The sensitivity of the haemagglutination, complement-fixation and indirect fluorescent antibody tests in the diagnosis of primary and recurrent hydatid disease is presented. In the first, diagnostic titres were obtained in 90%, 80% and 96% of 50 patients with hepatic and 64%, 60% and 68% of 25 patients with pulmonary cysts, respectively. In the postoperative study of 62 patients, elevated titres of HA, CF and IFA antibodies in 30 led to the presumptive diagnosis of recurrent disease, confirmed later by radiological and surgical follow-ups. In the 32 others the proportion of positive reactors was 29%, 6% and 28% in HA, CF and IFA tests. These patients had no detectable cysts. This indicates that in post-operative patients a negative CF test may be of a better prognostic value in indicating absence of cysts than the HA and IFA tests.

The ability of a new, surface-antigen-adsorbed influenza virus vaccine to induce serum antibody in hamsters, and to protect these hamsters against subsequent homologous virus challenge, is reported. In addition, similar studies in hamsters have also been carried out using the surface antigen material prior to adsorption to the aluminium hydroxide carrier. The new, adsorbed vaccine is at least as effective as inactivated saline influenza virus vaccine in inducing serum antibody and protection in hamsters; the unadsorbed surface antigen material, however, did not confer protection to hamsters challenged subsequently with homologous virus.

A group of 23 volunteers were each inoculated with 600 CCA of a new form of influenza virus A/England/42/72 vaccine; this vaccine consisted of purified haemagglutinin and neuraminidase antigens adsorbed to alhydrogel. No significant reactions to the vaccine were reported. Twenty-two volunteers produced increased titres of serum HI antibody, and all showed increased titres of NI antibody after immunization. Thus, for volunteers with no pre-immunization serum HI antibody, the geometric mean titre of serum antibody increased from 1/5 to 1/196 after immunization. Ten volunteers developed local neutralizing antibody after immunization; this antibody response was detected most frequently in volunteers who showed the greater serum antibody response to immunization, and in nasal washings with the higher concentrations of protein and IgA. Ten weeks after immunization, the vaccinees and a group of matched controls were inoculated intranasally with attenuated A/England/42/72 virus. Evidence of infection with the challenge virus was found in 14 of the control subjects and in one of the vaccinees. The results indicate that the surface-antigen-adsorbed vaccine induced high titres of serum antibody, and gave significant protection against challenge infection.

Substantial transfer of R factors occurred in vivo, under certain conditions, in the rumen of adult sheep in the absence of any antibiotic treatment. A starvation period of 24–48 hr. was required to produce the conditions necessary, when even quite low inocula (ca. 103 cells) of donor and recipient E. coli could grow within the rumen and reach a population density sufficient for transfer to take place. The results indicate that under the same conditions R factors may be transferred between organisms in the lower intestinal tract also. Without the starvation period, the inoculation of even massive numbers (1010 cells) of the same organisms resulted in almost no detectable transfer.

Some of the experimental animals on which a starvation period was imposed became carriers of either the inoculated recipient E. coli, or of R factor bearing coliforms, and these formed 1–10% of the total coliform population of the faeces for at least 6 weeks.

Mud samples collected during 1974 from a large proportion of the lakes and waterways of London were examined for Clostridium botulinum. Of 69 such sites, 50 (72·5%) contained at least one type of the organism. Of the 50 positive sites, 31, 12, 1 and 10 contained, respectively, types B, C, D and E. Most of the demonstrations of type B required trypsinization of culture filtrates. An examination of 7 lakes in Edinburgh, made for the purpose of comparison, showed that 4 contained type B and one type C.

An analysis of the results gave quantitative information on the value of (1) resampling apparently negative lakes, (2) the use of both heated and unheated culture inocula, and (3) trypsinization of culture filtrates.

A virus was isolated from pock-like vesicular eruptioiis of camels in Northern Kenya. This virus was shown to be a pox virus with many characteristics of members of the Orthopox group. It appears to be identical with camelpox strains from Iran and has similar properties to certain East African variola strains.

Variants of type A FMD virus from the Eastern Mediterranean region over the years 1964–72 have been shown to belong to a group distinct from the Western European strains as represented by A5 Westerwald. This group appears to derive from the A22 strain first recognized in 1964 and indicates the possibility of new strains supplanting old in the field.

The vibriocidal activity of Inaba and Ogawa antisera, from which cross-reacting agglutinin had been absorbed, was specific for Vibrio cholerae strains of the homologous serotype. No vibriocidal action against strains of the heterologous type was detected.

The sera appeared to be equally effective in killing organisms of different biotypes (classical, intermediate, and EITor), provided that these were of the homologous serotype (Inaba or Ogawa). However, they had been raised against strains of the classical biotype only; and sera resulting from immunization with other biotypes had not been prepared.

