Development of a prototype immunochromatographic test for rapid diagnosis of respiratory adenovirus infection

Abstract Human adenoviruses comprise an important group of etiologic agents that are responsible for various diseases in adults and children, such as respiratory, ocular, gastroenteric, and urinary infections. In immunocompromised and organ-transplanted individuals, these agents can cause generalized infections. Rapid diagnostic methods for detecting these infectious agents are not widely available.The aim of this work was to produce monoclonal and polyclonal anti-adenovirus antibodies to be used in a rapid diagnostic test for respiratory infections.Adenovirus hexons were satisfactorily purified by ultracentrifugation and chromatography. After virus purification, anti-hexon monoclonal antibodies were produced and characterized, following classical methods. Antibodies were specific for adenoviruses 2, 3, 5, and 41. The proposed immunochromatographic test was standardized using colloidal gold.The standardization of the rapid test was sufficient to detect adenovirus antigens (in nasopharyngeal lavage samples) with sensitivity of 100% and specificity of 85% when compared to direct immunofluorescence.The immunochromatographic assay prototype was sufficiently sensitive to detect B (3), C (2 and 5), and F (41) adenovirus samples. Although based on preliminary data, the test demonstrated the same performance as direct immunofluorescence, but with the advantage of being a point-of-care test. Further studies are still needed to confirm its effectiveness in clinical practice.

The role of human adenoviruses type 41 in acute diarrheal disease in Minas Gerais after rotavirus vaccination

Abstract Human adenovirus species F (HAdV-F) type 40 and 41 are commonly associated with acute diarrheal disease (ADD) across the world. Despite being the largest state in southeastern Brazil and having the second largest number of inhabitants, there is no information in the State of Minas Gerais regarding the role of HAdV-F in the etiology of ADD. This study was performed to determine the prevalence, to verify the epidemiological aspects of infection, and to characterize the strains of human adenoviruses (HAdV) detected. A total of 377 diarrheal fecal samples were obtained between January 2007 and August 2011 from inpatient and outpatient children of age ranging from 0 to 12 years. All samples were previously tested for rotavirus, norovirus, and astrovirus, and 314 of 377 were negative. The viral DNA was extracted, amplified using the polymerase chain reaction and the HAdV-positive samples were sequenced and phylogenetically analyzed. Statistical analyses were performed using the Chi-square test (p < 0.05), considering two conditions: the total of samples tested (377) and the total of negative samples for the remaining viruses tested (314). The overall prevalence of HAdV was 12.47% (47/377); and in 76.60% (36/47) of the positive samples, this virus was the only infectious agent detected. The phylogenetic analysis of partial sequences of 32 positive samples revealed that they all clustered with the HAdV-F type 41. The statistical analysis showed that there was no correlation between the onset of the HAdV infection and the origin of the samples (inpatients or outpatients) in the two conditions tested: the total of samples tested (p = 0.598) and the total of negative samples for the remaining viruses tested (p = 0.614). There was a significant association in the occurrence of infection in children aged 0–12 months for the condition 1 (p = 0.030) as well as condition 2 (p = 0.019). The occurrence of infections due to HAdV did not coincide with a pattern of seasonal distribution. These data indicate the significant involvement of HAdV-F type 41 in the etiology of ADD in Minas Gerais, which demonstrates the importance of other viral agents in the development of the disease after the introduction of rotavirus vaccine immunization.

Seasonal variation on the presence of adenoviruses in stools from non-diarrheic patients

Human adenoviruses (HAdV), members of the Adenoviridae family, are excreted through the fecal route and may be present in the feces of humans consuming contaminated food or water. The presence of HAdV from different serotypes in the feces of healthy individuals was already reported using conventional polymerase chain reaction; however, real-time PCR (qPCR) may reveal not only the rates of detection as well as demonstrate the viral loads excreted by healthy persons. Aiming to identify and characterize the presence of adenoviruses in stool samples, 147 fecal samples from patients with no records of diarrhea were analyzed (74 from winter season and 73 from summer) by Real-Time PCR (qPCR) assay and conventional PCR. HAdV genome was present in 43.8% (32/73) of stools samples collected during summer season and 21.6% (16/74) during winter. The rate of detection of genomic copies (gc) ranged from 4.04×10² to 6.72×10⁵gc/g of feces among the 147 samples analyzed, of which the ranged of genomic copies of DNA HAdV was major in summer. All samples were negative when tested for rotaviruses (RV) and noroviruses (NoV) by PCR conventional and qPCR respectively. HAdV is excreted constantly by infected individuals in the absence of clinical signs and the occurrence may vary seasonally.

