Respiratory viruses in a hospitalized paediatric population in Edinburgh 1985-1994.

We describe the incidence of respiratory viruses identified in children admitted to an Edinburgh hospital between October 1985 and July 1994. Respiratory syncytial (RS) virus, influenza viruses and parainfluenza viruses showed seasonal activity whereas adenoviruses and rhinoviruses did not. Parainfluenza viruses were the most changeable in their epidemiological behaviour and RS virus the least.

Mycoplasma pneumoniae infection: early diagnosis by detection of specific IgM by immunofluorescence.

An indirect immunofluorescent antibody test for early detection of IgM antibodies to Mycoplasma pneumoniae is described, using sera from which IgG antibodies have been removed. The results over a five-year period were studied and compared with complement fixation testing and isolation of the organism. During the epidemic season of November 1990 to April 1991, the immunofluorescent IgM test was used as a first-line test on specimens taken both early and late in the illness to provide a simple, inexpensive and clinically useful test, with 151 positive results being obtained from 886 sera tested.

Use of recombinant human parvovirus B19 antigens in serological assays.

AIMS--To compare the sensitivity, specificity, and practicality of recombinant proteins in serological tests for the detection of human parvovirus B19 IgG and IgM. METHODS--Indirect enzyme linked immunosorbent assays using B19 structural proteins expressed in Escherichia coli were developed for the detection of B19 specific IgG and IgM (rELISA-G and rELISA-M). Cells infected with baculovirus expressing B19 structural proteins were also used in an indirect immunofluorescence assay for IgG and IgM antibodies (IFA-G and IFA-M). Antibody capture radioimmunoassays for IgG and IgM (GACRIA and MACRIA) were used as comparative assays. RESULTS--Twenty nine pools of intravenous immunoglobulin were clearly positive for B19 IgG by rELISA-G and contained low IgG titres by GACRIA. From 113 samples tested by all methods, sensitivities of 92% (77/84) and 97% (68/70) were obtained for ELISA and immunofluorescence, respectively, when compared with GACRIA. One hundred and sixteen samples from patients presenting with rash or arthralgia were compared by MACRIA, rELISA-M, and IFA-M. Sensitivities of both recombinant tests were more than 95%. Despite pretreatment to remove IgG or rheumatoid factor, false positive results were a problem in the rELISA-M but were not seen with the IFA-M. CONCLUSIONS--The limited supply of native antigen has severely restricted the wide application of serology for parvovirus B19. The use of recombinant antigens permitted the introduction of local screening tests which had many advantages, including quicker results and relief of the burden on the Reference Laboratory. The use of rELISA-M for sensitivity and IFA-M for specificity and confirmation proved a useful and practical combination for diagnosis of recent infection with B19, and rELISA-G allowed the immune response to be determined in selected populations.

Detection of respiratory syncytial virus in acute bronchiolitis in infants.

Direct detection of respiratory syncytial (RS) virus antigen in nasopharyngeal secretions (NPS) provides the most rapid diagnostic test for RS infection, but more sensitive methods might be more beneficial in the study of virus shedding. RS virus RNA was extracted from cells stored at -70 degrees C either in suspension with added RNAse inhibitor or as a pellet without inhibitor. The RNA was reverse transcribed, the resultant cDNA amplified by the polymerase chain reaction and detected by ethidium bromide staining after electrophoresis through agarose gel (RT-PCR). Of 217 specimens tested, 106 were positive by antigen detection, 99 by RT-PCR, and 92 by virus isolation. In a series of 97 sequential NPS specimens from 15 infants in whom RS virus induced bronchiolitis was confirmed, antigen detection proved most sensitive in the first week after onset and RT-PCR detected most positive specimens in the second week. Storage of the cells as a pellet proved more satisfactory than storage as a suspension. A further round of amplification using nested primers increased the number of positive results obtained by RT-PCR. The sensitivity of antigen detection using directly labelled monoclonal antibody to RS virus was slightly higher than that of RT-PCR, but the specificity was slightly lower.

How many bloods will a 'HIVCHEK' check? Multiple tests for HIV antibody for a single screening kit.

Detection of HIV infection in blood donors or populations is usually by testing sera for antibodies to HIV-1 and HIV-2. Screening tests are now highly sensitive and specific, but still expensive and scarce in Africa. We tested the commercially available kits 'HIVCHEK 1 + 2' in two field laboratories, on specimens from blood donors and antenatal women in rural Zaire. We describe a method of using one test kit for up to five serum samples, saving money and time. In 491 antenatal mothers in Eastern Zaire, among whom the HIV seroprevalence was 3.3%, we compared 'HIVCHEK' results with results obtained by ELISA and Western blot. The 'HIVCHEK' multiple-sample method had a sensitivity of 82% and a specificity of 99.6%. In an area with an HIV seroprevalence of < 4%, using 'HIVCHEK' by the multiple sample method would lead to a saving of about 2,400 pounds for every 1000 individuals tested.

