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1.
Nat Commun ; 15(1): 8285, 2024 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-39333562

RESUMO

Importation of malaria infections is a suspected driver of sustained malaria prevalence on areas of Bioko Island, Equatorial Guinea. Quantifying the impact of imported infections is difficult because of the dynamic nature of the disease and complexity of designing a randomized trial. We leverage a six-month travel moratorium in and out of Bioko Island during the initial COVID-19 pandemic response to evaluate the contribution of imported infections to malaria prevalence on Bioko Island. Using a difference in differences design and data from island wide household surveys conducted before (2019) and after (2020) the travel moratorium, we compare the change in prevalence between areas of low historical travel to those with high historical travel. Here, we report that in the absence of a travel moratorium, the prevalence of infection in high travel areas was expected to be 9% higher than observed, highlighting the importance of control measures that target imported infections.


Assuntos
COVID-19 , Malária Falciparum , Plasmodium falciparum , SARS-CoV-2 , Viagem , Humanos , Guiné Equatorial/epidemiologia , COVID-19/epidemiologia , COVID-19/transmissão , Prevalência , Malária Falciparum/epidemiologia , SARS-CoV-2/isolamento & purificação , Pandemias , Feminino , Masculino , Ilhas , Adulto , Betacoronavirus
2.
Int J Infect Dis ; 147: 107197, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39128600

RESUMO

OBJECTIVES: This study assesses exposure to malaria vector mosquitos that is nonpreventable through use of nets, the contribution of outdoor and indoor biting towards residual vector exposure, and the risk factors for being bitten and for being infected with malaria parasites on Bioko Island, Equatorial Guinea. METHODS: Human behavior and malaria infection data were collected from 13,735 randomly selected residents during cross-sectional surveys, concomitantly with entomological human landing catches, indoors and outdoors, in 20 locations on the Island. Self-reported time of going indoors, going to bed and whether using a net were analyzed to impute for each respondent the number of bites received outdoors and indoors during the night before the survey. RESULTS: On average, each person received 2.7 (95% CI: 2.6-2.8) bites per night outdoors, 8.5 (8.3 to 8.7) bites indoors if not using a net, and 4.7 (4.5 to 4.8) bites indoors if using a net. Malaria infection was associated with more bites, regardless of whether received indoors or outdoors. Older age, male gender, not using a net, rural location, and going indoors later increased the risk of being bitten. The proportion of bites not averted by using a net was estimated as 66% (61 to 71). CONCLUSIONS: A large proportion of biting, mostly indoors, may not be preventable by bednets. Tools targeting indoor biting should be prioritized in Bioko. Novel vector control tools are urgently needed to reduce overall exposure to mosquito bites.


Assuntos
Mordeduras e Picadas de Insetos , Malária , Controle de Mosquitos , Mosquitos Vetores , Humanos , Guiné Equatorial/epidemiologia , Mordeduras e Picadas de Insetos/prevenção & controle , Mordeduras e Picadas de Insetos/epidemiologia , Masculino , Feminino , Adulto , Animais , Malária/transmissão , Malária/prevenção & controle , Malária/epidemiologia , Estudos Transversais , Controle de Mosquitos/métodos , Adolescente , Pessoa de Meia-Idade , Adulto Jovem , Criança , Mosquitos Vetores/parasitologia , Pré-Escolar , Fatores de Risco , Lactente , Idoso
3.
Malar J ; 23(1): 244, 2024 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-39138464

RESUMO

BACKGROUND: Adherence to anti-malarial treatment regimens is an important aspect of understanding and improving the impact of malaria case management. However, both adherence to artemisinin-based combination therapy (ACT) and the factors driving it vary widely. While many other evaluation activities have been conducted on Bioko Island, until now adherence to anti-malarial treatments, and in particular ACT has not been evaluated. METHODS: The implementation of a malaria indicator survey (MIS) conducted on Bioko in 2023 was leveraged to evaluate adherence to ACT provided to individuals testing positive following the survey. A follow-up team visited the targeted households, physically observed treatment blisters where possible, and provided messaging to household members on the importance of adhering to the treatment guidelines to household members. The team used survey data from the targeted households to make messaging as relevant to the household's particular context as possible. RESULTS: Overall ACT adherence on Bioko Island was low, around 50%, and this varied demographically and geographically. Some of the highest transmission areas had exceptionally low adherence, but no systematic relationship between proper adherence and Plasmodium falciparum prevalence was detected. Estimates of adherence from follow-up visits were much lower than survey-based estimates in the same households (52.5% versus 87.1%), suggesting that lack of proper adherence may be a much larger issue on Bioko Island than previously thought. CONCLUSION: Representative surveys can be easily adapted to provide empirical estimates of adherence to anti-malarial treatments, complementary to survey-based and health facility-based estimates. The large discrepancy between adherence as measured in this study and survey-based estimates on Bioko Island suggests a health facility-based study to quantify adherence among the population receiving treatment for symptomatic malaria may be necessary.


