Vero cytotoxin-producing Escherichia coli O157 (VTEC O157) infections are a threat to public health. VTEC O157 has been isolated from gulls but evidence of transmission to humans from birds has not been reported. We recount an incident of VTEC O157 infection affecting two sibling children who had no direct contact with farm animals. An outbreak control team was convened to investigate the source of infection, its likely mode of transmission, and to advise on control measures. Human and veterinary samples were examined and the human isolates were found to be identical to an isolate from a sample of bird (rook) faeces. Cattle, rabbit and environmental samples were negative. This report provides evidence that birds may act as intermediaries for human infection with VTEC O157.

Pertussis is an infectious respiratory disease for which mass vaccination is an effective preventive strategy. In many developed countries, where high vaccination coverage has been maintained for approximately 50 years, re-emergence of the disease has been observed in all age groups. In the municipality of Rio de Janeiro (RJ), where vaccination started in the 1980s, surveillance data show no sign of disease re-emergence. We developed a mathematical model that incorporates the major demographic aspects of a large urban centre in a developing nation, in addition to the most important epidemiological aspects of disease transmission. Parameter values were estimated based on RJ demographic and vaccine coverage data. Overall, all vaccination strategies determined a major decrease (over 95% decrease when compared to the pre-vaccine era) in the incidence of primary infections (occurring in individuals who have never been immunized through infection or vaccine). On the other hand, the strategies (a) three doses at age 2–11 months, (b) three doses plus booster at age 12–23 months, (c) three doses plus booster at age 4–5 years, and (d) three doses plus both boosters, differently affected the incidence of secondary infections (occurring in previously infected/vaccinated individuals). Given that the immunity against pertussis wanes with time and that the infectious agent has not been eliminated from the population, it is expected that pertussis will continue to be a problem in RJ. Actually, since immunity acquired from vaccine wanes faster than disease-acquired immunity and the possibility of natural boosters has decreased with mass vaccination, an increase in the incidence of secondary infections among older age groups is expected (and predicted by the model). Possible explanations as to why this dynamics is not captured by the RJ surveillance system are discussed. A poorly effective surveillance system and a lack of awareness regarding loss of immunity and the possibility of pertussis infection in older age groups are among them. Finally, we bring attention to the need of (i) field studies for the measurement of pertussis incidence in adolescents and adults; (ii) better understanding of the transmission dynamics currently occurring in RJ, and (iii) re-evaluation of vaccination strategies with the possible introduction of acellular vaccines for the vaccination of older individuals.

The aim of this study is to assess the effects of immigration from countries with a high prevalence of tuberculosis (HPCs), of HIV/AIDS prevalence, and the ageing of the indigenous population, on tuberculosis distribution in a low-prevalence area (LPCs), the Piedmont Region of Italy. Tuberculosis incidence and HIV cases were identified by linking records from the surveillance systems. Overall, 640 tuberculosis cases were identified and crude annual incidence was found to be 17·3/100000. The incidence rate ratio for HIV infection as a risk factor for tuberculosis (11·4 and 51·9 among individuals from HPCs and LPCs respectively) was greater than that for immigration from HPCs (6·7 and 30·9 among HIV+ and HIV− individuals). Immigration accounted for a larger number of incident cases [population attributable risk % (PAR %): 31·8 and 52·8% among HIV+ and HIV− individuals] than did HIV infection (PAR %: 5·4 and 11·1% among individuals from HPCs and LPCs). Efforts should be made to identify and treat young immigrants from HPCs.

