The serum and whey agglutination test were compared on paired samples from thirty-five cases of bovine abortion associated with Salmonella dublin infection. The whey test proved nearly as useful as the serum test for confirming an active infection though it was only practicable to examine the whey for flagellar antibodies. S. dublin was isolated from nearly half of the milk samples obtained within the first week of abortion but none of those collected after the fourth week. The whey test proved of no value in retrospective identification of abortion cases. The trial using the milk ring test was disappointing.

A total of 3217 strains of coagulase-negative staphylococci and micrococci were tested for susceptibility to a collection of phages isolated from coagulase-negative cocci; it was concluded that a useful typing scheme could be developed. Of the strains of Baird-Parker's biotype 1, 72% were lysed by one or more phages, although rather a large proportion of strains are lysed by many phages to give a complex typing pattern.

Normal persons commonly yield 10 or more distinguishable strains of coagulase-negative cocci in cultures from the nose and the skin.

Modified Moore's swabs, placed in sewers for 5 days, were used to concentrate salmonellas from sewage. Duplicate cultures of swab strips in selenite broth were incubated at 41 and 37°C. respectively. Salmonella organisms were recovered consistently from the swabs when the enrichment broths were incubated at 41°C., However, when equal portions of the same swabs were incubated at 37°C., only 22% of them yielded Salmonella organisms. These results indicate an advantage in incubating the selenite broths at 41°C. rather than 37°C. in attempting to isolate salmonellas from sewage.

One hundred and fifty faecal samples were examined for salmonellas by culture in selenite broths incubated at 41 and 37°C. Twelve (8%) samples were positive at 41°C. compared to only 10 (6·7%) positive samples at 37°C. This difference is not statistically significant to indicate an advantage of the elevated-temperature of incubation over the conventional temperature in attempting to isolate salmonellas from human faeces. Moreover, results of the recovery rates of S. paratyphi B, S. typhi, and S. typhimurium indicate that an incubation temperature of 37°C. is more appropriate for recovering salmonellas from artificially infected faecal samples than an incubation temperature of 41°C. This stresses the inability of laboratory studies to mimic conditions in nature.

A dipthericin typing scheme has been constructed using 441 strains of Corynebacterium diptheriae isolated in eastern Australia from 1962 to 1971. Ten types have been distinguished using seven strains of C. diphtheriae and two strains of C. belfanti as indicators of the diphthericins produced by the newly isolated strains. Strains grouped into types L2, L3 and L3a were found only in Melbourne and types L1 and L4 were predominant in Sydney. Type L5 strains were isolated intermittently throughout the period of study and were found in all eastern states. Numerical analysis of the characteristics of the strains suggests that associations exist between, on the one hand, diphthericin type and, on the other hand, bacteriophage type, serotype and biochemical activity.

Strains of Corynebacterium diphtheriae isolated from a small outbreak in the restricted environment of a Mental Hospital were examined. All belonged to one serotype, but there was marked variation in diphthericin type, in sensitivity to bacteriophages and in the minor antigens possessed. One strain was non-virulent and laboratory-produced variants of this non-virulent strain showed changes in some of the characteristics used in the identification and typing of the organism, such as diphthericin type, sensitivity to bacteriophages and diphthericins, virulence, starch fermentation and, to a lesser extent, in antigenic structure. The epidemiological and experimental findings are consistent with the hypothesis that the strains isolated, both in the hospital and in the laboratory, were derivatives of a single parent and the mechanism of some of the variations could be related to changes in some structural component such as the cell membrane or the cell wall.

The morphological, cultural, biochemical, serological and pathogenic properties of two bacterial strains of the group designated ‘Br. suis biotype 5’ were examined. Both strains were found to be atypical of the genus Brucella in many of these characteristics. No serological relationship to known brucella strains could be detected. On the basis of the evidence obtained the two strains examined were classified as Moraxella duplex and the status of ‘Br. suis biotype 5’ questioned.

