Human respiratory syncytial virus (HRSV) is a major cause of serious lower respiratory tract illness in infants, young children, and the elderly. To characterize the circulation patterns of HRSV strains, nucleotide sequencing of the C-terminal region of the G protein gene was performed on 34-53 isolates obtained from 5 communities during 1 epidemic year, representing distinct geographical locations in North America. Phylogenetic analysis revealed that 5-7 HRSV genotypes, including 1 or 2 predominant strains, circulated in each community. The patterns of genotypes were distinct between communities, and less diversity was seen between strains of the same genotype within than between communities. These findings are consistent with HRSV outbreaks' being community based in nature, although transmission of viruses between communities may occur. Several strains are probably introduced or circulate endemically in communities each year, and local factors-possibly immunity induced by previous years' strains-determine which strains predominate during an HRSV season.

Respiratory syncytial virus (RSV) is the most commonly identified viral agent of acute respiratory tract infection (ARIAcute respiratory tract infection (ARI) is the leading killer of children in the world (1.9 million per year), with the greatest number of deaths occurring in developing countries (49). Onefourth (2.5 million) of the total deaths among children less than 5 years of age occur in India (1), and approximately 20% of these are due to ARI (0.5 million) (35,49). Viruses are found in 20 to 40% of children hospitalized with ARIs in India, with respiratory syncytial virus (RSV) being one of the most frequently identified pathogens (15,22,23).RSV strains vary genetically and antigenically and have been classified into two broad groups, groups A and B (2,11,16,25), with additional variability detected within the groups (4, 40). Antigenic variability is thought to contribute to the capacity of the virus to establish reinfections throughout life and may pose a challenge to vaccine design. Future planning for vaccine development will require an understanding of the genetic composition of the RSV strains circulating among target populations.The RSV G protein is a type II integral membrane protein (48) and shows the highest degree of divergence both between and within the two groups (16). The G protein is highly glycosylated, and it is the target for neutralizing and protective immune responses. Variability in the G protein gene is concentrated in the extracellular domain, which consists of two hypervariable regions separated by a central conserved region of 13 amino acids (16). The second variable region, which corresponds to the C-terminal region of the G protein, reflects overall G protein gene variability and has been analyzed in molecular epidemiological studies (5, 33).The objective of the present study was to evaluate the genetic diversity of RSV strains collected in a longitudinal study of ARI from young children in two rural villages in India and from children with ARI seen in an urban hospital. Information about distribution of RSV genotypes in India will be beneficial to the development and implementation of RSV vaccines. MATERIALS AND METHODSClinical samples and diagnosis of RSV infection. The details of this epidemiological study will be described in another report that is under preparation; the results of the molecular epidemiologic study are provided here. Newborns from two rural villages, Nawadha and Mujheri, of Ballabgarh block near Delhi, were enrolled between October 2001 and December 2004 and monitored up to 3 years of age or to the end of the study, March 2005. Two hundred eighty-one children were enrolled, and the total follow-up was 441 child-years. The children enrolled in the study were seen weekly in their homes; approximately 85% of these visits were completed. ARIs were classified according to World Health Organization definitions (50), and nasopharyngeal aspirates (NPAs) were collected at each episode of ARI. ARI was defined as the presence of a cough or difficulty in breathing tha...

SUMMARY Respiratory syncytial virus (RSV) is a major cause of viral lower respiratory tract infections among infants and young children in both developing and developed countries. There are two major antigenic groups of RSV, A and B, and additional antigenic variability occurs within the groups. The most extensive antigenic and genetic diversity is found in the attachment glycoprotein, G. During individual epidemic periods, viruses of both antigenic groups may cocirculate or viruses of one group may predominate. When there are consecutive annual epidemics in which the same group predominates, the dominant viruses are genetically different from year to year. The antigenic differences that occur among these viruses may contribute to the ability of RSV to establish reinfections throughout life. The differences between the two groups have led to vaccine development strategies that should provide protection against both antigenic groups. The ability to discern intergroup and intragroup differences has increased the power of epidemiologic investigations of RSV. Future studies should expand our understanding of the molecular evolution of RSV and continue to contribute to the process of vaccine development.

Two antigenic sites recognized by neutralizing monoclonal antibodies (MAbs) directed against the fusion (F) glycoprotein of human respiratory syncytial virus were mapped on the primary structure of the protein by (i) the identification of amino acid substitutions selected in antibody-escape mutants and (ii) the reactivity of synthetic peptides with MAbs. The first site contained several overlapping epitopes which were located within the trypsin-resistant amino-terminal third of the large F1 subunit. Only one of these epitopes was faithfully reproduced by a short synthetic peptide; the others might require specific local conformations to react with MAbs. The second antigenic site was located in a trypsin-sensitive domain of the F1 subunit towards the carboxy-terminal end of the cysteine-rich region. One of these epitopes was reproduced by synthetic peptides. In addition, mutagenized F protein with a substitution of serine for arginine at position 429 did not bind MAbs to the second site. These results are discussed in terms of F protein structure and the mechanisms of virus neutralization.

