The results of routine bacterial and viral studies on 483 patients with whooping cough, investigated at one hospital over a five year period are presented. The possible role of respiratory viruses in the aetiology of the disease is discussed.

Sera from 218 of 1574 (14%) small mammals collected in the Yukon Territory between 14 May and 13 August 1972 neutralized a Yukon strain of California encephalitis virus (snowshoe-hare subtype). These included 133 of 319 (42%) snowshoe hares (Lepus americanus), 84 of 1243 (7%) ground squirrels (Citellus undulatus) and 1 of 12 (8%) tree squirrels (Tamiasciurus hudsonicus). California encephalitis virus (snow-shoe hare subtype) was isolated from four pools of unengorged Aedes communis mosquitoes collected near Whitehorse (61° N., 135° W.) and on one occasion each from pools of the same species collected at Hunker Creek (64° N., 138° W.) and at mile 125, Dempster Highway (66° N., 138° W.) during July 1972. Replication of a Yukon strain of California encephalitis virus was observed in wild-caught Culiseta inornata and Aedes canadensis mosquitoes after intrathoracic injection and holding at temperatures of 80°, 50° and 40° F.

Pork was cured by (a) the Wiltshire method and (b) a hygienic sweet cure process. Representative samples of both bacons were inoculated at ‘low’ density (103 organisms/g.) and ‘high’ density (106 organisms/g.) with a toxin-producing strain of Staphylococcus aureus, ‘High’ and ‘low’ density samples of both bacons were each stored at 5° C. for 42 days and 15° C. for 21 days.

Results indicated that the test organism at high inoculum density grew slowly in both bacons at 5° C. The organism survived at 5° C. in both ‘low density’ bacons. At 15° C. the test organism grew; growth being more pronounced in the ‘hygienic’ than in Wiltshire bacon.

Lactose tryptone ricinoleate broth (0·3% lactose, 2% Oxoid tryptone, 0·1% Na ricinoleate; pH 7·1) was found to be as good as the currently recommended combination of lactose ricinoleate broth and tryptone water for the detection of Escherichia coli in the positive tubes of presumptive coliform counts.

An electronic particle counting device is described, based on a constant-temperature hot-wire anemometer probe. The device has found application in tracing the motions of droplets and measuring their concentration within ventilated areas when subjected to different types of ventilation. In this way the effectiveness of various systems may be determined.

The socio-economic status of 80 patients with infectious mononucleosis was compared with the socio-economic distribution of the general population in the same area of south-west London. An excess incidence of infectious mononucleosis was observed among subjects from upper socio-economic groups. A possible relationship between this observation and the epidemiology of the Epstein—Barr virus is discussed.

Two hundred and sixty strains of Pseudomonas aeruginosa were isolated from patients of the Asaf Harofe Government Hospital. The strains were typed by phage technique and 64 of them were also typed according to pyocine sensitivity. The two methods proved complementary, and reduced the number of untypable strains. Phage typing was performed with both routine test dilution (RTD) and more concentrated phage suspensions. The most reliable results were obtained at 100 RTD.

The dispersal of Staphylococcus aureus from burned patients, the relation between nasal carriage by the staff and exposure to airborne Staph. aureus, and the transfer of Staph. aureus-carrying particles within the ward have been studied. The dispersal of Staph. aureus from burned patients was correlated to the size of the burn wound. The median values varied from 21 c.f.u./m.2/hr. for patients with small burns to 453 c.f.u./m.2/hr. for extensively burned patients. The size of the dispersed particles appeared to be smaller than that usually found in hospital wards. Carriage of nasal strains by the staff was correlated to the air counts; the number of patient sources did not seem to be of great importance. The transfer of Staph. aureus within the ward was at least 6 to 20 times that which would have been expected if transfer was due to air movement only.

