33 research outputs found

    The ecology and epidemiology of malaria parasitism in wild chimpanzee reservoirs

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    Chimpanzees (Pan troglodytes) harbor rich assemblages of malaria parasites, including three species closely related to P. falciparum (sub-genus Laverania), the most malignant human malaria parasite. Here, we characterize the ecology and epidemiology of malaria infection in wild chimpanzee reservoirs. We used molecular assays to screen chimpanzee fecal samples, collected longitudinally and cross-sectionally from wild populations, for malaria parasite mitochondrial DNA. We found that chimpanzee malaria parasitism has an early age of onset and varies seasonally in prevalence. A subset of samples revealed Hepatocystis mitochondrial DNA, with phylogenetic analyses suggesting that Hepatocystis appears to cross species barriers more easily than Laverania. Longitudinal and cross-sectional sampling independently support the hypothesis that mean ambient temperature drives spatiotemporal variation in chimpanzee Laverania infection. Infection probability peaked at similar to 24.5 degrees C, consistent with the empirical transmission optimum of P. falciparum in humans. Forest cover was also positively correlated with spatial variation in Laverania prevalence, consistent with the observation that forest-dwelling Anophelines are the primary vectors. Extrapolating these relationships across equatorial Africa, we map spatiotemporal variation in the suitability of chimpanzee habitat for Laverania transmission, offering a hypothetical baseline indicator of human exposure risk

    The ecology and epidemiology of malaria parasitism in wild chimpanzee reservoirs

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    This work was supported by grants from the National Institutes of Health R01AI091595, R01AI120810, R01AI050529, and P30AI045008 (B.H.H.); R01HL139337 (M.T.D.), the National Geographic Society (E.J.S.), the International Primatological Society (E.J.S.), and the American Society of Primatologists (E.J.S.), as well as fellowships from Harvard University (E.J.S.) and the National Science Foundation (E.J.S.).Chimpanzees (Pan troglodytes) harbor rich assemblages of malaria parasites, including three species closely related to P. falciparum (sub-genus Laverania), the most malignant human malaria parasite. Here, we characterize the ecology and epidemiology of malaria infection in wild chimpanzee reservoirs. We used molecular assays to screen chimpanzee fecal samples, collected longitudinally and cross-sectionally from wild populations, for malaria parasite mitochondrial DNA. We found that chimpanzee malaria parasitism has an early age of onset and varies seasonally in prevalence. A subset of samples revealed Hepatocystis mitochondrial DNA, with phylogenetic analyses suggesting that Hepatocystis appears to cross species barriers more easily than Laverania. Longitudinal and cross-sectional sampling independently support the hypothesis that mean ambient temperature drives spatiotemporal variation in chimpanzee Laverania infection. Infection probability peaked at ~24.5 °C, consistent with the empirical transmission optimum of P. falciparum in humans. Forest cover was also positively correlated with spatial variation in Laverania prevalence, consistent with the observation that forest-dwelling Anophelines are the primary vectors. Extrapolating these relationships across equatorial Africa, we map spatiotemporal variation in the suitability of chimpanzee habitat for Laverania transmission, offering a hypothetical baseline indicator of human exposure risk.Publisher PDFPeer reviewe

    Leukocyte-associated immunoglobulin-like receptor-1 blockade in combination with programmed death-ligand 1 targeting therapy mediates increased tumour control in mice

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    Collagen expression and structure in the tumour microenvironment are associated with tumour development and therapy response. Leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1) is a widely expressed inhibitory collagen receptor. LAIR-2 is a soluble homologue of LAIR-1 that competes for collagen binding. Multiple studies in mice implicate blockade of LAIR-1:collagen interaction in cancer as a promising therapeutic strategy. Here, we investigated the role of LAIR-1 in anti-tumour responses. We show that although LAIR-1 inhibits activation, proliferation, and cytokine production of mouse T cells in vitro, tumour outgrowth in LAIR-1-deficient mice did not differ from wild type mice in several in vivo tumour models. Furthermore, treatment with NC410, a LAIR-2-Fc fusion protein, did not result in increased tumour clearance in tested immunocompetent mice, which contrasts with previous data in humanized mouse models. This discrepancy may be explained by our finding that NC410 blocks human LAIR-1:collagen interaction more effectively than mouse LAIR-1:collagen interaction. Despite the lack of therapeutic impact of NC410 monotherapy, mice treated with a combination of NC410 and anti-programmed death-ligand 1 did show reduced tumour burden and increased survival. Using LAIR-1-deficient mice, we showed that this effect seemed to be dependent on the presence of LAIR-1. Taken together, our data demonstrate that the absence of LAIR-1 signalling alone is not sufficient to control tumour growth in multiple immunocompetent mouse models. However, combined targeting of LAIR-1 and PD-L1 results in increased tumour control. Thus, additional targeting of the LAIR-1:collagen pathway with NC410 is a promising approach to treating tumours where conventional immunotherapy is ineffective

    Regional Action Plan for the Conservation of the Nigeria–Cameroon Chimpanzee (Pan troglodytes ellioti)

