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Cytotoxic T lymphocytes (CTLs) mediate host defense against viral and intracellular bacterial infections and tumors. However, the magnitude of CTL response and their function needed to confer heterosubtypic immunity against influenza virus infection are unknown. We addressed the role of CD8+ T cells in the absence of any cross-reactive antibody responses to influenza viral proteins using an adenoviral vector expressing a 9mer amino acid sequence recognized by CD8+ T cells. Our results indicate that both CD8+ T cell frequency and function are crucial for heterosubtypic immunity. Low morbidity, lower viral lung titers, low to minimal lung pathology, and better survival upon heterosubtypic virus challenge correlated with the increased frequency of NP-specific CTLs. NP-CD8+ T cells induced by differential infection doses displayed distinct RNA transcriptome profiles and functional properties. CD8+ T cells induced by a high dose of influenza virus secreted significantly higher levels of IFN-γ and exhibited higher levels of cytotoxic function. The mice that received NP-CD8+ T cells from the high-dose virus recipients through adoptive transfer had lower viral titers following viral challenge than those induced by the low dose of virus, suggesting differential cellular programming by antigen dose. Enhanced NP-CD8+ T-cell functions induced by a higher dose of influenza virus strongly correlated with the increased expression of cellular and metabolic genes, indicating a shift to a more glycolytic metabolic phenotype. These findings have implications for developing effective T cell vaccines against infectious diseases and cancer. IMPORTANCE: Cytotoxic T lymphocytes (CTLs) are an important component of the adaptive immune system that clears virus-infected cells or tumor cells. Hence, developing next-generation vaccines that induce or recall CTL responses against cancer and infectious diseases is crucial. However, it is not clear if the frequency, function, or both are essential in conferring protection, as in the case of influenza. In this study, we demonstrate that both CTL frequency and function are crucial for providing heterosubtypic immunity to influenza by utilizing an Ad-viral vector expressing a CD8 epitope only to rule out the role of antibodies, single-cell RNA-seq analysis, as well as adoptive transfer experiments. Our findings have implications for developing T cell vaccines against infectious diseases and cancer.
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It is increasingly appreciated that pathogens can spread as infectious units constituted by multiple, genetically diverse genomes, also called collective infectious units or genome collectives. However, genetic characterization of the spatial dynamics of collective infectious units in animal hosts is demanding, and it is rarely feasible in humans. Measles virus (MeV), whose spread in lymphatic tissues and airway epithelia relies on collective infectious units, can, in rare cases, cause subacute sclerosing panencephalitis (SSPE), a lethal human brain disease. In different SSPE cases, MeV acquisition of brain tropism has been attributed to mutations affecting either the fusion or the matrix protein, or both, but the overarching mechanism driving brain adaptation is not understood. Here we analyzed MeV RNA from several spatially distinct brain regions of an individual who succumbed to SSPE. Surprisingly, we identified two major MeV genome subpopulations present at variable frequencies in all 15 brain specimens examined. Both genome types accumulated mutations like those shown to favor receptor-independent cell-cell spread in other SSPE cases. Most infected cells carried both genome types, suggesting the possibility of genetic complementation. We cannot definitively chart the history of the spread of this virus in the brain, but several observations suggest that mutant genomes generated in the frontal cortex moved outwards as a collective and diversified. During diversification, mutations affecting the cytoplasmic tails of both viral envelope proteins emerged and fluctuated in frequency across genetic backgrounds, suggesting convergent and potentially frequency-dependent evolution for modulation of fusogenicity. We propose that a collective infectious unit drove MeV pathogenesis in this brain. Re-examination of published data suggests that similar processes may have occurred in other SSPE cases. Our studies provide a primer for analyses of the evolution of collective infectious units of other pathogens that cause lethal disease in humans.
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Sarampo , Panencefalite Esclerosante Subaguda , Animais , Humanos , Panencefalite Esclerosante Subaguda/genética , Panencefalite Esclerosante Subaguda/patologia , Vírus do Sarampo/genética , Vírus do Sarampo/metabolismo , Sarampo/genética , Sarampo/metabolismo , Encéfalo/patologia , Tropismo/genéticaRESUMO
This review serves as an update to the previous Nocardia review by Brown-Elliott et al. published in 2006 (B. A. Brown-Elliott, J. M. Brown, P. S. Conville, and R. J. Wallace. Jr., Clin Microbiol Rev 19:259-282, 2006, https://doi.org/10.1128/CMR.19.2.259-282.2006). Included is a discussion on the taxonomic expansion of the genus, current identification methods, and the impact of new technology (including matrix-assisted laser desorption ionization-time of flight [MALDI-TOF] and whole genome sequencing) on diagnosis and treatment. Clinical manifestations, the epidemiology, and geographic distribution are briefly discussed. An additional section on actinomycotic mycetoma is added to address this often-neglected disease.
