RESUMEN

Rats are major reservoirs for pathogenic Leptospira, the bacteria causing leptospirosis, particularly in urban informal settlements. However, the impact of variation in rat abundance and pathogen shedding rates on spillover transmission to humans remains unclear. This study aimed to investigate how spatial variation in reservoir abundance and pathogen pressure affect Leptospira spillover transmission to humans in a Brazilian urban informal settlement. A longitudinal eco-epidemiological study was conducted from 2013 to 2014 to characterize the spatial distribution of rat abundance and Leptospira shedding rates in rats and determine the association with human infection risk in a cohort of 2,206 community residents. Tracking plates and live-trapping were used to measure rat abundance and quantify rat shedding status and load. In parallel, four sequential biannual serosurveys were used to identify human Leptospira infections. To evaluate the role of shedding on human risk, we built three statistical models for: (1) the relative abundance of rats, (2) the shedding rate by individual rats, and (3) human Leptospira infection, in which "total shedding", obtained by multiplying the predictions from those two models, was used as a risk factor. We found that Leptospira shedding was associated with older and sexually mature rats and varied spatially and temporally-higher at valley bottoms and with seasonal rainfall (December to March). The point estimate for "total shedding" by rat populations was positive, i.e., Leptospira infection risk increased with total shedding, but the association was not significant [odds ratio (OR) = 1.1; 95% confidence interval (CI): 0.9, 1.4]. This positive trend was mainly driven by rat abundance, rather than individual rat shedding (OR = 1.8; 95% CI: 0.6, 5.4 vs. OR = 1.0; 95% CI: 0.7, 1.4]. Infection risk was higher in areas with more vegetative land cover (OR = 2.4; 95% CI: 1.2, 4.8), and when floodwater entered the house (OR = 2.4; 95% CI: 1.6, 3.4). Our findings indicate that environmental and hydrological factors play a more significant role in Leptospira spillover than rat associated factors. Furthermore, we developed a novel approach combining several models to elucidate complex links between animal reservoir abundance, pathogen shedding and environmental factors on zoonotic spillover in humans that can be extended to other environmentally transmitted diseases.

Asunto(s)

Reservorios de Enfermedades , Leptospira , Leptospirosis , Zoonosis , Animales , Humanos , Leptospirosis/epidemiología , Leptospirosis/microbiología , Leptospirosis/transmisión , Leptospira/aislamiento & purificación , Reservorios de Enfermedades/microbiología , Brasil/epidemiología , Ratas , Zoonosis/microbiología , Masculino , Femenino , Adulto , Derrame de Bacterias , Estudios Longitudinales , Persona de Mediana Edad , Factores de Riesgo , Población Urbana/estadística & datos numéricos , Adolescente , Adulto Joven

RESUMEN

A Disintegrin and Metalloproteinase 10 (ADAM10) is a crucial transmembrane protein involved in diverse cellular processes, including cell adhesion, migration, and proteolysis. ADAM10's ability to cleave over 100 substrates underscores its significance in physiological and pathological contexts, particularly in Alzheimer's disease (AD). This review comprehensively examines ADAM10's multifaceted roles, highlighting its critical function in the non-amyloidogenic processing of the amyloid precursor protein (APP), which mitigates amyloid beta (Aß) production, a critical factor in AD development. We summarize the regulation of ADAM10 at multiple levels: transcriptional, translational, and post-translational, revealing the complexity and responsiveness of its expression to various cellular signals. A standardized nomenclature for ADAM10 isoforms is proposed to improve clarity and consistency in research, facilitating better comparison and replication of findings across studies. We address the challenges in detecting ADAM10 isoforms using antibodies, advocating for standardized detection protocols to resolve discrepancies in results from different biological matrices. By highlighting these issues, this review underscores the potential of ADAM10 as a biomarker for early diagnosis and a therapeutic target in AD. By consolidating current knowledge on ADAM10's regulation and function, we aim to provide insights that will guide future research and therapeutic strategies in the AD context.

Asunto(s)

Proteína ADAM10 , Enfermedad de Alzheimer , Isoformas de Proteínas , Humanos , Enfermedad de Alzheimer/metabolismo , Proteína ADAM10/metabolismo , Animales , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Anticuerpos , Proteínas de la Membrana/metabolismo , Relevancia Clínica

RESUMEN

ABSTRACT This study aimed to provide further insight into the evolutionary dynamics of SARS-CoV-2 by analyzing the case of a 40-year-old man who had previously undergone autologous hematopoietic stem cell transplantation due to a diffuse large B-cell lymphoma. He developed a persistent SARS-CoV-2 infection lasting at least 218 days and did not manifest a humoral immune response to the virus during this follow-up period. Whole-genome sequencing and viral cultures confirmed a persistent infection with a replication-positive virus that had undergone genetic variation for at least 196 days after symptom onset.

