This study aimed to disentangle the independent contributions of Helicobacter pylori infections in mothers, fathers and siblings to the risk for the infection in the 11–13 years age group. Index children from a cross-sectional Stockholm school survey and their family members completed questionnaires and contributed blood samples. H. pylori serostatus was determined with an enzyme-linked immunosorbent assay and immunoblot. Fifty-four seropositive and 108 seronegative index children were included and 480 out of 548 family members contributed blood. In multivariate logistic regression modelling, having an infected mother (OR 11·6, 95% CI 2·0–67·9) or at least one infected sibling (OR 8·1, 95% CI 1·8–37·3) were risk factors for index child infection, whilst the influence of infected fathers was non-significant. Birth in high-prevalence countries was an independent risk factor (OR 10·4, 95% CI 3·4–31·3). H. pylori infections in mothers and siblings and birth in high-prevalence countries stand out as strong markers of infection risk amongst children in Sweden.

Three outbreaks of respiratory illness associated with human coronavirus HCoV-OC43 infection occurred in geographically unrelated aged-care facilities in Melbourne, Australia during August and September 2002. On clinical and epidemiological grounds the outbreaks were first thought to be caused by influenza virus. HCoV-OC43 was detected by RT–PCR in 16 out of 27 (59%) specimens and was the only virus detected at the time of sampling. Common clinical manifestations were cough (74%), rhinorrhoea (59%) and sore throat (53%). Attack rates and symptoms were similar in residents and staff across the facilities. HCoV-OC43 was also detected in surveillance and diagnostic respiratory samples in the same months. These outbreaks establish this virus as a cause of morbidity in aged-care facilities and add to increasing evidence of the significance of coronavirus infections.

A total of 455 highly tetracycline-resistant Escherichia coli strains were isolated from 84 healthy swine from abattoirs and it was found that 56·9, 43·1, 22·2, 15·4, 2·6 and 1·5% of strains were resistant to chloramphenicol, ampicillin, kanamycin, trimethoprim–sulphamethoxazole, ofloxacin and gentamicin respectively. Interestingly, E. coli strains isolated from certain finisher hog groups exhibited resistance against 2–7 antimicrobials, but strains isolated from multiparous sow groups in each herd were resistant to only 2–4 antimicrobial agents. When randomly selected 108 tetracycline-resistant isolates were tested for the presence of resistance genes, the following genes tet(A) (n=6), tet(B) (n=95), tet(D) (n=1) or both tet(A) and tet(B) (n=6) were found to be distributed among them. Furthermore, 52 isolates carried the integrase 1 gene and 24 strains gave five different PCR amplicon profiles using primers from the variable region of integron. Extensive nucleotide sequence analyses of these amplicons revealed the presence of dhfrI, dhfrXII, dfr17, aadA, aadA2, aadA5, aadA21, aacA4 and catB3 genes which code for different antibacterial resistance proteins.

Orf of the hand is an uncommon zoonotic infection caused by a dermotropic DNA virus that belongs to the Parapoxvirus genus of the family Poxviridae. It is transmitted to humans through contact with infected sheep and goats and is reported as an occupational disease. We report nine cases of human orf seen in the hands of individuals, who were not occupationally exposed, after the feast of sacrifice in Turkey. Three cases were teachers and six out of the nine were housewives. We observed musculoskeletal complications and misdiagnoses. It is important to consider human orf in the differential diagnosis of hand lesions to prevent overtreatment and complications.

(Reprinted from: Hayes W. The discovery of pneumococcal type transformation: an appreciation. J Hyg 1966; 64: 177–184.)

Griffith F. The significance of pneumococcal types. J Hyg 1928; 27: 113–159.

Human respiratory syncytial virus (hRSV) transmission dynamics are inherently cyclical, and the observed genetic diversity (between groups A and B) also appears to have a repeating pattern. A key unknown is the extent to which genetic variants interact immunologically, and thus impact on epidemiology. We developed a novel mathematical model for hRSV transmission including seasonal forcing of incidence and temporary intra- and inter-group partial immunity. Simultaneous model fits to data from two locations (England & Wales, UK, and Turku, Finland) successfully reproduced the contrasting infection dynamics and group A/B dominance patterns. Parameter estimates are consistent with direct estimates. Differences in the magnitude and seasonal variation in contact rate between the two populations alone could account for the variation in dynamics between these populations. The A/B group dominance patterns are explained by reductions in susceptibility to and infectiousness of secondary homologous and heterologous infections. The consequences of the observed dynamic complexity are discussed.

