A large outbreak of streptococcal sore throat in a Royal Air Force Training Camp resulted in five cases of rheumatic fever among the 16- to 18-year-old apprentices, and one case in a 33-year-old airman. The most prevalent type of group A streptococcus isolated from throat swabs was M-type 5 and there was serological evidence that at least four of the rheumatic fever (R.F.) cases were due to this type.

Among the patients with uncomplicated throat infection the anti-streptolysin O (ASO) and anti-deoxyribonuclease B (anti-DNAase B) responses were in general rather low, even where there was evidence of protective antibody against type 5. However, a combination of the results of the ASO and anti-DNAase B tests gave an estimate of the extent of streptococcal infection 15–25% higher than did either test alone.

The titres of antibody to M-associated protein (MAP) were ≥ 60 in all the r.f. patients, and in about 50% of the other patients with ASO titres ≥ 200. This figure is unusually high compared with data from several other outbreaks of streptococcal infection due to different serotypes and also greatly exceeds comparable figures for cases of sporadic sore throat and acute glomerulonephritis.

Mice given an intraperitoneal injection of 0.5 mg. Corynebacterium parvum (dry weight) before vaccination with heat-killed (HK) or acetone-killed (AK) Salmonella typhimurium vaccine and later challenged intraperitoneally with S. typhimurium strain 1566, showed a statistically significant increase in mortality when compared with mice that had received only C. parvum but no vaccine. They also showed a higher mortality rate than mice receiving only HK or AK vaccine or mice that had received no vaccine before challenge. Prior administration of C. parvum to mice that are vaccinated with HK or AK vaccine appears to make them more susceptible to an intraperitoneal challenge with S. typhimurium. This was more apparent with HK vaccine than with AK vaccine.

The sera of 200 Chinese adults recently immigrated to Canada from Hong Kong were examined for antibodies to Toxoplasma gondii by the indirect fluorescent antibody technique. It was found that the total incidence was 18·0%. This is significantly lower than that of the indigenous population of the same age groups in this area.

The relative susceptibility of VERO cells and primary rhesus monkey kidney cells to 47 prototype strains of human enteroviruses is described. Of these strains, types 4, 14, 16, 17, 18, 21, 31 and 34 and Coxsackie virus A 9 failed to cause CPE in the VERO cells whilst only one, echovirus type 34, failed to cause CPE in the monkey kidney cells.

A comparison is given of the efficiency of the two cell cultures for enterovirus isolation from clinical material. Results show that VERO cells are as useful as primary monkey kidney for the isolation of Coxsackie B viruses but less satisfactory for isolating echoviruses. They are satisfactory for the isolation of single types of poliovirus and appear to be more satisfactory than primary monkey kidney cells for the isolation of mixtures of polioviruses. The identification of enteroviruses by neutralization tests in VERO cells is successful.

Guanidine hydrochloride selectively inactivated both the biological activity and the immunogenicity of the haemagglutinin of influenza A/X-7 (H0N2). The residual neuraminidase was fully active biologically and immunologically. The reverse was observed with influenza B/ROB; with this virus the haemagglutinin was resistant, and was immunogenic; while the neuraminidase was selectively inactivated, and was not immunogenic.

An attempt was made to sterilize a newly erected building of approximately 1200 m.3 (43,000 ft.3), specially designed for the breeding of specific-pathogen-free mice, rats and guinea-pigs. Two methods of treatment were used, namely an ampholytic surface acting biocide/formaldehyde aerosol followed after 2 days by formaldehyde vapour. Bacteriological examination was made of 100 sites in the animal rooms, staff quarters and general service area before and after both treatments. Identification of the bacteria isolated was based upon their morphological appearance on laboratory media incubated aerobically and their reaction to Gram's stain. Organisms were isolated from 72/100 sites before treatment, from 50 sites after the first treatment, and from 13 sites after the second treatment. The bacteria that survived both treatments were of several species.

The air from a house and garden in a rural area has been sampled and the size distributions of the airborne particles have been determined. The particle concentrations are shown to be generally higher indoors. Changes in the particle concentration during various activities in a small room have been shown to be greatest for particles larger than 3 μm. diameter. Stereoscan microscopic observation has shown that many of the airborne particles in rooms and some from those in outside air appear to be scales of desquamated skin. The presence of protein in many of these particles complements the microscopic observations.

Ventilation of vessels varying widely in size was found to preserve the toxic effect of open-air factor(s). There was a correlation between the minimum rates of ventilation required and the ratios of the surface area of the vessels to their volumes. The data obtained allowed an estimate to be made of the diffusion coefficient of open-air factor(s) and gave an indication that the molecular weight range of the open air factor(s) was from 50 to 150.

