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Hazel A, Arzika AM, Abdou A, Lebas E, Porco TC, Maliki R, Doan T, Lietman TM, Keenan JD, Blumberg S. Temporal Trends in Phenotypic Macrolide and Nonmacrolide Resistance for Streptococcus pneumoniae Nasopharyngeal Samples Up to 36 Months after Mass Azithromycin Administration in a Cluster-Randomized Trial in Niger. Am J Trop Med Hyg 2023; 109:1107-1112. [PMID: 37783458 PMCID: PMC10622462 DOI: 10.4269/ajtmh.23-0431] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 08/08/2023] [Indexed: 10/04/2023] Open
Abstract
Azithromycin mass drug administration decreases child mortality but also selects for antibiotic resistance. Herein, we evaluate macrolide resistance of nasopharyngeal Streptococcus pneumoniae after azithromycin MDA. In a cluster-randomized trial, children 1-59 months received azithromycin or placebo biannually. Fifteen villages from each arm were randomly selected for antimicrobial resistance testing, and 10-15 randomly selected swabs from enrolled children at each village were processed for S. pneumoniae isolation and resistance testing. The primary prespecified outcome was macrolide resistance fraction for azithromycin versus placebo villages at 36 months. Secondary non-prespecified outcomes were comparisons of azithromycin and placebo for: 1) macrolide resistance at 12, 24, and 36 months; 2) nonmacrolide resistance at 36 months; and 3) suspected-erm mutation. At 36 months, 423 swabs were obtained and 322 grew S. pneumoniae, (azithromycin: 146/202, placebo: 176/221). Mean resistance prevalence was non-significantly higher in treatment than placebo (mixed-effects model: 14.6% vs. 8.9%; OR = 2.0, 95% CI: 0.99-3.97). However, when all time points were evaluated, macrolide resistance prevalence was significantly higher in the azithromycin group (β = 0.102, 95% CI: 0.04-0.167). For all nonmacrolides, resistance prevalence at 36 months was not different between the two groups. Azithromycin and placebo were not different for suspected-erm mutation prevalence. Macrolide resistance was higher in the azithromycin group over all time points, but not at 36 months. Although this suggests resistance may not continue to increase after biannual MDA, more studies are needed to clarify when MDA can safely decrease mortality and morbidity in lower- and middle-income countries.
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Affiliation(s)
- Ashley Hazel
- F. I. Proctor Foundation, University of California, San Francisco, California
| | | | - Amza Abdou
- Programme Nationale de Santé Oculaire, Niamey, Niger
| | - Elodie Lebas
- F. I. Proctor Foundation, University of California, San Francisco, California
| | - Travis C. Porco
- F. I. Proctor Foundation, University of California, San Francisco, California
| | | | - Thuy Doan
- F. I. Proctor Foundation, University of California, San Francisco, California
| | - Thomas M. Lietman
- F. I. Proctor Foundation, University of California, San Francisco, California
| | - Jeremy D. Keenan
- F. I. Proctor Foundation, University of California, San Francisco, California
| | - Seth Blumberg
- F. I. Proctor Foundation, University of California, San Francisco, California
- School of Medicine, University of California, San Francisco, California
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Pando C, Hazel A, Tsang LY, Razafindrina K, Andriamiadanarivo A, Rabetombosoa RM, Ambinintsoa I, Sadananda G, Small PM, Knoblauch AM, Rakotosamimanana N, Grandjean Lapierre S. A social network analysis model approach to understand tuberculosis transmission in remote rural Madagascar. BMC Public Health 2023; 23:1511. [PMID: 37558982 PMCID: PMC10410943 DOI: 10.1186/s12889-023-16425-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 07/31/2023] [Indexed: 08/11/2023] Open
Abstract
