Molecular characterization of adenoviruses from children presenting with acute respiratory disease in Uberlândia, Minas Gerais, Brazil, and detection of an isolate genetically related to feline adenovirus

Serotype Identification of Human Adenoviruses Associated with Influenza-Like Illnesses in the Philippines from 2006-2012 by Microneutralization and Molecular Techniques

OBJECTIVES

Human adenoviruses (HAdV) are known to cause a wide range of diseases including acute respiratory infections, conjunctivitis, and acute gastroenteritis. In this study, we aimed to determine the serotypes of HAdV in patients with influenza-like illness (ILI) in the Philippines from 2006-2012 and to describe the demographic and epidemiological characteristics of patients who tested positive for HAdV.

METHODS

Between 2006 and 2012, the Philippine National Influenza Centre detected HAdV in 1294 samples of patients with ILI. Serotype determination was done in select samples using microneutralization, polymerase chain reaction (PCR), and sequencing methods.

RESULTS

A total of 8 serotypes were identified (HAdV 1-7 and 11), with HAdV-2 (27.8%), and HAdV-3 (27.8%) being the most prevalent. The majority of HAdV infections were found in children below 5 years of age (79.9%).

CONCLUSIONS

The identification of HAdV circulating serotypes may serve as guide for designing disease intervention and control strategies and will provide important information regarding the contribution of this virus to respiratory infections, particularly in children, which remain a public health burden in the Philippines.

Enteric adenovirus epidemiology from historical fecal samples in Brazil (1998-2005): Pre-rotavirus vaccine era

Human adenovirus (HAdV) is recognized as frequent cause of acute gastroenteritis and enteric viruses can be preserved in frozen stored feces for long periods of times. The purpose of the present study was to investigate enteric HAdV genotypic diversity in archival fecal specimens stored from 1998 to 2005 in order to understand the natural history of HAdV in diarrheal patients in Brazil before rotavirus vaccine introduction. A total of 3346 specimens were tested for HAdV using conventional PCR. Genotypes were identified by sequencing. HAdV was detected in 6.8% (228/3346). Positivity was higher in children ≤ 5 years and males (p < 0.05). HAdV was most frequently observed during winter and spring seasons (p < 0.05). HAdV-F41 was the most prevalent genotype (59.2%;135/228), followed by HAdV-F40 (16.2%;37/228), HAdV-C1 (5.2%;12/228), HAdV-C2 (5.2%;12/228), HAdV-C5 (3.1%;7/228), HAdV-A12 (1.3%;3/228), HAdV-E4 (0.9%;2/228), HAdV-B3 (0.9%;2/228) and HAdV-B21 (0.4%;1/228). In 7.6% (17/228) only species D could be defined. HAdV-E4 strains were phylogenetic analyzed and classified as lineage (a)-like PG II. HAdV prevalence remained stable in Brazilian population, regardless rotavirus vaccine introduction. The predominant HAdV genotypes detected did not change over time, highlighting a high diversity of circulating strains in the country throughout decades. Due to the historical lack of HAdV genotyping surveillance in Brazil, HAdV-E4 epidemiology is virtually unknown in the country. The present study contributed significantly to the understanding of the natural history of HAdV in diarrheal patients in Brazil. The acquired data are important for clinical diagnosis, particularly for studies investigating enteric viruses' prevalence and molecular epidemiology of archival clinical specimens.

