Sera from 1661 persons in 12 age groups from 0 to 79 years were titrated for toxoplasma antibodies in the indirect immunofluorescence test. The sera were collected from patients with symptoms suggestive of acute, mainly respiratory, viral infections. After the first year of life, the prevalence of antibodies started to rise, reaching 59% between 40 and 79 years of age. From the prevalence of antibodies in different age groups the annual infection risk, i. e. the risk of a non-immune person acquiring toxoplasma infection, was estimated for successive age periods. The estimated annual infection risk increased from 0·5% in early childhood to 3% during adolescence and early adult life.

Approximately 70–80% of females entered the age of reproduction without evidence of seroimmunity to toxoplasma. The risk of primary infection during pregnancy was estimated from the age distribution of parturient women in The Netherlands in 1975 and the age-specific incidence of primary infections, i.e. the incidence in the total population of susceptible and immune persons. This incidence of primary infection decreased from 1·62% per 9 months at the age of 17½–20 years to 0·37% at the age of 35–45 years. The incidence of primary infections in pregnant women was estimated to be 1·25%.

Malignant catarrhal fever (MCF) herpesvirus was isolated from the nasal secretions of 4/11 young wildebeest calves. In two cases virus was demonstrated in filtered secretions. The presence of cell-free MCF virus would suggest that the virus can be transferred from wildebeest to wildebeest and into cattle in nasal secretions.

In a multi-laboratory trial with the mombrane filtration technique, three surfactants – Teepol 610 (T610), Tergitol 7 (T7) and sodium lauryl sulphate (LS) – were compared in media for the enumeration of coliform organisms and Escherichia coli in water. A total of 170 samples of water (87 raw and 92 marginally chlorinated) were examined for colony counts of coliform organisms, and 185 water samples (94 raw and 91 marginally chlorinated) for E. coli. Slight differences in the confirmed colony counts between the three media were noted, but few of these were observed consistently in every laboratory. In most laboratories, T7 gave slightly higher counts of E. coli than LS with chlorinated waters; a higher incidence of false-positive results for E. coli at 44 °C was also noted with T7. As there were no outstanding differences in the trial, sodium lauryl sulphate, which is chemically defined, cheap and readily available, is therefore recommended for use at a concentration of 0·1% instead of Teepol 610 in the standard medium for the enumeration of coliform organisms and E. coli in water by the membrane filtration technique.

The effectiveness of various hand washing and disinfection methods in removing transient skin bacteria was studied in hospital after dry or moist contamination of the hands when nursing burn patients. The results were compared with those of laboratory tests with volunteers. A fairly good correlation of the bacterial reductions existed between hospital and laboratory tests. All other methods removed Slaph. aureus from the hands more effectively than liquid soap. Gram-negative bacilli were more easily removed than staphylococci, even with soap wash alone.

In hospital, none of the washing and disinfection methods always removed all patient-borne bacteria from the hands. After dry or moist contamination and subsequent washing with soap only, colonies of Staph. aureus were often detected in finger-print samples. Staphylococci wero more often completely removed by a 4% chlorhexidine detergent scrub and alcoholic solutions (either with or without previous soap wash) than by liquid soap, hexachlorophene or iodophor preparations. Gram-negative bacilli were more easily removed by all the washing and disinfection methods. After moist contamination, Gram-negative bacilli were more often completely removed from the hands by ethanol than by other treatments.

The results of the present study emphasize the importance of always using gloves when nursing a profuse spreader of bacteria or one who must be protected from infection.

Pharyngeal micro-organisms of 131 Australian and Malaysian children and adults were compared by analysis of aerobic culture of throat swab specimens. Enteric Gram-negative bacilli were commonly isolated in small numbers from Malaysian adults whether they had sore throats (28%) or not (36%), but were detected in only 9% of Australian adults without sore throats and in only 12% and 4% of Malaysian children with and without sore throats respectively. In other respects microbiological findings were similar in the different groups of subjects studied.

It is concluded that the pharyngeal carriage rate of enteric Gram-negative bacilli may differ substantially between different groups of normal individuals. Our findings also suggest that these micro-organisms do not have a pathogenic role in pharyngitis.

Minced (ground) beef from three supermarkets, three intermediate-sized chain butchers and three small family butchers in each of three geographical areas was examined three times in warm weather and three times in cool. The total viable count (37 and 20°C), numbers of Enterobacteriaceae (37 and 17°C), and presumptive coliforms did not differ significantly between shop type or season. Statistically significant differences in numbers of faecal Streptococci, Staphylococcus aureus and Clostridium perfringens were too small to be of commercial importance, or diagnostic value.

