Infections of the central nervous system of suspected viral origin: a collaborative study from Finland.

We studied 3231 patients with acute central nervous system (CNS) symptoms of suspected viral origin to elucidate the current etiologic spectrum. In 46% of the cases, a viral finding was observed. Varicella-zoster virus (VZV) was the main agent associated with encephalitis, as well as meningitis and myelitis. VZV comprised 29% of all confirmed or probable etiologic agents. Herpes simplex virus (HSV) and enteroviruses accounted 11% each, and influenza A virus 7%. VZV seems to have achieved a major role in viral infections of CNS. In encephalitis in our population, VZV is clearly more commonly associated with these neurological diseases than HSV. The increase in VZV findings may in part be a pseudophenomenon due to improved diagnostic methods, however, a true increase may have occurred and the pathogenetic mechanisms behind this should be elucidated.

Treatment of acute otitis media with an antiadhesive oligosaccharide: a randomised, double-blind, placebo-controlled trial.

BACKGROUND: Antiadhesive compounds are promising candidates for prevention or treatment of infections. We have investigated the efficacy of such an agent, 3'-sialyllacto-N-neotetraose (NE-1530), given intranasally for prophylaxis of acute otitis media and for effect on nasopharyngeal carriage of bacteria. METHODS: We did a randomised, double-blind placebo-controlled study at one study site. 507 healthy children were randomly assigned either NE-1530 (n=254) or placebo (253) as intranasal sprays twice daily during 3 months. The children were examined by the study physicians once a month and during illness. Treatment efficacy was estimated from Cox proportional hazards model. A sample of nasopharyngeal secretion was taken at every visit for culture of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Adverse events were recorded in study diaries. FINDINGS: At least one event of acute otitis media was diagnosed in 108 (43%) of 254 children in the NE-1530 group and in 86 (34%) of 253 children in the placebo group. The efficacy of treatment was negative, -27% (95% CI -68 to 5; p=0.10). The nasopharyngeal carriage of S pneumoniae, H. influenzae, and M. catarrhalis was not affected by treatment, and the adverse event profiles were almost identical for NE-1530 and placebo. INTERPRETATION: NE-1530 did not have a beneficial effect on the occurrence of acute otitis media or on the nasopharyngeal carriage of bacteria in children.

Single-dose and steady-state pharmacokinetics of a new oral suspension of ciprofloxacin in children.

OBJECTIVE: Quinolones are used ever increasingly in pediatrics, although officially they are still contraindicated. Lack of evidence of arthropathic effects in human offspring favors their use, but little is known about the pharmacokinetics of oral or parenteral ciprofloxacin in children, especially those without cystic fibrosis. DESIGN: We studied 16 non-cystic fibrosis patients ranging in age from 0.3 to 7.1 years to whom the new suspension formulation of ciprofloxacin (10 mg/kg body weight) was given orally three times daily. Single-dose and steady-state pharmacokinetic parameters were elucidated. RESULTS: Ciprofloxacin was rapidly absorbed. The maximum plasma concentrations, with the means varying from 1.7 to 3.6 mg/L, were reached within 1 hour, almost regardless of whether single-dose administration or steady state. The mean oral clearance was lower in children <6 years of age than in those >/=6 years. Terminal half-life values, with the means varying only between 4.2 and 5.1, suggest that dosing recommendations based on body weight are pertinent, although caution should be exercised in small infants. No arthropathic or other adverse events attributable to ciprofloxacin suspension were observed. CONCLUSION: A dose of the suspension form of ciprofloxacin of 10 mg/kg body weight given orally three times daily seems appropriate in children, provided the drug is clearly indicated.

Epidemiology of encephalitis in children. A prospective multicentre study.

UNLABELLED: We found 175 cases with acute encephalitis in a population of 791,712 children aged 1 month-15 years during a 2-year surveillance period in 1993-1994. The overall incidence was 10.5/100,000 child-years with the highest figure in children < 1 year of age, 18.4/100,000 child-years. The microbial diagnosis was considered proven or suggested in 110 cases (63%); varicella zoster, respiratory and enteroviruses comprised 61% of these, and adeno, Epstein Barr-, herpes simplex and rota viruses comprised 5% each. A clearcut change seems to have occurred in the aetiology of encephalitis. Mumps, measles, and rubella virus associated encephalitides have been almost eliminated. Varicella zoster, respiratory, and enteroviruses have increased in frequency and occur in younger age groups. New causes were identified, especially Chlamydia pneumoniae and HHV-6. Our data should assist in making a specific diagnosis and defining appropriate antimicrobial therapy. CONCLUSIONS: The spectrum of encephalitis in children has changed due to vaccination programs. The incidence, however, appears to be about the same due to increasing frequency of other associated old and new microbes.

