Groups of school children aged 6–14 years were tested with PPDS and one of the following five antigens simultaneously, namely PPDA, PPDF, PPDG, PPDPL and PPDY. PPDS was prepared from the human tubercle bacillus, and the others were prepared from M. avium, M. fortuitum, the ‘Gause’ organisms, M. marinum and M. kansasii respectively.

It was observed that there was some increase in induration size to PPDA, PPDG, PPDL, PPDS and PPDY with increase in age, while M. fortuitum gave a preponderance of small reactions with no increase of size with age. It was also observed that there was evidence of cross sensitization between PPDS and all the other antigens, particularly in those who had negative or doubtful reactions.

A retrospective survey of transfusion hepatitis associated with a brand of commercial Factor VIII was carried out in 24 Haemophilia Centres from January 1974 until December 1975. Of 371 patients who were transfused with this product, and were followed up, 78 cases of hepatitis affecting 66 patients were found (17·7%). Two types of hepatitis were observed: hepatitis B and non-B hepatitis, the latter with an incubation period of between 8 and 60 days. Twelve patients contracted two types of hepatitis, non-B followed by hepatitis B. Only one patient died after contracting hepatitis B. Four of the suspect batches of concentrate were found to be positive for HBsAg by radioimmunoassay.

There was evidence that the presence of hepatitis B surface antibody in a patient's serum prior to exposure was associated with immunity to hepatitis B. Evidence was presented suggesting that the non-B hepatitis observed was not due to hepatitis A. The factors affecting the incidence of transfusion hepatitis in haemophiliacs were discussed.

Titres of haemagglutination-inhibiting antibody have been measured repeatedly in young women during a period of 6–8 years after the administration of RA27/3 and Cendehill attenuated rubella vaccines. Mean antibody titres were initially 217 after RA27/3 and 159 after Cendehill, but the difference diminished after the first year. Antibody titres were subsequently well maintained in both groups and did not reveal any need for regular revaccination. Mean titres in the Cendehill group were partly maintained by symptomless reinfection which was commoner after Cendehill than after RA27/3. Significant falls in titre were equally common after both vaccines, but low titres of 30 or less were more frequent in subjects who had received Cendehill.

Mean neutralizing antibody titres were initially 15·4 after RA27/3 vaccine and 9 after Cendehill. Titres remained higher after RA27/3 for 3 years, but the difference then diminished and became insignificant during the fifth year.

Revaccination of women with low antibody titres produced significant increases in 69% of subjects when standard RA27/3 vaccine was used; a special preparation of RA27/3 of higher potency produced a similar number of rises (70%) but elicited higher titres and might occasionally be useful for revaccinating women who are likely to come into contact with rubella. Challenge with RA27/3 vaccine produced weaker responses in women who had experienced natural infection than in those whose antibody was vaccine-induced.

Rises in antibody titre after revaccination consisted mainly of IgG, but traces of IgM antibody were detected in one vaccinee who had recently experienced natural reinfection and in 1 woman with naturally acquired antibody who had been challenged with high titre RA27/3 vaccine.

Corynebacterium kutscheri and its alleged avirulent variant were re-examined in C57Bl/6 and Swiss Lynch mice. It was confirmed that while C57B1/6 mice were resistant and Swiss Lynch susceptible to C. kutscheri, the alleged atypical variant was avirulent in both mouse strains. However, following inimunosuppression of C57B1/6 mice with hydrocortisone acetate, it was not possible to reactivate latent C. kutscheri or the alleged atypical variant; this was contrary to previous reports. Moreover, sequential hysterectomy derivation over four generations of C57B1/6 mice did not eliminate their resistance to C. kutscheri compared with conventionally born animals. Vaccination with live attenuated C. kutscheri protected susceptible mice against virulent challenge; vaccination with the alleged atypical variant afforded no such protection. The suggested role of the alleged avirulent variant in resistance to C. kutscheri is challenged and an alternative explanation of such resistance is proposed.

Morphological, biochemical and serological observations suggested that no close relationship existed between C. kutscheri and its alleged avirulent variant isolated from mice at the Rockefeller University. However, both capillary and double diffusion precipitin reactions showed the alleged variant to be a streptococcus of group N, indistinguishable from that previously isolated from Rockefeller University mice.

A total of 1887 bovine sera positive to the Rose Bengal plate test were subjected to other serological tests for bovine brucellosis: the complement fixation test using warm fixation (CFTW), the serum agglutination test (SAT) and the radioimmunoassay (RIA).

The SAT was generally much less sensitive than the CFTW. Many sera, however, gave positive reactions in the SAT but no reaction in the CFTW or the RIA. These SAT reactions were attributed to IgM antibody.

Comparison between the results of the CFTW and the RIA led to the conclusion that 200 ng could be used as a minimum diagnostic reaction in the RIA.

Results obtained from 1887 sera using three serological tests for bovine brucellosis were compared with a serological classification of sera described as the ‘probable infection status’. Sera showing apparent false positive and apparent false negative reactions were identified, and were subjected to supplementary testing as appropriate.

The serum agglutination test (SAT) gave 35% apparent false negative reactions and 5% apparent false positives. The complement fixation test (CFT) gave 12% apparent false negative reactions using warm fixation (CFTW) and at least 5% using cold fixation (CFTC). The routine diagnostic system used in Victoria, in which the CFTW is supplemented by the CFTC and the SAT, gave 9% apparent false negative reactions and 2% apparent false positive reactions. The radioimmunoassay gave 1% or 6% apparent false negative reactions, depending the minimum diagnostic value used.