RESUMEN

Introduction-The dynamics of SARS-CoV-2 shedding and replication in humans remain incompletely understood. Methods-We analyzed SARS-CoV-2 shedding from multiple sites in individuals with an acute COVID-19 infection by weekly sampling for five weeks in 98 immunocompetent and 25 immunosuppressed individuals. Samples and culture supernatants were tested via RT-PCR for SARS-CoV-2 to determine viral clearance rates and in vitro replication. Results-A total of 2447 clinical specimens were evaluated, including 557 nasopharyngeal swabs, 527 saliva samples, 464 urine specimens, 437 anal swabs and 462 blood samples. The SARS-CoV-2 genome sequences at each site were classified as belonging to the B.1.128 (ancestral strain) or Gamma lineage. SARS-CoV-2 detection was highest in nasopharyngeal swabs regardless of the virus strain involved or the immune status of infected individuals. The duration of viral shedding varied between clinical specimens and individual patients. Prolonged shedding of potentially infectious virus varied from 10 days up to 191 days, and primarily occurred in immunosuppressed individuals. Virus was isolated in culture from 18 nasal swab or saliva samples collected 10 or more days after onset of disease. Conclusions-Our findings indicate that persistent SARS-CoV-2 shedding may occur in both competent or immunosuppressed individuals, at multiple clinical sites and in a minority of subjects is capable of in vitro replication.

Asunto(s)

COVID-19 , Humanos , COVID-19/diagnóstico , SARS-CoV-2/genética , Prueba de COVID-19 , Manejo de Especímenes , Esparcimiento de Virus , ARN Viral/genética

RESUMEN

Abstract Asymptomatic infections with SARS-CoV-2 are associ ated with viral transmission and have a key role in the propagation of the pandemic. Understanding viral shed ding during asymptomatic infections is critical. Unfor tunately, data on asymptomatic SARS-CoV-2 infection in children is extremely limited. To determine the presence of viral viable shedding, we prospectively followed two healthy children of a family where both parents devel oped mild COVID-19 (April 2021). SARS-CoV-2 detection was made by RT-PCR and virus isolation by cell culture from saliva samples. Positive samples were sequenced to identify variants of SARS-CoV-2. Serum samples were evaluated to determine the presence of antibodies using a single enzyme-linked immunosorbent assay (ELISA, COVIDAR IgG). Both children were SARS-CoV-2 positive and asymptomatic. In addition, the virus grew in cell cul ture from saliva samples. Furthermore, one child showed viable SARS-CoV-2 for at least 17 days after the onset symptoms from his father. The recommended isolation period for asymptomatic contacts during the acquisition of data had been established for 10 days; however, this child remained with viable virus beyond that period. The positive samples from both children were consistent with B.1.1.28.1 lineage (Gamma). In both asymptomatic children, anti-Spike IgG was detected. Asymptomatic children may represent a source of infection that should not be underestimated during this pandemic.

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Resumen Las infecciones asintomáticas por SARS-CoV-2 están asociadas a la transmisión viral y tienen un papel cla ve en la propagación de la pandemia. Comprender la excreción viral durante las infecciones asintomáticas es fundamental. Desafortunadamente, los datos sobre la infección asintomática por SARS-CoV-2 en niños son extremadamente limitados. Para determinar la presencia de excreción de virus viable, se siguió prospectivamente a dos niños sanos de una familia en la que ambos padres desarrollaron COVID-19 leve (abril 2021). La detección de SARS-CoV-2 se realizó por RT-PCR y el aislamiento del virus por cultivo celular a partir de muestras de saliva. Las muestras positivas se secuenciaron para identificar variantes de SARS-CoV-2. En las muestras de suero se determinó la presencia de anticuerpos utilizando un ensayo de ELISA (COVIDAR IgG). Ambos niños fueron positivos para SARS-CoV-2 y asintomáticos. Además, el virus creció en cultivos celulares a partir de muestras de saliva. Uno de los niños mantuvo SARS-CoV-2 via bles durante al menos 17 días después de la aparición de los síntomas de su padre. El período de aislamiento recomendado para contactos asintomáticos durante la adquisición de datos se había establecido en 10 días, sin embargo, este niño permaneció con virus viable más allá de ese período. Las muestras positivas de estos niños correspondieron al linaje B.1.1.28.1 (Gamma). En ambos niños asintomáticos se detectó anticuerpos IgG anti-Spike. Concluimos que los niños asintomáticos pueden representar una fuente de infección que no debe subestimarse durante esta pandemia.

