Avanços no entendimento da patogenia da covid-19: uma revisão / Advances in understanding covid-19 pathogenesis: a review / Avances en la comprensión de la patogenia de la covid-19: una revisión

Introdução: O SARS-CoV-2, causador da pandemia por Doença por Coronavirus 2019 (COVID-19) gerou desafios à saúde pública, principalmente pelo conhecimento escasso de sua patogênese, e de estratégias terapêuticas e preventivas eficazes. Diversas lacunas de conhecimento sobre a doença envolvem a contribuição de fatores de risco, as doenças concomitantes, os fatores genéticos e imunogenéticos, no direcionamento da resposta imune, bem como a hiperinflamação, a imunidade antiviral e os alelos dos antígenos leucocitários humanos (HLAs) dos pacientes, que estão relacionados ao desfecho da doença. Objetivo: Esta revisão integrativa objetivou aprofundar os conhecimentos sobre os mecanismos de imunidade relacionada aos fatores de risco, da hiperinflamação e da tempestade de citocinas decorrente da infecção por SARS-CoV-2, bem como os avanços de associação dos HLAs nos agravos da doença. Metodologia: A revisão integrativa foi realizada utilizando os descritores nas bases de dados PubMed, SCIELO, CINAHL, SCOPUS, Web of Science, MedNar, Portal periódicos CAPES e Open Journal System, sem limites de janela cronológica. Resultados: Os efeitos da pandemia e os esforços na busca do conhecimento sobre a patogênese da COVID-19 resultaram em avanço no combate da doença. Conseguiu-se relacionar fatores de risco como obesidade, hipertensão, diabetes, doenças renais crônicas, idade, gênero, e outras condições predisponentes ao agravo da doença. Sob o aspecto da patogênese, também houveram progressos no entendimento dos mecanismos celulares e humorais em resposta à doença, bem como conseguiu vincular a resposta da hiperinflamação e o perfil dos HLAs dos pacientes à evolução da doença ao óbito ou à convalescência. Conclusão: Os esforços científicos conjuntos e os avanços na compreensão dos mecanismos da doença conseguiram estabelecer estratégias de combate a COVID-19, resultando no fim da pandemia, porém ainda há avanços que devem ser alcançados para o combate das sequelas dos pacientes convalescentes e para minimização da COVID longa e seus prejuízos.

Introduction: SARS-CoV-2, which causes the Coronavirus Disease 2019 (COVID-19) pandemic, has generated challenges to public health, mainly due to the limited knowledge of its pathogenesis and effective therapeutic and preventive strategies. Several gaps in knowledge about the disease involve the contribution of risk factors, concomitant diseases, genetic and immunogenetic factors, in directing the immune response, as well as hyperinflammation, antiviral immunity and human leukocyte antigen (HLAs) alleles of patients, which are related to the outcome of the disease. Aim: This integrative review aimed to deepen knowledge about the mechanisms of immunity related to risk factors, hyperinflammation and the cytokine storm resulting from SARS-CoV-2 infection, as well as advances in the association of HLAs in diseases. Methodology: The integrative review was carried out using the descriptors in the databases PubMed, SCIELO, CINAHL, SCOPUS, Web of Science, MedNar, CAPES periodical portal and Open Journal System, without chronological window limits. Results: The effects of the pandemic and efforts to seek knowledge about the pathogenesis of COVID-19 resulted in progress in combating the disease. It was possible to relate risk factors such as obesity, hypertension, diabetes, chronic kidney disease, age, gender, and other conditions predisposing to the worsening of the disease. From the aspect of pathogenesis, progress has also been made in understanding the cellular and humoral mechanisms in response to the disease, as well as linking the hyperinflammation response and the patients' HLA profile to the progression of the disease to death or convalescence. Conclusion: Joint scientific efforts and advances in understanding the mechanisms of the disease managed to establish strategies to combat COVID-19, resulting in the end of the pandemic, but there are still advances that must be achieved to combat the sequelae of convalescent patients and to minimize of long COVID and its losses.

