UK measles outbreak in non-immune anthroposophic communities: the implications for the elimination of measles from Europe

We describe the epidemiology of the first nationwide outbreak of measles infection in the UK since the implementation of a mass vaccination campaign. Notifications of infectious diseases, interview and postal questionnaire identified 293 clinical cases, 138 of which were confirmed by salivary IgM, measles virus isolation and PCR. Twelve were epidemiologically linked to confirmed cases. The outbreak began in London, after contact with measles infection probably imported from Italy. Measles genotyping determined by sequence analysis confirmed spread to other unimmunized anthroposophic communities in the north, south west and south coast of England. Only two cases had been vaccinated against measles infection, and 90% of cases were aged under 15 years. Measles virus can selectively target non-immune groups in countries with high vaccine uptake and broader herd immunity. Without harmonization of vaccination policies and uniform high coverage across Europe, the importation and spread of measles virus amongst non-immune groups may prevent the elimination of measles.

Prenatal diagnosis of congenital Wilms' tumor (nephroblastoma) presenting as fetal hydrops

We describe a case of congenital nephroblastoma (Wilms' tumor) presenting at 28 weeks of gestation with fetal hydrops and polyhydramnios. Prenatal diagnosis was made by biopsy. An emergency Cesarean section was performed due to deterioration in the cardiotocograph. A post-mortem examination confirmed the diagnosis of congenital nephroblastoma.

Protein phosphatase-1 regulation in the induction of long-term potentiation: heterogeneous molecular mechanisms

Protein phosphatase inhibitor-1 (I-1) has been proposed as a regulatory element in the signal transduction cascade that couples postsynaptic calcium influx to long-term changes in synaptic strength. We have evaluated this model using mice lacking I-1. Recordings made in slices prepared from mutant animals and also in anesthetized mutant animals indicated that long-term potentiation (LTP) is deficient at perforant path-dentate granule cell synapses. In vitro, this deficit was restricted to synapses of the lateral perforant path. LTP at Schaffer collateral-CA1 pyramidal cell synapses remained normal. Thus, protein phosphatase-1-mediated regulation of NMDA receptor-dependent synaptic plasticity involves heterogeneous molecular mechanisms, in both different dendritic subregions and different neuronal subtypes. Examination of the performance of I-1 mutants in spatial learning tests indicated that intact LTP at lateral perforant path-granule cell synapses is either redundant or is not involved in this form of learning.

Phylogeography of mitochondrial DNA variation in brown bears and polar bears

We analyzed 286 nucleotides of the middle portion of the mitochondrial cytochrome b gene of 61 brown bears from three locations in Alaska and 55 polar bears from Arctic Canada and Arctic Siberia to test our earlier observations of paraphyly between polar bears and brown bears as well as to test the extreme uniqueness of mitochondrial DNA types of brown bears on Admiralty, Baranof, and Chichagof (ABC) islands of southeastern Alaska. We also investigated the phylogeography of brown bears of Alaska's Kenai Peninsula in relation to other Alaskan brown bears because the former are being threatened by increased human development. We predicted that: (1) mtDNA paraphyly between brown bears and polar bears would be upheld, (2) the mtDNA uniqueness of brown bears of the ABC islands would be upheld, and (3) brown bears of the Kenai Peninsula would belong to either clade II or clade III of brown bears of our earlier studies of mtDNA. All of our predictions were upheld through the analysis of these additional samples.

Active surveillance of hepatitis C infection in the UK and Ireland

AIM

To investigate the prevalence, distribution, and clinical details of paediatric hepatitis C virus (HCV) infection in the UK and Ireland.

METHODS

Active monthly surveillance questionnaire study coordinated through the British Paediatric Surveillance Unit, to all consultant paediatricians in 1997 and 1998.

RESULTS

A total of 182 HCV infected children were reported from 54 centres and by paediatricians from eight different specialties. In 40 children HCV was acquired through mother to child transmission (MTC children); 142 were infected by contaminated blood products (n = 134), organ transplantation (n = 2), needles (n = 4), or unknown risk factor (n = 2). Intravenous drug use was the risk factor for 35 mothers of MTC children. Twelve children were coinfected with HIV and four with HBV. Recent serum aspartate aminotransferase or alanine aminotransferase values were at least twofold greater than the upper limit of normal in 24 of 152 children; this occurred in five of 11 HIV coinfected children. Liver histology, available in 53 children, showed normal (7%), mild (74%), moderate (17%), or severe (2%) hepatitis. Twenty eight children had received therapy with interferon alfa.