RSV infection complicating the therapy of pediatric malignancies: report of six cases.

We describe a series of six patients with symptomatic respiratory syncytial virus (RSV) infections while receiving anticancer chemotherapy. Particularly during epidemics in the general population, RSV remains a potential cause for morbidity and even mortality among children immunocompromised through the administration of anticancer chemotherapy and especially those being transplanted. We emphasize the importance of rapid diagnostics as well as prevention of the spread of the virus in a pediatric hematology/oncology unit.

Rubella immunity and morbidity: impact of different vaccination programs in Finland 1979-1992.

As the previous vaccination of 11- to 13-year-old girls proved ineffective, nationwide vaccination of preschool children with 2 doses of combined vaccine against measles, mumps, and rubella was started in Finland in 1982. To study the impact of vaccination, age-stratified rubella immunity and the occurrence of serologically verified rubella cases were determined using the computerized data of our diagnostic virus laboratory. The analysis covered the period 1979-1992, included all ages, and was based on the test results from 94,000 sera. By 1992, the seropositivity rate was 92-100% in 2- to 15-year-old children, remained high in females of all ages, but showed a gap in 16- to 19-year-old males. The number of verified rubella cases decreased to about 1/100, but outbreaks still occurred until 1991, when most cases were among adolescent males. The better protection of women was due to the vaccination of prepubertal girls since 1975. No congenital rubella infections were diagnosed after 1986. The 2-dose immunization of preschool children, complemented by selective vaccination of certain other groups, has resulted in excellent immunity in children and young adults, and practically eliminated rubella from the country.

Virus inactivation during intravenous immunoglobulin production.

Effects of time, temperature, pH and stabilizers (i.e. medium) on inactivation of lipid-enveloped model viruses, Semliki Forest and vesicular stomatitis viruses in the production process of intravenous immunoglobulin were investigated on a laboratory scale. The lowering of pH, the raising of temperature and the increasing of incubation time improved the inactivation effect. However, small changes in pH and stabilizer concentrations did not influence the results. Inactivation was not linear and a clear tailing off could be seen. Therefore, for complete virus inactivation incubation times longer than 20 h are necessary. Inactivation took place much more rapidly in intravenous immunoglobulin solution than in intramuscular immunoglobulin solution. Processing steps such as freeze-dying in the presence of ethanol or storage of intramuscular immunoglobulin in the liquid state at pH7 only partially inactivated these viruses.

Cytomegalovirus is frequently isolated in bronchoalveolar lavage fluid of bone marrow transplant recipients without pneumonia.

We prospectively studied the presence of cytomegalovirus in bronchoalveolar lavage through virus isolation in 21 bone marrow transplant recipients before and after transplantation. All 14 lavage specimens collected before bone marrow transplantation were negative for cytomegalovirus. During the period from 20 to 90 days after transplantation, 12 of 24 lavage specimens (50%) from 14 patients without lung problems were positive for cytomegalovirus. Cytomegalovirus was isolated from 4 of 10 lavage specimens (40%) in 7 patients with pneumonia during the same interval. We conclude that culture for cytomegalovirus in bronchoalveolar lavage fluid is not a reliable method for establishing the virus's causative role in pneumonia soon after bone marrow transplantation. Among 14 patients in whom bronchoalveolar lavage was done at an asymptomatic stage, 6 of 9 patients with cytomegalovirus and none of 5 without cytomegalovirus in the lavage fluid later developed pneumonia. All of the patients subsequently developing pneumonia also had acute graft-versus-host disease, suggesting an immunopathologic mechanism, possibly triggered by cytomegalovirus, for cytomegalovirus-associated pneumonia.

The seroepidemiology of Chlamydiae in Finland over the period 1971 to 1987.

