The susceptibility of the tissue culture system to small amounts of residual live virus was not influenced by the inactivated antigen present. The depth of inoculum over the cell sheet did not affect results. Negative cultures frequently gave positive first (but not second or later) sub-cultures.

Baby hamster kidney cells were always more sensitive than cattle tongues to infection with any of the strains used.

Confidence in the safety test depends on the number of vaccination doses used; the tissue culture test can be made much more reliable than the cattle test because it is not limited to the 15 ml. of inoculum that restricts the cattle test.

The bactericidal activity of Tego 103S was compared with that of chlorhexidine in ethanol, and Tego 103G with Halamid. The activity was determined on Pseudomonas aeruginosa, Staphylococcus aureus and Achromobacter anitratus by various methods. Tego 103S in 1% solution was less active than chlorhexidine 0·5% in 70% ethanol, and Tego 103 G in 1% solution was less active than Halamid 0·3 %. The presence of serum did not noticeably influence the activity of the Tego preparations.

On 14 November 1967 an investigation was begun at the University of South Florida to determine the cause of an increased number of gastrointestinal illnesses on campus. An estimated 300 students suddenly became ill with nausea, vomiting, abdominal pain, and diarrhoea. While at first food poisoning was suspected, no common food, water, or toxic exposure could be found. The data collected were most consistent with Winter Vomiting Disease. This entity is characterized by acute gastrointestinal illnesses which may occur in epidemic form in residential schools between September and March. Most investigators suspect that a viral agent is responsible for the illnesses, though attempts to isolate a virus have been unsuccessful. The incubation period in the University outbreak was estimated at 28 hr., and contact was the most likely mode of transmission. The outbreak illustrated that Winter Vomiting Disease in residential institutions may be an accentuation of the gastrointestinal illnesses occurring simultaneously in the community at large.

Natural aerosols of rabbit pox virus produced by groups of infected rabbits were sampled with a slit and Andersen sampler using an adhesive surface sampling technique (Thomas, 1970). The higher rate of successful recoveries of airborne virus compared with a previous report is believed to be due to the much larger volume of air sampled by this technique and to the processing of the whole of the sample collected by the direct addition of a cell suspension to demonstrate the presence of viable virus.

The serological responses of cattle to inoculation with Brucella abortus and Yersinia enterocolitica type IX were compared. Complete cross-reactions were found in serum agglutination, antiglobulin, complement fixation and Rose Bengal plate tests. The cross-reaction between Br. abortus and Y. enterocolitica IX was confirmed by immunodiffusion tests. Although antibodies specific for each organism could also be detected by immunodiffusion tests with high titre rabbit or bovine sera, these tests were insufficiently sensitive for routine diagnostic use.

A quantitative Rose Bengal plate test, using Rose Bengal stained Br. abortus and Y. enterocolitica IX, was developed which enabled the antibody responses to the two organisms to be differentiated. The specificity of this test was confirmed by cross-absorption experiments and its sensitivity was sufficient to permit evaluation of all bovine sera giving positive reactions to the serum agglutination test.

By using neutralization, complement fixation and immunogel-diffusion tests, it has been demonstrated that cross-reactions occur between various avian pox viruses and between sheep pox and goat pox viruses. No such reactions were demonstrated between avian pox viruses and vaccinia virus or between avian pox and sheep pox and goat pox viruses. Furthermore, no serological relationship was demonstrable between vaccinia virus and sheep pox and goat pox viruses.

Antistreptolysin O titres in the sera of children in a rural population of Ceylon were determined, to establish the upper limit of the normal ASO titres in nonrheumatic children, and to compare these ASO titres with results of surveys done in other countries.

Swabs were taken from throats and ulcers of the children examined and cultured specifically for group A haemolytic streptoccoci. Of a total of 257 children, 29·5 % had ASO titres of over 166 Todd units. The greatest number of children showed ASO values between 100 and 166 units. The percentage of children showing values over 166 units increased with age until a maximum of 54 % was reached between 9 and 10 years. Group A haemolytic streptococci were isolated from five throat swabs, but there were no isolations from ulcers. The values obtained from this survey have been compared with those from a few other developing countries.