CONCLUSION

Most current paediatric HCV infection in UK and Ireland has been acquired from contaminated blood products, and most children are asymptomatic. There is a need for multicentre trials to inform clinical practice and development of good practice guidelines in this area. Long term follow up of this cohort of HCV infected children is planned to help determine the natural history over the long term of HCV acquired during infancy and childhood.

Identification of P gene mutations in individuals with oculocutaneous albinism in sub-Saharan Africa

Oculocutaneous albinism (OCA) is an inherited disorder resulting in hypopigmentation of the skin, hair, and eyes. OCA type 2 (tyrosinase-positive) is the most common recessively inherited disorder among southern African Blacks. OCA2 is also seen in southern African Caucasoids, but is less frequent. The gene responsible for this type of albinism, P, is the human homolog of the mouse pink-eyed dilution gene. Mutations at this locus are also responsible for the milder hypopigmentation phenotype seen in individuals with brown oculocutaneous albinism (BOCA). A common African P mutation was identified in Black OCA2 individuals, and has since been shown to occur in Black individuals with brown OCA as well. This mutation is a 2.7 kb interstitial deletion. In this study, we undertook to screen the coding region of the P gene for mutations in the non-2.7 kb deletion alleles of OCA2 patients who did not carry the deletion allele in either one or both of their P genes. We identified four mutations (A334V, 614delA, 683insG [corrected], 727insG) in a group of 39 unrelated Black OCA2 patients with a total of 52 non-2.7 kb deletion OCA2 genes. When taking all OCA2 cases into consideration, including those homozygous for the 2.7 kb deletion mutation, these account for a further 1.7% of OCA2 mutations in southern African Blacks, increasing the overall mutation detection rate to 78.7%. Three mutations (E678K, L688F, I370T) were identified in a group of 15 Black patients with an initially unclassified type of OCA and another three mutations (IVS 14-2 (a-->g), V350M, P743L) were identified in nine Caucasoid OCA patients. Relatively few mutations, all with low frequency, were identified in the non-2.7 kb deletion OCA genes. We propose that other mutations may lie either within intronic sequence or within the promoter region of the gene.

Nontoxigenic corynebacterium diphtheriae: an emerging pathogen in England and Wales?

Confirmed isolates of nontoxigenic Corynebacterium diphtheriae in England and Wales increased substantially from 1986 to 1994. Ribotyping of 121 isolates confirmed in 1995 showed that 90 were of a single strain isolated exclusively from the throat; none had previously been identified in toxigenic strains from U.K. or non-U.K. residents. The upward trend in nontoxigenic C. diphtheriae probably represented increased ascertainment, although dissemination of a particular strain or clone may have been a factor.

Clinical features, laboratory findings and management of meningococcal meningitis in England and Wales: report of a 1997 survey. Meningococcal meningitis: 1997 survey report

OBJECTIVES

To describe the epidemiological, clinical and laboratory features of meningococcal meningitis and the effects of antibiotics on laboratory investigations under current clinical practices in England and Wales.

METHODS

Using a telephone questionnaire, information was gathered on 103 cases with a clinical diagnosis of meningococcal meningitis. Included were cases with samples submitted to the Public Health Laboratory Service (PHLS), Meningococcal Reference Unit (MRU) over a 5-month period in 1997. Tests included microscopic examination, latex agglutination and culture for Neisseria meningitidis, and at MRU confirmation of identification and characterization of isolates and meningococcal polymerase chain reaction (PCR) analysis on blood and cerebrospinal fluids (CSF).

RESULTS

Clinically 45% of the cases had predominantly meningitis and 55% had septicaemia and meningitis. Only 29% of the cases received pre-admission benzylpenicillin, and 66% were given antibiotics within an hour of hospital attendance. Microbiological confirmation was achieved in 97 cases, 46 (44%) by traditional tests and 92 (89%) by PCR assay, including some with both. The blood culture positive rate was 23 (22%), but in predominant meningitis the rate was only 10% (5/46). PCR was the sole method of confirmation in 48 cases. Seventy percent of the plasma samples referred were reactive by PCR assay, but all samples taken more than 24 h after hospital antibiotics were non-reactive. PCR-based techniques increased the overall number of cases with a serogroup identified by 44%. Lumbar punctures were performed in 73 of the cases and microbiological confirmation was achieved in 67 (92%) of these cases, compared to 26/30 without lumbar puncture (LP). Eighty-nine percent of the CSF samples referred were reactive by PCR; 50% of the CSF samples taken more than 24 h after hospital antibiotics were reactive, whilst none were positive by culture or microscopy.