Adenovirus Isolated From a Cat Is Related to Human Adenovirus 1

An adenovirus (AdV) has been isolated from the rectal swab of a domestic cat (Felis catus) and named feline adenovirus (FeAdV) isolate. It replicates and causes cytopathological effects in many human, feline, other mammalian cell lines that have both Coxsackie-adenovirus-receptor and integrins. Its antigens cross-react with anti-human adenovirus antibodies in immunofluorescence and immunocytochemistry assays. Electron microscopy revealed typical extracellular icosahedral particles and pseudo arrays inside cells. Sequence analysis of hexon and fiber genes indicates that this virus might belong to human adenovirus (HAdV) C species and might be a variant of type 1. In the fiber protein, three altered amino acids occur in the shaft; four altered residues are found in the knob region as compared to a European HAdV might be type 1 isolate (strain 1038, D11). One alteration affects amino acid 442 forming an RGS motif in an alanine rich region that might be an alternative way to bind integrins with subsequent internalization. Substitutions in the hexon sequence are silent. As compared to published HAdV sequences, the fiber is related to the original American prototype and recently described Taiwanese HAdV 1 isolates, but the hexon sequences are related to adenovirus isolates from France, Germany, Japan, and Taiwan. Serology carried out on FeAdV infected M426 cells indicates a prevalence of IgG in 80% of domestic cats in Delaware, United States. FeAdV isolate seems to be a recently recognized virus with possible pathogenic effects and, simultaneous human and feline infections are possible. Further molecular and biological characterization of this feline adenovirus isolate, as well as studies on both human and feline epidemiology and pathomechanisms, especially in endangered big cats, are warranted. FeAdV might have further practical advantages. Namely, it could be utilized in both human and feline AIDS research, developed into diagnostic tools, and gene therapy vectors in the near future.

Transcriptome Sequencing Identifies Novel Immune Response Genes Highly Related to the Severity of Human Adenovirus Type 55 Infection

Human adenovirus type 55 (HAdV-55) is considered a highly virulent pathogen causing severe and even deadly pneumonia in immunocompetent people. The mechanisms of HAdV-55-induced initiation and progression of severe pneumonia remain ambiguous. In the current study, we endeavored to identify novel immune response genes which are substantially involved in the pathogenesis of severe inflammation in HAdV-55-infected patients. HAdV-55-infected patients with upper respiratory tract symptoms (minor patients) and pneumonia (severe patients) were enrolled. Through transcriptome sequencing and quantitative real-time PCR, the peripheral blood mononuclear cells of the patients were analyzed. We found that the expression of eight genes, including Il18, Il36b, Il17rc, Tnfsf10, Tnfsf11, Tnfsf14, Tnfsf15, and Il1a, were closely correlated with the severity of HAdV-55 infection. Most of these genes belong to interleukin-1 family or tumor necrosis factor (TNF) superfamily, respectively. The changes in gene expression were confirmed by Western blot assay. Our data will be crucial for deepening the understanding of the pathogenic mechanisms of severe pneumonia in HAdV-55 infection.

Respiratory viruses in patients with influenza-like illness in Senegal: Focus on human respiratory adenoviruses

Background

Human adenoviruses (HAdVs) are highly contagious pathogens that are associated with a wide spectrum of human illnesses involving the respiratory tract. In the present study, we investigate the epidemiologic and viral molecular features of HAdVs circulating in Senegal after 4 consecutive years of sentinel surveillance of influenza-like Illness cases.

Methodology and results

From January 2012 to December 2015 swabs were collected from consenting ILI outpatients. Adenoviral detection is performed by rRT-PCR with the Anyplex^™ II RV16 Detection kit (Seegene) and molecular characterization was performed using a partial hexon gene sequence. 6381 samples were collected. More than half of patients (51.7%; 3297/6381) were children of ≤ 5 years. 1967 (30.8%) were positive for HAdV with 1561 (79.4%) found in co-infection with at least one another respiratory virus. The most common co-detections were with influenza viruses (53.1%; 1045/1967), rhinoviruses (30%; 591/1967), enteroviruses (18.5%; 364/1967) and RSV (13.5%; 266/1967). Children under 5 were the most infected group (62.2%; 1224/1967; p <0.05). We noted that HAdV was detected throughout the year at a high level with detection peaks of different amplitudes without any clear seasonality. Phylogenetic analysis revealed species HAdV-C in majority, species HAdV-B and one HAdV- 4 genome type. The 9 HAdV-B species like strains from Senegal grouped with genome types HAdV-7, HAdV-55 and HAdV-11 as shown by a phylogenetic branch with a high bootstrap value of (88%).