Introducción: El SARS-CoV-2, causante de la pandemia de la Enfermedad del Coronavirus 2019 (COVID-19), ha generado desafíos a la salud pública, principalmente por el limitado conocimiento de su patogénesis y estrategias terapéuticas y preventivas efectivas. Varios vacíos en el conocimiento sobre la enfermedad involucran la contribución de factores de riesgo, enfermedades concomitantes, factores genéticos e inmunogenéticos, en la dirección de la respuesta inmune, así como la hiperinflamación, la inmunidad antiviral y los alelos del antígeno leucocitario humano (HLA) de los pacientes, que están relacionados con el resultado de la enfermedad. Objetivo: Esta revisión integradora tuvo como objetivo profundizar el conocimiento sobre los mecanismos de inmunidad relacionados con los factores de riesgo, la hiperinflamación y la tormenta de citocinas resultante de la infección por SARS-CoV-2, así como los avances en la asociación de los HLA en las complicaciones de la enfermedad. Metodología: La revisión integradora se realizó utilizando los descriptores de las bases de datos PubMed, SCIELO, CINAHL, SCOPUS, Web of Science, MedNar, portal periódico CAPES y Open Journal System, sin límites de ventana cronológica. Resultados: Los efectos de la pandemia y los esfuerzos por buscar conocimiento sobre la patogénesis de la COVID-19 resultaron en avances en el combate de la enfermedad. Se logró relacionar factores de riesgo como obesidad, hipertensión, diabetes, enfermedad renal crónica, edad, sexo y otras condiciones que predisponen al agravamiento de la enfermedad. Desde el punto de vista de la patogénesis, también se ha avanzado en la comprensión de los mecanismos celulares y humorales de respuesta a la enfermedad, así como en la vinculación de la respuesta de hiperinflamación y el perfil HLA de los pacientes con la progresión de la enfermedad hasta la muerte o la convalecencia. Conclusión: Los esfuerzos científicos conjuntos y los avances en la comprensión de los mecanismos de la enfermedad lograron establecer estrategias para combatir el COVID-19, teniendo como resultado el fin de la pandemia, pero aún quedan avances que se deben lograr para combatir las secuelas de los pacientes convalecientes y para Minimizar el COVID prolongado y sus pérdidas.

Inflammation, fibrosis and E1 glycoprotein persistence in joint tissue of patients with post-Chikungunya chronic articular disease

ABSTRACT Introduction: Chikungunya chronic joint disease causes debilitating arthralgia, significantly impacting the quality of life of affected individuals. Methods: In this study, patients underwent clinical follow-ups, joint biopsies, and pre-biopsy and 24 months post-biopsy serum dosage of cytokines. Results: All participants were female and had pain in 12 joints on average, with 41.17% exhibiting moderate disease activity. Histopathological analysis revealed collagen deposition. Indirect immunofluorescence detected the CHIKV glycoprotein E1 antigen, and an increase in cytokines. Conclusions: Persistent inflammation and ineffective antiviral immune responses leading to antigen persistence may contribute to chronic CHIKV arthritis.

Persistent SARS-CoV-2 antigen presence in multiple organs of a naturally infected cat from Brazil

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiological agent of the disease coronavirus 2019 (COVID-19) in humans. SARS-CoV-2 has been identified in cats with or without clinical signs. Case presentation: We describe the pathological and molecular findings in a six-month-old asymptomatic cat with SARS-CoV-2 infection from Brazil, belonging to a human family with COVID-19 cases. The pool of nasopharynx and oropharynx swabs at day zero tested positive by RT-qPCR for SARS-CoV-2. No amplification resulted from molecular testing performed on days 7 and 14. The cat was hit by a car and died 43 days after the molecular diagnosis. Immunohistochemistry at post-mortem examination demonstrated nucleocapsid protein in samples from the lungs, kidneys, nasal conchae, trachea, intestine, brain and spleen. Conclusion: The present study has highlighted the possibility that viral antigens can be detected by immunohistochemistry in multiple organs six weeks after infection, although the same tissues tested negative by RT-PCR.(AU)

Persistent SARS-CoV-2 antigen presence in multiple organs of a naturally infected cat from Brazil