The seroepidemiology of chlamydial infections in the Finnish population was studied by analysing the prevalence of chlamydial complement fixing (CF) antibodies in patients sera sent for virus serological screening tests over 17 years from 1971 to 1987. The total number of sera studied was over 160,000. In the early 1970s, the prevalence of chlamydial CF antibodies (CF titres greater than or equal to 8) was low (less than 2%), but later the proportion of seropositive cases rose, and in 1976, 18% of sera contained antibodies. In 1984, the seropositivity rate was over 31%. The prevalence of high chlamydial CF titres (titres greater than or equal to 64) also showed annual variation. In general, under 1% of sera contained chlamydial CF antibodies in high titre, but in 1979 and 1984, distinct peaks occurred when 1.3% and 1.4% of sera, respectively, had titres greater than or equal to 64. The age-related antibody positivity rate showed a decline during early infancy, an increase in childhood and adolescence, and a stable level in adulthood when approximately 20% of the sera contained antibodies. The chlamydial antigen used in this survey was genus-specific, i.e. it detects antibodies against all chlamydial species. Epidemiological data support the hypothesis that infections due to a novel chlamydial species, TWAR chlamydia, are the most likely explanation for the relatively frequent occurrence of chlamydial CF antibodies and for the variation in CF antibody prevalence.

Production of polyclonal antisera against cytomegalovirus and varicella-zoster virus by use of affinity-purified viral antigens.

Specific animal antisera to cytomegalovirus (CMV) and varicella-zoster virus (VZV), devoid of antibodies to host cell components, have been difficult to prepare because of the cell-associated nature of these viruses. A simple method for the purification of CMV and VZV antigens is described in this paper. The viral antigens were purified from commercially available crude antigens by affinity chromatography with human antibodies against CMV and VZV. Rabbits were immunized with the purified antigens. The produced antisera were specific for the respective viruses and did not contain antibodies to host cell components, as determined by immunofluorescence microscopy and enzyme-immunoassay. The antisera have been used for direct detection of viral antigens in clinical specimens and for identification of cytopathic effect in cell cultures by immunofluorescence microscopy. The CMV antiserum could also be used for the early detection of CMV in cell cultures inoculated with patient specimens, but it was less sensitive than a monoclonal antibody to the early antigen of CMV.

Diagnosis of cytomegalovirus infection by detection of the early antigen of cytomegalovirus in cell cultures.

Conventional virus isolation and detection of cytomegalovirus (CMV) early antigen by immunofluorescence staining of cultured cells were compared in the diagnosis of CMV infection from urine specimens. By virus isolation, 33 specimens out of 333 studied were positive, and the mean length of culturing time for a positive result was 23 days (range from 6 to 45 days). By early antigen detection, 35 specimens were positive after 20 hours in culture, but the number of positive findings increased to as high as 49 after 7 days in culture. It is recommended that, in addition to the early antigen staining after one day in culture, cells should also be stained after one week in culture, because the sensitivity is essentially improved by extended culturing time.

Inactivation of human immunodeficiency virus in serum specimens as a safety measure for diagnostic immunoassays.

Since the human immunodeficiency virus (HIV) may be transmitted accidentally to laboratory personnel analyzing patient sera, the efficiency of a non-ionic detergent, Triton X-100, in inactivation of HIV in human serum as a safety measure was studied. Semliki Forest virus, an enveloped toga virus, was used as a model virus to create optimal treatment conditions. In the presence of 50% serum, complete inactivation (i.e. no residual virus detected, greater than 7 log reduction of virus titre) was achieved by incubation with 0.2% Triton X-100 for 1 h at 37 degrees C. Under these conditions HIV was also completely inactivated (i.e. no residual infectious virus detected, greater than or equal to 5 log reduction of virus titre). Both treated and untreated serum specimens were also tested with several enzyme immunoassays used in virological laboratories to determine whether the inactivation treatment interfered with the assays. The treated specimens, further diluted as recommended for each assay, were subjected to 15 enzyme immunoassays for microbial antibodies and antigens (HIV IgG, hepatitis A IgG and IgM, hepatitis B s, c, and e antigens and antibodies, cytomegalovirus IgG, mumps virus IgG, poliovirus IgG, rubellavirus IgM, toxoplasma IgG, and chlamydia IgG). Clearly decreased sensitivity was found only with two hepatitis B tests (e antigen and antibody to the surface antigen). It is concluded that safe inactivation of HIV in serum is achieved by 0.2% Triton X-100, but the treatment may decrease the sensitivity of some tests in which low specimen dilution is used.

Rubella immunity and morbidity: effects of vaccination in Finland.

