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Genome analysis was performed on 125 adenovirus isolates from conjunctival swabs of patients with conjunctivitis obtained in Glasgow between 1981 and 1984. A summer outbreak in 1981 was mainly due to species 3 adenoviruses, of which genotype 3GB and five different genotypic variants cocirculated. Three species 3 variants were also observed in 1982. The genome changes of variants were located on physical maps of the Ad3 reference strain and found to be clustered near the ends of the adenovirus DNA (including the fiber area), whereas the hexon coding region was unaltered. In contrast to the genome heterogeneity observed among the species 3 adenoviruses collected in Glasgow in 1981 it was found that all 69 Ad3 isolates obtained from an outbreak of pharyngoconjunctival fever in a boarding school near London during the summer of 1981 possessed the 3GB genotype.

An outbreak of pharyngoconjunctival fever caused by adenovirus type 3 was studied in a boarding school for 800 boys aged 11-18 years. A total of 96 clinical cases were confirmed by laboratory tests. Clinical infection rates were higher in the younger boys but total infection rate did not vary with age. Previous infection provided 88% protection against reinfection. The techniques of virus isolation, complement fixation and neutralization were compared in the diagnosis of cases. Virus isolation diagnosed 86% of confirmed cases. Where acute sera (collected at onset) and convalescent sera (collected within one month) were available complement fixation and neutralization tests each diagnosed 96% of cases.

SUMMARY Sera from 1258 individuals have been tested by four laboratories for rubella antibody by both the haemagglutination-inhibition and single radial haemolysis techniques. There was good agreement between the results obtained by the two methods. Although sheep red blood cells were used in the single radial haemolysis plates, no problems were encountered with sera from patients with infectious mononucleosis.The single radial haemolysis technique was found to be simple, convenient, and reliable, and suited to the rapid screening of large numbers of sera to assess susceptibility to rubella in the context of a vaccination campaign. However, since the technique does not detect anti-rubella IgM, it should not be used as the only test to investigate suspected recent infection.The haemagglutination-inhibition (HAI) test is at present the one most widely used for detecting antibodies to rubella virus. However, this test is laborious and time-consuming to perform: sera must be pretreated to remove non-specific inhibitors; they may require absorption to remove red cell agglutinins; and they must be individually diluted. In addition, the test involves a large number of variables which can give rise to poor reproducibility (Gust et al., 1973).The single radial haemolysis (SRH) technique was first developed to detect and measure influenza antibody (Russell et al., 1975;Schild et al., 1975) and, because of its simplicity, accuracy, and reproducibility, has now been used for detecting antibodies against rubella virus.We here report an evaluation of the SRH technique as a replacement for the HAI test in the routine screening of large numbers of sera for rubella antibody. Sera were examined undiluted. A 10-,ul volume of test serum was added to each well and allowed to diffuse through the gel overnight at 40C. The gels were then flooded with a 1:10 dilution of guinea-pig complement (Wellcome Reagents Ltd) and incubated in a humidified atmosphere at 370C for three hours.Plates were examined immediately or fixed in 10% formol saline. The diameters of the zones of haemolysis were then measured, and the corresponding annulus areas were calculated (total area minus area of well).Since some human sera contain sufficient antisheep red blood cell antibody to produce a very small zone of lysis, sera were defined as SRHpositive only if the area of lysis exceeded 5 mm2, that is, the lysis extended more than 0-5 mm from the edge of the well.

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