From 1979 to August 1987, there have been 178 cases of meningococcal disease in Iquique, Chile, a city of about 140000. The attack rate for the last 5 years has been in excess of 20/100000 per year, more than 20 times greater than for the country overall. The mortality rate was 6%. The disease occurred in patients with ages from 4 months to 60 years, but 89% of cases were in patients <21 years. The largest number of cases were in the age group 5–9 years (n = 54), but the highest incidence occurred in children less than 1 year of age (72·8/100000 per year). The male/female ratio was 1·2. Cases occurred all year round with little seasonal variation. Of the 178 cases, 173 were biologically confirmed. Serogroup analysis of strains from 135 patients revealed A = 1, B = 124, C = 10. Forty-four group B strains from 1985–7 were serotyped: 15:P1.3 = 36, 15:NT = 4, 4:P1.3 = 2, NT:NT = 2. Ten of 11 of the outbreak strains tested were sulfadiazine-resistant. This is the first recognized outbreak caused by a Gp B:15 strain in South America. It shares many of the characteristics of outbreaks caused by closely related strains in Europe, such as a predilection for older children and adolescents, sulfadiazine-resistance, and sustained high attack rates. The Iquique strain (B:15:P1.3) belongs to the same genetic clone (ET-5 complex) as the Norway (B:15:P1.16) and the Cuban (B:4:P1.15) strains.

Most villagers in north-east Thailand carry water to their homes and store it in separate containers depending on its subsequent use. In one village, information on water use was collated with the bacteriological quality of stored water, water sources and fingertip-rinses. Stored water quality was a function of water-related activities rather than quality at source (P<0·0001). Specifically water used for toilet, washing dishes and cooking-related activities was much more contaminated with faecal bacteria than that used for drinking and cooking. Salmonella spp. was significantly more common in water used for washing dishes than drinking (P<0·05). Escherichia coli contamination of fingertip-rinses was strongly associated with the individual's activity prior to testing (P<0·0001); child care, food and water-related activities produced much higher levels of fingertip contamination than others. Dirty utensils used for cooking and eating were usually left to soak and faecal bacterial growth occurred in this grossly contaminated soak-water. Cross-contamination via water handling was the main mechanism of stored water pollution. These results were used to develop a hygiene intervention study presented in a companion paper.

An intervention study was developed from risk-factors associated with faecooral transmission, based on the levels of contamination in stored water and fingertip-rinses from households in rural north-east Thailand. This was designed to improve: (a) handwashing, particularly before cooking/eating and after defecation; (b) washing dishes immediately after use. Verbal messages were administered to two intervention groups, one also received a plastic container with a tap to assist these activities. Indicators of compliance were the direct observation of soaking dishes and the presence of faecal streptococci from fingertip-rinses; the main outcome indicator was Escherichia coli contamination of stored water. The intervention group receiving the container was significantly better than the control for indicators of compliance (P < 0·001 and P < 0·01) and its stored water was significantly less contaminated (P < 0·001). There was no significant improvement to the other intervention group, although some features of the intervention had clearly been made available to the control group. Humidity was significantly correlated with fingertip contamination (r = 0·2; P < 0·001) and with the peak of reported diarrhoea around the beginning of the rainy season.

Forty-two cultures of pseudomonas comprising 28 clinical isolates from a pseudo-outbreak on a Special-Care Baby Unit and 14 reference strains, including 9 type strains, of various Pseudomonas species, were characterized by one-dimensional sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE) of whole-cell proteins. The protein patterns were highly reproducible and were used as the basis for a numerical analysis which divided the strains into 9 phenons. Two of the 28 clinical isolates were identified by biochemical tests as P. pickettii and their identification was confirmed by SDS–PAGE as they fell in the same phenon as the type strain of the species. The remaining 26 isolates, which could not be identified on phenotypic tests, fell in the same phenon as three reference strains of ‘P. thomasii’. The protein patterns provided the first clear evidence that P. pickettii and ‘P. thomasii’ were separate taxa and that the ‘outbreak’ was polymicrobial in origin, in line with the probable aqueous source of contamination. We conclude that high-resolution SDS–PAGE of proteins provides an effective method of identifying and differentiating pseudomonads, especially where this cannot be done adequately using conventional biochemical tests.

A high attack rate (17·3/100 000) of meningococcal disease in army recruits in Italy, with 95% of the cases due to serogroup C, constituted the motivating factors to make bivalent serogroup A + C meningococcal vaccination compulsory by law for army recruits starting January 1987. Because the vaccine was given only to the new recruits entering the army, full coverage was not achieved until January 1988. Nearly 900 000 subjects (300 000 yearly) were vaccinated between January 1987 and December 1989. There were no reports of any untoward reactions to the vaccine. Of the 300 000 recruits in service each year, 52, 21, 15, 5 and 4 cases of the disease occurred in 1985, 1986, 1987, 1988 and 1989, respectively (P < 0·001).