A staphylococcal disperser employed as a theatre technician appeared to have been the source of 11 cases of wound sepsis over a period of about 3 years. He was primarily a nasal carrier and after attempts to eradicate Staphylococcus aureus from his nose failed, his skin dispersal was controlled by daily washing with 4% chlorhexidine detergent (‘Hibiscrub’) and he was allowed to resume his theatre duties under careful bacteriological surveillance. Over the following 2 years 173 dispersal tests showed a mean dispersal of 1·7 c.f.u. per 2800 I air compared with a mean of 152 c.f.u. per 2800 I air in the month immediately preceding treatment and 55 c.f.u. per 2800 I in the period after cessation of treatment. One case of wound sepsis was attributed to the technician during the 2 years in which he received skin disinfection treatment.

The toxicity and efficacy of the acute rodenticide scilliroside was evaluated in the laboratory against the lesser bandicoot rat, Bandicota bengalensis. The acute oral LD50 and LD 95 doses for males were 0·8 mg/kg and 2·5 mg/kg respectively, and for females were 0·5 mg/kg and 1·6 mg/kg, respectively. When caged bandicoots were given a choice between plain and poison baits, the optimum concentration of scilliroside was found to be 0·05%. Symptoms of poisoning appear from 22 to 34 min after feeding starts and the latency pattern indicated an abrupt ceasing to feed at these points. Death occurred from 2 h to as long as 6 days after poisoning, following prolonged convulsive seizures. There appears to be aversion to scilliroside at all concentrations in food baits. Maximum mortality attained on free-choice feeding on scilliroside was 90%. Despite these disadvantages, the material may have merit as an alternative rodenticide to zinc phosphide where acute toxicants are to be used.

Changes in the Danish BCG strain under certain regimens of subculture have been shown in preceding studies to be associated with selection of a minority population. Three Czechoslovakian BCG strains, all originally derived from the Danish strain but thereafter and in distinction from it maintained on potato media, have now been investigated. Changes in the immunizing potency of two of these strains have been attributed by other workers to employment of the richer potato media in place of Sauton medium as used for maintenance of the parent Danish strain. However, results from the present study suggest rather that selection of a pre-existing minority genotype or of a now mutant occurred. This proposal is supported by the finding that the third strain has maintained characteristics similar to those of the Danish parent despite many previous transfers on potato media.

Another BCG strain investigated was the Japanese which, like the three Czechoslovakian strains, had been previously maintained on potato media. This strain has been shown in the present study to resemble the Danish strain in supporting a minority population yielding non-spreading colonies. Czechoslovakian vaccine prepared with seed culture supplied from Tokyo has retained characteristics similar to those of the Japanese parent. Although a majority population yielding spreading colonies appears so far to have been retained in both centres, it is considered that selection of the minority could still occur in the course of routine transfer.

Nine caprine and ovine mycoplasma strains, said to be indistinguishable serologically from Mycoplasma mycoides subsp. mycoides (the causative organism of contagious bovine plouropneumonia; CBPP) were examined in mice by (1) a mycoplasmaemia test, and (2) a cross-protection test. Of the nine strains, two from goats belonged to a small colony (SC) type; four caprine and three ovine strains belonged to a large colony (LC) type.

The two SC strains – like a single SC strain examined in an earlier study – were indistinguishable from genuine M. mycoides subsp. mycoidesas isolated from CBPP. They produced mycoplasmaemia readily. In a cross-protection test, the two SC strains and a CBPP strain immunized completely against each other.

Of the seven LC strains, six – like six LC strains examined in an earlier study – were easily distinguished from genuine M. mycoides subsp. mycoides; except for one that was not tested, all were shown to lack the ability to produce mycoplasmaemia readily. In cross-protection tests all six strains immunized partially but not completely against a CBPP strain.

The soventh LC strain (Mankefár 2833) was exceptional: it produced mycoplasmaemia readily, resembling tho SC strains in this respect. Like other LC strains, in cross-protection tests it protected only partially against a CBPP strain. Strain Mankef´r 2833 was isolated in ca. 1005 by Brack from a Barbary sheep (Ammolragus lervia) in a German zoo.

The ability of Mankefár 2833 to produce mycoplasmaemia enabled it to be used as a challenge strain in cross-protection tests. For the purpose of such tests the collection of nine mycoplasma strains referred to above was augmented with six LC strains from an earlier study. Partial but not complete protection against Mankefár 2833 was produced by two caprine SC strains, one CBPP strain, and nine LC strains. Three further LC strains gave protection that may have been as strong as that produced by the homologous strain, but confirmatory experiments are needed. A strain of M. mycoides subsp. capri gave no protection against Mankefár 2833.

