Laura Bloomfield

All Publications

• A multiplexed RT-LAMP assay for detection of group M HIV-1 in plasma or whole blood JOURNAL OF VIROLOGICAL METHODS Curtis, K. A., Morrison, D., Rudolph, D. L., Shankar, A., Bloomfield, L. P., Switzer, W. M., Owen, S. 2018; 255: 91–97

  Abstract

  Isothermal nucleic acid amplification techniques, such as reverse-transcription loop-mediated isothermal amplification (RT-LAMP), exhibit characteristics that are suitable for the development of a rapid, low-cost NAT that can be used at the POC. For demonstration of utility for global use, studies are needed to validate the performance of RT-LAMP for the detection of divergent subtypes. In this study, we designed and evaluated multiplexed HIV-1 integrase RT-LAMP primers to detect subtypes within group M, along with an RNase P positive internal processing and amplification control. Using a panel of 26 viral isolates representing the major circulating subtypes, we demonstrated detection of all isolates of subtypes A1, C, D, F1, F2, G, CRF01_AE, CRF02_AG, and two unique recombinant forms (URFs). A whole blood panel created with one representative isolate of each subtype was successfully amplified with the group M HIV-1 integrase and RNase P internal control primers. The group M HIV-1 RT-LAMP assay was further evaluated on 61 plasma specimens obtained from persons from Cameroon and Uganda. The sequence-conserved group M HIV-1 RT-LAMP primers, coupled to a low-cost amplification device, may improve diagnosis of acute infection at the POC and provide timely confirmation of HIV status.

  View details for DOI 10.1016/j.jviromet.2018.02.012

  View details for Web of Science ID 000430028300015

  View details for PubMedID 29474813

• Pathogen spillover during land conversion ECOLOGY LETTERS Faust, C. L., McCallum, H. I., Bloomfield, L. P., Gottdenker, N. L., Gillespie, T. R., Torney, C. J., Dobson, A. P., Plowright, R. K. 2018; 21 (4): 471–83

  Abstract

  Pathogen spillover from wildlife to domestic animals and humans, and the reverse, has caused significant epidemics and pandemics worldwide. Although pathogen emergence has been linked to anthropogenic land conversion, a general framework to disentangle underlying processes is lacking. We develop a multi-host model for pathogen transmission between species inhabiting intact and converted habitat. Interspecies contacts and host populations vary with the proportion of land converted; enabling us to quantify infection risk across a changing landscape. In a range of scenarios, the highest spillover risk occurs at intermediate levels of habitat loss, whereas the largest, but rarest, epidemics occur at extremes of land conversion. This framework provides insights into the mechanisms driving disease emergence and spillover during land conversion. The finding that the risk of spillover is highest at intermediate levels of habitat loss provides important guidance for conservation and public health policy.

  View details for DOI 10.1111/ele.12904

  View details for Web of Science ID 000427007400001

  View details for PubMedID 29466832

• Null expectations for disease dynamics in shrinking habitat: dilution or amplification? PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES Faust, C. L., Dobson, A. P., Gottdenker, N., Bloomfield, L. S., McCallum, H. I., Gillespie, T. R., Diuk-Wasser, M., Plowright, R. K. 2017; 372 (1722)

  Abstract

  As biodiversity declines with anthropogenic land-use change, it is increasingly important to understand how changing biodiversity affects infectious disease risk. The dilution effect hypothesis, which points to decreases in biodiversity as critical to an increase in infection risk, has received considerable attention due to the allure of a win-win scenario for conservation and human well-being. Yet some empirical data suggest that the dilution effect is not a generalizable phenomenon. We explore the response of pathogen transmission dynamics to changes in biodiversity that are driven by habitat loss using an allometrically scaled multi-host model. With this model, we show that declining habitat, and thus declining biodiversity, can lead to either increasing or decreasing infectious-disease risk, measured as endemic prevalence. Whether larger habitats, and thus greater biodiversity, lead to a decrease (dilution effect) or increase (amplification effect) in infection prevalence depends upon the pathogen transmission mode and how host competence scales with body size. Dilution effects were detected for most frequency-transmitted pathogens and amplification effects were detected for density-dependent pathogens. Amplification effects were also observed over a particular range of habitat loss in frequency-dependent pathogens when we assumed that host competence was greatest in large-bodied species. By contrast, only amplification effects were observed for density-dependent pathogens; host competency only affected the magnitude of the effect. These models can be used to guide future empirical studies of biodiversity-disease relationships across gradients of habitat loss. The type of transmission, the relationship between host competence and community assembly, the identity of hosts contributing to transmission, and how transmission scales with area are essential factors to consider when elucidating the mechanisms driving disease risk in shrinking habitat.This article is part of the themed issue 'Conservation, biodiversity and infectious disease: scientific evidence and policy implications'.

  View details for DOI 10.1098/rstb.2016.0173

  View details for Web of Science ID 000399956400013

  View details for PubMedID 28438921

• Contact structure, mobility, environmental impact and behaviour: the importance of social forces to infectious disease dynamics and disease ecology PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES Arthur, R. F., Gurley, E. S., Salje, H., Bloomfield, L. S., Jones, J. H. 2017; 372 (1719)

  Abstract

  Human factors, including contact structure, movement, impact on the environment and patterns of behaviour, can have significant influence on the emergence of novel infectious diseases and the transmission and amplification of established ones. As anthropogenic climate change alters natural systems and global economic forces drive land-use and land-cover change, it becomes increasingly important to understand both the ecological and social factors that impact infectious disease outcomes for human populations. While the field of disease ecology explicitly studies the ecological aspects of infectious disease transmission, the effects of the social context on zoonotic pathogen spillover and subsequent human-to-human transmission are comparatively neglected in the literature. The social sciences encompass a variety of disciplines and frameworks for understanding infectious diseases; however, here we focus on four primary areas of social systems that quantitatively and qualitatively contribute to infectious diseases as social-ecological systems. These areas are social mixing and structure, space and mobility, geography and environmental impact, and behaviour and behaviour change. Incorporation of these social factors requires empirical studies for parametrization, phenomena characterization and integrated theoretical modelling of social-ecological interactions. The social-ecological system that dictates infectious disease dynamics is a complex system rich in interacting variables with dynamically significant heterogeneous properties. Future discussions about infectious disease spillover and transmission in human populations need to address the social context that affects particular disease systems by identifying and measuring qualitatively important drivers.This article is part of the themed issue 'Opening the black box: re-examining the ecology and evolution of parasite transmission'.

  View details for DOI 10.1098/rstb.2016.0454

  View details for Web of Science ID 000397800300016

  View details for PubMedID 28289265