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Nocardia , Nocardia/genética , Técnicas de Tipagem Bacteriana , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
BACKGROUND: Lassa fever is a zoonotic, acute viral illness first identified in Nigeria in 1969. An estimate shows that the "at risk" seronegative population (in Sierra Leone, Guinea, and Nigeria) may be as high as 59 million, with an annual incidence of all illnesses of 3 million, and fatalities up to 67 000, demonstrating the serious impact of the disease on the region and global health. METHODS: Histopathologic evaluation, immunohistochemical assay, and electron microscopic examination were performed on postmortem tissue samples from 12 confirmed Lassa fever cases. RESULTS: Lassa fever virus antigens and viral particles were observed in multiple organ systems and cells, including cells in the mononuclear phagocytic system and other specialized cells where it had not been described previously. CONCLUSIONS: The immunolocalization of Lassa fever virus antigens in fatal cases provides novel insightful information with clinical and pathogenetic implications. The extensive involvement of the mononuclear phagocytic system, including tissue macrophages and endothelial cells, suggests participation of inflammatory mediators from this lineage with the resulting vascular dilatation and increasing permeability. Other findings indicate the pathogenesis of Lassa fever is multifactorial and additional studies are needed.
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Febre Lassa , Viroses , Células Endoteliais , Humanos , Incidência , Febre Lassa/epidemiologia , Vírus LassaRESUMO
BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic continues to produce substantial morbidity and mortality. To understand the reasons for the wide-spectrum complications and severe outcomes of COVID-19, we aimed to identify cellular targets of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) tropism and replication in various tissues. METHODS: We evaluated RNA extracted from formalin-fixed, paraffin-embedded autopsy tissues from 64 case patients (age range, 1 month to 84 years; 21 COVID-19 confirmed, 43 suspected COVID-19) by SARS-CoV-2 reverse-transcription polymerase chain reaction (RT-PCR). For cellular localization of SARS-CoV-2 RNA and viral characterization, we performed in situ hybridization (ISH), subgenomic RNA RT-PCR, and whole-genome sequencing. RESULTS: SARS-CoV-2 was identified by RT-PCR in 32 case patients (21 COVID-19 confirmed, 11 suspected). ISH was positive in 20 and subgenomic RNA RT-PCR was positive in 17 of 32 RT-PCR-positive case patients. SARS-CoV-2 RNA was localized by ISH in hyaline membranes, pneumocytes, and macrophages of lungs; epithelial cells of airways; and endothelial cells and vessel walls of brain stem, leptomeninges, lung, heart, liver, kidney, and pancreas. The D614G variant was detected in 9 RT-PCR-positive case patients. CONCLUSIONS: We identified cellular targets of SARS-CoV-2 tropism and replication in the lungs and airways and demonstrated its direct infection in vascular endothelium. This work provides important insights into COVID-19 pathogenesis and mechanisms of severe outcomes.
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COVID-19/virologia , Endotélio Vascular/virologia , Sistema Respiratório/virologia , SARS-CoV-2/fisiologia , Replicação Viral , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Autopsia , COVID-19/complicações , Teste de Ácido Nucleico para COVID-19 , Criança , Pré-Escolar , Feminino , Humanos , Hibridização In Situ , Lactente , Pulmão/virologia , Masculino , Pessoa de Meia-Idade , RNA Viral/isolamento & purificação , Reação em Cadeia da Polimerase em Tempo Real , SARS-CoV-2/genética , SARS-CoV-2/isolamento & purificação , Tropismo Viral , Sequenciamento Completo do Genoma , Adulto JovemRESUMO
BACKGROUND: Death in patients with chikungunya is rare and has been associated with encephalitis, hemorrhage, and septic shock. We describe clinical, histologic, and immunohistochemical findings in individuals who died following chikungunya virus (CHIKV) infection. METHODS: We identified individuals who died in Puerto Rico during 2014 following an acute illness and had CHIKV RNA detected by reverse transcriptase-polymerase chain reaction in a pre- or postmortem blood or tissue specimen. We performed histopathology and immunohistochemistry (IHC) for CHIKV antigen on tissue specimens and collected medical data via record review and family interviews. RESULTS: Thirty CHIKV-infected fatal cases were identified (0.8/100 000 population). The median age was 61 years (range: 6 days-86 years), and 19 (63%) were male. Death occurred a median of 4 days (range: 1-29) after illness onset. Nearly all (93%) had at least 1 comorbidity, most frequently hypertension, diabetes, or obesity. Nine had severe comorbidities (eg, chronic heart or kidney disease, sickle cell anemia) or coinfection (eg, leptospirosis). Among 24 fatal cases with tissue specimens, 11 (46%) were positive by IHC. CHIKV antigen was most frequently detected in mesenchymal tissues and mononuclear cells including tissue macrophages, blood mononuclear cells, splenic follicular dendritic cells, and Kupffer cells. Common histopathologic findings were intra-alveolar hemorrhage and edema in the lung, chronic or acute tenosynovitis, and increased immunoblasts in the spleen. CHIKV infection likely caused fatal septic shock in 2 patients. CONCLUSIONS: Evaluation of tissue specimens provided insights into the pathogenesis of CHIKV, which may rarely result in septic shock and other severe manifestations.