BackgroundAcute respiratory infection (ARI) is a major killer of children in developing countries. Although the frequency of ARI is similar in both developed and developing countries, mortality due to ARI is 10–50 times higher in developing countries. Viruses are common causes of ARI among such children, yet the disease burden of these infections in rural communities is unknown.Methodology/Principal FindingsA prospective longitudinal study was carried out in children enrolled from two rural Indian villages at birth and followed weekly for the development of ARI, classified as upper respiratory infection, acute lower respiratory infection (ALRI), or severe ALRI. Respiratory syncytial virus (RSV), influenza, parainfluenza viruses and adenoviruses in nasopharyngeal aspirates were detected by direct fluorescent antibody testing (DFA) and, in addition, centrifugation enhanced culture for RSV was done. 281 infants enrolled in 39 months and followed until 42 months. During 440 child years of follow-up there were 1307 ARIs, including 236 ALRIs and 19 severe ALRIs. Virus specific incidence rates per 1000 child years for RSV were total ARI 234, ALRI 39, and severe ALRI 9; for influenza A total ARI 141, ALRI 39; for INF B total ARI 37; for PIV1 total ARI 23, for PIV2 total ARI 28, ALRI 5; for parainfluenza virus 3 total ARI 229, ALRI 48, and severe ALRI 5 and for adenovirus total ARI 18, ALRI 5. Repeat infections with RSV were seen in 18 children.Conclusions/SignificanceRSV, influenza A and parainfluenza virus 3 were important causes of ARI among children in rural communities in India. These data will be useful for vaccine design, development and implementation purposes.

Background: Acute lower respiratory tract infections (ALRI) are the major cause of morbidity and mortality in young children worldwide. Information on viral etiology in ALRI from India is limited. The aim of the present study was to develop a simple, sensitive, specific and cost effective multiplex PCR (mPCR) assay without post PCR hybridization or nested PCR steps for the detection of respiratory syncytial virus (RSV), influenza viruses, parainfluenza viruses (PIV1-3) and human metapneumovirus (hMPV). Nasopharyngeal aspirates (NPAs) were collected from children with ALRI ≤ 5 years of age. The sensitivity and specificity of mPCR was compared to virus isolation by centrifugation enhanced culture (CEC) followed by indirect immunofluorescence (IIF).

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Rationale: Recently, respiratory syncytial virus (RSV) RNA has been identified by reverse transcriptase-polymerase chain reaction (RT-PCR) from a high percentage of patients with stable chronic obstructive pulmonary disease (COPD). These data raise the possibility of persistent low-grade infection in this population, which could have implications in COPD pathogenesis. Objectives: RSV persistence was investigated by testing respiratory secretions from subjects with COPD during illness and at regular intervals over 1 yr. Methods: Nasal and sputum samples from subjects with COPD were tested by one-tube nested RT-PCR for RSV every 2 mo and during respiratory illnesses for 1 yr. Subjects positive for RSV were evaluated weekly until negative in two consecutive samples. Nasal secretions and serum were tested for RSV antibody. A rise of fourfold or greater was defined as evidence of RSV infection. Results: A total of 112 patients were enrolled and the illnesses of 92 patients were evaluated. RSV was detected by RT-PCR in 6/92 (6.5%) illness nasal samples versus 0/685 routine nasal samples and in 5/69 (7.2%) illness sputum samples versus 3 /315 (0.9%) routine. Four additional RSV infections were identified by serum antibody responses. Of the RSV infections 86% were associated with serum or nasal antibody responses and 73% had symptoms of acute respiratory illness. Conclusions: Most RSV infections in patients with COPD are associated with symptomatic respiratory illnesses and measurable immune responses. Our data do not support the concept of RSV persistence in this population. Keywords: chronic obstructive pulmonary disease exacerbation; persistent infection; viral infectionChronic obstructive pulmonary disease (COPD) is a group of disorders characterized by airflow obstruction that can be associated with breathing-related symptoms such as chronic cough, dyspnea, and wheezing (1). It is estimated that approximately 24 million adults in the United States have impaired lung function due to COPD. During 2000, COPD was responsible for 8 million physician office visits, 1.5 million emergency room visits, 726,000 hospitalizations, and 119,000 deaths. Recurrent acute exacerbations of COPD contribute substantially to the morbidity and mortality of this condition and may be due to infections with bacteria, viruses, or both (2-4). In studies of COPD exacerbation, respiratory syncytial virus (RSV) has been identified with variable frequency ranging from 0.8 to 22% depending on the diagnostic methods used (5-16). Recently investigators from the United Kingdom and Germany identified RSV RNA by reverse In our laboratory, we have developed a sensitive and specific real-time, one-tube nested RT-PCR for the diagnosis of RSV in adults (19,20). Because the assay is performed without opening the reaction tube, PCR contamination has been markedly reduced while the sensitivity of a nested assay is retained. Therefore, we sought to explore the question of RSV persistence in patients with COPD by testing upper-and lower-respiratorytract secreti...