Eight monoclonal antibodies have been derived from Balb/e mice hyperimmunized with the purified flagella from Campylobacter jejuni strain 81116. These monoclonal antibodies are directed against flagella as demonstrated by reaction in ELISA against flagellate and aflagellate antigens, radio-immunoprecipitation and electro-immunoblotting techniques. Some of the antibodies react with a 60K minor protein as well as the 62K flagella protein. This protein may be related to an antigen expressed on the surface of the organism and detectable by immunogold labelling with one of the monoclonal antibodies.

None of the antibodies causes the aggregation of bacteria or inhibits bacterial motility, unlike polyclonal anti-flagella antiserum. Moreover, none of the antibodies tested protected infant mice from colonization with C. jejuni strain 81116 even though partial protection (28%) was observed with syngeneic anti-flagella antiserum. Absence of protection is probably due to the cryptic nature of the flagella epitopes investigated or lack of antibody activity in the gastrointestinal tract.

Intraperitoneal vaccination of female mice, before mating, with a whole cell, heat-killed (62 °C) vaccine of Campylobacter jejuni allowed the mother to confer immunity to her young, challenged orally 4–6 days after birth with the homologous strain. There was no protection against a strain of another serotype. Heating the vaccine to 100 °C destroyed its protective properties. A vaccine prepared from an anagellate variant of the original strain was as protective as the original vaccine against challenge with the flagellated strain. Anti-flagellar serum antibody titres of the dams did not correlate with protection of their young.

The role of broiler eggs in the transmission of Campylobacter jejuni to broiler grow-out flocks was investigated. Six breeder flocks supplying broiler eggs to hatcheries were examined for cloacal carriage of C. jejuni. Of 240 birds tested, 178 (74%) were C. jejuni-positive. Eggs from these birds examined for C. jejuni penetration of the egg shell indicated that 185 of 187 were campylobacter-free. Eggs from breeder flocks of unknown C. jejuni status were also examined for C. jejuni shell penetration. C. jejuni was not isolated from 142 eggs examined. A further 193 hatchery eggs incubated and hatched in the laboratory were campylobacter-free. Six farms containing the progeny of C. jejuni-positive breeder flocks were monitored. Eight hundred and forty birds from 14 flocks m these grow-out farms were campylobacter-free during their 6-week grow-out period. Experimental egg-penetration studies indicated that C. jejuni transmission via the egg is not easily effected. Of 257 eggs surface-challenged with C. jejuni, 162 hatched; all were campylobacter-free. Of 167 eggs injected with C. jejuni, 12 hatched; 2 of these were colonized with C. jejuni. Our data do not support a role for vertical transmission of C. jejuni in commercial broiler production.

Simultaneous oral administration of broth cultures of three strains of Escherichia coli isolated from sewage and an abattoir strongly inhibited the colonization of a subsequently administered strain of Salmonella typhimurium. The three strains were protective against the S. typhimurium strain under a variety of conditions: in different breeds and in chickens fed different diets. The strains were not equally effective against other salmonella strains. Oral administration of the strains produced a statistically significant reduction in the excretion of the S. typhimurium strain over a period of 7 weeks.

Susceptibility studies were undertaken to determine the response of some South African wild rodent species to experimental plague (Yersinia pestis) infection.

A degree of plague resistance was found in three gerbil species captured in the plague enzootic region of the northern Cape Province, these being the Namaqua gerbil, Desmodillus auricularis, (LD50 1 × 106 organisms), the bushveld gerbil, Tatera leucogaster, (LD50 9·1 × 105) and the highveld gerbil, T. brantsii (LD50 4 × 102). Animals from a population of the four-striped mouse, Rhabdomys pumilio, captured in the plague area of Port Elizabeth, proved moderately resistant to experimental plague infection (LD 50 1·3 × 104) while those from another population of the same species captured in a plague-free area of the Orange Free State were extremely susceptible (LD50, 5 organisms). The response of both populations however was a heterogeneous one. Marked differences in susceptibility were also found between two populations of multimammate mice, Mastomys natalensis (2n = 32) although both originated from areas outwith the known distribution of plague in southern Africa.

The 50% infectious dose was relatively high in T. leucogaster (3·2 × 102) and D. auricularis (1·7 × 103), but was low (2–16 organisms) in the other rodent species tested.

