Coverage, determinants of use and repurposing of long-lasting insecticidal nets two years after a mass distribution in Lihir Islands, Papua New Guinea: a cross-sectional study

Human and entomological determinants of malaria transmission in the Lihir Islands of Papua New Guinea: A cross-sectional study

BACKGROUND

The Lihir Islands of Papua New Guinea, located in an area with high burden of malaria and hosting a large mining operation, offer a unique opportunity to study transmission. There, we investigated human and vector factors influencing malaria transmission.

METHODS

In 2019, a cross-sectional study was conducted on 2,914 individuals assessing malaria prevalence through rapid diagnostic tests (RDT), microscopy, and quantitative PCR (qPCR). A logistic regression analysis identified infection-associated factors. Anopheles species distribution, biting behaviours, and sporozoite carriage were assessed through human landing catches and larval surveys.

RESULTS

Overall malaria prevalence (any species) was 3.6% by RDT, 4.5% by microscopy, and 15.0% by qPCR. P. vivax accounted for 37.1% of infections, P. falciparum for 34.6%, P. malariae for 3.0%, P. ovale 0.2%, and mixed infections for 24.5%. Prevalence (qPCR) varied across geographic areas, from 8.5% in the mine-impacted zone (MIZ) to 27.0% in the non-MIZ. Other factors independently associated with infection risk included cohabiting with an infected individual (aOR = 1.94, 95%CI: 1.56-2.42), and residing in traditional housing (aOR = 1.65, 95%CI: 1.21-2.25). Children had double the infection risk compared to adults, and the use of long-lasting insecticidal-treated nets did not decrease risk of infection. An. punctulatus was the major vector in one of the four geographical areas; while An. farauti was predominant in the rest of them, both with an early biting behaviour but with different biting intensities by geographical area. Entomological inoculation rates ranged from 26.9 (95%CI: 12.3-45.2) infective bites per person-year in the MIZ to 441.3 (95%CI: 315.7-572.1) in the non-MIZ.

CONCLUSIONS

Malaria transmission and infection was lower in the MIZ compared to other areas. Measures focusing on at-risk groups, including vector-control and transmission interruption methods, could be taken into account by the mine and the healthcare authorities to reduce malaria burden outside the MIZ.

The challenge of improving long-lasting insecticidal nets coverage on Bioko Island: using data to adapt distribution strategies

BACKGROUND

Since 2015, malaria vector control on Bioko Island has relied heavily upon long-lasting insecticidal nets (LLIN) to complement other interventions. Despite significant resources utilised, however, achieving and maintaining high coverage has been elusive. Here, core LLIN indicators were used to assess and redefine distribution strategies.

METHODS

LLIN indicators were estimated for Bioko Island between 2015 and 2022 using a 1x1 km grid of areas. The way these indicators interacted was used to critically assess coverage targets. Particular attention was paid to spatial heterogeneity and to differences between urban Malabo, the capital, and the rural periphery.

RESULTS

LLIN coverage according to all indicators varied substantially across areas, decreased significantly soon after mass distribution campaigns (MDC) and, with few exceptions, remained consistently below the recommended target. Use was strongly correlated with population access, particularly in Malabo. After a change in strategy in Malabo from MDC to fixed distribution points, use-to-access showed significant improvement, indicating those who obtained their nets from these sources were more likely to keep them and use them. Moreover, their use rates were significantly higher than those of whom sourced their nets elsewhere.

CONCLUSIONS

Striking a better balance between LLIN distribution efficiency and coverage represents a major challenge as LLIN retention and use rates remain low despite high access resulting from MDC. The cost-benefit of fixed distribution points in Malabo revealed significant advantages, offering a viable alternative for ensuring access to LLINs to those who use them.

Knowledge, attitude and practice levels regarding malaria among the Semai sub-ethnic indigenous Orang Asli communities in Pahang, Peninsular Malaysia: a stepping stone towards the prevention of human malaria re-establishment

BACKGROUND

In Malaysia, despite a decline in cases, malaria remains a major public health concern, especially among the vulnerable indigenous people (i.e. Orang Asli) in remote areas. Effective preventive and control measures require an evidence-based understanding of their knowledge, attitudes, and practices (KAP) regarding malaria. This study aimed to evaluate the KAP regarding malaria in an indigenous settlement in Peninsular Malaysia.

