Geographical and temporal variation in reduction of malaria infection among children under 5 years of age throughout Nigeria

A Bayesian spatio-temporal framework to assess the effect of seasonal malaria chemoprevention on children under 5 years in Cameroon from 2016 to 2021 using routine data

BACKGROUND

Malaria affects millions of Cameroonian children under 5 years of age living in the North and Far North regions. These regions bear the greatest burden, particularly for children under 5 years of age. To reduce the burden of disease in these regions, Cameroon adopted the Seasonal Malaria Chemoprevention (SMC) in 2016 and has implemented it each year since its adoption. However, no previous studies have systematically assessed the effects of this intervention in Cameroon. It is important to understand its effect and whether its implementation could be improved. This study aimed to assess the effect of SMC in Cameroon during the period 2016-2021 on malaria morbidity in children under 5 years of age using routine data.

METHODS

Data on malaria cases were extracted from the Cameroon Health Monitoring Information System (HMIS) from January 1, 2011, to December 31, 2021. Health facilities report these data monthly on a single platform, the District Health Information System version 2 (DHIS2). Thus, a controlled interrupted time-series model in a Bayesian framework was used to evaluate the effects of the SMC on malaria morbidity.

RESULTS

SMC implementation was associated with a reduction in the incidence of uncomplicated malaria cases during the high-transmission periods from 2016 to 2021. Regarding the incidence of severe malaria during the high-transmission period, a reduction was found over the period 2016-2019. The highest reduction was registered during the second year of implementation in 2017:15% (95% Credible Interval, 10-19) of uncomplicated malaria cases and 51% (47-54) of confirmed severe malaria cases.

CONCLUSION

The addition of SMC to the malaria intervention package in Cameroon decreased the incidence of uncomplicated and severe malaria among children under 5 years of age. Based on these findings, this study supports the wide implementation of SMC to reduce the malaria burden in Cameroon as well as the use of routine malaria data to monitor the efficiency of the strategy in a timely manner.

Malaria parasite density and detailed qualitative microscopy enhances large-scale profiling of infection endemicity in Nigeria

With global progress towards malaria reduction stalling, further analysis of epidemiology is required, particularly in countries with the highest burden. National surveys have mostly analysed infection prevalence, while large-scale data on parasite density and different developmental forms rarely available. In Nigeria, the country with the largest burden globally, blood slide microscopy of children up to 5 years of age was conducted in the 2018 National Demographic and Health Survey, and parasite prevalence previously reported. In the current study, malaria parasite density measurements are reported and analysed for 7783 of the children sampled across the 36 states within the six geopolitical zones of the country. Asexual and sexual stages, and infections with different malaria parasite species are analysed. Across all states of Nigeria, there was a positive correlation between mean asexual parasite density within infected individuals and prevalence of infection in the community (Spearman's rho = 0.39, P = 0.02). Asexual parasite densities were highest in the northern geopolitical zones (geometric means > 2000 μL-1), extending the evidence of exceptionally high infection burden in many areas. Sexual parasite prevalence in each state was highly correlated with asexual parasite prevalence (Spearman's rho = 0.70, P < 0.001), although sexual parasite densities were low (geometric means < 100 μL-1 in all zones). Infants had lower parasite densities than children above 1 year of age, but there were no differences between male and female children. Most infections were of P. falciparum, which had higher asexual densities but lower sexual parasite densities than P. malariae or P. ovale mono-infections. However, mixed species infections had the highest asexual parasite densities. It is recommended that future large surveys in high burden countries measure parasite densities as well as developmental stages and species, to improve the quality of malaria epidemiology and tracking of future changes.

