Sera from 3163 patients were examined for growth-inhibiting and complement-fixing antibody to Mycoplasma hominis. The results were analysed in respect of the age and sex of the patients. Antibodies were found to be uncommon in young people but increased in frequency with age; they were present in old men but were less common in women over sixty-five. Patients attending V.D. clinics and prison inmates had a much higher incidence of antibody than hospital and ante-natal patients. Complement-fixing antibody was approximately three times as common as growth-inhibiting antibody in the sample examined; it was also more common in women than men but the overall incidence of growth-inhibiting antibody was the same in each sex. It was concluded that possibly growth-inhibiting antibody is produced in more severe infections and that it disappears from the serum more quickly than complement-fixing antibody.

1. In streptococcal infection of piglets the causative agent (PM streptococcus) was isolated from the throats of a high proportion of infected animals and from their apparently healthy litter-mates.

2. The PM streptococcus was isolated from the noses of three out of forty-three normal sows. In one sow the streptococcus was also isolated from the throat.

3. Bacteriaemia was induced in piglets up to the age of 17 days by inoculating into the nose and throat broth cultures of the PM streptococcus. Blood cultures were usually positive within 24 hr., and secondary involvement of the joints and meninges frequently occurred during the ensuing few days.

4. Serum taken from piglets 5 weeks after experimental infection and administered subcutaneously protected susceptible piglets against subsequent infection with PM streptococci.

5. The possibility of preventing streptococcal infection in piglets by active immunization of the sow is discussed.

1. A new colicine type (type 15) of Shigella sonnei is described.

2. The epidemiological circumstances associated with its appearance in Edinburgh and Glasgow are summarized.

3. Our indices of reliability as an epidemiological marker are fulfilled by this new type.

During the summer and autumn of 1964, echovirus 4 was found widely distributed in northern Japan; this virus was associated with localized outbreaks of iaseptic meningitis in many regions. The evidence that the echovirus was aetio-logically related to aseptic meningitis was shown by the virus isolation from cerebrospinal fluids and faeces and the serodiagnosis of paired sera in many patients: Age-specific sero-immunity and morbidity rate suggested that echovirus 4 had spread extensively in about 1954. The strains of echovirus 4 isolated in the 1964; epidemic were similar to the prototype strain, Pesascek, in biological characteristics.

A method of controlling outbreaks of streptococcal infection of the upper respiratory tract in communities such as boarding schools is described.

It is suggested that, in a search for carriers, nose and mouth swabs should be taken in place of the customary nose and throat swabs. These swabs will detect those who are dispersing streptococci into the environment, as distinct from the carriers who are not dispersers. It is essential that infections of the skin and ears should also be looked for.

It is recommended that all dispersers, whether nose or mouth positive, should receive sulphanilamide insufflation in both nostrils twice daily for a week, or longer if necessary, without exclusion from school. In addition, penicillin lozenges for 2 days may be recommended for the mouth positives only.

The history is considered to be an important factor in deciding the extent of the initial investigation, and examples are given to illustrate this. When mass swabbing is considered necessary, it is highly desirable that the whole community should be swabbed at the same time, as early as possible in the outbreak. It is also desirable that bacteriological follow-up should be available to check that control has been effected.

The incidence of heat-resistant Cl. welchii in selected classes of a rural population has been investigated. The carrier rate for the general population was low (l·5–6·0%), but persons associated with communal feeding and poor hygienic conditions were shown to have a much higher carrier rate (15·1–25%).

Sex and season had little effect on the incidence of the organism, but among aboriginals the carriage was significantly affected by age. This was probably due to eating habits of the different age groups. The carriage appears to be transient; no persons were shown to be permanent carriers of one strain of heat-resistant Cl. welchii.

The aetiological agent of an epizootic among Common Terns (Sterna hirundo) in South Africa in 1961 was isolated from several sick birds and named Tern virus. It was classified on the basis of antigenic and morphological properties as a strain of avian influenza virus, Myxovirus influenzae A/Tern/South Africa/1961. The strain-specific antigen of Tern virus was unrelated to all known influenza strains with the single exception of Chicken/Scotland/1959 virus and the two viruses may be regarded as variants of the same strain. This relationship raised the interesting epidemiological possibility of the spread of infection between sea-birds and domestic poultry because the Common Tern migrates between Europe and South Africa.

1. Coxsackie A6 virus was isolated in January 1963 from the circulating blood of four children in Suva, Fiji, suffering from fever, lymphadenitis and pharyngitis.