RESUMEN

Adolescents and young people are particularly vulnerable to contracting STIs, including HSV-2; furthermore, vaginal shedding of HSV-2 during pregnancy can cause vertical transmission and neonatal herpes. To evaluate the seroprevalence of HSV-2 and vaginal HSV-2 shedding in adolescent and young pregnant women, a cross-sectional study was carried out in 496 pregnant women-adolescents and young women. Venous blood and vaginal exudate samples were taken. The seroprevalence of HSV-2 was determined by ELISA and Western blot. Vaginal HSV-2 shedding was assessed by qPCR of the HSV-2 UL30 gene. The seroprevalence of HSV-2 in the study population was 8.5% (95% CI 6-11), of which 38.1% had vaginal HSV-2 shedding (95% CI 22-53). Young women presented a higher seroprevalence of HSV-2 (12.1%) than adolescents (4.3%), OR = 3.4, 95% CI 1.59-7.23. Frequent alcohol consumption was significantly associated with HSV-2 seroprevalence, OR = 2.9, 95% CI 1.27-6.99. Vaginal HSV-2 shedding is highest in the third trimester of pregnancy, but this difference is not significant. The seroprevalence of HSV-2 in adolescents and young women is similar to that previously reported in other studies. However, the proportion of women with vaginal shedding of HSV-2 is higher during the third trimester of pregnancy, increasing the risk of vertical transmission.

Asunto(s)

Herpes Genital , Herpes Simple , Recién Nacido , Humanos , Femenino , Adolescente , Embarazo , Herpesvirus Humano 2 , Mujeres Embarazadas , Herpes Genital/epidemiología , Estudios Seroepidemiológicos , México/epidemiología , Estudios Transversales , Herpes Simple/epidemiología , Esparcimiento de Virus

RESUMEN

Asymptomatic infections with SARS-CoV-2 are associated with viral transmission and have a key role in the propagation of the pandemic. Understanding viral shedding during asymptomatic infections is critical. Unfortunately, data on asymptomatic SARS-CoV-2 infection in children is extremely limited. To determine the presence of viral viable shedding, we prospectively followed two healthy children of a family where both parents developed mild COVID-19 (April 2021). SARS-CoV-2 detection was made by RT-PCR and virus isolation by cell culture from saliva samples. Positive samples were sequenced to identify variants of SARS-CoV-2. Serum samples were evaluated to determine the presence of antibodies using a single enzyme-linked immunosorbent assay (ELISA, COVIDAR IgG). Both children were SARS-CoV-2 positive and asymptomatic. In addition, the virus grew in cell culture from saliva samples. Furthermore, one child showed viable SARS-CoV-2 for at least 17 days after the onset symptoms from his father. The recommended isolation period for asymptomatic contacts during the acquisition of data had been established for 10 days; however, this child remained with viable virus beyond that period. The positive samples from both children were consistent with B.1.1.28.1 lineage (Gamma). In both asymptomatic children, anti-Spike IgG was detected. Asymptomatic children may represent a source of infection that should not be underestimated during this pandemic.

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Las infecciones asintomáticas por SARS-CoV-2 están asociadas a la transmisión viral y tienen un papel clave en la propagación de la pandemia. Comprender la excreción viral durante las infecciones asintomáticas es fundamental. Desafortunadamente, los datos sobre la infección asintomática por SARS-CoV-2 en niños son extremadamente limitados. Para determinar la presencia de excreción de virus viable, se siguió prospectivamente a dos niños sanos de una familia en la que ambos padres desarrollaron COVID-19 leve (abril 2021). La detección de SARS-CoV-2 se realizó por RT-PCR y el aislamiento del virus por cultivo celular a partir de muestras de saliva. Las muestras positivas se secuenciaron para identificar variantes de SARS-CoV-2. En las muestras de suero se determinó la presencia de anticuerpos utilizando un ensayo de ELISA (COVIDAR IgG). Ambos niños fueron positivos para SARS-CoV-2 y asintomáticos. Además, el virus creció en cultivos celulares a partir de muestras de saliva. Uno de los niños mantuvo SARS-CoV-2 viables durante al menos 17 días después de la aparición de los síntomas de su padre. El período de aislamiento recomendado para contactos asintomáticos durante la adquisición de datos se había establecido en 10 días, sin embargo, este niño permaneció con virus viable más allá de ese período. Las muestras positivas de estos niños correspondieron al linaje B.1.1.28.1 (Gamma). En ambos niños asintomáticos se detectó anticuerpos IgG anti-Spike. Concluimos que los niños asintomáticos pueden representar una fuente de infección que no debe subestimarse durante esta pandemia.

