Great strides have been made towards the control of poliomyelitis since the introduction of the two poliovaccines – inactivated poliovirus vaccine (IPV), which was licensed in the United States in 1954, and live attenuated oral poliovaccine (OPV), in 1961. Today a large majority of physicians and other health–care workers in industrialized countries never see a patient with paralytic poliomyelitis. Unfortunately, this is far from the situation in many developing countries, particularly in tropical and subtropical climates, where hundreds of thousands of children still become paralysed victims, year in and year out.

Epidemiological features of an outbreak of group B:15:P1.16 meningococcal disease (MD) in Frederiksborg country, Denmark, 1987–9, were investigated. The study comprised 149 cases notified during the outbreak and the two preceding years; 115 were confirmed by the isolation of Neisseria meningitidis. In 1989 the incidence had increased to 14·1 per 100 000 population. Among group B strains, B:15:P1.16 accounted for 80% (77/97). The overall mortality rate was 10% (15/149). Regarding cases due to group B:15:P1.16 strains a significant time-space clustering, which exclusively occurred within the 10–19 years age group, was demonstrated. The link between cases within clusters was indirect or unknown, except for ten patients with contact to one particular school. The prophylactic measures used included administration of rifampicin to household contacts. During the outbreak the proportion of secondary cases was high (6–15%). All secondary cases occurred outside the household indicating that the household had been protected.

Multilocus enzyme electrophoretic analysis was employed to assess the genetic relatedness of Neisseria gonorrhoeae. Based on the diversity of electromorphs at 9 enzyme loci, 16 electrophoretic types (ETs) were estabilished amongst the 65 isolates. The average number of alleles per enzyme locus was 1·7 and the mean genetic diversity per locus was 0·212. The majority of isolates belonged to either ET1 (32·3%) or ET2 (16·9%). No specific correlation of ETs was seen with serovars as the major types, ETs 1 and 2, were found distributed amongst the various serovars. Major serovars such as Bacjk (IB-1/2) and Bajk (IB-3/6) were each represented by 6 or 8 ETs respectively. Analysis of the genetic relationships of ETs to each other showed some clustering of subgroups that were more closely related than others.

Fifty–two strains of Helicobacter pylori were examined by DNA restriction endonuclease digestion, ribosomal (r)RNA gene probe hybridization and bio–typing. Most (49) strains originated from gastric (antral) biopsies of patients before or after elective surgery for duodenal ulcers. Chromosomal DNA Hind III ribopatterns showed 9 strain clusters of which the largest contained 12 strains each with 3 common bands (1·50, 3·45, and 4·26 kb) but which were heterogeneous with respect to biotype and total digest pattern. Isolates from post–operative patients with either healed or recurrent ulcers showed ribopattern heterogeneity and exhibited a similar distribution of H. pylori ribopattern types; no single type predominated in any patient group or was more highly associated with recurrent ulcers than with healed ulcers. Multiple isolates from two surgical patients had only minor genomic variations in each set whereas isolates from two brothers had different ribopatterns. We conclude that Hind III ribopatterns in conjunction with total digest patterns might provide the basis for future epidemiological typing studies.

A 12-month survey on the incidence of campylobacter infection in 1217 patients with diarrhoea was carried out in Jeddah, Saudi Arabia. Campylobacters were isolated from 55 (4·5%) patients, second in prevalence to salmonellas (6·2%). Shigellas were isolated from 4·2% of patients. Campylobacter isolation rates were high in children of all ages, as well as in young adults (36·5% of all isolates were from adults aged 20–39 years). Isolation rates peaked in September and November. Analysis of the results showed that 69% were Campylobacter jejuni (mostly biotype IV) and 31% C. coli. Serogroups 5 and 23 (Penner scheme) and phage type 125 (Preston scheme) were most frequently isolated. Resistance to erythromycin and tetracycline was observed in 7·3 and 32·7% of the isolates. Campylobacters are an important cause of bacterial enteritis in Saudi Arabia, both in adults and in children, and should be sought routinely.

