Despite rapid urbanization and increasing affluence in Karachi, cases of cholera are frequent. We analysed computerized isolation data from the AKUH Clinical Microbiology Laboratory, Karachi, from 1990–6 to examine microbiological, temporal and demographic trends in Vibrio cholerae infections. During this period 888 strains of V. cholerae (566 V. cholerae serogroup O1, and 204 V. cholerae serogroup O139) were isolated from specimens from 886 patients; 214/464 were adult inpatients, and 250/464 paediatric inpatients, the remaining 422 outpatients. Isolations peaked between June and August. Overlapping epidemics occurred in 1993 and 1994 of serogroup O1 (May to August), and serogroup O139 (August to October). All ages and social and economic strata were affected. Forty-four percent of all isolates were from children under the age of 5 years. The mean age of all patients with serogroup O1 infections was 19·6 years (±0·9) compared with 36·7 (±1·7) for serogroup O139 infections (P<0·0001, t test). More than a quarter (27%) of all serogroup O1 isolates were from babies under 2 years of age. One patient had a serogroup O1 infection followed by a serogroup O139 infection 1 year later. Another patient was infected with serogroup O1 strains 5 years apart. Emergence of resistant strains was observed, but by 1996 serogroup O139 had disappeared. An aquatic organism, cholera nevertheless continues to take its toll in this city of 11 million situated in a desert.

Plasmid profile analysis by agarose gel electrophoresis was performed on 42 drug resistant strains of Shigella boydii serotypes 1–5, 8, 10, 12–14, collected between 1974 and 1985 from endemic cases of shigellosis in Ethiopia, and their Escherichia coli K12 transconjugants. Resistance factors (R factors) were further characterized by incompatibility testing.

Patterns of small plasmids, less than 15 kb, were similar within each of the individual S. boydii serotypes. Plasmids of about 3·3–3·7 kb were found in all strains of serotypes 2 and 4. Plasmids of about 4·3–4·6 kb were found in about 86% of strains. Serotypes 1, 2 and 3 were characterized by plasmids of about 5·6–5·7 kb. The 6·4·6–7 kb plasmid was found consistently in serotypes 1, 2, 3, 5, 8, 12 and 13 which were resistant to SSu or had an SSu resistance component in their phenotypes. Large plasmids (155–186 kb) were found in most S. boydii strains.

Conjugative drug resistance plasmids, most often coding for three or less drugs, were found in about 26% of drug resistant strains. R-factors, coding for AT resistance (in types 2 and 8), and ASSuT resistance (in type 4), were compatible with all reference plasmids tested. Plasmids belonging to incompatibility groups X and N were found in serotypes 5 and 10, respectively.

A cluster of four cases of haemolytic uraemic syndrome in children occurred in Northern Bohemia, Czech Republic, between 15 June and 7 July, 1995. All the cases had significantly elevated titres of anti-O157 lipopolysaccharide (LPS) antibodies as detected by the indirect haemagglutination assay. All but one of them had drunk unpasteurized goat's milk from the same farm within the week before the disease. Evidence of E. coli O157 infection was subsequently found in 5 of 15 regular drinkers of the farm's raw goat's milk; four of them were asymptomatic, 1 had mild diarrhoea at the end of June. Verocytotoxin 2-producing E. coli O157[ratio ]H7 strains of phage type 2 and of identical pulsed-field gel electrophoresis patterns were isolated from 1 of 2 farm goats and from 1 of the asymptomatic goat's milk drinkers. The frequency of anti-O157 LPS antibodies found among regular drinkers of the farm's raw goat's milk (33%; 5 of 15) was significantly higher than that found in control population (0%; none of 45) (P=0·0005; Fisher's exact test). Our findings indicate that goats may be a reservoir of E. coli O157[ratio ]H7 and a source of the infection for humans; raw goat's milk may serve as a vehicle of the pathogen transmission.

The epidemiology of notified cases of campylobacter gastroenteritis in adults in Nottingham Health District was investigated using a case-control study with a postal questionnaire to ascertain data on risk factors. Over a 14-month period 531 cases (a 73% response rate of all laboratory confirmed cases) and 512 controls replied.