Isolations of subgenus III salmonellas (arizonas) made in the regional Public Health Laboratory, Cardiff, between 1959 and 1971 are reviewed. The techniques of isolation are listed for the various materials examined. The necessity of using bismuth sulphite agar as a plating medium is stressed, as some strains might appear on brilliant green MacConkey agar as rapid lactose fermenters and be missed. The serotypes isolated in Cardiff are discussed with reference to isolations by other authors. The culture of a subgenus III salmonella from pig faeces is described. It is thought that this is the first record of such an isolation from a pig in the United Kingdom.

H phase II → phase I conversion of Salmonella thompson was studied at different temperatures. All strains were isolated from one outbreak, and a convenient method of phase conversion was sought. In our hands this was best effected at 20° C.

In a factory population the occurrence of reactions to tetanus toxoid was recorded after 6740 injections. The incidence of general reactions was 0·3 % and of local reactions 2·6%. The local reaction rate to the first injection of the basic immunization course was 0·9%, to the second injection 2·7%, and to the third injection 7·4%. To booster injections the rate was 1·6%. The local reaction rate was appreciably higher in women than in men – 14·4 % and 5·7 % respectively in the case of the third injection – and the incidence among women increased with age.

Tetanus vaccine containing 10 Lf of toxoid caused fewer reactions than one containing 20 Lf, but a reduction in the content of aluminium adjuvant did not affect the reaction rate.

Almost all reactors were found to have a satisfactory serum antitoxin concentration at the time of the reaction or developed a satisfactory immunity within 1–6 months.

Skin tests were made in 32 hypersensitive patients. Neither the diluent, thiomersal preservative, nor the culture medium appeared to be responsible for hypersensitivity. The degree of hypersensitivity elicited by a special highly purified toxoid was only very slightly less than that elicited by the commercially pure toxoid. It is suggested that reactions are largely due to the toxoid antigen itself rather than to impurities or other components of the vaccine.

The findings of a survey on the ecology of an alphavirus over the years 1964–9 are reviewed. Evidence is presented to show that wild birds constitute a vertebrate reservoir of the virus and that mosquitoes, primarily Culiseta tonnoiri and Culex pervigilans, which are both endemic New Zealand species, are responsible for summer transmission.

Serological evidence of infection was obtained in all years and evidence is presented to indicate that the virus is enzootic rather than being reintroduced each spring. The number of birds with antibody increased before mosquitoes became active in the spring and possible explanations of this are discussed.

The mean temperature in the hottest month in the study area is substantially below that in other areas with enzootic mosquito-borne viruses and experimental studies showed that Whataroa virus was able to replicate more rapidly in mosquitoes at low temperatures than any arboviruses previously studied.

The main natural focus of infection appeared to be in a modified habitat and the introduced song thrush (Turdus philomelos) to be the main vertebrate reservoir host.

Results are presented on tests carried out over the past 5 years to measure the antibody titre of various rabbit populations to a soluble antigen of myxoma virus. In an unexpectedly high percentage of immune rabbits the antibody fell below measurable titres, and later rose to measurable titres without the advent of an observable epizootic of myxomatosis. The re-stimulation of the immune response is discussed in terms of re-infection and virus reactivation.

This report has been complied by the Secretary, Dr P. Nicolle, from the material provided by the Directors of National Centres and of some Regional Centres of the ICEPT. It was delivered at the meeting of the ICEPT during the 10th International Congress of Microbiology on 8 August 1970 in Mexico. The English version was prepared and edited by the Chairman, Dr E. S. Anderson.

The incidence of Salmonella in tortoises and frogs captured in Istanbul was studied. From 31 out of 40 tortoises (77·5%) and from 16 out of 311 frogs (5·1%) salmonella strains belonging to 18 and 14 serotypes respectively were isolated.

