In a Dutch population group neutralizing antibodies against mumps virus were determined by a plaque reduction technique, which proved reproducible, sensitive and specific. The results with sera of about 800 suburban children show that mumps is acquired at an early age with peak acquisition rates between the ages of four and six years. Over 90% have acquired mumps before the age of 14 years. More than 95% of about 1000 adults (18–05 years) have neutralizing antibodies. The relatively constant median titre suggests that antibodies persist during life.

During a family study 77 clinical and 18 subclinical cases were observed. In families with index cases the attack rate was 26/37 = 0·71. Eleven children (excluding six babies) esćaped infection. The mean attack rate during the epidemic was 0·30. The mean titre of mumps neutralizing antibody is maximal during the first year after the disease but declines during childhood. Mothers exposed to mumps in the family occasionally showed a significant rise in titre. Some seronegative mothers remained seronegative after exposure.

During an outbreak of food poisoning at a church camp, 16 of the 25 people attending were affected. Despite a thorough search for a bacterial pathogen none was identified. An examination of the Escherichia coli serotypes present suggest that E. coli 0159.H9 may have been the organism causing the outbreak.

In 1972 more than 20% of boys admitted to a closed community (Junior Detention Centre) developed acute tonsillitis and group-A streptococci were isolated from more than 40% of all boys at some time during their stay of two months. The most common serotype was M-type 5, which has frequently been associated with rheumatic fever in other epidemics; four cases of rheumatic fever occurred between 1972 and 1977. Various methods were tried to eliminate the infection, but only full penicillin prophylaxis (0·25 g oral penicillin 4 times a day for 10 days) to all boys on entry appeared to be effective.

In a sample of cases of acute tonsillitis, group-A haemolytic streptococci were isolated from 31·7% by the use of dry swabs or unenriched transport medium, but with enrichment medium duplicate swabs, 77·0% yielded positive results. We question the current practice in some laboratories of reporting positive cultures only when more than ten colonies of β-haemolytic streptococci are present. In this survey viruses did not appear to be an important cause of acute tonsillitis.

High titres of streptococcal antibodies (antistreptolysin O, anti-desoxyribonuclease B and anti-M associated protein) were found, not only in cases and carriers, but in boys on entry to the centre. This supports epidemiological evidence that adolescent boys on entry to the centre. This supports epidemiological evidence that adolescent boys are particularly prone to streptococcal throat infections.

Over a four-year period 878 samples of faeces were collected from five species of small wild rodents and two species of shrews at sites in England, Scotland and Wales. A search was made for Salmonella in these samples but no isolations of this genus were made. Several other genera of Enterobacteriaceae were identified.

Bacteriostatic activity was measured in 244 specimens of milk collected during 1977 throughout lactation of up to one year from 78 mothers; the activity varied from very good to fair and only seven were inactive. There was a wider range of activity than was found previously in milk from English mothers. Activity usually fell slowly during lactation but some of the Gambian mothers produced milk of very high activity, like that of colostrum into the second week of lactation, and two mothers did so at six and nine months; other mothers produced good-activity milk throughout lactation. The bacteriostatic activity varied little with the season but slight decreases from that expectcd were found after the high incidence of infant diarrhoea towards the end of the rainy season.

The bacteriostatic activity of most of the milk tested could be prevented by iron salts but that of colostrum and some of the milks with high activity could not. Only these highly active colostra and milks were inhibitory in vitro when the inoculum was increased from 104 to 106 organisms per ml. These and less active milks were able to inhibit the smaller, standard inoculum for longer than 3 h with the addition of bicarbonate and extra iron-binding protein at the concentrations likely to be present in vivo. Both commensal and pathogenic E. coli were inhibited to a similar degree by these milks and there was no evidence of serotype specificity.

Investigations were conducted between 1977 and 1979 to assess the performance of microbiological tests for detecting and identifying residues of therapeutic-type antibacterial substances in meat and offal. Of the 5442 home-produced meat samples examined, 34 (0·63%) showed inhibitory activity in the screening test, which used Bacillus subtilis BGA and Micrococcus luteus as indicator organisms. Identification by electrophoretic and thin-layer chromatography/bio-autography techniques confirmed that only two of the 34 screen failures were due to true antibacterial residues: a pig sample contained a trace of penicillin and a horse sample contained a trace of an incompletely identified substance resembling a tetracycline. Twelve of the other 32 failures in the screen test were due to naturally produced inhibition and were, thus, falsely positive, whilst the remainder were shown to be negative. All of the 85 (8·7%) screen test failures from the 972 imported meat and offal samples tested were falsely positive. Additional samples from certain animals known to have been given antibiotic treatment were tested concurrently to give a more searching indication of screen and identification test efficacy.