Salmonella arizonae are rarely isolated in the UK. Since 1966 there have been sixty-six isolates from humans of whom 35% gave a recent history of foreign travel. Terrapins and snakes are potential sources of infection.

Infectious diarrhoea is common in young Australian Aborigines [1–3] and is one of the main causes for their unsatisfactory health standards with consequent widespread failure to thrive and undernutrition [4–5]. Most published reports relate to patients in hospital or to hospital admission statistics and give little indication of the extent or severity of diarrhoeal disease in children in Aboriginal communities.

The present investigation involved more than 100 Aboriginal children up to 5 years of age living in remote communities in the tropical north of Western Australia who were studied prospectively over a 12–month period.

Sera from ten patients with positive brucella serology were used to investigate antibody cross-reactions between the O-antigens of Escherichia coli 0157 and Yersinia enterocolitica 09. SDS-PAGE profiles of lipopolysaccharide (LPS), purified from strains of E. coli 0157 and Y. enterocolitica 09, were reacted with sera by immunoblotting. All ten sera contained antibodies which bound to the LPS of E. coli 0157, and five of these sera also contained antibodies which bound to the LPS of Y. enterocolitica 09. Absorption studies using these five cross–reacting sera indicated the existence of at least three epitopes exposed on the O–antigens of E. coli 0157 and Y. enterocolitica 09. One antigen binding site appeared to be exposed on the LPS of both organisms, while one epitope was exposed on the LPS of E. coli 0157 only, and another on the LPS of Y. enterocolitica 09 only.

One hundred and twenty-eight shigella strains isolated from newborn and infant human faecal specimens at Kaohsiung Medical College Hospital in Taiwan were serogrouped, serotyped and examined for drug-resistance patterns and for the presence of plasmids. Forty-seven pre cent of the isolates were found to belong to the Shigella sonnei serogroup, 41%to the S.flexneri group,9%to the S.boydii group and 3%to the S.dysenteriae group.The serotype with the greatest number of strains was S.sonnei I. (29 %) followed by S. flexneri 1 (27%). Each strain was tested for resistance to 11 antimicrobial agents. Eighty-eight per cent of the strains were resistant to tetracycline, 87% to chloramphenicol, 84% to streptomycin, 52% to ampicillin, 25% to nalidixic acid, 29% to kanamycin, 11 % to cephalothin, 11% to neomycin, 10% to cotrimoxazole, 1% to amikacin and none to gentamicin. The most prevalent resistance pattern was ApCmSmTc (28%). Clinical isolates demonstrating multiple resistance were found to harbour a large transmissible plasmid of 45–75 MDa while isolates without multiple resistance did not. Two large virulence plasmids of 123 and 110 MDa were found in 12 strains of S. flexneri and 4 strains of S. sonnei phase I. Small plasmids of 4·5, 4·2, 3·5, 2·8, 2·5. 2·0 and 1·5 MDa were also present in all strains. These small plasmids were species specific and can be used as marker plasmids to identify species.

Serum samples collected from individuals of a wide range of ages in South Yorkshire between 1969 and 1990 provided the basis for a longitudinal seroprevalence survey of Toxoplasma gondii antibodies. Sera numbering 3868 were screened for T. gondii specific antibodies using a commercial latex agglutination test. The resultant temporal series of serological profiles revealed a rise, with age, in seroprevalence, the rate of which showed a decrease through time. A plateau of around 40–50% prevalence was attained by the 41- to 45-year age-class in 1969 which was not approached until the 66- to 70-year class in the 1988–90 data set. This trend for decline in seroprevalence was confirmed by statistical analysis for the age range 21–60 years. These results may be indicative of a decrease in the rate of toxoplasma exposure in this study community over the 20-year period. The survey of 1988–90 provides a base-line profile of present-day seroprevalence in which 11 % of individuals in the age range 16–45 years (roughly corresponding to the childbearing age-range) show evidence of past infection. The representative nature of the serum collection and public-health implications of these results are discussed.