Lessons from Nigeria's Adaptation of Global Health Initiatives during the COVID-19 Pandemic

Nigeria receives funds from several global health initiatives that are aimed at addressing elevated risks and overall burden of infectious disease outbreaks. These funds include the Global Fund to Fight AIDS, Tuberculosis and Malaria; US President's Emergency Plan for AIDS Relief; US President's Malaria Initiative; and Global Polio Eradication Initiative. These initiatives have contributed to a substantial reduction in illness and death from HIV, tuberculosis, malaria, and polio. However, Nigeria has experienced mixed success with leveraging the capacities built through these donor-funded vertical programs to respond to new health threats. This report describes experiences using resources from vertical disease programs by the Nigeria Centre for Disease Control in response to the 2014-2016 Ebola outbreak in West Africa and the COVID-19 pandemic. Integrating resources from different disease programs with government-led systems and institutions will improve responses to endemic outbreaks and preparedness for future pandemics in Nigeria.

Use of insecticide treated nets in children under five and children of school age in Nigeria: Evidence from a secondary data analysis of demographic health survey

Background and objective

Use of insecticide treated nets (ITN), one of the most cost-effective malaria interventions contributes to malaria cases averted and reduction in child mortality. We explored the use of ITN in children under five (CU5) and children of school age to understand factors contributing to ITN use.

Methods

A cross-sectional study analyzed 2018 Nigeria Demographic and Health Survey data. The outcome variable was CU5 or children of school age who slept under ITN the night before the survey. Independent variables include child sex, head of household’s sex, place of residence, state, household owning radio and television, number of household members, wealth quintile, years since ITN was obtained and level of malaria endemicity. Multi-level logistic regression model was used to access factors associated with ITN use among children.

Results

In total, 32,087 CU5 and 54,692 children of school age were examined with 74.3% of CU5 and 57.8% of children of school age using ITN the night before the survey. While seven states had more than 80% of CU5 who used ITN, only one state had over 80% of school children who used ITN. ITN use in CU5 is associated with living in rural area (aOR = 1.20, 95% CI 1.14 to 1.26) and residing in meso endemic area (aOR = 3.1, 95% CI 2.89 to 3.54). While In children of school age, use of ITN was associated with female headed households (aOR = 1.14, 95% CI 1.09 to 1.19), meso (aOR = 3.17, 95% CI 2.89 to 3.47) and hyper (aOR = 14.9, 95% CI 12.99 to 17.07) endemic areas. Children residing in larger households were less likely to use ITN.

Conclusions

This study demonstrated increased use of ITN in CU5 from poor households and children living in rural and malaria endemic areas. Findings provide some policy recommendations for increasing ITN use in school children.

Sociodemographic factors associated with the use of insecticide treated nets among under-fives in Nigeria: Evidence from a national survey

Insecticide treated nets (ITN) are effective in malaria prevention; however, they remain underutilized among children. A secondary analysis of the 2018 Nigeria-Demographic and Health Survey including logistic regression was conducted to determine factors influencing ITN use among under-fives (U5s). Overall, 22,954 (72.4%) slept under ITN the night before the survey. Children <4 years and those in the northern regions had significantly higher odds of using ITN, as did those from households with ≤6 members and those from the lowest to middle wealth quintiles. However, among those households recorded as having "universal ITN coverage" i.e. at least one net between two persons, children <3 years, those from the rural northern regions and those from the lowest wealth category had significantly higher odds of using ITN. Interventions to improve ITN use by U5s should be intensified among households with larger size, those from the highest wealth quintiles and residents in southern Nigeria.

Drivers of long-lasting insecticide-treated net utilisation and parasitaemia among under-five children in 13 States with high malaria burden in Nigeria

BACKGROUND

Although Nigeria has made some progress in malaria control, there are variations across States. We investigated the factors associated with utilisation of long-lasting insecticide-treated net (LLIN) and parasitaemia among under-five children in 13 States with high malaria burden.

METHOD

Data from the 2015 Nigeria Malaria Indicator Survey and 2018 Demographic and Health Survey were obtained and analysed. The 2015 and 2018 data were compared to identify States with increase or reduction in parasitaemia. Analysis was done for all the 13 study States; four States with increased parasitaemia and nine States with reduction. Random-effects logit models were fitted to identify independent predictors of LLIN utilisation and parasitaemia.