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Febre de Chikungunya , Vírus Chikungunya , Diabetes Mellitus , Febre de Chikungunya/complicações , Febre de Chikungunya/epidemiologia , Comorbidade , Humanos , Masculino , Pessoa de Meia-Idade , Porto RicoRESUMO
An ongoing pandemic of coronavirus disease (COVID-19) is caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Characterization of the histopathology and cellular localization of SARS-CoV-2 in the tissues of patients with fatal COVID-19 is critical to further understand its pathogenesis and transmission and for public health prevention measures. We report clinicopathologic, immunohistochemical, and electron microscopic findings in tissues from 8 fatal laboratory-confirmed cases of SARS-CoV-2 infection in the United States. All cases except 1 were in residents of long-term care facilities. In these patients, SARS-CoV-2 infected epithelium of the upper and lower airways with diffuse alveolar damage as the predominant pulmonary pathology. SARS-CoV-2 was detectable by immunohistochemistry and electron microscopy in conducting airways, pneumocytes, alveolar macrophages, and a hilar lymph node but was not identified in other extrapulmonary tissues. Respiratory viral co-infections were identified in 3 cases; 3 cases had evidence of bacterial co-infection.
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Betacoronavirus/patogenicidade , Infecções por Coronavirus/patologia , Pneumonia Viral/patologia , Idoso , COVID-19 , Infecções por Coronavirus/virologia , Feminino , Humanos , Imuno-Histoquímica , Pulmão/patologia , Pulmão/virologia , Masculino , Microscopia Eletrônica , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/virologia , SARS-CoV-2 , Estados Unidos/epidemiologiaRESUMO
The fifth wave of the H7N9 influenza epidemic in China was distinguished by a sudden increase in human infections, an extended geographic distribution, and the emergence of highly pathogenic avian influenza (HPAI) viruses. Genetically, some H7N9 viruses from the fifth wave have acquired novel amino acid changes at positions involved in mammalian adaptation, antigenicity, and hemagglutinin cleavability. Here, several human low-pathogenic avian influenza (LPAI) and HPAI H7N9 virus isolates from the fifth epidemic wave were assessed for their pathogenicity and transmissibility in mammalian models, as well as their ability to replicate in human airway epithelial cells. We found that an LPAI virus exhibited a similar capacity to replicate and cause disease in two animal species as viruses from previous waves. In contrast, HPAI H7N9 viruses possessed enhanced virulence, causing greater lethargy and mortality, with an extended tropism for brain tissues in both ferret and mouse models. These HPAI viruses also showed signs of adaptation to mammalian hosts by acquiring the ability to fuse at a lower pH threshold than other H7N9 viruses. All of the fifth-wave H7N9 viruses were able to transmit among cohoused ferrets but exhibited a limited capacity to transmit by respiratory droplets, and deep sequencing analysis revealed that the H7N9 viruses sampled after transmission showed a reduced amount of minor variants. Taken together, we conclude that the fifth-wave HPAI H7N9 viruses have gained the ability to cause enhanced disease in mammalian models and with further adaptation may acquire the ability to cause an H7N9 pandemic.IMPORTANCE The potential pandemic risk posed by avian influenza H7N9 viruses was heightened during the fifth epidemic wave in China due to the sudden increase in the number of human infections and the emergence of antigenically distinct LPAI and HPAI H7N9 viruses. In this study, a group of fifth-wave HPAI and LPAI viruses was evaluated for its ability to infect, cause disease, and transmit in small-animal models. The ability of HPAI H7N9 viruses to cause more severe disease and to replicate in brain tissues in animal models as well as their ability to fuse at a lower pH threshold than LPAI H7N9 viruses suggests that the fifth-wave H7N9 viruses have evolved to acquire novel traits with the potential to pose a higher risk to humans. Although the fifth-wave H7N9 viruses have not yet gained the ability to transmit efficiently by air, continuous surveillance and risk assessment remain essential parts of our pandemic preparedness efforts.
