Background/aim: Respiratory syncytial virus (RSV) is one of the main
causes of bronchiolitis and pneumonia in infants and young children. The aims
of the present study were to evaluate the role of RSV in children >2 years
old hospitalized with community-acquired pneumonia (CAP) and to type the
circulating RSV strains. Materials and Methods: Serum and throat swab samples
were taken upon admission from Greek children aged > 2 years, hospitalized
with atypical CAP, and when possible, a second serum sample was also taken. RSV
IgG and IgM antibodies were determined by Enzyme Linked Immunosorbent Assay
(ELISA), while throat swab samples were tested by nested RT-PCR. Additional
serological testing was performed to find out probable co-infections.
Results: A total of 101 children with atypical CAP were included in the study,
aged 2.5-14 years (median 8.25). RSV IgM antibodies were detected in 21 (20.7%)
cases, either in the first or/and in the second serum sample, while RSV genome
was detected in 11 out of 15 (73%) IgM-positive patients, which were further
tested by PCR. PCR-positive results were obtained up to the 7th day
of illness. Among the 11 cases, one was of type B, and all the rest were of
type A. The median age of the RSV-positive children was 4 years (range 3-13
years). Although RSV was detected in all seasons, the majority of cases (31%)
were detected in winter. Co-infection was detected in 3 cases (two with Mycoplasma
pneumoniae and one with adenovirus).
Conclusions: Apart from the known role of RSV as the most important pathogen
causing acute respiratory disease in infants and young children, it is also a
significant viral pathogen in older children hospitalized because of CAP.
Genetic typing provides further insight into the epidemiology of the disease.
The aim of this study was to detect and determine the genetic variation of HIV-1 in Greece and to analyze the phylogenetic relationships and transmission dynamics of identified variants. Eighty-six blood samples from HIV-1 seroconverted patients of different risk groups were collected from the AIDS clinic, AHEPA Hospital, Thessaloniki, Greece. Retroviral DNA was extracted from uncultured peripheral blood mononuclear cells. HIV-1 DNA sequences encoding a 500-bp fragment of the gp120 C2-C3 region were amplified from each study subject, and they were genetically subtyped by heteroduplex mobility assay and DNA sequencing. Genetic distances and phylogenetic relationships of DNA sequences were estimated using PHYLIP software. Our results revealed that 82 out of 86 (95.3%) subjects carried subtype B sequences, while four (4.7%) carried subtype A sequences. Subtype A in Greek individuals not having traveled abroad was documented. An average of intrasubtype B genetic divergence of 15% was noted. Our findings demonstrate the presence of at least two genetic subtypes of HIV-1 in northern Greece – subtype B and subtype A. The predominant subtype is subtype B, which was transmitted into Greece by multiple sources. Our observations lend support to the argument that the distribution of HIV-1 subtypes is determined by founder effects or other processes rather than any tropism for particular cell types or mode of transmission. © 2000 Éditions scientifiques et médicales Elsevier SAS