Publications by authors named "Samuel Yingst"

Article Synopsis
  • * Our findings identified new or previously unclassified viruses, including murine adenovirus 4 and two new species from the paramyxovirus and picornavirus families.
  • * The study highlights rodents as significant carriers for potential zoonotic viruses, which could pose risks to human health in the future.
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SARS-CoV-2 serosurveys help estimate the extent of transmission and guide the allocation of COVID-19 vaccines. We measured SARS-CoV-2 seroprevalence among women attending ANC clinics to assess exposure trends over time in Zambia. We conducted repeated cross-sectional SARS-CoV-2 seroprevalence surveys among pregnant women aged 15-49 years attending their first ANC visits in four districts of Zambia (two urban and two rural) during September 2021-September 2022.

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The US President's Emergency Plan for AIDS Relief (PEPFAR) supports molecular HIV and tuberculosis diagnostic networks and information management systems in low- and middle-income countries. We describe how national programs leveraged these PEPFAR-supported laboratory resources for SARS-CoV-2 testing during the COVID-19 pandemic. We sent a spreadsheet template consisting of 46 indicators for assessing the use of PEPFAR-supported diagnostic networks for COVID-19 pandemic response activities during April 1, 2020, to March 31, 2021, to 27 PEPFAR-supported countries or regions.

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During the July 2020 first wave of severe acute respiratory syndrome coronavirus 2 in Zambia, PCR-measured prevalence was 13.4% among outpatients at health facilities, an absolute difference of 5.7% compared with prevalence among community members.

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Background: Healthcare workers (HCWs) in Zambia have become infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19). However, SARS-CoV-2 prevalence among HCWs is not known in Zambia.

Methods: We conducted a cross-sectional SARS-CoV-2 prevalence survey among Zambian HCWs in 20 health facilities in 6 districts in July 2020.

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Background: Between March and December, 2020, more than 20 000 laboratory-confirmed cases of SARS-CoV-2 infection were reported in Zambia. However, the number of SARS-CoV-2 infections is likely to be higher than the confirmed case counts because many infected people have mild or no symptoms, and limitations exist with regard to testing capacity and surveillance systems in Zambia. We aimed to estimate SARS-CoV-2 prevalence in six districts of Zambia in July, 2020, using a population-based household survey.

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Article Synopsis
  • COVID-19 cases in Zambia began in March 2020, with a significant rise starting in mid-December, particularly after the identification of the B.1.351 variant strain from South Africa.
  • The B.1.351 variant, linked to increased transmissibility, spread quickly from South Africa to other countries, including Zambia, causing a dramatic surge in cases.
  • By January 10, 2021, Zambia experienced a 16-fold increase in daily COVID-19 cases, from 44 to 700, coinciding with the presence of the B.1.351 variant in the region.
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Zambia is a landlocked, lower-middle income country in southern Africa, with a population of 17 million (1). The first known cases of coronavirus disease 2019 (COVID-19) in Zambia occurred in a married couple who had traveled to France and were subject to port-of-entry surveillance and subsequent remote monitoring of travelers with a history of international travel for 14 days after arrival. They were identified as having suspected cases on March 18, 2020, and tested for COVID-19 after developing respiratory symptoms during the 14-day monitoring period.

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Immediately before deployment (Fall 2012) and after deployment (Spring 2013) in support of United Nations peacekeeping operations, Mongolian Armed Forces medical personnel obtained serum samples from the first contingent of Mongolian peacekeepers deploying to South Sudan to monitor serologic evidence of exposure to diseases that cause acute febrile illness. A total of 632 paired samples were tested for IgG antibody for the following (number of seroconversions in parentheses): Rickettsia (spotted fever and typhus groups) (25), West Nile fever virus (WNV) (23), Coxiella burnetii (causative agent of Q fever) (12), dengue virus (8), leptospirosis (6), chikungunya virus (0), Congo-Crimean hemorrhagic fever virus (0), Japanese encephalitis virus (0), and Rift Valley fever virus (0). There was also evidence of exposure to WNV, C.