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Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Influenza Humana/virologia , Infecções por Orthomyxoviridae/epidemiologia , RNA Viral/genética , Análise de Sequência de RNA/métodos , Animais , Linhagem Celular , China/epidemiologia , Chlorocebus aethiops , Epidemias , Evolução Molecular , Furões , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Subtipo H7N9 do Vírus da Influenza A/genética , Influenza Humana/epidemiologia , Influenza Humana/transmissão , Camundongos , Infecções por Orthomyxoviridae/transmissão , Infecções por Orthomyxoviridae/virologia , Medição de Risco , Células Vero , Tropismo Viral , VirulênciaRESUMO
BACKGROUND: Recognition of rickettsialpox infection on skin biopsy can be challenging. The histopathology is non-specific and inconsistently described. We assess classic histopathologic features in confirmed cases and review the literature. METHODS: We searched for cases of "rickettsialpox" diagnosed between 2006 and 2018 with positive immunostaining for Spotted Fever Group Rickettsia species. Original slides were evaluated for vacuolar alterations, granulomatous inflammation, vasculitis, necrosis, fibrin thrombi, microvesiculation, papillary dermal edema, and extravasated red blood cells. All biopsies were stained for CD3, CD20, CD68, and myeloperoxidase. RESULTS: Six biopsy specimens were compiled, three of which were sampled from vesiculopapules, one from a maculopapule, and two from eschars. Vacuolar alterations and vasculitis were present in all specimens (6/6; 100%). Granulomatous inflammation was present in five specimens (5/6; 83.3%). Fibrin thrombi and red blood cells were seen in 3/6 (50%) of specimens. The eschars showed necrosis of the epidermis and superficial dermis (2/6, 33.3%). Only one specimen showed intraepidermal vesiculation and papillary dermal edema (1/6; 16.7%). All six specimens showed perivascular infiltration with CD3+ T-cells, and low amounts of CD20+ B-cells and neutrophils. Five of the six specimens (83.3%) showed significant levels of CD68+ histiocytes. CONCLUSION: The histopathology of rickettsialpox infection is septic lymphocytic and granulomatous vasculitis.
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Infecções por HIV/complicações , Imuno-Histoquímica/métodos , Rickettsia akari/imunologia , Rickettsiose do Grupo da Febre Maculosa/metabolismo , Rickettsiose do Grupo da Febre Maculosa/patologia , Adulto , Idoso de 80 Anos ou mais , Antígenos CD/metabolismo , Antígenos CD20/metabolismo , Antígenos de Diferenciação Mielomonocítica/metabolismo , Biópsia/métodos , Complexo CD3/metabolismo , Feminino , HIV/isolamento & purificação , Infecções por HIV/diagnóstico , Infecções por HIV/patologia , Histiócitos/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Necrose/etiologia , Necrose/patologia , Peroxidase/metabolismo , Rickettsia akari/isolamento & purificação , Pele/patologia , Dermatopatias/microbiologia , Dermatopatias/patologia , Rickettsiose do Grupo da Febre Maculosa/microbiologia , Vasculite/etiologia , Vasculite/patologiaRESUMO
This manuscript describes the Child Health and Mortality Prevention Surveillance (CHAMPS) network approach to pathologic evaluation of minimally invasive tissue sampling (MITS) specimens, including guidelines for histopathologic examination and further diagnostics with special stains, immunohistochemistry, and molecular testing, as performed at the CHAMPS Central Pathology Laboratory (CPL) at the Centers for Disease Control and Prevention, as well as techniques for virtual discussion of these cases (telepathology) with CHAMPS surveillance locations. Based on review of MITS from the early phase of CHAMPS, the CPL has developed standardized histopathology-based algorithms for achieving diagnoses from MITS and telepathology procedures in conjunction with the CHAMPS sites, with the use of whole slide scanners and digital image archives, for maximizing concurrence and knowledge sharing between site and CPL pathologists. These algorithms and procedures, along with lessons learned from initial implementation of these approaches, guide pathologists at the CPL and CHAMPS sites through standardized diagnostics of MITS cases, and allow for productive, real-time case discussions and consultations.