Conditional logistic regression analysis was used to determine independent associations with infection. These included foreign travel (odds ratio (OR) 3·4; 95% confidence intervals (CI) 2·0–5·7), diabetes mellitus (OR 4·1, CI 1·1–17), medication with omeprazole (OR 3·5, CI 1·1–12) and H2 and H2 antagonists (OR 3·7, CI 1·3–15), contact with puppies (OR11·3, CI1·2–105), eating chicken (OR 1·4, CI 1·1–1·8) and drinking milk from bottles with tops damaged by a bird (OR 3·3, CI 1·0–11). Preparing main meals (OR 0·9, CI 0·8–1·0) and drinking delivered milk (OR 0·6, CI 0·4–0·9) were associated with a reduced risk of campylobacter infection.

Foreign travel was reported in 25% of cases and another 15% had significant associations with other risk factors. The majority of cases, 60%, remained unexplained, indicating the need for further evolution of sporadic cases.

Mycobacterium ulcerans, the organism which causes Buruli or Bairnsdale ulcer, has never been isolated in culture from an environmental sample. Most foci of infection are in tropical regions. The authors describe the first 29 cases of M. ulcerans infection from a new focus on an island in temperate southern Australia, 1992–5. Cases were mostly elderly, had predominantly distal limb lesions and were clustered in a small region in the eastern half of the main town on the island. The authors suspected that an irrigation system which lay in the midst of the cluster was a source of infection. Limitation of irrigation was associated with a dramatic reduction in the number of new cases. These findings support the hypothesis that M. ulcerans has an aquatic reservoir and that persons may be infected directly or indirectly by mycobacteria disseminated locally by spray irrigation.

We report here a new and critical determinant of the effectiveness of hand hygiene procedures, namely the amount of residual moisture left on the hands after washing and drying. When samples of skin, food and utilities were touched with wet, undried hands, microbial numbers in the order of 68000, 31000 and 1900 respectively translocated to these representative surfaces. Bacterial numbers translocating on touch contact decreased progressively as drying with an air or cloth towel system removed residual moisture from the hands. A 10 s cloth towel–20 s air towel protocol reduced the bacterial numbers translocating to skin, food and utilities on touch contact to 140, 655 and 28 respectively and achieved a 99·8, 94 and 99% reduction in the level of bacterial translocation associated with wet hands. Careful hand drying is a critical factor determining the level of touch-contact-associated bacterial transfer after hand washing and its recognition could make a significant contribution towards improving handcare practices in clinical and public health sectors.

Two phenotypes of human influenza A(H1N1) virus are currently circulating in Japan. One (group 1) agglutinates both chicken and goose red blood cells (CRBC and GRBC), the other (group 2) agglutinates GRBC but not CRBC. In the 1995/6 season, group 2 viruses accounted for 70% of the H1N1 viruses isolated in MDCK cells. The 1995/6 viruses were located on two branches of the genetic tree. One branch contained both group 1 and group 2 viruses and the other branch contained only group 2 viruses. Group 2 viruses had aspartic acid at residue 225 in the haemagglutinin (HA) protein, the key amino acid residue for group 2 phenotype. The HA protein of group 1 viruses had a change from aspartic acid to asparagine at residue 225 and the expressed HA protein of these viruses adsorbed CRBC. Serial passage of group 2 viruses in MDCK cells or embryonated chicken eggs caused these viruses to gain the ability to agglutinate CRBC. MDCK-adapted viruses had the same amino acid sequences of HA polypeptide as the original ones, but egg-adapted viruses had changed amino acid sequences. The expressed HA protein from one egg-adapted virus that originally belonged to group 2 adsorbed CRBC.

The effectiveness of influenza vaccination in reducing hospitalization of people with diabetes for influenza, pneumonia, or diabetic events during influenza epidemics was assessed in a case control study in Leicestershire, England. Cases were 80 patients on the Leicestershire Diabetes Register who were admitted and discharged from hospital with International Classification of Disease codes for pneumonia, bronchitis, influenza, diabetic ketoacidosis, coma and diabetes, without mention of complications, during the influenza epidemics of 1989–90 and 1993. One hundred and sixty-controls, who were not admitted to hospital during this period, were randomly selected from the Register. Immunization against influenza was assessed in 37 cases and 77 controls for whom consent was obtained to access their clinical notes and for whom notes were available. Significant association was detected between reduction in hospitalization and influenza vaccination during the period immediately preceding an epidemic. Multiple logistic regression analysis estimated that influenza vaccination reduced hospital admissions by 79% (95% CI 19–95%) during the two epidemics, after adjustment for potential confounders.

