During the autumn of 1992, Western Australia experienced a large viral meningitis outbreak of dual aetiology. Of the 161 cases, 64% were children under 15 years of age, with the highest notification rate being in children less than 5 years of age. Echovirus 9 caused 41% of cases and occurred mainly in the metropolitan areas of Western Australia whereas echovirus 6, which caused 37% of cases, was more widespread. An enterovirus was cultured from 70% of CSF specimens, 88% of faecal specimens and 68% of upper respiratory tract specimens. High CSF white cell counts and neutrophil predominance were common. Seven cases had normal CSF white cell counts even though an enterovirus was isolated from the CSF. Therefore, the CSF findings were of restricted value in excluding viral meningitis, and did not reliably distinguish between bacterial and viral meningitis.

The seroprevalence of human T-lymphotropic virus type I (HTLV-I), in relation to that of human immunodeficiency virus type 1 (HIV-1), was determined in a comparative unlinked anonymous antenatal and neonatal (for indirect measurement of maternal antibodies) serosurvey in the Gauteng region of South Africa, using dried blood spots (DBS) and modified particle agglutination assays. Samples were confirmed to be antibody positive by western blot. A total of 2582 DBS collected during 1993 and 1994 from subjects of African, European and coloured origin were tested. Ten were confirmed as positive for HTLV-I and 128 for HIV-1. No antibodies to HTLV-I or HIV-l were demonstrated in the 221 women of European and coloured origin who were screened. The HTLV-I seroprevalence rate in subjects of African origin appeared to increase from 0% in 1993 to 0·49% in 1994, while HIV-1 seroprevalence rates of 5·2% and 5·4% were recorded for 1993 and 1994 respectively. No significant differences in HTLV-I and HIV-1 seroprevalence rates were noted for the two areas investigated. These results indicate that HTLV-I should be included in infection control programs, and provide baseline data for monitoring the possible spread of HTLV-I in the heterosexual population in this region.

To determine whether recently diagnosed adult–onset asthma is associated with serologic evidence of chronic Chlamydia pneumoniae infection, we performed a case-control study in a primary care clinic of cases with asthma (25 adults reporting first symptoms of asthma within 2 years of enrollment) and 45 concurrently enrolled sex and age (±10 years) matched non-asthmatic controls with normal pulmonary function. C. pneumoniae-specific IgA, IgG and IgG4 antibodies, and circulating immune complexes (CIC) were measured by microimmunofluorescence testing. Results showed that frequencies of IgG litres > 16 (92%), IgG4 litres > 16 (20%) and CIC > 4 (60%) in asthma patients were not significantly different from those of controls. However, asthmatics had a significantly higher prevalence of C. pneumoniae-specific IgA litres > 10 (72% of cases vs 44% of controls, P < 0·05). After adjustment for the effects of age, sex and smoking, the odds ratio for an association of IgA and asthma was 3·7 (95% confidence interval 1·2–11·5). We conclude that recently symptomalic reversible airway obstruction in adults is associated with the presence of C. pneumoniae-specific IgA antibodies, a proposed indicator of chronic respiratory C. pneumoniae infection.

Isotype-specific antibody responses to foot-and-mouth disease virus (FMDV) were measured in the sera and upper respiratory tract secretions of vaccinated and susceptible cattle challenged with FMDV by direct contact or by intranasal inoculation. A comparison was made between cattle that eliminated FMDV and those that developed and maintained a persistent infection. Serological and mucosal antibody responses were detected in all animals after challenge. IgA and 1gM were detected before the development of IgG1 and IgG2 responses. 1gM was not detected in vaccinated cattle. Challenge with FMDV elicited a prolonged biphasic secretory antibody response in FMDV ‘carrier’ animals only. The response was detected as FMDVspecific IgA in both mucosal secretions and serum samples, which gained statistical significance (P < 0·05) by 5 weeks after challenge. This observation could represent the basis of a test to differentiate vaccinated and/or recovered convalescent cattle from FMDV ‘carriers’.