Of the 24 cases occurring since the start of the vaccination, only two (due to serogroup C) were attributable to vaccine failure. The remaining cases were in unvaccinated recruits (15 cases) or were due to serogroups other than A or C (7 cases). The cumulative incidence of meningococcal serogroup C in the 600 000 vaccinated recruits during the period 1988–89 was 0·2/100 000 (1 case amongst 600 000 recruits), while the corresponding figure in the 600 000 unvaccinatred recruits during the period 1985–6 was 11·3/100000 (68 cases amongst 600 000 recruits) (P < 0·001). The protective efficacy of the vaccine in 1987 was 91·2% (12 cases of meningococcal serogroup A and C disease from an average of 150 000 unvaccinated recruits observed for 1 year, and 1 case from the corresponding average of 150 000 vaccinated ones). In 1988 and in 1989 this figure could not be calculated because all recruits were vaccinated.

The incidence of meningitis caused by other serogroups of meningococci remained low, both before and after the mass vaccination campaign.

Prospective epidemiological studies of beach water pollution were conducted in Hong Kong in the summers of 1986 and 1987. For the main study in 1987, a total of 18741 usable responses were obtained from beachgoers on nine beaches at weekends. The study indicated the overall perceived symptom rates for gastrointestinal, ear, eye, skin, respiratory, fever and total illness were significantly higher for swimmers than non-swimmers; and the swimming-associated symptom rates for gastrointestinal, skin, respiratory and total illness were higher at ‘barely acceptable’ beaches than at ‘relatively unpolluted’ ones. Escherichia coli was found to be the best indicator of the health effects associated with swimming in the beaches of Hong Kong. It showed the highest correlation with combined swimming-associated gastroenteritis and skin symptom rates when compared with other microbial indicators. A linear relationship between E. coli and the combined symptom rates was established. Staphylococci were correlated with ear, respiratory and total illness, but could not be used for predicting swimming-associated health risks. They should be used to complement E. coli. The setting of health-related bathing-water quality standards based on such a study is discussed.

Between 1972 and 1988 we have serologically confirmed 103 Coxiella burnetii infections: 46 were acute, 5 were chronic, 52 represented past infections. Details of 61 cases are presented.

Of acute cases 80 % had respiratory involvement; at least 63 % had pneumonias. The incidence (22%) of neurological complications was of particular interest; 40% of these patients had prolonged sequelae. One acutely ill patient died of fulminating hepatitis. Patients with pre-existing pathology or immunosuppression were especially susceptible to C. burnetii.

In the absence of acute sera, the complement fixation test alone provided inadequate differentiation between recent and past Q fever: phase II titres persisted at ⋝ 80 for more than 1 year after the acute infection in 15 cases; maximum duration of persistence was 14 years. Three patients acquired high phase I titres.

Only 5% of cases had chronic Q fever, but in view of the diverse sequelae observed in this series, we suggest that long-term serological and clinical follow-up of all cases of Q fever is fully justified.

A total of 535 sera from eight species of wildlife were collected from different game areas in Tanzania between 1987 and 1989. These sera were tested for antibodies against foot-and-mouth disease, bovine herpes virus types 1 and 2, lumpy skin disease, bovine viral diarrhoea, Akabane, bovine ephemeral fever, bluetongue, enzootic bovine leucosis, African horse sickness and African swine fever viruses and Brucella abortus based on the expected species susceptibility. Sera from buffalo Syncerus caffer, wildebeest Connochaetes taurinus and topi Damaliscus korrigum contained antibodies against the majority of the pathogens tested. Antibodies to fewer pathogens were detected in sera from the other species. No antibodies to lumpy skin disease virus were detected in any of the sera examined. African horse sickness antibodies were detected in sera from Zebra and African swine fever antibodies were detected in wart hog. The occurrence of antibodies to these agents suggests that wild species act as reservoirs of infection for some of these pathogens. However, until the susceptibility of individual species is proven by isolation of the aetiological agents their role must remain speculative.

Recent publicity concerning congenital toxoplasmosis has generated a demand for serological assessment of pregnant women. Many laboratories are requested to undertake primary screening in these cases. We assessed the latex agglutination test (LAT) findings in 158 specimens with detectable toxoplasma specific IgM derived from pregnant women. The LAT titres ranged from 16 to ≥ 4000 reflecting the variable antibody response observed in acute toxoplasmosis. We recommend that non-reference laboratories test specimens from pregnant women using the LAT at a screening dilution of 1:16 and select all reactive samples for detailed investigation.