The relationship between the serological findings for brucellosis and the epidemiological factors has been studied in veterinary surgeons in Northern Ireland. The anti-human globulin (Coombs) test and the complement-fixation test for brucella were used in two groups of veterinary surgeons, those self-employed and those employed by the Ministry of Agriculture.

Significant serological differences were found to exist between the two groups. Those in private practice showed changes related to age, cattle skin rash, reactions to S. 19 vaccine accidents and symptoms suggestive of brucellosis in the past or the last year. But those working for the Ministry only showed titre changes related to the length of their private practice experience before joining the Ministry. In neither group was there a relationship between serological findings and the type of milk drunk or any particular group of symptoms suggestive of brucellosis.

The findings indicate that high titres to brucella by the Coombs and complement-fixation test can occur in people repeatedly exposed to infection at work. Titres which would be of diagnostic importance in the rest of the population may be of little diagnostic significance even when they are as high as 160 Coombs and 128 complement fixation.

The primary body site of acquisition of group A streptococci was examined prospectively in a population with endemic streptococcal pyoderma. Weekly cultures were obtained during the skin infection season from apparently normal upper respiratory and cutaneous sites (and from skin lesions when present) in 44 children and adults living on the Red Lake Indian Reservation.

During the 9-week period of the study 705 of a total of 2305 cultures were positive for group A streptococci. The percentage of positive cultures from the various sites were: throat (20%); nose (24%); wrist (32%); ankle (35%); back (22%); and skin lesions (81%). Group A streptococci were also isolated from fingernail dirt, clothing and bedding as well as from a few household pets and insects.

Analysis of serial cultures obtained from the same individuals at weekly intervals suggested that the strains isolated from skin lesions first appeared on normal skin in the 2 weeks preceding the lesion. Spread to the nose and throat followed skin acquisition and/or skin lesions.

The high prevalence of group A streptococci on normal skin in the absence as well as the presence of pyoderma, and their appearance on normal skin before recovery from either skin lesions or the upper respiratory tract are consistent with the view that skin acquisition was a primary predisposing factor to pyoderma. Since the literature indicates that group A streptococci are rarely part of the normal skin flora, these findings raise the possibility of unique biological properties of these and perhaps other pyoderma strains, as distinct from other group A streptococci.

A survey was carried out on the occurrence of Vibrio parahaemolyticus on fish and shellfish, as sold in The Netherlands.

The optimal mode of detection of this bacterium appeared to be: (i) enrichment of swabs taken from the surface and the gills in freshly prepared meat broth with 5% NaCl; (ii) streaking onto Teepol bromothymol blue agar (BTB) and taurocholate bromothymol blue sucrose agar (TCBS); (iii) confirmation of suspect colonies by testing for mode of growth in butts/slants of a Kligler type glucose sucrose iron thiosulphate agar, formation of indole in 2% NaCl 2% trypticase water, anaerobic utilization of starch in the presence of 5% NaCl and oxidase reaction according to Kovacs (1956).

A total of 407 samples, stemming from 17 types of fish and shellfish, taken at three fish shops, was examined by this technique. Only one specimen, i.e. a haddock, was found to contain V. parahaemolyticus. This contamination rate of approximately 0·3% correlates well with data found earlier for fish landed in Northern Germany.

The spread of Staphylococcus aureus was studied in three general surgical wards of identical design which consisted of a number of separate rooms, and the results were compared with those in the same unit previously studied, in subdivided wards elsewhere and in large open wards.

The nasal carrier rate of Staph. aureus by patients rose during their stay in the ward, but its peak rate was comparable with minimum rates reported in other subdivided wards and was lower than in open wards.

Staphylococcal sepsis rates were lower than in most open wards and were also much lower than those found previously in the same unit when overcrowding was common and each sex had its own ward.