BACKGROUND Quality surveillance data used to build tuberculosis (TB) transmission models are frequently unavailable and may overlook community intrinsic dynamics that impact TB transmission. Social network analysis (SNA) generates data on hyperlocal social-demographic structures that contribute to disease transmission. METHODS We collected social contact data in five villages and built SNA-informed village-specific stochastic TB transmission models in remote Madagascar. A name-generator approach was used to elicit individual contact networks. Recruitment included confirmed TB patients, followed by snowball sampling of named contacts. Egocentric network data were aggregated into village-level networks. Network- and individual-level characteristics determining contact formation and structure were identified by fitting an exponential random graph model (ERGM), which formed the basis of the contact structure and model dynamics. Models were calibrated and used to evaluate WHO-recommended interventions and community resiliency to foreign TB introduction. RESULTS Inter- and intra-village SNA showed variable degrees of interconnectivity, with transitivity (individual clustering) values of 0.16, 0.29, and 0.43. Active case finding and treatment yielded 67%-79% reduction in active TB disease prevalence and a 75% reduction in TB mortality in all village networks. Following hypothetical TB elimination and without specific interventions, networks A and B showed resilience to both active and latent TB reintroduction, while Network C, the village network with the highest transitivity, lacked resiliency to reintroduction and generated a TB prevalence of 2% and a TB mortality rate of 7.3% after introduction of one new contagious infection post hypothetical elimination. CONCLUSION In remote Madagascar, SNA-informed models suggest that WHO-recommended interventions reduce TB disease (active TB) prevalence and mortality while TB infection (latent TB) burden remains high. Communities' resiliency to TB introduction decreases as their interconnectivity increases. "Top down" population level TB models would most likely miss this difference between small communities. SNA bridges large-scale population-based and hyper focused community-level TB modeling.
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Affiliation(s)
- Christine Pando
- Stony Brook University, 101 Nicolls Road, Stony Brook, NY, 11794-8343, USA
| | - Ashley Hazel
- Francis I. Proctor Foundation, University of California, San Francisco, 490 Illinois Street, 2nd Floor, San Francisco, CA, 94110, USA
| | - Lai Yu Tsang
- Stony Brook University, 101 Nicolls Road, Stony Brook, NY, 11794-8343, USA
| | | | | | - Roger Mario Rabetombosoa
- Centre ValBio Research Station, BP 33 Ranomafana, Ifanadiana, Madagascar
- Institut Pasteur de Madagascar, 101, Ambohitrakely, Antananarivo, Madagascar
| | - Ideal Ambinintsoa
- Centre ValBio Research Station, BP 33 Ranomafana, Ifanadiana, Madagascar
| | - Gouri Sadananda
- Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, USA
| | - Peter M Small
- Stony Brook University, 101 Nicolls Road, Stony Brook, NY, 11794-8343, USA
| | - Astrid M Knoblauch
- Institut Pasteur de Madagascar, 101, Ambohitrakely, Antananarivo, Madagascar
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | | | - Simon Grandjean Lapierre
- Institut Pasteur de Madagascar, 101, Ambohitrakely, Antananarivo, Madagascar.
- Centre de Recherche du Centre Hospitalier de L, Université de Montréal, 900 Saint-Denis, Montréal, H2X 3H8, Canada.
- Université de Montréal, 2900 Edouard Montpetit, Montreal, H3T 1J4, Canada.
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Blake A, Hazel A, Jakurama J, Matundu J, Bharti N. Disparities in mobile phone ownership reflect inequities in access to healthcare. PLOS Digit Health 2023; 2:e0000270. [PMID: 37410708 DOI: 10.1371/journal.pdig.0000270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 05/05/2023] [Indexed: 07/08/2023]
Abstract
Human movement and population connectivity inform infectious disease management. Remote data, particularly mobile phone usage data, are frequently used to track mobility in outbreak response efforts without measuring representation in target populations. Using a detailed interview instrument, we measure population representation in phone ownership, mobility, and access to healthcare in a highly mobile population with low access to health care in Namibia, a middle-income country. We find that 1) phone ownership is both low and biased by gender, 2) phone ownership is correlated with differences in mobility and access to healthcare, and 3) reception is spatially unequal and scarce in non-urban areas. We demonstrate that mobile phone data do not represent the populations and locations that most need public health improvements. Finally, we show that relying on these data to inform public health decisions can be harmful with the potential to magnify health inequities rather than reducing them. To reduce health inequities, it is critical to integrate multiple data streams with measured, non-overlapping biases to ensure data representativeness for vulnerable populations.