During 1998–2002, 124 microbiologically confirmed infections caused by shigatoxigenic Escherichia coli (STEC) were reported in Finland. Of these, 25 (20%) were associated with recent foreign travel. Temporal, geographical and type distribution of the domestically acquired infections (n=99) caused by strains of serogroup O157 (n=52) and non-O157 (n=47) were analysed further. The median age of the patients was 6·8 years (range 0·2–73·1 years). Of the index cases within 26 families, 71% were <5 years old. Family-related infections accounted for 49%, sporadic infections 39%, and 11% were associated with three clusters. Only strains of serogroup O157 carrying eae and stx2 or its variants caused separate clusters. The incidence of STEC infections was at its highest (0·64/100000) in 1998. Since 1999 it has declined considerably (0·17/100000 in 2002). STEC infections occurred in 14 hospital districts, mostly (28%) in the Helsinki region. However, the incidence was highest (10·3) in northwest Finland.

This is a review of existing data on the burden of shigellosis in Thailand to determine trends, vulnerable groups, predominant species and serotypes, and antimicrobial resistance patterns. Diarrhoea and dysentery morbidity and mortality data from 1991 to 1999 was collected from the routine surveillance system and demographic data from the government census. International and local literature published between 1988 and 2000 was systematically reviewed. Based on the routine surveillance system, the annual incidence of bacillary dysentery decreased from 1·3 to 0·2/10000 persons per year. The remaining burden is highest in children <5 years of age at 2·7/10000 persons per year. In comparison, a prospective study utilizing active surveillance found an incidence in children <5 years of age that was more than 100-fold higher at 640/10000 persons per year. Despite the decrease in morbidity and mortality based on routinely collected data, shigellosis remains an important problem in children <5 years of age in Thailand.

Estimation of the degree of undercount is important for disease surveillance. Capture–recapture techniques are now being used to evaluate the completeness of disease ascertainment. This study estimated the level of under-notification of giardiasis in the Auckland adult population using a capture–recapture method. Two independent datasets of giardiasis cases [ges ]15 years were generated from the 1998–1999 Auckland Giardiasis Study (AGS) case database and cases notified to Auckland Regional Public Health Services (ARPHS) for the same period of time. Cases were matched and under-notification was estimated using a two-sample capture–recapture method. During the 12-month period, 199 cases participated in the AGS and 413 cases were notified to ARPHS. The capture–recapture calculation indicated that only 49% of cases were notified. Under-notification by a factor of 2 obscures the true burden of giardiasis. Socio-economic conditions and water quality may influence disease notification inversely. Capture–recapture techniques are useful in evaluating the completeness of surveillance.

A survey of the microbial quality of table eggs sold in Trinidad was conducted. For 23 poultry layer farms each visited twice approximately 1 month apart, 25 pooled eggs constituted a composite sample, for 14 shopping malls each visited twice approximately 1 month apart, six pooled eggs made a composite sample and for a total of 102 other retailers across the country each visited once over a 4-month period, six pooled eggs constituted a composite sample. Swabs of egg shells and egg content were tested for selected bacteria. Twenty-four (13·0%), 68 (37·0%), and two (1·1%) of a total of 184 composite eggs (shells, egg content or both) sampled were positive for Salmonella, Escherichia coli, and Campylobacter respectively. All 184 samples tested were negative for Listeria spp. Salmonella was recovered from seven (3·8%) egg shell samples only compared with 14 (7·6%) egg content samples only positive for the pathogen. Fifty-two (28·3%) egg shell samples and seven (3·8%) egg content samples were positive for E. coli. Both isolates of Campylobacter coli originated from egg contents. Of a total of 24 composite egg samples positive for Salmonella, eight different serotypes of Salmonella were isolated from a total of 24 Salmonella-positive composite eggs of which S. Enteritidis was the most prevalent, 58·3% (14/24). Salmonella Georgia was isolated for the first time in Trinidad. Failure to properly handle or heat table eggs sold in Trinidad poses a potential health hazard to consumers because of their poor microbial quality.