The implications of these findings in immunity to cholera are discussed.

A total of 21 rubella seronegative children vaccinated subcutaneously with Wistar RA 27/3 strain live attenuated rubella vaccine in a family study of vaccine virus transmissibility were reviewed after 6 years. Haemagglutinating inhibiting (HAI) antibody titres of sera collected 46 days, 2 years and 6 years after vaccination were compared. Antibody titres in the vaccinated subjects were not significantly influenced by time, infection in susceptible siblings or revaccination.

A study of the incidence of diphtheria in the State of Victoria, Australia, was carried out. Numerical analysis of the characteristics of 264 strains of Corynebacterium diphtheriae isolated between 1962 and 1971 placed them into 18 varieties plus six strains which were unique in their combination of reactions to the characteristics examined. During the 10-year period, some varieties appeared inter mittently and were recognized by certain defining characteristics but exhibited a gradual change in their antigenic structure. In contrast, when the outbreaks were examined over shorter periods of time, a number of varieties and single strains were found which differed greatly from each other yet possessed the same major serotype antigen. These findings are discussed in terms of a 'one-parent' concept in which the varieties and single strains represent phases of a common ancestor.

By inspection and analysis of the characteristics of the strains, certain associations were apparent. For instance, a correlation was found between the antigenic structure of the organism and the colonial appearance on tellurite blood agar. Similarly, correlation was observed between bacteriophage type, diphthericin type and biochemical activity in that a strain which was highly active in one of the properties was also very active in the other two.

Comparative clinical trials of live attenuated and detergent-split subunit influenza virus vaccines were undertaken with 1048 volunteers in Western Australia. Volunteers were divided into three main groups, each of which received either live virus vaccine or a saline control administered intranasally, or subunit vaccine injected subcutaneously. No differences were recorded between the three groups in their post-vaccination symptoms. Serum samples were collected at various times up to 50 weeks after vaccination, and antibody titres were measured by haemagglutination-inhibition (HI) tests and, for 231 volunteers, by virus neutralization tests. The two vaccines were almost equivalent in inducing seroconversion in vaccinees with pre-trial HI titres of 96 or less, but the subunit vaccine stimulated a higher geometric mean HI antibody titre. The longevity of the HI antibody response was greater for the live virus vaccine. The height of the response and the longevity of neutralizing antibody were the same for both vaccines. Both vaccines provided a high degree of protection against epidemic A/England/42/72 influenza, and some protection against A/Port Chalmers/1/73 influenza.

Studies in a newly built hospital furnished with complete air conditioning where most of the patients are nursed in 6-bed rooms showed that the transfer of air from one patient room to another was very small, especially when there was substantial flow of air in a consistent direction between the patient rooms and the corridor, and that the direct transfer of airborne particles was even less. There was, however, no evidence of any reduction in the rates of nasal acquisition of Staphylococcus aureus compared with those to be found in naturally ventilated hospitals.

The numbers of Staph. aureus found in the air of a given room that appeared to have originated from patient carriers in other rooms were many times greater than could be accounted for by direct airborne transfer. Although there was evidence that many carriers were not detected, detailed study showed that this excess transfer to the air of other rooms was genuine. It seems probable on the basis of investigations in this hospital and elsewhere that this excess transfer occurs in-directly, through dispersal from the clothing of the nursing and medical staff into the air of another room of strains with which their outer clothes have become contaminated while dealing with patients.

Reduction in direct airborne transfer of micro-organisms from one room to another, whether by ventilation or other means, can only be of clinical advantage if transfer by other routes is, or can be made, less than that by the direct airborne route.

Using a laboratory downward displacement vertical autoclave with the help of thermocouples recorded on a 12 point multichannel strip recorder, the risk of failing to sterilize laboratory discard buckets has been demonstrated. The use of proper temperature and time controls can prevent this risk.

A load in a bucket with perforated sides is more easily sterilized than in a solid bucket. Wire baskets, where appropriate, facilitate the sterilizing practice. The addition of water to a bucket does not reduce the time of heating up.

It is desirable that sealed bottles of media should not be sterilized in simple downward displacement autoclaves, but if used, strict monitoring of temperatures and times is essential both in the heating up stage and especially in the cooling stage. The temperatures in bottles are slow to rise and very slow to fall. Bottles at high temperature 80–405° C. or over have a high internal pressure which can allow the bottles to explode when subjected to thermal shock if removed too early.

It is suggested that all laboratory autoclaves should have a load temperature simulator or similar device to control the temperature of the load during the cycle automatically. For the sterilization of fluid media, it is suggested that, in addition to a simulator there should be accelerated cooling to reduce damage to the media and, what is more important, to rapidly bring down the temperature and thus the internal pressure in the bottles to a safe level. The opening of the sterilizer door or lid should be automatically controlled by the load temperature simulator.