Skin infections are highly prevalent in many Australian Aboriginal communities. This study aimed to determine the prevalence of group A streptococcus (GAS) and Staphylococcus aureus in skin sores of Indigenous people living in an urban setting. We undertook a cross-sectional study of 173 children and youths attending the Wuchopperen Clinic (Cairns) for treatment of skin infections. Participants were interviewed using a structured questionnaire, and a skin lesion swab obtained. The median age was 5·3 years, with 42% identifying themselves as Torres Strait Islanders and 34% as Aboriginal. Impetigo (65%) was the most frequent diagnosis reported followed by scabies (19%); 79% of the lesions had erythema and 70% had exudate. Of 118 lesions, 114 were positive for pathogenic bacteria, with GAS isolated in 84 cases and S. aureus in 92; both these species were recovered from 63 lesions. Significant diversity of emm-types of GAS was associated with skin lesions in Indigenous patients (22 emm-types identified). Fifteen of the 92 S. aureus isolates were suggestive of being community-acquired on the basis of antimicrobial susceptibility profile and nine of these strains were co-cultured from nine lesions. These results have implications for future changes of antibiotic policies for the treatment of skin infections in this population.

Expansion of dengue has been attributed to urbanization. To test this concept, we examined dengue transmission intensities in Thailand. We used the inverse of mean age of dengue haemorrhagic fever (DHF) cases as a surrogate of dengue transmission intensity (or force of infection). The transmission intensity in Bangkok decreased rapidly since the mid-1990s, to levels that are currently lower than in other regions. Regression analysis revealed that transmission intensity is highest in the Northeastern rural region, mainly due to scarcity of private water wells. Private wells reduce the need for household water containers, the major breeding sites for vectors. Cumulatively, these results show that urbanization is not necessarily associated with intense dengue transmission in Thailand. Paradoxically, the DHF incidence in Bangkok has surpassed other regions despite declines in transmission intensity. This finding implies the existence of endemic stability (i.e. low incidence of a clinical illness in spite of high transmission intensity).

The prevalence of Salmonella in four layer farms in eastern Japan was investigated between 2004 and 2006 to determine the role of roof rats (Rattus rattus) in the epizootology of Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis). Persistent S. Enteritidis and S. Infantis contamination of the environment and pooled egg samples were detected in three out of four layer farms. A total of 113 (13·3%) and 158 (18·6%) out of 851 rats examined were positive for S. Enteritidis and S. Infantis, respectively. By pulsed-field gel electrophoresis, only one indistinguishable pulsed-field pattern was yielded by S. Enteritidis strains from rats, eggs and environmental samples from each of the two contaminated layer farms. Although, a variety of pulsed-field patterns were generated by S. Enteritidis isolates from rats, eggs, and the environment of the other contaminated farms, there are, however, some S. Enteritidis strains that are closely related clones. These results suggest that roof rats are carriers of S. Enteritidis and S. Infantis and that persistent S. Enteritidis and S. Infantis infections in a rat population may play an important role in the spread and maintenance of these pathogens inside the layer premises.

We examined the prevalence of mumps antibodies in the Israeli population in relation to mumps vaccination policy and past and subsequent incidence of disease. The levels of specific IgG antibodies against mumps were tested in 3330 residual sera collected during 1997–1998 from an age-stratified population sample. Against the background of a consistent MMR vaccination coverage of >90%, the age- and sex-adjusted seropositivity to mumps was 77·0%. No significant differences between genders were found. Seropositivity in the 10–13 years age group, born just before the introduction of the MMR vaccine, was the lowest (59%). These birth cohorts were the target of an outbreak of mumps in 2005 that occurred among high-school students and military recruits. A trend of waning immunity was observed between the first and second vaccine doses. The seroepidemiological data demonstrate that immunity levels below the herd immunity threshold, along with social mixing and crowded conditions facilitated the occurrence of mumps outbreaks. Periodical serosurveys are an essential component in the evaluation of the vaccination policy against mumps.

Legionnaires' disease (LD) is an aetiology of community-acquired bacterial pneumonia in adults, with a high case-fatality ratio (CFR). We conducted a matched case-control study to identify risk factors for sporadic, community-acquired LD. Cases of sporadic, community-acquired and biologically confirmed LD, in metropolitan France from 1 September 2002 to 31 September 2004, were matched with a control subject according to age, sex, underlying illness and location of residence within 5 km. We performed a conditional logistic regression on various host-related factors and exposures. Analysis was done on 546 matched pairs. The CFR was 3·5%. Age ranged from 18–93 years (mean 57 years), with a 3·6 male:female sex ratio. Cases were more likely to have smoked with the documentation of a dose-effect relation, to have travelled with a stay in a hotel (OR 6·1, 95% CI 2·6–14·2), or to have used a wash-hand basin for personal hygiene (OR 3·5, 95% CI 1·6–7·7) than controls. Tobacco and travel have been previously described as risk factors for LD, but this is the first time that such a dose-effect for tobacco has been documented among sporadic cases. These findings will provide helpful knowledge about LD and help practitioners in identifying patients at high risk.