CONCLUSION

Due to variable clinical manifestations, early diagnosis and treatment was difficult. Laboratory confirmation has been improved by the introduction of PCR-based techniques. Meningococcal DNA was detected by molecular methods in CSF samples taken up to 72 h after commencement of antibiotics. During this period patients could be stabilized and the chances of complications attendant upon early LP reduced. In addition to providing accurate epidemiological information, confirming the diagnosis may alter the extent and length of follow-up.

Epidemiology of group a rotaviruses surveillance and burden of disease studies

Human infection has been reported with groups A, B, and C rotaviruses (RVs). Of these, Group A RVs are the most important, being a major cause of severe gastroenteritis (GE). Each year, Group A RVs are estimated to cause approx 870,000 deaths worldwide in children less than 5 years (yr) of age, mostly in developing countries (1). This chapter will describe the epidemiological features of Group A RV infections, and will critically review the current surveillance strategies used to define the burden of disease.

Invasive meningococcal disease among university undergraduates: association with universities providing relatively large amounts of catered hall accommodation

The incidence of invasive meningococcal disease (IMD) among UK university students and non-students of similar age was investigated. In addition, we sought to identify structural risk factors associated with high rates of IMD in individual universities. Cases were ascertained via Consultants in Communicable Disease Control (or equivalent officers) between September 1994 and March 1997. Data on individual universities were obtained from university accommodation officers. University students had an increased annual rate of invasive meningococcal disease (13.2/10(5), 95% CI 11.2-15.2) compared with non-students of similar age in the same health districts (5.5/10(5), CI 4.7-6.4) and in those health districts without universities (3.7/10(5), CI 2.9-4.4). This trend was highly significant. Regression analysis demonstrated catered hall accommodation to be the main structural risk factor. Higher rates of disease were observed at universities providing catered hall places for > 10% of their student population (15.3/10(5), CI 11.8-18;8) compared with those providing places for < 10% of students (5.9/10(5), CI 4.1-7.7). The majority of IMD amongst students was caused by serogroup B organisms. University students in the UK are at increased risk of IMD compared with non-students of a similar age. The incidence of IMD tends to be greatest at universities with a high provision of catered hall accommodation.

High polymorphism at the human melanocortin 1 receptor locus

Variation in human skin/hair pigmentation is due to varied amounts of eumelanin (brown/black melanins) and phaeomelanin (red/yellow melanins) produced by the melanocytes. The melanocortin 1 receptor (MC1R) is a regulator of eu- and phaeomelanin production in the melanocytes, and MC1R mutations causing coat color changes are known in many mammals. We have sequenced the MC1R gene in 121 individuals sampled from world populations with an emphasis on Asian populations. We found variation at five nonsynonymous sites (resulting in the variants Arg67Gln, Asp84Glu, Val92Met, Arg151Cys, and Arg163Gln), but at only one synonymous site (A942G). Interestingly, the human consensus protein sequence is observed in all 25 African individuals studied, but at lower frequencies in the other populations examined, especially in East and Southeast Asians. The Arg163Gln variant is absent in the Africans studied, almost absent in Europeans, and at a low frequency (7%) in Indians, but is at an exceptionally high frequency (70%) in East and Southeast Asians. The MC1R gene in common and pygmy chimpanzees, gorilla, orangutan, and baboon was sequenced to study the evolution of MC1R. The ancestral human MC1R sequence is identical to the human consensus protein sequence, while MC1R varies considerably among higher primates. A comparison of the rates of substitution in genes in the melanocortin receptor family indicates that MC1R has evolved the fastest. In addition, the nucleotide diversity at the MC1R locus is shown to be several times higher than the average nucleotide diversity in human populations, possibly due to diversifying selection.

