Helicobacter pylori infection is typically acquired in early childhood, and a predominantly intrafamilial transmission has been postulated. To what extent family members share the same strains is poorly documented. Our aim was to explore patterns of shared strains within families by using molecular typing. Family members of H. pylori-infected 10-to 12-year-old index children identified in a school survey were invited to undergo gastroscopy. Bacterial isolates were typed with random amplified polymorphic DNA and PCRrestriction fragment length polymorphism of the genes ureA-B, glmM, or flaA. The presence or absence of the cag pathogenicity island, a bacterial virulence factor, was determined by PCR. GelCompar II software, supplemented with visual inspection, was used in the cluster analysis. In 39 families, 104 individuals contributed 208 bacterial isolates from the antrum and corpus. A large proportion, 29 of 36 (81%) of the offspring in a sibship, harbored the same strain as at least one sibling. Mother-offspring strain concordance was detected in 10 of 18 (56%) of the families. Of 17 investigated father-offspring relations in eight families, none were strain concordant. Spouses were infected with the same strains in 5 of 23 (22%) of the couples. Different strains in the antrum and corpus were found in 8 of 104 (8%) of the subjects. Our family-based fingerprinting study demonstrates a high proportion of shared strains among siblings. Transmission between spouses seems to be appreciable. The data support mother-child and sib-sib transmission as the primary transmission pathways of H. pylori.Helicobacter pylori colonizes half of the world's population, and the infection is associated with chronic gastritis, peptic ulcer, gastric cancer, and gastric lymphoma. In-depth knowledge of the transmission patterns may constitute important information for future intervention strategies.In the absence of consistent and verified environmental reservoirs, a predominantly person-to-person transmission has been postulated. H. pylori infection is associated with poor living conditions, and possible transmission routes are fecaloral, oral-oral, or gastro-oral, but firm evidence is lacking (36). The infection clusters in families and is usually acquired in early childhood. A child's risk of being infected is largely determined by the presence or absence of infected family members. Having an infected mother has been suggested to be a more prominent risk factor than having an infected father (30,35). Indications of sib-sib transmission have been reported (14). Transmission between spouses occurs but its significance is unclear (5, 9, 19).Molecular typing of pathogens can corroborate and further characterize the transmission pathways suggested by epidemiologic data based on infection status. Shared strains among individuals indicate person-to-person transmission or acquisition from a common source. Unrelated individuals harbor distinct H. pylori isolates (1), while clonal lineages can be discerned within families (2,7,11,16,20,22,24,2...

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Helicobacter pylori-associated diseases, such as peptic ulcer and gastric cancer, are common in Vietnam, but the prevalence of the infection is largely unknown. A validated enzyme-linked immunosorbent assay was used for seroepidemiology with 971 samples from the general population, ages 0 to 88 years, with 546 samples from an urban population (Hanoi), and with 425 samples from a poor, rural province (Hatay). The overall seroprevalence of the infection was 746 per 1,000, with a prevalence of 788 per 1,000 in Hanoi and 692 per 1,000 in Hatay (P ‫؍‬ 0.0007). The risk for infection in the rural area of Hatay was 40% lower than in the urban population of Hanoi, with the odds ratio being 0.59 (95% confidence interval, 0.43 to 0.81). The study shows that the prevalence of H. pylori infection is high in Vietnam and especially high in a large urban area, such as the city of Hanoi.Helicobacter pylori infection causes gastritis and peptic ulcer disease and is a cofactor in the development of gastric cancer (16). The prevalence of H. pylori infection is decreasing in developed countries but remains high in many developing countries (11). Data on the epidemiology of H. pylori infection in Vietnam are scarce, but peptic ulcer disease and gastric cancer represent major health problems. In a large survey, conducted at the Hanoi Military Hospital from 1963 to 1983, peptic ulcer was found by endoscopy in 7.8% of 300,000 volunteers, ages 18 to 60 years (19). Official statistics for the year 2001 indicate an age-standardized incidence of 77.26 per 100,000 person-years for gastric and duodenal ulcer disease (4). Gastric cancer is the second-most-common cancer form in men and the third most common in women, with an agestandardized incidence of 23.7 and 10.8 per 100,000 personyears in the year 2000, respectively (12) Seroepidemiological investigations represent the most rapid and convenient way of obtaining a picture of the prevalence of H. pylori infection in a population, but the assays used need to be validated in the population studied (6,10,14). Enzymelinked immunosorbent assay (ELISA) for immunoglobulin G (IgG) detection can be based either on whole-cell sonicate antigen or on one or several purified components of the bacterium as the antigen. A majority of serological studies are now conducted with commercial kits that have been evaluated in developed countries. These commercial kits are often too expensive for developing countries, and use of a validated inhouse ELISA assay based on sonicate antigens would seem preferable.We have previously evaluated with both Swedish and Vietnamese populations an in-house ELISA based on sonicated H. pylori antigen, supplemented with an absorption step with sonicated Campylobacter jejuni antigen to remove cross-reacting antibodies (2, 6, 15, 17). The studies showed that the local strains used for the H. pylori antigen give a better diagnostic performance and also that the cutoff level used for serodiagnosis in the general population needs to be adjusted (6, 17). The aim of the present study wa...