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Affiliation(s)
- Alexandre Blake
- Biology Department, Center for Infectious Disease Dynamics, Penn State University, University Park, Pennsylvania, United States of America
| | - Ashley Hazel
- Francis I. Proctor Foundation, University of California, San Francisco, California, United States of America
| | | | | | - Nita Bharti
- Biology Department, Center for Infectious Disease Dynamics, Penn State University, University Park, Pennsylvania, United States of America
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Hazel A, Davidson MC, Rogers A, Barrie MB, Freeman A, Mbayoh M, Kamara M, Blumberg S, Lietman TM, Rutherford GW, Jones JH, Porco TC, Richardson ET, Kelly JD. Social Network Analysis of Ebola Virus Disease During the 2014 Outbreak in Sukudu, Sierra Leone. Open Forum Infect Dis 2022; 9:ofac593. [PMID: 36467298 PMCID: PMC9709704 DOI: 10.1093/ofid/ofac593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 11/01/2022] [Indexed: 08/02/2023] Open
Abstract
Background Transmission by unreported cases has been proposed as a reason for the 2013-2016 Ebola virus (EBOV) epidemic decline in West Africa, but studies that test this hypothesis are lacking. We examined a transmission chain within social networks in Sukudu village to assess spread and transmission burnout. Methods Network data were collected in 2 phases: (1) serological and contact information from Ebola cases (n = 48, including unreported); and (2) interviews (n = 148), including Ebola survivors (n = 13), to identify key social interactions. Social links to the transmission chain were used to calculate cumulative incidence proportion as the number of EBOV-infected people in the network divided by total network size. Results The sample included 148 participants and 1522 contacts, comprising 10 social networks: 3 had strong links (>50% of cases) to the transmission chain: household sharing (largely kinship), leisure time, and talking about important things (both largely non-kin). Overall cumulative incidence for these networks was 37 of 311 (12%). Unreported cases did not have higher network centrality than reported cases. Conclusions Although this study did not find evidence that explained epidemic decline in Sukudu, it excluded potential reasons (eg, unreported cases, herd immunity) and identified 3 social interactions in EBOV transmission.
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Affiliation(s)
- Ashley Hazel
- Francis I. Proctor Foundation, University of California, San Francisco, San Francisco, California, USA
| | - Michelle C Davidson
- School of Medicine, University of California, San Francisco, San Francisco, California, USA
| | - Abu Rogers
- School of Medicine, Stanford University, Stanford, California, USA
| | - M Bailor Barrie
- Institute for Global Health Sciences, University of California, San Francisco, California, USA
- Partners in Health, Freetown, Sierra Leone
| | | | | | | | - Seth Blumberg
- Francis I. Proctor Foundation, University of California, San Francisco, San Francisco, California, USA
| | - Thomas M Lietman
- Francis I. Proctor Foundation, University of California, San Francisco, San Francisco, California, USA
| | - George W Rutherford
- Institute for Global Health Sciences, University of California, San Francisco, California, USA
- Department of Epidemiology and Biostatistics, University of California, San Francisco, California, USA
| | - James Holland Jones
- Division of Social Sciences, Doerr School of Sustainability and the Environment, Stanford University, Stanford, California, USA
| | - Travis C Porco
- Francis I. Proctor Foundation, University of California, San Francisco, San Francisco, California, USA
- Department of Epidemiology and Biostatistics, University of California, San Francisco, California, USA
| | - Eugene T Richardson
- Partners in Health, Freetown, Sierra Leone
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts, USA
- Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - J Daniel Kelly
- Francis I. Proctor Foundation, University of California, San Francisco, San Francisco, California, USA
- Institute for Global Health Sciences, University of California, San Francisco, California, USA
- Department of Epidemiology and Biostatistics, University of California, San Francisco, California, USA