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Vigilância da População/métodos , Manejo de Espécimes/métodos , Telepatologia/métodos , Criança , Saúde da Criança , Mortalidade da Criança , HumanosRESUMO
BACKGROUND: In fall 2017, 3 solid organ transplant (SOT) recipients from a common donor developed encephalitis within 1 week of transplantation, prompting suspicion of transplant-transmitted infection. Eastern equine encephalitis virus (EEEV) infection was identified during testing of endomyocardial tissue from the heart recipient. METHODS: We reviewed medical records of the organ donor and transplant recipients and tested serum, whole blood, cerebrospinal fluid, and tissue from the donor and recipients for evidence of EEEV infection by multiple assays. We investigated blood transfusion as a possible source of organ donor infection by testing remaining components and serum specimens from blood donors. We reviewed data from the pretransplant organ donor evaluation and local EEEV surveillance. RESULTS: We found laboratory evidence of recent EEEV infection in all organ recipients and the common donor. Serum collected from the organ donor upon hospital admission tested negative, but subsequent samples obtained prior to organ recovery were positive for EEEV RNA. There was no evidence of EEEV infection among donors of the 8 blood products transfused into the organ donor or in products derived from these donations. Veterinary and mosquito surveillance showed recent EEEV activity in counties nearby the organ donor's county of residence. Neuroinvasive EEEV infection directly contributed to the death of 1 organ recipient and likely contributed to death in another. CONCLUSIONS: Our investigation demonstrated EEEV transmission through SOT. Mosquito-borne transmission of EEEV to the organ donor was the likely source of infection. Clinicians should be aware of EEEV as a cause of transplant-associated encephalitis.
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Encefalomielite Equina/transmissão , Doadores de Tecidos , Transplantados/estatística & dados numéricos , Transplante/efeitos adversos , Adulto , Animais , Culicidae/virologia , Vírus da Encefalite Equina do Leste , Encefalomielite Equina/sangue , Evolução Fatal , Feminino , Transplante de Coração/efeitos adversos , Humanos , Transplante de Fígado/efeitos adversos , Transplante de Pulmão/efeitos adversos , Prontuários Médicos , Pessoa de Meia-IdadeAssuntos
Colecistite/etiologia , Dengue/diagnóstico , Adulto , Colecistite/diagnóstico , Colecistite/cirurgia , Doenças Transmissíveis Importadas , Cuba , Dengue/complicações , Dengue/epidemiologia , Vírus da Dengue/genética , Evolução Fatal , Feminino , Florida/epidemiologia , Honduras , Humanos , Testes de Função Hepática , RNA Viral/sangue , ViagemRESUMO
Postmortem examination results of a patient with Guillain-Barré syndrome and confirmed Zika virus infection revealed demyelination of the sciatic and cranial IV nerves, providing evidence of the acute demyelinating inflammatory polyneuropathy Guillain-Barré syndrome variant. Lack of evidence of Zika virus in nervous tissue suggests that pathophysiology was antibody mediated without neurotropism.
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Autopsia , Coinfecção/virologia , Síndrome de Guillain-Barré/complicações , Infecção por Zika virus/complicações , Idoso , Coinfecção/patologia , Síndrome de Guillain-Barré/patologia , Síndrome de Guillain-Barré/virologia , Humanos , Masculino , Porto Rico , Infecção por Zika virus/patologia , Infecção por Zika virus/virologiaRESUMO
Here we describe clinicopathologic features of Ebola virus disease in pregnancy. One woman infected with Sudan virus in Gulu, Uganda, in 2000 had a stillbirth and survived, and another woman infected with Bundibugyo virus had a live birth with maternal and infant death in Isiro, the Democratic Republic of the Congo in 2012. Ebolavirus antigen was seen in the syncytiotrophoblast and placental maternal mononuclear cells by immunohistochemical analysis, and no antigen was seen in fetal placental stromal cells or fetal organs. In the Gulu case, ebolavirus antigen localized to malarial parasite pigment-laden macrophages. These data suggest that trophoblast infection may be a mechanism of transplacental ebolavirus transmission.