Female sex workers in Europe have low levels of sexually transmitted infections, attributable to condom use. The aim of this paper is to describe the seroepidemiology of HSV-1 and HSV-2 in female sex workers in London by using a 15-year prospective study of 453 sex workers. The seroprevalence of HSV-1 was 74·4% and independently associated with birth in a ‘transitional country’ (OR 5·4, 95% CI 1·61–18·20). The seroprevalence of HSV-2 was 60% and declined over time; it was also independently associated with time in sex work (OR 2·12, 95% CI 1·23–3·65) and birth in a ‘developing country’ (OR 2·95, 95% CI 1·34–6·48). We show that a cohort of sex workers with extensive condom use and little known sexually transmitted infection have high levels of HSV-1 and HSV-2 infection, suggesting that condoms may not be universally protective. Sex workers are candidates for HSV vaccine efficacy or intervention studies.

The chemotactic response of Vibrio cholerae O1 towards the mucilaginous sheath of Anabaena sp. was investigated by capillary tube method using a virulent strain of V. cholerae O1, El Tor, Ogawa (3083-T) and its isogenic mutant (HAP-1-T) that lacks the hap gene, which codes for mucinase (HA/protease). Homogenates of Anabaena sp. and purified mucin were used in this study as chemoattractants. Results showed 5·7% bacterial accumulation of wild-type V. cholerae O1 towards 4% homogenates of Anabaena sp. whereas, its mutant (hap−) showed 2·9% accumulation after 90 min. The higher percentage of attraction of wild-type V. cholerae O1 than the mutant (hap−) towards mucin and the homogenates of Anabaena sp. might be due to the activity of mucinase. These results indicate the role of mucinase in the chemotactic motility of V. cholerae O1 towards Anabaena sp.

We evaluated three established statistical models for automated ‘early warnings’ of disease outbreaks; counted data Poisson CuSums (used in New Zealand), the England and Wales model (used in England and Wales) and SPOTv2 (used in Australia). In the evaluation we used national Swedish notification data from 1992 to 2003 on campylobacteriosis, hepatitis A and tularemia. The average sensitivity and positive predictive value for CuSums were 71 and 53%, for the England and Wales model 87 and 82% and for SPOTv2 95 and 49% respectively. The England and Wales model and the SPOTv2 model were superior to CuSums in our setting. Although, it was more difficult to rank the former two, we recommend the SPOTv2 model over the England and Wales model, mainly because of a better sensitivity. However, the impact of previous outbreaks on baseline levels was less in the England and Wales model. The CuSums model did not adjust for previous outbreaks.

A multidrug-resistant clonal group (CgA) of Escherichia coli was shown to cause half of all trimethoprim–sulphamethoxazole (TMP–SMZ)-resistant urinary tract infections (UTIs) in a college community between October 1999 and January 2000. This second study was conducted to determine the fate of CgA. Urine E. coli isolates from women with UTI, collected between October 2000 and January 2001, were tested for antibiotic susceptibility, O serogroup, ERIC2 PCR and DNA macrorestriction patterns using pulsed-field gel electrophoresis. The proportion of UTIs caused by CgA declined by 38% (P<0·001) but the prevalence of resistance to TMP–SMZ did not change. Six additional clonal groups were identified and these were responsible for 32% of TMP–SMZ-resistant UTIs. The temporal decline in the proportion of UTIs caused by CgA provides evidence that CgA caused a community outbreak of UTI. The fluctuation and occurrence of other E. coli clonal groups in this community suggest that a proportion of community-acquired UTIs may be caused by E. coli disseminated from one or more point sources.

We analysed the characteristics of the pregnancies with a previously undetected HIV infection in a national observational study of pregnant women with HIV in Italy. In a total of 443 pregnancies with available date of HIV diagnosis, 118 were characterized by a previously undetected HIV infection (26·6%, 95% CI 22·5–30·8). The following factors were independently associated with this occurrence in a multivariate analysis (adjusted odds ratios; 95% CIs): foreign nationality (5·1, 2·8–9·3); no pre-conception counselling (35·9, 4·8–266·1); first pregnancy (2·1, 1·2–4·0); asymptomatic status (6·8, 1·5–30·6). Women with previously undetected infection started antiretroviral treatment significantly later during pregnancy (P<0·001). Missed diagnosis was responsible for one case of transmission. A high rate of previously undetected HIV infection was observed. This suggests a good HIV detection during pregnancy, but also the need to reinforce HIV testing strategies among women of childbearing age. We identified some determinants which may be considered for intervention measures.