2. Nine strains of the same agent were isolated from Aedes (Stegomyia) poly-nesiensis mosquitoes caught over a period of 2 weeks near or in a village situated among mangrove swamps at the mouth of the Rewa river, in January 1963.

3. No virus was isolated from mosquitoes caught in Suva.

4. A serological survey indicated that Coxsackie A6 infections are common and widespread in Fiji.

Previous estimates of the incidence of glandular fever vary widely. Reasons for this are suggested. The present investigation was designed to show the incidence of cases of glandular fever presenting to doctors in certain general communities near Portsmouth in 1962–63.

The overall incidence in these areas during the year was found to be 38 per 100,000 population; this amounts to an average of one case annually in a medium-sized general practice. The incidence appeared to be lowest in a council housing estate. Glandular fever was not common in children, although it was frequently diagnosed on clinical grounds.

The ways in which cases of glandular fever might be missed in a survey such as the present one are discussed. It is thought that many patients may become ill but not consult their doctors. Truly subclinical glandular fever, however, is thought to be infrequent.

We studied the incidence of staphylococcal infection in a thoracic surgery ward which consisted of a number of separate rooms, and inquired whether the subdivision of the ward was responsible for the unusually low sepsis-rate.

The airborne dissemination of Staphylococcus aureus from one room to another appeared to be little less than that in an open ward; but the total number of Staph. aureus in the air was very low.

Most of the patients received prophylactic antibiotics. The nasal carrier-rate of Staph. aureus by patients fell greatly during their stay in the ward. There was a progressive disappearance of sensitive organisms and little acquisition of multiple-resistant organisms.

When there are urgent clinical grounds for the lavish use of antibiotics, the dangers appear to be reduced by effective segregation of the patients from each other.

The sensitivity of quantal and graded responses to mouse-adapted bluetongue virus for the detection of neutralizing antibody was compared using probit and rankit analysis. The graded response, based on survival times, allowed the demonstration of antibody in highly dilute serum, in which antibody was not detected by the quantal response recording percentage death.

Quantal responses to bluetongue virus variants were compared with theoretical dose-response curves constructed according to the Poisson distribution for the random variation of virus particles in inocula. Of these theoretical curves the first term in the Poisson distribution gave the best approximation to the experimental data but the fit to normal distribution curves was better. The quantal responses to bluetongue virus did not appear to reflect the random variation of one-or-more infectious virus particles in inocula.

In graded responses to bluetongue virus, a rectilinear relationship was observed between reciprocal harmonic means of survival times and log virus dilutions.

Sera from healthy Greeks, Liberians and East Africans were tested for dye test and direct agglutinating toxoplasma antibodies. At a titre of 1/16 or more 137/228 Greeks, 84/133 Liberians, 2/13 Bondei infants, 3/7 Bondei adults, 3/9 Masai infants and 20/43 Baganda adults gave a dye test positive result. This confirms the wide-spread occurrence of this infection.

1. Faeces from apparently healthy Bantu children from schools in Soweto township near Johannesburg were examined eight times at fairly regular intervals over a period of 1 year.

2. Only fifty-five children were present for all eight investigations and, of these, 36·4% yielded salmonellae and 9·1% shigellae. Taking the group as a whole, 26·2% of the children had salmonella infections and 6·2% shigella infections.

3. Parasites were shown to be present in sixty-four of the 130 children during the period of the investigation.

4. As in other surveys, there were more isolations in summer than in winter.

5. S. labadi and S. typhimurium were most frequently isolated, with the group B–E constituting 75% of the total isolations. S. typhi, S. paratyphi A, B and C were not found.

6. Water supplied to each house by the Johannesburg municipality was of good quality, yet it did not affect the incidence of salmonellosis and shigellosis.

7. In spite of better socio-economic conditions the incidence of salmonellosis is comparable to the two previously mentioned surveys. These findings indicate a lack of instruction on personal hygiene and the importance of public health measures.

Bluetongue virus was found to be resistant to ether, chloroform and sodium deoxycholate under a variety of conditions but sensitive to treatment with trypsin. The virus had a narrow zone of pH stability between pH 6 and 8 in Michaelis buffer. Below pH 6 bluetongue was irreversibly inactivated within 1 min. at 37° C. In many of its characteristics, bluetongue virus appears to be closely related to the reoviruses.

A high incidence of drug resistance, mostly of the infective type, was found amongst strains of Escherichia coli isolated from human beings suffering from neonatal diarrhoea, calves and lambs suffering from neonatal diarrhoea or bacteraemia, pigs suffering from neonatal or post-weaning diarrhoea or bowel oedema and from fowls suffering from ‘coli-septicaemia’. The strains from the human beings, pigs and fowls, and those from calves and lambs suffering from bacteraemia, belonged to serotypes generally accepted as being pathogenic for these species.