Prevalence of HIV among childbearing women and women having termination of pregnancy: multidisciplinary steering group study.

OBJECTIVE: To determine the prevalence of HIV among pregnant women, in particular those whose behaviour or that of their partners put them at "low risk" of infection. DESIGN: Voluntary named or anonymous HIV testing of pregnant women during 21 months (November 1988 to July 1990). SUBJECTS AND SETTING: All women who planned to continue their pregnancy and attended clinics serving the antenatal populations of Edinburgh and Dundee. All women admitted for termination of pregnancy to gynaecology wards serving the pregnant populations of Dundee and outlying rural areas. MAIN OUTCOME MEASURES: Period prevalence of HIV antibody positivity. RESULTS: 91% of antenatal clinic attenders and 97% of women having termination of pregnancy agreed to HIV testing on a named or anonymous basis. HIV period prevalences for antenatal clinic attenders and women having termination of pregnancy tested in Dundee were 0.13% and 0.85% respectively, and for antenatal clinic attenders tested in Edinburgh 0.26%. For those at "low risk" rates for antenatal clinic attenders and women having termination of pregnancy in Dundee were 0.11% and 0.13%, and for antenatal clinic attenders in Edinburgh 0.02%. In Dundee HIV prevalence among women having a termination of pregnancy (0.85%) was significantly greater than that among antenatal clinic attenders (0.13%). CONCLUSIONS: HIV infection is undoubtedly occurring among women at "low risk," and it is clear that a policy of selective testing of those at only "high risk" is inadequate for pregnant women living in areas of high prevalence such as Edinburgh and Dundee. Moreover, when studying pregnant populations in such areas there is the need to include those having a termination of pregnancy.

PIP: This study sought to determine the prevalence of HIV among pregnant women, in particular those whose behavior or that of their partners put them at low-risk for infection. This was a voluntary named or anonymous HIV testing of pregnant women between November 1988-July 1990 among all women who planned to continue their pregnancies and attended clinics serving antenatal populations in Edinburgh and Dundee and those women admitted for termination of pregnancy to gynecology wards serving the pregnant populations of Dundee and outlying rural areas. 91% of the antenatal clinic attenders and 97% of women having pregnancy termination agreed to HIV testing on either a named or anonymous basis. HIV period prevalences for antenatal clinic attenders and women having pregnancy termination tested in Dundee were 0.13% and 0.85% respectively, and for antenatal clinic attenders tested in Edinburgh 0.26%. For those at low-risk, the rates for antenatal clinic attenders and women having pregnancy termination in Dundee were 0.11% and 0.13%, and for antenatal clinic attenders in Edinburgh 0.02%. In Dundee, HIV prevalence among women having a termination of pregnancy (0.95%) was significantly greater than that among antenatal clinic attenders (0.13%). HIV infection is undoubtedly occurring among low-risk women and it is clear that a policy of selective testing of those only at high-risk is inadequate for pregnant women living in areas of high prevalence such as Edinburgh and Dundee. Moreover, when studying pregnant populations in such areas, there is a need to include those undergoing pregnancy termination.

Association between secretor status and respiratory viral illness.

OBJECTIVE: To determine whether non-secretion of blood group antigens is associated with respiratory virus diseases. DESIGN: Study of secretor status in patients with respiratory virus diseases determined by an enzyme linked immunosorbent assay (ELISA) developed to identify Lewis (Le) blood group antigen phenotypes (Le(a) non-secretor; Le(b) secretor). SUBJECTS: Patients aged 1 month to 90 years in hospital with respiratory virus diseases (584 nasal specimens). MAIN OUTCOME MEASURES: Criteria for validation of ELISA (congruence between results on ELISA testing of 1155 saliva samples from a previous study and previously established results on haemagglutination inhibition (HAI) testing, proportions of Le(a), Le(b), and Le- phenotypes in 872 samples of nasal washings from a previous study compared with the normal population). Secretor status of patients determined by ELISA and viruses isolated. RESULTS: Agreement between HAI and ELISA for 1155 saliva samples was 97%. Lewis antigens were detected by ELISA in 854 (97.9%) of nasal washings (Le(a) 233 (26.7%), Le(b) 621 (71.2%), and Le- 18 (2.1%)) in proportions predicted for a northern European population. Secretors were significantly overrepresented among patients from whom influenza viruses A and B (55/64, 86%; p less than 0.025), rhinoviruses (63/72, 88%; p less than 0.01), respiratory syncytial virus (97/109, 89%; p less than 0.0005), and echoviruses (44/44, p less than 0.0005) had been isolated compared with the distribution of secretors in the local population. CONCLUSION: Secretion of blood group antigens is associated with respiratory virus diseases.