Abstract Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiological agent of the disease coronavirus 2019 (COVID-19) in humans. SARS-CoV-2 has been identified in cats with or without clinical signs. Case presentation: We describe the pathological and molecular findings in a six-month-old asymptomatic cat with SARS-CoV-2 infection from Brazil, belonging to a human family with COVID-19 cases. The pool of nasopharynx and oropharynx swabs at day zero tested positive by RT-qPCR for SARS-CoV-2. No amplification resulted from molecular testing performed on days 7 and 14. The cat was hit by a car and died 43 days after the molecular diagnosis. Immunohistochemistry at post-mortem examination demonstrated nucleocapsid protein in samples from the lungs, kidneys, nasal conchae, trachea, intestine, brain and spleen. Conclusion: The present study has highlighted the possibility that viral antigens can be detected by immunohistochemistry in multiple organs six weeks after infection, although the same tissues tested negative by RT-PCR.

Influence of climatic variables on the Aedes aegypti and Culex quinquefasciatus populations in Mato Grosso, Brazil

Abstract INTRODUCTION: Aedes aegypti and Culex quinquefasciatus are vector species responsible for the transmission of important arboviruses. METHODS: Adult mosquitoes were collected in the urban areas of four municipalities in Mato Grosso within 1 year. RESULTS: A total of 19,110 mosquitoes were collected. Among them, 16,578 (86,8%) were C. quinquefasciatus (44% female and 56% male); 2,483 (13%), A. (Stegomyia) aegypti (54% female and 46% male); and 49 (0,30%), from the genus Psorophora, Anopheles, Coquilettidia, and Sabethes. A significant correlation was observed between the number of mosquitoes from all species and dew point (female mosquitoes, p = 0.001; male mosquitoes, p = 0.001). CONCLUSIONS: The results of this study may be used as environmental indicators of mosquito populations.

Seropositivity for Rickettsia spp. and Ehrlichia spp. in the human population of Mato Grosso, Central-Western Brazil

Abstract INTRODUCTION The epidemiology of Rickettsia and Ehrlichia species infection is underestimated in Mato Grosso State. METHODS: Serum samples obtained during a Dengue outbreak in 2011-2012 were tested via indirect immunofluorescence and/or ELISA. RESULTS: Samples from 19/506 (3.8%) patients presented antibodies for at least one of three Rickettsia species; 2/506 (0.4%) samples reacted against Ehrlichia canis. Most afflicted patients are residents of cities from the south-central region of the state, where these diseases have been reported in animals. CONCLUSIONS: These results show serological evidence of human exposure to Rickettsia and Ehrlichia species in Mato Grosso State.

Mayaro virus and dengue virus 1 and 4 natural infection in culicids from Cuiabá, state of Mato Grosso, Brazil

This study aimed to verify the diversity of Culicidae species and their frequency of infection with flaviviruses and alphaviruses in Cuiabá, state of Mato Grosso, Brazil. Mosquitoes were captured with Nasci aspirators and hand net in 200 census tracts, identified alive at species level and pooled in one-20 (11,090 mosquitoes, 14 species). Female pools (n = 610) were subjected to multiplex seminested-reverse transcription-polymerase chain reaction (RT-PCR) for 11 flavivirus and five alphavirus. Positive pools were tested by single RT-PCR followed by nucleotide sequencing, by RT-PCR for E1 gene [Mayaro virus (MAYV)] and by inoculation in Vero cells (MAYV) or C6/36 cells (flaviviruses). One/171 Aedes aegypti was positive for dengue virus (DENV)-1, 12/403 Culex quinquefasciatus, and four/171Ae. aegypti for MAYV, which was isolated from two pools containing two nonengorged females of Ae. aegypti and two ofCx. quinquefasciatus. DENV-4 was detected in 58/171 pools of Ae. aegytpi, 105/403 Cx. quinquefasciatus, two/five Psorophora sp., two/11 Psorophora varipes/Psorophora albigenu, one/one Sabethes chloropterus, two/five Culex bidens/Culex interfor, and one/one Aedes sp. DENV-4 was isolated from two pools containing three and 16 nonengorged Cx. quinquefasciatus females. Phylogenetic analysis revealed MAYV belongs to genotype L, clustering with human samples of the virus previously identified in the city. Cuiabá has biodiversity and ecosystem favourable for vector proliferation, representing a risk for arbovirus outbreaks.