Asunto(s)

COVID-19 , SARS-CoV-2 , Niño , Humanos , Infecciones Asintomáticas , Anticuerpos Antivirales , Inmunoglobulina G

RESUMEN

BACKGROUND: Much of the world's population has been infected with SARS-CoV-2. Thus, immunity from prior infection will play a critical role in future SARS-CoV-2 transmission. We investigated the impact of infection-induced immunity on viral shedding duration and viral load. METHODS: We conducted a household cohort study in Managua, Nicaragua, with an embedded transmission study that closely monitors participants regardless of symptoms. Real-time reverse-transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assays (ELISAs) were used to measure infections and seropositivity, respectively. Blood samples were collected twice annually and surrounding household intensive monitoring periods. We used accelerated failure time models to compare shedding times. Participants vaccinated ≥14 days prior to infection were excluded from primary analyses. RESULTS: There were 600 RT-PCR-confirmed SARS-CoV-2 infections in unvaccinated participants between May 1, 2020, and March 10, 2022, with prior ELISA data. Prior infection was associated with 48% shorter shedding times (event time ratio [ETR] 0.52, 95% CI: 0.39-0.69, mean shedding: 13.7 vs. 26.4 days). A fourfold higher anti-SARS-CoV-2 spike titer was associated with 17% shorter shedding (ETR 0.83, 95% CI: 0.78-0.90). Similarly, maximum viral loads (lowest cycle threshold [CT]) were lower for previously infected individuals (mean CT 29.8 vs. 28.0, p = 4.02 × 10-3 ), for adults and children ≥10 years, but not for children 0-9 years; there was little difference in CT levels for previously infected versus naïve adults aged above 60 years. CONCLUSIONS: Prior infection-induced immunity was associated with shorter viral shedding and lower viral loads, which may be important in the transition from pandemic to endemicity.

Asunto(s)

COVID-19 , Adulto , Niño , Humanos , COVID-19/epidemiología , SARS-CoV-2 , Estudios de Cohortes , Esparcimiento de Virus , Prueba de COVID-19

RESUMEN

Abstract: After four months of fighting the pandemic, the city of São Paulo, Brazil, entered a phase of relaxed social distancing measures in July 2020. Simultaneously, there was a decline in the social distancing rate and a reduction in the number of cases, fatalities, and hospital bed occupancy. To understand the pandemic dynamics in the city of São Paulo, we developed a multi-agent simulation model. Surprisingly, the counter-intuitive results of the model followed the city's reality. We argue that this phenomenon could be attributed to local bubbles of protection that emerged in the absence of contagion networks. These bubbles reduced the transmission rate of the virus, causing short and temporary reductions in the epidemic curve - but manifested as an unstable equilibrium. Our hypothesis aligns with the virus spread dynamics observed thus far, without the need for ad hoc assumptions regarding the natural thresholds of collective immunity or the heterogeneity of the population's transmission rate, which may lead to erroneous predictions. Our model was designed to be user-friendly and does not require any scientific or programming expertise to generate outcomes on virus transmission in a given location. Furthermore, as an input to start our simulation model, we developed the COVID-19 Protection Index as an alternative to the Human Development Index, which measures a given territory vulnerability to the coronavirus and includes characteristics of the health system and socioeconomic development, as well as the infrastructure of the city of São Paulo.

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Resumo: Após quatro meses lutando contra a pandemia, a cidade de São Paulo, Brasil, entrou em uma fase de flexibilização das medidas de distanciamento social em julho de 2020. Simultaneamente, houve queda na taxa de distanciamento social e redução no número de casos, mortes e ocupação de leitos hospitalares. Um modelo de simulação multiagente foi desenvolvido para entender a dinâmica da pandemia na cidade de São Paulo. Ao contrário do esperado, os resultados contraintuitivos do modelo acompanharam a realidade da cidade. Argumentamos que este fenômeno pode ser atribuído às bolhas locais de proteção que surgiram na ausência de redes de contágio. Estas bolhas reduziram a taxa de transmissão do vírus, causando reduções curtas e temporárias na curva epidêmica - mas se manifestaram como um equilíbrio instável. Nossa hipótese está alinhada com a dinâmica da propagação do vírus observada até o momento, sem a necessidade de suposições ad hoc sobre limiares de imunidade coletiva natural ou heterogeneidade da taxa de transmissão da população, o que pode levar a previsões errôneas. Nosso modelo foi projetado para ser fácil de usar e não requer nenhum conhecimento científico ou de programação para gerar resultados sobre a transmissão do vírus em um determinado local. Além disso, como insumo para iniciar nosso modelo de simulação, desenvolvemos o Índice de Proteção contra a COVID-19 como alternativa ao Índice de Desenvolvimento Humano, que mede a vulnerabilidade de um determinado território ao coronavírus e inclui características do sistema de saúde e do desenvolvimento socioeconômico, além da infraestrutura da cidade de São Paulo.

