The sheep and goat pox viruses isolated in Kenya are not host specific as in the Middle East and India. The virus strains from one species are of a similar patho-genicity for the other, and the same virus appears to occur in field outbreaks in mixed flocks. A silent infection with no skin lesions occurs in the field outbreaks.

The virus grows well in lamb testis cell cultures, it does not haemadsorb nor haemagglutinate and is ether sensitive. Most strains could not readily be adapted to grow on the chorioallantoic membrane of embryonated eggs; one isolation only was made in this way. Staining of the virus inclusions showed that they were of DNA; the virus resembled that of lumpy skin disease in many characteristics.

It was possible to cross-protect both species with virus of sheep or goat origin. A vaccine was made from tissue culture virus adsorped onto aluminium hydroxide gel and treated with formalin.

The spread of a 'cream' mutant in a wild population of house mice is reported. The hypothesis that the gene responsible for the colour, extreme chinchilla, ce, has spread because of linkage with a major gene for warfarin-resistance, is tested by a linkage backcross.

The results prove that a major gene does exist, that it is very closely linked with frizzy, fr, in chromosome 7, which in turn is linked with ce, that it is fully dominant in females at 4 months of age, and that its partial dominance in males is under the control of modifiers.

The symbol War is proposed for the gene. Its position in chromosome 7 is analagous with the position of the resistant gene, Rw2, in the rat in the analagous chromosome.

The adaptive significance of this finding is discussed, as also are reports of certain other mutants in wild populations of mice.

A survey of the bacterial flora present at various positions in 130 male and female washrooms and toilets is reported. Several bacteria of faecal origin were found in large numbers: the areas likely to be the most important sources of cross-infection from faecal contamination are indicated. The results are used to assess priorities for disinfection.

This paper gives an abbreviated account of part of a research programme which followed the Aberdeen typhoid outbreak of 1964. Chloramphenicol, the main antibiotic used in treatment, was shown to have a minimum inhibitory concentration (MIC) of between 5 and 2.5 μg./ml. for the S. typhi phage type 34 of the outbreak. The MIC for methacycline was between 2.5 and 2 μg./ml. Whereas the deep and shallow broth techniques used gave similar results with these antibiotics, the MIC for ampicillin, and also cephaloridine, was less in the deep than in the shallow broths.

Serum assays in patients given ampicillin or cephaloridine yielded abnormally high concentrations of both antibiotics when S. typhi phage type 34 was the test organism whereas, with other test organisms, the concentrations were within expectation. These abnormally high values fell within expected values when the sera under investigation had first been heated to 56° C. for 30 min. before assay against the S. typhi of the outbreak.

The findings with ampicillin suggested that dosages given were satisfactory. With cephaloridine the concentrations found in patients' sera seemed to show that twice daily doses of 0.5 g. fell short of adequacy.

A range of new Tubercul ns prepared from extracts of living organisms belonging to 12 mycobacterial species has been used to assess the effect of BCG immunization and contact with environmental mycobacteria on Ugandan adults. A total of 2,456 tests were carried out on 562 people, 86% of whom came from three areas selected for special study. These areas were chosen on the basis of occurrence of leprosy and M. ulcerans infection and on data concerning the distribution of environmental mycobacteria. It was found that the effect of BCG was small compared with that previously observed amongst Kenyan schoolchildren, but that the effect of geographical origin was considerable. There was some correlation between the percentages of reactivity to the reagents and the frequency of mycobacteria in the environment.

An account is given of some human diseases which affect one sex more than the other.

An age–sex relationship has been noted among British patients with acquired toxoplasmic lymphadenopathy. This is compared with the findings of other European workers.

A possible explanation is offered taking all these diseases into consideration together with some of the experimental work done in animals and some of the variations in immunological responses by man.