Asymptomatic enteric infections are important where sequelae or protection from subsequent illness is an outcome measure. The use of reverse transcription–polymerase chain reaction (RT–PCR) to identify asymptomatic enteric infections in a birth cohort followed for rotaviral infections in a south Indian urban slum is reported. Of 1191 non-diarrhoeal samples from 371 children collected in May–June 2003, 22 (1·9%) were positive by ELISA. A total of 147 (40·6%) of 362 samples tested by VP6 RT–PCR were positive. In those samples that could be typed, a high diversity of G types including G1, G2, G4, G8, G9 and G10, and a high proportion (34·4%) of mixed infections were detected. Noroviruses were identified in 6/28 (21·4%) samples tested. The identification of infections undetectable by conventional techniques indicates the importance of the use of sensitive diagnostic techniques in research studies. Asymptomatically infected children may also act as a source of infection for other susceptible hosts.

During the southern hemisphere winter of 2006 New Zealand experienced a significant increase in the number of reported cases of Campylobacter infection. In total, 112 Campylobacter isolates from eight district health boards (DHBs) located across New Zealand were submitted for PFGE, MLST and Penner serotyping analysis. Distinct clusters of Campylobacter isolates were identified, several of which were composed of isolates from up to five different DHBs located on both the North and South islands of New Zealand. One sequence type, ST-474, was identified in 32 of the 112 isolates and may represent an endemic sequence type present in New Zealand. The spatial pattern of genotypes, combined with the generalized increase in notifications throughout the country is consistent with a common source epidemic, most likely from a source contaminated with the dominant sequence types ST-474 and ST-190 and may also represent widely distributed stable clones present in New Zealand.

Recurrent epidemics of influenza are observed seasonally around the world with considerable health and economic consequences. A key quantity for the control of infectious diseases is the reproduction number, which measures the transmissibility of a pathogen and determines the magnitude of public health interventions necessary to control epidemics. Here we applied a simple epidemic model to weekly indicators of influenza mortality to estimate the reproduction numbers of seasonal influenza epidemics spanning three decades in the United States, France, and Australia. We found similar distributions of reproduction number estimates in the three countries, with mean value 1·3 and important year-to-year variability (range 0·9–2·1). Estimates derived from two different mortality indicators (pneumonia and influenza excess deaths and influenza-specific deaths) were in close agreement for the United States (correlation=0·61, P<0·001) and France (correlation=0·79, P<0·001), but not Australia. Interestingly, high prevalence of A/H3N2 influenza viruses was associated with high transmission seasons (P=0·006), while B viruses were more prevalent in low transmission seasons (P=0·004). The current vaccination strategy targeted at people at highest risk of severe disease outcome is suboptimal because current vaccines are poorly immunogenic in these population groups. Our results suggest that interrupting transmission of seasonal influenza would require a relatively high vaccination coverage (>60%) in healthy individuals who respond well to vaccine, in addition to periodic re-vaccination due to evolving viral antigens and waning population immunity.

Many contradictory articles on the infectivity of non-culturable Campylobacter jejuni can be found. We studied the effect of non-culturable C. jejuni in an in vitro assay. To prevent the potential effect of a few culturable bacteria in the non-culturable suspension, INT-407 cells, which mimic the outer cell layer in the small intestines, were exposed to culturable C. jejuni suspensions with or without non-culturable C. jejuni. The number of bacteria adhering to and/or invading INT-407 cells and the IL-8 secretion were measured. No differences were found between bacterial suspensions with or without non-culturable C. jejuni added. These findings show that non-culturable C. jejuni do not adhere to or invade INT-407 cells and do not induce an immune response. As previous studies showed a correlation between the used in vitro assays and the effect in vivo, our study strongly suggests that culturability is a good indicator of the risk for C. jejuni infection.

The distribution of Burkholderia pseudomallei was determined in soil collected from a rural district in Papua New Guinea (PNG) where melioidosis had recently been described, predominately affecting children. In 274 samples, 2·6% tested culture-positive for B. pseudomallei. Pulsed-field gel electrophoresis using SpeI digests and rapid polymorphic DNA PCR with five primers demonstrated a single clone amongst clinical isolates and isolates cultured from the environment that was commonly used by children from whom the clinical isolates were derived. We concluded that individuals in this region most probably acquired the organism through close contact with the environment at these sites. Burkholderia thailandensis, a closely related Burkholderia sp. was isolated from 5·5% of samples tested, an observation similar to that of melioidosis-endemic areas in Thailand. This is the first report of an environmental reservoir for melioidosis in PNG and confirms the Balimo district in PNG as melioidosis endemic.