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Resumen: Tras cuatro meses luchando contra la pandemia, la ciudad de São Paulo, Brasil, empezó una fase de flexibilización de las medidas de alejamiento social en julio de 2020. A la vez, hubo una reducción en la tasa de alejamiento social y en el número de casos, muertes y ocupación de camas en los hospitales. Se desarrolló un modelo de simulación multiagente para entender la dinámica de la pandemia en la ciudad de São Paulo. Diferente de lo esperado, los resultados contradictorios del modelo reflejaron la realidad de la ciudad. Sostenemos que se puede atribuir este fenómeno a las burbujas locales de protección que surgieron durante la ausencia de redes de contagio. Estas burbujas redujeron la tasa de transmisión del virus, reduciendo de forma corta y temporal la curva epidémica -pero se manifestaron como un equilibrio inestable. Nuestra hipótesis se alinea con la dinámica de la propagación del virus observada hasta el momento, sin la necesidad de suposiciones ad hoc sobre umbrales de inmunidad colectiva natural o heterogeneidad de la tasa de transmisión de la población, lo que puede provocar previsiones equivocadas. Nuestro modelo se proyectó para ser fácil de usar y no necesita ningún conocimiento científico o de programación para generar resultados sobre la transmisión del virus en un determinado local. Además, como insumo para iniciar nuestro modelo de simulación, desarrollamos el Índice de Protección contra la COVID-19 como una alternativa al Índice de Desarrollo Humano, que mide la vulnerabilidad de un determinado territorio al coronavirus e incluye características del sistema de salud y del desarrollo socioeconómico, además de la infraestructura de la ciudad de São Paulo.

RESUMEN

The present work recorded the impact of using Mycoplasma gallisepticum vaccines on post-vaccinal response and protection against challenge with Newcastle disease virus. Specific pathogen-free chickens were divided into eight groups of forty chickens each. Group G1 was vaccinated with Mycoplasma gallisepticum live attenuated and Mycoplasma gallisepticum inactivated vaccines. Group G2 was vaccinated with Mycoplasma gallisepticum live attenuated, Mycoplasma gallisepticum inactivated and Newcastle disease inactivated vaccines. Group G3 was vaccinated with Mycoplasma gallisepticum live attenuated vaccine. Group G4 was vaccinated with Mycoplasma gallisepticum live attenuated and Newcastle disease inactivated vaccines. Group G5 was vaccinated with Mycoplasma gallisepticum inactivated vaccine. Group G6 was vaccinated with Mycoplasma gallisepticum inactivated and Newcastle disease inactivated vaccines. Group G7 was vaccinated with Newcastle disease inactivated vaccine. Group G8 was kept as non-vaccinated control. The Newcastle disease hemagglutination inhibition antibodies and mortality percentages were measured. Group G7 recorded the best protective Newcastle disease hemagglutination inhibition antibody titer (7 log2). Group G2 recorded a marginal satisfactory antibody titer (6 log2) after vaccination by the three tested vaccines. The remaining groups revealed unsatisfactory titers ranged from 0-5. The protection levels for G2, G4, G6 and G7 ranged from 70percent to 100percent, but only G2 and G7 were considered protected. G1, G3, G5 and G8 showed typical clinical signs of Newcastle disease. The Mycoplasma gallisepticum vaccines couldn't improve the response to Newcastle disease inactivated vaccine. The results suggest that Mycoplasma gallisepticum vaccination is immunosuppressive rather than immunomodulatory in Newcastle disease vaccination(AU)