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Microbial exposure is necessary for the development of normal immune function, which has driven the idea of using probiotics for treatment and prevention of immune-mediated diseases in infancy and childhood. Mounting evidence indicates that probiotics have immunomodulatory effects. However, the mechanisms are still poorly understood. Specific antibody response is a valuable proxy for immune system maturation status in infancy. We aimed at determining the impact of Lactobacillus F19 (LF19) during weaning on infections and IgG antibody responses to routine vaccines. In a double-blind, placebo-controlled randomized intervention trial, infants were fed cereals with (n = 89) or without LF19 (n = 90) from 4 to 13 months of age. Infants were immunized with DTaP (diphtheria and tetanus toxoid and acellular pertussis), polio and Hib-conjugate vaccines at (3), 5(1/2) and 12 months of age. We assessed the number of days with infections, antibiotic prescriptions and antibody concentrations to Hib capsular polysaccharide (HibPS), diphtheria toxin (D) and tetanus toxoid (T) before and after the second and third doses. Days with infectious symptoms did not differ between the groups. Days with antibiotic prescriptions were fewer in the LF19 group (p = 0.044). LF19 enhanced anti-D concentrations when adjusting for breastfeeding duration and colonization with LF19 (p = 0.024). There was an interaction of the intervention and colonization with LF19 on anti-T concentrations during the course of vaccination (p = 0.035). The anti-HibPS concentrations were higher after the first and second dose of Hib vaccine in infants breastfed <6 months compared with those breastfed > or =6 months (p < 0.05), with no effect by LF19. In conclusion, feeding LF19 did not prevent infections, but increased the capacity to raise immune responses to protein antigens, with more pronounced effects in infants breastfed <6 months.

All three serological assays were equally informative. The very high sensitivity of the assays made it possible to characterize patients with different infection status. Elevated levels of specific anti-Pseudomonas antibodies showed to be the risk factor for developing chronic Pa infection. Due to the specificity of the tests, antibiotic treatment based on serology might be considered in selected cases. There is a window of opportunity for suppression and eradication of initial P. aeruginosa infection making measurement of specific anti-Pseudomonas antibodies helpful.

In order to investigate the possible role of Ixodes ricinus as a vector of zoonotic Babesia microti infection inEurope, a European rodent isolate (HK) and a zoonotic American isolate (GI) were studied in transmission experiments. PCR detected B. microti in the blood and spleens of infected gerbils (Meriones unguiculatus) and also in laboratory-induced infections of I. ricinus ticks. B. microti DNA was detected by PCR in all pooled samples of nymphs and the majority of adults that had fed as larvae and nymphs, respectively, on gerbils with acute infection of the European isolate, confirming that I. ricinus could serve as a vector in Europe. The American isolate, GI, proved to be equally infective for larval and nymphal I. ricinus as the HK strain, despite a very different appearance in gerbil erythrocytes. Nymphs infected with the HK and GI strains readily infected gerbils. In contrast to the finding in acute infections, ticks that fed on gerbils with chronic infections of HK and GI did not become infected. It was also found that the HK strain was not transmitted transovarially. The finding that a B. microti strain (GI) from a distant geographical region (United States) can infect and be transmitted by I. ricinus suggests that other European B. microti strains, in addition to the HK strain used here, are probably infective for I. ricinus, supporting the view that infection of humans with European B. microti may be a regular occurrence.Babesia microti is a tick-transmitted rodent blood parasite that was first reported as a cause of human disease in 1969 in the northeastern United States (23). Several hundred cases are now reported from this region each year (7). The disease is characterized by a gradual onset of malaise with anorexia, fever, headaches, myalgia, and other vague symptoms which may persist for long periods. Occasionally dangerous fulminating infections occur, particularly in immunocompromised or aged individuals. The vector is the tick Ixodes scapularis, and transmission is transstadial, the infection being acquired from mice (e.g., the white-footed mouse, Peromyscus leucopus) by larval or nymphal ticks and transmitted by nymphs or adults (5). Transovarial transmission, which occurs in other Babesia species, such as B. canis and B. bovis, has not been reported in B. microti (19).Babesia microti is also present throughout Europe, but no verified cases of human disease have been reported. This may be because the rodent tick Ixodes trianguliceps, implicated as the main vector in Europe (5, 7), does not bite humans. However, it has been shown that at least one European strain of B. microti may be transmitted by Ixodes ricinus (21), which is known to be a vector of several zoonotic diseases (4), and seroprevalence studies suggest that infection of humans with B. microti may occur in Europe (6, 9). In the present study, the infectivity for I. ricinus of a European strain and a zoonotic American strain of B. microti was investigated by PCR and by transmission to and from gerbils (Meriones unguiculatus). MAT...

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