Mass gatherings are believed to increase the transmission of infectious diseases although surveillance systems have shown a low impact. The Catholic Jubilee was held in Rome, Italy in 2000. We conducted a case-control study to analyse the risk factors of giardiasis among residents. All diseases reported to the laboratory surveillance system from January 2000 to May 2001 were compared with hospital controls concurrently selected in the same season as cases and frequency-matched for age and birth country. Fifty-two cases (44·1%) and 72 controls were enrolled. In the multivariable analysis factors associated with giardiasis among adults were: travelling abroad (OR 24·2, P>0·01), exposure to surface water (OR 4·80, P=0·05), high educational level (OR 3·8, P=0·03). Having a maid from a high-prevalence country was independently associated (OR 2·3) although not statistically significant. This is the only exposure that changed during the Jubilee.

To determine factors associated with fetal growth, preterm delivery and stillbirth in an area of high malaria transmission in Southern Malawi, a cross-sectional study of pregnant women attending and delivering at two study hospitals was undertaken. A total of 243 (17·3%) babies were preterm and 54 (3·7%) stillborn. Intra-uterine growth retardation (IUGR) occurred in 285 (20·3%), of whom 109 (38·2%) were low birthweight and 26 (9·1%) preterm. Factors associated with IUGR were maternal short stature [adjusted odds ratio (AOR) 1·6, 95% confidence interval (CI) 1·0–2·5]; primigravidae (AOR 1·9, 95% CI 1·4–2·7); placental or peripheral malaria at delivery (AOR 1·4, 95% CI 1·0–1·9) and maternal anaemia at recruitment (Hb <8 g/dl) (AOR 1·9, 95% CI 1·3–2·7). Increasing parasite density in the placenta was associated with both IUGR (P=0·008) and prematurity (P=0·02). Factors associated with disproportionate fetal growth were maternal malnutrition [mid-upper arm circumference (MUAC) <23 cm, AOR 1·9, 95% CI 1·0–3·7] and primigravidae (AOR 1·8, 95% CI 1·0–3·1). Preterm delivery and stillbirth were associated with <5 antenatal care visits (AOR 2·2, 95% CI 1·3–3·7 and AOR 3·1, 95% CI 1·4–7·0 respectively) and stillbirth with a positive Venereal Disease Research Laboratory (VDRL) test (AOR 4·7, 95% CI 1·5–14·8). Interventions to reduce poor pregnancy outcomes must reduce the burden of malaria in pregnancy, improve antenatal care and maternal malnutrition.

During 1989–2002, we studied the antimicrobial resistance of 3928 blood culture isolates of Salmonella enterica serotype Typhi (S. Typhi) in Dhaka, Bangladesh. Overall 32% (1270) of the strains were multidrug-resistant (MDR, resistant to chloramphenicol, ampicillin and trimethoprim–sulphamethoxazole); first detected in 1990 (rate of 8%), increased in 1994 (44%), declined in 1996 (22%, P<0·01 compared to 1994) and re-emerged in 2001 (36%) and 2002 (42%, P<0·01 compared to 1996). An increased MIC of ciprofloxacin (0·25 μg/ml) indicating decreased susceptibility to ciprofloxacin was detected in 24 (18·2%) out of 132 randomly selected strains during 1990–2002; more frequently in MDR than susceptible strains (46·3% vs. 5·5%, P<0·001), and the proportion of them rose to 47% in 2002 from 8% in 2000 (P<0·01). Ciprofloxacin (5 μg) disk diffusion zone diameters of [les ]24 mm as break-point had 98% sensitivity and 100% specificity when compared with a ciprofloxacin MIC of 0·25 μg/ml as break-point for decreased susceptibility; being a useful and easy screen test. All strains were susceptible to ceftriaxone. The emergence of MDR S. Typhi with decreased ciprofloxacin susceptibility will further complicate the therapy of typhoid fever because of the lack of optimum treatment guidelines.

