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Ismail S, Farner J, Couper L, Mordecai E, Lyberger K. Temperature and intraspecific variation affect host-parasite interactions. Oecologia 2024; 204:389-399. [PMID: 38006450 DOI: 10.1007/s00442-023-05481-z] [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: 01/17/2023] [Accepted: 11/06/2023] [Indexed: 11/27/2023]
Abstract
Parasites play key roles in regulating aquatic ecosystems, yet the impact of climate warming on their ecology and disease transmission remains poorly understood. Isolating the effect of warming is challenging as transmission involves multiple interacting species and potential intraspecific variation in temperature responses of one or more of these species. Here, we leverage a wide-ranging mosquito species and its facultative parasite as a model system to investigate the impact of temperature on host-parasite interactions and disease transmission. We conducted a common garden experiment measuring parasite growth and infection rates at seven temperatures using 12 field-collected parasite populations and a single mosquito population. We find that both free-living growth rates and infection rates varied with temperature, which were highest at 18-24.5 °C and 13 °C, respectively. Further, we find intraspecific variation in peak performance temperature reflecting patterns of local thermal adaptation-parasite populations from warmer source environments typically had higher thermal optima for free-living growth rates. For infection rates, we found a significant interaction between parasite population and nonlinear effects of temperature. These findings underscore the need to consider both host and parasite thermal responses, as well as intraspecific variation in thermal responses, when predicting the impacts of climate change on disease in aquatic ecosystems.
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Affiliation(s)
- Sherine Ismail
- Department of Biology, Stanford University, Stanford, USA
| | | | - Lisa Couper
- Department of Biology, Stanford University, Stanford, USA
| | - Erin Mordecai
- Department of Biology, Stanford University, Stanford, USA
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López-Rosero A, Sippy R, Stewart-Ibarra AM, Ryan SJ, Mordecai E, Heras F, Beltrán E, Costales JA, Neira M. High prevalence of Zika virus infection in populations of Aedes aegypti from South-western Ecuador. PLoS Negl Trop Dis 2024; 18:e0011908. [PMID: 38236943 PMCID: PMC10826935 DOI: 10.1371/journal.pntd.0011908] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 07/31/2023] [Revised: 01/30/2024] [Accepted: 01/08/2024] [Indexed: 01/31/2024] Open
Abstract
We performed an arboviral survey in mosquitoes from four endemic Ecuadorian cities (Huaquillas, Machala, Portovelo and Zaruma) during the epidemic period 2016-2018. Collections were performed during the pre-rainy season (2016), peak transmission season (2017) and post-rainy season (2018). Ae. aegypti mosquitoes were pooled by date, location and sex. Pools were screened by RT-PCR for the presence of ZIKV RNA, and infection rates (IRs) per 1,000 specimens were calculated. A total of 2,592 pools (comprising 6,197 mosquitoes) were screened. Our results reveal high IRs in all cities and periods sampled. Overall IRs among female mosquitoes were highest in Machala (89.2), followed by Portovelo (66.4), Zaruma (47.4) and Huaquillas (41.9). Among male mosquitoes, overall IRs were highest in Machala (35.6), followed by Portovelo (33.1), Huaquillas (31.9) and Zaruma (27.9), suggesting that alternative transmission routes (vertical/venereal) can play important roles for ZIKV maintenance in the vector population of these areas. Additionally, we propose that the stabilization of ZIKV vertical transmission in the vector population could help explain the presence of high IRs in field-caught mosquitoes during inter-epidemic periods.