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Hazel A, Meeks G, Bharti N, Jakurama J, Matundu J, Jones JH. Opportunities and constraints in women's resource security amid climate change: A case study of arid-living Namibian agro-pastoralists. Am J Hum Biol 2021; 33:e23633. [PMID: 34181282 DOI: 10.1002/ajhb.23633] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 06/03/2021] [Accepted: 06/04/2021] [Indexed: 11/06/2022] Open
Abstract
OBJECTIVE We describe the composition and variation of women's resource strategies in an arid-living Southern African agro-pastoralist society to gain insights into adaptation to climate-change-induced increased aridity. METHODS Using cross-sectional data from 210 women collected in 2009 across 28 agro-pastoralist villages in Kaokoveld Namibia, we conducted principal-component (PC) analysis of resource variables and constructed profiles of resource strategies from the major PCs. Next, we explored associations between key resource strategies and demographic measures and fitness proxies. RESULTS The first two PCs accounted for 43% of women's overall resource variation. PC1 reflects women's ability to access market resources via livestock trading, while PC2 captured women's direct food access. We found that market strategies were more common among married women and less common among women who have experienced child mortality. Women with higher subsistence security were more likely to be from the OvaHimba tribe and had a higher risk of gonorrhea exposure. We also qualitatively explored drought-induced pressure on women's livestock. Finally, we show that sexual networks were attenuated during drought, indicating strain on social support. CONCLUSIONS Our results highlight how agro-pastoralist women manage critical resources in unpredictable environments, and how resource strategies distribute among the women in our study. Goats as a commodity to obtain critical resources suggests that some women have flexibility during drought when gardens fail and cattle die. However, increased aridity and drought may eventually overwhelm husbandry practices in this region.
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Affiliation(s)
- Ashley Hazel
- Department of Earth System Science, Woods Institute for the Environment, Stanford University, Stanford, California, USA
| | - Gillian Meeks
- Department of Human Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA.,Program in Integrative Genetics and Genomics, University of California, Davis, Davis, California, USA
| | - Nita Bharti
- Department of Biology, The Center for Infectious Disease Dynamics, The Pennsylvania State University, State College, Pennsylvania, USA
| | | | | | - James Holland Jones
- Department of Earth System Science, Woods Institute for the Environment, Stanford University, Stanford, California, USA
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Jones JH, Pisor AC, Douglass KG, Bird RB, Ready E, Hazel A, Hackman J, Kramer KL, Kohler TA, Pontzer H, Towner MC. How can evolutionary and biological anthropologists engage broader audiences? Am J Hum Biol 2021; 33:e23592. [PMID: 33751710 DOI: 10.1002/ajhb.23592] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 02/25/2021] [Accepted: 02/26/2021] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVES With our diverse training, theoretical and empirical toolkits, and rich data, evolutionary and biological anthropologists (EBAs) have much to contribute to research and policy decisions about climate change and other pressing social issues. However, we remain largely absent from these critical, ongoing efforts. Here, we draw on the literature and our own experiences to make recommendations for how EBAs can engage broader audiences, including the communities with whom we collaborate, a more diverse population of students, researchers in other disciplines and the development sector, policymakers, and the general public. These recommendations include: (1) playing to our strength in longitudinal, place-based research, (2) collaborating more broadly, (3) engaging in greater public communication of science, (4) aligning our work with open-science practices to the extent possible, and (5) increasing diversity of our field and teams through intentional action, outreach, training, and mentorship. CONCLUSIONS We EBAs need to put ourselves out there: research and engagement are complementary, not opposed to each other. With the resources and workable examples we provide here, we hope to spur more EBAs to action.
