The outbreak of typhoid fever in Aberdeen during 1964 (Walker, 1965) presented an opportunity to study the antibody titres of typhoid fever patients and of TAB immunized individuals to obtain further knowledge concerning the behaviour of these titres with the passage of time.

This paper gives an abbreviated version of part of a research programme which followed the Aberdeen typhoid outbreak of 1964.

The antibody titres of patients were followed up for a period of 2 years after discharge from hospital and the findings have been compared with those in TAB immunized healthy individuals. The following points emerged:

(1) The value of the Widal test as an aid to diagnosis was limited;

(2) the flagellar antibody titre in patients' sera provided a more reliable aid towards diagnosis than did the somatic antibody titre;

(3) the response of immunized and non-immunized patients to the somatic antigens was poor and often delayed well into the period following discharge from hospital;

(4) titres of 1/40 and over for Vi agglutinins were present in immunized and non-immunized patients for at least 12 months after discharge without their being S. typhi excretors;

(5) Vi agglutinin titres as high as 1/40 were present in TAB immunized healthy individuals and also in members of the general public;

(6) the presence of S. typhi septicaemia need not result in a high antibody titre; (7) patients who relapse, may do so without enhancement of previous antibody titres and may relapse even in the presence of earlier appreciable titres.

In a previous paper (Brodie, 1977) the value of the Widal test in the diagnosis of typhoid fever was shown to be limited. Evaluation of possible alternative tests showed that:

(1) the sensitivity of the anti-human globulin (Coombs') test appeared greater than that of the agglutination test but the length of time (48 h) before results were available rendered it of little value in rapid diagnosis;

(2) the complement fixation test offered no particular help towards diagnosis;

(3) immunized and non-immunized typhoid fever patients developed fimbrial antibodies, as also did immunized healthy individuals. In this latter group, however, those immunized with alcoholized TAB vaccine had higher antibody titres to fimbrial antigen than those immunized with heat-killed phenolized vaccine.

Clothes-borne transmission is an important way of spread of infection from patient to patient which is not interrupted by common cotton gowns. New barrier garments were designed from spun-bonded olefin that, in particle penetration tests, was 100 times better as a filter than cotton cloth. Three designs, a gown, a loose coverall and a close coverall, were compared with each other and with conventional cotton gowns in experimental exercise and nursing procedures. Staphylococcus aureus from burned patients were used as markers. The close coverall was 4–7 times better than the loose coverall or gown in preventing the soiling of clothes worn underneath it, but appeared to permit substantially more transfer from garments underneath it to a mock ‘patient’ and to the air than did the looser garments. A cotton gown reduced the soiling of clothes underneath it by more than 10 times and the contamination of a mock patient by more than 30 times as compared with no barrier garment. The close coverall further diminished the contamination of clothes but not the transfer to the patient. The possible mechanisms for the discrepancy between particle transmission tests and experimental procedures are discussed.

Ferrets immunized with an H3N2 recombinant of A/PR/8/34 and A/Scotland/ 840f74 (RIT 4025 vaccine strain) were almost completely protected against a challenge with the homologous strain A/Scotland/ 840/ 74. The protection was lower but highly significant when the challenge was performed with the heterologous A/Victoria/3f75 wild strain. The protection afforded by the vaccine strain was measured by three indicators: absence of temperature rise, absence or reduction of virus shedding and absence or reduction of nasal protein increase when compared with uninoculated controls.

Heterotypic immunity in this animal model was not significant when these three indicators were measured after a challenge inoculation performed 5 weeks after immunization.

Myxomatosis on the Western Plains is an enzootic disease in contrast with the epizootic pattern which is general in eastern Australia. The most unusual aspects are the presence of significant numbers of diseased rabbits throughout the winter and the continuously low percentage of rabbits with antibodies to myxoma virus.

Climatic and topographic conditions are unsuited to the production of the high densities of mosquitoes necessary for widespread epizootics. Under these conditions the effects of less efficient methods of myxomatosis transmission are apparent. The unusual epidemiology of myxomatosis has resulted in selection for virulence of the virus similar to that which has occurred under summer epizootic conditions. All field strains are now in the mid range of virulence.

An epidemic of acute haemorrhagic conjunctivitis (AHC) recurred at Lucknow during July to September 1975, after a gap of 4 years. Out of the 35 cases investigated thoroughly, 20 Entero-70-like cytopathogenic agents were isolated from the conjunctiva which were neutralized by antisera against AHC virus J670/71 of Japan. Seroconversion was seen in 7 out of 11 paired sera from patients. Serological study was also done on 100 sera after 1975 epidemic. There were no neutralizing antibodies in the pre-epidemic period, while 18% of sera after the first epidemic and 32% after the second epidemic showed antibodies. The incidence of antibodies was highest (43%) in children aged below 10 years. Of the children born after the first epidemic, 44% had antibodies. Thus our findings show that the AHC virus appeared for the first time at Lucknow in 1971 and the almost complete absence of disease in children, and its mildness during second epidemic, may be due to immunity.

In an effort to provide guidelines for standardizing aeration times for plastics sterilized with ethylene oxide, an Aeration Index has been developed. Based on the rate of diffusion of ethylene oxide in selected polymers, the Index provides an indication of the aeration time at ambient temperature (23°C) for the ethylene oxide concentration in freshly sterilized plastics to drop to 50 parts/106.

Using direct agglutination methods, a simple serological scheme for the classification of Bacteroides fragilis is described. Twenty strains of B. fragilis were selected by a process of successive screening from 151 strains obtained from various sources. O-antigens were prepared from the 20 strains, and used to raise antisera in rabbits.

