Publications by authors named "Juan Hernandez-Ortiz"

Article Synopsis
  • UAFI is a significant challenge in diagnosing tropical infections due to overlapping symptoms, necessitating accurate pathogen detection for effective treatment and outbreak management.
  • The research developed two real-time multiplex PCR assays designed to detect six overlooked pathogens causing UAFI, emphasizing efficiency and reliability in tropical regions.
  • The assays demonstrated high sensitivity and consistency, offering a cost-effective solution that can streamline laboratory work and cater to resource-limited settings.
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Platonic-solid-like particles in liquid crystals offer intriguing opportunities for engineering complex materials with tailored properties. Inspired by platonic solids' geometric simplicity and symmetry, these particles possess well-defined shapes such as cubes, tetrahedra, octahedra, dodecahedra, and icosahedra. When dispersed within nematic liquid-crystalline media, these particles interact with the surrounding medium in intricate ways, influencing the local orientational order of liquid crystal molecules.

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In early 2024, explosive outbreaks of Oropouche virus (OROV) linked to a novel lineage were documented in the Amazon Region of Brazil. We report the introduction of this lineage into Colombia and its co-circulation with another OROV lineage. Continued surveillance is needed to prevent further spread of OROV in the Americas.

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  • Mayaro Fever (MF) is caused by the Mayaro virus and has been reported in outbreaks in Latin America, particularly in Leticia, Colombia, where a fever surveillance study was conducted.
  • In a sample of 1,460 patients, most cases were linked to dengue and malaria, but 71.4% were unexplained until metagenomic sequencing detected MAYV in two patients with MF symptoms.
  • This research marks the first identification of MAYV in Colombia, indicating a need for more studies and improved surveillance to monitor its spread in the region.
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  • * A study in Colombia analyzing 170 swine specimens from 2011-2017 revealed a predominance of pandemic-like H1N1 lineage viruses, along with new reassortant and recombinant strains not previously identified in the country.
  • * The findings underscore the need for improved surveillance and biosecurity measures, especially since high swine density regions facilitate viral exchange, highlighting the importance of monitoring IAV evolution for effective vaccine strategies and health policy decisions.
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  • Equine influenza (EIV) is a viral disease affecting horses, and reporting infections is mandatory as per WOAH guidelines; this research focuses on analyzing EIV risk factors in Colombia from 2020 to 2023.
  • The study involved 188 horses with respiratory symptoms, finding a positivity rate of 33.5%, and revealed that only 12.8% were vaccinated, with high rates of quarantine and isolation practices in place.
  • Significant risk factors identified included failure to isolate infected horses and proximity to poultry, emphasizing the need for improved EIV prevention and control strategies in Colombia.
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Large DNA molecules (>20 kb) are difficult analytes prone to breakage during serial manipulations and cannot be 'rescued' as full-length amplicons. Accordingly, to present, modify and analyze arrays of large, single DNA molecules, we created an easily realizable approach offering gentle confinement conditions or immobilization via spermidine condensation for controlled delivery of reagents that support live imaging by epifluorescence microscopy termed 'Gel-Stacks.' Molecules are locally confined between two hydrogel surfaces without covalent tethering to support time-lapse imaging and multistep workflows that accommodate large DNA molecules.

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Dengue virus (DENV) is the etiological agent of dengue fever (DF), which is among the most prevalent vector-borne diseases in the tropics. In 2022, the Colombian health surveillance system reported more than 69,000 cases of DF. As part of a hospital-based fever surveillance study, acute-phase sera were collected from 4,545 patients with suspected dengue between 2020 and 2023 in three municipalities of Colombia.

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While Bacterial Artificial Chromosomes libraries were once a key resource for the genomic community, they have been obviated, for sequencing purposes, by long-read technologies. Such libraries may now serve as a valuable resource for manipulating and assembling large genomic constructs. To enhance accessibility and comparison, we have developed a BAC restriction map database.

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Background: Mansonellosis is an undermapped insect-transmitted disease caused by filarial nematodes that are estimated to infect hundreds of millions of people. Despite their prevalence, there are many outstanding questions regarding the general biology and health impacts of the responsible parasites. Historical reports suggest that the Colombian Amazon is endemic for mansonellosis and may serve as an ideal location to pursue these questions.

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Chiral liquid crystals (ChLCs) exhibit an inherent twist that originates at the molecular scale and can extend over multiple length scales when unconstrained. Under confinement, the twist is thwarted, leading to formation of defects in the molecular order that offer distinct optical responses and opportunities for colloidal driven assembly. Past studies have explored spheroidal confinement down to the nanoscopic regime, where curved boundaries produce surface defects to accommodate topological constraints and restrict the propagation of cuboidal defect networks.