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Ebolavirus/isolamento & purificação , Doença pelo Vírus Ebola/patologia , Doença pelo Vírus Ebola/virologia , Complicações Infecciosas na Gravidez/patologia , Complicações Infecciosas na Gravidez/virologia , Adulto , Anticorpos Antivirais/sangue , Antígenos Virais/imunologia , Antígenos Virais/isolamento & purificação , República Democrática do Congo , Ebolavirus/química , Ebolavirus/genética , Ebolavirus/imunologia , Feminino , Doença pelo Vírus Ebola/imunologia , Doença pelo Vírus Ebola/transmissão , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Imuno-Histoquímica , Macrófagos/parasitologia , Macrófagos/ultraestrutura , Macrófagos/virologia , Malária/complicações , Malária/imunologia , Malária/virologia , Microscopia Eletrônica de Transmissão , Placenta/ultraestrutura , Placenta/virologia , Reação em Cadeia da Polimerase , Gravidez , Complicações Infecciosas na Gravidez/imunologia , Complicações Infecciosas na Gravidez/parasitologia , Natimorto , Células Estromais/ultraestrutura , Células Estromais/virologia , Trofoblastos/parasitologia , Trofoblastos/ultraestrutura , Trofoblastos/virologiaRESUMO
We describe an investigation into a Heartland virus (HRTV)-associated death in Tennessee with novel clinical and pathologic findings. HRTV can cause rapidly fatal, widely disseminated infection with multisystem organ failure in patients without substantial comorbidities. We identified viral antigen in multiple organ tissues where it was not detected previously.
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Infecções por Bunyaviridae/diagnóstico , Infecções por Bunyaviridae/patologia , Insuficiência de Múltiplos Órgãos/etiologia , Insuficiência de Múltiplos Órgãos/patologia , Phlebovirus/isolamento & purificação , Idoso , Antígenos Virais/análise , Encéfalo/patologia , Encéfalo/virologia , Infecções por Bunyaviridae/complicações , Infecções por Bunyaviridae/virologia , Evolução Fatal , Coração/virologia , Histocitoquímica , Humanos , Imuno-Histoquímica , Fígado/patologia , Fígado/virologia , Masculino , Microscopia , Miocárdio/patologia , Phlebovirus/classificação , Tennessee , Testículo/patologia , Testículo/virologiaRESUMO
Zika virus is causally linked with congenital microcephaly and may be associated with pregnancy loss. However, the mechanisms of Zika virus intrauterine transmission and replication and its tropism and persistence in tissues are poorly understood. We tested tissues from 52 case-patients: 8 infants with microcephaly who died and 44 women suspected of being infected with Zika virus during pregnancy. By reverse transcription PCR, tissues from 32 (62%) case-patients (brains from 8 infants with microcephaly and placental/fetal tissues from 24 women) were positive for Zika virus. In situ hybridization localized replicative Zika virus RNA in brains of 7 infants and in placentas of 9 women who had pregnancy losses during the first or second trimester. These findings demonstrate that Zika virus replicates and persists in fetal brains and placentas, providing direct evidence of its association with microcephaly. Tissue-based reverse transcription PCR extends the time frame of Zika virus detection in congenital and pregnancy-associated infections.
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Aborto Espontâneo , Encéfalo/virologia , Placenta/virologia , RNA Viral/isolamento & purificação , Replicação Viral/fisiologia , Infecção por Zika virus/virologia , Zika virus/isolamento & purificação , Adolescente , Adulto , Feminino , Feto/virologia , Humanos , Lactente , Transmissão Vertical de Doenças Infecciosas , Microcefalia , Gravidez , Complicações Infecciosas na Gravidez/virologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Adulto JovemRESUMO
BACKGROUND: Zika virus is an arthropod-borne virus that is a member of the family Flaviviridae transmitted mainly by mosquitoes of the genus Aedes. Although usually asymptomatic, infection can result in a mild and self-limiting illness characterised by fever, rash, arthralgia, and conjunctivitis. An increase in the number of children born with microcephaly was noted in 2015 in regions of Brazil with high transmission of Zika virus. More recently, evidence has been accumulating supporting a link between Zika virus and microcephaly. Here, we describe findings from three fatal cases and two spontaneous abortions associated with Zika virus infection. METHODS: In this case series, formalin-fixed paraffin-embedded tissue samples from five cases, including two newborn babies with microcephaly and severe arthrogryposis who died shortly after birth, one 2-month-old baby, and two placentas from spontaneous abortions, from Brazil were submitted to the Infectious Diseases Pathology Branch at the US Centers for Disease Control and Prevention (Atlanta, GA, USA) between December, 2015, and March, 2016. Specimens were assessed by histopathological examination, immunohistochemical assays using a mouse anti-Zika virus antibody, and RT-PCR assays targeting the NS5 and envelope genes. Amplicons of RT-PCR positive cases were sequenced for characterisation of strains. FINDINGS: Viral antigens were localised to glial cells and neurons and associated with microcalcifications in all three fatal cases with microcephaly. Antigens were also seen in chorionic villi of one of the first trimester placentas. Tissues from all five cases were positive for Zika virus RNA by RT-PCR, and sequence analyses showed highest identities with Zika virus strains isolated from Brazil during 2015. INTERPRETATION: These findings provide strong evidence of a link between Zika virus infection and different congenital central nervous system malformations, including microcephaly as well as arthrogryposis and spontaneous abortions. FUNDING: None.
