Airborne smallpox virus has been recovered in an isolation hospital using an adhesive surface sampling technique in the presence of very low aerosol concentrations. Previous work in this field is reviewed. Successful recovery of airborne virus depends on sampling large volumes of air with a suitable sampler and thorough investigation of the whole sample taken for the presence of viable virus. More information on the characteristics and behaviour of airborne smallpox virus is needed in particular with regard to the future design and siting of smallpox isolation units.

Virological examination of 385 patients with suspected heart disease and 26 with Bornholmdisease over a period of 6 years suggested that Coxsackie group B virus infections were associated with at least half the cases of acute myocarditis and one third of the cases ofacute non-bacterial pericarditis. Complement-fixation tests revealed only a few cardiac illnesses associated with other infections (influenza and Mycoplasma pneumoniae). No evidence of infection was found in chronic cardiac disease.

A simplified method for the detection of rubella-specific IgM in sera was developed involving HAI tests on only one fraction from a sucrose density gradient with and without treatment with 2-mercaptoethanol (2 ME). Slight trailing of IgG into the IgM fraction was shown to occur in patients with high titres of both IgG and IgM, but this could be detected by the 2ME treatment and did not affect the results.

By this test, rubella-specific IgM was found in all of 54 patients with a rash and a rise of rubella HAI antibodies. When the antigen and serum were incubated for 1 hr. before adding the RBC, specific IgM was found in all 51 sera taken between 5 and 40 days after onset, and in about half the sera taken between 42 and 77 days, but in none of 16 people known to have possessed rubella antibodies at least a year previously. When antigen and serum were incubated for 18 hr. before adding the RBC, specific IgM was found in all of 21 sera taken between 2 and 49 days after onset, and in 6 of 11 sera taken between 50 and 117 days, but not in 9 people known to have possessed rubella antibodies at least a year before. The method has been found to be very useful in detecting recent rubella among patients in early pregnancy.

The results are presented of testing untreated producer–retailer herd milk samples for the presence of Brucella abortus during the period 1965–1972 in the North Lancashire region.

There was a steady decline in the incidence of infected herds from 22 % in 1965 to 12% in 1971. A sharp fall to 5% in 1972 suggests that the introduction of the Brucellosis Incentives Scheme and the eradication programme has helped to reduce the practice of selling brucella-infected cattle in the open market which was prevalent in the period 1965 to 1970.

This practice of selling brucella-infected cattle may also be a prime factor in the changing pattern of distribution of the biotypes of B. abortus which was observed during the period 1965 to 1970.

A comparison of the two areas in the region show that the incidence of herd infection was always greater in the area containing flying herds than in the area in which self-contained herds predominated.

The potentiality of calciferol (alone and combined with warfarin) for the control of commensal rats and mice has been examined in the laboratory. Nearly all animals fed on 0·1% calciferol for 2 days died. Though illness usually reduced food intake after the first 24 hr. there was no sign of aversion to the poison at 0·1 % – which is considered to be the lowest concentration suitable for use against Rattus norvegicus, R. rattus and Mus musculus in the field. There was some indication that resistance to warfarin in R. norvegicus may be correlated with susceptibility to calciferol. Toxicity tests with calciferol combined with warfarin indicated an additive effect between the compounds. No evidence for synergism was found however, although elsewhere there is some evidence for this.

Seven hundred and sixty-eight patients were seen and tested at frequent intervals after transfusion of whole blood. Eight patients were judged to have developed icteric or anicteric post-transfusion viral hepatitis, an incidence of 1%. Five were icteric and four of these were hepatitis B antigen (HB Ag) positive; two of these four died. One of the fatal cases and one non-fatal HB Ag positive case had received HB Ag positive blood. Two other antigen-positive patients had received blood or plasma or both which had not been tested for antigen.

Thirty-five patients showed conspicuous or sustained elevations of alanine transaminase without clinical features of hepatitis.

Four were positive for HB Ag but had not received antigen positive blood.

Two who had received antigen positive blood remained antigen negative, but one developed hepatitis B antibody (HB Ab).

Two other patients were also transfused with plasma.

Five had serological evidence of cytomegalovirus (CMV) infection accompanying the enzyme changes.

One patient who had received HB Ag positive blood remained antigen-negative and showed no abnormalities.