The plague antibody response, determined by enzyme-linked immunosorbent assay (ELISA), was extremely short-lived in T. leucogaster, only 10% of inoculated animals remaining seropositive at low titres after 11 weeks. Antibodies persisted for only slightly longer in the sera of T. brantsii which were reinoculated with 2 × 103 plague organisms 6 weeks after initial challenge.

The demonstration of the existence of both susceptible and resistant populations of R. pumilio and M. natalensis indicates that these species must be considered as potential plague reservoir hosts in parts of South Africa.

The results suggest that resistance to plague infection in previously epizootic hosts in the northern Cape Province such as Tatera sp. and D. auricularis has arisen through continual selective pressure of the organism. If the findings are applicable to gerbil populations in other plague enzootic regions of South Africa it is probable that acquired plague resistance has been responsible for the absence of gerbil epizootics and consequently for the dramatic decline in human plague outbreaks in South Africa since 1950.

A disinfectant (2,4,4′-trichloro-2′-hydroxydiphenyl ether: Irgasan, Ciba-Geigy) was incorporated into plastic washers fabricated from ethylvinyl acetate (EVA), polyethylene, polypropylene or TPX. Plastics containing 0·2 and 2% Irgasan gave zones of inhibition on nutrient and blood agar plates seeded with micro-organisms (Staphylococcus aureus, Staph, epidermidis Escherichia coli, Proteus mirabilis or Candida albicans) even after thorough washing. Exceptionally, C. albicans was inhibited only by 2% Irgasan, and EVA gave good inhibition only against the staphylococci. Similar washers of each plastic were implanted subcutaneously into the flanks of rabbits; before insertion each was washed, had thread woven into it and was surrounded by a plasma clot containing 2 × 108Staph. aureus. All the plastics without Irgasan gave rise to abscesses, none of the plastics impregnated with 2% Irgasan did, though from 2 out of 12 sites small numbers of Staph. aureus were isolated at post mortem. Using either clinical or bacteriological criteria, the results were highly significant (P < 0.00001 and P <0.001 respectively), demonstrating the effectiveness of this technique in preventing plastic-associated infection.

Dilution had an adverse effect on the infectivity of 24 h cultures of a strain of Fusobacterium necrophorum, which became apparent at or near the minimum lethal dose. Thus in mice inoculated subcutaneously the mortality produced by 0·01 ml of undiluted culture was almost invariably greater than that produced by 0·1 ml of a 1 in 10 dilution. The explanation appeared to lie in the increased physical separation of bacterial cells that was the inevitable consequence of dilution.

The bacterial status of beef carcasses at a commercial abattoir was monitored before and after slaughterline automation. Bacterial counts did not differ significantly overall (P>0·05) between the original manual line and the automated line for either morning or afternoon slaughter. On the manual line counts in the morning were lower than those from carcasses slaughtered in the afternoon, but on the automated line there was no difference between morning and afternoon counts. Due to highly significant line × sample site interaction for both morning and afternoon counts, overall differences among sample sites were not found by analysis of variance. However, principal components analysis revealed a significant shift in bacterial contamination among some sites due to slaughterline changes. The incidence of Enterobacteriaceae increased marginally following automation.

Methicillin-resistant Staphylococcus aureus (MRSA)strains present an increasing clinical problem. Analysis of 2679 strains submitted to a reference laboratory in the first quarter of 1983 and 3050 strains submitted in summer 1984 showed 479 and 593 multi-resistant strains. The proportion of methicillin-resistant strains classified as epidemic rose from 5·9 to 10·2%. Other methicillin-resistant strains continued to occur but other methicillin-sensitive multi-resistant strains appeared to fall. A strain with defined characters could be recognized in the Thames regions.

The cellular fatty acid composition of 41 strains of suspected Campylobacter jejuni, 23 from human cases of gastroenteritis and 18 from animals, was examined by gas-liquid chromatography. Three of the 23 human isolates and 2 of 18 animal isolates did not contain 19:0 cyclopropane fatty acid and were identified as C. laridis. The remaining 36 strains had cellular fatty acid profiles consistent with C. jejuni but could be divided into three groups on the ratio of the concentration of 18:1 and 19:0 eycloproprane. Most human isolates (85%) were in groups II or III whereas most animal isolates (56%) were in group I. It is proposed that gas-liquid chromatographic analysis of cellular fatty acids is a relatively easy method for epidemiological typing of C. jejuni isolates.