METHODS

A household-based cross-sectional study was conducted in March 2024 in six Semai sub-ethnic indigenous villages in Pos Lenjang, Kuala Lipis, Pahang. A structured questionnaire was administered to randomly selected individuals (≥ 12 years old) to collect data on sociodemographic characteristics and KAP. Data were analysed using descriptive statistics and predictors of KAP were determined using logistic regression. A p-value less than 0.05 was considered statistically significant.

RESULTS

A total of 267 individuals from 160 households were interviewed. Nearly half had good knowledge (49.4%) and positive attitudes (54.3%) towards malaria, with high practice scores for prevention and control (83.1%). Multivariate logistic regression analysis showed higher odds of good knowledge in those aged 40-59 years (adjusted odd ratio [aOR] = 6.90, p = 0.034), with primary (aOR = 2.67, p = 0.015) or secondary education (aOR = 2.75, p = 0.019), and with previous malaria history (aOR = 5.14, p < 0.001). Higher odds of a good attitude were found in those with secondary education (aOR = 4.05, p < 0.001) and previous malaria history (aOR = 2.74, p = 0.017). Lower odds were observed for the unemployed (aOR = 0.25, p = 0.018) and those collecting forest products (aOR = 0.25, p = 0.049) for attitude and practice, respectively.

DISCUSSION

The overall practice level on malaria prevention was high among the Semai Orang Asli in Pahang. However, to ensure sustainability, the low levels of knowledge and attitude regarding malaria must be strengthened through increased health education and continuous community engagement.

Expanded roles of community health workers to sustain malaria services in the Asia-Pacific: A landscaping survey

Malaria Community Health Workers (CHWs) in the Greater Mekong Subregion (GMS) are an important component of malaria elimination efforts. As malaria declines with intensified efforts to eliminate by 2030, expanding their roles beyond malaria could help to sustain funding and provision of malaria services at the community level. Evidence of how programmes have implemented and managed CHWs performing both malaria and non-malaria roles across the Asia-Pacific region can provide insight into the viability of this strategy. A short survey was distributed to national malaria programmes and implementing organizations in the Asia-Pacific region in 2021-2022. The survey identified CHW programmes in the region, and collected information on malaria and non-malarial services provided by CHWs, characteristics of each identified programme, and the impact of COVID-19 on these programmes. 35 survey responses identified 28 programmes in 14 countries. The most frequently reported services provided by malaria CHWs were health promotion and education for malaria (13/14 countries) and other diseases (11/14); and COVID-19 related activities (10/14). Most programmes were financed wholly through donor funding (18/28 programmes), or donor plus government funding (6/28). Of 21 programmes which performed programme evaluation, only 2 evaluated their impacts on diseases beyond malaria. Declining donor funding, and COVID-19 related travel and activity restrictions were identified as implementation challenges. CHWs across the Asia Pacific provide a range of health services with malaria and are resilient under changing public health landscapes such as the COVID-19 pandemic. Further investigation into the impact of additional roles on malaria CHW performance and targeted health outcomes is needed to verify the benefits and feasibility of role expansion. As the GMS approaches elimination, and funding declines, verifying the cost effectiveness of malaria CHW programmes will be vital to persuade donors and countries to invest in malaria CHWs to sustain malaria services, and strengthen community-based health care.