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Affiliation(s)
- James Holland Jones
- Department of Earth System Science, Stanford University, Stanford, California, USA
| | - Anne C Pisor
- Department of Anthropology, Washington State University, Pullman, Washington, USA.,Department of Human Behavior, Ecology, and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Kristina G Douglass
- Department of Anthropology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Rebecca Bliege Bird
- Department of Anthropology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Elspeth Ready
- Department of Human Behavior, Ecology, and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Ashley Hazel
- Department of Earth System Science, Stanford University, Stanford, California, USA
| | - Joseph Hackman
- Department of Anthropology, University of Utah, Salt Lake City, Utah, USA
| | - Karen L Kramer
- Department of Anthropology, University of Utah, Salt Lake City, Utah, USA
| | - Timothy A Kohler
- Department of Anthropology, Washington State University, Pullman, Washington, USA.,Santa Fe Institute, Santa Fe, New Mexico, USA.,Crow Canyon Archaeological Center, Cortez, Colorado, USA
| | - Herman Pontzer
- Department of Evolutionary Anthropology, Duke University, Durham, North Carolina, USA
| | - Mary C Towner
- Department of Integrative Biology, Oklahoma State University, Stillwater, Oklahoma, USA
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7
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Jones JH, Hazel A, Almquist Z. Transmission-dynamics models for the SARS Coronavirus-2. Am J Hum Biol 2020; 32:e23512. [PMID: 32978876 PMCID: PMC7536961 DOI: 10.1002/ajhb.23512] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/02/2020] [Accepted: 08/03/2020] [Indexed: 12/22/2022] Open
Affiliation(s)
| | - Ashley Hazel
- Department of Earth System ScienceStanford UniversityStanfordCaliforniaUSA
| | - Zack Almquist
- Department of SociologyUniversity of WashingtonSeattleWashingtonUSA
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8
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Abstract
Social support networks play a key role in human livelihood security, especially in vulnerable communities. Here we explore how evolutionary ideas of kin selection and intrahousehold resource competition can explain individual variation in daily support network size and composition in a south-central Ethiopian agricultural community. We consider both domestic and agricultural help across two generations with different wealth-transfer norms that yield different contexts for sibling competition. For farmers who inherited land rights from family, firstborns were more likely to report daily support from parents and to have larger nonparental kin networks (n = 180). Compared with other farmers, firstborns were also more likely to reciprocate their parents' support, and to help nonparental kin without reciprocity. For farmers who received land rights from the government (n = 151), middle-born farmers reported more nonparental kin in their support networks compared with other farmers; nonreciprocal interactions were particularly common in both directions. This suggests a diversification of adult support networks to nonparental kin, possibly in response to a long-term parental investment disadvantage of being middle-born sons. In all instances, regardless of inheritance, lastborn farmers were the most disadvantaged in terms of kin support. Overall, we found that nonreciprocal interactions among farmers followed kin selection predictions. Direct reciprocity explained a substantial part of the support received from kin, suggesting the importance of the combined effects of kin selection and reciprocity for investment from kin.
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Affiliation(s)
- Lucie Clech
- Department of Anthropology and Archaeology, University of Bristol, 43 Woodland Rd, Bristol, BS81TH, UK. .,Department of Anthropology, Stanford University, 50, 450 Serra Mall, Stanford, CA, 94305, USA.
| | - Ashley Hazel
- Department of Earth System Science, Stanford University, 473 Via Ortega, Stanford, CA, 94305, USA
| | - Mhairi A Gibson
- Department of Anthropology and Archaeology, University of Bristol, 43 Woodland Rd, Bristol, BS81TH, UK
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Landig CS, Hazel A, Kellman BP, Fong JJ, Schwarz F, Agarwal S, Varki N, Massari P, Lewis NE, Ram S, Varki A. Evolution of the exclusively human pathogen Neisseria gonorrhoeae: Human-specific engagement of immunoregulatory Siglecs. Evol Appl 2019; 12:337-349. [PMID: 30697344 PMCID: PMC6346652 DOI: 10.1111/eva.12744] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Accepted: 11/14/2018] [Indexed: 12/18/2022] Open
Abstract
Neisseria gonorrhoeae causes the sexually transmitted disease gonorrhea exclusively in humans and uses multiple strategies to infect, including acquisition of host sialic acids that cap and mask lipooligosaccharide termini, while restricting complement activation. We hypothesized that gonococci selectively target human anti-inflammatory sialic acid-recognizing Siglec receptors on innate immune cells to blunt host responses and that pro-inflammatory Siglecs and SIGLEC pseudogene polymorphisms represent host evolutionary adaptations to counteract this interaction. N. gonorrhoeae can indeed engage multiple human but not chimpanzee CD33rSiglecs expressed on innate immune cells and in the genitourinary tract--including Siglec-11 (inhibitory) and Siglec-16 (activating), which we detected for the first time on human cervical epithelium. Surprisingly, in addition to LOS sialic acid, we found that gonococcal porin (PorB) mediated binding to multiple Siglecs. PorB also bound preferentially to human Siglecs and not chimpanzee orthologs, modulating host immune reactions in a human-specific manner. Lastly, we studied the distribution of null SIGLEC polymorphisms in a Namibian cohort with a high prevalence of gonorrhea and found that uninfected women preferentially harbor functional SIGLEC16 alleles encoding an activating immune receptor. These results contribute to the understanding of the human specificity of N. gonorrhoeae and how it evolved to evade the human immune defense.