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Article Synopsis
  • The first 18 months of SARS-CoV-2 infections in Colombia were marked by three waves, with the Mu variant emerging and outperforming Alpha and Gamma during the third wave from March to August 2021.
  • Using Bayesian phylodynamic inference and epidemiological modeling, the study revealed that Mu's success in Colombia stemmed from local transmission, genetic diversity, and its ability to evade immunity, even though it wasn't the most transmissible variant overall.
  • The findings emphasize that both genetic and external factors affect variant competition outcomes, and while Mu thrived in Colombia, it struggled to spread internationally due to the earlier establishment of more immune-resistant variants like Delta in those regions.
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Background: Severe acute respiratory syndrome coronavirus 2 continues to threaten public health. The virus is causing breakthrough infections in vaccinated individuals. Also, scarce information is available about cutaneous manifestations after severe acute respiratory syndrome coronavirus 2 infection.

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Understanding electrostatic interactions among dielectric bodies in the atmosphere and aerosols is central to controlling their aggregation. Polarization effects, which are frequently ignored, are crucial to determine interactions when geometrical anisotropies are present due to surface-induced charge segregation. Here, we adopt a direct integral formulation that accounts for the problem of charged dielectric bodies immersed in a continuum media to explore particle aggregation via geometrical tuning.

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Arbovirus infections are frequent causes of acute febrile illness (AFI) in tropical countries. We conducted health facility-based AFI surveillance at four sites in Colombia (Cucuta, Cali, Villavicencio, Leticia) during 2019-2022. Demographic, clinical and risk factor data were collected from persons with AFI that consented to participate in the study ( = 2,967).

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Biosecurity protocols (BP) and good management practices are key to reduce the risk of introduction and transmission of infectious diseases into the pig farms. In this observational cross-sectional study, survey data were collected from 176 pig farms with inventories over 100 sows in Colombia. We analyzed a complex survey dataset to explore the structure and identify clustering patterns using Multiple Correspondence Analysis (MCA) of swine farms in Colombia, and estimated its association with Influenza A virus detection.

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Field-effect transistors (FETs) combined with a microfluidic system allow for the electrical detection of charged materials moving in a microfluidic channel. Here, we demonstrate trench-shaped silicon FETs with the combination of a microfluidic channel that can be used for simultaneous electrical and optical detection of charged fluorescent beads. The n-channel silicon trench FETs have a maximum transconductance of 1.

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This cross-sectional study assesses the emergence and spread of the SARS-CoV-2 Mu variant compared with other variants in Antioquia State, Columbia, from July 2020 to August 2021.

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Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to cause very high morbidity and mortality throughout Latin American countries. However, few population-based seroprevalence surveys have been conducted to quantify attack rates and characterize drivers of transmission.

Methods: We conducted a population-based cross-sectional study to assess the seroprevalence of antibodies against SARS-CoV-2 in ten cities in Colombia between September and December 2020.

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Article Synopsis
  • The Omicron variant B.1.1.529 has raised concerns about its ability to evade vaccine protection and therapeutic antibodies.
  • Research using mice and hamsters revealed that B.1.1.529 caused less severe respiratory infections compared to previous SARS-CoV-2 variants, even though it binds strongly to mouse ACE2.
  • The findings indicate a milder disease response in rodents infected with B.1.1.529, which aligns with some early clinical observations in humans.
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Despite the development and deployment of antibody and vaccine countermeasures, rapidly-spreading SARS-CoV-2 variants with mutations at key antigenic sites in the spike protein jeopardize their efficacy. The recent emergence of B.1.

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Timely and accurate diagnostics are essential to fight the COVID-19 pandemic, but no test satisfies both conditions. Dogs can scent-identify the unique odors of volatile organic compounds generated during infection by interrogating specimens or, ideally, the body of a patient. After training 6 dogs to detect SARS-CoV-2 by scent in human respiratory secretions (in vitro diagnosis), we retrained 5 of them to search and find the infection by scenting the patient directly (in vivo screening).

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Article Synopsis
  • - SARS-CoV-2 has genetic diversity that can influence how easily the virus spreads and its ability to evade immunity from natural infections or vaccines.
  • - A study in Colombia identified the B.1.621 lineage of SARS-CoV-2 (a variant of interest) from genome sequencing of samples collected between January and April 2021, revealing several significant mutations in the Spike protein.
  • - The B.1.621 variant showed a rapid increase in prevalence in various regions of Colombia, raising concerns about its potential impact on public health and the effectiveness of existing immunity levels.
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