Detection of respiratory syncytial virus antigen and nucleic acid in clinical specimens using synthetic oligonucleotides.

Rapid detection of respiratory syncytial (RS) virus in nasopharyngeal secretions (NPS) was carried out on cytospin cell preparations using a directly labelled monoclonal antiserum to RS virus to detect viral antigen and digoxigenin-labelled synthetic oligonucleotides to detect viral nucleic acid. Sequences of 27 and 30 bases in length from within the fusion protein and nucleocapsid genes respectively were selected for use as probes. The oligonucleotide in situ hybridization test was easy to perform and could be completed within 24 hours, but antigen detection was much more rapid and more sensitive. During 1989-1990, more positive results were obtained by antigen detection (193) than by isolation (185), but of 43 confirmed RS-virus-positive specimens, only 21 (49%) were detected by ISH. Antigen detection remains the most suitable single method of rapid detection of RS virus for a diagnostic laboratory.

Rapid detection of respiratory syncytial virus antigens in nasopharyngeal secretions.

The combined use of fluorescein-labelled monoclonal antibody and a cytocentrifuge for preparation of cell spots greatly reduced the time for rapid diagnosis, and improved the sensitivity and ease of detection of respiratory syncytial (RS) virus antigen in specimens of nasopharyngeal secretions.

Vertical transmission of HIV: a prospective study.

Forty nine infants of HIV seropositive women were followed up for a median of 24 months, together with 24 controls. The infection status of 11 index children under 18 months of age was indeterminate; 34 were presumed uninfected while four showed clinical and laboratory evidence of HIV disease. Based on current definitions of HIV infection and excluding children under 18 months old as well as those who had not been studied from birth, two out of 28 children were infected. The estimated rate of maternofetal transmission was therefore 7.1%. In children with proved infection, sequential laboratory data showed that hypergammaglobulinaemia was noted as early as 6 months and often predated clinical signs. This observation, in the presence of non-specific clinical findings, was helpful in alerting the paediatrician to a diagnosis of HIV infection.

The management of children born to human immunodeficiency virus seropositive women.

Increasing numbers of children born to human immunodeficiency virus (HIV) antibody-positive women are being identified, but guidelines as to their management are lacking. We have therefore established a paediatric counselling and screening clinic for managing such children in Edinburgh. During a period of 3 years, 49 infants and children of 43 HIV seropositive women have been seen. After a median follow-up period of 23 months, four children were found to have clinical evidence of HIV disease which was non-specific and could have been missed had they not been regularly monitored. Thus, close surveillance of infants born to seropositive women is important. Identifying a single clinic where this is done has allowed experience to accumulate on issues beyond the medical management of these infants as well as contributing to the clinical care of infants with symptoms. Based on this experience, we have developed guidelines for managing children born to HIV antibody-positive women.

Does infection with HIV affect the outcome of pregnancy?

PIP: Details are presented on the outcome of pregnancy in a group of Edinburgh women identified as positive for antibodies to HIV and in women who had a history of drug abuse or a partner known to be seropositive but who were themselves negative for HIV antibody. Pregnant women who had been tested for HIV up to June 1987 were identified. HIV state was known for 205 pregnant women. Most cases were determined during pregnancy, but in 23 (9 seropositive patients) it was determined retrospectively. Seropositivity was only found in women who had been intravenous drug users or whose partner was known seropositive. Of 50 women who were seropositive, 46 were intravenous drug users and 4 had seropositive partners. In 64 cases who were seronegative, 45 had used intravenous drugs since 1983, and 19 had a seropositive partner. These women tended to be young, unmarried, and smoked heavily. They usually lived in areas of Edinburgh with multiple deprivation. Both they and their partners were usually unemployed. In the seropositive group, spontaneous abortion showed an apparent increase, but this may be due to differences in ascertainment as the incidence in the seronegative group was low. Premature delivery, intrauterine growth retardation, and low birth weight were common compared with the total population, but seropositive and seronegative women did not differ from each other in these variables. Compared with rates in the total population of Edinburgh, the rates of prematurity and intrauterine growth retardation were increased more than 2-fold and the rate of low birthweight babies was increased nearly 4-fold, though the 1 twin pregnancy contributed to this. Adverse outcome was equally distributed between the seropositive and seronegative women, and there was no suggestion that infection with HIV itself had any effect. Although no evidence from this study shows that infection with HIV per se affects the outcome of pregnancy, none of these women showed symptomatic illness.^ieng

Heterosexual spread of human immunodeficiency virus in Edinburgh.