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En el presente trabajo se registró el impacto de la utilización de vacunas contra Mycoplasma gallisepticum sobre la respuesta posvacunal y la protección frente al reto con el virus de la enfermedad de Newcastle. Pollos libres de patógenos específicos se distribuyeron en ocho grupos de cuarenta pollos cada uno. El grupo G1 se vacunó con vacunas vivas atenuadas e inactivadas contra Mycoplasma gallisepticum. Al grupo G2 se le aplicaron las vacunas: viva atenuada contra Mycoplasma gallisepticum, inactivada contra Mycoplasma gallisepticum e inactivada contra la enfermedad de Newcastle. El grupo G3 se inmunizó con la vacuna viva atenuada contra Mycoplasma gallisepticum; el G4, con las vivas atenuadas contra Mycoplasma gallisepticum e inactivada contra la enfermedad de Newcastle; el G5, con la vacuna inactivada contra Mycoplasma gallisepticum; el G6 con las vacunas inactivadas contra Mycoplasma gallisepticum y la enfermedad de Newcastle; el G7, con la vacuna inactivada contra la enfermedad de Newcastle y el G8 se mantuvo como control no vacunado. Se midieron los anticuerpos de inhibición de la hemaglutinación contra el virus de la enfermedad de Newcastle y los porcentajes de mortalidad. El grupo G7 registró el mejor título de anticuerpos inhibidores de la hemaglutinación contra la enfermedad de Newcastle (7 log2). El grupo G2 registró un título de anticuerpos marginalmente satisfactorio (6 log2) tras la vacunación con las tres vacunas ensayadas. Los demás grupos revelaron títulos insatisfactorios que oscilaban entre 0 y 5. Los niveles de protección de los grupos G2, G4, G6 y G7 oscilaron entre el 70 por ciento y el 100 por ciento, pero sólo G2 y G7 se consideraron protegidos. Los grupos G1, G3, G5 y G8 mostraron signos clínicos típicos de la enfermedad de Newcastle. Las vacunas contra Mycoplasma gallisepticum no pudieron mejorar la respuesta a la vacuna inactivada contra la enfermedad de Newcastle. Los resultados revelan que la vacunación con Mycoplasma gallisepticum es más inmunosupresora que inmunomoduladora en la vacunación contra la enfermedad de Newcastle(AU)

Asunto(s)

Animales , Enfermedades de las Aves de Corral , Pollos , Esparcimiento de Virus , Conservación de Alimentos/métodos , Infecciones por Mycoplasma/mortalidad , Enfermedad de Newcastle/mortalidad , Egipto

RESUMEN

The question whether or not tropical lianas infest host trees randomly or they exert host selection has implications for the structure and dynamics of tropical rainforests, particularly if colonization by lianas impacts host fitness. In this study, we present evidence that the Neotropical liana Marcgravia longifolia (Marcgraviaceae) infests host trees non-randomly. We identified host trees to species or genus level for 87 of the 100 M. longifolia individuals found in the study area of the Estación Biológica Quebrada Blanco (EBQB) in north-eastern Peruvian Amazonia. Data on host availability were taken from two 1-ha plots sampled at EBQB as part of a large-scale tree inventory in western Amazonia. Of the total of 88 tree genera with two or more individuals present in the inventory, 18 were represented amongst hosts. Host genera with a probability of colonization higher than expected by chance were Eschweilera (Lecythidaceae), Pouteria (Sapotaceae), Brosimum (Moraceae), and Hymenaea (Fabaceae). These findings suggest that M. longifolia exerts some level of host selectivity, but the mechanisms for this are completely unknown. Given the large number of animal species (41 bird species, three primate species) that are dispersing the seeds of M. longifolia and that have diverse ecological strategies, directed seed dispersal is unlikely to account for the observed patterns of host infestation.

Asunto(s)

Bosque Lluvioso , Clima Tropical , Animales , Probabilidad , Semillas , Perú

RESUMEN

BACKGROUND: Chikungunya is a viral disease that is transmitted by mosquitoes. It is characterized by an acute onset of fever and severe arthralgia. METHODS: We describe six cases of acute and post-acute chikungunya in which viral RNA was detected in semen. CONCLUSIONS: The most prolonged detection period was 56 days after illness onset. We attempted to cultivate positive semen samples, but virus isolation was unsuccessful in all cases.

Asunto(s)

Fiebre Chikungunya , Virus Chikungunya , Animales , Virus Chikungunya/genética , Humanos , ARN Viral/genética , Semen , Esparcimiento de Virus

RESUMEN

ANTECEDENTES Y OBJETIVO Han pasado 2 años y medio desde que la Organización Mundial de la Salud decretó emergencia sanitaria por la pandemia ocasionada por SARS-CoV-2. Durante este tiempo, se han presentado una serie de desafíos para evitar su propagación, uno de ellos corresponde a las mutaciones y cambios que ha sufrido el virus. En noviembre de 2021 se notificó la variante Ómicron B.1.1.529, que presenta algunas mutaciones de preocupación, asociándose con mayor transmisibilidad y menor susceptibilidad a los anticuerpos neutralizantes. En este contexto la Jefatura de la División de Planificación Sanitaria solicita este reporte breve de evidencia con el objetivo de conocer el período de excreción viral e infectividad de la variante Ómicron. METODOLOGÍA Se buscaron revisiones sistemáticas que respondieron la pregunta en las bases de datos MEDLINE y EMBASE a través de OVID y en Epistemonikos, con fecha 30 de agosto 2022. Debido a no encontrarse evidencia en los motores de búsqueda seleccionados, se realizó una búsqueda en Google académico, sin embargo, tampoco fue identificada evidencia alguna. Se incluyen revisiones sistemáticas, estudios que describieron o midieran los períodos de infectividad y excreción de la variante Ómicron del virus SARS-CoV-2. Se excluyen períodos de infectividad y excreción de otras variantes del Virus SARS-CoV-2. RESULTADOS -No se encontró evidencia que describiera el periodo de infectividad y excreción del virus en personas contagiadas con SARS-COV-2 variante Ómicron.