Human immunodeficiency virus type 1 (HIV-1) epidemiology among residents of a rural agricultural plantation in Kericho, Kenya was studied. HIV-1 prevalence was 14·3%, and was higher among women (19·1%) than men (11·3%). Risk factors associated with HIV-1 for men were age (⩾25 years), marital history (one or more marriages), age difference from current spouse (⩾5 years), Luo ethnicity, sexually transmitted infection (STI) symptoms in the past 6 months, circumcision (protective), and sexual activity (⩾7 years). Among women, risk factors associated with HIV-1 were age (25–29 years, ⩾35 years), marital history (one or more marriages), age difference from current spouse (⩾10 years), Luo ethnicity, STI symptoms in the past 6 months, and a STI history in the past 5 years. Most participants (96%) expressed a willingness to participate in a future HIV vaccine study. These findings will facilitate targeted intervention and prevention measures for HIV-1 infection in Kericho.

Under-reporting of infectious gastrointestinal illness (IGI) in British Columbia, Canada was calculated using simulation modelling, accounting for the uncertainty and variability of input parameters. Factors affecting under-reporting were assessed during a cross-sectional randomized telephone survey. For every case of IGI reported to the province, a mean of 347 community cases occurred (5th and 95th percentile estimates ranged from 181 to 611 community cases, respectively). Vomiting [odds ratio (OR) 2·15, 95% confidence interval (CI) 1·03–4·49] and antibiotic use in the previous 28 days (OR 3·59, 95% CI 1·17–10·97) significantly predicted health-care visits in a logistic regression model. In bivariate analyses, physicians were significantly less likely to request stool samples from patients with vomiting (RR 0·09, 95% CI 0·01–0·65) and patients of North American as opposed to non-North American cultural groups (RR 0·38, 95% CI 0·15–0·96). Physicians were more likely to request stool samples from older patients (P=0·003), patients with fewer household members (P=0·002) and those who reported anti-diarrhoeal use following illness (RR 3·33, 95% CI 1·32–8·45). People with symptoms of vomiting were under-represented in provincial communicable disease statistics. Differential degrees of under-reporting must be understood before biased surveillance data can be adjusted.

Nine cases of brucellosis were identified in the city of Elche (Comunidad Valenciana, Spain) in two families of Moroccan immigrants. All of the patients had drunk unpasteurized raw milk from goats. Brucella melitensis biovar 3 was identified in clinical specimens. Preventive measures for brucellosis should be implemented among immigrant populations in Spain.

Lymphatic filariasis continues to cause severe morbidity and economic loss. The World Health Assembly (WHA) has passed a resolution to eliminate this disease by 2020. The major thrust of the elimination strategy is interrupting transmission by anti-parasitic treatment of entire communities. However, both vector density and community microfilaria load (CMFL) influence the intensity of transmission. Therefore, using a logistic regression approach a relationship has been established between the Risk of Infection Index (RII), vector density and CMFL. The present analysis indicates that there is no risk of transmission as long as the CMFL is maintained below 5 microfilaria (mf)/60 mm3 and the vector density per man-hour (MHD) is <25. However, transmission may continue when vector density is >25 and CMFL is <5 mf/60 mm3. In situations where CMFL is very high, parasitic control by mass administration may be cost effective in interrupting transmission. But at lower level of CMFL (<4 mf) and higher level of vector density it might be more cost effective to use vector control methods. A RII value <0·2 is considered to be the threshold for confirming interruption of transmission. Thus, the relationship has been depicted in the form of a probability matrix, which could be used for selecting an appropriate control strategy.

The prevalence, incidence and outcomes of haemolytic uraemic syndrome (HUS) and thrombotic thrombocytopaenic purpura (TTP) are not well established in adults or children from prospective studies. We sought to identify both outcomes and current management strategies using prospective, national surveillance of HUS and TTP, from 2003 to 2005 inclusive. We also investigated the links between these disorders and factors implicated in the aetiology of HUS and TTP including infections, chemotherapy, and immunosuppression. Most cases of HUS were caused by verocytotoxin-producing Escherichia coli (VTEC), of which serotype O157 predominated, although other serotypes were identified. The list of predisposing factors for TTP was more varied although use of immunosuppressive agents and severe sepsis, were the most frequent precipitants. The study demonstrates that while differentiating between HUS and TTP is sometimes difficult, in most cases the two syndromes have quite different predisposing factors and clinical parameters, enabling clinical and epidemiological profiling for these disorders.

