Dataset Information

Estimating individual exposure to malaria using local prevalence of malaria infection in the field.

ABSTRACT:

Background

Heterogeneity in malaria exposure complicates survival analyses of vaccine efficacy trials and confounds the association between immune correlates of protection and malaria infection in longitudinal studies. Analysis may be facilitated by taking into account the variability in individual exposure levels, but it is unclear how exposure can be estimated at an individual level.

Method and findings

We studied three cohorts (Chonyi, Junju and Ngerenya) in Kilifi District, Kenya to assess measures of malaria exposure. Prospective data were available on malaria episodes, geospatial coordinates, proximity to infected and uninfected individuals and residence in predefined malaria hotspots for 2,425 individuals. Antibody levels to the malaria antigens AMA1 and MSP1(142) were available for 291 children from Junju. We calculated distance-weighted local prevalence of malaria infection within 1 km radius as a marker of individual's malaria exposure. We used multivariable modified Poisson regression model to assess the discriminatory power of these markers for malaria infection (i.e. asymptomatic parasitaemia or clinical malaria). The area under the receiver operating characteristic (ROC) curve was used to assess the discriminatory power of the models. Local malaria prevalence within 1 km radius and AMA1 and MSP1(142) antibodies levels were independently associated with malaria infection. Weighted local malaria prevalence had an area under ROC curve of 0.72 (95%CI: 0.66-0.73), 0.71 (95%CI: 0.69-0.73) and 0.82 (95%CI: 0.80-0.83) among cohorts in Chonyi, Junju and Ngerenya respectively. In a small subset of children from Junju, a model incorporating weighted local malaria prevalence with AMA1 and MSP1(142) antibody levels provided an AUC of 0.83 (95%CI: 0.79-0.88).

Conclusion

We have proposed an approach to estimating the intensity of an individual's malaria exposure in the field. The weighted local malaria prevalence can be used as individual marker of malaria exposure in malaria vaccine trials and longitudinal studies of natural immunity to malaria.

SUBMITTER: Olotu A

PROVIDER: S-EPMC3315550 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Publications

Estimating individual exposure to malaria using local prevalence of malaria infection in the field.

Olotu Ally A Fegan Gregory G Wambua Juliana J Nyangweso George G Ogada Edna E Drakeley Chris C Marsh Kevin K Bejon Philip P

PloS one 20120329 3

<h4>Background</h4>Heterogeneity in malaria exposure complicates survival analyses of vaccine efficacy trials and confounds the association between immune correlates of protection and malaria infection in longitudinal studies. Analysis may be facilitated by taking into account the variability in individual exposure levels, but it is unclear how exposure can be estimated at an individual level.<h4>Method and findings</h4>We studied three cohorts (Chonyi, Junju and Ngerenya) in Kilifi District, Ke ...[more]

PMID: 22479349

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Project description:Prevalence of disease in wildlife populations, which is necessary for developing disease models and conducting epidemiologic analyses, is often understudied. Laboratory tests used to screen for diseases in wildlife populations often are validated only for domestic animals. Consequently, the use of these tests for wildlife populations may lead to inaccurate estimates of disease prevalence. We demonstrate the use of Bayesian latent class analysis (LCA) in determining the specificity and sensitivity of a competitive enzyme-linked immunosorbent assay (cELISA; VMRD (®), Inc.) serologic test used to identify exposure to Neospora caninum (hereafter N. caninum) in three wildlife populations in southeastern Ohio, USA. True prevalence of N. caninum exposure in these populations was estimated to range from 0.1% to 3.1% in American bison (Bison bison), 51.0% to 53.8% in Père David's deer (Elaphurus davidianus), and 40.0% to 45.9% in white-tailed deer (Odocoileus virginianus). The accuracy of the cELISA in American bison and Père David's deer was estimated to be close to the 96% sensitivity and 99% specificity reported by the manufacturer. Sensitivity in white-tailed deer, however, ranged from 78.9% to 99.9%. Apparent prevalence of N. caninum from the test results is not equal to the true prevalence in white-tailed deer and Père David's deer populations. Even when these species inhabit the same community, the true prevalence in the two deer populations differed from the true prevalence in the American bison population. Variances in prevalence for some species suggest differences in the epidemiology of N. caninum for these colocated populations. Bayesian LCA methods could be used as in this example to overcome some of the constraints on validating tests in wildlife species. The ability to accurately evaluate disease status and prevalence in a population improves our understanding of the epidemiology of multihost pathogen systems at the community level.

Project description:BackgroundUnderstanding the risks associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission during oral health care delivery and assessing mitigation strategies for dental offices are critical to improving patient safety and access to oral health care.MethodsThe authors invited licensed US dentists practicing primarily in private practice or public health to participate in a web-based survey in June 2020. Dentists from every US state (n = 2,195) answered questions about COVID-19-associated symptoms, SARS-CoV-2 infection, mental and physical health conditions, and infection control procedures used in their primary dental practices.ResultsMost of the dentists (82.2%) were asymptomatic for 1 month before administration of the survey; 16.6% reported being tested for SARS-CoV-2; and 3.7%, 2.7%, and 0% tested positive via respiratory, blood, and salivary samples, respectively. Among those not tested, 0.3% received a probable COVID-19 diagnosis from a physician. In all, 20 of the 2,195 respondents had been infected with SARS-CoV-2; weighted according to age and location to approximate all US dentists, 0.9% (95% confidence interval, 0.5 to 1.5) had confirmed or probable COVID-19. Dentists reported symptoms of depression (8.6%) and anxiety (19.5%). Enhanced infection control procedures were implemented in 99.7% of dentists' primary practices, most commonly disinfection, COVID-19 screening, social distancing, and wearing face masks. Most practicing dentists (72.8%) used personal protective equipment according to interim guidance from the Centers for Disease Control and Prevention.ConclusionsCOVID-19 prevalence and testing positivity rates were low among practicing US dentists. This indicates that the current infection control recommendations may be sufficient to prevent infection in dental settings.Practical implicationsDentists have enhanced their infection control practices in response to COVID-19 and may benefit from greater availability of personal protective equipment. ClinicalTrials.gov: NCT04423770.

Dataset Information

Estimating individual exposure to malaria using local prevalence of malaria infection in the field.

Background

Method and findings

Conclusion

Publications

Estimating individual exposure to malaria using local prevalence of malaria infection in the field.

Similar Datasets

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