The occurrence of rubella antibodies and frequency of virologically proven rubella infections in different age groups were analyzed in a large serum material (about 60,000 sera) collected both before and after the start of nationwide vaccination of children against measles, mumps and rubella in Finland in 1982. The combined live vaccine significantly raised the rubella immunity of children and shifted rubella infections to older ages. In 1986, 91-98% immunity was found in the 2-10-year-old children so far covered by the vaccination programme; no rubella cases were diagnosed in this age group. We also demonstrated that another rubella vaccine given to about 60% of 13-year-old girls since 1975 both raised the immunity and reduced the occurrence of rubella in the vaccinated population. It is concluded that the rubella vaccinations, especially the combined vaccine given to small children, are effective, although the total number of reported rubella cases in the whole population did not decrease significantly during the study period.

Proportions of immunoglobulin isotypes in paralytic poliomyelitis and after vaccination.

Immunoglobulin isotype composition of poliovirus antibodies was studied by isotype-specific solid-phase radio-immunoassay (RIA) in four patients with paralytic poliomyelitis, five adults receiving live poliovirus vaccine as a booster immunization, and seven children receiving first doses of inactivated poliovirus vaccine. In paralytic poliomyelitis serum and cerebrospinal fluid (CSF) poliovirus antibodies were mainly of IgG1, IgG3, and IgA isotypes. IgM antibodies were found in sera but not in CSF. Either IgG2 and IgG4 antibodies were undetectable or the titers were low. In adults who had received live trivalent poliovirus vaccine, antibodies against poliovirus type 3 were detected in IgG1 (53% of total antibodies), IgG3 (25%), IgM (9%), IgA (8%), IgG2 (3%), and IgG4 (2%) isotypes. In prevaccination and late postvaccination sera the share of IgG3 antibodies was exceptionally high (35%). In children who received inactivated poliovirus vaccine, antibodies developed in IgG1 (53-61% of total antibodies for poliovirus types 1, 2, and 3), IgG3 (12-21%), and IgM (23-33%) isotypes. Antibody levels in IgG2, IgG4, and IgA isotypes were low and observed only in a few cases. Like other viral antibodies IgG1 and IgG3 isotypes were the major IgG subclasses in poliovirus antibodies.

Preparation of nasopharyngeal secretions for immunofluorescence by one-step centrifugation through Percoll.

A simple method was developed for separation of cells from nasopharyngeal secretion for the diagnosis of respiratory virus infections by immunofluorescence microscopy. The diluted specimen, containing dithiothreitol to break up the mucus, was centrifuged once through a cushion of 20% Percoll (colloidal silica, a density gradient medium), which permitted sedimentation of cells through the cushion, but retained mucus on top of it. The pelleted cells were resuspended, and microscope slides were then prepared by standard techniques. The Percoll centrifugation method was also applicable for sputum and bronchoaveolar lavation specimens. Immunofluorescent antibody staining of nasopharyngeal secretions prepared by the described method was more sensitive than enzyme immunoassay for the detection of respiratory syncytial virus.

Detection of poliovirus antigen by enzyme immunoassay.

A solid-phase enzyme immunoassay (EIA) was developed for the detection of poliovirus antigen. Rabbit and guinea pig antisera for the assay were raised against purified poliovirus type 3/Fin (strain 3/Fin/K) isolated from a fecal specimen from a meningitis patient during an outbreak of poliomyelitis in Finland in 1984. The EIA was highly specific for poliovirus type 3, and it was about 30 times more sensitive for strain 3/Fin/K than for strain 3/Saukett used in the inactivated poliovirus vaccine. The sensitivity of the EIA was 2 to 5 ng of purified strain 3/Fin/K per ml, whereas disrupted viruses and soluble viral proteins were almost undetectable by the assay. Only 5 of 51 (10%) stool specimens containing poliovirus type 3/Fin detected by virus isolation were positive by the EIA. Quantitation by the EIA, using purified poliovirus 3/Fin/K as a standard, revealed that concentrations of poliovirus type 3 in undiluted fecal specimens of patients with natural poliovirus infection were only 50 ng/ml or less. In conclusion, owing to the small amount of poliovirus in feces, the EIA is not suitable for the diagnosis of poliovirus infections directly from clinical specimens, but it can be used to detect, type, and quantitate poliovirus antigen in infected cells.