The objectives of this study were to determine the prevalence of scabies in an infested village; to educate the residents on self-treatment and prevention by the use of 5 % monosulfiram soap; to evaluate the short term effectiveness of this intervention by determining, 2 weeks later, the compliance to self-treatment and prevention; and to determine the prevalence rate on the second visit. In 59 households (96·7% of the village) containing 313 persons, an educational session was held and a leaflet distributed on the use and availability of the soap. Thirteen persons (4·2%) from eight households (13·6%) had scabies. After 2 weeks, 7 persons (2·2%) (2 persisting and 5 new cases) from 5 households (8·5%) were infested. Thus a cure rate of 85 % was obtained though the prevalence rate showed no statistically significant difference. Among the under 15 year olds, the numbers infected decreased from 10 to 3 while among the over 15 year olds, the numbers infected increased from 3 to 4, neither reading significance at the 5 % level.

Twenty progesterone-treated TO mice were infected intravaginally with Mycoplasma pulmonis. One month later, ten of the mice were given oestradiol which changed the reproductive cycle to the oestrous phase and within a week resulted in eradication of the organisms from six of them; vaginal persistence in the other mice may have been due, at least in part, to reinoculation of organisms from the oropharynx, a site heavily infected in all the mice. The majority of the mice not treated with oestradiol continued to shed the organisms from the vagina for at least 91 days. In another experiment, 19 oestradiol-treated BALB/c mice were infected intravaginally with M. hominis. One month later, nine of the mice were given progesterone which changed the reproductive cycle to the dioestrous phase and eradicated the organisms from seven within 2 weeks and from all of them within about a month. This was in contrast to the mice not given progesterone, the majority of which continued to shed the organisms for at least 167 days.

The Oxford panel of monoclonal antibodies was used to subtype 83 strains of Legionella pneumophila serogroup 1 of human and environmental origin. The International panel was also used to subtype 50 of them. All the 18 patients' isolates were of the Pontiac subgroup, and 40/43 of the environmental strains of the Pontiac subgroup were associated with human infection. The remaining environmental strains were subgroups Olda (15 strains), Camperdown (5 strains), and Bellingham (2 strains). The Philadelphia subgroup was the commonest among the environmental strains tested with the international MABs panel.

This study confirms previous findings that L. pneumophila serogroup 1 isolates with the Pontiac (Oxford panel) or MAB-2 (international panel) reacting antigen marker seem to be more virulent than the other subgroups.

Asymptomatic individuals seropositive for antibody to human immunodeficiency virus (HIV) were investigated for the presence of toxoplasma specific antibody. Serological examination was performed using multiple assays. Of 500 patients studied 133 had serological evidence of previous exposure to Toxoplasma gondii. Specific IgM was detected in 7 patients using ISAGA and 2 patients by DS-ELISA. The immunoglobulin-G annual seroconversion rate was calculated to be 0·75 %. The results of this study indicate 27 % of HIV positive patients in the UK are at risk of developing life-threatening secondary reactivation of cerebral toxoplasmosis in association with AIDS. A further 0·5–1 % per year may suffer primary toxoplasmosis.

Sera from 141 infants aged 0–12 months were examined for IgG antibodies to HHV-6, HSV, CMV, VZV and EBV and for HHV-6 specific IgM. Following the decline in maternal antibody, antibody to HHV-6 was found to rise by 5–6 months and approached the level found in adults by 11–12 months. In contrast the antibody rates for the other herpesviruses were much slower to rise, especially in the case of CMV and EBV. HHV-6 IgM antibodies were detected mainly in age groups showing a rapid rise in antibody to HHV-6. HHV-6-IgM was not detected in 235 cord blood samples. The data suggest that HHV-6 infection is acquired horizontally, at a very early age in Western Australia.

Occupants of 482 long-stay and 33 short-stay beds in 11 Leicester City Council homes for the elderly were studied during a 30-week period from September 1988 to March 1989 to determine the incidence, aetiology, morbidity, and mortality of acute upper respiratory tract viral infections and the use of influenza vaccine.