Adeno-associated virus for cystic fibrosis gene therapy

Gene therapy is an alternative treatment for genetic lung disease, especially monogenic disorders such as cystic fibrosis. Cystic fibrosis is a severe autosomal recessive disease affecting one in 2500 live births in the white population, caused by mutation of the cystic fibrosis transmembrane conductance regulator (CFTR). The disease is classically characterized by pancreatic enzyme insufficiency, an increased concentration of chloride in sweat, and varying severity of chronic obstructive lung disease. Currently, the greatest challenge for gene therapy is finding an ideal vector to deliver the transgene (CFTR) to the affected organ (lung). Adeno-associated virus is the most promising viral vector system for the treatment of respiratory disease because it has natural tropism for airway epithelial cells and does not cause any human disease. This review focuses on the basic properties of adeno-associated virus and its use as a vector for cystic fibrosis gene therapy.

Infection kinetics of human adenovirus serotype 41 in HEK 293 cells

The purpose of this work was to acquire an overview of the infectious cycle of HAdV-41 in permissive HEK 293 cells and compare it to that observed with the prototype of the genus, Human adenovirus C HAdV-2. HEK 293 cells were infected with each virus separately and were harvested every 12 h for seven days. Infection kinetics were analysed using confocal and electronic microscopy. The results show that, when properly cultivated, HAdV-41 was not fastidious. It had a longer multiplication cycle, which resulted in the release of complete viral particles and viral stocks reached high titres. After 60 h of infection, the export of viral proteins from the infected cell to the extracellular milieu was observed, with a pattern similar to that previously described for HAdV-2 penton-base trafficking after 30 h of infection. HAdV-41 had a non-lytic cycle and the infection spread from the first infected cell to its neighbours. The release process of the viral particles is unknown. The results observed for HAdV-41 infection in HEK 293 cells show how different this virus is from the prototype HAdV-2 and provides information for the development of this vector for use in gene therapy.

Molecular epidemiology of adenovirus conjunctivitis in Rio de Janeiro, Brazil, between 2004 and 2007 / Epidemiologia molecular de adenovírus associados à conjuntivite no Rio de Janeiro, Brasil, no periodo de 2004 a 2007

Viral conjunctivitis is a common, highly contagious disease often caused by adenovirus. We investigate the frequency of adenoviral conjunctivitis in the population of Rio de Janeiro, Brazil, between March 2004 and May 2007 and identified the predominant serotype circulating among this population. Seventy-five ocular swabs were collected from 66 patients with clinical presentation of conjunctivitis. The specimens were analyzed for detection of adenovirus (AdV) by polymerase chain reaction (PCR). The PCR products were further analyzed for virus typing by sequence analysis and/or heteroduplex mobility assay (HMA). Forty-five samples (60%) were positive for AdV of which 21 samples were typed as AdV19 (46.7%), 7 AdV8 (15.5%), 3 AdV31 (6.7%), and one each AdV1, AdV2, AdV3, AdV4 and AdV6. For nine samples the serotype was not determined. AdV19 was the predominant serotype circulating in Rio de Janeiro during the studied period.

A conjuntivite viral é doença ocular comum, altamente contagiosa, frequentemente causada por adenovírus. Neste estudo, investigamos a frequência de conjuntivite por adenovírus na população do Rio de Janeiro, Brasil, entre março de 2004 e maio de 2007, e identificamos o sorotipo predominante circulando nesta população. Setenta e cinco swabs de secreção ocular foram coletados de 66 pacientes com conjuntivite. As amostras foram analisadas para detecção de adenovírus (AdV) por reação em cadeia da polimerase (PCR). Os produtos da PCR foram caracterizados por sequenciamento e/ou ensaio de mobilidade do heteroduplex (Heteroduplex Mobility Assay - HMA) para identificação do sorotipo viral. Quarenta e cinco (60%) amostras foram positivas para AdV das quais 21 foram identificadas como pertencentes ao sorotipo AdV19 (46,7%), sete AdV8 (15,5%), três AdV31 (6,7%), e uma de cada: AdV1, AdV2, AdV3, AdV4 e AdV6. Para nove amostras o sorotipo não pode ser identificado. O AdV 19 foi o sorotipo predominante circulando no Rio de Janeiro durante o período estudado.