Conclusion

In conclusion, the results of the present study suggest strong year-round HAdV activity in Senegal, especially in children up to 5 years of age. Molecular studies revealed that the dominant species in circulation in patients with ILI appears to be HAdV-C and HAdV-B species. The circulation of though HAdV-7 and HAdV-55 genome types is of note as these serotypes are recognized causes of more severe and even fatal acute respiratory infections.

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

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.

Adenoviruses and acute respiratory infections in children living in an equatorial area of Brazil

Human adenoviruses (HAdVs) are important respiratory pathogens, found in 2–27% of acute respiratory infection (ARI) cases. Few studies have analysed the diversity of species and types of HAdVs associated with ARI in Brazil. The purpose of this study was to determine the circulation patterns of the different HAdV species and respective types associated with ARI in children in the city of Fortaleza, northeastern Brazil. HAdVs were screened by an indirect immunofluorescence assay, and subsequently identified as species and types by PCR and sequencing of the hexon gene (HVR1–HVR6). Between 2001 and 2013, a total of 290 HAdV strains were detected, 190 of which were identified as belonging to the HAdV-B, -C and -E species. Seven types of HAdVs circulated in the studied population during the analysed period, with HAdV-3 being predominant.

[Application of molecular assay for adenovirus detection among different pediatric patients]

OBJECTIVE:

Adenoviruses play an important role in the etiology of severe acute lower respiratory infection, especially in young children. The aim of the present study was to evaluate the Human Adenovirus (HAdV) detection by different methods (Direct Fluorescence Assay DFA and Nested Polymerase Chain Reaction nested PCR), among samples collected from different groups of pediatric patients.

METHODS:

Collection of samples was made in children with congenital heart disease (CHD 123 nasal aspirates collected in the years of 2005, 2007 and 2008) and in community children (CC 165 nasal aspirates collected in 2008). Children were eligible if they presented acute respiratory infection (ARI) of probable viral etiology, within up to 7 days of symptoms' onset. All studied samples were evaluated by DFA and nested PCR assay.

RESULTS:

Of the 290 samples included during the study period, 43 (14.8%) were positive on at least one test: 17/165 (10.3%) of the CC and 26/125 (20.8%) of the CHD children. The nested PCR detection rates in the community children were 15/165 (9.1%), and for children with CHD, 24/125 (19.2%). Molecular method showed higher detection rates when compared to the DFA test (p<0.001). Univariate analysis showed that children with congenital heart disease presented a significantly higher chance for acquiring the HAdV (Odds Ratio 2.3; 95% CI: 1.18-4.43).

CONCLUSIONS:

Based on data obtained in the present evaluation, we suggest that a routine surveillance should be performed in high risk patients by molecular methods, thus improving diagnostic flow and efficiency.

Molecular characterization of influenza viruses collected from young children in Uberlandia, Brazil - from 2001 to 2010

Background

Influenza remains a major health problem due to the seasonal epidemics that occur every year caused by the emergence of new influenza virus strains. Hemagglutinin (HA) and neuraminidase (NA) glycoproteins are under selective pressure and subjected to frequent changes by antigenic drift. Therefore, our main objective was to investigate the influenza cases in Uberlândia city, Midwestern Brazil, in order to monitor the appearance of new viral strains, despite the availability of a prophylactic vaccine.

Methods

Nasopharyngeal samples were collected from 605 children less than five years of age presenting with acute respiratory disease and tested by immunofluorescence assay (IFA) for detection of adenovirus, respiratory syncytial virus, parainfluenza virus types 1, 2, and 3 and influenza virus types A and B. A reverse transcription-PCR (RT-PCR) for influenza viruses A and B was carried out to amplify partial segments of the HA and NA genes. The nucleotide sequences were analyzed and compared with sequences of the virus strains of the vaccine available in the same year of sample collection.