Five patients who became HB Ag positive, although they had been given antigen-negative blood, remained clinically and biochemically well.

Cytomegalovirus primary infection or reactivation occurred in another 32 patients; five had isolated, transient enzyme rises, one other was associated with a drug-induced focal liver necrosis and 26 showed no enzyme changes. Epstein–Barr virus infections, one of which was associated with a transient upset of enzyme activity, were detected in five patients. There were no cases of post-perfusion syndrome.

The co-ordinates of the dwellings where cases of variola minor (alastrim) occurred during a small epidemic were used in a worked example of contour mapping of disease spread. The contoured variable was the date of onset, relative to an arbitrary base date, of the case introducing the disease into each of twenty-two households. Three contour maps prepared with slightly different computer programmes or dates exhibited similar concentric loops whose centres were close to the first infected household. The average rate of spread of the disease was estimated by regression of the number of days to onset of the first case in the household on the average distance from an arbitrary origin to the relevant contour line. The calculated average rate of spread was 1.22 metres per day. An additional map was contoured using the cumulative number of cases as the contoured variable, relative to the onset of the example epidemic.

A combination of calciferol (vitamin D2) and warfarin, each at 0·025% in medium oatmeal bait, failed to control six of seven house-mouse (Mus musculus L.) populations infesting urban and farm buildings. In three further treatments with both calciferol and warfarin at 0·05 % in dehusked canary seed bait plus 5% corn oil, mortality, estimated from the consumption of pre- and post-treatment census bait, ranged between 94·2 and 97·4%. Finally, among sixteen treatments done with calciferol at 0·1% and warfarin at 0·025% in various cereal baits, the best results (97·0–100%) were obtained in six treatments where the bait-base was whole canary seed; this was so whether the poison bait was applied directly or after a 3-day pre-baiting period. It is concluded that calciferol at 0·1 % plus warfarin at 0·025 % is an effective combination against house-mice, especially when used with whole canary seed. The role played by warfarin in the poison mixture needs to be investigated further.

Since the earliest days of disinfectant testing bacteriostatic effect has misled many workers in this field. This problem has long been appreciated by some and a considerable battery of neutralizers has been employed, often with great success. Other anti-bacteriostatic measures, used without control, fail to revive damaged though viable organisms.

This paper sets out to describe some of the problems that are encountered in this confused field and the means whereby they may be overcome.

Methods of statistical analysis are presented for one or more dilution series experiments where the quantity of interest is the number of virus particles required to infect a cell. These methods are illustrated on several data sets drawn from the literature. Data from seven series, which have been used to support a two-particle model in the literature, are here shown to reject such a model decisively, whereas fifteen other experiments are found to be in excellent agreement with a one-particle model.

In both mice and one patient, a similar correlation was found between the oral dose of a ‘nonabsorbable’;aminoglycoside antibiotic selected for antibiotic decontamination of the digestive tract and the resultant faecal concentration. In mice, absorption of the orally-given antibiotics could only be demonstrated in animals treated with extremely high doses of 1440 mg. per kg. body weight per day. Evidence of absorption of gentamycin was found to occur in a patient after doses as low as 70 mg. per kg. per day.

The effectiveness of calciferol (vitamin D2) against Rattus norvegicus was investigated in field trials on twenty-three farms with rat infestations partly resistant to warfarin. At 0·01% combined with warfarin at 0·025% no rodenticidal effect of the calciferol was discernible. At 0·025% with warfarin at the same concentration, results were better, but not appreciably better than is often obtained with warfarin alone against resistant rat populations. When the concentration of calciferol was stepped up to 0·1%, four out of five treatments in which the poison was applied directly gave complete control. The fifth may have partly failed because of poison shyness caused by under-baiting. Five out of six more treatments done after ‘pre-baiting’ were also successful. The sixth failed for reasons unconnected with the choice of poison.

Six further infestations that were not responding adequately to warfarin treatments were quickly controlled when, in three instances, calciferol at 0·1% was used instead and, in three more, it was used together with warfarin. It is concluded that calciferol at 0·1% is an effective poison against R. norvegicus either combined with warfarin or not, but that because at 0·1% its effect is subacute rather than chronic, there may be a case in some environments for using it only after pre-baiting.