In developing countries tuberculous meningitis is a difficult infection to differentiate from other central nervous system (CNS) infections. This paper presents the history, physical findings, laboratory data, and clinical course of 100 patients who were admitted to a special ward and had CSF cultures positive for Mycobacterium tuberculosis. Fifty-four patients were comatose when admitted and 76 had meningeal signs. Mean admission CSF values were WBC 531, glucose 23 mg/dl, and protein 166 mg/dl. Only two CSF AFB smears were positive. Sixty-one percent of the chest X-rays taken were consistent with pulmonary tuberculous and 39% were normal. Twenty-four patients died within the first week after admission, before the clinical diagnosis was made and anti-tuberculous therapy could be started. Fifty-three of 76 patients given antituberculous therapy died. Neurologic sequelae developed in 48% of the survivors. The high mortality and morbidity rates in this patient-group were due to the severity of illness on admission and the predominance of children (54%).

Water samples from home filters in nine residential areas of a Nigerian university community were studied. The membrane filter technique was used to determine the total coliform and faecal coliform counts/100 ml of water. Most of the 100 samples studied were grossly contaminated with total coliform counts/100 ml ranging from 0–442, faecal coliform counts/100 ml, 0–216 and the total aerobic plate count per millilitre ranged from 3·0 × 103 to 1·9 × 109 c.f.u. The source (dams) of water, fitness of filter candles, frequency of cleaning candles and pH of water did not significantly (P > 0·05; X2) affect the microbial quality of either filtered boiled or unboiled tap water.

Escherichia coli type I was isolated from 17·9% of the faccal coliforms tested but from only 2·3% of total coliforms. Enterobacter aerogenes was most predominant (38·5%) amongst faecal coliforms isolated while Enterobacter cloacae was the most frequent (37·2%) of the total coliform isolates.

The gross contamination of filltered water from all households sampled calls fpr am englightenment of residents on the proper use of home water filters.

The sera of healthy blood donors from the Wellington area of New Zealand, collected between 1976 and 1980, were analysed by the complement fixation test for antibody to Mycoplasma pneumoniae. A high prevalence of antibody to this organism was demonstrated and the occurrence of an M. pneumoniae epidemic in New Zealand within the survey period was shown to be reflected i the immune status of this healthy adult population. This would suggest that during an epidemic many people within the Wellington community may have M. pneumoniae infections involving littl overt illness.

Forty-six gnotobiotic calves aged less than 16 days or 42–116 days were infected with three strains of bovine rotavirus designated C3–160, CP-1 and PP-1. Each virus was passaged and cloned in cell culture (cloned viruses) but CP-1 and PP-1 Were also used before culture (faecal viruses).

Infection of calves aged less than 16 days with faecal or cloned CP-1 caused disease whereas cloned C3–160 and faecal or cloned PP-1 caused subclinical infections. The clinical signs of disease were change in faecal colour to pale yellow or cream, increase of 2- to 7-fold in the volume of faecal output and, usually, anorexia. With the virulent CP-1 virus and the avirulent C3–160, similar amounts of virus were excreted in the faeces for 4–6 days.

Infection of calves aged 56–116days with faecal CP-1 produced disease of similar severity to that seen in calves aged 7–10 days infected with the same virus. No differences in clinical signs, virus excretion or levels of convalescent antibody were seen between the two groups. With cloned CP-1, 5 of 8 older calves developed disease but 3 showed only mild signs of infection.

It was concluded that two strains of rotavirus caused sub-clinical infections in young calves while a third was virulent in calves up to at least 116 days of age.

The epidemiology of human rotavirus (HRV) in north-east Scotland was investigated between 1982 and 1984. During this period 708 HRV infections were recorded. The majority (83%) of the infections were in children less than 5 years of age although some were recorded in adults. The peak incidence occurred in the winter months although a high number of HRV infections was reported during the summer of 1983. A total of 840 faecal specimens containing rotavirus were screened for HRV genome RNA by polyacrylamide gel electrophoresis. Seven hundred (83%) specimens gave RNA profiles suitable for establishing the HRV electrophoretype. Twenty-five different electrophoretypes were identified, of which 21 had ‘long’ RNA profiles and four had ‘short’ RNA profiles. There was extensive co-circulation of distinct electrophoretypes although during any one epidemic period the majority of viruses belonged to a relatively small number of types. Comparison of viruses collected from hospitalized and non-hospitalized Patients showed no differences in electrophoretype distribution. HRV was identified in faecal specimens from a wide age group and no correlation was demonstrated between age of patient and electrophoretype of the infecting virus.