The prevalence of antibody against hepatitis C virus (anti-HCV) and five hepatitis B virus markers (HBVM) was measured in 176 Chinese drug addicts, of whom 23 were AIDS patients. Of 176 drug addicts, 147 were members of ethnic minorities while 29 were Han, the majority ethnic group. The total prevalence rates of anti-HCV and HBVM were 35·8% and 50·6% respectively, significantly different (P<0·01). Anti-HCV and HBVM were together found in 22·7%. Similar prevalence rates were found among the different ethnic groups. Among the ethnic minorities, there was a significantly higher prevalence rate of anti-HCV in intravenous drug addicts (IVDA, 51·1%) than in oral drug addicts (20·3%). Furthermore, the prevalence of anti-HCV was significantly higher in needle-sharing abusers (60·4%) than in non-needle sharing ones (37·1%, P<0·05). The prevalence of HBVM was also significantly higher in needle-sharing abusers (69·8%) than in non-needle sharing ones (34·3%). Prevalence of HBsAg was significantly higher in drug abusers with AIDS (47·8%) than in IVDA only (16·1%). The anti-HCV positive rates among ethnic minority people were: for the Yi people 69·2%, the Hui 55·6%, the Bai 53·9%, the Dai 26·8% and the Wa 23·1%. No obvious difference was identified for HBVM. The prevalence rates of HCV, HBV and HCV+HBV in IVDA showed no significant difference (P>0·05) between the two regions. HIV, HCV and HBV infections may promote each other and be related to needle-sharing behaviour in drug abuse and to different subcultures and living habits.

To determine the prevalence and routes of transmission of hepatitis C virus (HCV) infection in Hafizabad, Pakistan, we collected sera in 1993 from a geographically based random sample of residents, and in 1994 identified 15 HCV-infected individuals (cases) and 67 age and sex matched uninfected individuals (controls). Initially we approached 504 households, and collected serum from a randomly selected household member in 309 (64%). Twenty persons (6·5%) had anti-HCV antibody; 31% percent had hepatitis B core antibodies, and 4·3% had hepatitis B surface antigen. In the case-control study, persons who received more therapeutic injections (categorized as averaging 1, 2–4, 5–9 or >10 injections per year in the previous 10 years) were more likely to be infected with HCV (odds ratio 0, 1·5, 2·5 and 6·9 respectively, P=0·008) compared to persons averaging 0 injections per year. Efforts to limit therapeutic injections to only those that are medically indicated and that use sterile equipment are essential in order to prevent transmission of HCV.

An outbreak of trichinosis occurred during January 1995 in a south Lebanese village with a population of 800–1000 persons. The estimated number of persons treated for a Trichinella-like illness was 200. Sixty-three persons sought medical attention at a local infirmary: 44 of them were diagnosed as having trichinosis or suspected trichinosis according to their clinical symptoms, signs and laboratory tests. An environmental investigation indicated that the source of infection was pork obtained from a single butcher in the village and consumed uncooked, as an ingredient of ‘kubeniye’ (a local dish), during Christmas and New Year's meals. Sera of patients, suspected patients, and asymptomatic controls were tested for the presence of anti-Trichinella antibodies. Eight (89%) of the 9 tested patients were positive, 1 (11%) was negative. Among the 7 suspected patients, 2 (28·5%) were positive, 3 (42·9%) had equivocal results, and 2 (28·5%) were negative. Among the 20 asymptomatic persons, 3 (15%) were positive, 12 (60%) negative and 5 (25%) had equivocal results. Specimens from the implicated pork meat were examined by microscopy and were found to contain encysted larvae of Trichinella spiralis. This outbreak of trichinosis is one of the largest reported. Previous outbreaks in Lebanon occurred under very similar circumstances, indicating a need to control and prevent the trading of pork meat that is not under veterinary control, and to increase the awareness of the population for this problem.