Influenza immunization rates by home ranged from 15·4 to 90% (mean 45%). There were no differences in the distribution of medical conditions by home. The highest immunization rates were seen in people with chest disease (77%), heart disease (60%), diabetes (56%), and those with three medical conditions (75%). There was an average of 0·7 upper respiratory episodes per bed per annum with a mortality of 3·4% (6/179). Half of all episodes were seen by a general medical practitioner and 81 of 90 (90%) referrals were prescribed antibiotics costing approximately £7.50 per patient. Lower respiratory tract complications developed during 45 (25%) of 179 episodes including 3 of 12 coronavirus infections, 3 of 9 respiratory syncytial virus infections, 2 of 4 adenovirus infections, 1 of 11 rhinovirus infections, but none of 5 influenza infections. Respiratory infections were caused mostly by pathogens other than influenza virus during the influenza period documented nationally. This highlights the role of coronaviruses, respiratory syncytial virus, and unidentified agents in the elderly, and questions the assumptions made in American estimates on the impact of influenza and the value of influenza vaccines.

In this review of 66 outbreaks of infectious disease in schools in England and Wales between 1979–88, 27 were reported from independent and 39 from maintained schools. Altogether, over 8000 children and nearly 500 adults were affected. Most of the outbreaks investigated were due to gastrointestinal infections which affected about 5000 children; respiratory infections affected a further 2000 children. Fifty-two children and seven adults were admitted to hospital and one child with measles died. Vaccination policies and use of immunoglobulin for control and prevention of outbreaks in schools have been discussed.

Serum samples from individuals of a wide age range, collected in northwest England in 1984 and 1986, provide the basis for an analysis of the epidemiology of mumps virus infection. A radial haemolysis test yielding quantitative antibody measurements was used to screen samples for mumps-specific IgG. Analyses of resultant age-seroprevalence profiles, using statistical models, revealed an age-related pattern in the rate of infection per susceptible similar to that observed for other childhood infections. This rate, or force of infection, was low in young children, high in older children, and low in adults. In addition, the serological surveys provide evidence for time-dependent changes (both epidemic and longer-term) in the rate of mumps virus transmission. The longer-term changes, reflected in the pattern of the age-acquisition of specific antibodies, are supported by evidence from case notification data. The implications of temporal changes in incidence to the interpretation and design of serological surveys are considered.

Two DNA clones were obtained from faecal specimens containing a parvovirus-like small round virus from a 1977 outbreak of gastroenteritis, and their nucleotide sequences were determined and found to be essentially identical with parts of the published sequence of serum parvovirus B19 and with a B19 isolate (JB) partially sequenced in this study. The clones corresponded mainly to genome regions coding for non-structural proteins, but also include a sequence of some 160 bp coding for structural proteins. Southern blotting experiments with a full-length B19 probe revealed a virion-sized 5·5 kbp DNA band in specimens from gastroenteritis cases in both 1977 and 1986. Thus the nucleotide sequence and hybridization results suggest that the virus seen in these studies is very similar to B19. Further work is necessary to clarify the antigenic relationship of these viruses.

After preliminary trials, the detailed changes in the concentration of specific circulating and local antibodies were followed in 15 volunteers inoculated with coronavirus 229E. Ten of them, who had significantly lower concentrations of pre-existing antibody than the rest, became infected and eight of these developed colds. A limited investigation of circulating lymphocyte populations showed some lymphocytopenia in infected volunteers. In this group, antibody concentrations started to increase 1 week after inoculation and reached a maximum about 1 week later. Thereafter antibody titres slowly declined. Although concentrations were still slightly raised 1 year later, this did not always prevent reinfection when volunteers were then challenged with the homologous virus. However, the period of virus shedding was shorter than before and none developed a cold. All of the uninfected group were infected on re-challenge although they also appeared to show some resistance to disease and in the extent of infection. These results are discussed with reference to natural infections with coronavirus and with other infections, such as rhinovirus infections.

The seasonal incidence of bluetongue virus (BTV) in Central Sudan is related primarily to fluctuations in the prevalence of the vector, Culicoides imicola. Population densities of this midge begin to rise with the onset of precipitation and peak during October, before falling sharply at the end of the rainy season in November. These are also the months of BTV transmission. Populations of C. schultzei, the commonest midge in Central Sudan, are also related to the rainy season but this species does not seem to be involved with BTV transmission.

BTV serotype 2 was isolated from C. imicola confirming the status of this midge as a known vector but a second isolate of the same serotype was made from a mixed pool of Culicoides not including C. imicola. This suggests that BTV transmission in the Sudan may involve more than one species of Culicoides. Epizootic haemorrhagic disease virus (EHDV) serotype 4 and a palyam virus were isolated from C. schultzei which indicates that this species may be involved in the transmission of BT-related viruses. Seven further virus isolates from sentinel calves at Shambat (Khartoum) confirmed the presence of BTV serotypes 1, 4 and 16, and an untyped EHDV (designated 318) in the Sudan. All of the viruses isolated and identified during the course of this work are recorded from the Sudan for the first time.