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.

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 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.

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.

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.

An outbreak of foot-and-mouth disease in a partially immune population of cattle in Botswana is described. The results show that when cattle immunized by vaccination were presented with natural field challenge of FMD, many animals with immunity sufficient to protect them against clinical disease were, however, susceptible to pharyngeal infection and subsequently became virus carriers. The proportion of animals becoming carriers appeared to vary with the degree of severity of the challenge.

Vaccination before exposure to virus appeared to have little effect on the duration of the carrier state. No evidence was obtained of the spread of carrier virus to immune herds following the outbreak.

Antibody titres during the outbreak were higher in the clinically infected animals than in the carrier animals and the uninfected animals. Evidence suggested that natural challenge boosted the titres of immune animals. After the outbreak, however, it was not possible to distinguish by their antibody titres between the carrier animal and the virus-negative animal.

Antigenic studies on the strains of virus isolated are described.

The growth of eight strains of Newcastle disease virus in chick embryo chorioallantoic membranes was studied by comparing, at different times after infection, the amounts of haemagglutinin released into the allantoic fluid (extracellular haemagglutinin) with that associated with the membrane (cell-associated haemagglutinin). The virulence of the strains examined differed in that some killed chick embryos more rapidly than others. All strains released similar amounts of extracellular haemagglutinin and maximum titres were achieved about 12 hr. after infection. With virulent strains cell-associated haemagglutinin titres increased exponentially until the death of the host and maximum titres were much higher than those of extracellular haemagglutinin. With avirulent strains cell-associated haemagglutinin titres increased exponentially for only a limited time and titres were always lower than the titres of extracellular haemagglutinin.

Similar results were obtained when the titres of neuraminidase and viral ribonucleoprotein were measured during the growth of two virulent and two avirulent strains. Virulence appears to be associated with the continued intracellular accumulation of viral antigens.

A new serological method, the platelet aggregation (PA) test, was used to study Group B arbovirus infections, which are often associated with thrombocytopenia. The method is based on the interaction of antigen-antibody complexes with platelets. The PA test was nearly as good as the haemagglutination-inhibition (HI) test for epidemiological studies of tick-borne encephalitis (16 out of 18 HI positive sera) and was superior to the complement-fixation test which was positive in 10 out of 18 HI positive sera. The PA test could be used in the serological diagnosis of Group B arbovirus infection. The titres with the PA test were of the same magnitude as the HI titres, and about ten times higher than the CF titres. Two pairs of dengue haemorrhagic fever sera showed high initial PA titres. The role of immune complexes in the pathogenesis of haemorrhagic fevers is discussed.

Preparations of influenza virus A0 PR 8/34 and A 2 Malaysia/68 have been studied in the electron microscope. They were similar in appearance to preparations made by others. Each preparation was degraded by Triton N 101. The process of degradation appeared to be different from that observed using ether and, by inference, a number of other agents.

Highly purified influenza virus was degraded using anionic and non-ionic detergents. Best results were obtained using the non-ionic detergent Triton N101. Tests showed that virus extracts contained neuraminidase and a substance that reacted specifically with rabbit antibody to virus haemagglutinin (specific serum blocking substance). Haemagglutination-inhibiting antibody was produced when virus extracts were inoculated into guinea-pigs. Immunodiffusion tests showed that extracts were complex. Host-specific material was regularly found. Under appropriate conditions S-antigen was detected as a single line pattern component. Two or more virus-specific materials were also present. One of these was probably neuraminidase and the other the specific serum blocking substance.

An increase in the number of isolations of Mycobacterium xenopei from sputum suggested environmental contamination. The organism was recovered from water taps in 61 of 111 pairs of hot and cold water taps in one hospital, 20 of the 74 pairs in another hospital, but from only 3 of 61 pairs of taps in a third hospital and two of 34 pairs in private houses. Scotochromogens were recovered from taps in the first two hospitals only, and M. kansasii was isolated twice from the same tap in the first hospital. No mycobacteria were isolated from pigeon droppings or viscera, nor from patients' tooth brushes, tooth powder or razor debris. The source of contamination is not known.