Serological investigations were carried out on 147 patients with Paul—Bunnell positive infectious mononucleosis (IM) from the general population. All possessed antibody to the Epstein—Barr virus (EBV) and 63% showed serological evidence of recent infection. Contacts of 132 patients, 306 in all, were followed serologically; within 6 months of the index cases' illness twenty one contacts developed evidence of EBV infection or re-infection and of these five developed overt IM. The secondary attack rate of EBV infection among susceptible contacts was at least 19%; the corresponding figure for clinically apparent IM was 6%. EBY antibody prevalence among patients' siblings was significantly lower than among age-matched controls, suggesting that cases of IM come from families with a lower than normal previous experience of the virus. Of thirteen patients with persistently Paul—Bunnell negative ‘glandular fever’ four had serological evidence of recent EBV infection and two had probable cytomegalovirus mononucleosis. Recent EBV infection may have been associated with the illnesses of five of the remaining patients.

Cultures of Staphylococcus aureus showing unstable resistance to kanamycin, streptomycin, lincomycin and penicillin have been preserved by drying. Particular attention has been paid to organisms showing linked resistance to pairs of these antibiotics. Recoveries of viable cells from the desiccates was high and the proportion of resistant and sensitive cells was maintained both during storage and during heating. The preservation of the organisms on ceramic beads stored in air over silica gel promises to be an effective and convenient method for maintaining staphylococcal desiccates during studies of unstable antibiotic resistance.

The contamination of gowns and uniforms worn in a burns unit and the transfer of patient's staphylococci by means of nurses' uniforms was investigated. The median values of staphylococci found on gowns and jackets worn during a routine nursing procedure were 3·0 × 104 and 1·4 × 103 respectively. From the results of model nursing experiments it appeared as if the fraction of staphylococci transferred from a patient's room to the air in a receiving room was 4 to 10 times less when protective gowns were worn than when no gowns were worn. The corresponding transfer directly to the model ‘patient’ was 100 times less. The protection afforded by a gown seemed mainly to be due to protection against contamination of the uniform worn underneath when nursing a burned patient. The discrepancy between the transfer of an airborne particle tracer and Staph. aurats-carrying particles earlier found in the ward could be explained by the dispersal of Staph. aureus from nurses' clothing.

In correspondence arising out of our recent paper (Wyon, Andersen & Lundqvist, 1972), interest has been expressed in the relative widths of the comfort zones obtained by using the Bedford 7-point scale and our proposed dial-vote scale. It was possible to make a direct comparison on our original data, using votes registered simultaneously on the two scales at the end of each hour of exposure. Air temperature rose only slowly towards the end of each hour, and the comparison is probably valid also for steady-state conditions. The proportions voting ‘too hot’ (Bedford categories 6, 7, dial vote >66·6%) and ‘too cold’ (Bedford categories 1, 2, dial vote <33·3%) were derived and probit analysis was performed (Pinney, 1947). Only responses obtained from the 36 female subjects are considered, for very few males were too cold in the temperature range 23–29° C The results are shown in Fig. 1, using the same presentation as in fig. 7 of the original paper. No statistically significant differences could be shown between the pairs of regression lines, either in terms of their slopes or median values. However, the tendency is clearly for the dial-vote method to yield if anything a rather narrower and lower comfort distribution, and hence a narrower zone of comfort, however defined. This in spite of a marked ‘comfort zone’ occupying as much as one-third full scale. As pointed out in our original paper, the comfort zone yielded by either scale should be regarded as a zone of tolerance and not as a zone of ideal comfort.

Forty-five samples of unsliced, cooked, ready-to-eat meats on sale in retail premises and supermarkets were examined. Thirty-six (80%) had Escherichia coli I and 21 (47%) had coagulase positive staphylococci in numbers ranging from 1 to > 1000/100 cm.2. Twenty-one samples contained Clostridium spp. in numbers from 1 to > 100/100cm.2. Of the 45 samples tested, 11 (factory-produced) and 7 (home-produced) were examined after cooking but before being offered for sale. Cooked hams were contaminated after handling in a factory, as were samples of canned corned beef after sale and exposure for 24 hr. Some sources of contamination were: (a) raw beef, (b) factory and shop surfaces and equipment, and (c) workers' hands. Curing brines used in retail shops and supermarkets to produce corned beef were a potent source of contamination. The effect of holding cooked meats at ambient temperature on their spoilage (22° C) and food-poisoning (37° C) microflora was demonstrated.