The air of loose-boxes holding pigs affected with swine vesicular disease was sampled for virus. In the multistage impinger virus to a titre of 102·6 TCID50 was associated with particles greater than 6 μm., 101·6 with particles 3–6 μm. and 101·4 or less with particles less than 3 μm. In the noses of workers in contact with the pigs for periods not less than 5 min., virus to a titre of 102·4 TCID50 was found. Virus was recovered from the air for 2–3 days during the disease and maximum titre in pigs infected by injection or by contact occurred on the second to third day after generalization of the lesions. The amounts of virus were about 160-fold less than those recovered from pigs affected with foot-and-mouth disease, and the quantity and time of excretion suggest that the source of swine vesicular disease virus in the aerosol may be from the lesions and skin rather than from the respiratory tract.

A total of 2525 strains of Escherichia coli were isolated from the faeces of 33 mothers, the faeces of their babies and the mucus extracted from the babies' mouths after delivery. Of these strains 1832 could be O-serotyped with 150 O antisera. E. coli were isolated from 28 babies and the same serotypes as were found in their mothers were found in 22 of them. E. coli was isolated from only 14 of the mucus specimens but in 12 of these at least one of the serotypes present was subsequently found in the babies' stools.

The mean isolation rates of salmonellas from the mesenteric lymph nodes and faeces of healthy mink were 16·7% of 618 animals from three farms and 3·9% of 772 animals from four farms respectively. Salmonella senftenberg was the most commonly isolated serotype. S. typhimurium, S. dublin, S. livingstone, S. menston, S. enteritidis, S. bredeney and S. infantis were also seen.

The prevalence of salmonellosis in 316 dead mink from 12 farms was 0·6%.

The epidemiological aspects are discussed.

Three purified cell-wall glycoprotein antigens, a, b and c, sensitive to sodium periodate and resistant to pronase, were extracted from mycelium of Micropolyspora faeni with aqueous phenol or trichloracetic acid. Pronase-sensitive, sodium periodate-resistant protein antigens were extracted from mycelium with aqueous phenol. Immunoelectrophoresis was a critical method of assessing purity of preparation.

Antibodies to glycoprotein antigens only occurred in clinically defined cases of farmer's lung disease, whereas antibodies to protein antigens also occurred in symptomless farmers. Precipitins to a occurred in all cases of farmer's lung disease, and this antigen was isolated and purified.

Fractionation of pooled sera from cases of farmer's lung disease showed that precipitins were IgG globulins, whereas latex-agglutinating antibodies were IgG, IgA and especially IgM globulins. It is suggested that farmer's lung may involve a cytotoxic type II reaction, in which glycoproteins adsorbed to tissue cells react with IgG, IgA and IgM immunoglobulins in the presence of complement, causing cellular damage.

Normal ferrets did not produce serum antibody following immunization with 200 i.u. of inactivated A/Hong Kong/68 influenza virus vaccine and were found to be susceptible to subsequent challenge infection with A/Hong Kong/68 virus. High titres of virus were recovered from nasal washings collected 3 days after infection, serum antibody was produced, increased nasal protein was detected and HI antibody was detected in nasal washings. Ferrets infected with influenza virus A/PR/8/34 7 weeks before immunization with inactivated A/HK/68 virus did, however, produce serum HI antibody to A/HK/68 virus. This antibody conferred partial immunity to challenge infection with A/HK/68 virus, as shown by decreased titres of virus in nasal washings and reduced levels of nasal protein. Previous infection of ferrets with influenza virus B/Ann Arbor/66 did not result in the production of serum antibody to A/HK/68 virus following immunization with A/HK/68 vaccine and the animals were completely susceptible to subsequent challenge infection with A/HK/68 virus. Differences in the amount of nasal protein and nasal antibody produced after A/HK/68 infection were also found in ferrets previously infected with either A/PR/8/34 or B/AA/66 virus, compared with normal ferrets.

The waters of one indoor bath and three outdoor baths were examined once an hour during 3 days (bath 1) or 6 days, for available chlorine, redox potential, permanganate number, ammonium, nitrate and total nitrogen, total bacterial count at 22° C., total bacterial count at 37° C. and faecal coliform bacteria. The weather, number of swimmers and the chlorine gas addition were continuously registered, and the pH was checked a few times at each bath. In bath 1, an indoor pool with aluminium sulphate precipitation about once a week and with sand filters back-washed every 2 days, less than 10 bacteria/ml. were found in all samples. In bath 2, an outdoor pool with aluminium sulphate precipitation twice a week and with sand filters back-washed twice a week, also few bacteria were found. In bath 3, an outdoor pool with only filtering through sand filters back-washed about every 14 days, high bacterial counts were found every day except the first, when the filters had been newly back-washed. In bath 4, an outdoor pool with only filtering through sand filters back-washed about once a week, high bacterial counts were found now and then during the first 4 days when the weather was warm, but few bacteria were found the last 2 days when the weather was cold and windy, and there were few swimmers.