Asunto(s)

Virulencia , Chile , Liberación del Virus , COVID-19 , Virus , Organización Mundial de la Salud , Mutación

RESUMEN

Chronically immunosuppressed patients infected with SARS-CoV-2 often experience prolonged virus shedding, and may pave the way to the emergence of mutations that render viral variants of concern (VOC) able to escape immune responses induced by natural infection or by vaccination. We report herein a SARS-CoV-2+ cancer patient from the beginning of the COVID-19 pandemic whose virus quasispecies across multiple timepoints carried several immune escape mutations found in more contemporary VOC, such as alpha, delta and omicron, that appeared to be selected for during infection. We hypothesize that immunosuppressed patients may represent the source of VOC seen throughout the COVID-19 pandemics.

RESUMEN

Background: COVID-19 pandemic continues to be a priority in public health worldwide, and factors inherent to SARS-CoV-2 pathogenesis and genomic characteristics are under study. Investigations that evaluate possible risk factors for infection, clinical manifestations, and viral shedding in different specimens also need to clarify possible associations with COVID-19 prognosis and disease outcomes. Study design: In this study, we evaluated SARS-CoV-2 positivity and estimated viral loads by real-time RT-PCR in stool, sera, and urine samples from 35 patients, with a positive SARS-CoV-2 RNA molecular test in respiratory sample, attended at a University COVID-19 referral hospital in Goiania, Goias, Brazil. Whole-genome sequencing was also performed in samples with higher viral load. Results: The positivity index was 51.43%, 14.28%, and 5.71% in stool, sera, and urine specimens, respectively. The median viral load was 8.01 × 106 GC/g, 2.03 × 106 GC/mL, and 1.36 × 105 GC/mL in stool, sera, and urine, respectivelly. Of all patients, 88.57% had previous comorbidities, and 48.39% of them had detectable SARS-CoV-2 RNA in at least one type of clinical specimen evaluated by this study (stool, sera or urine). A higher viral load was observed in patients with more than two previous comorbidities and that were classified as severe or critical conditions. Samples with the highest viral loads were sequenced and characterized as B.1.1.33 variant. Conclusion: We conclude that SARS-CoV-2 RNA is present in more than one type of clinical specimen during the infection, and that the most critical patients had detectable viral RNA in more than one clinical specimen at the same time point.

RESUMEN

RESEARCH HIGHLIGHTSProgeny from vaccinated 30-week-old breeders presented less SH in caecal content compared to the control.High titres of maternal anti-Salmonella IgY could be associated with lower SH faecal shedding.

Asunto(s)

Enfermedades de las Aves de Corral , Salmonelosis Animal , Vacunas contra la Salmonella , Salmonella enterica , Animales , Vacunas Bacterianas , Pollos , Enfermedades de las Aves de Corral/prevención & control , Salmonelosis Animal/prevención & control , Serogrupo

RESUMEN

Coronavirus disease 2019 (COVID-19) is transmitted person-to-person mainly by close contact or droplets from respiratory tract. However, the actual time of viral shedding is still uncertain as well as the different routes of transmission. We aimed to characterize RNA shedding from nasopharyngeal and rectal samples in prolonged cases of mild COVID-19 in young male soldiers. Seventy patients from three different military locations were monitored after recommending to follow more strict isolation measures to prevent the spread of the virus. Then, nasopharyngeal, rectal, and blood samples were taken. SARS-CoV-2 RNA was detected by RT-PCR and specific antibodies by chemiluminescent immunoassays. The median nucleic acid conversion time (NACT) was 60 days (IQR: 7-85 days). Rectal swabs were taken in 60 % of patients. Seven patients (10 %) were positive in nasopharyngeal and rectal swabs, and five (7.14 %) remained positive in rectal swabs, but negative in nasopharyngeal samples. Four patients (5.71 %) that had been discharged, were positive again after 15 days. No significant difference was found in nucleic acid conversion time between age groups nor clinical classification. Maintaining distancing among different positive patients is essential as a possible re-exposure to the virus could cause a longer nucleic acid conversion time in SARS-COV-2 infections.