Heterosexual transmission of human immunodeficiency virus (HIV) was investigated in 123 subjects with no apparent risk factor for infection other than having had heterosexual intercourse with a person who was either infected with HIV or at high risk of being infected with it. Seven subjects were found to be infected with the virus. Risk factors for transmission included being the regular sexual partner of an abuser of intravenous drugs and having a sexual relationship of more than 18 months' duration. Anal intercourse was not a risk factor in the three subjects who admitted to it. There were 41 regular partnerships with abusers of intravenous drugs in which the antibody state and history were fully known for both partners. In these partnerships male to female transmission of the virus occurred in five out of 34 (15%) and female to male in one out of seven. In 30 couples in whom one partner was known to be positive for HIV and an abuser of intravenous drugs four female partners were found to be seropositive at first testing, but there were no new positive results on subsequent serial testing. In six of these 30 couples both partners abused intravenous drugs but the partner who was negative for HIV remained so. Few of the partnerships always practised safe sexual techniques, even after a partner was known to be positive for HIV. Heterosexual transmission of HIV occurred but was incomplete and may be related to the timing of the relationship with the infection.

Human immunodeficiency virus and drug misuse: the Edinburgh experience.

During 1985 many drug abusers who lived in Edinburgh were found to be infected with the human immunodeficiency virus (HIV). As a result an alternative counselling and screening clinic for testing for antibodies to HIV was established for use by drug abusers. Four hundred and forty one patients were counselled in the first year, and over 60% were either drug abusers or their sexual contacts. One hundred and fourteen (26%) patients were positive for HIV antibody, and 100 (88%) of these were current or former drug abusers. The HIV seropositivity rate in drug abusers was 52% but was only 7% in their sexual contacts. Services were provided for these people as well as counselling before and after the test. The cost of this counselling service for the first year was 27,000 pounds or 61.22 pounds per patient. The unexpected mobility of 23% of the Edinburgh drug abusers, particularly to other areas of Britain, suggests that similar services need to be set up elsewhere.

Respiratory viruses in children admitted to hospital in Edinburgh 1972-1985.

The temporal incidence of respiratory viruses identified in children admitted to an Edinburgh hospital over a period of 14 years, 1972-1985, is described, Respiratory syncytial (RS) virus was identified most often, usually (but not in 1979 and 1985) with single peaks of activity in the winter months. Influenza virus infections were seen in the winter and spring but we failed to find evidence of interference between RS and influenza virus. Of the viruses studied, the parainfluenza viruses were the least predictable in their epidemiological behaviour. The results of this study are compared with those of others and the role of certain aspects of the weather is considered.

Rapid diagnosis of herpes simplex virus infections in conventional and shell vial cell cultures using monoclonal antibodies.

One hundred specimens for herpes simplex virus (HSV) isolation were tested in parallel by conventional and by centrifugation-enhanced cell culture, followed by identification using monoclonal antibodies to HSV-1 and HSV-2. Sensitivity was comparable by the two methods; conventional culture was only marginally slower and was easier to fit into the routine of a busy laboratory. It is, therefore, advocated for HSV detection in clinical specimens.

A comparison of the reactivity and immunogenicity of RA 27/3 strain rubella vaccine prepared in WI-38 or MRC5 human diploid cells.

The immunogenicity and clinical reactivity of rubella vaccine derived from WI-38 or MRC5 human diploid cells was compared in 125 seronegative adolescent females. Seroconversion rates, assessed by single radial haemolysis testing of paired pre- and post-vaccination samples exceeded 98% (56/57 and 68/68 vaccinees, respectively) for both vaccines. Quantitative assessment of rubella-specific antibodies in 53 post-vaccination sera by an ELISA technique also failed to reveal any difference in immunogenicity between the vaccines. Assessable calendar records documenting the occurrence of local and systemic signs and symptoms in the four weeks following vaccination were returned by 106 subjects. No important statistically significant difference in parameters of clinical reactivity between the vaccine groups was observed although the incidence of pain at the injection site was found to be significantly higher for vaccinees receiving WI-38 derived vaccine.