The results of immunization of 523 children from 9 months to over 5 years of age with two attenuated measles vaccines, ‘Denken’ and ‘Biken’, are described. The clinical reactions following vaccination with both vaccines were mild, but Denken vaccine produced more rashes than the Biken vaccine. The serological conversion was satisfactory for both vaccines but a higher titre of neutralizing and haemagglutination-inhibiting antibodies was found in children immunized with Denken vaccine. The incidence of severe reactions or complications was negligible in this trial. The immunity to diphtheria or tetanus was not altered by vaccination with live measles vaccine.

Results from clinical isolations confirmed that mercury resistance is common among antibiotic-resistant strains of Staphylococcus aureus present in a large general hospital although the correlation is not as high as that found by Moore (1960).

The distribution of mercury-resistant strains among infections and carriers in surgical, medical, obstetric and geriatric patients and staff was studied. Attention was directed to the distribution among carriers since there are fewer extraneous factors operating among them, and a statistical analysis was made on the total number of mercury-resistant strains and the number of non-endemic strains; this latter figure was obtained by subtracting the dominant type 80/81, which is nearly always mercury-resistant and antibiotic-resistant, from the total. Analysis showed the geriatric patients to have a significantly higher proportion of mercury-resistant strains in both cases, and obstetric patients to have a significantly lower proportion when the total number of mercury-resistant strains was considered. Among the surgical, medical and staff categories, no significant difference in proportions could be found although a trend, in that order, of decreasing proportions of mercury-resistant strains present was noted.

In those cases infected on admission with tetracycline-resistant strains, although mercury-resistant strains still predominate, mercury-sensitive strains make a sizeable contribution. This is a reflexion of their dominance in the non-hospital environment.

Reasons for the accumulation of mercury-resistant strains of Staphylococcus aureus in hospital have been studied. A collection of paired strains, that is staphylococci similar in every respect except sensitivity to mercury salts, was made. Tests were made in an attempt to demonstrate a link between mercury resistance and some other factor which might aid survival, viz. resistance to drying and heat, production of bound coagulase, growth in the presence of sublethal amounts of tetracycline, survival in human blood at 37°C. and uptake by polymorphs at 30°0. and 37°C., development of resistance to antibiotics and competition in mixed cultures. It was not possible to demonstrate any consistent link between mercury resistance and any of these properties. Paper strips impregnated with the mercurial diuretic, Mersalyl, were shown to differentiate between mercury-resistant and -sensitive strains in vitro. Furthermore, development of resistance to mercury by passage in mercuric chloride-broth was demonstrated.

It is proposed that mercury resistance has developed as a result of exposure to the mercury ion. Mercurial diuretics have been frequently used in medical and geriatric patients and it is among these that the higher carrier rates of mercury-resistant strains are found even when the local endemic strain is disregarded. In obstetric patients, where mercurials are seldom used, mercury-resistant strains are rare.

Nasal carriage of factory workers exposed to mercury products showed that this group is likely to carry resistant or partially resistant strains.

The effect of various concentrations of sodium thioglycollate (0–0·05 %) on the recovery of spores of four strains of clostridia was investigated. The results showed that thioglycollate at a concentration of 0·01 % can be inhibitory to some clostridia. However, the results also indicated that the inhibitory effect is dependent upon the composition of the growth medium. The presence of glucose appeared to be particularly important in reducing the inhibitory effect. These findings support the view that the use of sodium thioglycollate in sterility test media should be discontinued.

The response of wild and domestic rabbits with a degree of genetic resistance to myxomatosis has been shown to be markedly affected by the age at which they were infected with a virulent strain of the virus. The response, in terms of mean survival time and percentage survival, fell with increasing age from 10 to 30 weeks with little change thereafter.

The isoquinoline compound UK 2054 prevents the uptake of influenza virus by susceptible cells. Pre-incubation of virus particles with 500μg./ml. UK 2054 at 37°C. for 2 hr. does not reduce virus infectivity. Host cells vary in their responsiveness to the inhibitory effect of UK 2054; virus multiplication is inhibited in chick allantoic cells by lower concentrations than those required to inhibit virus growth in chick embryo fibroblasts. The effectiveness of UK 2054 is reduced by the presence of serum.

It is concluded that inhibition of influenza virus multiplication by UK2054 might result from interaction of the inhibitor with both virus and cells. Any direct combination between inhibitor and virus is completely reversible.