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Affiliation(s)
- Andrea López-Rosero
- Centro de Investigación para la Salud en América Latina (CISeAL), Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Rachel Sippy
- Institute for Global Health and Translational Science and Department of Medicine, SUNY Upstate Medical University, Syracuse, New York, United States of America
| | - Anna M. Stewart-Ibarra
- Institute for Global Health and Translational Science and Department of Medicine, SUNY Upstate Medical University, Syracuse, New York, United States of America
| | - Sadie J. Ryan
- Quantitative Disease Ecology and Conservation (QDEC) Laboratory, Department of Geography and Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Erin Mordecai
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Froilán Heras
- Institute for Global Health and Translational Science and Department of Medicine, SUNY Upstate Medical University, Syracuse, New York, United States of America
| | - Efraín Beltrán
- Universidad Técnica de Machala, Machala, El Oro, Ecuador
| | - Jaime A. Costales
- Centro de Investigación para la Salud en América Latina (CISeAL), Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Marco Neira
- Centro de Investigación para la Salud en América Latina (CISeAL), Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
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Ismail S, Farner J, Couper L, Mordecai E, Lyberger K. Temperature and intraspecific variation affect host-parasite interactions. bioRxiv 2023:2023.08.24.554680. [PMID: 37662401 PMCID: PMC10473705 DOI: 10.1101/2023.08.24.554680] [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] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Parasites play key roles in regulating aquatic ecosystems, yet the impact of climate warming on their ecology and disease transmission remains poorly understood. Isolating the effect of warming is challenging as transmission involves multiple interacting species and potential intraspecific variation in temperature responses of one or more of these species. Here, we leverage a wide-ranging mosquito species and its facultative parasite as a model system to investigate the impact of temperature on host-parasite interactions and disease transmission. We conducted a common garden experiment measuring parasite growth and infection rates at seven temperatures using 12 field-collected parasite populations and a single mosquito population. We find that both free-living growth rates and infection rates varied with temperature, which were highest at 18-24.5°C and 13°C, respectively. Further, we find intraspecific variation in peak performance temperature reflecting patterns of local thermal adaptation-parasite populations from warmer source environments typically had higher thermal optima for free-living growth rates. For infection rates, we found a significant interaction between parasite population and nonlinear effects of temperature. These findings underscore the need to consider both host and parasite thermal responses, as well as intraspecific variation in thermal responses, when predicting the impacts of climate change on disease in aquatic ecosystems.
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Seetah K, Moots H, Pickel D, Van Cant M, Cianciosi A, Mordecai E, Cullen M, Maldonado Y. Global Health Needs Modernized Containment Strategies to Prepare for the Next Pandemic. Front Public Health 2022; 10:834451. [PMID: 35769777 PMCID: PMC9234159 DOI: 10.3389/fpubh.2022.834451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 04/28/2022] [Indexed: 11/13/2022] Open
Abstract
COVID-19 continues to be a public health crisis, while severely impacting global financial markets causing significant economic and social hardship. As with any emerging disease, pharmaceutical interventions required time, emphasizing the initial and continuing need for non-pharmaceutical interventions. We highlight the role of anthropological and historical perspectives to inform approaches to non-pharmaceutical interventions for future preparedness. The National Academy of Medicine, a not-for-profit, non-governmental US-based medical watchdog organization, published a key document early in the COVID-19 pandemic which points to inadequate quarantine and containment infrastructure as a significant obstacle to an effective pandemic response. In considering how to implement effective quarantine policies and infrastructure, we argue that it is essential to take a longitudinal approach to assess interventions that have been effective in past pandemics while simultaneously addressing and eliminating the negative socio-historical legacies of ineffective quarantine practices. Our overview reinforces the need for social equity and compassion when implementing containment.
