SUMMARYStudies of the resistance patterns to infection with a murine cytomegalovirus in inbred strains of mice revealed the existence of resistant and susceptible strains. Resistance was found to be associated with possession of the H-2 k allele at the major histocompatibility locus of the mouse. The F 1 hybrid between a resistant strain (C3H/HeJ) and a susceptible strain (BALB/c) was found to have a resistance intermediate between that of both parents, indicating that the gene(s) controlling resistance is partly dominant. Susceptible BALB/c mice could be made resistant to lethal infection by pre-treatment with thioglycollate broth but not by pre-treatment with endotoxin or BCG. Resistant C3H]HeJ mice could be made susceptible to lethal infection by pre-treatment with cyclophosphamide.

ObjectiveTo review the various clinical manifestations of Murray Valley encephalitis (MVE) or Kunjin virus encephalitis in patients in Western Australia. DesignReview of clinical records, 1978 to 1991. PatientsOf 26 reported cases of Australian encephalitis, four were excluded from study because the patient's symptoms were not definitely associated with MVE virus or Kunjin virus infection. Two further cases of MVE were not reviewed as case records were not available. Of the remaining 20 patients, 18 had MVE and two had Kunjin virus encephalitis. ResultsSixteen cases were in the Kimberley, a tropical region where the viruses are endemic. Four were in the subtropical Pilbara and Gascoyne regions. Thirteen of the 20 cases were in Aborigines, of whom 11 were children. The seven non‐Aboriginal patients were adults. Seventeen of 20 cases were in males. The range of neurological disease and outcome was similar to that in previously reported cases, with convulsions, brainstem disease or respiratory failure in severe and fatal cases, and involvement of the spinal cord, cranial nerve or cerebellum in the moderate cases. One mild case without neurological involvement was caused by Kunjin virus. ConclusionsThe poor outcome in young Aboriginal children indicated that disease resulting from exposure early in life was more likely to be severe. The disease in adults, irrespective of racial background, was similar to that in cases reported previously from south‐eastern Australia, but generally milder.

Summary As part of the World Health Organization's international programme on the ecology of influenza, cloacal swabs were collected from 3, 736 birds belonging to 67 species over a 3‐year period in Western Australia for the isolation of ortho‐ and paramyxoviruses. A total of 24 influenza A viruses were isolated from various species of ducks, shearwaters, noddies, terns and a coot, and were sub‐typed as H1N9, H3N8, H4N4, H4N6, H6N2, H6N4, H?N2, H?N6 and H?N9. The H? haemugglutinins did not react in tests with reference antisera. Whether they represent a novel haemagglutinin subtype or atypical members of an established subtype remains to be determined, although preliminary results indicate that they may be atypical members of the H7 subtype. The H1N9 isolate is the first reported isolate of this particular antigenic combination. A total of 17 Newcastle disease viruses was isolated from ducks, noddies, terns and a black‐fronted plover: preliminary results suggest that they are avirulent for domestic chickens. This study indicates that ortho‐ and paramyxoviruses are present in a variety of wild birds in Australia.

The effect of a sublethal dose (0-5 LD50) of influenza A/WSN (H0N1) administered intranasally in the 1st and 3rd weeks of pregnancy was studied in C3H inbred mice. Maternal and neonatal mortality rates were significantly increased by infections in the 3rd week of pregnancy, but not in the 1st week. Infections during the last part of the 1st week significantly depressed the growth rate of neonates. No evidence of viraemia, transplacental transmission or congenital malformations were observed from infections during either week. The results are discussed in terms of a possible model for human influenza infections during pregnancy to determine the potential risks to the mother, fetus and neonate.