Philip P. Mortimer

TRANSMISSION OF SERUM PARVOVIRUS-LIKE VIRUS BY CLOTTING-FACTOR CONCENTRATES

The serum parvovirus-like virus (SPLV) is a ubiquitous human virus that suppresses the growth of bone-marrow stem cells in vitro. Antibody to it (anti-SPLV) was found in 28 (97%) of 29 children and young adults with haemophilia treated with clotting-factor concentrates but in only 36% of those who had received multiple blood transfusions and in 20% of age-matched controls. The increased anti-SPLV prevalence in haemophiliacs was significant and was not due to passive acquisition of antibody. Haemophiliacs in a residential school showed seroconversion and rises in anti-SPLV titre following the introduction of concentrate treatment. 10 days after receiving his first dose of factor-VIII concentrate a patient had viraemia and then an anti-SPLV IgM response. These observations show that SPLV is often transmitted in clotting-factor concentrates but not in transfused blood. Whether this transmission has any harmful effect is uncertain.

Risk behaviour and HIV prevalence in international travellers

ObjectiveTo assess risk factors for infection and to determine HIV prevalence in a sample of international travellers. DesignA cross-sectional survey of new patients attending a hospital outpatient clinic, and self-completion of an anonymous questionnaire on sexual behaviour prior to and during travel. Urine samples were tested for the presence of antibodies to HIV. SettingThe Hospital for Tropical Diseases, London, UK. SubjectsAll new patients over a 6-month period. ResultsOf 782 people approached, 757 (97%) agreed to participate: 141 (18.6%) had had new sexual partners during their most recent trip abroad. Almost two-thirds of those having sex abroad did not use condoms on every occasion with a new partner, and 5.7% contracted a sexually transmitted disease (STD) during their most recent trip; 26% of men from World Health Organization Pattern I countries who had new sexual partners abroad paid for sex. Sixteen out of 731 (2.2%) participants were HIV-antibody-positive. HIV positivity was associated with being born in east, central or southern Africa, having symptoms of an STD since arriving in the United Kingdom and being treated for an STD since arrival. ConclusionThe rates of unsafe sex and payment for sex abroad reported by these international travellers indicate the potential for contracting and transmitting STD, including HIV, in both their foreign and domestic sexual partnerships. With the increasing HIV incidence in Asia (the most common destination for UK travellers after sub-Saharan Africa), the number of cases of HIV contracted abroad may rise in the future.

Transmission of Human Parvovirus B19 by Coagulation Factor Concentrates

Abstract. The prevalence of antibody to human parvovirus B19 was determined in 86 children with congenital bleeding disorders. Forty‐seven of 53 boys (89%) receiving non‐heat‐treated factor VIII or prothrombin complex concentrates were anti‐B19 IgG positive compared with 38% of their age‐matched controls and 48% of children treated with cryoprecipitate. Acute B19 virus infection occurred in 2 boys 3–4 weeks after they had received the same batch of commercial factor VIII concentrate. Of 11 susceptible children who had only received heat‐treated National Health Service factor VIII concentrate (8Y), I acquired anti‐B19 IgG. This suggests that 8Y heat‐treated concentrate has a much reduced risk of transmitting B19 virus and, by implication, other less heat‐stable viruses such as human immunodeficiency virus.

Hiv surveillance by testing saliva

Saliva specimens were tested for HIV antibody (anti-HIV) by an immunoglobulin G (IgG) antibody capture radioimmunoassay (GACRIA) and three sensitive commercial assays. In tests on 460 seronegative subjects and 196 seropositive subjects GACRIA was 99.8% specific and 100% sensitive. The Wellcome HIV monoclonal and Abbott recombinant DNA enzyme-linked immunosorbent assays (ELISAs) were also highly specific (99.8%, 100%) but they were less sensitive (90.9%, 82.0%). The Fujirebio particle agglutination assay was sensitive (97.8%) but its specificity was poor (84.1%). In testing saliva specimens from populations with an anti-HIV prevalence greater than 0.5%, sampling by GACRIA alone could provide a good estimate of the true prevalence. For true prevalences less than 0.5% good estimates could only be obtained if positive GACRIA reactions were confirmed by another independent salivary assay. Salivary testing for anti HIV is a convenient and potentially an accurate epidemiological tool.

Preliminary report: Accurate assays for anti-HIV in urine

Untreated urine specimens from 358 patients (344 attending genito-urinary medicine clinics, 14 haemophiliacs) and 353 blood donors were tested blind by a simple IgG-capture particle-adherence test (GACPAT) and a rapid IgG-capture enzyme-linked immunosorbent assay (GACELISA) for antibody to human immunodeficiency virus (anti-HIV). All 158 urine specimens from seropositive subjects were anti-HIV positive by GACPAT and 157 of them (99.4%) were positive by GACELISA. Tests on 553 urine specimens from seronegative subjects gave two repeatable false-positive reactions by GACPAT (0.4%) and none by GACELISA. By means of a modified procedure anti-gp160 was detected by commercial western blot in the urine of 44 of 45 seropositive subjects examined. IgG-capture assays will detect anti-HIV in unconcentrated urine and so allow a diagnosis in circumstances when blood sampling is impracticable.