Assuntos
Antimaláricos , Adesão à Medicação , Projetos Piloto , Guiné Equatorial , Antimaláricos/uso terapêutico , Humanos , Feminino , Masculino , Adulto , Adesão à Medicação/estatística & dados numéricos , Pré-Escolar , Adolescente , Pessoa de Meia-Idade , Adulto Jovem , Criança , Malária Falciparum/tratamento farmacológico , Lactente , Artemisininas/uso terapêutico , Inquéritos e Questionários , Idoso , Ilhas
5.
Res Sq ; 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38645156

RESUMO

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.

6.
Malar J ; 22(1): 323, 2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37880774

RESUMO

BACKGROUND: Indoor residual spraying (IRS) is a common vector control strategy in countries with high malaria burden. Historically, social norms have prevented women from working in IRS programmes. The Bioko Island Malaria Elimination Project has actively sought to reduce gender inequality in malaria control operations for many years by promoting women's participation in IRS. METHODS: This study investigated the progress of female engagement and compared spray productivity by gender from 2010 to 2021, using inferential tests and multivariable regression. Spray productivity was measured by rooms sprayed by spray operator per day (RSOD), houses sprayed by spray operator per day (HSOD), and the daily productivity ratio (DPR), defined as the ratio of RSOD to HSOD, which standardized productivity by house size. RESULTS: The percentage of women participating in IRS has increased over time. The difference in DPR comparing male and female spray operators was only statistically significant (p < 0.05) for two rounds, where the value was higher for women compared to men. Regression analyses showed marginal, significant differences in DPR between men and women, but beta coefficients were extremely small and thus not indicative of a measurable effect of gender on operational performance. CONCLUSIONS: The quantitative analyses of spray productivity are counter to stigmatizing beliefs that women are less capable than male counterparts during IRS spray rounds. The findings from this research support the participation of women in IRS campaigns, and a renewed effort to implement equitable policies and practices that intentionally engage women in vector control activities.


Assuntos
Inseticidas , Malária , Humanos , Masculino , Feminino , Guiné Equatorial , Controle de Mosquitos , Malária/prevenção & controle
7.
PLOS Glob Public Health ; 3(9): e0001516, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37756280

RESUMO

Malaria surveillance is hampered by the widespread use of diagnostic tests with low sensitivity. Adequate molecular malaria diagnostics are often only available in centralized laboratories. PlasmoPod is a novel cartridge-based nucleic acid amplification test for rapid, sensitive, and quantitative detection of malaria parasites. PlasmoPod is based on reverse-transcription quantitative polymerase chain reaction (RT-qPCR) of the highly abundant Plasmodium spp. 18S ribosomal RNA/DNA biomarker and is run on a portable qPCR instrument which allows diagnosis in less than 30 minutes. Our analytical performance evaluation indicates that a limit-of-detection as low as 0.02 parasites/µL can be achieved and no cross-reactivity with other pathogens common in malaria endemic regions was observed. In a cohort of 102 asymptomatic individuals from Bioko Island with low malaria parasite densities, PlasmoPod accurately detected 83 cases, resulting in an overall detection rate of 81.4%. Notably, there was a strong correlation between the Cq values obtained from the reference RT-qPCR assay and those obtained from PlasmoPod. In an independent cohort, using dried blood spots from malaria symptomatic children living in the Central African Republic, we demonstrated that PlasmoPod outperforms malaria rapid diagnostic tests based on the PfHRP2 and panLDH antigens as well as thick blood smear microscopy. Our data suggest that this 30-minute sample-to-result RT-qPCR procedure is likely to achieve a diagnostic performance comparable to a standard laboratory-based RT-qPCR setup. We believe that the PlasmoPod rapid NAAT could enable widespread accessibility of high-quality and cost-effective molecular malaria surveillance data through decentralization of testing and surveillance activities, especially in elimination settings.