Admitted medical records, from January 1988 to December 1995, of 28 symptomatic amebic patients who lived in the east-southeast area of Tokyo were studied retrospectively, in order to find the present characteristics of symptomatic amebiasis due to Entamoeba histolytica in this area. Categorized by disease, there were 14 cases of colitis, 9 cases of liver abscess, 4 cases of colitis with liver abscess, and 1 case of liver abscess with brain abscess. Patients consisted of 26 Japanese males, 0 Japanese females, 1 non-Japanese male and 1 non-Japanese female. The mean age of colitis patients and liver abscess patients was 55·4 years old and 41·3 years old, respectively. The presumed place of contraction was Japan in 64% of the patients. Forty-eight percent of male patients indicated that they engaged in homosexual or bisexual practices, and 36% of male patients who denied such sexual practices or did not answer the question had no history of marriage. Positive rate of serum titre for Treponema pallidum hemagglutination test (TPHA) and human immunodeficiency virus antibody was 42·9% and 0%, respectively. Sixty-seven percent of TPHA-positive patients indicated that they engaged in male homosexual or bisexual practices. Zymodeme patterns of E. histolytica isolated from 4 colitis patients were XIV in 1 case and II in 3 cases. Symptomatic amebiasis in the east-southeast area of Tokyo is a disease which predominantly afflicts males, especially those in their middle age, and most patients contract the disease in Japan. The high rates of patients who engaged in male homosexual or bisexual practices and the high rates of patients with positive TPHA suggest that amebiasis is likely to be sexually transmitted disease in homosexual and bisexual men in the east-southeast area of Tokyo, and zymodeme II may be the predominant type in symptomatic amebic colitis in this area.

In a survey of five villages in the Eastern Highlands of Papua New Guinea, Serpulina pilosicoli was isolated from rectal swabs from 113 of 496 individuals (22·8%). Colonization rates ranged from 22·6–30·1% in four of the villages but was only 8·6% in the other village. In comparison colonization was demonstrated in only 5 of 54 indigenous people (9·3%) and none of 76 non-indigenous people living in an urban environment in the same region. Colonization did not relate to reported occurrence of diarrhoea, age, sex, or length of time resident in a village. A second set of 94 faecal specimens was collected from 1 village 6 weeks after the first set. S. pilosicoli was isolated from 27 of 29 individuals (93·1%) who were positive on the first sampling and from 7 of 65 individuals (10·8%) who previously were negative. In this case, isolates were significantly more common in watery stools than in normal stools. The annual incidence of infection in the village was calculated as 93·6%, with an average duration of infection of 117 days. S. pilosicoli could not be isolated from any village pig (n=126) despite its confirmed presence in 17 of 50 commercial pigs (34·0%) sampled at a local piggery. Four of 76 village dogs (5·3%) and 1 of 2 village ducks were colonized with S. pilosicoli, suggesting the possibility of cross transmission between humans and animals.

Partial nucleotide sequence of the capsid polypeptide coding gene 1D (VP1) was determined for 68 serotype O foot-and-mouth disease viruses isolated between 1983 and 1995 from outbreaks occurring in Saudi Arabia. The sequences were compared with previously published sequences: 14 viruses of Middle Eastern origin (isolated between 1987 and 1991); and with four vaccine virus strain sequences, three originating from the Middle East (O1/Turkey/Manisa/69, O1/Sharquia/Egypt/72 and O1/Israel/2/85) and one from Europe (O1/BFS 1860/UK/67). The virus isolates from Saudi Arabia and the Middle East vaccine virus strains formed a related genetic group distinct from the European O1virus. Within this large group 12 distinct genetic sublineages were observed.

Enterotoxigenic Escherichia coli (ETEC) adhere to the intestinal mucosa by a number of fimbrial colonization factors (CFs) that have been claimed to induce only type-specific immunity. However, adult Bangladeshi patients infected with CFA/I-expressing bacteria, developed significant plasma IgA antibody responses, as determined by enzyme-linked immunosorbent assay, not only against the homologous fimbriae but also against several heterologous CFs, i.e. CS1, CS2, CS4 and PCFO166 fimbriae. In contrast, North American volunteers, who had probably not been infected by ETEC previously, responded with serum IgA against CFA/I fimbriae but not against any other CFs after symptomatic infection with CFA/I-expressing ETEC. Thus, infection with CFA/I-expressing bacteria may boost immune responses against CFs with a related amino acid sequence in previously primed subjects.