Can Postexposure Vaccination against Smallpox Succeed

What can be achieved by the vaccination of individuals exposed to smallpox virus after release of the virus by bioterrorists? There exist several past sources of information on postexposure vaccination failures from which it may be inferred that prompt vaccination of contacts (i.e., individuals exposed to smallpox) often prevented smallpox altogether, that revaccination of previously vaccinated individuals at any time during the first week of the incubation period was largely protective, and that revaccination done even as late as the second week of the incubation period attenuated disease and prevented most deaths. Primary vaccination done within 4 days of exposure was also usually protective at least from serious illness. Modern contingency planning against the release of smallpox virus during a bioterrorist attack should therefore include the capacity for prompt tracing and (re)vaccination of all contacts. Because a growing majority of the population has never before been vaccinated against smallpox and, so, may be unreachable within 4 days, anticipatory vaccination of sections of the populations of potential target countries should be considered if the bioterrorist threat intensifies.

The Most Prevalent Hepatitis C Virus Genotypes in England and Wales Are 3a and 1a

Hepatitis C virus (HCV) genotypes were assigned to 567 individuals by restriction fragment length polymorphism analysis of the 5′ noncoding region of the HCV genome following reverse transcription–polymerase chain reaction. The groups of individuals in this study included hemophilia patients, injecting drug users (IDUs), blood donors, antenatal patients, those attending genitourinary medicine (GUM) clinics, and patients with chronic liver disease, all from England and Wales. The majority of HCV infections were types 1a (32%), 1b (15%), or 3a (37%). The genotype distribution in individual groups was similar to the overall genotype distribution except for hemophilia patients, in whom the frequencies were 1a (39%), 1b (23%), and 3a (21%). With the exception of hemophilia patients, subpopulations in England and Wales appear to share common modes of HCV transmission. There is a need for continued surveillance to monitor the spread of possibly more virulent or drug‐resistant HCV genotypes. J. Med. Virol. 58:127–131, 1999.

Detection of antibody to HIV in saliva: a brief review

BACKGROUND The possibility that saliva could be used for HIV screening and diagnosis has been known since 1986. Despite the obvious advantages over venepuncture of ease of collection, safety, compliance and cost, interest in salivary testing has grown relatively slowly. Several studies have demonstrated that salivary anti-HIV testing can be highly accurate, particularly if specimen collection procedure are optimal. OBJECTIVE To review current knowledge about the detection of anti-HIV in oral fluids, with an emphasis on the identification of optimal procedures. STUDY DESIGN In the light of existing published data, the factors leading to accurate salivary diagnosis of HIV infection were identified and reviewed. RESULTS To achieve the best results it is essential to collect oral fluid specimens that are rich in IgG. Most IgG in the oral cavity derives from the crevicular space between the gums and the teeth, and not from salivary glands. Available methods for collecting salivary specimens are discussed. Until these collection methods are fully validated, individual specimens or at least clinical ones found anti-HIV negative should be tested for total IgG before being reported on. There is a lack of proven confirmatory methods for salivary anti-HIV and this problem is reviewed. Salivary anti-HIV testing has been employed mostly for surveillance, but life insurance applicants are increasingly screened in this way and clinical applications are under active consideration. With appropriate safeguards, diagnostic and pre-blood donation salivary testing could be introduced shortly. The necessary technology is also available to develop rapid single-use salivary tests. This would bring anti-HIV testing closer to the patient. CONCLUSIONS Salivary tests for anti-HIV offer advantages of convenience, economy and safety, and are more acceptable to subjects than blood tests. Further evaluation of the collection devices and assays, the introduction of safeguards against inadequate sampling and the development of suitable confirmatory assays are required. When these deficiencies have been met, salivary tests may supersede tests on serum for HIV and also other infections.

National surveillance of HIV-1 subtypes for England and Wales: Design, methods, and initial findings

Summary: The HIV‐1 infections detected in an ongoing national unlinked anonymous HIV surveillance program were subtyped and analyzed according to demographic and risk characteristics. Of the 893 anti‐HIV‐1‐positive specimens allocated to an exposure group, 70% could be subtyped. Almost 25% of infections subtyped were non‐B, mostly subtypes A, C, and D. Non‐B infections were rare in homosexual and bisexual men and in drug injectors. Forty percent of infections in heterosexual men attending genitourinary medicine clinics were non‐B subtypes; of these, 25% were subtype A infections and 59% were subtype C infections. For female clinic attendees, 61% were non‐B subtype infections, of which 48% were subtype A infections and 42% were subtype C infections. Of the clinic attendees born in the United Kingdom and Europe, 14% of the men and 35% of the women were infected with non‐B subtypes. In contrast, 78% of infections in antenatal patients were non‐B subtypes, of which 61% were subtype A and 29% were subtype C. Extrapolation to the estimated 29,700 prevalent adult infections in the United Kingdom indicates that approximately 8,100 (27%) such infections are non‐B subtypes and that these are found almost entirely in heterosexuals. The findings suggest spread of infection of non‐B subtypes to heterosexuals born in the United Kingdom from individuals infected in regions of high prevalence.

The use of saliva for viral diagnosis and screening.

The strength and diversity of antibody responses to infection are the basis for many of the most rapid and sensitive tests in virology, yet the need to obtain the patients consent and co–operation, to collect blood from a vein and to separate the serum before the test often deters investigators, particularly if children are involved or if there is added risk, difficulty or cost in doing the venepuncture.