Evaluation of a commercial ELISA for detecting Norwalk-like virus antigen in faeces.

A commercially available enzyme immunoassay, the IDEIA Norwalk-like virus (NLV) enzyme linked immunosorbent assay (ELISA; Dako Cytomation, Ely, UK) for detecting NLV antigen in faecal samples and determining the NLV genogroup was evaluated. The performance of the ELISA was compared with that of electron microscopy and the reverse transcription polymerase chain reaction by testing a panel of faecal samples collected from patients involved in outbreaks of gastroenteritis. When compared with reverse transcription-polymerase chain reaction (RT-PCR), the ELISA had a sensitivity and specificity of 55.5 and 98.3%, respectively. This compares with a sensitivity and specificity for EM of 23.9 and 99.2%, respectively. The sensitivity and specificity of the ELISA for determining the aetiology of a Norwalk virus-like outbreak, based on two or more positive samples within an outbreak, were 52.2 and 100% when two samples were collected from an outbreak and 71.4 and 100% when six or more samples were collected. The ELISA correctly identified the NLV genogroups of viruses previously characterised by partial DNA sequencing. The ELISA is a suitable alternative to the preliminary screening by EM for investigating outbreaks of gastroenteritis. Outbreaks, negative by ELISA should be examined by RT-PCR in order to detect strains non-reactive in the assay and virus strains from representative ELISA positive outbreaks should be characterised fully to allow the genetic diversity of NLVs co-circulating in the population to be described.

Evolving costs of long-term left ventricular assist device implantation.

BACKGROUND: To examine the long-term costs of implanting a left ventricular assist device, we reviewed the initial hospitalization and outpatient costs for 12 patients who received a vented electric left ventricular assist device, and projected the first-year costs. METHODS: We used the ratio-of-cost-to-charges method to measure hospital costs and payments for physician time. We examined time trends in the resource use of 50 pneumatic left ventricular assist device recipients, using actuarial techniques and regression modeling. RESULTS: The average actual cost of left ventricular assist device support is $221,313 over an average of 9.5 months. If there had been no Food and Drug Administration regulatory policy precluding hospital discharge before 30 days, this value would have been $201,148. Based on this latter figure, the average predicted first-year cost is $219,139. The length of the intensive care unit stay, one of the most costly components of care, decreased significantly over time. CONCLUSIONS: The high costs of left ventricular assist device implantation are similar to those reported for cardiac transplantation. Given their success in supporting survival, we anticipate that these devices will be similarly cost-effective. However, further research is imperative to determine the cost-effectiveness of these devices beyond the introductory phase, when costs, benefits, and Food and Drug Administration requirements have stabilized.

Salivary diagnosis of measles: a study of notified cases in the United Kingdom, 1991-3.

OBJECTIVES: To validate a method for salivary diagnosis of measles and to assess the diagnostic accuracy of notified cases of measles. DESIGN: Blood and saliva samples were collected within 90 days of onset of symptoms from patients clinically diagnosed as having measles and tested for specific IgM by antibody capture radioimmunoassay. SETTING: 17 districts in England and one in southern Ireland during August 1991 to February 1993. SUBJECTS: 236 children and adults with measles notified by a general practitioner. RESULTS: Specific IgM was detected in serum in only 85 (36%) of the 236 cases. In cases associated with outbreaks and tested within six weeks of onset, 53/57 (93%) of samples were IgM positive, thereby confirming the sensitivity of serum IgM detection as a marker of recent infection. The serological confirmation rate was lower in cases with a documented history of vaccination (13/87; 15%) than in those without (70/149; 47%) and varied with age, being lowest in patients under a year, of whom only 4/36 (11%) were confirmed. Measles specific IgM was detected in 71/77 (92%) of adequate saliva samples collected from patients with serum positive for IgM. In cases where measles was not confirmed, 6/101 had rubella specific IgM and 5/132 had human parvovirus B19 specific IgM detected in serum. CONCLUSIONS: The existing national surveillance system for measles, which relies on clinically diagnosed cases, lacks the precision required for effective disease control. Saliva is a valid alternative to serum for IgM detection, and salivary diagnosis could play a major role in achieving measles elimination. Rubella and parvovirus B19 seem to be responsible for a minority of incorrectly diagnosed cases of measles in the United Kingdom and other infectious causes of measles-like illness need to be sought.

Congenital rubella in south India: diagnosis using saliva from infants with cataract.

PIP: Congenital rubella is a preventable disease which has largely been controlled through immunization in the developed world. Serological surveys in India, however, indicate that up to 45% of women of childbearing age are susceptible to rubella and potentially at risk of infection during pregnancy. The authors tested saliva and blood serum samples from 95 consecutive infants of mean age 6.2 months with congenital cataract presenting to the pediatric department of the Aravind Eye Hospital in 1993-94 to determine whether the detection of rubella specific IgM from saliva is as reliable as from serum for diagnosing rubella infection and whether rubella is an important cause of congenital cataract in south India. 36 children of mean age 7.3 months attending the same clinic over the same period with a diagnosis of watering eyes served as controls. Serum samples were taken from 61 children with cataract, while saliva samples rich in crevicular fluid were collected from all 131 children using the Orasure device. These samples were then tested for the presence of rubella specific IgM by antibody capture. Rubella specific IgM was detected in saliva and serum in 17 paired samples and was absent in 44 paired samples. Saliva testing gave no false positive and no false negative results compared with serum. 25 of the 95 cases had congenital rubella infection confirmed by detection of rubella specific IgM in saliva. However, congenital rubella was suspected clinically in only 19 of the 25 cases. No control had raised rubella specific IgM.^ieng

Molecular diversity of noroviruses associated with outbreaks on cruise ships: comparison with strains circulating within the UK.

The molecular diversity of norovirus (NV) strains associated with 26 outbreaks of NV gastroenteritis has been determined. The outbreaks occurred on 14 cruise ships from seven cruise lines, during the period from 1998 to 2002. The ships cruised in seas worldwide, including the Mediterranean, the Baltic and the Caribbean. Genogroup I NVs were more common in the cruise ship setting than in hospitals, with 38% of the cruise ship outbreaks associated with genotype I NVs, as compared to < 10% in hospital and other semi-closed institutions in the UK. Outbreaks on cruise ships were more common in the period April to September, than in the winter. Two mixed genogroup I and II outbreaks were detected, which suggested contaminated food or water as the source of the infection.

Two levels of alliance formation among male bottlenose dolphins (Tursiops sp.).

In Shark Bay, Western Australia, male bottlenose dolphins (Tursiops sp.) cooperate in pairs and triplets to sequester and control the movements of females. We refer to this behavior as "herding" and to the male pairs and triplets as alliances. During a 25-month study (1987-1989) on the social relationships of males, we documented herding in 10 alliances. Males preferentially herded nonpregnant females likely to be in estrus. Alliance members associated with one another consistently when not herding females. Each alliance associated preferentially with one or two other alliances. Occasionally, two alliances combined and took females from another alliance or defended females against such efforts. This study documents multiple-level male alliances within a social group outside of humans.