Publications by authors named "William M Souza"

Madariaga virus (MADV) and Venezuelan equine encephalitis virus (VEEV) are emerging arboviruses affecting rural and remote areas of Latin America. However, clinical and epidemiologic reports are limited, and outbreaks are occurring at an increasing frequency. We addressed the data gap by analyzing all available clinical and epidemiologic data of MADV and VEEV infections recorded since 1961 in Panama.

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Peribunyavirids produce enveloped virions with three negative-sense RNA segments comprising 10.7-12.5 kb in total.

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  • The study explores the resurgence of Oropouche fever in Brazil from 2023 to 2024, focusing on virological factors influencing the outbreak after decades of sporadic cases.
  • Researchers gathered data from various sources, analyzed serum samples from patients and previously infected individuals, and performed molecular tests to understand the virus's characteristics and behavior.
  • The findings showed an extraordinary spike in cases in 2024, with over 8,600 confirmed incidents, highlighting the virus's widespread distribution across all regions of Brazil.
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  • Western equine encephalitis virus (WEEV) caused a significant outbreak in Argentina and Uruguay from December 2023 to April 2024, with 217 human cases and 2,548 equine cases reported.
  • The investigation focused on the Rio Grande do Sul state border area between Argentina and Uruguay, utilizing epidemiologic, entomological, and genomic methods to analyze the outbreak.
  • A novel lineage of the virus, proposed as lineage C, was identified in three fatal equine cases, emphasizing the need for ongoing monitoring and equine vaccination to prevent future outbreaks.
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  • * The study included data from 2015 to 2024, revealing a dramatic rise in infections—83.2% occurring in the North—and identified a novel OROV strain that is much more virulent than the original prototype.
  • * The new OROV strain was shown to replicate significantly faster and more effectively in mammalian cells, with a notable decrease in neutralizing antibodies from individuals previously infected, indicating a potential threat to public health.
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  • A serosurvey in Senegal from 2020-2023 examined chikungunya virus (CHIKV) exposure in fruit bats.
  • Out of 671 bats tested, 13.3% showed exposure to CHIKV IgG, with the highest rates found in Eidolon helvum (18.3%) and Epomophorus gambianus (13.7%).
  • The findings indicate that these bat species are naturally exposed to the chikungunya virus.
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  • A recent outbreak of western equine encephalitis virus (WEEV) has been reported in South America, particularly in Brazil, where three horses have died from the infection.
  • Researchers sequenced the WEEV strains and discovered a new lineage responsible for these fatalities.
  • To reduce the impact of WEEV, ongoing monitoring and vaccination of horses are essential.
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We detected Mayaro virus (MAYV) in 3.4% (28/822) of febrile patients tested during 2018-2021 from Roraima State, Brazil. We also isolated MAYV strains and confirmed that these cases were caused by genotype D.

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  • Vector-borne diseases, spread by blood-feeding arthropods like mosquitoes and ticks, significantly impact global health, especially in tropical and subtropical regions.
  • Climate change affects these vectors' reproduction and distribution, which in turn influences disease transmission, but the outcomes are often complex and can vary widely.
  • The discussion in this Review includes how factors such as climate, land use, and human movement contribute to the changing patterns of vectors and their associated diseases around the world.
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  • Chikungunya virus (CHIKV) can lead to severe diseases, including chronic arthritis and, in rare cases, neurological issues and death, primarily transmitted by mosquitoes.
  • A comprehensive study revealed that deaths from CHIKV are linked to multi-organ infections, serious brain damage, and higher levels of inflammation in the body compared to survivors.
  • The research also found that CHIKV infection disrupts the blood-brain barrier, leading to increased permeability and changes in protein expression, enhancing our understanding of CHIK pathophysiology and fatal outcomes.
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Madariaga virus (MADV) and Venezuelan equine encephalitis virus (VEEV) are emerging arboviruses affecting rural and remote areas of Latin America. However, there are limited clinical and epidemiological reports available, and outbreaks are occurring at an increasing frequency. We addressed this gap by analyzing all the available clinical and epidemiological data of MADV and VEEV infections recorded since 1961 in Panama.

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In the Americas, one decade following its emergence in 2013, chikungunya virus (CHIKV) continues to spread and cause epidemics across the region. To date, 3.7 million suspected and laboratory-confirmed chikungunya cases have been reported in 50 countries or territories in the Americas.