We describe an outbreak of skin lesions due to Mycobacterium chelonae subsp. abscessus associated with injections of lidocaine (lignocaine) given by a ‘bioenergetic’ (a practitioner of alternative medicine) in Colombia. The lidocaine carpules and the lesions of the patients yielded mycobacteria with identical biochemical characteristics.

Using the methodology of Sartwell and a case control design we examined the incubation period and assessed risk factors. Of 667 potentially exposed individuals, a total of 298 patients were interviewed, of whom 232 had skin lesions. The median incubation period was 30·5 days (range 15–59 days). Male sex (OR 2·85, 95% CI 1·26–6·51), increasing age (OR 1·25, 95% CI 1·03–1·53), subcutaneous injection route (OR 3·72, 95% CI 1·09–12·7) and number of injections (OR 1·01, 95% CI 1·00–1·03) were risk factors for disease.

To our knowledge, this is the largest reported outbreak of M. chelonae infection, the first in which the organism has been isolated from the putative vehicle of infection, and the first in which the incubation period could be determined.

The costs and projected benefits of universal screening for hepatitis B virus (HBV) infection in pregnant women in East Anglia are calculated and compared with current practice. By adjusting data from West Midlands region for ethnicity, the prevalence of maternal hepatitis B surface-antigen (HBsAg) positivity in East Anglia is predicted to be 0·083% (1 in 1200). Published data on health risks of perinatal HBV infection and on immunisation efficacy are used to derive benefits of screening. The marginal direct cost of screening is identified from regional sources. Current clinical practice in East Anglia identifies 7 surface-antigen positive mothers per year, whereas 22 are expected. Routine antenatal screening in East Anglia would prevent 2·6 additional childhood carriers per year (compared with current practice), resulting in the prevention of 0·7 deaths per year occuring 40–50 years in the future. The direct cost per (undiscounted) life-year saved would be £2437, not including savings on treatment for chronic hepatitis B infection. Routine prenatal screening for maternal HBsAg should be introduced without delay and continue even if HBV vaccination is introduced into the UK childhood immunisation schedule.

Maternal, cord and infant measles antibody levels were measured and compared in a group of 411 vaccinated mothers and 240 unvaccinated mothers, and their babies, between 1983 and 1991. Maternal and cord sera were tested by haemagglutination inhibition and/or enzyme-linked immunosorbent assay, and plaque reduction neutralization tests were also used to test infant sera. Geometric mean litres were significantly higher in the unvaccinated than in the vaccinated mothers (P < 0·001). Infants born to mothers with a history of measles had higher antibody levels at birth than infants of vaccinated mothers and, although the difference narrowed over time, continued to have higher levels up to 30 weeks of age. Between 5 and 7 months of age significantly more of the children of vaccinated mothers had plaque reduction neutralization antibody levels below that which would interfere with vaccination. As the boosting effect of circulating natural measles disappears, earlier measles vaccination may need to be considered, perhaps as part of a two-dose policy.

A survey of evidence of rodent hantavirus infection in County Down, Northern Ireland was carried out by using immunofluorescence to detect virus antigen and antibody. Antibodies to hantavirus (R22 strain of Seoul virus and Hantaan 76–118) were found in 11/51 (21·6%) brown rats (Rattus norvegicus), 1/31 (3·2%) field mice (Apodemus sylvaticus) and 17/59 (28·8%) house mice (Mus domesticus). Seven rodents had evidence of hantavirus antigen in lung tissues. Antibody positive animals were significantly more likely to be adults than juveniles (P = 0·04) but and there was no sex difference between antibody positive and negative animals. House mice were more likely to be antibody positive if captured inside farm outbuildings (P = 0·08). Attempts to culture virus from the rodent material were unsuccessful. This work demonstrates a substantial rodent reservoir for hantavirus in Northern Ireland.