A seroepidemiological survey of a sample – roughly representative by age and sex – of 2744 persons of the Greater Athens area revealed that hepatitis B virus (HBV) infections are highly endemic in Greece. Hepatitis B surface antigen (HBsAg) was detected in 72 (2·6 %) of them. The subtype was identified in 70 of the 72 carriers, and 69 were ay; the other was ad. Determinant w was present in all 61 that were capable of being typed further, and a23y(w) was twice as common as a11y(w). Antibody to HBsAg (anti-HBs) was found in 514 (18·7%) persons. The prevalence of the HBsAg rose rapidly with age, reaching peak values (5·3%) at 20–29 years, while anti-HBs reached its highest value (42·1%) in older age groups (50–59 years). The frequency of HBsAg was significantly higher in males (3·4%) than in females (1·5%). The percentage of infected persons who become chronic HBsAg carriers (12·3%) was found higher than in other developed populations. It was also found higher in children (25%) than in adults (5·5%) and in males (14·6%) than in females (8·1%). These data indicate that HBV infection in early life is a major risk factor in the development of HBsAg carriers and support the hypothesis that males are more likely to become HBsAg carriers than females.

Serum neutralizing antibodies to polioviruses were titrated in serum samples from 182 police cadets aged 16–18 years before and, in 168 of the cadets, 6 weeks after vaccination with a single dose of oral polio vaccine (OPV). Faecal excretion of poliovirus was also followed. Vaccination histories were obtained and confirmed whenever possible.

Pre-vaccination antibody could not be detected against type 1 in 9·3% cadets, against type 2 in 2·7% and against type 3 in 7·7%. Absence of antibody to at least one virus type was found in 14·3 % of the cadets.

In 93 cadets in whom vaccination histories could be confirmed 40 had received only inactivated polio vaccine (IPV) previously; of these 23% lacked antibody to at least one virus type, and they had less intestinal immunity to a challenge dose of OPV than those previously given OPV. Only two of the cadets known to have had OPV were non-immune – both had received a single dose following full courses of IPV. However, cadets who had received OPV had their last dose of vaccine more recently (average 4.6 years) than those who had received only IPV (all 12 years or more).

The serum antibody response to a single booster dose of OPV, and the faecal excretion of each type of virus after vaccination, showed an inverse relation to the corresponding pre-vaccination antibody concentration. A single dose of OPV did not reliably boost the immunity of those who possessed adequate immunity, and a failure to respond was also observed in a proportion of the cadets with no detectable antibody, mostly in the case of type 3 antibody and particularly if antibody to types 1 or 2 virus was also absent. No evidence was obtained that intestinal immunity could be expected in the absence of detectable circulating antibody.

The reasons for the absence of a serological response to OPV in some subjects are discussed and consideration is given to the practical significance of the findings. It is suggested that reinforcement of polio immunity at school-leaving is important, particularly at the present time when many of those aged 16–18 years will have been vaccinated only with IPV. A single does of OPV is not ideal for this purpose, not only because a small proportion of persons are liable to be left unprotected, but also because failure to produce a reliable boost in persons with adequate immunity at the time of vaccination gives rise to the possibility that they may become susceptible later in adult life.

Type 1 strains of Bordetella pertussis can infect mouse brain and have been recovered as type 1 organisms after death. When introduced into the naso-pharynx of the marmoset, they immediately acquired agglutinogen 2 or 3, and the resulting type 1,2 or 1,3 infection persisted for many weeks.

As in the child, agglutinogens 2 and/or 3 appear to be essential for infection of the marmoset, whereas they are quite unnecessary in mouse brain. A vaccine (extract or whole cell) containing agglutinogen 1 may be sufficient to pass the mouse protection test but it may fail to immunize children. The mouse test is inadequate even for the screening of such extracts.

A schedule for the routine serotyping of strains of Bordetella pertussis based on agglutinin production in mice to the K-antigens has been worked out. Mice have been found as satisfactory as rabbits but far more economical for the production of the very small volumes of serum which are required. Agglutinin production, used in conjunction with direct agglutination, provides definitive information about serotype.