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Affiliation(s)
- Krish Seetah
- Department of Anthropology, Stanford, CA, United States
- Center for Innovation in Global Health, Stanford University, Stanford, CA, United States
- Center for Population Health Sciences, Stanford School of Medicine, Stanford University, Stanford, CA, United States
- Woods Institute for the Environment, Stanford, CA, United States
| | - Hannah Moots
- Department of Human Genetics, Oriental Institute Museum, University of Chicago, Chicago, IL, United States
| | - David Pickel
- Department of Classics, Stanford University, Stanford, CA, United States
| | - Marit Van Cant
- Department of Anthropology, Stanford, CA, United States
- Belgian American Educational Foundation (B.A.E.F), New Haven, CT, United States
| | - Alessandra Cianciosi
- Department of Anthropology, Stanford, CA, United States
- Amsterdam School of Historical Studies, University of Amsterdam, Amsterdam, Netherlands
| | - Erin Mordecai
- Department of Biology, Stanford University, Stanford, CA, United States
| | - Mark Cullen
- Center for Population Health Sciences, Stanford School of Medicine, Stanford University, Stanford, CA, United States
| | - Yvonne Maldonado
- Faculty Development and Diversity, Global Health and Infectious Diseases, Department of Pediatrics, Stanford University, Stanford, CA, United States
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Johnson LR, Gramacy RB, Cohen J, Mordecai E, Murdock C, Rohr J, Ryan SJ, Stewart-Ibarra AM, Weikel D. PHENOMENOLOGICAL FORECASTING OF DISEASE INCIDENCE USING HETEROSKEDASTIC GAUSSIAN PROCESSES: A DENGUE CASE STUDY. Ann Appl Stat 2018; 12:27-66. [PMID: 38623158 PMCID: PMC11017302 DOI: 10.1214/17-aoas1090] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
In 2015 the US federal government sponsored a dengue forecasting competition using historical case data from Iquitos, Peru and San Juan, Puerto Rico. Competitors were evaluated on several aspects of out-of-sample forecasts including the targets of peak week, peak incidence during that week, and total season incidence across each of several seasons. our team was one of the winners of that competition, outperforming other teams in multiple targets/locales. In this paper we report on our methodology, a large component of which, surprisingly, ignores the known biology of epidemics at large-for example, relationships between dengue transmission and environmental factors-and instead relies on flexible nonparametric nonlinear Gaussian process (GP) regression fits that "memorize" the trajectories of past seasons, and then "match" the dynamics of the unfolding season to past ones in real-time. Our phenomenological approach has advantages in situations where disease dynamics are less well understood, or where measurements and forecasts of ancillary covariates like precipitation are unavailable, and/or where the strength of association with cases are as yet unknown. In particular, we show that the GP approach generally outperforms a more classical generalized linear (autoregressive) model (GLM) that we developed to utilize abundant covariate information. We illustrate variations of our method(s) on the two benchmark locales alongside a full summary of results submitted by other contest competitors.
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Johnson LR, Ben-Horin T, Lafferty KD, McNally A, Mordecai E, Paaijmans KP, Pawar S, Ryan SJ. Understanding uncertainty in temperature effects on vector-borne disease: a Bayesian approach. Ecology 2015; 96:203-13. [PMID: 26236905 DOI: 10.1890/13-1964.1] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Extrinsic environmental factors influence the distribution and population dynamics of many organisms, including insects that are of concern for human health and agriculture. This is particularly true for vector-borne infectious diseases like malaria, which is a major source of morbidity and mortality in humans. Understanding the mechanistic links between environment and population processes for these diseases is key to predicting the consequences of climate change on transmission and for developing effective interventions. An important measure of the intensity of disease transmission is the reproductive number R0. However, understanding the mechanisms linking R0 and temperature, an environmental factor driving disease risk, can be challenging because the data available for parameterization are often poor. To address this, we show how a Bayesian approach can help identify critical uncertainties in components of R0 and how this uncertainty is propagated into the estimate of R0. Most notably, we find that different parameters dominate the uncertainty at different temperature regimes: bite rate from 15 degrees C to 25 degrees C; fecundity across all temperatures, but especially approximately 25-32 degrees C; mortality from 20 degrees C to 30 degrees C; parasite development rate at degrees 15-16 degrees C and again at approximately 33-35 degrees C. Focusing empirical studies on these parameters and corresponding temperature ranges would be the most efficient way to improve estimates of R0. While we focus on malaria, our methods apply to improving process-based models more generally, including epidemiological, physiological niche, and species distribution models.
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