We sought to determine the source of a norovirus outbreak among attendees of 46 weddings taking place during a single weekend. Norovirus-compatible illness was experienced by 332 (39%) of wedding guests surveyed; the outbreak affected up to 2700 persons. Illness was associated with eating wedding cake provided by a bakery common to the weddings (adjusted RR 4·5, P<0·001). A cake requiring direct hand contact during its preparation accounted for the majority of illness. At least two bakery employees experienced norovirus-compatible illness during the week preceding the weddings. Identical sequence types of norovirus were detected in stool specimens submitted by two wedding guests, a wedding hall employee, and one of the ill bakery employees. It is likely that one or more food workers at the bakery contaminated the wedding cakes through direct and indirect contact. These findings reinforce the necessity of proper food-handling practices and of policies that discourage food handlers from working while ill.

Phylogenetic relationships were examined for 70 Crimean-Congo haemorrhagic fever (CCHF) isolates from southern, central and West Africa, the Middle East and Greece using sequence data determined for a region of the S segment of the genome. Analysis revealed up to 18% genetic differences. Tree topology supports previous evidence for the existence of three groups of genetically related isolates, A, B and C. Within group A there are two clades: an African clade and a predominantly Asian clade comprising isolates from Pakistan, China, Iran, Russia and Madagascar. Group B includes isolates from southern and West Africa and Iran, and group C includes a single isolate from Greece. Despite the potential which exists for dispersal of the virus between Africa and Eurasia, it appears that circulation of the virus is largely compartmentalized within the two land masses, and the inference is that the geographic distribution of phylogenetic groups is related to the distribution and dispersal of tick vectors of the virus.

From July to October 2001, 215 cases of aseptic meningitis occurred among the inhabitants of the German city of Kassel and neighbouring counties. A matched case-control study identified bathing in a public, nature-like pond during the beginning of the outbreak as a risk factor for disease [matched odds ratio (mOR) 44·8, 95% confidence interval (CI) 3·9–515·6]. Among bathers, patients with meningitis spent more time in the water (mOR 18·8, 95% CI 2·0–174·1) and swallowed water more frequently (mOR=7·3, 95% CI 0·7–81·8). Of 30 cerebrospinal fluid samples tested, echovirus 30 was cultured from 16, and echovirus 13 from seven. An echovirus 30 sequence obtained from one pond water sample showed a 99% nucleotide and 100% amino-acid homology with patient isolates. This outbreak demonstrates the potential of nature-like swimming ponds to cause widespread community infection with substantial public health impact.

The aim of this study was to establish the relative importance of various risk factors for toxoplasmosis in a United Kingdom antenatal population. Toxoplasma immune status was determined by an immunoassay and linked to a questionnaire exploring dietary and environmental exposure to toxoplasmosis. The overall seroprevalence found was 9·1% (172/1897). A significantly higher seroprevalence was associated with rural location of the childhood home, childhood home in Europe excluding the United Kingdom, feeding a dog raw meat and increased age. A non-significant higher prevalence of toxoplasmosis was observed in women who had lived with a cat or kitten as a child. In contrast to recent European studies only weak associations between diet and toxoplasmosis were found. Gardening activity was not associated with seropositivity but a non-significant lower seroprevalence was seen in gardeners who always wore gloves. This study confirms that toxoplasma prevalence in the United Kingdom has continued to decline since the 1960s. The increasing seroprevalence with age found in this study, highlights the continuing need to educate women of childbearing age about the risk factors for toxoplasmosis.

This paper [1] is a milestone in the literature on infectious diseases. To put it in context, we recall that the late 19th century saw the construction of the germ theory, and its ultimate acceptance by the medical profession. The massive research effort led by Pasteur and Koch and their followers demonstrated a variety of infectious agents, catalogued their properties, and traced their pathogenesis in infected hosts. An understanding of the behaviour of infections in populations came only later, in the early 20th century, exemplified in the work of Ross on malaria [2], which was extrapolated to all infections in his ‘theory of happenings’ [3], and of Hamer on measles [4]. But there remained a tension between those who viewed infections from the perspective of the laboratory, with its emphasis upon biological properties, and those who viewed disease from the perspective of population statistics [5], which lent itself to more abstract and mathematical descriptions of epidemiological patterns. Fierce battles were waged between these disciplines, as between Almroth Wright and Karl Pearson on the subject of typhoid vaccination [6, 7].