8.
Malar J ; 22(1): 72, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36859263

RESUMO

BACKGROUND: Since 2004, malaria transmission on Bioko Island has declined significantly as a result of the scaling-up of control interventions. The aim of eliminating malaria from the Island remains elusive, however, underscoring the need to adapt control to the local context. Understanding the factors driving the risk of malaria infection is critical to inform optimal suits of interventions in this adaptive approach. METHODS: This study used individual and household-level data from the 2015 and 2018 annual malaria indicator surveys on Bioko Island, as well as remotely-sensed environmental data in multilevel logistic regression models to quantify the odds of malaria infection. The analyses were stratified by urban and rural settings and by survey year. RESULTS: Malaria prevalence was higher in 10-14-year-old children and similar between female and male individuals. After adjusting for demographic factors and other covariates, many of the variables investigated showed no significant association with malaria infection. The factor most strongly associated was history of travel to mainland Equatorial Guinea (mEG), which increased the odds significantly both in urban and rural settings (people who travelled had 4 times the odds of infection). Sleeping under a long-lasting insecticidal net decreased significantly the odds of malaria across urban and rural settings and survey years (net users had around 30% less odds of infection), highlighting their contribution to malaria control on the Island. Improved housing conditions indicated some protection, though this was not consistent across settings and survey year. CONCLUSIONS: Malaria risk on Bioko Island is heterogeneous and determined by a combination of factors interacting with local mosquito ecology. These interactions grant further investigation in order to better adapt control according to need. The single most important risk factor identified was travel to mEG, in line with previous investigations, and represents a great challenge for the success of malaria control on the Island.


Assuntos
Culicidae , Malária , Criança , Animais , Humanos , Feminino , Masculino , Adolescente , Fatores de Risco , Ecologia , Guiné Equatorial
9.
Malar J ; 21(1): 328, 2022 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-36376966

RESUMO

BACKGROUND: In 2017, several new housing districts were constructed on Bioko Island, Equatorial Guinea. This case study assessed the impact construction projects had on mosquito larval habitats and the effectiveness of larval source management in reducing malaria vector density within the surrounding area. METHODS: Anopheline larval presence was assessed at 11 new construction sites by the proportion of larval habitats containing Anopheline pupae and late instar larval stages. Bacillus thuringiensis israelensis (Bti) larvicide was applied weekly to nine locations for 30 weeks, while two locations received no larvicide and acted as controls. Adult mosquito density was monitored via human landing collections in adjacent communities of six construction sites, including the two control sites. RESULTS: The sites that received Bti had significantly lower observation rates of both pupae (3.2% vs. 18.0%; p < 0.001) and late instar Anopheles spp. mosquitoes (14.1 vs. 43.6%; p < 0.001) compared to the two untreated sites. Anopheles spp. accounted for 67% of mosquitoes collected with human landing collections and were captured at significantly lower levels in communities adjacent to treated construction sites compared to untreated sites (p < 0.001), with an estimated 38% reduction in human biting rate (IRR: 0.62, 95% CI IRR: 0.55, 0.69). Seven months after the start of the study, untreated sites were treated due to ethical concerns given results from treatment sties, necessitating immediate Bti application. The following week, the number of habitats, the proportion of larval sites with Anopheles spp. pupae, late instars, and adult biting rates in adjacent communities to these sites all decreased to comparable levels across all sites. CONCLUSION: Findings suggest larval source management represents an effective intervention to suppress mosquito populations during infrastructure development. Incorporating larval source management into ongoing and planned construction initiatives represents an opportunity to fine tune vector control in response to anthropogenetic changes. Ideally, this should become standard practice in malaria-endemic regions in order to reduce viable mosquito habitats that are common by-products of construction.