Classification, by agglutinogens, of 634 isolates of Bordetella pertussis collected from 1941 to 1968 in Great Britain demonstrated that a change from a predominantly 1,2,0,4 serotype (75% of those examined during 1941–4) to a predominantly 1,0,3,0 serotype (73% of those examined during 1966–8) occurred sometime after 1953. Furthermore, evidence from the examination of isolates collected between 1941 and 1953 suggests that the change may have been gradual. Isolates of serotype 1,2,3,4 made up 20–30% of the total of our cross-country selection for the periods 1941–4, 1946–9, 1950–3 and 1966–8, but over shorter periods in individual areas the percentage varied from negligible to as high as half of those isolated. Results from other countries show a similar drift towards a 1,0,3 serotype but more often from a 1,2,3 than from 1,2,0 serotype.

The value, in epidemiological studies, of extended information obtained by monospecific typing sera to all six, rather than only two or three agglutinogens, and confirmation of the results by agglutinin production is demonstrated: for instance not all 1,0,3 isolates were identical.

Strains of Bordetella pertussis in which all the organisms contain agglutinogens 1 and 3 or 1, 2 and 4 are easy to identify as serotypes 1,0,3,0 and 1,2,0,4 respectively; and similarly, stable strains of serotype 1,0,3,4 are occasionally found. During repeated subcultures, passage in vivo, and lyophilization and preservation for many years, these serotypes do not change. Mixing 1,0,3,0 and 1,2,0,4 serotypes and culturing them together in vivo and in vitro produces cultures from which organisms of the same two serotypes can be isolated.

In contrast, strains which type as 1,2,3,4 are often a heterogeneous group. We have attempted to classify these as 'stable', 'variable' and 'mixed' cultures. Some strains comprise organisms all of which contain the four agglutinogens and are as easy to type as the strains described above. These we have called 'stable' 1,2,3,4 strains. Other 1,2,3,4 strains are made up of colonies possessing all four agglutinogens, as shown by agglutinin production, but in amounts varying from day to day so that direct typing is inconsistent. These we have called 'variable' 1,2,3,4 strains. The last category, 'mixed', is made up of organisms most of which give rise to stable 1,2,3,4 cultures; a few of the component organisms, however, have one or two of the four agglutinogens missing. The importance of the 'variable' cultures is emphasized for work on apparent change of serotype, e.g. during infection.

Brucella-specific antibodies of different immunoglobulin classes were quantitatively evaluated with respect to their efficiency in serological tests for bovine brucellosis.

IgM reacted more efficiently than IgG1 and IgG2 in both the Rose Bengal plate test and serum agglutination test. The complement fixation test was found to be slightly more sensitive to IgM than to IgG1 and did not react to IgG2. IgM was, however, partly inactivated when heated at 60°C. in the presence of serum.

Exposure of weaned hamsters to an environment contaminated with LCM virus shed by tolerantly infected mice led to short subclinical infections. If infection occurred in early pregnancy, the young appeared normal at birth but their tissues were highly infective. For two to three months their bites and urine were also highly infective. A viraemia did not persist long enough for successive vertical transmissions of the infection to be likely. However, the viruria persisted in most prenatally infected hamsters for at least eight months and under simulated field conditions was a potent virus source for contact infections, leading to further generations of prenatally infected young. In the absence of the natural reservoir host, such long-term carriers could have been a major factor in causing the build-up of infection in colonies of hamsters which, when purchased as household pets, led to a recent spate of human clinical infections in Germany and the U.S.A.

We report the first large-scale outbreak of echovirus 19 infection. It occurred in the north-east of England during the summer and autumn of 1974. The virus was isolated from 268 patients in the region. The infection spread from the urban to more rural areas, reaching a peak in mid-August. Males were affected more often than females in the ratio 1·6:1. Half of the patients were under eight years of age, relatively few were over 35 years. Aseptic meningitis and upper respiratory infections were the commonest presentations, though a wide range of other diseases occurred including gastroenteritis, myalgia, pericarditis, undifferentiated pyrexia, rashes and a syndrome analagous to bacteraemic shock. There was no evidence that the pattern or severity of the disease changed during the outbreak. Infants under the age of six months were more seriously affected than older children and adults. All patients except one made an uneventful recovery. Of the routine tissue culture cells HEp2 and HeLa were by far the most satisfactory for virus isolation.