Seven smallpox vaccines of known human pathogenicity were tested for their ability to produce pocks on the chick chorioallantois at 39·7° C. Significant differences were found and the more pathogenic strains produced pocks with greater efficiency at 39·7° C. than did strains of average or low pathogenicity.

The effect of oral administration of neomycin cephalothin or kanamycin cephalothin on the aerobic intestinal bacterial flora, was studied in dogs maintained under isolation conditions in a conventional animal room. The dogs were successfully freed of aerobic bacteria with both combinations within two to seven days after the start of antibiotic treatment, and were maintained bacteria free for up to 21 days. Decontamination was attained more rapidly in dogs that were bathed in hexachlorophene surgical soap before and during the first and third days of antibiotic treatment. There was no evidence of toxicity from either of the antibiotic combinations. These results indicate that, as with mice and monkeys, decontamination of dogs with oral antibiotics is feasible. The technique is of potential value in preventing endogenous bacterial infections in canine experimental studies involving use of immunosuppressive agents.

The ability of Aureobasidium pullulans, Cladosporium herbarum and Cryptostroma corticale to produce local lesions in the rabbit was examined. Both C. corticale and A. pullulans can survive in vivo and produce the inflammatory response typical of mycetoma. C. herbarum failed to grow or survive in vivo.

The properties of 5-p-chlorophenyl silatrane as a rodenticide against Rattus norvegicus and Mus musculus were investigated in the laboratory. The high oral toxicity of the compound was confirmed. When the compound was given to laboratory rats and mice by stomach tube at lethal dosages, signs of poisoning were observed within a minute. When caged wild rats and mice were given a choice between plain and poisoned baits the optimum rodenticidal concentration in the bait was about 0.5% for both species, producing 50% mortality in wild rats and 95% mortality in wild mice. The results are discussed in relation to safety in use and the probable effectiveness of the compound as a rodenticide in field conditions.

During a period of five years 1192 water samples from swimming pools were examined for staphylococci and 338 for coliform organisms only. Eighty-nine different pools were sampled.

Numbers of staphylococci, estimated by the membrane filtration technique did not bear any significant relation to either bathing load or concentration of free chlorine.

Wide variation in the staphylococcal count was observed when different parts of a pool were sampled on the same occasion.

The only practicable standard for pool samples in relation to staphylococci would appear to be that these organisms should be absent from 100 ml. water when the pool has been out of use during at least ten hours before sampling if filtration and chlorination are adequate.

Between 1961 and 1972, 4547 independent strains of Staphylococcus aureus isolated from one hospital were examined for phage type. After 1967 there was a decline in the number of strains received, which we consider reflects a decline in the number of infections in the hospital, and which was largely accounted for by a great reduction in the number of strains in four ‘epidemic’ types. Overall, the number of multiple-resistant staphylococci received also declined; this was in part due to the decline in the epidemic types and in part to a reduction in the proportion of multiple-resistant strains of all types.

Studies on brucellosis were carried out to elucidate the epidemiology of the disease in Isfahan province, where Brucella melitensis is highly prevalent in animals and man. A positive milk ring test of 32% and 23% was found in unvaccinated goats and sheep respectively. Card and tube agglutination tests showed an infection rate of about 12% in sheep and goats and 42% in cattle. B. melitensis was isolated from 8% of 677 samples of fresh cheese examined.

Of 1526 clinically suspected human cases, 476 showed laboratory evidence of brucellosis. Of these patients, 291 cases were from urban and 185 cases from rural areas. Cases from urban and rural areas were seen principally in the younger age groups. The median age of infection was 19·7 in urban and 15·7 in rural patients respectively. The infection was encountered mainly from April to August. This correlates with animal parturition and the greatest amount of sheep and goat milk production, which is introduced to the local market as fresh cheese. Raw dairy product consumption is the most probable way of Brucella transmission in urban patients. In rural areas, both dairy product consumption and contact with animals are sources of infection.

Most babies are colonized by the predominant strains of Escherichia coli present in their own mother's faecal flora. Those babies who did not acquire their maternal faecal flora acquired strains of E. coli belonging to a small number of the possible serotypes. Moreover, the same serotypes were found in several babies and other mothers, suggesting spread within the ward. These few strains included some of the O groups which had previously commonly been found as urinary pathogens. These strains may have increased potentialities for colonization of human bowel. Antigenic and biochemical variation was observed among the strains.