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Affiliation(s)
- Corinna S. Landig
- Glycobiology Research and Training CenterUniversity of California, San DiegoLa JollaCalifornia
- Department of Cellular and Molecular MedicineUniversity of California, San DiegoLa JollaCalifornia
- Department of MedicineUniversity of California, San DiegoLa JollaCalifornia
| | - Ashley Hazel
- Department of Earth System ScienceStanford UniversityStanfordCalifornia
| | - Benjamin P. Kellman
- Department of PediatricsUniversity of California, San DiegoLa JollaCalifornia
- Bioinformatics and Systems Biology Graduate ProgramUniversity of California, San DiegoLa JollaCalifornia
| | - Jerry J. Fong
- Glycobiology Research and Training CenterUniversity of California, San DiegoLa JollaCalifornia
- Department of Cellular and Molecular MedicineUniversity of California, San DiegoLa JollaCalifornia
- Department of MedicineUniversity of California, San DiegoLa JollaCalifornia
| | - Flavio Schwarz
- Glycobiology Research and Training CenterUniversity of California, San DiegoLa JollaCalifornia
- Department of Cellular and Molecular MedicineUniversity of California, San DiegoLa JollaCalifornia
- Department of MedicineUniversity of California, San DiegoLa JollaCalifornia
| | - Sarika Agarwal
- Department of MedicineUniversity of Massachusetts Medical SchoolWorcesterMassachusetts
| | - Nissi Varki
- Glycobiology Research and Training CenterUniversity of California, San DiegoLa JollaCalifornia
- Department of PathologyUniversity of California, San DiegoLa JollaCalifornia
| | - Paola Massari
- Department of ImmunologyTufts University School of MedicineBostonMassachusetts
| | - Nathan E. Lewis
- Department of PediatricsUniversity of California, San DiegoLa JollaCalifornia
- Bioinformatics and Systems Biology Graduate ProgramUniversity of California, San DiegoLa JollaCalifornia
- Novo Nordisk Foundation Center for BiosustainabilityUniversity of California, San DiegoLa JollaCalifornia
| | - Sanjay Ram
- Department of MedicineUniversity of Massachusetts Medical SchoolWorcesterMassachusetts
| | - Ajit Varki
- Glycobiology Research and Training CenterUniversity of California, San DiegoLa JollaCalifornia
- Department of Cellular and Molecular MedicineUniversity of California, San DiegoLa JollaCalifornia
- Department of MedicineUniversity of California, San DiegoLa JollaCalifornia
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10
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Hazel A, Holland Jones J. Remoteness influences access to sexual partners and drives patterns of viral sexually transmitted infection prevalence among nomadic pastoralists. PLoS One 2018; 13:e0191168. [PMID: 29385170 PMCID: PMC5791958 DOI: 10.1371/journal.pone.0191168] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 12/05/2017] [Indexed: 01/01/2023] Open
Abstract
Sexually transmitted infections (STIs) comprise a significant portion of the infectious-disease burden among rural people in the Global South. Particular characteristics of ruralness-low-density settlements and poor infrastructure-make healthcare provision difficult, and remoteness, typically a characteristic of ruralness, often compounds the difficultly. Remoteness may also accelerate STI transmission, particularly that of viral STIs, through formation of small, highly connected sexual networks through which pathogens can spread rapidly, especially when partner concurrency is broadly accepted. Herein, we explored the effect of remoteness on herpes simplex