RESULTS

LLIN was used by 53.4% of 2844 children, while parasitaemia prevalence was 26.4% in 2018. Grandchildren (AOR = 5.35, CI: 1.09-26.19) were more likely to use LLIN while other relatives (AOR = 0.33, CI: 0.11-0.94) were less likely compared to children of household-heads. LLIN use was more common in children whose mother opined that only weak children could die from malaria (AOR = 1.83, CI: 1.10-3.10). Children whose mothers obtained net from antenatal or immunisation clinics (AOR = 5.30, CI: 2.32-12.14) and campaigns (AOR = 1.77, CI: 1.03-3.04) were also more likely to use LLIN. In contrast, LLIN utilisation was less likely among children in female-headed households (AOR = 0.51, CI: 0.27-0.99) and those in poor-quality houses (AOR = 0.25, CI: 0.09-0.72). Children aged 24-59 months compared to 0-11 months (AOR = 1.78, CI: 1.28-2.48), those in whom fever was reported (AOR = 1.31, CI: 1.06-1.63) and children of uneducated women (AOR = 1.89, CI: 1.32-2.70) were more likely to have parasitaemia. The likelihood of parasitaemia was higher among children from poor households compared to the rich (AOR = 2.06, CI: 1.24-3.42). The odds of parasitaemia were 98% higher among rural children (AOR = 1.98, CI: 1.37-2.87).

CONCLUSION

The key drivers of LLIN utilisation were source of net and socioeconomic characteristics. The latter was also a key factor associated with parasitaemia. These should be targeted as part of integrated malaria elimination efforts.

Mutations in Pfcrt and Pfmdr1 genes of Plasmodium falciparum isolates from two sites in Northcentral and Southwest Nigeria

The ability of malaria parasites to develop resistance to antimalarial drugs has made it necessary to continuously survey malaria parasite populations for resistance markers. Mutations in specific malaria parasite genes confer resistance to antimalarial drugs. The study compared mutations in Pfcrt and Pfmdr1 genes of P. falciparum from two ecologically different areas of Nigeria. Plasmodium falciparum dried blood spots collected from New Bussa (Northcentral Nigeria) and Ijede (Southwest Nigeria) were analysed by PCR-RFLP for Pfcrt, K76 T, Pfmdr1, N86Y and Y184F mutations. Pfmdr1 copy number was determined by quantitative-PCR. A total of 145 blood spots [Ijede = 55; New Bussa = 90 blood spots] were analysed, but Pfcrt gene was successfully amplified in 144 samples while Pfmdr1 was amplified in 132 samples. Overall, prevalence of mutant forms of Pfcrt 76 T,Pfmdr1 86Y and 184F were 74.3% (95% CI: 66.4-81.2%), 18.2% (95% CI: 12.0-25.8%) and 35.6% (95% CI: 27.5-44.4%). The frequency of Pfcrt 76 T was similar in both study sites [Ijede: 81.8% (95%CI: 69.1-90.9%); New Bussa: 69.7% (95%CI: 59.0-79.0), p = 0.105]. However, the frequencies of Pfmdr1 86Y and 184F were significantly higher in Ijede (28.3% and 62.3%) than in New Bussa (11.4% and 17.7%), respectively (P < 0.05). Eight parasite genotypes based on three codons of the two genes were identified. The most frequent genotype was TNY 53(40.5%) while the least was KYF 1 (0.8%). The most frequent genotype in Ijede and New Bussa were TNF 18(34.0%) and TNY 40 (51.3%) respectively. The frequency of wild strain KNF in Ijede and New Bussa were 3 (5.7%) and 18 (23.1%), respectively. The distribution of the genotypes differed significantly by location. The genotypes with more than two or more mutations were more in Ijede 32 (60.4%) than in New Bussa 16 (20.5%) (p < 0.001). Amplification of Pfmdr1 copy number was not observed in the two study sites. The prevalence of Pfcrt 76 T was similar in both locations while Pfmdr1 86Y and 184F differed in both locations. Single nucleotide polymorphisms in the three codons assessed were more in Ijede than in New Bussa.