Studies of the effect of Hong Kong (HK) influenza vaccine were made in adults and children in Great Britain during 1968 and 1969. The vaccines were administered intramuscularly and also by intranasal spray. The serum antibody response was studied in 284 subjects. Most developed rising titres to vaccine given intramuscularly and few to vaccine given intranasally. Deoxycholate-split vaccine was as potent as conventional whole virus vaccine. Antibody titres were maintained for months. Over 4000 subjects in factories, offices and schools were observed during the epidemic. The incidence of disease was not significantly reduced by either form of vaccination. A survey was made of epidemics in boarding schools in which some of the pupils had been vaccinated, in six with commercial polyvalent vaccine and in five with HK; there was a lower incidence of influenza in two schools vaccinated 2 or 4 weeks earlier with HK vaccine.

When ten cats were infected orally with undiluted or a 10−1 dilution of virulent feline infectious enteritis (panleucopaenia) virus, all developed severe leucopaenia followed by the development of demonstrable antibody, but none died. Eighteen of 29 cats given a 10−2 dilution of virus died of the disease. Three of the survivors had white blood cell counts of less than 4000 and three had counts between 4000 and 6000 cells. Although the remaining five animals never had individual counts of less than 6000 cells, the geometric means of these counts showed that a marked depression in the leucocyte counts had occurred. All surviving cats developed antibody.

Among the ten cats dosed with either 10−3 or 10−4 dilution of virus, four died of feline infectious enteritis and three developed antibody after falls in the leucocyte counts. It is suspected that low dilutions of feline infectious enteritis virulent virus in cats produce a phenomenon similar to that reported by von Magnus (1954) with influenza virus in eggs.

Leucopaenia is commonly defined as less than 4000 white blood cells/mm.3 of blood. Counts lower than this are usual in cats which either die of the disease or have received large doses of virus; they are less common in cats surviving after administration of diluted virus. Challenge of cats with pre-existing antibody did not provoke a depression in the leucocyte counts.

Unpurified and purified smallpox vaccines were prepared from calf dermal pulp, or chorioallantoic membrane (CAM) of hen eggs infected with vaccinia virus, and freeze-dried. The protective effect of various suspending media was investigated both in the course of the freeze-drying and in the period of subsequent storage of the dried product at different temperatures, including 100° C.

Single media consisting of either sodium glutamate or peptone were effective in the preservation of both unpurified and purified vaccines prepared from calf dermal pulp or CAM. It was shown that there was an optimal concentration of sodium glutamate for the preservation of the vaccine preparations, especially of the purified vaccine.

Combined media, consisting of soluble starch, polyvinylpyrrolidone or sodium carboxymethyl cellulose with sodium glutamate, were effective with the purified vaccine when the concentration of sodium glutamate exceeded the optimum necessary for preservation.

A total of 1601 adult industrial workers were vaccinated with either monovalent inactivated vaccine of the Hong Kong strain of influenza A virus, or with polyvalent vaccine containing only pre-1968 Asian viruses. Serological investigations on a random sample of volunteers showed that 53/56 (95 %) given Hong Kong vaccine developed a significant rise in specific haemagglutination-inhibiting antibody; final titres were 1/48 or greater in 39 (70%) and the GMT (geometric mean titre) was 96·5. After polyvalent Asian vaccine, 40/67 (60%) also produced antibody against Hong Kong virus, but only 21 (31 %) had final titres of 1/48 or above, and the GMT rose only to 14·1. An intranasal spray of the Hong Kong vaccine in addition to injected Asian vaccine gave no additional increase in antibody.

Each type of vaccine stimulated a recall of pre-existing antibody against Asian viruses. The possible significance of heterologous responses to the two vaccines is discussed.

The incidence of clinical influenza in the trial population was sporadic, and the infection rates were too low to allow any accurate estimate of the protective efficiency of the two vaccines.