virus type-2 (HSV-2) epidemiology among semi-nomadic pastoralists in northwestern (Kaokoveld) Namibia, where, in 2009 we collected HSV-2-specific antibody status, demographic, sexual network, and travel data from 446 subjects (women = 213, men = 233) in a cross-sectional study design. HSV-2 prevalence was high overall in Kaokoveld (>35%), but was heterogeneously distributed across locally defined residential regions: some regions had significantly higher HSV-2 prevalence (39-48%) than others (21-33%). Using log-linear models, we asked the following questions: 1) Are sexual contacts among people in high HSV-2-prevalence regions more likely to be homophilous (i.e., from the same region) than those among people from low-prevalence regions? 2) Are high-prevalence regions more "functionally" remote, in that people from those regions are more likely to travel within their own region than outside, compared to people from other regions? We found that high-prevalence regions were more sexually homophilous than low-prevalence regions and that those regions also had higher rates of within-region travel than the other regions. These findings indicate that remoteness can create contact structures for accelerated STI transmission among people who are already disproportionately vulnerable to consequences of untreated STIs.
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Affiliation(s)
- Ashley Hazel
- Department of Earth System Science, Stanford University, Stanford, California, United States of America
- Woods Institute for the Environment, Stanford University, Stanford, California, United States of America
- * E-mail:
| | - James Holland Jones
- Department of Earth System Science, Stanford University, Stanford, California, United States of America
- Woods Institute for the Environment, Stanford University, Stanford, California, United States of America
- Division of Biological Sciences, Imperial College London, London, United Kingdom
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Hazel A, Marino S, Simon C. An anthropologically based model of the impact of asymptomatic cases on the spread of Neisseria gonorrhoeae. J R Soc Interface 2016; 12:rsif.2015.0067. [PMID: 25808340 DOI: 10.1098/rsif.2015.0067] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Neisseria gonorrhoeae (GC) remains a serious burden in many high-sexual-activity, undertreated populations. Using empirical data from a 2009 study of GC burden among pastoralists in Kaokoveld, Namibia, we expand the standard gonorrhoea transmission model by using locally derived sexual contact data to explore transmission dynamics in a population with high rates of partner exchange and low treatment-seeking behaviour. We use the model to generate ball-park estimates for transmission probabilities and other parameter values for low-level (i.e. less than approx. 1200 copies/20 µl PCR reaction) asymptomatic infections, which account for 74% of all GC infections found in Kaokoveld in 2009, and to describe the impact of asymptomatic, low-level infections on overall prevalence patterns. Our results suggest that GC transmission probabilities are higher than previously estimated, that untreated infections take longer to clear than previously estimated and that a high prevalence of low-level infections is partially due to larger numbers of untreated, asymptomatic infections. These results provide new insights into the natural history of GC and the challenge of syndromic management programmes for the eradication of endemic gonorrhoea.