Oesophagus samples from 714 cattle from Western Australia were examined by artificial digestion to detect the presence of Sarcocystis spp. The overall prevalence of infection was 52%. The prevalence of infection increased with age and was highest in the entire males (92%). The prevalence was lower in cattle which originated from arid and semiarid regions (9 and 31% respectively) than those from tropical (87%) and temperate (60%) regions. possible reasons for these differences are discussed and it is concluded that environmental and management factors as well as host age and sex influence the prevalence of infection with Sarcocystis spp. in cattle.

The inner membrane of the air cell of hens' eggs was inoculated with Pseudomonas putida, Staphylococcus xylosus, Enterococcus faecalis, Escherichia coli and Salmonella enteitidis.The first mentioned eventually dominated the contamination of the albumen of eggs stored at 4, 15, and 20 °C. The last mentioned did so in eggs stored at 37 °C. The interval between inoculation of the membrane and gross contamination of the albumen was markedly influenced by site of contamination relative to yolk movement.

Unwoven cloth coated with 32 mg/g of a copolymer of N-benzyl-4-vinyl-pyridinium chloride and styrene was found to be effective in removing micro-organisms from water. In experiments demonstrating removal of Escherichia coli by filtration through ten sheets of the unwoven cloth, the rate of removal was 99·99% at a filtration rate of 2·6 cm/h, and remained at 99% even at a high filtration rate of 300 cm/h and a low influent concentration of the bacterial cells such as 10 cells/ml. The rate of removal tended to increase with a decrease in the influent bacterial concentration. Seven other bacteria and two yeasts were effectively removed by filtration through the unwoven cloth. Filtration through the unwoven cloth was also effective in removing spores of fungi from water but was not very effective in removing bacteriophage T4 from aqueous solution.

Enzyme-linked immunoabsorbent assay (ELISA) was used to titrate virus-specific IgG, IgM and IgA levels in nasal secretions, lung lavage fluids and serum samples sequentially obtained from lambs experimentally infected with bovine respiratory syncytial virus (RSV). Virus-specific IgG and IgM responses were measured by the indirect double antibody sandwich ELISA using anti-bovine RSV monoclonal antibody, as capture antibody, and peroxidase-conjugated anti-sheep IgG and anti-sheep IgM. Virus-specific IgA antibodies were measured by antibody capture assay using anti-sheep IgA (α–chain specific) and anti-bovine RSV monoclonal antibodies.

Bovine RSV-specific IgM and IgA antibodies were detected in the serum samples within 6 days post-inoculation (p.i.). Virus-specific IgC antibodies appeared in serum samples 4 days later. In nasal secretions, IgA antibodies appeared 7 days p.i. but IgM antibodies were not detected until 12–16 days p.i. In serum samples, IgM titres were predominant for the first 2 weeks p.i. IgC titres becoming predominant thereafter. In nasal secretions and lung lavage fluids, IgA titres were significantly higher than IgM or IgG titres up to 21 days p.i. (0·01).

The epidemiological, clinical and virological features of 1220 children with acute bronchiolitis admitted to the Prince of Wales Hospital, Hong Kong, from 1985 to 1988 are reported. They accounted for 6·6% of total paediatric admissions and provided a case incidence of bronchiolitis requiring admission to hospital of approximately 21 per 1000 children 0–24 months of age.

The clinical course and outcome was in general benign. The average hospital stay was 5 days and there were no deaths. Ten per cent of patients were repeatedly admitted to hospital with recurrent wheezing after discharge. Two infants developed bronchiolitis obliterans.

Respiratory syncytial virus (RSV) was shown by direct immunofluorescence, virus culture and serology to be the commonest cause of acute bronchiolitis in Hong Kong. Other aetiological agents included parainfluenza and influenza viruses, adenoviruses, and Mycoplasma pneumoniae.

In contrast to western countries, a seasonal variation of bronchiolitis was found with a peak incidence in the summer months. The significance of these observations is discussed.