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Encéfalo/patologia , Encéfalo/virologia , Deformidades Congênitas dos Membros/virologia , Microcefalia/virologia , Complicações Infecciosas na Gravidez/patologia , Complicações Infecciosas na Gravidez/virologia , Primeiro Trimestre da Gravidez , Infecção por Zika virus/congênito , Infecção por Zika virus/patologia , Zika virus/isolamento & purificação , Aborto Espontâneo/virologia , Adulto , Antígenos Virais/isolamento & purificação , Autopsia , Brasil , Evolução Fatal , Feminino , Humanos , Imuno-Histoquímica/métodos , Lactente , Deformidades Congênitas dos Membros/diagnóstico por imagem , Masculino , Microcefalia/patologia , Neuroglia/patologia , Neuroglia/virologia , Placenta/patologia , Placenta/virologia , Gravidez , Segundo Trimestre da Gravidez , Terceiro Trimestre da Gravidez , RNA Viral/isolamento & purificação , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Síndrome , Ultrassonografia Pré-Natal , Zika virus/imunologiaRESUMO
UNLABELLED: Three waves of human infection with H7N9 influenza viruses have concluded to date, but only viruses within the first wave (isolated between March and September 2013) have been extensively studied in mammalian models. While second- and third-wave viruses remain closely linked phylogenetically and antigenically, even subtle molecular changes can impart critical shifts in mammalian virulence. To determine if H7N9 viruses isolated from humans during 2013 to 2015 have maintained the phenotype first identified among 2013 isolates, we assessed the ability of first-, second-, and third-wave H7N9 viruses isolated from humans to cause disease in mice and ferrets and to transmit among ferrets. Similar to first-wave viruses, H7N9 viruses from 2013 to 2015 were highly infectious in mice, with lethality comparable to that of the well-studied A/Anhui/1/2013 virus. Second- and third-wave viruses caused moderate disease in ferrets, transmitted efficiently to cohoused, naive contact animals, and demonstrated limited transmissibility by respiratory droplets. All H7N9 viruses replicated efficiently in human bronchial epithelial cells, with subtle changes in pH fusion threshold identified between H7N9 viruses examined. Our results indicate that despite increased genetic diversity and geographical distribution since their initial detection in 2013, H7N9 viruses have maintained a pathogenic phenotype in mammals and continue to represent an immediate threat to public health. IMPORTANCE: H7N9 influenza viruses, first isolated in 2013, continue to cause human infection and represent an ongoing public health threat. Now entering the fourth wave of human infection, H7N9 viruses continue to exhibit genetic diversity in avian hosts, necessitating continuous efforts to monitor their pandemic potential. However, viruses isolated post-2013 have not been extensively studied, limiting our understanding of potential changes in virus-host adaptation. In order to ensure that current research with first-wave H7N9 viruses still pertains to more recently isolated strains, we compared the relative virulence and transmissibility of H7N9 viruses isolated during the second and third waves, through 2015, in the mouse and ferret models. Our finding that second- and third-wave viruses generally exhibit disease in mammals comparable to that of first-wave viruses strengthens our ability to extrapolate research from the 2013 viruses to current public health efforts. These data further contribute to our understanding of molecular determinants of pathogenicity, transmissibility, and tropism.