Each of the 20 antisera reacted with its homologous antigen and eight antisera cross-reacted with other subspecies. These cross-reactions were successfully removed after absorption of the antisera with the cross-reacting antigens, resulting in 19 type-specific antisera, titres ranging from 40 to 320, and 19 distinct serotypes of B. fragilis. There was no correlation between the antigenic and the biochemical characteristics of these strains and no cross-reactions occurred with other gram-negative anaerobes, B. melaninogenicus, Sphaerophorus necrophorus and Fuso-bacterium necrogenes.

Forty-four haemagglutinating viruses were isolated from the pooled tracheal/cloacal swabs of the dead birds from 170 consignments of caged birds arriving at Heathrow Airport over a period of 6 months. Two isolates were identified as Newcastle disease virus but the remaining 42 were all identified as influenza viruses with Hav 7 Neq 2 antigens. All the consignments from which influenza viruses were isolated originated in India but had widespread destinations. The NDV isolates were from birds originating in central America and destined for Japan.

The effect of a sublethal dose (0·5 LD 50) of influenza A/WSN (H0N1) administered intranasally in the 1st and 3rd weeks of pregnancy was studied in C3H inbred mice. Maternal and neonatal mortality rates were significantly increased by infections in the 3rd week of pregnancy, but not in the 1st week. Infections during the last part of the 1st week significantly depressed the growth rate of neonates. No evidence of viraemia, transplacental transmission or congenital malformations were observed from infections during either week. The results are discussed in terms of a possible model for human influenza infections during pregnancy to determine the potential risks to the mother, fetus and neonate.

The transfer of an R factor from donor E. coli introduced into the rumen of adult sheep to strains of the coliform microflora resident post rumen in the lower gastro-intestinal tract was found to be greatly increased when the animals were subjected to a short period of starvation (ca. 24–48 h). This also resulted in coliform organisms containing the resistance determinants of the R factor being excreted for much longer periods, sometimes for months afterwards. As no antibiotic treatment was given to the animals during these experiments, possession of the R factor should have conferred no selective advantages on the host cells and other plasmids could possibly be transferred similarly in vivo in sheep or other ruminants and perhaps also within the gut of monogastric animals.

In the Cambridge area, 143 patients infected with Corynebacterium haemolyticum were found during the period May 1967 to December 1974. The pharynx was the commonest site of infection and 100 of the 137 pharyngeal infections were in patients aged between 15 and 25 years. Such patients usually had a sore throat; about half of them also had a maculopapular rash. The organism and the clinical features which we have come to regard as typical of this infection are briefly described.

The resistance of Salmonella dublin to eight antibacterial drugs was assessed wider diagnostic laboratory conditions. Two techniques were used consecutively and the differences in the results are described. Strains of S. dublin isolated from either calves, adult cattle or abortion material showed no differences in resistance for either of the techniques, though differences between the two techniques were found.

Analyses of outbreaks of African horse sickness showed that movement of infected Culicoides midges on the wind was most likely responsible for the spread of the disease over the sea from Morocco to Spain in 1966, from Turkey to Cyprus in 1960, and from Senegal to the Cape Verde Islands in 1943. The pattern of spread of the epidemic in the Middle East in 1960 could have been laid down by the infected midges carried on spells of south-east winds, and analyses of outbreaks in Algeria in 1965 and India in 1960 also suggested windborne spread of the disease. Each spread occurred when the presence of virus, host and vector coincided either with a spell of winds unusual for a particular time of year (Spain, Cyprus, Cape Verde Islands and Algeria) or with a series of disturbances usual at that time of the year (Middle East and India). Inferred flight endurance of the midge varied up to at least 20 h and flight range from 40 to 700 km. Flight occurred when temperatures were likely to have been in the range of 15–25 °C if it was at night or 20 to about 40 °C if it was by day.

It is suggested that likely movements of midges on the wind can be estimated from synoptic weather charts, and should be taken into account when planning control of the disease in the face of an outbreak. Such control includes a ban on movement of horses, vaccination and spraying of insecticide.

The risk of spread to countries outside the endemic areas should be assessed by reference to possible wind dispersal of infected midges.

Cross-sectional surveys of infection in relation to ward structure and practice were made in 38 hospitals between 1967 and 1973, including repeat surveys in 12 hospitals. The survey team (a research nurse and a senior microbiologist or technician) visited one ward a day and entered data on patients, including appearance of wounds seen at change of dressings, on the structure of the ward, and on ward practices; bacteriological swabs were taken from noses of all patients and staff of wards visited and from infected or open wounds, also from some environmental sites. Effect of age, sex, length of hospital stay and antibiotic use on carriage of tetracycline-resistant Staphylococcus aureus and on post-operative sepsis are considered here.

Clinical infection (sepsis), further classified as ‘severe’, ‘moderate’ or ‘mild’ in accordance with a code of physical signs, including inflammation and suppuration, was found in 6·1% of clean undrained operation wounds. Drained wounds and those through hollow, heavily colonized viscera (‘contaminated’ wounds) had higher sepsis rates than undrained and ‘clean’ wounds; there was less sepsis with closed drainage and with small drains. Staph. aureus (24%) was the commonest single bacterial species, but gram-negative bacilli (50%) were found in a much larger proportion of septic wounds. The results showed that the infection rate was lowest among patients between 20 and 40 years old. Infection was significantly more common in male than in female patients.

Nasal carriage of tetracycline-resistant Staph. aureus, used as an index of hospital-acquired infection, was commonest in geriatric patients and least common in gynaecological patients. There was correlation between nasal carriage of tetracycline-resistant staphylococci and age of the patient, length of hospital stay, sex, (male greater than female), operative treatment, and treatment with tetracycline, ampicillin and nitrofurantoin, but not with penicillin.