Assuntos
Anopheles , Bacillus thuringiensis , Malária , Animais , Humanos , Anopheles/fisiologia , Malária/epidemiologia , Controle de Mosquitos/métodos , Larva , Reforma Urbana , Mosquitos Vetores , Pupa , Ecossistema
10.
PLoS Negl Trop Dis ; 16(1): e0009798, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35100277

RESUMO

BACKGROUND: Regular and comprehensive epidemiological surveys of the filarial nematodes Mansonella perstans and Loa loa in children, adolescents and adults living across Bioko Island, Equatorial Guinea are lacking. We aimed to demonstrate that blood retained on malaria rapid diagnostic tests, commonly deployed for malaria surveys, could be used as a source of nucleic acids for molecular based detection of M. perstans and L. loa. We wanted to determine the positivity rate and distribution of filarial nematodes across different age groups and geographical areas as well as to understand level of co-infections with malaria in an asymptomatic population. METHODOLOGY: M. perstans, L. loa and Plasmodium spp. parasites were monitored by qPCR in a cross-sectional study using DNA extracted from a subset malaria rapid diagnostic tests (mRDTs) collected during the annual malaria indicator survey conducted on Bioko Island in 2018. PRINCIPAL FINDINGS: We identified DNA specific for the two filarial nematodes investigated among 8.2% (263) of the 3214 RDTs screened. Positivity rates of M. perstans and L. loa were 6.6% and 1.5%, respectively. M. perstans infection were more prominent in male (10.5%) compared to female (3.9%) survey participants. M. perstans parasite density and positivity rate was higher among older people and the population living in rural areas. The socio-economic status of participants strongly influenced the infection rate with people belonging to the lowest socio-economic quintile more than 3 and 5 times more likely to be L. loa and M. perstans infected, respectively. No increased risk of being co-infected with Plasmodium spp. parasites was observed among the different age groups. CONCLUSIONS/SIGNIFICANCE: We found otherwise asymptomatic individuals were infected with M. perstans and L. loa. Our study demonstrates that employing mRDTs probed with blood for malaria testing represents a promising, future tool to preserve and ship NAs at room temperature to laboratories for molecular, high-throughput diagnosis and genotyping of blood-dwelling nematode filarial infections. Using this approach, asymptomatic populations can be reached and surveyed for infectious diseases beyond malaria.


Assuntos
Coinfecção/epidemiologia , Loa/isolamento & purificação , Malária/epidemiologia , Mansonella/isolamento & purificação , Adolescente , Adulto , Animais , Criança , Coinfecção/parasitologia , Estudos Transversais , DNA de Helmintos , Guiné Equatorial/epidemiologia , Feminino , Humanos , Loíase/sangue , Loíase/epidemiologia , Malária/sangue , Masculino , Mansonelose/sangue , Mansonelose/epidemiologia , Pessoa de Meia-Idade , Plasmodium/isolamento & purificação , Prevalência , Fatores Socioeconômicos
11.
Malar J ; 21(1): 23, 2022 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-35073934

RESUMO

BACKGROUND: Surveillance programmes often use malaria rapid diagnostic tests (RDTs) to determine the proportion of the population carrying parasites in their peripheral blood to assess the malaria transmission intensity. Despite an increasing number of reports on false-negative and false-positive RDT results, there is a lack of systematic quality control activities for RDTs deployed in malaria surveillance programmes. METHODS: The diagnostic performance of field-deployed RDTs used for malaria surveys was assessed by retrospective molecular analysis of the blood retained on the tests. RESULTS: Of the 2865 RDTs that were collected in 2018 on Bioko Island and analysed in this study, 4.7% had a false-negative result. These false-negative RDTs were associated with low parasite density infections. In 16.6% of analysed samples, masked pfhrp2 and pfhrp3 gene deletions were identified, in which at least one Plasmodium falciparum strain carried a gene deletion. Among all positive RDTs analysed, 28.4% were tested negative by qPCR and therefore considered to be false-positive. Analysing the questionnaire data collected from the participants, this high proportion of false-positive RDTs could be explained by P. falciparum histidine rich protein 2 (PfHRP2) antigen persistence after recent malaria treatment. CONCLUSION: Malaria surveillance depending solely on RDTs needs well-integrated quality control procedures to assess the extent and impact of reduced sensitivity and specificity of RDTs on malaria control programmes.