Assuntos
Subtipo H7N9 do Vírus da Influenza A/fisiologia , Infecções por Orthomyxoviridae/transmissão , Infecções por Orthomyxoviridae/virologia , Substituição de Aminoácidos , Animais , Linhagem Celular , Modelos Animais de Doenças , Células Epiteliais/virologia , Feminino , Furões , Variação Genética , Genoma Viral , Genótipo , Humanos , Influenza Humana/transmissão , Influenza Humana/virologia , Masculino , Camundongos , Infecções por Orthomyxoviridae/patologia , Mucosa Respiratória/patologia , Mucosa Respiratória/virologia , Carga Viral , Proteínas Virais/genética , Replicação ViralRESUMO
Avian influenza A H7 viruses have caused multiple outbreaks in domestic poultry throughout North America, resulting in occasional infections of humans in close contact with affected birds. In early 2016, the presence of H7N8 highly pathogenic avian influenza (HPAI) viruses and closely related H7N8 low-pathogenic avian influenza (LPAI) viruses was confirmed in commercial turkey farms in Indiana. These H7N8 viruses represent the first isolation of this subtype in domestic poultry in North America, and their virulence in mammalian hosts and the potential risk for human infection are largely unknown. In this study, we assessed the ability of H7N8 HPAI and LPAI viruses to replicate in vitro in human airway cells and in vivo in mouse and ferret models. Both H7N8 viruses replicated efficiently in vitro and in vivo, but they exhibited substantial differences in disease severity in mammals. In mice, while the H7N8 LPAI virus largely remained avirulent, the H7N8 HPAI virus exhibited greater infectivity, virulence, and lethality. Both H7N8 viruses replicated similarly in ferrets, but only the H7N8 HPAI virus caused moderate weight loss, lethargy, and mortality. The H7N8 LPAI virus displayed limited transmissibility in ferrets placed in direct contact with an inoculated animal, while no transmission of H7N8 HPAI virus was detected. Our results indicate that the H7N8 avian influenza viruses from Indiana are able to replicate in mammals and cause severe disease but with limited transmission. The recent appearance of H7N8 viruses in domestic poultry highlights the need for continued influenza surveillance in wild birds and close monitoring of the potential risk to human health. IMPORTANCE: H7 influenza viruses circulate in wild birds in the United States, but when the virus emerges in domestic poultry populations, the frequency of human exposure and the potential for human infections increases. An H7N8 highly pathogenic avian influenza (HPAI) virus and an H7N8 low-pathogenic avian influenza (LPAI) virus were recently isolated from commercial turkey farms in Indiana. To determine the risk that these influenza viruses pose to humans, we assessed their pathogenesis and transmission in vitro and in mammalian models. We found that the H7N8 HPAI virus exhibited enhanced virulence, and although transmission was only observed with the H7N8 LPAI virus, the ability of this H7 virus to transmit in a mammalian host and quickly evolve to a more virulent strain is cause for concern. Our findings offer important insight into the potential for emerging H7 avian influenza viruses to acquire the ability to cause disease and transmit among mammals.
Assuntos
Vírus da Influenza A/patogenicidade , Influenza Aviária/virologia , Doenças das Aves Domésticas/virologia , Perus/virologia , Animais , Animais Selvagens/virologia , Linhagem Celular , Modelos Animais de Doenças , Surtos de Doenças/veterinária , Furões , Especificidade de Hospedeiro , Humanos , Indiana/epidemiologia , Vírus da Influenza A/classificação , Vírus da Influenza A/isolamento & purificação , Influenza Aviária/epidemiologia , Influenza Aviária/transmissão , Influenza Humana/transmissão , Influenza Humana/virologia , Pulmão/patologia , Pulmão/virologia , Camundongos , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/transmissão , Virulência , Replicação ViralRESUMO
Fatal Lyme carditis caused by the spirochete Borrelia burgdorferi rarely is identified. Here, we describe the pathologic, immunohistochemical, and molecular findings of five case patients. These sudden cardiac deaths associated with Lyme carditis occurred from late summer to fall, ages ranged from young adult to late 40s, and four patients were men. Autopsy tissue samples were evaluated by light microscopy, Warthin-Starry stain, immunohistochemistry, and PCR for B. burgdorferi, and immunohistochemistry for complement components C4d and C9, CD3, CD79a, and decorin. Post-mortem blood was tested by serology. Interstitial lymphocytic pancarditis in a relatively characteristic road map distribution was present in all cases. Cardiomyocyte necrosis was minimal, T cells outnumbered B cells, plasma cells were prominent, and mild fibrosis was present. Spirochetes in the cardiac interstitium associated with collagen fibers and co-localized with decorin. Rare spirochetes were seen in the leptomeninges of two cases by immunohistochemistry. Spirochetes were not seen in other organs examined, and joint tissue was not available for evaluation. Although rare, sudden cardiac death caused by Lyme disease might be an under-recognized entity and is characterized by pancarditis and marked tropism of spirochetes for cardiac tissues.