Long-Lasting Insecticidal Net Coverage and Utilization in Burla Town of Sambalpur District: A Cross-Sectional Study

Background Vector-borne diseases continue to significantly contribute to mortality and morbidity, especially in developing nations. Vector management is a key pillar in combating these diseases, and long-lasting insecticidal nets (LLINs) are cost-effective tools. The Government of India, under the National Vector Borne Disease Control Programme (NVBDCP), has distributed LLINs for free to increase coverage and utilization. This study aims to estimate the coverage and utilization of LLINs in Burla town. Method This cross-sectional study was conducted from October to December 2022 in Burla town of Sambalpur in Odisha, India. The estimated sample size was 510 households, assuming 50% coverage. Multi-stage cluster sampling was adopted to select the Anganwadi centers and households. A pretested questionnaire was utilized for data collection by trained personnel through Epicollect5 (Centre for Genomic Pathogen Surveillance, Oxford, UK). Logistic regression was used to identify predictors for LLIN usage. Results The survey covered 516 households with 2,541 individuals and 1,165 nets. Household-level coverage was 94.2%, and regular utilization was 45.74%. Skin reactions (35.7%) were the most common reason for non-usage, followed by low mosquito density (12%). Logistic regression showed that the number of rooms (adjusted odds ratio (AOR) = 0.663, p = 0.012), number of bed nets (AOR = 2.757, p < 0.001), knowledge of malaria (AOR = 2.92, p = 0.04), adopting other measures for mosquito control (AOR = 0.295, p < 0.001), and washing the net (AOR = 1.92, p = 0.028) significantly predicted sleeping under mosquito net. Conclusion Our study has depicted high coverage of LLINs in Burla town, but utilization needs further improvement. Counseling regarding proper use can decrease the skin reactions responsible for non-usage. Regular health education programs are required to emphasize the benefits of LLIN use, along with regular monitoring and supervision.

The challenge of improving long-lasting insecticidal nets coverage on Bioko Island: using data to adapt distribution strategies

Background

Since 2015, malaria vector control on Bioko Island has relied heavily upon long-lasting insecticidal nets (LLIN) to complement other interventions. Despite significant resources utilised, however, achieving and maintaining high coverage has been elusive. Here, core LLIN indicators were used to assess and redefine distribution strategies.

Methods

LLIN indicators were estimated for Bioko Island between 2015 and 2022 using a 1×1 km grid of areas. The way these indicators interacted was used to critically assess coverage targets. Particular attention was paid to spatial heterogeneity and to differences between urban Malabo, the capital, and the rural periphery.

Results

LLIN coverage according to all indicators varied substantially across areas, decreased significantly soon after mass distribution campaigns (MDC) and, with few exceptions, remained consistently below the recommended target. Use was strongly correlated with population access, particularly in Malabo. After a change in strategy in Malabo from MDC to fixed distribution points, use-to-access showed significant improvement, indicating those who obtained their nets from these sources were more likely to keep them and use them. Moreover, their use rates were significantly higher than those of whom sourced their nets elsewhere.

Conclusions

Striking a better balance between LLIN distribution efficiency and coverage represents a major challenge as LLIN retention and use rates remain low despite high access resulting from MDC. The cost benefit of fixed distribution points in Malabo was deemed significant, providing a viable alternative for guaranteeing access to LLINs to those who use them.

Challenges of proper disposal of old long-lasting insecticidal nets and its alternative uses in rural south-eastern Tanzania

INTRODUCTION

Insecticide-treated nets (ITNs), specifically long-lasting insecticidal nets (LLINs), are the most commonly used, scalable, and cost-effective tools for controlling malaria transmission in sub-Saharan Africa. However, the multiple alternative uses of retired LLINs have been associated with poor disposal practices. The World Health Organization (WHO) has provided guidelines and recommendations for the proper management of worn-out LLINs. This study assessed the existing alternative uses and disposal practices of old LLINs.

METHODS

An explanatory sequential mixed-methods approach was used to assess LLINs existing alternative uses, disposal practices, knowledge, and perceptions regarding WHO recommendations on proper disposal of old LLINs among stakeholders in Kilombero and Ulanga districts, south-eastern Tanzania. A survey questionnaire was administered to 384 participants. Furthermore, the study employed focus group discussions (FGD) and key informant interviews (KII) to elucidate responses regarding existing disposal practices, associated challenges, and alternative uses of LLINs. The insights derived from both study components were subsequently used for inferential analysis.