Assuntos
Antígenos de Protozoários/análise , Coinfecção/diagnóstico , Testes Diagnósticos de Rotina/estatística & dados numéricos , Malária/diagnóstico , Vigilância da População , Proteínas de Protozoários/análise , Coinfecção/epidemiologia , Guiné Equatorial/epidemiologia , Reações Falso-Positivas , Incidência , Malária/epidemiologia , Malária Falciparum/diagnóstico , Malária Falciparum/epidemiologia , Ácidos Nucleicos/análise , Plasmodium falciparum/isolamento & purificação , Plasmodium malariae/isolamento & purificação , Plasmodium ovale/isolamento & purificação , Estudos Retrospectivos
12.
PLOS Digit Health ; 1(5): e0000025, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-36812503

RESUMO

Public health interventions require evidence-based decision-making to maximize impact. Spatial decision support systems (SDSS) are designed to collect, store, process and analyze data to generate knowledge and inform decisions. This paper discusses how the use of a SDSS, the Campaign Information Management System (CIMS), to support malaria control operations on Bioko Island has impacted key process indicators of indoor residual spraying (IRS): coverage, operational efficiency and productivity. We used data from the last five annual IRS rounds (2017 to 2021) to estimate these indicators. IRS coverage was calculated as the percentage of houses sprayed per unit area, represented by 100x100 m map-sectors. Optimal coverage was defined as between 80% and 85%, and under and overspraying as coverage below 80% and above 85%, respectively. Operational efficiency was defined as the fraction of map-sectors that achieved optimal coverage. Daily productivity was expressed as the number of houses sprayed per sprayer per day (h/s/d). These indicators were compared across the five rounds. Overall IRS coverage (i.e. percent of total houses sprayed against the overall denominator by round) was highest in 2017 (80.2%), yet this round showed the largest proportion of oversprayed map-sectors (36.0%). Conversely, despite producing a lower overall coverage (77.5%), the 2021 round showed the highest operational efficiency (37.7%) and the lowest proportion of oversprayed map-sectors (18.7%). In 2021, higher operational efficiency was also accompanied by marginally higher productivity. Productivity ranged from 3.3 h/s/d in 2020 to 3.9 h/s/d in 2021 (median 3.6 h/s/d). Our findings showed that the novel approach to data collection and processing proposed by the CIMS has significantly improved the operational efficiency of IRS on Bioko. High spatial granularity during planning and deployment together with closer follow-up of field teams using real-time data supported more homogeneous delivery of optimal coverage while sustaining high productivity.

13.
PLoS One ; 16(9): e0248646, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34469444

RESUMO

BACKGROUND: Geospatial datasets of population are becoming more common in models used for health policy. Publicly-available maps of human population make a consistent picture from inconsistent census data, and the techniques they use to impute data makes each population map unique. Each mapping model explains its methods, but it can be difficult to know which map is appropriate for which policy work. High quality census datasets, where available, are a unique opportunity to characterize maps by comparing them with truth. METHODS: We use census data from a bed-net mass-distribution campaign on Bioko Island, Equatorial Guinea, conducted by the Bioko Island Malaria Elimination Program as a gold standard to evaluate LandScan (LS), WorldPop Constrained (WP-C) and WorldPop Unconstrained (WP-U), Gridded Population of the World (GPW), and the High-Resolution Settlement Layer (HRSL). Each layer is compared to the gold-standard using statistical measures to evaluate distribution, error, and bias. We investigated how map choice affects burden estimates from a malaria prevalence model. RESULTS: Specific population layers were able to match the gold-standard distribution at different population densities. LandScan was able to most accurately capture highly urban distribution, HRSL and WP-C matched best at all other lower population densities. GPW and WP-U performed poorly everywhere. Correctly capturing empty pixels is key, and smaller pixel sizes (100 m vs 1 km) improve this. Normalizing areas based on known district populations increased performance. The use of differing population layers in a malaria model showed a disparity in results around transition points between endemicity levels. DISCUSSION: The metrics in this paper, some of them novel in this context, characterize how these population maps differ from the gold standard census and from each other. We show that the metrics help understand the performance of a population map within a malaria model. The closest match to the census data would combine LandScan within urban areas and the HRSL for rural areas. Researchers should prefer particular maps if health calculations have a strong dependency on knowing where people are not, or if it is important to categorize variation in density within a city.


