multi-country trial is funded as part of the AFRO-II project by the Global Environment Facility (GEF Project ID 4668) through the United Nations Environment Programme (UNEP) and the World Health Organization Regional Office for Africa (WHO-AFRO). Co-financing support is provided by the respective project countries for in-country activities and for technical support by icipe’s core funders including the UK’s Foreign, Commonwealth & Development Office (FCDO); the Swedish International Development Cooperation Agency (Sida); the Swiss Agency for Development and Cooperation (SDC); the Federal Democratic Republic of Ethiopia; and the Government of the Republic of Kenya. The views expressed herein do not necessarily reflect the official opinion of the donors.http://www.trialsjournal.comdm2022School of Health Systems and Public Health (SHSPH

Complete In Vitro Life Cycle of Trypanosoma congolense: Development of Genetic Tools

Trypanosoma congolense is a parasite responsible for severe disease of African livestock. Its life cycle is complex and divided into two phases, one in the tsetse fly vector and one in the bloodstream of the mammalian host. Molecular tools for gene function analyses in parasitic organisms are essential. Previous studies described the possibility of completing the entire T. congolense life cycle in vitro. However, the model showed major flaws including the absence of stable long-term culture of the infectious bloodstream forms, a laborious time-consuming period to perform the cycle and a lack of genetic tools. We therefore aimed to develop a standardized model convenient for genetic engineering. We succeeded in producing long-term cultures of all the developmental stages on long-term, to define all the differentiation steps and to finally complete the whole cycle in vitro. This improved model offers the opportunity to conduct phenotype analyses of genetically modified strains throughout the in vitro cycle and also during experimental infections

Underpinning Sustainable Vector Control through Informed Insecticide Resistance Management

Background: There has been rapid scale-up of malaria vector control in the last ten years. Both of the primary control strategies, long-lasting pyrethroid treated nets and indoor residual spraying, rely on the use of a limited number of insecticides. Insecticide resistance, as measured by bioassay, has rapidly increased in prevalence and has come to the forefront as an issue that needs to be addressed to maintain the sustainability of malaria control and the drive to elimination. Zambia’s programme reported high levels of resistance to the insecticides it used in 2010, and, as a result, increased its investment in resistance monitoring to support informed resistance management decisions. Methodology/Principal Findings: A country-wide survey on insecticide resistance in Zambian malaria vectors was performed using WHO bioassays to detect resistant phenotypes. Molecular techniques were used to detect target-site mutations and microarray to detect metabolic resistance mechanisms. Anopheles gambiae s.s. was resistant to pyrethroids,DDT and carbamates, with potential organophosphate resistance in one population. The resistant phenotypes were conferred by both target-site and metabolic mechanisms. Anopheles funestus s.s. was largely resistant to pyrethroids and carbamates, with potential resistance to DDT in two locations. The resistant phenotypes were conferred by elevated levels of cytochrome p450s. Conclusions/Significance: Currently, the Zambia National Malaria Control Centre is using these results to inform their vector control strategy. The methods employed here can serve as a template to all malaria-endemic countries striving to create a sustainable insecticide resistance management pla