RESULTS

The major challenge influencing the proper disposal of LLINs was limited awareness of how to properly dispose of them. Of the 384 people surveyed, 97.0% were not aware of the WHO recommendations for the proper disposal of old LLINs. All key informants were unaware of the WHO guidelines for proper disposal of old LLINs. The common methods used to dispose of LLINs were burning (30.7%), disposing them into garbage pits (14.8%), and alternative uses (12.2%). Of the 239 respondents with LLINs, 41.0% had alternative use, while 59.0% had no alternative use. The common alternative uses were ropes for tying or covering items (20.9%), garden fencing (7.5%), chicken coops (5.0%), and 7.5% for other minor alternative uses.

CONCLUSION

Strengthening awareness and education on proper LLIN disposal practices among community members and key stakeholders is essential for enhancing malaria control efforts and preventing environmental pollution.

A cross-sectional study to ascertain malaria prevalence among asymptomatic travellers arriving on the Lihir Group of Islands, Papua New Guinea: implications for elimination efforts

BACKGROUND

The Lihir Islands of Papua New Guinea host a mining operation that has resulted in a mine-impacted zone (MIZ) with reduced malaria transmission and a substantial influx of mine employees, informal cross-country traders, returning locals, and visitors. Prevalence of malaria parasites was assessed in travellers arriving on the Lihir Group of Islands to evaluate the risk of parasite importation.

METHODS

In 2018, a cross-sectional study at the airport and main wharf was conducted, targeting asymptomatic travellers who had been away from Lihir for at least 12 days. Microscopy, rapid diagnostic tests (RDTs), and quantitative PCR (qPCR) were used to determine Plasmodium parasite prevalence, employing logistic regression models to identify factors associated with qPCR positivity.

RESULTS

398 travellers arriving by plane and 402 arriving by boat were included. Both cohorts were significantly different. Mean age among travellers arriving by plane was 40.1 years (SD ± 10.1), 93% were male and 96% were employed at the mine. In contrast, among travellers arriving by boat, the mean age was 31.7 years (SD ± 14.0), 68% were male and 36% were employed at the mine. The prevalence of malaria infection among travellers arriving by plane was 1% by RDT and microscopy, and increased to 5% by qPCR. In contrast, those arriving by boat showed a prevalence of 8% by RDT and microscopy, and 17% by qPCR. Risk factors for infection were arriving by boat (OR 4.2; 95%CI 2.45,7.21), arriving from nearby provinces with high malaria incidence (OR 5.02; 95%CI 1.80, 14.01), and having been away from Lihir for 91 days or more (OR 4.15; 95%CI 2.58, 6.66). Being mine worker staying at the mine accommodation was related with less infection risk (OR 0.24; 95% CI 0.14, 0.43); while Lihirian residents returning from a trip, VFRs, or people with trading unrelated to mining had higher risks (p = 0.0066).

CONCLUSIONS

Travellers arriving by boat faced increased risk of malaria infection than those arriving by plane. This subpopulation poses an import risk to the MIZ and the rest of Lihir Islands. Screening of high-risk groups at wharfs, and collaboration with nearby Islands, could sustain reduced transmission and facilitate malaria elimination strategies.

An evaluation of LLIN ownership, access, and use during the Magude project in southern Mozambique

The Magude Project assessed the feasibly of eliminating malaria in a low transmission setting in southern Mozambique using a package of interventions. This study measured the ownership, access and use of long-lasting insecticide treated nets (LLINs) and inequalities in these indicators across household wealth, size and population subgroups, to understand the protection that LLINs provided during the project. Data were obtained from various household surveys. At least 31% of the nets distributed during the 2014 and 2017 campaigns were lost during the first year post-distribution. Most nets (77.1%) present in the district were Olyset Nets. LLIN access never exceeded 76.3% and use varied seasonally between 40% and 76.4%. LLIN access limited LLIN use during the project, especially during the high transmission season. LLIN ownership, access and use were lower in harder-to-reach localities, in poorer and larger households. Children and women below 30 had poorer access to LLINs than the overall population. Net use was lowest among school-aged children and young adults, especially among young males, and highest in children under 5, pregnant women, in older adults and in households that received indoor residual spraying (IRS). This study revealed that LLIN mass-distribution campaigns alone are not sufficient to achieve the high level of net protection needed during elimination programs and that reviewing the LLIN allocation scheme, top-up distributions and/or community engagement campaigns is needed, also to reduce inequalities in populations' access to LLINs.