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Affiliation(s)
- Ashley Hazel
- School of Natural Resources and Environment, University of Michigan, Dana Building, 440 Church Street, Ann Arbor, MI 48109, USA Department of Anthropology, Stanford University, 450 Serra Mall, Building 50, Stanford, CA 94305, USA
| | - Simeone Marino
- School of Medicine, Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109-0620, USA
| | - Carl Simon
- Department of Mathematics, Ford School of Public Policy, Center for the Study of Complex Systems, University of Michigan, Weill Hall, 735 South State Street no. 4203, Ann Arbor, MI 48109, USA
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Abstract
BACKGROUND Although herpes simplex virus type 2 (HSV-2) epidemiology has been described for many western and/or urban populations, disease burden has not been characterized for remote, non-western, under treated populations, where patterns of risk and vulnerability may be very different. AIMS To understand demographic, behavioural and geographic influences on risk for HSV-2 in a population of mobile, rural pastoralists in northwestern Namibia. SUBJECTS AND METHODS The authors conducted a cross-sectional survey of reproductively aged adults (n = 445) across 28 villages in Kaokoveld, Namibia. All participants completed a questionnaire of demographic data, ecological interactions and sexual behaviour, and a rapid test specific for HSV-2. RESULTS HSV-2 status was significantly associated with being female (OR = 3.1, 95% CI = 2.00, 4.71), increasing age (men: OR = 7.5, 95% CI = 2.67, 20.85; women: OR = 6.2, 95% CI = 2.48, 15.50) and with higher wealth among men (OR = 5.1, 95% CI = 1.98, 13.09). CONCLUSIONS Higher risk among women can be explained, in part, by local hygiene practices and a preference for "dry" sex. There was considerable variation in prevalence by region, which appears to be linked to geographic remoteness. Culturally contextualized epidemiologic studies of remote, vulnerable populations can provide essential information for limiting the introduction and spread of new infections.
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Affiliation(s)
- Ashley Hazel
- a School of Natural Resources and Environment, University of Michigan , Ann Arbor , MI , USA .,b Department of Anthropology , Stanford University , Stanford , CA , USA , and
| | - Betsy Foxman
- c School of Public Health, Department of Epidemiology, University of Michigan , Ann Arbor , MI , USA
| | - Bobbi S Low
- a School of Natural Resources and Environment, University of Michigan , Ann Arbor , MI , USA
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Hazel A, Foxman B, Low B. P1-S1.22 HSV-2 prevalence across a pastoral landscape: transmission and transition among the Himba and Tjimba populations. Br J Vener Dis 2011. [DOI: 10.1136/sextrans-2011-050108.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Roy K, Borrill Z, Hazel A, Vestbo J, Singh D. Multiple flow rate modelling of nitric oxide in COPD - methodological concerns. Eur Respir Rev 2006. [DOI: 10.1183/09059180.00010129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Hazel A, Heil M. The influence of gravity in a two-dimensional model of airway reopening. J Biomech 2006. [DOI: 10.1016/s0021-9290(06)84019-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Thompson S, Hazel A, Bailey N, Bayliss J, Lee J. Identifying potential breeding sites for the stone curlew (Burhinus oedicnemus) in the UK. J Nat Conserv 2004. [DOI: 10.1016/j.jnc.2004.07.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Abstract
Previous work has demonstrated that, in single, paced left ventricular (LV) myocytes isolated from rats with hypertension, the extent of myocyte shortening and the amplitude of the cytosolic Ca2+ concentration transient are decreased relative to normal myocytes. These findings suggest that reduced sarcoplasmic reticular (SR) Ca2+ release could be responsible for hypertension-induced attenuation of the myocyte contractile response. Hypertension-induced reductions in SR Ca2+ release could be due to 1) a decrease in releasable SR Ca2+ content relative to the sarcoplasmic volume into which it is released or 2) alterations in the SR Ca2+ release mechanism such that the fractional release of SR Ca2+ is reduced. Using rapid cooling contractures (RCCs) to provide an index of SR Ca2+ content, we conducted a series of experiments designed to test the former hypothesis. Single LV myocytes were isolated from normotensive control rats and from rats with hypertension, which was induced by abdominal aortic banding (for approximately 4 mo). The extent of myocyte shortening during an RCC is taken to be directly proportional to SR Ca2+ content. As expected, the amplitudes of both twitches and RCCs decreased as pacing frequency increased from 0.2 to 1.0 Hz across both control and hypertensive groups, although the effect was greatest in control myocytes. A significant finding of this study was that, at both pacing frequencies, RCC magnitude was attenuated in hypertensive relative to control myocytes. These results suggest that in hypertension cellular Ca2+ homeostasis is altered and there is a mismatch between releasable SR Ca2+ content and the sarcoplasmic volume into which it is released.
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Affiliation(s)
- B L Stauffer
- Department of Kinesiology, University of Colorado, Boulder 80309-0354, USA
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