The single radial haemolysis test is conveniently practical and economical and promises to have wide applicability in the study of influenza antibodies in human populations. It can also be adapted for preliminary examination of new virus isolates during epidemics.

Using this test a rather higher proportion of the population in the Highland Region of Scotland was found to possess antibody to a recent epidemic strain of influenza (A/Scotland/74) than was the case in the south of England. Antibody was detected and apparently evenly spread throughout all but the most remote island communities. Some evidence of the spread of the subsequent variant, A/Victoria/75, was obtained. Most of the school children in our study had high antibody titres to recent strains but the proportion with high antibody titres to these strains declined speedily from the age of 17 years onwards.

Haemagglutination inhibition (HI) antibodies against the influenza viruses A/Hong Kong/8/68 (H3N2) and B/Nederland/77/66 were determined in 420 paired sera from mothers and newborns (umbilical cord sera), sampled in 1970–1.

A higher concentration of antibodies against influenza A virus was found more frequently in neonatal than in maternal sera. By contrast, low titres against influenza B virus were more frequently observed in neonatal than in maternal sera. Maternal age, duration of pregnancy, and birth-weight did not affect the results of the tests.

It is suggested that the titre of the newborn against an epidemic influenza virus can be predicted from that of the mother. Furthermore, the maternal titre may be an indication of the susceptibility of the newborn infant to influenza infections.

The effect of blood group status on the incidence of epidemic influenza A (H3N2) infections and on serological response to influenza vaccination with killed subunit and live attenuated vaccines have been investigated during comparative vaccine trials in Western Australia. A significantly higher incidence of epidemic influenza was observed in subjects of blood group B compared with those of other blood groups, regardless of whether they had serological evidence of previous exposure to H3N2 antigens or not. Volunteers of different blood groups exhibited similar seroconversion frequencies to both vaccines after the administration of two doses, but a significantly higher proportion of blood group A subjects seroconverted after receiving their first dose of live attenuated vaccine compared with those of other blood groups. Although this finding was inconsistent with the increased incidence of epidemic influenza in subjects of blood group B, it is discussed in terms of the methods employed to obtain attenuation. Higher geometric mean HI antibody titres were observed in blood group O subjects after the administration of killed subunit vaccine. The results described in this report supported the contention that genetic factors linked to ABO blood groups may play a role in susceptibility to infection with influenza A virus, but that any association must be indirect.

Two-dimensional quantal microneutralization tests on foot-and-mouth disease viruses, in which neutralizing antibody activity was titrated against a serial range of virus doses, demonstrated a variety of dose-response curves some of which were rectilinear, others clearly curvilinear. Moreover, in the case of the non-linear responses obtained with some antisera, the shape of the curve was such that antibody titres recorded with doses of virus ranging from 103–105 TCD 50 were closely similar. Studies were carried out on the effect of varying the conditions of the test on the shape of the dose-response curve: significant differences were obtained after treatment of the antiserum–virus mixtures with anti-species globulin, and when the test was assayed in cells of differing susceptibility to infection.

The fluorescent antibody technique was used to investigate an epidemic of Klebsiella infection in a urological ward and to trace the probable source to a contaminated sink in the treatment room. It was also shown that cross infections by particular capsular types were very common within each ward. Certain types of Klebsiella occurred in cut-flower water but could not be associated with the types infecting the patients.

Antibiotic resistance patterns within one capsular type were found to vary whether the type was from different sources in one patient or from different patients in the same ward. One capsular type was observed to develop resistance to increasing numbers of antibiotics over a 3-year period. This was probably due to the acquisition of R-plasmids. There also appeared to be a relation between capsular type and the site of infection.

The frequency of Klebsiella infections in the urological wards dropped significantly after up-grading the treatment room, improving catheter storage and reducing ampicillin use.

In this investigation the bacterial contamination of surfaces such as walls and floors in a modern operating suite, together with surfaces of lamps in the operating theatres, and the clogs worn by staff, was studied. Counts of colony-forming units were made on impression plates containing blood-agar with Tween 80 for total bacterial counts, Baird Parker medium with egg yolk and tellurite for Staphylococcus aureus and trypticase peptone agar with neomycin and polymyxin for Clostridium spp.

The areas examined were divided into the patients' route to the operating theatre, the staff's route, and the central area containing the operating rooms, anaesthetic rooms, and exit and scrub-up areas. In the patients' route counts of total organisms ranged from about 10 000 to 30 000/m2 for Staph. aureus the range was from 70 to 540/m2. In the staff's route the highest count was about 70000/m2 in the dressing area, and the numbers of Staph. aureus were about the same as along the patients' route. In the inner zone the counts were somewhat lower for both total organisms and Staph. aureus. Total counts on the floor from all areas of the inner zone were significantly higher just before the second operation than before the first operation on the same day. The total and Staph. aureus counts on walls, floors and lamps were the same after clean operations as after operations classified as ‘contaminated’ or ‘dirty’.

Mice from Loughborough and Nottingham were obtained in order to compare the inheritance of warfarin resistance in these populations with that established for a Cambridge population (Wallace & MacSwiney, 1976). Using the same breeding programme and warfarin testing technique, it is established that resistance in the new areas is, as in the Cambridge area, controlled by the major resistance gene, War, in chromosome 7, with penetrance affected by sex and modifiers. In addition, survival differences in males of different ages strongly suggests that War + has less penetrance with age. Penetrance differences between the experiments establishes that wild populations differ in their modifier complex and that more than one modifier, probably several, exist. Questions are posed as to the adaptive significance of the phenomena, and the way in which they work, in the patchwork of warfarin baited and unbaited areas in this country.