Collateral Effects of Insecticide-Treated Nets on Human and Environmental Safety in an Epidemiological Model for Malaria with Human Risk Perception

Malaria remains a major health problem in many parts of the world, including Sub-Saharan Africa. Insecticide-treated nets, in combination with other control measures, have been effective in reducing malaria incidence over the past two decades. Nevertheless, there are concerns about improper handling and misuse of nets, producing possible health effects from intoxication and collateral environmental damage. The latter is caused, for instance, from artisanal fishing. We formulate a model of impulsive differential equations to describe the interplay between malaria dynamics, human intoxication, and ecosystem damage; affected by human awareness to these risks and levels of net usage. Our results show that an increase in mosquito net coverage reduces malaria prevalence and increases human intoxications. In addition, a high net coverage significantly reduces the risk perception to disease, naturally increases the awareness for intoxications from net handling, and scarcely increases the risk perception to collateral damage from net fishing. According to our model, campaigns aiming at reducing disease prevalence or intoxications are much more successful than those creating awareness to ecosystem damage. Furthermore, we can observe from our results that introducing closed fishing periods reduces environmental damage more significantly than strategies directed towards increasing the risk perception for net fishing.

LLIN Evaluation in Uganda Project (LLINEUP2)-Factors associated with coverage and use of long‑lasting insecticidal nets following the 2020-21 national mass distribution campaign: a cross-sectional survey of 12 districts

BACKGROUND

In 2020-2021, long-lasting insecticidal nets (LLINs) were distributed nationwide in Uganda during the COVID-19 pandemic. A cross-sectional survey was conducted in 12 districts to evaluate the impact of the campaign 1-5 months after LLIN distribution.

METHODS

During April-May 2021, households were randomly selected from target areas (1-7 villages) surrounding 12 government-run health facilities established as Malaria Reference Centres; at least 50 households were enrolled per cluster. Outcomes included household ownership of LLINs distributed through the universal coverage campaign (UCC) (at least one UCC LLIN), adequate coverage of UCC LLINs (at least one UCC LLIN per 2 residents), and use of LLINs (resident slept under a LLIN the previous night). Multivariate logistic regression models were used to identify household- and individual-level factors associated with outcomes, controlling for clustering around health facilities.

RESULTS

In total, 634 households, with 3342 residents and 1631 bed-nets, were included. Most households (93.4%) owned at least 1 UCC LLIN, but only 56.8% were adequately covered by UCC LLINs. In an adjusted analysis, the factor most strongly associated with adequate coverage by UCC LLINs was fewer household residents (1-4 vs 7-14; adjusted odds ratio [aOR] 12.96, 95% CI 4.76-35.26, p < 0.001; 5-6 vs 7-14 residents; aOR 2.99, 95% CI 1.21-7.42, p = 0.018). Of the 3166 residents of households that owned at least one UCC LLIN, only 1684 (53.2%) lived in adequately covered households; 89.9% of these used an LLIN the previous night, compared to 1034 (69.8%) of 1482 residents living in inadequately covered households. In an adjusted analysis, restricted to residents of inadequately covered households, LLIN use was higher in children under-five than those aged 5-15 years (aOR 3.04, 95% CI 2.08-4.46, p < 0.001), and higher in household heads than distantly-related residents (aOR 3.94, 95% CI 2.38-6.51, p < 0.001).

CONCLUSIONS

Uganda's 2021-21 campaign was successful, despite the COVID-19 pandemic. In future campaigns, strategies should be adopted to ensure high LLIN coverage, particularly for larger households. A better understanding of the drivers of LLIN use within households is needed to guide future interventions, educational messages, and behaviour change communication strategies; school-aged children and distantly-related residents appear vulnerable and could be targeted.