In laboratory experiments the acute eye irritation produced by exposure to tap water was not significantly increased when chlorine compounds were added to the water at concentrations of 1 mg./l. The greatest irritation was produced by 2 mg. Cl2/1. as NH2C1. The addition of NaCl at concentrations above about 0·5% abolished the irritant effect of tap water, and prevented irritation even when 1 mg. Cl2/1. was present.

In a field experiment involving two swimming baths, one with fresh and the other with saline water (0·5 % NaCl), eye irritation in the saline bath was significantly lower than in the freshwater bath only when the swimming time did not exceed 30 min.

A significant proportion of a consignment of branded Parma Ham was found to have ‘blown’ tins; the associated bacterial flora was therefore investigated. No Salmonella or Shigella were found. Clostridium welchii type A and Clostridium bifermentans were isolated in moderate numbers only from enrichment cultures of the ham. Staphylococcus spp. and coryneform bacteria were obtained from all tins and Group D streptococci were present in a few. No food-poisoning cases were associated with this ham.

The virulence of T-mycoplasmas for cattle was tested by examining their ability to produce mastitis in cows. It was found that both virulent and avirulent strains of T-mycoplasmas can be isolated from cattle. All of four strains from pneumonic calf lungs and a strain from a case of bovine kerato-conjunctivitis caused mastitis but only two of four strains isolated from the urogenital tract of cows were virulent. None of the human, simian or canine T-mycoplasmas examined were able to cause mastitis in cattle. However, a bovine strain was found to be capable of causing mastitis in goats. Virulent and avirulent strains from the same and different species contain common antigens detected by the metabolic inhibition test. Pathogenicity could not be shown to be characteristic of any particular serotype. The possibility is raised of some species barrier being responsible for the inability of non-bovine strains to infect cattle.

In the villages of Fiji, apart from Viti Levu, rubella is a disease occurring solely in widely spaced epidemics. Some villages may not be infected for over 20 years and will then contain substantial numbers of susceptible women of child-bearing age.

Evidence is produced that haemagglutination-inhibiting (H.I.) antibody to rubella is very long lasting in Fijians. The infectivity of the virus is discussed and it is suggested that, on the average, 50% of susceptibles are infected in a Fijian village during a rubella epidemic, but there are large variations.

A study of Sonne dysentery infections in 19 primary and 11 secondary day-schools and 4 day-nurseries has been made over a period of 18 years in an urban area. Measures were taken throughout to try to prevent and control outbreaks. Sonne dysentery was not endemic in the school population and, even at times of high incidence, epidemics were localized within a few of the primary schools, usually in the spring or autumn terms. Incidence rates of Sonne dysentery were highest in primary schools with large infant departments and in nurseries. Secondary schools entirely escaped outbreaks.

The co-operation of head teachers was engaged for all precautionary measures in schools. A policy of immediate exclusion of suspected and infected children was useful in preventing and controlling school epidemics of dysentery. Toilet hygiene was often poor in schools with outbreaks, and this was found to be a profitable field for applying control measures. Infected kitchen workers were only occasionally involved.

Recommendations are given in the light of this study, and some reference is made to the more difficult problem posed by dysentery outbreaks in day-nurseries, where temporary closure may be the best policy. It is important that responsibility for infectious disease control in schools be clearly delineated in the reorganized health services of 1974. Teachers can play an important part in limiting infection.

A one-year epidemiological investigation was made in an isolation ward for burned patients. The transmission of Staphylococcus aureus was mainly studied. In spite of the design of the ward the cross-infection rate was high. In all, 49 of 69 patients were infected 114 times. Twenty-six of the strains causing infection were found in a patient only, 10 in a member of the staff only and 23 in both patients and staff the week before they caused a new infection. There were three epidemic outbreaks caused by three strains of Staph. aureus all belonging to phage group III; one was resistant to methicillin. Environmental studies with settle plates showed that the number of staphylococci dispersed by a burned patient was often very high. In 8% of the observations in occupied bedrooms the air count of Staph. aureus was more than 1800 col./m.2 hr. However, the counts of Staph. aureus in the corridor and service areas were low. This seems to indicate a rather good protection against airborne transfer of bacteria. Other routes of infection were probably of greater importance.