Assuntos
Malária/epidemiologia , Densidade Demográfica , Guiné Equatorial/epidemiologia , Humanos , Mapas como Assunto , Plasmodium falciparum , População Urbana/estatística & dados numéricos
15.
Malar J ; 19(1): 277, 2020 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-32746919

RESUMO

At the beginning of 2019, a sudden surge of malaria cases was observed in the district of Riaba, Bioko Island. Between January and April, confirmed malaria cases increased 3.8-fold compared to the same period in 2018. Concurrently, anopheline human biting rate (HBR) increased 2.1-fold. During the outbreak, 82.2% of the district population was tested for malaria with a rapid diagnostic test; 37.2% of those tested had a detectable infection and were treated according to national guidelines. Vector control interventions, including indoor residual spraying and larval source management were scaled-up. After the interventions, the number of confirmed cases decreased by 70% and the overall parasite prevalence in the communities by 43.8%. Observed prevalence in a follow up malaria indicator survey, however, was significantly higher than elsewhere on the island, and higher than in previous years. There was no significant reduction in HBR, which remained high for the rest of the year. The surge was attributed to various factors, chiefly increased rainfall and a large number of anthropogenic anopheline breeding sites created by construction works. This case study highlights the need for sustained vector control interventions and multi-sector participation, particularly in malaria control and elimination settings with persistently high local malaria receptivity.


Assuntos
Surtos de Doenças , Malária Falciparum/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Guiné Equatorial/epidemiologia , Feminino , Humanos , Lactente , Recém-Nascido , Malária Falciparum/prevenção & controle , Masculino , Pessoa de Meia-Idade , Plasmodium falciparum/fisiologia , Prevalência , Adulto Jovem
16.
Sci Rep ; 10(1): 12305, 2020 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-32703999

RESUMO

The use of malaria rapid diagnostic tests (RDTs) as a source for nucleic acids that can be analyzed via nucleic acid amplification techniques has several advantages, including minimal amounts of blood, sample collection, simplified storage and shipping conditions at room temperature. We have systematically developed and extensively evaluated a procedure to extract total nucleic acids from used malaria RDTs. The co-extraction of DNA and RNA molecules from small volumes of dried blood retained on the RDTs allows detection and quantification of P. falciparum parasites from asymptomatic patients with parasite densities as low as 1 Pf/µL blood using reverse transcription quantitative PCR. Based on the extraction protocol we have developed the ENAR (Extraction of Nucleic Acids from RDTs) approach; a complete workflow for large-scale molecular malaria surveillance. Using RDTs collected during a malaria indicator survey we demonstrated that ENAR provides a powerful tool to analyze nucleic acids from thousands of RDTs in a standardized and high-throughput manner. We found several, known and new, non-synonymous single nucleotide polymorphisms in the propeller region of the kelch 13 gene among isolates circulating on Bioko Island, Equatorial Guinea.


Assuntos
Malária Falciparum/diagnóstico , Malária Falciparum/epidemiologia , Técnicas de Diagnóstico Molecular/métodos , Ácidos Nucleicos/isolamento & purificação , Adulto , Animais , Coleta de Amostras Sanguíneas , DNA de Protozoário/sangue , DNA de Protozoário/genética , DNA de Protozoário/isolamento & purificação , Guiné Equatorial/epidemiologia , Feminino , Humanos , Ilhas , Malária Falciparum/parasitologia , Masculino , Parasitos/genética , Plasmodium falciparum/genética , Polimorfismo de Nucleotídeo Único/genética , Proteínas de Protozoários/genética , Inquéritos e Questionários , Adulto Jovem
17.
J Med Entomol ; 56(4): 1071-1077, 2019 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-30882148