To describe the features of hepatitis B virus (HBV) infection in Madagascar, a randomized sero-epidemiological survey was undertaken in the general population ≥ 1 year old of two provinces which represents 45% of the total population. In the 921 sera tested, the prevalence of HBV markers was 20·5% for HBsAg, 38·2% for anti-HBc and 6·9% for HBeAg. HBsAg and anti-HBc prevalence rates were significantly higher in males. A large difference in HBsAg prevalence was observed between urban (5·3%) and rural areas (26·0%). The same contrast in prevalence was noticed for the other HBV markers. In rural areas, HBV infection was more frequently acquired early in infancy, which suggests predominantly perinatal or postnatal transmission. The presence of HBV markers was not significantly associated with a history of blood transfusion, surgery or parenteral injection. High infectivity carriers represented 5·3% and the overall frequency of chronic carriers was 10·4%. These results place Madagascar among areas of high endemicity.

Community studies in Guinea-Bissau have found that exposure to measles prior to 6 months of age is associated with delayed mortality later in childhood. In an attempt to understand the underlying mechanism, we examined the role of pre-exposure nutritional status and the impact of exposure to measles on growth and subsequent mortality in these outbreaks. Though exposed children were lighter than controls, there was no association between pre-exposure weight-for-age and subsequent mortality adjusting for age. Although exposure was strongly associated with excess mortality, it did not have a negative impact on growth. Adjustment for state of nutrition did not alter the mortality ratio (MR) between 6 and 59 months of age for exposed children and controls; exposed children examined anthropometrically between 6–17 months had a MR of 3·70 compared with controls. This trend was the same for anthropometric measurements obtained at 18–59 months of age. Among the controls, there was a significant association between weight-for-age and subsequent mortality to the age of 5 years. However, for exposed children there was no association; the relation between weight-for-age and subsequent mortality was significantly different for exposed children compared with controls (tests for interaction between exposure and anthropometric measurements at 6–17 months: P = 0·05). Growth faltering as a consequence of early exposure to measles does not explain the marked excess mortality among these children. Further studies of the process underlying delayed mortality after early exposure to measles are warranted.

A detailed analysis of equine (H3N8) influenza viruses isolated in Nigeria during early 1991 has been undertaken. Antigenic analysis and the complete nucleotide sequence of the HA gene of three Nigerian equine influenza viruses A/eq/Ibadan/4/91, A/eq/Ibadan/6/91 and A/eq/Ibadan/9/91 are presented and limited sequence analysis of each of the genes encoding the internal polypeptides of the virus has been carried out. These results establish that, despite the geographical location from which these viruses were isolated, two were similar to the viruses which were concurrently causing disease in Europe in 1989 and 1991 and were related to viruses that have been predominating in horses since 1985. The third was more closely related to viruses isolated from 1991 onward in Europe but also in other parts of the globe. A comparison of the nucleotide sequence of two of the viruses isolated in Nigeria (A/eq/Ibadan/4/91 and A/eq/Ibadan/6/91) with a European strain (A/eq/Suffolk/89) showed limited variation in the haemagglutinin gene which caused amino acid substitutions in one of the antigenic sites: this mutation resulted in the potential production of a new glycosylation site in antigenic site A. The other Nigerian virus (A/eq/Ibadan/9/91) showed only a single one amino acid change from another European strain (A/eq/Arundel/12369/91). The two distinct Nigerian viruses had several amino acid substitutions in the antigenic sites of the haemagglutinin glycoprotein.

A case control study of foal diarrhoea in the United Kingdom was carried out over a 3-year period. Clostridium perfringens was significantly associated with foal diarrhoea (Odds Ratio (OR) = 3·0), being isolated from 57% of 421 animals with diarrhoea but from only 27% of 223 healthy foals. Also, C. perfringens was significantly associated with fatal diarrhoea (OR = 4·5). About half of diarrhoea with a fatal outcome was attributable to this organism.

The other pathogens significantly associated with diarrhoea were rotavirus (OR = 5·6), Cryptosporidium spp. (OR = 3·2) and the nematode Strongyloides westeri, which was significant only when present in large numbers (> 2000 eggs/g of faeces: OR = 6·1). Salmonella spp. (OR = 14·2) and Cryptosporidium spp. (OR = 3·0) were the only other pathogens associated with fatal illness.