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    First paragraph: This document represents the consensus of views from forestry and wildlife conservation agencies in Nigeria and Cameroon, local and international nongovernmental conservation organizations, and university-based researchers who met at a series of workshops in Cameroon and Nigeria to formulate a set of actions that, if implemented, will increase the longterm survival prospects of the Nigeria-Cameroon chimpanzee, Pan troglodytes ellioti. The Nigeria-Cameroon chimpanzee is the most endangered of all currently recognized chimpanzee subspecies, with a total remaining population of between 3,500 and 9,000 living in forested habitat to the north of the Sanaga River in Cameroon, the eastern edge of Nigeria, and in forest fragments in the Niger Delta and southwestern Nigeri

    The time scale of recombination rate evolution in great apes

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    We present three linkage-disequilibrium (LD)-based recombination maps generated using whole-genome sequence data from 10 Nigerian chimpanzees, 13 bonobos, and 15 western gorillas, collected as part of the Great Ape Genome Project (Prado-Martinez J, et al. 2013. Great ape genetic diversity and population history. Nature 499:471-475). We also identified species-specific recombination hotspots in each group using a modified LDhot framework, which greatly improves statistical power to detect hotspots at varying strengths. We show that fewer hotspots are shared among chimpanzee subspecies than within human populations, further narrowing the time scale of complete hotspot turnover. Further, using species-specific PRDM9 sequences to predict potential binding sites (PBS), we show higher predicted PRDM9 binding in recombination hotspots as compared to matched cold spot regions in multiple great ape species, including at least one chimpanzee subspecies. We found that correlations between broad-scale recombination rates decline more rapidly than nucleotide divergence between species. We also compared the skew of recombination rates at centromeres and telomeres between species and show a skew from chromosome means extending as far as 10-15Mb from chromosome ends. Further, we examined broad-scale recombination rate changes near a translocation in gorillas and found minimal differences as compared to other great ape species perhaps because the coordinates relative to the chromosome ends were unaffected. Finally, on the basis of multiple linear regression analysis, we found that various correlates of recombination rate persist throughout the African great apes including repeats, diversity, and divergence. Our study is the first to analyze within- And between-species genome-wide recombination rate variation in several close relatives

    Consensus Recommendations for the Use of Automated Insulin Delivery (AID) Technologies in Clinical Practice

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    International audienceThe significant and growing global prevalence of diabetes continues to challenge people with diabetes (PwD), healthcare providers and payers. While maintaining near-normal glucose levels has been shown to prevent or delay the progression of the long-term complications of diabetes, a significant proportion of PwD are not attaining their glycemic goals. During the past six years, we have seen tremendous advances in automated insulin delivery (AID) technologies. Numerous randomized controlled trials and real-world studies have shown that the use of AID systems is safe and effective in helping PwD achieve their long-term glycemic goals while reducing hypoglycemia risk. Thus, AID systems have recently become an integral part of diabetes management. However, recommendations for using AID systems in clinical settings have been lacking. Such guided recommendations are critical for AID success and acceptance. All clinicians working with PwD need to become familiar with the available systems in order to eliminate disparities in diabetes quality of care. This report provides much-needed guidance for clinicians who are interested in utilizing AIDs and presents a comprehensive listing of the evidence payers should consider when determining eligibility criteria for AID insurance coverage

    The development of Theileria parva, the cause of East Coast fever in cattle in South Africa - Part 2

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    This report deals with the forms of Theileria parva found in the blood corpuscles and their further development within the transmitting agent.The journals have been scanned with a SupraScan 10000RGB scanner; 24-bit true colour, 400 dpi, saved in TIFF-format. Copies of the master images have been converted to black & white, 1-bitmap images and OCRed with ABBYY Fine Reader v.9 software. Adobe Acrobat v.9 was used for the merging and conversion to the final presentation PDF-format.The Equine Research Centre, Faculty of Veterinary Science, University of Pretoria gave financial support to this digitisation project

    The development of Theileria parva , the cause of East Coast fever of cattle in South Africa

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    The journals have been scanned with a SupraScan 10000RGB scanner; 24-bit true colour, 400 dpi, saved in TIFF-format. Copies of the master images have been converted to black & white, 1-bitmap images and OCRed with ABBYY Fine Reader v.9 software. Adobe Acrobat v.9 was used for the merging and conversion to the final presentation PDF-format.The Equine Research Centre, Faculty of Veterinary Science, University of Pretoria gave financial support to this digitisation project

    Deriving In-Use PHEV Fuel Economy Predictions from Standardized Test Cycle Results

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    Plug-in hybrid electric vehicles (PHEVs) have potential to reduce or eliminate the U.S. dependence on foreign oil. Quantifying the amount of petroleum each uses, however, is challenging. To estimate in-use fuel economy for conventional vehicles the Environmental Protection Agency (EPA) conducts chassis dynamometer tests on standard historic drive cycles and then adjusts the resulting “raw” fuel economy measurements downward. Various publications, such as the forthcoming update to the SAE J1711 recommended practice for PHEV fuel economy testing, address the challenges of applying standard test procedures to PHEVs. This paper explores the issue of how to apply an adjustment method to such “raw” PHEV dynamometer test results in order to more closely estimate the in-use fuel and electricity consumption characteristics of these vehicles. The paper discusses two possible adjustment methods, and evaluates one method by applying it to dynamometer data and comparing the result to in-use fleet data (on an aftermarket conversion PHEV). The paper will also present the methodologies used to collect the data needed for this comparison
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