Atypical reactions in the CFT sometimes caused difficulties in diagnosis.

A modification of Sharpe's microdroplet counting technique is presented which permits viable counting of Bacteroides fragilis. Lysed horse blood was added to 0·1 ml soy digest agar droplets and 2% was found to be the optimal concentration which combined adequate intradroplet colony size with acceptable visibility on the counting screen of the Colworth Droplette machine.

The indirect ELISA technique has been developed successfully to measure antibodies to foot-and-mouth disease virus (FMDV) in cattle sera. Preliminary studies using a standard serum assay show that reproducible results are obtained. The method should prove useful for the examination of antibody titres in sera from large numbers of cattle or other animals.

The properties of pyriminyl (N-3-pyridylmethyl-N′-p-nitrophenyl urea) as a rodenticide against the lesser bandicoot rat (Bandicota bengalensis) in Rangoon, Burma, were investigated in the laboratory. The acute LD 50 and LD 95 dose of orally administered pyriminyl for B. bengalensis were found to be 6·7 mg/kg and 23·0, mg/kg of body weight respectively. When caged bandicoots were given a choice between plain and poisoned baits, the optimum rodenticidal concentration in the bait was found to be 0·25–0·5%. Symptoms of pyriminyl poisoning appear from 1 to 4 h after feeding starts, giving individual animals time to consume from 2 to over 30 LD 50 doses of 0·5% pyriminyl before feeding stops. Deaths occurred from 4 to 96 h after either oral dosing or free-choice feeding. There appeared to be no significant aversion to the poison at 0·25% or 0·5% concentration in foods. The potential hazards and use of pyriminyl as a field bait against populations of B. bengalensis are discussed.

Raw sewage sludge, containing up to 105 naturally occurring salmonellas/l, was included in the diet of one group of cattle at the rate of 1 l/animal/day and in a second group at the rate of 1 l/animal/week. Sterilized sludge, to which had been added 105S. dublin/litre, was included in the diet of a third group of animals at the rate of 1 l/animal/day.

Salmonellas were isolated from all samples of raw sewage sludge but were not isolated from the faeces or carcasses of animals fed on the sludge. Salmonellas were isolated from the faeces of one animal and the carcasses of two animals fed on sterilized sludge to which S. dublin had been added.

Serum samples collected from swine and cattle in Great Britain at various times between July 1971 and July 1977 were examined by haemagglutination-inhibition or single radial haemolysis methods for evidence of infection with influenza A (H3N2) viruses. A small proportion of swine sera collected in each year reacted in the tests but there was no evidence of infection in cattle. The significance of the findings is discussed, with particular reference to the seasonal fluctuations in the prevalence of antibody in swine observed during the period of the study, and their possible relevance to influenzal events in the human population. None of the sera tested had antibody to swine influenza strains (HSw1N1).

An episode of nosocomial infection with Klebsiella aerogenes in a surgical ward, in which six patients were infected, is described. The cause of the outbreak was identified as being contaminated washing-bowls. It is recommended that each patient should have his own bowl, which should be disinfected after use, dried and stored upside-down.

Spilopsyllus cuniculi larvae were found actively feeding on dead rabbit kittens left in nest boxes for up to 12 days.

Mud samples from aquatic environments in many parts of Great Britain and Ireland were collected, mainly in 1975 and 1976, and examined for Clostridium botulinum. The samples were taken from lakes, ponds, reservoirs, marshes, mud-fiats, streams, rivers and canals, and the sampling areas included a number of bird refuges and reserves. Of 554 samples 194 (35·0%) were positive and 167 (30·1 %), 19 (3·4%), 6 (1·1%) and 15 (2·7%) contained types B, C, D and E respectively; 13 (2·3%) contained more than one type. Each type demonstrated was found in both fresh-and salt-water environments. Type B was widespread; types C, D and E were demonstrated in widely separated areas in England and Wales, and type C was found in both the north and south of Scotland. The results were compared with those reported earlier in respect of surveys in the London area, the Norfolk Broads and the Camargue (France).

Antisera against live cultures of 20 strains of Bacteroides fragilis produced in rabbits agglutinated homologous whole-cell as well as O-antigen suspensions with several cross-reactions. Pure specific antisera were produced by absorbing cross-reacting antigens. O-antisera reacted against O-antigens but failed to do so against most whole-cell suspensions, suggesting the presence of surface structures which might have blocked the reactions. The titres of the whole-cell antisera were not significantly higher than those of O-antisera, but the reactions were more definite and easier to read.

This system may prove useful in serological studies of B. fragilis.

Foot-and-mouth disease virus isolates of types O, A and SAT 2, from diseased animals in herds routinely vaccinated twice a year were compared antigenically with the vaccine strains in the complement-fixation, neutralization and radial immunodiffusion tests. It was found that strains which had readily infected vaccinated cattle had R values against the vaccine strain in the complement- fixation and radial immunodiffusion tests of 30 or less, while strains causing primary outbreaks with little spread had R values of 30–40. Threefold differences in humoral neutralizing antibody concentration between the field variant and the vaccine strain in sera from vaccinated animals were likely to be significant in terms of protection.