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This study has determined the proportional seropositivity of two zoonotic diseases, Q fever and brucellosis, and bluetongue virus (BTV) which is nonzoonotic, in five provinces of Lao People's Democratic Republic (PDR) (Loungphabang, Luangnumtha, Xayaboury, Xiengkhouang, and Champasak, and Vientiane Province and Vientiane capital). A total of 1,089 samples from buffalo, cattle, pigs, and goats were tested, with seropositivity of BTV (96.7%), Q fever (1.

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Objective: To measure prevalence of prior/current Plasmodium vivax and Plasmodium falciparum (PV and PF), Brucella spp. (BR), dengue virus (DENV), Leishmania donovani (visceral leishmaniasis; VL), and Crimean-Congo hemorrhagic fever (CCHF) virus exposure among Afghan National Army (ANA) recruits.

Methods: Randomly chosen, nationally representative serum samples from consenting men aged 18-40 years and who were screened between February 2010 and January 2011 were tested, with ∼25 samples/province.

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Burkholderia mallei is a Gram-negative bacillus that causes a pneumonic disease known as glanders in equids and humans, and a lymphatic infection known as farcy, primarily in equids. With the potential to infect humans by the respiratory route, aerosol exposure can result in severe, occasionally fatal, pneumonia. Today, glanders infections in humans are rare, likely due to less frequent contact with infected equids than in the past.

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Background: Acute febrile illness is common among those seeking medical care and is frequently treated empirically with the underlying illness remaining undiagnosed in resource-poor countries. A febrile illness study was conducted 2009-2010 to identify known and unknown pathogens circulating in Nepal.

Method: Study methods included diagnostic testing and preliminary ELISA screening of acute and convalescent samples for diseases both known and unknown to be circulating in Nepal, including West Nile virus (WNV).

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Bangkok, Thailand, is a city considered to be at low risk for melioidosis. We describe 10 goats that died of melioidosis in Bangkok. Half of them were born and reared in the city.

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CD8+ T cells have been reported to play an important role in defense against B. abortus infection in mouse models. In the present report, we use CD8 knockout mice to further elucidate the role of these cells in protection from B.

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Aerosolized Burkholderia pseudomallei, the causative agent of melioidosis, can infect many species of mammals (including humans), causing rapid, severe pneumonia with high mortality. Diagnosis in humans is challenging, as few organisms can be detected in blood or other non-invasive samples. Although it cannot be said that the model is established, studies to date indicate that rhesus macaques may represent a good model of human melioidosis.

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The government of Afghanistan, with international partners and donors, has achieved substantial public health improvements during the past 8 years. But a critical gap remains: capacities to detect and respond to disease outbreaks that could constitute a public health emergency of international concern, as required by the International Health Regulations (IHR). The Afghan Ministry of Public Health seeks to build these capacities, but conflict and scarcity of resources hinder public health surveillance and response, diagnostic laboratory and clinical management capacity is limited, and massive international population movements could permit outbreaks to cross international borders.

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We conducted a prospective cohort study to determine prevalence and incidence of West Nile virus (WNV) in Egypt. Cohorts were established in Upper (UE), Middle (ME), and Lower (LE) Egypt. Additionally, a cross-sectional serosurvey was performed in the North (NS) and South (SS) Sinai.

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The US Centers for Disease Control and Prevention lists Brucella as a potential bioterrorism threat requiring enhanced diagnostic capacity and surveillance (http://emergency.cdc.gov/bioterrorism/).

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Zoonotic microbes have historically been, and continue to emerge as, threats to human health. The recent outbreaks of highly pathogenic avian influenza virus in bird populations and the appearance of some human infections have increased the concern of a possible new influenza pandemic, which highlights the need for broad-spectrum detection methods for rapidly identifying the spread or outbreak of all variants of avian influenza virus. In this study, we demonstrate that high-density resequencing pathogen microarrays (RPM) can be such a tool.

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An outbreak of Q fever occurred in 22 (58%) of 38 Marines deployed to Iraq in 2005. Fever (in 100% of patients), respiratory symptoms (76%), and gastrointestinal symptoms (53%) were common. Possible risk factors included dust and exposure to animals and ticks.

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Meningitis and/or encephalitis can pose a serious public health problem especially during outbreaks. A rapid and accurate diagnosis is important for effective earlier treatment. This study aimed to identify the possible microbial causes of meningitis and/or encephalitis cases.

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