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Since 2014, Brazil has experienced an unprecedented epidemic caused by chikungunya virus (CHIKV), with several waves of East-Central-South-African (ECSA) lineage transmission reported across the country. In 2018, Rio de Janeiro state, the third most populous state in Brazil, reported 41% of all chikungunya cases in the country. Here we use evolutionary and epidemiological analysis to estimate the timescale of CHIKV-ECSA-American lineage and its epidemiological patterns in Rio de Janeiro.

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While rodents are primary reservoirs of Venezuelan equine encephalitis virus (VEEV), their role in Madariaga virus (MADV) transmission remains uncertain, particularly given their overlapping geographic distribution. This study explores the interplay of alphavirus prevalence, rodent diversity, and land use within Darien and Western Panama provinces. A total of three locations were selected for rodent sampling in Darien province: Los Pavitos, El Real de Santa Maria and Santa Librada.

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  • In April 2023, the International Committee on Taxonomy of Viruses (ICTV) approved changes to the phylum's classification during their annual vote.
  • The update included the addition of one new family, 14 new genera, and 140 new species.
  • Additionally, the taxonomy featured the renaming of two genera and 538 species, along with the removal of one species and the abolition of four others.
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  • The Omicron subvariant BA.5 became the dominant strain globally, surpassing earlier subvariants due to its ability to evade immune responses and bind more effectively to receptors.
  • A study using male Syrian hamsters assessed how well different COVID-19 vaccine regimens, including Janssen and Pfizer/BioNTech vaccines, protect against BA.5 after primary vaccination and boosters.
  • Results showed that a single high or low dose of the Janssen vaccine offers longer-lasting immunity compared to two doses of Pfizer, and boosters like Novavax enhance immunity and reduce viral replication more effectively.
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Emerging and re-emerging viruses are a global health concern. Genome sequencing as an approach for monitoring circulating viruses is currently hampered by complex and expensive methods. Untargeted, metagenomic nanopore sequencing can provide genomic information to identify pathogens, prepare for or even prevent outbreaks.

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  • A study analyzed the immune response (specifically IgA and IgG antibodies) in COVID-19 patients, focusing on the spike and nucleocapsid proteins of the virus to relate it to disease severity.
  • The research found that hospitalized patients with severe symptoms had a significantly stronger IgG response compared to those with mild symptoms, indicating a correlation between antibody levels and disease outcome.
  • The findings suggest that tracking specific antibody responses could help in understanding disease progression and potentially improving patient outcomes.
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Background: Chikungunya virus (CHIKV) is an Aedes mosquito-borne virus that has caused large epidemics linked to acute, chronic, and severe clinical outcomes. Currently, Brazil has the highest number of chikungunya cases in the Americas. We aimed to investigate the spatiotemporal dynamics and recurrence pattern of chikungunya in Brazil since its introduction in 2013.

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Flavivirids (family ) are a group of positive-strand ribonucleic acid (RNA) viruses that pose serious risks to human and animal health on a global scale. Here, we use flavivirid-derived deoxyribonucleic acid (DNA) sequences, identified in animal genomes, to reconstruct the long-term evolutionary history of family . We demonstrate that flavivirids are >100 million years old and show that this timing can be combined with dates inferred from co-phyletic analysis to produce a cohesive overview of their evolution, distribution, and diversity wherein the main flavivirid subgroups originate in early animals and broadly co-diverge with major animal phyla.

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Background: Although hantaviruses have long been associated with rodents, they are also described in other mammalian hosts, such as shrews, moles and bats. Hantaviruses associated with bats have been described in Asian, European and Brazilian species of bats. As these mammals represent the second major mammalian order, and they are the major mammals that inhabit urban areas, it is extremely important to maintain a viral surveillance in these animals.

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  • * It was expanded to include two new families, 41 new genera, and 98 new species, along with reclassifications for 349 species.
  • * The article details the updated taxonomy of Negarnaviricota, including corrections of misspelled names for seven species.
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The family includes enterically transmitted small quasi-enveloped or non-enveloped positive-sense single-stranded RNA viruses infecting mammals and birds (subfamily ) or fish (). Hepatitis E virus (genus ) is responsible for self-limiting acute hepatitis in humans; the infection may become chronic in immunocompromised individuals and extrahepatic manifestations have been described. Avian hepatitis E virus (genus ) causes hepatitis-splenomegaly syndrome in chickens.

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