A total of 1590 calves were investigated between May 1972 and December 1975. Twenty-two per cent were treated for respiratory disease and 2·5% died of pneumonia. Almost 80% of the respiratory illness occurred in six sharp outbreaks. Samples for virology were collected routinely from 127 healthy calves and from 354 calves treated for respiratory signs and comprised 1143 nasopharyngeal swabs and 1069 sera. Virus infections were detected on 540 occasions including 135 by parainfluenzavirus type 3 (Pi-3), 78 by respiratory syncytial virus (RSV), 103 by rhinovirus, 49 by bovine virus diarrhoea virus (BVDV), 29 by adenoviruses, 53 by reoviruses and 88 by enteroviruses. The seasonal and age distribution of infections differed between viruses. Only infections by RSV, Pi-3 and BVDV were significantly associated with disease.

Soil samples from various parts of Britain were examined for Clostridium botulinum by a sensitive technique comparable with that recently used for mud samples from British aquatic environments. The results showed beyond doubt that in Britain the prevalence of the organism in soil is much lower than in mud. Of 174 samples from all sites examined only 10 (5·7%) could be shown to contain Cl. botulinum; this finding was consistent with the results of surveys made by less sensitive techniques in 1922, 1928 and 1942. No type other than B was found. The evidence suggested that in certain localized areas the prevalence was likely to be high.

Three sites associated for many years with animals were included in the survey; at the Zoological Society's premises at Regent's Park and at the Market paddocks, Gorgie, Edinburgh, the prevalence of Cl. botulinum was either very low, or nil. In an earlier survey of the redeveloped site of the former Metropolitan Cattle Market, London, 25% of soil samples gave a positive result and no less than four types (B, C, D and E) were demonstrated.

Of 17 pigs vaccinated with Streptococcus suis type-2 capsular polysaccharide plus Freund's Incomplete Adjuvant, all developed opsonizing antibody against Str. suis type 2. Of 14 pigs vaccinated with type-2 polysaccharide alone, 4 (possibly 6) developed opsonizing antibody. It is possible that some pigs vaccinated with polysaccharide plus Freund's Incomplete Adjuvant developed opsonizing antibody in response to a ‘booster’ injection of polysaccharide alone. Of 21 unvaccinated control pigs, late bleeding from 3 showed opsonizing activity against Str. suis type 2.

The family consisted of two parents and five children. While the father remained in Cardiff, the mother and all the children visited Rawalpindi, Pakistan, for 6 weeks to stay with relatives. Travel was by flight from Heathrow airport to Pakistan and by a short road journey to Rawalpindi. Mrs M. – the mother – as a guest, did no cooking on the holiday. The house which they were living in had a piped water supply, thought to be treated. There was no flush toilet but a commode was available and was emptied daily. All the children had gastro-enteritis symptoms for 2–3 days after arrival. Ru M. – a daughter – had the most severe illness and was treated by a local doctor. Diarrhoea in the three girls persisted on return to U.K. A faecal swab from Ru M. showed her to be excreting S. typhi (degraded Vi phage type). She was admitted to hospital. Faecal samples from the remaining members of the family were taken and examined for entero-pathogens. The father, Fa. M., who had not left Cardiff, had negative stools and remained free from infection. All other family members were excreting one or more enteropathogens, including a Campylobacter sp., three types of Sh. flexneri and one type of Sh. boydii. A subsequent faecal sample revealed that one of the male children, A.M., was excreting S. typhi phage type B2. The two typhoid infections were apparently unconnected.

Sixteen strains of Salmonella typhimurium phage type 179 were referred to the National Health Institute, Wellington, New Zealand, from 1977 to 1979. This phage type had not been observed here before 1977. All strains were resistant to ampicillin, several were also resistant to tetracycline, and several were resistant to ampicillin, tetracycline, sulphafurazele and trimethoprim. All resistances could be transferred to Escherichia coli K 12. Plasmids from these strains and their transconjugants were characterized by agarose gel electrophoresis. It appears that resistance to sulphafurazole and trimethoprim is carried on a plasmid with a molecular weight of 5·2 Mdal and that resistance to ampicillin and tetracycline is carried on a plasmid with a molecular weight of approximately 60 Mdal.

Strains of Staphylococcus aureus were isolated at a single sampling from cows in a dairy herd. When typed by phage most showed a complex pattern of lysis with group III and IV phages. Cross-spotting of strains showed great lytic activity and ten phages were isolated. The parent strains were lysogenized with these phages and the effect on the phage typing pattern of 202 daughter strains from 25 parent cultures was studied. Phage action was often blocked completely, with up to four being blocked on the one strain. Those most frequently blocked were phage 101, 117, 307 and 42D.