Several sites on commercial beef, pork and lamb carcasses were sampled at the end of the slaughterline. Total viable counts (TVC) of bacteria were assessed by incubation at 37, 20 and 1 °C in addition to presumptive coliforms (PC), Enterobacteriaceae (ENT) and faecal streptococci (FS). Statistical analyses showed consistently dirty sites within an abattoir but these sites varied from one abattoir to another. Inter-site differences were unaffected by the incubation temperature of the TVC. Numbers of PC, ENT and FS did not mimic TVC. Empirical sampling plans are proposed to detect the highest count on a carcass by bulking samples from known dirty sites. At the end of the slaughterline TVC 37 °C is the most useful bacteriological index.

We have tried to measure the incidence of prenatal infection in 304 infants whose mothers had had rubella at various times after the first 12 weeks of pregnancy. Two methods of assessment were used: first, serum obtained soon after birth was tested for specific IgM antibody; secondly, serum obtained after the age of eight months was tested for specific IgG. When maternal rubella occurred 12–16 weeks after the last menstrual period specific IgM antibody was detected in 28 out of 50 infants (56%). The proportion fell progressively to 12% after maternal rubella at 24–28 weeks, rose to 19% after rubella at 28–36 weeks and then to 58% when the illness occurred during the last month of pregnancy. In all, IgM antibody was detected in 77 out of 260 infants (29%). The fetus can thus be infected at any time during the second and third trimesters of pregnancy, but the risk varies at different stages.

The figures for the prevalence of IgG antibody were greater throughout, because some infants had IgG who had previously lacked specific IgM. After maternal rubella at 12–16 weeks IgG antibody persisted in 22 out of 31 infants (71%). The proportion fell to 28% after rubella at 24–28 weeks and then increased progressively to 94% after rubella during the last month. In all, IgG antibody persisted in 94 out of 190 infants (49%). The true rate of fetal infection probably lies between the rates estimated from the presence of IgM antibody and the subsequent prevalence of IgG.

Infants whose mothers had rubella at any time during pregnancy should be examined regularly for possible evidence of damage.

A method is described for comparing the resistance to penetration by aqueous fluids, under rubbing contact, of a representative series of fabrics. Untreated woven fabrics are rapidly penetrated, but some non-woven synthetic materials resist penetration for much longer and tightly woven proofed cotton fabrics for prolonged periods, even after repeated washing and sterilizing. If a wetting agent is added to water, penetration occurs more quickly, but fabrics containing natural cotton are penetrated more slowly by serum.

The same fabrics were examined by a test designed to simulate transfer of dry participate material, e.g. skin scales, through them during nursing contact. The proportionate differences observed were much greater than for air dispersal during exercise and closely resembled those obtained by a laboratory rubbing test. In particular, one of the non-woven fabrics showed much greater relative penetration when examined by these methods than the relative dispersal of skin scales through it during exercise.

A one-year field-study has been carried out in a diarrhoea-endemic area in West Africa to determine the relationship between the bacteriostatic activity of fresh human milk for Escherichia coli in vitro and freedom from diarrhoea of the infant recipients of the milk. The specific contribution of E. coli gastroenteritis to gastrointestinal diseases of infants in general is not known, nor is its particular role in the Gambian infants studied. During the study period, however, both enteropathogenic and toxigenic strains of E. coli were isolated.

The incidence of diarrhoea in Gambian infants of seven age-groups from 2 days to 12 months was not significantly correlated with the bacteriostatic activity of milk. This was due rather to absence of diarrhoea in babies fed on low-activity milk than illness in those receiving highly bacteriostatic milk. Indeed, very active milk appeared to protect recipients almost completely, including seven babies of over 3 months of age, five of them during the rainy season, when the risk was high. Babies receiving lower-activity milk experienced more diarrhoea. In a situation where diarrhoeal disease is multifactorial, field evaluation of the protective action by one antibacterial property of milk is difficult. A better understanding of in vivo protection is important, and the factors which have to be taken into account are discussed.