Infeccions as the etiology for obesity / Infecções na etiologia da obesidade

The role of infection on obesity development has been questioned since the early 1980's. Several studies on animals have shown that fisiopathologic mechanisms through which infections can produce obesity do exist. At least eight types of obesity-inducing viruses have been identified in animals, especially poultry and mice. Studies on humans are far less convincing; however, two adenoviruses, Ad-36 and SMAM-1, have shown adipogenic properties. In vitro studies with 3T3-L1 cells stated the activation of the enzymatic pathway that leads to fatty tissue accumulation; in vivo studies have also detected higher levels of antibodies against such viruses on obese subjects. Although most known infections nowadays cause obesity through central nervous system lesions, the Ad-36 adenovirus infection affects fatty tissue directly, raising doubts regarding central role component in this case.

Desde o início dos anos 1980, o papel das infecções tem sido debatido quanto à etiologia da obesidade. Diversos estudos em modelos animais têm demonstrado que mecanismos fisiopatológicos ativados pelas infecções podem induzir também à obesidade. Pelo menos oito tipos de obesidade induzidas por viroses foram caracterizadas em animais, especialmente em camundongos e galinhas. Estudos em humanos existem, mas são menos convincentes. No entanto, duas adenoviroses (Ad-36 e SMAN-1) apresentam características adipogênicas. Estudos in vitro com a linhagem celular 3T3-L1 demonstraram que ativações enzimáticas levam ao acúmulo de gordura celular. Estudos in vivo detectaram níveis elevados de anticorpos contra certas viroses especialmente em indivíduos obesos. A maioria das infecções potenciais causadoras de obesidade atua produzindo ativações ou lesões no sistema nervoso central. Por outro lado, a infecção por Ad-36 adenovírus afeta diretamente o tecido adiposo, expandindo dessa forma a etiologia viral da obesidade para mecanismos hipotalâmicos e periféricos.

Infecções respiratórias agudas virais em crianças de Salvador: análise antigênica e genômica dos virus sincicial respiratório e adenovirus isolados com correlação clínica / Viral acute respiratory infections in childrens from Salvador: antigenic and genomics analysis of isolates of respiratory syncytial virus and adenovirus with clinic correlation

O presente estudo foi desenvolvido com o objetivo de contribuir para o conhecimento da prevalência viral em casos de infecções respiratórias agudas (IRA) em crianças de Salvador, assim como realizar a caracterização antigênica e genômica dos adenovírus e vírus sincicial respiratório (VSR) isolados. Um total de 482 casos de infecção respiratória aguda do ano de 1998 foram investigados quanto a etiologia viral através de imunofluorescência indireta e isolamento em cultura celular. Trinta adenovírus isolados em 1998, 1997 e 1996 foram submetidos soroneutralização e análise de restrição enzimática. Imunofluorescência indireta e ELISA foram utilizados para caracterização antigênica de VSR detectados em 1998 e 1999, respectivamente. A caracterização genômica de VSR foi realizada através da amplificação do gene da proteína G e posterior seqüenciamento de nucleotídeos. Cento e cinquenta e quatro casos de infecção respiratória aguda tiveram sua etiologia viral diagnosticada. Os vírus mais prevalentes em ordem decrescente foram o VSR, influenza A, parainfluenza 3, adenovírus, influenza B e parainfluenza 1. As IRA virais acometeram principalmente crianças até um ano de idade, do sexo masculino, e foram diagnosticadas predominantemente como infecção de vias aéreas superiores. Dos 30 Adenovírus analisados, dezoito eram Ad2, seis Adl, cinco Ad3 e um Ad5. A caracterização genômica dos Ad2 mostrou que circularam o genotipo D5 e uma nova variante genômica. Entre os Ad 1, circularam o genotipo DI e duas novas variantes genômicas. Representantes dos Ad3 e Ad5 foram os tipos genômicos 3f e 5#, respectivamente. Entre 84 VSR detectados em 1998,64 pertenciam ao grupo A e 14 ao grupo B. A análise genômica de 6 cepas de VSR mostrou a existência de vários genótipos circulantes em 1999. O VSR foi o vírus mais prevalente entre sete vírus investigados. Durante o mesmo período epidêmico houve a circulação de ambos...