Results

Forty samples (6.6%) were tested positive for influenza virus by IFA and RT-PCR, with 39 samples containing virus of type A and one of type B. By RT-PCR, the type A viruses were further characterized in subtypes H3N2, H1N2 and H1N1 (41.0%, 17.9%, and 2.6%, respectively). Deduced amino acid sequence analysis of the partial hemagglutinin sequence compared to sequences from vaccine strains, revealed that all strains found in Uberlândia had variations in the antigenic sites. The sequences of the receptor binding sites were preserved, although substitutions with similar amino acids were observed in few cases. The neuraminidase sequences did not show significant changes. All the H3 isolates detected in the 2001-2003 period had drifted from vaccine strain, unlike the isolates of the 2004-2007 period.

Conclusions

These results suggest that the seasonal influenza vaccine effectiveness could be reduced because of A H3N2 variants that circulated in 2001-2003 years. Thus, an early monitoring of variants circulating in the country or in a region may provide important information about the probable efficacy of the vaccine that will be administered in an influenza season.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-0817-z) contains supplementary material, which is available to authorized users.

Serotype determination of adenoviruses in children with respiratory infection

OBJECTIVE

To determine adenovirus serotypes among children with acute respiratory infection (ARI) in Khoozestan province, Iran during years 2010-2011.

METHODS

One hundred sixty three nasopharyngeal swabs were collected from children between 1 and 15 y who were hospitalized for the acute respiratory infection. The viral DNA was extracted from the nasopharyngeal swabs and adenoviruses were detected by Nested PCR. Positive PCR samples were sequenced in order to confirm the adenovirus serotypes.

RESULTS

Out of 163 samples, 30 (18.4 %) were positive for adenoviruses by nested PCR. Twenty two PCR products were sequenced and recognized as Ad5 and Ad2 serotypes including 19 (86.3 %) Ad5 and 3 (13.7 %) Ad2.

CONCLUSIONS

This study reveals that adenoviruses with Ad5 predominance are important cause of respiratory tract infection in children.

Clinical and epidemiological aspects related to the detection of adenovirus or respiratory syncytial virus in infants hospitalized for acute lower respiratory tract infection

OBJECTIVE

To characterize and compare clinical, epidemiological, and laboratory aspects of infants with acute lower respiratory infection (ALRI) associated with the detection of adenovirus (ADV) or respiratory syncytial virus (RSV).

METHODS

A preliminary respiratory infection surveillance study collected samples of nasopharyngeal aspirate (NPA) for viral research, linked to the completion of a standard protocol, from children younger than two years admitted to a university hospital with ALRI, between March of 2008 and August of 2011. Polymerase chain reaction (PCR) was used for eight viruses: ADV, RSV, metapneumovirus, Parainfluenza 1, 2, and 3, and Influenza A and B. Cases with NPA collected during the first 24 hours of admission, negative results of blood culture, and exclusive detection of ADV (Gadv group) or RSV (Grsv group) were selected for comparisons.

RESULTS

The preliminary study included collection of 1,121 samples of NPA, 813 collected in the first 24 hours of admission, of which 50.3% were positive for at least one virus; RSV was identified in 27.3% of cases surveyed, and ADV was identified in 15.8%. Among the aspects analyzed in the Gadv (n = 58) and Grsv (n = 134) groups, the following are noteworthy: the higher mean age, more frequent prescription of antibiotics, and the highest median of total white blood cell count and C-reactive protein values in Gadv.

CONCLUSIONS

PCR can detect persistent/latent forms of ADV, an aspect to be considered when interpreting results. Additional studies with quantitative diagnostic techniques could elucidate the importance of the high frequency observed.