Baiting with medium oatmeal or soaked wheat containing 0.002, 0.001 or 0.0005% brodifacoum completely controlled infestations of warfarin-resistant rats on farms when the poisoned baits were maintained until rats ceased to feed on them. The concentration of brodifacoum did not affect the duration of these treatments which lasted from 11 to 25 days.

Poison baiting with 0.002% brodifacoum for only 1, 4 and 7 days achieved, respectively, only about 41, 51 and 68% control of similar farm infestations, and so emphasized the need to continue baiting for longer periods.

The sources from which different ‘OH’ serotypes of Escherichia coli have been isolated are listed in a series of tables. It is considered that these tables should provide a basis for obtaining a greater understanding of the ecology of E. coli.

In the 15 months, February 1976 to April 1977, more than 241 patients became colonized with a strain of Klebsiella aerogenes, capsular serotype K2, resistant to most antibiotics. Urinary tract infection was the most common clinical manifestation but bacteraemia and, occasionally, infections of other sites were encountered. The main reservoir of the epidemic klebsiella was the gut, urine and skin of colonized patients. Gut carriage among staff was very uncommon. The most susceptible patients were elderly males, with debilitating illnesses and urinary tract abnormalities, especially if they were catheterized or receiving antibiotics. Likely vehicles for spread were the hands of staff, and contaminated bedpans and urinals. Control measures were directed at these factors. At the end of April 1977 no new cases had occurred for 3 months in the ward in which the outbreak began, and which had been the main focus of infection, and only 5 patients in the affected hospitals were known to be colonized by the epidemic klebsiella.

In these studies it is shown that the common ‘British’ and ‘American’ adult cockroaches can survive exposure to formaldehyde fumigation carried out at double the strength and for four times as long as is recommended for disinfection of rooms.

It is further reported that vaccinia virus ingested prior to the fumigation survives in the cockroach gut and may be excreted up to 5 days later.

Since cockroaches are ubiquitous and are to be found in most hospitals, laboratories and animal houses, these findings should be considered whenever fumigation is called for.

Adult cockroaches were found to survive up to 22 weeks when provided with 1% Formalin (0·4% formaldehyde) in lieu of drinking water. Given 4% Formalin or 2% glutaraldehyde they survived up to 41 days. During the experiments eggs were laid and hatched and the offspring continued to grow. Combined with surface disinfection, this may hold out a simple method of rendering adult cockroaches gnotobiotic or even axenic.

The normal flora of cockroaches (Periplaneta americana) was determined over a period of 24 days prior to substituting water with 1% Formalin for drinking water. During the first 4 days of treatment the normal flora was significantly reduced and by the fifth day, when the cockroaches became diarrhoeic, no bacteria, fungi, or viruses could be detected by the methods used.

Samples of 61 home grown and 199 imported vegetables of different varieties were examined for Escherichia coli, faecal streptococci and, when E. coli was present, for salmonellas. Eleven per cent of samples contained > 104E. coli per 100 g, and 14% > 106 faecal streptococci per 100 g. Salmonellas were isolated from 23 out of 103 samples examined.

Salmonellas were isolated from 8% of 76 samples with E. coli <104/100 g, but from 63% of 27 samples with E. coli exceeding 104/100 g; from 6% of 65 samples containing < 106 faecal streptococci/100 g but from 51% of 37 samples containing more than 106/100 g.

S. typhi was isolated from one sample of vegetables imported from the tropics. To our knowledge this is the first isolation of S. typhi from food in the Netherlands. Products from tropical countries were found to present the highest level of contamination. The hygienic quality of Dutch products is sometimes inferior to that of similar imported products, although the different seasons of sampling may have influenced the result. For the prevention of risk to the consumer of vegetables, good kitchen hygiene would appear to be the most important factor.

Poliomyelitis continued to be a rare disease in England and Wales in the period 1969–75. Only 31 paralytic and 44 cases of possible non-paralytic poliomyelitis were recorded during the 7 years.

Of the 31 paralytic cases approximately one third were vaccine-associated; 3 were patients who had recently received oral poliovaccine and 7 had been in contact with a vaccinated person. Five of these 7 patients were parents of recently vaccinated children. The rate of vaccine-associated poliomyelitis was estimated in recipients to be 0·2 and in contacts 0·4 per million doses of vaccine given.

Marker test results were reported on 555 strains of poliomyelitis virus isolated during 1969–75, using the reproductive capacity temperature test. Forty-eight (8·6%) resembled wild virus in this property, 15 strains being type 1, 8 type 2 and 25 type 3. Most of these isolations of apparently wild virus were from excreters with no symptoms of poliomyelitis, although 3 of the 15 type 1 strains were from patients with paralytic poliomyelitis and 3 from possible cases of non-paralytic poliomyelitis. None of the 8 apparently wild type 2 viruses was from a case of paralytic illness and only 1 of the 39 type 3 strains.

Eleven of the 31 paralytic cases were in patients in whom the infection was likely to have been acquired abroad.