National policies for chemoprophylaxis after single cases of meningococcal disease in day-care or nursery settings vary across Europe. We carried out a multi-national retrospective study to compare the effectiveness of different policies. Countries were divided into those recommending chemoprophylaxis only to close contacts (policy A, close) and those recommending chemoprophylaxis for all children in the same nursery (policy B, mass). Country-specific relative risk (RR) of a cluster was defined as the ratio of the number of clusters observed to the number of clusters expected by chance. In total, 37 clusters were identified between 1 January 1993 and 31 December 2002. After adjusting for marked heterogeneity in RR by country, the ratio of RR between countries suggested possible benefit from mass prophylaxis (RR ratio 3·8, 95% CI 0·7–22·0), although the difference was not statistically significant (P=0·22). The costs of this approach and the low risk of clustering need to be taken into account when deciding national policy.

Enteric illness outbreaks among middle-/high-school students in consecutive semesters of an educational farm programme were investigated with retrospective cohort studies. During the first outbreak, 31/92 (34%) interviewed students were ill. Risk factors included participating in animal science class (RR 8·1, 95% CI 1·2–55·2) and contact with calves (RR 4·2, 95% CI 1·1–16·2). Stool samples from seven students and two calves yielded Cryptosporidium parvum. Students cared for animals in street clothes and practised poor hand washing. During the second outbreak, 37/81 (46%) interviewed animal science students were ill. Risk factors included having visible manure on hands, and wearing coveralls and boots. Stool samples from seven students and eight calves yielded C. parvum. Student hand washing was still inadequate. Coveralls/boots were cleaned infrequently and removed after hand washing. These outbreaks of cryptosporidiosis resulted from calf contact and inadequate hygiene practices. The failure to adequately implement recommended interventions contributed to the second outbreak.

Much data has been gathered by the EWGLINET scheme on the distribution of cases of travel-associated Legionnaires' disease (TALD) by country of infection, but less analysis has been carried out on the distribution of these cases within countries. Travel-associated cases with onset in 2002 linked to France, Italy, Spain and Turkey were mapped. Rates of Legionnaires' disease per 100000 tourists were calculated for internal and foreign visitors for the regions of each country, and mapped. Rates of 1·5 cases/100000 and 2 cases/100000 tourists were classified as ‘high’ and ‘very high’ respectively. Cases of TALD were concentrated in certain regions, but when rates were calculated using tourist data, the results were relatively constant throughout each country. Rates were higher among foreign visitors than internal visitors; three of the countries had at least one region with ‘high’ rates, whilst Turkey additionally had three regions with ‘very high’ rates.

In May 2000, public health authorities in Dublin, Ireland, identified a cluster of unexplained severe illness among injecting drug users (IDUs). Similar clusters were also reported in Scotland and England. Concurrent investigations were undertaken to identify the aetiology and source of the illnesses. In Dublin, 22 IDUs were identified with injection-site inflammation resulting in hospitalization or death; eight (36%) died. Common clinical findings among patients with severe systemic symptoms included leukaemoid reaction and cardiogenic shock. Seventeen (77%) patients reported injecting heroin intramuscularly in the 2 weeks before illness. Of 11 patients with adequate specimens available for testing, two (18%) were positive by 16S rDNA PCR for Clostridium novyi. Clinical and laboratory findings suggested that histotoxic Clostridia caused a subset of infections in these related clusters. Empiric treatment for infections among IDUs was optimized for anaerobic organisms, and outreach led to increased enrolment in methadone treatment in Dublin. Many unique legal, medical, and public health challenges were encountered during the investigation of this outbreak.