Immunochemistry of adenoviruses: limitations and new horizons of gene therapy

Adenoviruses have increasingly been recognized as significant viral pathogens causing high morbidity and mortality especially among immunocompromised individuals such as transplant recipients and AIDS patients. Through the infection process, after the adenovirus fiber and penton are bonded to cell surface receptors through special amino acid moieties, secondary messengers activate protein kinases, pro-inflammatory cytokines and chemokines. Serotype and species specific antibodies also are induced. Recombinant human adenoviruses have been pivotal in the development of gene therapy strategies and have shown a great promise for the treatment of genetic disorders and malignancies. Recent studies have enlightened their harmful immunological effects dependent on fiber and hexon polypeptide structure and receptor binding. Pre-existing antibodies or those elicited by vectors neutralize input recombinant adenovirus particles rendering them ineffective. Mediators induce serious even lethal side effects and cytotoxic reactions which extinguish transgene expression. To overcome these difficulties new strategies are required in the application of recombinant adenoviruses to redirect vector entry from the natural receptors to alternative binding sites or using rare human or animal adenovirus fiber molecules to modify the native fiber structure by altering amino acid structure and creating chimeric fibers. This requires searching for, isolating and characterizing new serotypes, mutants or variants for new generation vectors. Human adenovirus 1 feline isolate (feline adenovirus) might fulfil these criteria.

Molecular characterization of human adenovirus infection in Thailand, 2009-2012

Background

Human adenovirus (HAdV) can cause a wide spectrum of human diseases worldwide.

Methods

Using PCR and sequence analysis, we investigated HAdV infection prevalence in the Thai population for four years from January 2009 to December 2012. We collected Nasopharyngeal swab/aspirate (NP) specimens from patients in Bangkok, Khon Kaen, and Nakhon Si Thammarat province and fecal specimens only from Bangkok and Khon Kaen province.

Results

We observed HAdV infection in 1.04% (82/7,921) of NP samples and in 5.84% (76/1,301) of fecal specimens. HAdV-B3 (32%) and HAdV-C1 (31%) were the genotypes most commonly associated with NP specimens followed by HAdV-C2 (13%) and HAdV-C5 (12%). In fecal specimens, we found that 25% harbored HAdV-F41 followed by HAdV-C1 (18%), HAdV-C2 (16%), and HAdV-B3 (13%). Out of all population subsets, children below the age of 3 years were the most likely to be HAdV positive (63.29%). In addition, HAdV infection occurred throughout the year without a seasonal distribution pattern, although HAdV infection of NP samples peaked from January-April while HAdV infection peaked from January to March and then again from May to July in fecal samples.

Conclusions

This study has for the first time reported the HAdV infection rate in Thai NP and fecal specimens from 2009–2012. We observed that HAdV-B3 and HAdV-C1 were commonly found in NP specimens, and that HAdV-F41 was the most prevalence in fecal specimens in Thailand during the study period.

Adenovirus respiratory tract infections in Peru

Background

Currently, there is a paucity of data regarding human adenovirus (HAdv) circulation in Andean regions of South America. To address this shortcoming, we report the clinical, phylogenetic, and epidemiologic characteristics of HAdv respiratory tract infection from a large sentinel surveillance study conducted among adults and children in Peru.

Methods/Principal Findings

Oropharyngeal swabs were collected from participants visiting any of 38 participating health centers, and viral pathogens were identified by immunofluorescence assay in cell culture. In addition, molecular characterization was performed on 226 randomly selected HAdv samples. Between 2000 and 2010, a total of 26,375 participants with influenza-like illness (ILI) or severe acute respiratory infection (SARI) were enrolled in the study. HAdv infection was identified in 2.5% of cases and represented 6.2% of all viral pathogens. Co-infection with a heterologous virus was found in 15.5% of HAdv cases. HAdv infection was largely confined to children under the age of 15, representing 88.6% of HAdv cases identified. No clinical characteristics were found to significantly distinguish HAdv infection from other respiratory viruses. Geographically, HAdv infections were more common in sites from the arid coastal regions than in the jungle or highland regions. Co-circulation of subgroups B and C was observed each year between 2006 and 2010, but no clear seasonal patterns of transmission were detected.

Conclusions/Significance

HAdv accounted for a significant fraction of those presenting with ILI and SARI in Peru and tended to affect the younger population disproportionately. Longitudinal studies will help better characterize the clinical course of patients with HAdv in Peru, as well as determine the role of co-infections in the evolution of illness.