Vaccines were prepared from a single pool of high-titred vaccinia virus and inactivated by six methods, namely heat, formalin, hydroxylamine, β-propiolactone, ultraviolet irradiation, and visible light and methylene blue. Large doses of the vaccines were required to protect mice against intracerebral challenge. Differences in protection were not attributable to the method of their inactivation. The vaccines also induced similar degrees of skin immunity in rabbits which showed no severe dermal reactions when challenged with either homologous killed vaccine or live virus. The virus-neutralizing, haemagglutinin-inhibiting and complement fixing antibody responses to the vaccines differed; heat-inactivation preserved these antigens least well and β-propiolactone apparently the best. In both rabbits and mice there was little association between the different antibody responses to each vaccine or between the degrees of antibody response and the protection they induced. The relation of these findings to pox-virus immunity and the use of inactivated smallpox vaccine in man is discussed.

The direct complement fixation test was performed to follow the antibody response in chickens infected with avian infectious bronchitis virus. Concentrated allantoic fluid (4 units) was used as an antigen and allowed to react with serially diluted antiserum in the presence of two complete units of guinea-pig complement for 3 hr. at 4°C. and ½ hr. at 37°C. before the addition of sensitized cells. Serum was unheated and used either fresh or within one month of storage at −30°C. Individual birds showed a rise and fall of complement-fixing antibody both after primary and secondary inoculations. The complement-fixing antibody was detected as early as the seventh day after primary inoculation. The highest complement fixation titre (1/32 to 1/64) was recorded from 14 to 21 days after inoculation with a subsequent gradual decline.

The results of the direct complement fixation tests have been correlated with the serum neutralization test. The neutralizing antibodies usually appeared by the 14th day but were not detected at a significant titre until the 21st day after primary inoculation. Serum neutralizing antibodies were still present at high titres even after 7 weeks of infection but the complement-fixing antibodies had disappeared by that time.

An investigation of staphylococcal epidemiology was undertaken at an Australian National Antarctic Research Expedition station during 1965–1966. It concerned the carriage of staphylococci by the men and their dogs, and the occurrence of staphylococci in the station environment. The year-long study indicated that coagulase-negative strains survived better in the Antarctic environment than coagulase-positive strains. It was demonstrated that naturally acquired coagulase-positive strains could not maintain colonization on forearm skin under the usual cold exposure experienced at Mawson station, though coagulase-negative skin strains appeared to thrive during the winter. Staphylococcus albus and S. aureus were able to persist in the anterior nares, despite the sometimes lower temperatures recorded in this micro-climate, probably because of the greater humidity and denser populations found there. The majority of the nasal carriers of S. aureus were persistent carriers, only two men in 27 being found to be occasional carriers of nasal strains, which was consistent with the observation that transfer of this pathogen from man to man is not common under Antarctic conditions. Half of the 27 sledge dogs at the station were found to carry coagulase-positive staphylococci but this did not appear to be of pathological significance to their human handlers. The local inanimate environment, including mess hut, sleeping huts and sleeping bags used on expeditions, was searched for contamination by S. aureus but none was detected.

This is a survey of 10 years experience in trying to find out how to control hospital sepsis economically. We appear to have obtained reasonable improvements in hygiene by applying the teaching which has been given to students since the time of Leonard Colebrook. For our investigations we used only routine methods.

The order of importance of the factors in reducing cross-infection would appear to be: (1) single rooms for all septic cases and for those requiring protective isolation; (2) a sister supported in complete authority over anyone entering the unit; (3) a simple, inflexible drill to introduce an impermeable layer between the nurse or doctor and the patient—gloves and apron provide this; (4) overshoes and barrier mats; (5) hygienic disposal of linen; (6) an efficient wet dusting and floor cleaning system. Anything beyond this must be justified by saving of nursing time or some factor other than prevention of infection.

Calf thyroid tissue cultures were found to be the most sensitive system in detecting virus collected in a large volume air sampler from boxes, where cattle, sheep and pigs infected with A and C strains of foot-and-mouth disease (FMD) virus were housed. It was confirmed with all strains of FMD virus tested that pigs excreted the most virus followed by cattle and sheep, but there was variation between strains, the highest virus recoveries being obtained from animals infected with O1 and C Noville viruses. The results are discussed in relation to outbreaks of foot-and-mouth disease in Great Britain since 1954.