To assess the potential of fomites and environmental surfaces as vehicles in the transmission of rotaviral diarrhoea, disks (1 cm diameter) of various porous and non-porous materials were contaminated with about 105 plaque-forming units of the Wa strain of human rotavirus (HRV) suspended in faecal matter. The contaminated disks were then held for 10 days at either room temperature (22±2 °C) or 4°C with the relative humidity (RH) at the high (85±5%), medium (50±5%) or low (25±5%) level. Survival was longer on non-porous surfaces at the lower temperature and at lower humidity. In contrast, survival on porous surfaces was very variable; better on cotton-polyester than on poster card or paper currency on which HRV survived very poorly. These results suggest that under the right environmental conditions, HRV-contaminated objects could play a role in the transmission of rotavirus infections in hospitals, nursing homes and day-care centres.

Analyses of data collected in a large survey (sample size > 3000) of rubella antibody in South East England, finely stratified according to age, reveal age-dependent changes in the pattern of virus transmission. The rate or force of infection changes from low in the young children to high in the 5 - to 15-year-olds and back to low again in the adult age classes (there is a 50% reduction between the 5- to 15-year-olds and the 20+-year-olds). Raised levels of immunity are recorded in the teenage and young adult female segments of the population as a consequence of the UK rubella immunization programme. Mean antibody concentrations show a decline with age and are, on average, lower in vaccinated females when compared with unvaccinated males of the same age. The interpretation of horizontal cross-sectional serological data and future research needs are discussed.

The paper examines predictions of the impact of various one-, two- and three-stage vaccination policies on the incidence of congenital rubella syndrome (CRS) in the United Kingdom with the aid of a mathematical model of the transmission dynamics of rubella virus. Parameter estimates for the model are derived from either serological data or case notifications, and special attention is given to the significance of age-related changes in the rate of exposure to rubella infection and heterogeneous mixing between age groups. Where possible, model predictions are compared with observed epidemiological trends.

The principal conclusion of the analyses is that benefit is to be gained in the UK, both in the short and long term, by the introduction of a multiple-stage vaccination policy involving high levels of vaccination coverage of young male and female children (at around two years of age) and teenage girls (between the ages of 10–15 years), plus continued surveillance and vaccination of adult women in the child-bearing age classes. Model predictions suggest that to reduce the incidence of CRS in future years, below the level generated by a continuation of the current UK policy (the vaccination of teenage girls), would require high rates of vaccination > 60%) of both boys and girls at around two years of age. Numerical studies also suggest that uniform vaccination coverage levels of greater than 80–85% of young male and female children could, in the long term (40 years or more), eradicate rubella virus from the population. The robustness of these conclusions with respect to the accuracy of parameter estimates and various assumptions concerning the pattern of age-related change in exposure to infections and ‘who acquires infection from whom’ is discussed.

Three outbreaks of influenza caused by influenza A H1N1 occurred in a boys' boarding school in 1978, 1979 and 1983. The serological response to infection with variants of the H1N1 virus was studied by radial haemolysis and haemagglutination inhibition after primary infection and reinfection. The persistence of this antibody was also studied. Infection in 1978 resulted in the production of persistent antibody to both the haemagglutinin and neuraminidase of the homotypic strain. Antibody which cross-reacted with later variants of the virus was less frequently produced, the peak response was delayed and such antibody persisted less well. Infection in 1979 resulted in a similar response to that observed in 1978 after primary infection. Reinfection resulted in a broad response in all cases. In 1983 all infected boys produced antibody which reacted with the homotypic strain but only approximately one-third of primary infections produced antibody which reacted with the A/USSR/92/77 strain. The neuraminidase of the A/USSR strain failed to detect one third of the primary infections. Reinfection again resulted in a broad response.

Following its reintroduction in 1978 influenza A H1N1 spread widely in the child population. By the autumn of 1979, 75% of 11-year olds entering a boys' boarding school had detectable antibody. The protective effect of previous experience could be assessed during two outbreaks in the school. In the first outbreak in 1979, 90% of those known to have been infected in the previous year were protected against reinfection. In 1983 after strains of the H1N1 subtype had undergone antigenic drift a large outbreak occurred. It was estimated that past infection conferred protection against clinical influenza in 55%. Where past infection resulted in the presence of antibody which reacted with the outbreak strain the attack rate was further reduced. A large number of sub-clinical infections was detected in all groups.