Cystic fibrosis carrier frequencies in populations of African origin

Cystic fibrosis (CF) is a common autosomal recessive disorder in populations of European descent. However, very little is known about CF in populations of African origin among whom it has been believed to be extremely rare. The aim of this study was to determine if this is the case or whether it is under-reported. A CFTR mutation, 3120+1G-->A, which was first reported in three African-American CF patients, has been shown to account for 9-14% of African-American CF chromosomes. It has also been found in 4/6 CF chromosomes in South African blacks and one CF chromosome of Cameroonian origin. In order to determine the carrier frequency of the 3120+1G-->A mutation in Africa, 1360 unrelated, healthy subjects were screened. Nine carriers were identified. In addition, two out of five black CF patients with positive sweat tests were found to be heterozygous for the 3120+1G-->A mutation and two out of another four black patients with symptoms suggestive of CF, but unconfirmed by sweat tests, were heterozygous for the D1270N mutation. A further three CFTR mutations, A559T, S1255X, and 444delA, which had been found in African-American CF patients, were not identified in the patients or in over 373 healthy subjects tested. The 3120+1G-->A mutation has a carrier frequency of 1 in 91 (8/728) in South African blacks with a 95% confidence interval of 1 in 46 to 1 in 197. Since this mutation accounts for between 15% and 65% of CF chromosomes in South African blacks, a corrected CF carrier frequency would be between 1 in 14 and 1 in 59. Hence, the incidence of CF would be predicted to be between 1 in 784 and 1 in 13924 births in this population. There are several possible reasons why these people are not being detected. Some of these are misdiagnosis as chronic pulmonary infection, malnutrition, tuberculosis, infantile diarrhoea, failure to thrive, or a high infant mortality rate.

An estimate of the proportion of diarrhoeal disease episodes seen by general practitioners attributable to rotavirus in children under 5 y of age in England and Wales

Mean weekly incidence rates for a 4-week period of new episodes of infectious intestinal disease (IID) and laboratory reports of faecal isolations in children under 5 y of age presenting in general practice were used to estimate the incidence of IID due to rotavirus infection in England and Wales. Between January 1992 and December 1996, a total of 92452 new episodes of IID were seen at sentinel general practices and reported to the Royal College of General Practitioners (RCGP) Research Unit in Birmingham, UK. Of these 32% (29592) were in children under 5 y of age. During the same period the Communicable Disease Surveillance Centre (CDSC) in London, UK received 159532 reports of faecal identifications in children under 5 y of age; 69219 (43%) of these were due to rotavirus. By modelling RCGP data and laboratory reports, the proportion of episodes attributable to rotavirus infection was estimated to be 29% (95% CI: 24% to 34%). By extrapolation of RCGP data it was estimated that rotavirus accounted for 762000 of new episodes of IID nationally in children under 5 y of age between January 1992 and December 1996. Implementation of a rotavirus vaccination programme could substantially reduce the incidence of childhood diarrhoea.

Control of hepatitis B in the United Kingdom

Control of hepatitis B in the UK is based upon selective vaccination of persons in high-risk groups. To assess the likely cost-effectiveness of changes to this policy, information on the current burden of HBV infection in the UK is required. Laboratory reports of acute hepatitis B suggest that the vast majority of new hepatitis B infections acquired in the UK occur in adults, even after adjustment for unapparent infection. In childhood, perinatal transmission remains the most significant known risk factor. Universal antenatal screening has the potential to prevent perinatal infections in UK births and a substantial proportion of those UK acquired infections which lead to carriage. In addition, to antenatal screening, universal infant vaccination (at 2, 3 and 4 months) can, in the short term, only prevent the small number of infections acquired in childhood. Economic analysis using current surveillance data is required to assess the possible cost-benefit of universal vaccination. Regardless of this, there is an urgent need to improve selective vaccination and to ensure that a high proportion of antenatal carriers is identified.

Human pigmentation genetics: the difference is only skin deep

There is no doubt that visual impressions of body form and color are important in the interactions within and between human communities. Remarkably, it is the levels of just one chemically inert and stable visual pigment known as melanin that is responsible for producing all shades of humankind. Major human genes involved in its formation have been identified largely using a comparative genomics approach and through the molecular analysis of the pigmentary process that occurs within the melanocyte. Three classes of genes have been examined for their contribution to normal human color variation through the production of hypopigmented phenotypes or by genetic association with skin type and hair color. The MSH cell surface receptor and the melanosomal P-protein are the two most obvious candidate genes influencing variation in pigmentation phenotype, and may do so by regulating the levels and activities of the melanogenic enzymes tyrosinase, TRP-1 and TRP-2.