We describe recent epidemiological changes in salmonellosis. Linking 1968–2000 National Salmonella Surveillance System to census data, we calculated population-based age- and sex-stratified rates of non-urinary salmonellosis for the top 30 non-typhoidal serotypes. Using 1996–1997, 1998–1999, and 2000–2001 population-based FoodNet surveys, we compared reported diarrhoea, medical visits, and stool cultures. Despite an overall female-to-male incidence rate ratio (FMRR) of 0·99, the sex-specific burden of salmonellosis varied by age (<5 years FMRR 0·92; 5–19 years 0·85; 20–39 years 1·09; 40–59 years 1·23, and ⩾60 years 1·08) and serotype (FMRR range 0·87 for Mississippi to 1·25 for Senftenberg). Serotype-specific FMRRs and median age (range 2 years for Derby to 29 years for Senftenberg) were related (correlation 0·76, P<0·0001). Recently, the relative burden of salmonellosis in women has increased. FoodNet data suggest that this change is real rather than due to differential reporting. Excess salmonellosis in women may reflect differences in exposure or biological susceptibility.

Our study aimed at analysing the changes in epidemiological features of leptospirosis cases from the hospital of Pointe à Pitre in Guadeloupe in 2003–2004 compared to reliable data in 1994–2001. Leptospirosis incidence increased fourfold during 2002–2004, a period with two El Niño events. Whereas the main risk factors were unchanged (male gender, occupational exposure, contact with cattle or pigs) a major role of rodent exposure emerged (52%, P=0·02, multivariate analysis). Interestingly, mean age of cases shifted to the older population (51·7 years vs. 43 years, P<0·05). Moreover, the Ballum serogroup rose dramatically (36% of incidence) competing with the Icterohaemorragiae serogroup (62%). However, severe forms were less recorded. Our data suggest that the changes in leptospirosis features could be related to exceptional meteorological events and their consequences on rodent populations. We propose the monitoring of rodent population and climatic data as a tool of management of leptospirosis in Guadeloupe.

The incidence of Legionnaires' disease has an uneven geographical distribution in Denmark, ranging from 3 to 70 notified cases per million inhabitants per year in different towns. We investigated the prevalence of antibodies to Legionella in the one town with a consistently high incidence (Randers, Aarhus County) and compared it with that of an area of average incidence (Vejle, Vejle County). Blood samples were collected from healthy blood donors in Randers (n=308) and in Vejle (n=400), and analysed for antibodies to Legionella by indirect immunofluorescence antibody test with L. pneumophila, L. micdadei, and L. bozemanii as antigens. Overall 22·9% of the donors had antibody titres of ⩾1:128; indicating that antibodies to Legionella are common in healthy individuals, and reflecting that the bacteria may be widely distributed in the environment. Surprisingly, the study did not reveal a higher prevalence in the hyperendemic area. Thus, the high incidence of notified cases in this particular town may not be attributed to an overall increased exposure of the general population.

Human rabies in China continues to increase exponentially, largely due to an inadequate veterinary infrastructure and poor vaccine coverage of naive dogs. We performed an epidemiological survey of rabies both in humans and animals, examined vaccine quality for animal use, evaluated the vaccination coverage in dogs, and checked the dog samples for the presence of rabies virus. The lack of surveillance in dog rabies, together with the low immunization coverage (up to 2·8% in rural areas) and the high percentage of rabies virus prevalence (up to 6·4%) in dogs, suggests that the dog population is a continual threat for rabies transmission from dogs to humans in China. Results also indicated that the quality of rabies vaccines for animal use did not satisfy all of the requirements for an efficacious vaccine capable of fully eliminating rabies. These data suggest that the factors noted above are highly correlated with the high incidence of human rabies in China.

We conducted a 31-month retrospective review of all laboratory-confirmed Streptococcus suis infections admitted to public hospitals in Hong Kong. Strain identification, serotyping and antibiotic susceptibility tests were conducted on S. suis isolates. Twenty-one sporadic cases were identified, comprising 18 (86%) males and 3 (14%) females. About half were patients aged ⩾65 years. More cases occurred during summer. Occupational exposure was documented in five (24%) cases. The estimated annual incidence was 0·09/100 000 in the general population and 32/100 000 in people with occupational exposure to pigs and raw pork. The primary clinical manifestations were meningitis (48%), septicaemia (38%) and endocarditis (14%). The case-fatality rate was 5%. All available isolates from 15 patients were serotype 2, sensitive to penicillin, ampicillin, ceftriaxone, but resistant to tetracycline. Injury prevention and proper handling of pigs or raw pork should be advocated to both at-risk occupational groups and the general population.