Overall, C. perfringens, rotavirus, and large numbers of Cryptosporidium spp. or S. westeri were isolated from 80% of foals with diarrhoea. Thermophilic Campylobacter spp., Yersinia enterocolitica, Escherichia coli and other parasites were not associated with diarrhoea. Carriage of C. perfringens, rotavirus and Cryptosporidium spp. was significantly greater in healthy foals in contact with cases of diarrhoea than in foals that were not in contact with diarrhoea (P < 0·05). There were no statistical interactions between any of the pathogens associated with diarrhoea although separate cases from one location often involved more than one pathogen.

The genotype of HCV was determined in 161 chronic HCV-infected patients. The patients were classified into three groups on the basis of the origin of the HCV infection: 50 patients had a history of intravenous drug use (IVDU) but no HIV infection; 41 patients had received blood transfusions, and 70 patients had no known exposure. The distribution of HCV genotypes was associated with the origin of infection and age of patients: genotype 1b was predominant among patients who had received blood transfusions and those without evidence of parenteral exposure (84·6% and 67·7%, respectively), whereas genotype 3a was present in 65·3% of IVDUs. Patients with genotype 1b were older than those with genotypes la or 3a: 50·3 ± 12 vs. 34·1±9·9 and 31 ± 5.4 years, respectively. These findings suggest that the pattern of HCV genotypes in our region is changing and that genotype 1b may be substituted by 3a as the dominant genotype in the future.

We undertook a retrospective descriptive comparison of the spectrum of pathogens responsible for bacteraemia and diarrhoea in HIV antibody positive and negative patients over 4 years (1988–92), in Nairobi, Kenya. The study population was recruited from primary to tertiary centers of clinical care and consisted of 2858 adults (15 years or older). There were 415 significant blood culture isolates, 192 from 1785 HIV negative patients and 223 from 953 HIV positive patients. There were 233 significant faecal isolates, 22 from 115 HIV negative patients and 211 from 531 HIV positive patients. The most common pathogens detected in blood were Streptococcus pneumoniae and Salmonella typhimurium and in faeces Shigella flexneri, S. typhimurium and Cryptosporidium parvum. The agents causing illness in HIV positive patients in Nairobi are similar to those prevalent in the HIV negative community and the investigation of a febrile illness with or wothout diarrhoea in an HIV positive patient should reflect this.

A total of 32 Vibrio ordalii strains were studied for their plasmid content and shown to carry a plasmid of approximately 32 kb. This plasmid was subsequently subjected to restriction fragment length polymorphism (RFLP) studies. Using Hind III, three different restriction patterns were identified while BamHI cleaved the plasmid into a single linear fragment. The results suggest that the 32 kb plasmid is highly conserved but that some variation in restriction pattern occurs. The same set of strains was subjected to ribotyping. Using Mlu I, six different restriction patterns were demonstrated. Strains from the USA and Canada shared profiles with strains from Australia and Japan. Strains from Australia generated a single pattern whereas strains from North America were subdivided into three patterns, and the Japanese strains fell into five patterns. The results suggest that ribotyping in combination with RFLP studies of the pMJ101-like plasmid may be useful in epidemiological studies of V. ordalii.

Progress in the development of schistosomiasis models for use in control programmes is limited by the considerable uncertainty in many of the biological parameters. In this paper, this problem is addressed by a comprehensive sensitivity analysis of a schistosomiasis model using the Latin Hypercube method. Fifty simulations with different parameter contributions are run for 50 years with treatment during the first 20 years and reinfection thereafter. The analysis shows only a relatively small divergence between simulations during the chemotherapy treatment programme but considerable divergence in reinfection levels after treatment is stopped. A skewed distribution of outcomes was seen with most simulations showing effective control and a few where control had less impact. The most important uncertainty source was due to the unknown levels of acquired immunity and also uncertainty in the true worm burden. In particular, the strength of the immune response was most important in determining whether control was effective with higher immunity leading to less effective control. Among those simulations in which control was not very effective, those in which the mean worm burden was high showed the least effective control. Since both these are areas of genuine uncertainty, it is proposed that uncertainty analysis should be an integral part of any projection of control programmes.