Detection of Oropouche virus segment S in patients and inCulex quinquefasciatus in the state of Mato Grosso, Brazil

This study aimed to investigate the circulation of Orthobunyavirus species in the state of Mato Grosso (MT) Brazil. During a dengue outbreak in 2011/2012, 529 serum samples were collected from patients with acute febrile illness with symptoms for up to five days and 387 pools of female Culex quinquefasciatuscaptured in 2013 were subjected to nested-reverse transcription-polymerase chain reaction for segment S of the Simbu serogroup followed by nucleotide sequencing and virus isolation in Vero cells. Patients (5/529; 0.9%) from Cuiabá (n = 3), Várzea Grande (n = 1) and Nova Mutum (n = 1) municipalities were positive for the S segment of Oropouche virus (OROV). Additionally, eight/387 Cx. quinquefasciatuspools were positive for the segment, with a minimum infection rate of 2.3. Phylogenetic analysis indicated that all the samples belong to the subgenotype Ia, presenting high homology with OROV strains obtained from humans and animals in the Brazilian Amazon. The present paper reports the first detection of an Orthobunyavirus, possibly OROV, in patients and in Cx. quinquefasciatus mosquitoes in MT. This finding reinforces the notion that arboviruses frequently reported in the Amazon Region circulate sporadically in MT during dengue outbreaks.

Natural transovarial transmission of dengue virus 4 in Aedes aegypti from Cuiabá, State of Mato Grosso, Brazil

INTRODUCTION: Dengue is the most prevalent arboviral disease in tropical areas. In Mato Grosso, outbreaks are reported every year, but studies on dengue in this state are scarce. METHODS: Natural transovarial infection of Aedes aegypti by a flavivirus was investigated in the Jardim Industriário neighborhood of Cuiabá, Mato Grosso. Eggs were collected with ovitraps during the dry, intermediate, and rainy seasons of 2012. After the eggs hatched and the larvae developed to adulthood, mosquitoes (n = 758) were identified and allocated to pools of 1-10 specimens according to the collection location, sex, and climatic period. After RNA extraction, multiplex semi-nested RT-PCR was performed to detect the four dengue virus (DENV) serotypes, yellow fever virus, West Nile virus and Saint Louis encephalitis virus. RESULTS: DENV-4 was the only flavivirus detected, and it was found in 8/50 pools (16.0%). Three of the positive pools contained females, and five contained males. Their nucleotide sequences presented 96-100% similarity with DENV-4 genotype II strains from Manaus, Amazonas. The minimum infection rate was 10.5 per 1000 specimens, and the maximum likelihood estimator of the infection rate was 11.6 (95% confidence interval: 4.8; 23.3). CONCLUSIONS: This study provides the first evidence of natural transovarial infection by DENV-4 in Ae. Aegypti in Mato Grosso, suggesting that this type of infection might serve as a mechanism of virus maintenance during interepidemic periods in Cuiabá, a city where dengue epidemics are reported every year. These results emphasize the need for efficient vector population control measures to prevent arbovirus outbreaks in the state. .

Molecular detection of Mayaro virus during a dengue outbreak in the state of Mato Grosso, Central-West Brazil

Mayaro virus (MAYV) is frequently reported in Pan-Amazonia. The aim of this study was to investigate the circulation of alphaviruses during a dengue outbreak in the state of Mato Grosso, Brazil. Serum samples from dengue-suspected patients were subjected to multiplex semi-nested reverse transcriptase polymerase chain reaction for 11 flaviviruses and five alphaviruses, to nucleotide sequencing and to viral isolation. MAYV was detected in 15 (2.5%) of 604 patients. Twelve were co-infected with dengue virus 4, which was isolated from 10 patients. The molecular detection of MAYV in dengue-suspected patients suggests that other arboviruses may be silently circulating during dengue outbreaks in Brazil.