We studied, for two years, the prevalence of indigenous human enteric viruses in wild oysters gathered each month from the bottom of Mikawa Bay, Aichi Prefecture, Japan. Viruses were detected periodically in 9 out of 54 oyster pools prepared by the acid or polyethylene glycol precipitation method although all these 9 pools met current national bacteriological safety standards. Since most of the serotypes of the enteric viruses detected in the oysters were identical with those of viruses isolated from sick children living in the area, it is suggested that contamination of enteric viruses in the oysters would depend on the prevalence of enteric viral infections in the local inhabitants.

Antibody-capture enzyme-linked immunosorbent assays (AC-ELISA) which use enzyme-labelled antigen were developed for detection of varicella-zoster virus-(VZV) specific IgM, IgA and IgG antibody in patients with varicella or herpes zoster and in sera from healthy individuals. All 18 patients with varicella developed a VZV-IgM and a VZV-IgG response, 17 also a VZV-IgA response. In contrast, all 19 patients with herpes zoster were shown to be positive for VZV-IgA whereas only 13 of these reacted positively for VZV-IgM. A VZV-IgM response was detected in only two sera from 100 healthy individuals and an IgA response in only one. The presence of virus-specific IgA and IgG in the cerebrospinal fluid as determined by AC-ELISA was a useful indicator of VZV infection of the central nervous system.

By AC-ELISA, VZV-IgG was detected predominantly in sera from patients with acute or recent VZV infection. Only 14 sera from 100 healthy individuals were positive for VZV-IgG by AC-ELISA, whereas all were positive by an indirect ELISA. These results indicate that AC-ELISA's may be useful assays for determination for acute or recurrent VZV infection, but are not suitable for determination of past infection with this virus.

A synthetic oligodeoxynucletide of 40 nucleotides corresponding to nucleotides 33–72 of the gene coding for the viral protein VP7 of rotavirus, was used as a nucleic acid probe to develop a non-radiactive hybridization method for rotavirus detection. The probe was labelled at the 3' end with biotin-7-dATP. The sensitivity and specificity of the dot blot hybridization assay for rotavirus detection was evaluated with 303 stool specimens. The results indicate that the hybridization assay has a higher sensitivity than both PAGE and EIA. Among the rotavirus strains tested 37 different electropherotypes were found. The results suggest that rotavirus diagnosis by dot hybridization using a non-radioactive probe may become routine laboratory procedure because it is simple, highly specific and very sensitive.

Summary An hypothesis that there was an annual emergence of Rift Valley fever virus in Zambia, during or after the seasonal rains, was examined with the aid of sentinel cattle. Serum samples taken during 1974 and 1978 showed evidence of epizootic Rift Valley fever in Zambia, with more than 80% positive. A sentinel herd exposed from 1982 to 1986 showed that some Rift Valley fever occurred each year. This was usually at a low level, with 3–8% of the susceptible cattle seroconverting. In 1985–6 more than 20% of the animals seroconverted, and this greater activity was associated with vegetational changes - which could be detected by remote-sensing satellite imagery-which have also been associated with greater virus activity in Kenya.

Four ponies were each inoculated with a different serotype of African horse sickness virus (AHSV) which had been passaged through cell culture in order to achieve attenuation. Three of the ponies died suddenly after showing mild clinical signs, the fourth pony remained clinically normal and was killed at day 38. Infectious AHSV was isolated from blood samples collected at intervals from all four ponies. Positive antigen ELISA reactions were only observed with blood samples from two of the ponies on the two days preceding death. Specific AHSV antibodies were detected by ELISA in serum samples from the other two ponies although one eventually died. African horse sickness viral antigens were detected by ELISA in post-mortem tissue samples collected from all four ponies. No infectious virus could be detected in tissue samples taken post-mortem from the pony which survived African horse sickness (AHS) infection. In the event of a suspected outbreak of AHS it is recommended that sera and heparinized blood should be tested for specific antibodies and AHSV antigen respectively. When available, post-mortem tissues, including spleen, heart, lung and liver, should also be tested for AHSV antigen. Although the ELISA used for the detection of AHSV antigen is highly sensitive and specific, negative ELISA results should be confirmed by virus isolation attempts.