RESUMO

Sustaining high levels of indoor residual spraying (IRS) coverage (≥85%) for community protection against malaria remains a challenge for IRS campaigns. We examined biting rates and insecticide resistance in Culex species and Anopheles gambiae s.l., and their potential effect on community adherence to IRS. The average IRS coverage in urban Malabo between 2015 and 2017 remained at 80%. Culex biting rate increased 6.0-fold (P < 0.001) between 2014 and 2017, reaching 8.08 bites per person per night, whereas that of An. gambiae s.l. remained steady at around 0.68. Although An. gambiae s.l. was susceptible to carbamates and organophosphates insecticides, Culex spp. were phenotypically resistant to all four main classes of WHO-recommended IRS insecticides. Similarly, the residual activity of the organophosphate insecticide used since 2017, ACTELLIC 300CS, was 8 mo for An. gambiae s.l., but was almost absent against Culex for 2 mo post-spray. A survey conducted in 2018 within urban Malabo indicated that 77.0% of respondents related IRS as means of protection against mosquito bites, but only 3.2% knew that only Anopheles mosquitoes transmit malaria. Therefore, the increasing biting rates of culicines in urban Malabo, and their resistance to all IRS insecticides, is raising concern that a growing number of people may refuse to participate in IRS as result of its perceived failure in controlling mosquitoes. Although this is not yet the case on Bioko Island, communication strategies need refining to sensitize communities about the effectiveness of IRS in controlling malaria vectors in the midst of insecticide resistance in nonmalaria vector mosquitoes.


Assuntos
Culex , Resistência a Inseticidas , Controle de Mosquitos , Animais , Cidades , Guiné Equatorial , Comportamento Alimentar , Malária/prevenção & controle , Malária/transmissão
18.
BMC Infect Dis ; 18(1): 298, 2018 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-29970017

RESUMO

BACKGROUND: The introduction of anti-retroviral treatment (ART) has significantly reduced mortality and morbidity associated with HIV/AIDS. While treatment at early stages of the disease is related to a better prognosis, late presentation (LP) to care is harmful to the infected person, the society and is more costly. We aimed to describe late presentation to HIV care, its associated factors and consequences in patients followed up in a tertiary hospital in Cameroon. METHODS: We retrospectively assessed patients' files between 1996 and 2014 at the Douala general hospital (DGH) HIV treatment centre. Late presentation (LP) to HIV care was defined as a CD4+ T cell count< 350 cells/mm3 or advanced clinical stages of the disease (WHO stages 3/4) at first presentation for care. We used logistic regression to study factors associated with late presentation and assessed occurrence of opportunistic infections and mortality at 3, 6 and 12 months after presentation to care. RESULTS: Of 1866 files studied, mean age was 40 (SD: 10) years, median CD4+ T cell count was 147 (IQR: 63-270) cells/mm3, 58.2% were at HIV clinical stages 3 and 4. The prevalence of late presentation to HIV care was 89.7% (95% CI: 88.2-91.0%) and remained above 80% from 1996 to 2014. Circumstances of diagnosis: prevention of mother to child transmission program/blood donation (OR = 0.16, 95% CI 0.10-0.29), having a positive partner (OR = 0.16, 95%CI = 0.10-0.26), and routine screening (OR = 0.13, 95%CI = 0.10-0.19) reduced the odds of presenting late compared to clinical suspicion. Students had lower odds of presenting late compared to people who had an employment (OR = 0.50, 95%CI = 0.26-0.98). Calendar time OR = 1.64, 95% CI = 1.08-2.48 for ≥2010 vs. < 2005) increased the odds of late presentation. Mortality and opportunistic infections prevalence remained significantly higher in late presenters at 3, 6 and 12 months than in early presenters. CONCLUSION: Late presentation to HIV care is very high at the DGH and is related to poor outcome. More screening and sensitization campaigns should be carried out in the population to diagnose the disease at an earlier stage.


Assuntos
Síndrome da Imunodeficiência Adquirida/terapia , Infecções por HIV/terapia , Tempo para o Tratamento , Adolescente , Adulto , Camarões , Diagnóstico Tardio , Feminino , Hospitais Gerais , Humanos , Transmissão Vertical de Doenças Infecciosas/prevenção & controle , Modelos Logísticos , Masculino , Prevalência , Estudos Retrospectivos , Fatores de Risco , Tempo para o Tratamento/estatística & dados numéricos , Resultado do Tratamento , Adulto Jovem
19.
J Viral Hepat ; 25(12): 1582-1587, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30047565