The European rabbit flea Spilopsyllus cuniculi (Dale) was first released on Macquarie Island in December 1968. The flea has survived and bred on the island and about 30% of the rabbits sampled from the original release area in January 1972 were flea-infested.

Two outbreaks of human infection with Yersinia enterocolitica in Shizuoka, Japan are described. This is the first report of community outbreaks of infection with this organism in Japan, and possibly in the world. All the strains isolated in each outbreak belonged to 0 antigen group 3, biotype 4, of the species. Despite much effort, the source and mode of spread of the infection were not established.

Prototype strains of the influenza A (H3N2) virus can be arranged on a gradient showing the degree of the antigenic drift which the haemagglutinins of the strains have undergone. The demonstration of fine antigenic differences is based on an antiserum absorption test which allows a detailed antigenic analysis of strains. The gradient provides information on variation in strains occurring in different geographical areas and its use may be helpful in differentiating between introduced strains and locally developing variants.

The nature of the antibody response of cattle to the antigen of Yersinia enterocolitica IX cross-reacting with Brucella spp. was examined. Density-gradient ultracentrifugation, ion-exchange chromatography, antibody adsorption and elution and disulphide bond reduction tests showed that both 19 S IgM and 7 S IgG1 and IgG2 antibodies were produced in response to the cross-reacting antigen. The highest titres of cross-reacting antibodies were detected by the agglutination and Coombs antiglobulin tests. Production of complement-fixing and precipitating antibodies cross-reacting with Br. abortus was transient and high titres were not attained.

In contrast, although infection with Br. abortus also evoked cross-reacting antibodies of the IgM and IgG classes, much higher titres were produced in the complement fixation and precipitation tests and these persisted for long periods. At all stages of the serological response to both organisms, the two infections could be differentiated by the quantitative Rose Bengal plate test.

Respiratory disease on Tristan da Cunha has been observed since the islanders returned in 1962. An epidemic of unprecedented severity occurred in the winter of 1971 and involved 273 (96%) of 284 islanders, 92 of whom had two attacks. The epidemic was apparently introduced by the Tristania.

The illness of both first and second attacks ranged from mild to severe but there were some differences. There were two deaths, both in elderly persons with chronic chest disease and heart failure. Serological evidence suggests that this was due to influenza A2 of the Hong Kong serotype H3N2

The cell membrane of Mycoplasma gallisepticum was isolated by lysing the cells with digitonin. Chemical and density-gradient analyses and electron microscopy showed the isolated membranes to be relatively free of cytoplasmic contaminants. The density of the membranes exceeded that of other mycoplasma membranes, indicating a higher protein content. Small vesicular extensions seen in the sectioned membranes were interpreted as empty blebs.

The isolated membranes, but not the cytoplasmic fraction, elicited in chickens the production of growth-inhibiting, agglutinating and haemagglutination-inhibition antibodies to M. gallisepticum in titres resembling those obtained by injection of whole cells. The peak of the serological response varied with the serological test employed. The rapid slide-agglutination test became positive as early as 3 days after the first injection of only 50 μg. of membrane protein. The haemagglutination-inhibition antibody titre reached its peak at about 10 days after the first injection, while that of the growth-inhibiting antibodies was reached only at about 25 days. The addition of adjuvant to the membrane antigen did not improve the production of the growth-inhibiting antibodies in chickens, but it produced some improvement in rabbits. Our results support the thesis that the chief immunogens of M. gallisepticum reside in the cell membrane of this organism.

A case of typhoid fever caused by Salmonella typhi occurred in Geneva. The patient was probably infected in Mexico City. The strain isolated from this patient corresponds with the description of the Mexican S. typhi strain, since it is a degraded Vi-strain resistant to chloramphenicol, streptomycin, sulphonamides and tetracyclines. It carried an fi− transferable R factor with a CSSuT resistance pattern. It can be accepted that this case forms part of the Mexican outbreak of chloramphenicol-resistant typhoid fever which has already been observed in visitors to Mexico from England and the United States.