Asunto(s)

Anticuerpos Antivirales/sangre , COVID-19 , Inmunoglobulina G/sangre , ARN Viral/análisis , COVID-19/diagnóstico , COVID-19/prevención & control , Brotes de Enfermedades , Humanos , Masculino , Personal Militar , SARS-CoV-2 , Esparcimiento de Virus

RESUMEN

OBJECTIVES: The aim of this study was to evaluate the occurrence of human bocavirus (HBoV) and to determine viral loads in samples of patients admitted for allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: Fecal and serum samples were collected from 19 patients, during a 24-month period. Samples were screened by quantitative polymerase chain reaction TaqMan assay, with specific probe and primers targeting the NP1 gene of all HBoVs genotypes (HBoV-1 to - 4), and viral loads were determined using serial dilutions of a recombinant plasmid. RESULTS: HBoV DNA was detected in 42.1% (8 of 19) of the patients in at least one type of sample (feces and/or serum) during the study period, with 75% (6 of 8) of the patients being positive in both types of sample. Viral shedding in feces had a median of 26 days (range, 5 to 121) and viremia was detected in 87.5% (7 of 8) of the patients. The HBoV loads in fecal samples were higher than in sera and, in most cases, HBoV was detected earlier in fecal than in sera samples. In six HBoV-positive patients (6 of 8) diarrhea was observed concomitantly to viral detection in fecal samples. CONCLUSIONS: A high frequency and loads of HBoV in allo-HSCT recipients was observed, especially in fecal samples. Positivity in fecal samples was an early predictor of HBoV presence.

Asunto(s)

Heces/virología , Trasplante de Células Madre Hematopoyéticas , Bocavirus Humano/genética , Infecciones por Parvoviridae/virología , Viremia/sangre , Adolescente , Adulto , Brasil , Femenino , Genotipo , Hospitalización , Bocavirus Humano/aislamiento & purificación , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Carga Viral , Esparcimiento de Virus , Adulto Joven

RESUMEN

Natural herbivore populations have experienced uninterrupted pressures from direct and evident domestic-wildlife interactions and competition, to indirect or less obvious ones such as pathogen transmission. Thus, pathogen spillover between wild and domestic animals is a constant concern because the domestic-wildlife interface represents the ecological frontier in which pathogen transmission takes place in both directions. In Patagonian steppe communities, extensive sheep ranching and guanaco (Lama guanicoe) populations coexist, and guanaco have shown to be infected by pathogens such as Mycobacterium avium subspecies paratuberculosis (MAP) likely transmitted from livestock. MAP causes chronic enteritis and affects mostly domestic ruminants. We evaluated MAP prevalence and pathogen shedding in both species' faeces collected in non-shared and shared sites according to presence/absence of sheep and guanaco along a year, in four different seasons (autumn, winter, and spring 2018, and summer 2019). Our results indicate that MAP circulates in both sheep and guanaco populations with self-sustained transmission; however, both species differ in their levels of competence. We detected higher pathogen shedding in sites occupied by sheep, suggesting that sheep populations may be the main source of infection for susceptible animals due to their large numbers which drive MAP dynamics.

Asunto(s)

Camélidos del Nuevo Mundo , Reservorios de Enfermedades , Mycobacterium avium subsp. paratuberculosis , Paratuberculosis , Animales , Animales Salvajes/microbiología , Reservorios de Enfermedades/microbiología , Reservorios de Enfermedades/veterinaria , Paratuberculosis/microbiología , Paratuberculosis/transmisión , Ovinos , Enfermedades de las Ovejas/microbiología , Enfermedades de las Ovejas/transmisión

RESUMEN

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is caused by a respiratory virus with a wide range of manifestations, varying from asymptomatic to fatal cases, with a generally short outcome. However, some individuals present long-term viral shedding. We monitored 38 individuals who were mildly affected by the SARS-CoV-2 infection. Out of the total studied population, three (7.9%) showed atypical events regarding the duration of positivity for viral RNA detection. In one of these atypical cases, a previously HIV-positive male patient presented a SARS-CoV-2 RNA shedding and subgenomic RNA (sgRNA) detected from the upper respiratory tract, respectively, for 232 and 224 days after the onset of the symptoms. The SARS-CoV-2 B.1.1.28 lineage, one of the most prevalent in Brazil in 2020, was identified in this patient in three serial samples. Interestingly, the genomic analyses performed throughout the infectious process showed an increase in the genetic diversity of the B.1.1.28 lineage within the host itself, with viral clearance occurring naturally, without any intervention measures to control the infection. Contrasting widely spread current knowledge, our results indicate that potentially infectious SARS-CoV-2 virus might be shed by much longer periods by some infected patients. This data call attention to better adapted non-pharmacological measures and clinical discharge of patients aiming at preventing the spread of SARS-CoV-2 to the population.