RESUMO

Hepatitis B virus (HBV) infection is hyperendemic in Cameroon, and healthcare workers (HCWs) are at high risk of infection. We aimed to assess prevalence, risk factors and vaccine coverage of HBV infection among HCWs in Cameroon. We conducted a cross-sectional study in 16 hospitals across all regions of Cameroon. HCWs were tested for HBV using rapid diagnostic tests (RDT). We collected data on socio-demographics and HBV vaccination status. We estimated prevalence of HBV and used Poisson regression models with robust standard errors to model the prevalence ratios of HBV positivity between covariates. We enrolled 1824 of 1836 eligible HCWs (97.5%). The mean age was 34 (SD: 10) years, 65.3% (n = 1787) were women, and 11.4% (n = 1747) had three or more doses of the HBV vaccine. Overall, we found a HBV prevalence of 8.7% (95% CI: 5.2%-14.3%). Patient transporters had the highest crude prevalence (14.3%; 95%CI: 5.4%-32.9%), whereas medical doctors had the lowest (3.2%; 95%CI: 0.8%-12.1%). The Far North Region had the highest prevalence of HBV (24.0%; 95%CI: 18.3%-30.8%). HBV prevalence decreased with increasing doses of the HBV vaccine (10.3% for no doses vs 3.5% for three or more doses; P < 0.001). In conclusion, approximately 1 in 12 HCWs in Cameroon have evidence of HBV infection, yet fewer than 1 in 6 have been fully vaccinated. Our results illustrate the urgent need to scale up systematic HBV screening and targeted vaccination of HCWs in the region.


Assuntos
Pessoal de Saúde , Vacinas contra Hepatite B/administração & dosagem , Hepatite B/epidemiologia , Hepatite B/prevenção & controle , Cobertura Vacinal/estatística & dados numéricos , Adulto , Camarões/epidemiologia , Estudos Transversais , Feminino , Vacinas contra Hepatite B/imunologia , Hospitais , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Inquéritos e Questionários , Adulto Jovem
20.
BMC Res Notes ; 10(1): 238, 2017 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-28673364

RESUMO

BACKGROUND: Malnutrition is common in acutely ill patients occurring in 30-50% of hospitalized patients. Awareness and screening for malnutrition is lacking in most health institutions in sub-Saharan Africa. This study aimed at screening for malnutrition using anthropometric and laboratory indices in patients admitted to the internal medicine wards. METHODS: A cross-sectional study. We screened for malnutrition in 251 consecutive patients admitted from January to March 2013 in the internal medicine wards. Malnutrition defined as body mass index (BMI) less than 18.5 kg/m2 and/or mid upper arm circumference (MUAC) less than 22 cm in women and 23 cm in men. Weight loss greater than 10% in the last 6 months prior to admission, relevant laboratory data, diagnosis at discharge and length of hospital stay (LOS) were also recorded. RESULTS: Mean age was 47 (SD 16) years. 52.6% were male. Mean BMI was 24.44 (SD 5.79) kg/m2 and MUAC was 27.8 (SD 5.0) cm. Median LOS was 7 (IQR 5-12) days. 42.4% of patients reported weight loss greater than 10% in the 6 months before hospitalization. MUAC and BMI correlated significantly (r = 0.78; p < 0.0001) and malnutrition by the two methods showed moderate agreement (κ = 0.56; p < 0.0001). Using the two methods in combination, the prevalence of malnutrition was 19.34% (35/251). Blood albumin and hemoglobin were significantly lower in malnourished patients. Malnourished patients had a significantly longer LOS (p = 0.019) when compared to those with no malnutrition. Malnutrition was most common amongst patients with malignancy. CONCLUSION: Malnutrition is common in patients admitted to the medical wards of the Douala General Hospital. Nutritional screening and assessment should be integrated in the care package of all admitted patients.


Assuntos
Doenças Cardiovasculares/diagnóstico , Infecções por HIV/diagnóstico , Desnutrição/diagnóstico , Estado Nutricional , Tuberculose Pulmonar/diagnóstico , Adulto , Idoso , Antropometria , Índice de Massa Corporal , Camarões , Doenças Cardiovasculares/complicações , Doenças Cardiovasculares/fisiopatologia , Estudos Transversais , Feminino , Infecções por HIV/complicações , Infecções por HIV/fisiopatologia , Hemoglobinas/metabolismo , Hospitais Gerais , Humanos , Tempo de Internação/estatística & dados numéricos , Masculino , Desnutrição/complicações , Desnutrição/fisiopatologia , Pessoa de Meia-Idade , Avaliação Nutricional , Albumina Sérica Humana/metabolismo , Tuberculose Pulmonar/complicações , Tuberculose Pulmonar/fisiopatologia , Redução de Peso
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