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1. Warming temperatures could expose more than 1.3 billion new people to Zika virus risk by 2050

   https://doi.org/10.1111/gcb.15384  

   Ryan, Sadie J.; Carlson, Colin J.; Tesla, Blanka; Bonds, Matthew H.; Ngonghala, Calistus N.; Mordecai, Erin A.; Johnson, Leah R.; Murdock, Courtney C. (October 2020, Global Change Biology)

   Abstract In the aftermath of the 2015 pandemic of Zika virus (ZIKV), concerns over links between climate change and emerging arboviruses have become more pressing. Given the potential that much of the world might remain at risk from the virus, we used a previously established temperature‐dependent transmission model for ZIKV to project climate change impacts on transmission suitability risk by mid‐century (a generation into the future). Based on these model predictions, in the worst‐case scenario, over 1.3 billion new people could face suitable transmission temperatures for ZIKV by 2050. The next generation will face substantially increased ZIKV transmission temperature suitability in North America and Europe, where naïve populations might be particularly vulnerable. Mitigating climate change even to moderate emissions scenarios could significantly reduce global expansion of climates suitable for ZIKV transmission, potentially protecting around 200 million people. Given these suitability risk projections, we suggest an increased priority on research establishing the immune history of vulnerable populations, modeling when and where the next ZIKV outbreak might occur, evaluating the efficacy of conventional and novel intervention measures, and increasing surveillance efforts to prevent further expansion of ZIKV. 

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2. Effects of changes in temperature on Zika dynamics and control

   https://doi.org/10.1098/rsif.2021.0165  

   Ngonghala, Calistus N.; Ryan, Sadie J.; Tesla, Blanka; Demakovsky, Leah R.; Mordecai, Erin A.; Murdock, Courtney C.; Bonds, Matthew H. (May 2021, Journal of The Royal Society Interface)

   null (Ed.)

   When a rare pathogen emerges to cause a pandemic, it is critical to understand its dynamics and the impact of mitigation measures. We use experimental data to parametrize a temperature-dependent model of Zika virus (ZIKV) transmission dynamics and analyse the effects of temperature variability and control-related parameters on the basic reproduction number ( R 0 ) and the final epidemic size of ZIKV. Sensitivity analyses show that these two metrics are largely driven by different parameters, with the exception of temperature, which is the dominant driver of epidemic dynamics in the models. Our R 0 estimate has a single optimum temperature (≈30°C), comparable to other published results (≈29°C). However, the final epidemic size is maximized across a wider temperature range, from 24 to 36°C. The models indicate that ZIKV is highly sensitive to seasonal temperature variation. For example, although the model predicts that ZIKV transmission cannot occur at a constant temperature below 23°C (≈ average annual temperature of Rio de Janeiro, Brazil), the model predicts substantial epidemics for areas with a mean temperature of 20°C if there is seasonal variation of 10°C (≈ average annual temperature of Tampa, Florida). This suggests that the geographical range of ZIKV is wider than indicated from static R 0 models, underscoring the importance of climate dynamics and variation in the context of broader climate change on emerging infectious diseases. 

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3. Analytical methods for detection of Zika virus

   https://doi.org/10.1557/mrc.2017.20  

   Yang, Kai-Hung; Narayan, Roger J. (March 2017, MRS Communications)

   Due to the recent outbreak of the Zika virus (ZIKV) in several regions, rapid, and accurate methods to diagnose Zika infection are in demand, particularly in regions that are on the frontline of a ZIKV outbreak. In this paper, three diagnostic methods for ZIKV are considered. Viral isolation is the gold standard for detection; this approach can involve incubation of cell cultures. Serological identification is based on the interactions between viral antigens and immunoglobulin G or immunoglobulin M antibodies; cross-reactivity with other types of flaviviruses can cause reduced specificity with this approach. Molecular confirmation, such as reverse transcription polymerase chain reaction (RT–PCR), involves reverse transcription of RNA and amplification of DNA. Quantitative analysis based on real-time RT–PCR can be undertaken by comparing fluorescence measurements against previously developed standards. A recently developed programmable paper-based detection approach can provide low-cost and rapid analysis. These viral identification and viral genetic analysis approaches play crucial roles in understanding the transmission of ZIKV. 

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4. Use of Twitter data to improve Zika virus surveillance in the United States during the 2016 epidemic

   Shahir Masri, Jianfeng Jia (April 2019, BMC public health)

   Zika virus (ZIKV) is an emerging mosquito-borne arbovirus that can produce serious public health consequences. In 2016, ZIKV caused an epidemic in many countries around the world, including the United States. ZIKV surveillance and vector control is essential to combating future epidemics. However, challenges relating to the timely publication of case reports significantly limit the effectiveness of current surveillance methods. In many countries with poor infrastructure, established systems for case reporting often do not exist. Previous studies investigating the H1N1 pandemic, general influenza and the recent Ebola outbreak have demonstrated that time- and geo-tagged Twitter data, which is immediately available, can be utilized to overcome these limitations. 

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5. High prevalence of Zika virus infection in populations of Aedes aegypti from South-western Ecuador

   https://doi.org/10.1371/journal.pntd.0011908  

   López-Rosero, Andrea; Sippy, Rachel; Stewart-Ibarra, Anna M; Ryan, Sadie J; Mordecai, Erin; Heras, Froilán; Beltrán, Efraín; Costales, Jaime A; Neira, Marco (January 2024, PLOS Neglected Tropical Diseases)

   Bonizzoni, Mariangela (Ed.)

   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.aegyptimosquitoes 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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