Complex drug-resistance patterns were a common feature, particularly amongst the human and calf strains, some being resistant to six drugs. Only two drugs, polymyixin and nalidixic acid, were active on all the strains.

The incidence of drug resistance amongst pig strains was twice as great in those isolated in 1965 as in those isolated in 1960–62; neomycin and furazolidone resistance was found amongst the 1965 strains but not amongst the 1960–62 strains.

Infective resistance was easily demonstrated; tetracycline resistance was transferred from one tetracycline-resistant strain of E. coli to 37 of 38 tetracycline-sensitive strains at the first attempt.

Most ampicillin, streptomycin, tetracycline, chloramphenicol, neomycin and sulphonamide resistance was of the infective type; the furazolidone resistance in all of eight strains studied was not shown to be infective.

In the experiments to demonstrate the presence of infective resistance the level of drug resistance was usually found to be the same in donor and recipient strains.

Cattle infected with FMDV strains of different epizootiological origin developed a carrier state which persisted in the majority of animals for several months. Fluid samples taken from the oesophageal/pharyngeal region were assayed for infectivity by plaque counts on BHK monolayer cultures and by mouse inoculation. With one strain of virus, infectivity levels of up to 1000 pfu/ml. were recorded for several weeks after infection but in general the virus content of samples was below 50 pfu/ml.

The sites of virus persistence and multiplication were identified by titration of suspensions of mucosae and epithelia taken post mortem. Virus was recovered from 41 of 54 cattle killed 14–196 days after infection. The chief sites of virus multiplication based on the frequency of virus recovery and infectivity titres were the dorsal surface of the soft palate and the pharynx. Virus was recovered less frequently from the ventral surface of the soft palate and the glosso-epiglottic space and only occasionally from the tonsillar sinuses, tonsils, tongue, trachea and oesophagus. No virus was detected in the turbinates or in the epithelium of the urinary bladder.

1. An incomplete field study in Lincolnshire, England, suggested that toxoplasmosis might be transmitted from pig to man by mosquitoes. Although the results were inconclusive they suggested the experimental work recorded in this paper.

2. Trophozoites of the Beverley strain were obtained in increased yield from the peritoneal fluid of Mastomys treated with hydrocortisone. Cysts were obtained in increased yield by passage of the brain of Sigmodon into laboratory mice.

3. Four species of mosquitoes were fed through a membrane or on sucrose solution on media containing either cysts or trophozoites of Toxoplasma gondii. In some experiments blood was added to ensure passage of the feed to the mosquito stomach, in others it was excluded so that at least part would pass to the crop.

4. A spurious ‘cyst’ resembling but distinguishable from Toxoplasma was noted in the homogenate of mouse brain.

5. In no instance did mosquitoes retain infectivity as demonstrated by injection into mice, beyond the third day, but since experiments were not carried on beyond the fourteenth day the existence of an occult form cannot be excluded.

Reactions to the pertussis component of the original commercial batches of quadruple vaccine against poliomyelitis, diphtheria, tetanus and pertussis (Quadrilin, Glaxo Laboratories) gave some cause for concern. Severe reactions were found to be more common in infants under 6 months of age than in older infants.

A modified quadruple vaccine, which has been used in N. Ireland since October 1964, was found to give rise to significantly fewer and milder reactions. This vaccine when given in three doses separated by intervals of 6–9 weeks and 6 months to fifty-eight infants most of whom were 6–7 months of age at the start of immunization was found to give a satisfactory immunological response.

A fermentation-inhibition test for the measurement of growth-inhibiting anti-body to acid-producing mycoplasmas was performed in microtitre plastic plates. M. pneumoniae, M. fermentans and the Negroni agent were selected for study. Antibody could be titrated since specific antiserum inhibited mycoplasma growth and the concomitant production of acid, thus preventing a change in colour of phenol red which was incorporated in the growth medium. It was essential to use unheated horse serum as a component of the growth medium. The inhibitory effect of specific antiserum was much decreased when the horse serum was heat-inacti-vated, indicating the need for a heat-labile accessory factor. The additional use of unheated guinea-pig serum was essential for demonstrating the growth-inhibiting effect of specific antiserum on the Negroni agent. The test was reproducible, specific and sensitive. Sixteen-fold or greater antibody rises were demonstrated in paired sera from volunteers infected with M. pneumoniae. Tests with ninety-five random adult sera showed that 22% had antibody to M. pneumoniae at a titre of 1/5 or more and 13–5% had antibody to M. fermentans.