The purpose of this study was to examine the prevalence of antibody against hepatitis A (anti-HAV) in a population of homosexual men compared with that of heterosexual men in an area of intermediate HAV endemicity (Madrid, Spain). A total of 148 patients were recruited in a Sexually Transmitted Diseases Clinic: 74 homosexuals (mean age of 28±5 years) and 74 heterosexuals (29±5 years). The prevalence of anti-HAV antibody was 47% and 43% for homo-and heterosexuals, respectively. Among the factors evaluated (age, sexual orientation and practices, travel to high HAV endemicity areas) oral-anal contact was significantly associated with a higher prevalence of anti-HAV antibody (odds ratio, 2·8; 95% confidence interval, 1·1–7·4; P = 0·03). These results indicated that in an area of intermediate endemicity young homosexual men are not at increased risk of having acquired hepatitis A infection than heterosexuals. Oral–anal contact is an independent risk factor that influences the presence of anti-HAV antibody, regardless of sexual orientation.

Multilocus enzyme electrophoresis was used to examine the relatedness of 52 isolates of Clavibacter toxicus, the agent of annual ryegrass toxicity. These included 37 Western Australian (WA) field isolates sampled in 3 distinct locations over a 2-year period, and 15 isolates sampled from 6 different host plant species in 3 states in Australia over approximately 8 years. Seventeen reference strains for the related genera Curtobacterium, Rhodococcus and Arthrobacter were examined for comparison. The 69 isolates were divided into 29 electrophoretic types (ETs), separated by genetic distances of 0·06 to 0·81. The C. toxicus isolates fell into 12 ETs, 11 of which formed a tightly clustered group separated by a genetic distance of 0·23 or less. Thirty-one of the WA field isolates of C. toxicus fell into a single ET, and four into another ET. Clavibacter toxicus therefore formed a closely related group which was genetically distinct from the other plant pathogenic species, and a dominant widely disseminated strain of the species was identified in WA.

Hospital discharge data from 1990–4 for 26 hospitals were used to estimate and compare the cost and describe the epidemiology of severe giardiasis and cryptosporidiosis in Scotland, UK. The incidence of severe cryptosporidiosis was almost double that of severe giardiasis and the median duration of hospitalization was longer for cryptosporidiosis than giardiasis. Impaired immunity was frequently listed as co-diagnosis with cryptosporidiosis and associated with extended hospitalization. Although both infections were associated with infants, the median age was lower for cryptosporidiosis (5 years compared with 30 years). Whereas hospitalization was not significantly longer for infants with cryptosporidiosis, hospitalization for this age group with giardiasis was longer (4 days compared with 3 days). Comparison with similar data for giardiasis from USA revealed various differences and similarities. These points are discussed in relation to the epidemiology of these infections and published data were used to estimate costs of hospitalization.

An epidemiologic investigation was conducted to characterize and evaluate the possibility of a viral aetiology of an outbreak of acute vertigo in Hot Springs Country, Wyoming, during autumn 1992. Case-finding identified Hot Springs County residents who sought medical attention for new onset vertigo during 1 August, 1992–31 January 1993. Thirty-five case-patients and 61 matched controls were interviewed and serum specimens were obtained during January 1993. Case-patients were more likely than controls to report symptoms (e.g. fatigue, sore throat, fever, diarrhoea) of antecedent acute illness. Case-patients did not have a significantly greater prevalence or mean titre of IgG antibodies to respiratory syncytial virus, parainfluenza viruses, Epstein–Barr virus, and cytomegalovirus than controls. Serologic evidence of recent enterovirus infection (IgM antibodies) was found for 74% of case-patients compared with 54% of controls (P < 0·05), suggesting a possible association between vertigo and enterovirus infection. Future studies are needed to define the role of enteroviruses in inner-ear diseases.