Values from different analyses on the same sample showed relatively good correlation between the redox potential and the free available chlorine. In bath 3 both the redox potential and the available chlorine were weakly correlated to the bacterial count, but in bath 4 there was no such correlation. No other factors were well correlated with the bacterial count either.

The bacterial counts at 22° and 37° C. were of the same order. No faecal coliforms were ever found. Use of these bacteria as indicator organism in swimming pools is criticized.

The method of using certain minimum values of the free available chlorine as guarantee for a satisfactory bacteriological quality of the swimming pool water is also questioned. The degree of purity of the water is fundamentally connected with the disinfecting power of the available chlorine.

Use of certain minimum values of the redox potential, according to these investigations, seems to be a method of somewhat greater accuracy. Provided that the methods of precipitation are performed correctly and filters are being back-washed often enough, then an automatically registering redox potential device, perhaps connected to the chlorine gas pump, ought to constitute a good control of the hygienic quality of a swimming-pool water. This must, however, always be completed by bacteriological examinations, preferably made at high bathing load.

Nasopharyngeal secretions were taken during the acute phase of illness from 66 infants and children admitted to hospital with lower respiratory tract infections. Second secretions were taken, after an interval of 7 days, from 33 of these patients. A significant increase in neutralizing activity to R.S. virus was demonstrated in the nasopharyngeal secretions of patients in response to severe R.S. virus infection. Seventeen out of 25 patients (68%) with R.S. virus infections developed a rise in secretory neutralizing titre, compared with only 1 out of 8 patients (13%) with respiratory infections not involving R.S. virus.

A high titre of secretory neutralizing activity was found more often in the acute phase of illness in patients with R.S. virus infections, especially bronchiolitis, than in patients with respiratory infections not involving R.S. virus. Fifteen out of 34 patients (44%) with R.S. virus bronchiolitis were found to possess a neutralizing titre of 1/4 or more in their first secretions, compared with 4 out of 12 patients (33%) with R.S. virus infections other than bronchiolitis and 3 out of 20 patients (15%) with respiratory infections not involving R.S. virus.

A quantitative analysis of the immunoglobulins present in the secretions indicated that IgA was the only immunoglobulin consistently present at a detectable concentration. The geometric mean values of IgA, IgM and IgG in the secretions examined were found to be 22·3, 4·3 and 5·3 mg./lOO ml. respectively.

The neutralizing activity against R.S. virus, present in the secretions, was shown to be due to specific IgA antibody. This was accomplished by removing the neutralizing activitv in two secretions bv absorotion with anti-IaA serum.

BHK-21 cells and HeLa cells were as sensitive as irradiated McCoy cells for titrating both fast- and slow-growing strains of TRIC agents. BHK-21 cells were as efficient as irradiated McCoy cells for isolating TRIC agents from trachoma and from the genital tract of patients with non-gonococcal urethritis. More inclusions were formed in BHK-21 than in irradiated McCoy cells.

The neutralizing activities of fowl, rabbit and mouse antisera prepared against TRIC agents were enhanced, in some cases over a 100-fold, by the addition of antiserum against the appropriate IgG. Significant non-specific inactivation of the organisms was observed in the absence of antiserum against TRIC agents, in reaction mixtures containing normal serum and antiserum against IgG. Since the extent of this inactivation showed a prozone, control tests with dilutions of normal serum equivalent to the full range of dilutions of the antiserum tested are necessary to show that enhancement of neutralization is specific.

Pigs exposed to relatively small amounts of virus by intradermal inoculation of the feet or by skin scarification developed clinical disease. Large amounts of virus were recovered from samples taken from the nose, mouth, pharynx, rectum and the prepuce or vagina during the first week of infection and smaller amounts during the second week. Virus was recovered from the faeces of most animals 16 days after infection and from one animal for 23 days. Pigs in contact with inoculated animals were killed at intervals before the appearance of clinical disease. The distribution and amounts of virus in various tissues indicated that infection had most likely gained entry through the skin or the epithelia and mucosae of the digestive tract. Some pigs acquired subclinical infections in which no virus excretion was detected and no transmission of infection to susceptible pigs took place over a period of 5 weeks.