Recognising and responding to outbreaks of hepatitis A associated with child day-care centres.

OBJECTIVES: To assess the appropriateness of a protocol for recognising and responding to outbreaks of hepatitis A in child day-care centres and to determine if measles-mumps-rubella (MMR) vaccine was given too soon following the administration of normal human immunoglobulin (NIGH) to young children to control the outbreaks. DESIGN: Prospective surveillance to recognise cases of hepatitis A associated with, and outbreaks of hepatitis A in, day-care centres. MAIN OUTCOME MEASURES: The percentage of initial ('sentinel') cases of hepatitis A associated with day-care centres that were subsequently recognised as also being 'index' cases of outbreaks of hepatitis A in the centres, and the number of children 9-13 months of age when given NIGH who were subsequently given MMR less than three months later. RESULTS: Only 18 (16%) of the 114 sentinel day-care associated cases of hepatitis A were also index cases of outbreaks of hepatitis A in their respective centres. A total of 105 cases of hepatitis A were associated with the 18 outbreak centres; NIGH was administered to 928 (78%) of the attendee children, and to 105 (82%) of the susceptible staff, at the 18 centres. Three of the five children 9-13 months of age when given NIGH were given MMR less that three months later. CONCLUSIONS: Although outbreaks of hepatitis A were common events in day-care centres in north Queensland during the two-year study period, a single case of hepatitis A associated with a centre was a poor predictor of an outbreak within that centre. Precautions must be taken to ensure that live vaccines are not administered to young children too soon after NIGH.

A rapid bioassay screen for quantifying nucleopolyhedroviruses (Baculoviridae) in the environment.

A quantitative bioassay method for the detection of Helicoverpa armigera (Lepidoptera: Noctuidae) singly encapsulated nucleopolyhedroviruses (HaSNPVs) in soil is described. Calibration curves used for estimating soil virus titres in environmental samples were generated by incorporating a sterilised soil into a semi-synthetic insect diet then inoculating known concentrations of an HaSNPV into the soil-diet mixture. Calibration curves were constructed for soil diets containing varying proportions of soil: 0, 1, 5, 10 and 25% soil (w/v). Their accuracy was assessed in a series of blind tests in which the actual soil virus concentration fell within the estimated mean 95% confidence region for each of three samples. The five soil-diet incorporation rates were compared in terms of larval survivorship and growth rate. There was no significant difference in larval survivorship after 10 days (i.e. for the duration of the bioassay period). The stage structure of bioassay larvae at 10 days and pupal weight at 20 days was significantly different for individuals reared on 25% soil-diet in terms of both a slower growth rate and a lower mean pupal weight compared to individuals reared on 10, 5 and 1% soil diets. This did not, however, appear to lead to greater variability in bioassay response at the high soil rate at 10 days. The level of sensitivity of virus detection achieved using this method was extremely good with the LC10 value for mid-first instar H. armigera larvae reared on the 25% soil-diet estimated at 26 polyhedral inclusion bodies (PIBs) per gram of soil. The suitability of using this approach for quantifying Helicoverpa NPVs in Australian soils was assessed by comparing percent bioassay infection across a range of five isolates known to be present in Australia. The effect of soil pH and soil management (cultivated versus non-cultivated) on percent bioassay infection was also examined. In both cases, no significant differences were observed. Finally, percent idopathic mortality, percent NPV infection and estimates of Helicoverpa SNPV concentration in a selection of samples from the Australian environment are presented.

Prenatal diagnosis and prevention of inherited abnormalities of collagen.

There is now strong evidence for the implication of collagen alpha 1(I), alpha 2(I) and alpha 1(III) mutations in many forms of osteogenesis imperfecta and inherited arterial aneurysms (Ehlers Danlos syndrome type IV). A sizeable proportion of these disorders have detectable abnormalities by conventional protein chemistry, immunofluorescence, or more sophisticated DNA analysis. Everyone of them with specific defects or with linkage to appropriate gene markers is therefore amenable to prevention using conventional prenatal diagnosis by chorionic villus biopsy (with fibroblast culture), fetoscopic biopsy (with fibroblast culture), ultrasound diagnosis of the severely deformed fetus, or gene linkage studies by chorionic villus biopsy or amniocentesis. Already many collagen alpha 1(I), alpha 2(I) and alpha 1(III) mutations have been characterized including point mutations, small and large deletions and regulatory mutations. Many others are likely to be rapidly studied by exploiting recent advances in DNA technology, and other strong candidate genes include collagen II (some chondrodystrophies), collagen VI (certain arterial and cardiovascular diseases) and collagen VII (dystrophic epidermolysis bullosa). Other important common diseases are likely to include osteoporosis, osteoarthritis and cerebral aneurysms. A detailed review is provided of collagen interstitial genes and proteins, together with a description of the various forms of osteogenesis imperfecta and Ehlers Danlos syndrome in which either collagen alpha 1(I), alpha 2(I) or alpha 1(III) mutations have been identified. Appropriate restriction length polymorphisms (RFLPs) useful in identifying carriers of these mutant genes are also described.

Struma ovarii: a case report.

A patient with struma ovarii and hyperthyroidism is described. She was treated for Graves' hyperthyroidism at age 22 and received thyroxine for post-operative hypothyroidism. Twenty years later she became thyrotoxic and was treated with antithyroid drugs and radioiodine. Diagnosis of struma ovarii was made by radioiodine profile scanning and an ovarian tumour was removed. This had the pathological features of struma ovarii and autoradiographic evidence of pre-operatively administered 125I was seen in the lesion. The patient had positive results for long acting thyroid stimulator (LATS) and LATS-protector (LATS-P) pre- and post-operatively. Bioassays for thyroid stimulators were positive post-operatively but radioreceptor assays for TsAb were consistently negative. It is suggested that profile scanning is an appropriate investigation for diagnosis. It is not clear whether the lesion was autonomous or being stimulated by circulating thyroid stimulators.

Mastalgia and total body water.

Total body water (TBW) was measured early and late in a menstrual cycle in 56 women, 39 of whom had breast pain. The remainder were asymphtomatic controls. Most women did not conform to the traditional view that there is a premenstrual increase in TBW. In some TBW decreased, while in others there was no change from the early cycle measurement. No TBW pattern correlated with any syndromes of breast pain or with any psychoneurotic profile.