The purpose of this paper is to draw attention to the fact that W. S. Greenfield, working at the Brown Animal Sanatory Institution in London, prepared an effective vaccine against anthrax and described his results some months before the experiment of Pasteur at Pouilly-le-fort. Partly through lack of financial support and partly due to opposition by the antivivisectionists, Greenfield was forced to confine his experiments to a small number of animals, but his results were nevertheless conclusive. He showed that by continuous subculture in a fluid medium that the anthrax bacillus progressively lost its virulence, until it was harmless even to the most susceptible animal, the mouse. The injection of suitably attenuated organisms into cattle rendered them immune to the subsequent injection of virulent anthrax bacilli. Greenfield's work has been overlooked or neglected, and he has never received the credit due him. It is only fitting that his work should be acknowledged in the centenary of the year in which it was described. The following account is composed primarily of quotations from his published papers. For additional information on Greenfield, reference may be made to the scries of papers by Wilson (1979a, b). It may be pointed out that the method of attenuating the virulence of bacilli recorded by Pasteur in relation to the bacillus of fowl cholera was, like that of anthrax vaccine, anticipated by Greenfield.

Individually caged northern palm squirrels, Funambulus pennanti, were fed with bait containing 0·025% warfarin or fumarin, 0·0075% chlorophacinone or 0·005% brodifacoum for a fixed number of days varying from 1 to 14. Brodifacoum (WBA 8119) was found most toxic since 66% and 70% of the animals died after one and two days' feeding respectively. Chlorophacinone killed 70% of the squirrels after three days' feeding. Squirrels were relatively tolerant to warfarin and fumarin since the mortality after a period of 14 days' feeding was only 58% and 75% respectively.

The cultural characteristics of 1220 Campylobacter strains from a variety of sources are described. Forty-two were identified as Campylobacter fetus ssp. fetus (Véron & Chatelain, 1973), 1120 as members of the C. jejuni/C. coli group, and 58 did not conform to any known description. Sixteen of the latter strains had the basic characteristics of C. fetus but were atypical in certain other respects. The other 42 strains had the thermophilic characteristics of the jejuni/coli group, but were resistant to nalidixie acid and had other features in common; it is possible that they represent a new species. They were isolated from 19% of locally caught wild seagulls but only occasionally from other animals and man.

Growth at 25 °C clearly distinguished strains of C. fetus from those of the jejuni/coli and the nalidixie acid-resistant thermophilic (NARTC) groups. Maximum growth temperature was less reliable for this purpose, and 43 °C was found to be better than the traditional 42 °C. By arranging the results of three tests (tolerance to 2,3,5-triphenyltetrazolium chloride, growth at 30·5 and 45·5 °C) serially in the form of a schema comprising nine categories, the jejuni/coli strains fell into two main groups resembling the Institute Pasteur C. jejuni and C. coli type strains, but these groups could not be clearly defined owing to the existence of strains with intermediate characteristics.

Most of the strains from cattle resembled C. jejuni, whereas those from pigs resembled C. coli; poultry strains occupied a more intermediate position. Strains from man and other animals were of mixed types, but most human strains resembled C. jejuni rather than C. coli. The type distribution pattern that most nearly matched that of human indigenous strains was given by a half-and-half mixture of strains from cattle and poultry.

The efficacy of seven rodenticides for use against Sigmodon hispidus was investigated in the laboratory. The poisons (warfarin, coumatetralyl, difenacoum, brodifacoum, bromadiolone, calciferol and zinc phosphide) were all toxic at the concentrations normally used against Rattus rattus and R. norvegicus and all were palatable.

Trials are now needed to confirm the efficacy of these poisons in the field, but it seems likely that, if used in suitable bait formulations, they would all be useful for the practical control of S. hispidus.

The changing seasonal patterns of reported measles cases in Iceland during this century are analysed. These changes are related to increased population mobility following the development of external and internal transport links, particularly since 1945. The forging of such links has resulted in a shift in the seasonal distribution of cases from one peculiar to the local social and economic conditions in Iceland to one broadly similar to that in other countries of northern temperate latitudes.

Åke Cederberg and Kai Österberg

J. Hyg., Camb. (1980), 84, 321–30

Figures 5 and 7 are transposed. Tho figure legends are correctly numbered.