A total of 162 clinical isolates of Shigella collected from children in a semi-rural community of Chile were examined for the presence of genetic determinants of resistance to ampicillin, chloramphenicol, tetracycline, and trimethoprim. Ampicillin resistance was most frequently associated with the presence of blaOXA in S. flexneri and with blaTEM in S. sonnei. The blaOXA gene but not blaTEM was located in class 1 integrons. The dhfrIa gene encoding for resistance to trimethoprim was associated to class 2 integrons and detected exclusively in S. flexneri, whereas dhfrIIIc was found in all S. sonnei strains and in 10% of the S. flexneri isolates. Cat, coding for choramphenicol resistance, and blaOXA genes were located in the chromosome in all cases, whereas tetA gene, coding for tetracycline resistance, and blaTEM, dhfrIa and dhfrIIIc genes were found either in the chromosome or in conjugative plasmids. Our results show a heterogenous distribution of antibiotic-resistance determinants between S. flexneri and S. sonnei.

Between August and October 2003, 15 cases of Legionnaires' disease were detected in the 9th district of Rome. To identify possible sources of Legionella exposure, a matched case-control study was conducted and environmental samples were collected. Hospital discharge records were also retrospectively analysed for the period July–November 2003, and results were compared with the same period during the previous 3 years. The case-control study revealed a significantly increased risk of disease among those frequenting a specific department store in the district (OR 9·8, 95% CI 2·1–46·0), and Legionella pneumophila was isolated from the store's cooling tower. Genotypic and phenotypic analysis of human and environmental isolates demonstrated that the cluster was caused by a single strain of L. pneumophila serogroup 1, and that the cooling tower of the store was the source of infection. The increased number of hospital admissions for microbiologically undiagnosed pneumonia during the study period may indicate that some legionellosis cases were not identified.

Congenital toxoplasmosis is rarely identified by routine clinical examination. The aim of this study was to estimate the incidence of the disease in the region of Ribeirão Preto, south-eastern Brazil. A definitive diagnosis was made on the basis of the persistence of anti-Toxoplasma IgG antibodies beyond 1 year of age. Blood samples obtained from 15162 neonates and adsorbed onto filter paper were tested for anti-Toxoplasma IgM antibodies. Fifteen samples gave positive results. A definitive diagnosis was confirmed in five of the 13 infants (38·5%) who completed follow-up. These five infants presented with serum IgM and/or IgA antibodies, and clinical abnormalities. Disease incidence was estimated to be 3·3/10000 (95% CI 1·0–7·7), indicating the need for preventive measures. Neonatal screening is feasible, but screening tests with a better performance are required; positive screening results must be carefully confirmed.

We did a seroepidemiological study to determine the circulating dengue virus serotypes and the extent to which the Singapore population has been exposed to multiple dengue virus serotypes, using the plaque reduction neutralization assay (PRNT). Of 164 enrolled subjects aged between 18–30 years, 49 subjects (29·8%) were PRNT positive for at least one dengue serotype. The seroprevalence was 39 (23·8%) for dengue virus serotype 1, 37 (22·6%) for type 2, 43 (26·2%) for type 3, and 30 (18·3%) for type 4. Of the 49 subjects with PRNT-positive dengue virus results, 28 (57·1%) were positive to all four virus serotypes, seven (14·3%) to three serotypes, two (4%) to two serotypes, and 12 (24·5%) to a single serotype. All four dengue virus serotypes circulate in Singapore, and a substantial proportion of the adult population in Singapore had exposure to more than one dengue virus serotype. In spite of multiple circulating types, the rate of dengue haemorrhagic fever is low in Singapore.

This study was undertaken to provide first-time estimates for the seroprevalence of parvovirus B19 infection among daycare educators in Montréal, Canada, and to identify factors associated with seropositivity. A cross-sectional design was used. Directors and educators from 81 daycare centres (DCCs) were surveyed about DCC and personal characteristics respectively, and serum samples from 477 female educators were tested for parvovirus B19 IgG antibodies. The seroprevalence of parvovirus B19 was 70%. Parvovirus B19 seropositivity was significantly associated with age and with working experience in DCCs, but the latter association was restricted to educators aged less than 40 years. In conclusion, working as a daycare educator appears to be associated with increased risk of acquiring parvovirus B19 infection, but this finding will require further investigation. Because of the large proportion of educators susceptible to acquiring parvovirus B19 infection, our findings also highlight the need for preventive measures.