Journal of medical virology
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We have previously reported that concanavalin A-immobilized polystyrene nanospheres (Con A-NS) could efficiently capture HIV-1 particles and that intranasal immunization with inactivated HIV-1-capturing nanospheres (HIV-NS) induced vaginal anti-HIV-1 IgA antibody response in mice. In this study, to evaluate the protective effect of immunization, each three macaques was intranasally immunized with Con A-NS or inactivated simian/human immunodeficiency virus KU-2-capturing nanospheres (SHIV-NS) and then intravaginally challenged with a pathogenic virus, SHIV KU-2. After a series of six immunizations, vaginal anti-HIV-1 gp120 IgA and IgG antibodies were detected in all SHIV-NS-immunized macaques. ⋯ Plasma anti-HIV-1 gp120 IgA and IgG antibodies were induced more rapidly in the SHIV-NS-immunized macaques than in the controls. The rapid antibody responses having neutralizing activity might contribute to the clearance of the challenge virus. Thus, SHIV-NS-immunized macaques exhibited partial protection to vaginal and systemic challenges with SHIV KU-2.
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Human metapneumovirus (hMPV) was first described in Dutch children with acute respiratory symptoms. A prospective analysis of the epidemiology, clinical manifestation, and seroprevalence of hMPV and other respiratory viruses in South African children referred to hospital for upper or lower respiratory tract infection were carried out during a single winter season, by using RT-PCR, viral culture, and enzyme-linked immunosorbent assays. In nasopharyngeal aspirates from 137 children, hMPV was detected by RT-PCR in 8 (5.8%) children (2-43 months of age) as a sole viral pathogen, respiratory syncytial virus (RSV) in 21 (15%), influenza A virus in 18 (13%) and influenza B virus in 20 (15%). ⋯ No statistically significant differences were found between hMPV, RSV, and influenza virus infected groups with regard to clinical signs and symptoms and chest radiograph findings. The seropositive rate of hMPV specific IgG antibodies was 92% in children aged 24-36 months, the oldest seronegative child in our study was 7 years and 6 months of age. In conclusion, hMPV contributes to upper and lower respiratory tract morbidity in South African children.
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The humoral immune response to Respiratory Syncytial Virus (RSV) was investigated in old and young adults. RSV was identified by culture and/or reverse transcription polymerase chain reaction (RT-PCR) in 52 elderly (mean age 74 years) and 15 young adults (mean age 33 years) with respiratory illness. ⋯ The exuberant antibody response seen in older adults may be a reflection of greater viral load and antigenic stimulation and/or a shift from Th1 to Th2 dominant immune response with aging. The relationship of immune response to disease pathogenesis in older persons deserves further study.
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Comparative Study
Influenza virological surveillance in children: the use of the QuickVue rapid diagnostic test.
New rapid diagnostic methods are needed to identify influenza infections to improve virological surveillance usually undertaken with conventional time-consuming, complex, and even expensive laboratory methods. Another reason for using a rapid test is to avoid inappropriate therapy, particularly in children, where use of antibiotics inappropriately and high influenza-related rates of hospitalisation are described. During two winter seasons, the performance of the QuickVue Influenza test (QV) was evaluated in children under 14 presenting with influenza like illness, and compared the results with those obtained from sentinel network surveillance using standard protocols for the sample collection and the laboratory analysis by virus culture and reverse transcription-polymerase chain reaction (RT-PCR). ⋯ The results showed a better sensitivity (54.5%) of the test in comparison with virus culture and RT-PCR assays. The data indicate that rapid QV testing in the physician office setting, using these easily obtained samples, may be too insensitive to be useful for surveillance and for immediate clinical management of children presenting with influenza-like illness. Nevertheless, the QV test may be a valuable diagnostic tool if used in laboratory, as a rapid screening test.
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The persistence of rhinovirus and enterovirus RNAs was studied in the nasal secretions of children with acute expiratory wheezing (median age: 1.7 years). On admission, 84 samples from 161 (52%) children admitted to hospital were positive by reverse transcriptase-polymerase chain reaction (RT-PCR), which detects rhino- and enteroviruses simultaneously. Of the samples, 26 (16%) were positive for rhinovirus, 29 (18%) enterovirus and 29 (18%) nontypable rhino-enterovirus. ⋯ Thirteen of the 79 (16%) asymptomatic control children were PCR-positive for respiratory picornavirus. Five of the 13 (38%) PCR-positive children developed respiratory symptoms in the following week. The study shows that after the onset of symptomatic respiratory infection enterovirus RNA may take 2-3 weeks and rhinovirus RNA 5-6 weeks to disappear from nasal mucus.