Helicobacter pylori infection in Canadian and related Arctic Aboriginal populations

Increasing our knowledge about the epidemiology of Helicobacter pylori in Nunavik's Inuit population (Québec, Canada) using Qanuilirpitaa? 2017 cross-sectional survey

Helicobacter pylori is a bacterium that may colonise and proliferate in human stomachs, leading invariably to chronic inflammation and, to a lesser extent, to peptic ulcers and cancer. The main objective of this study is to describe the epidemiology surrounding H. pylori in Nunavik's Inuit population using the 2004 and 2017 Health Surveys. Estimated prevalences were 70.9% for bacterial colonisation using a stool antigens test (SAT), 72.5% for anti-H. pylori antibodies, 12.7% for faecal occult blood in participants aged ≥ 50 and respectively of 28.4%, 11.2% and 2.4% for a prior diagnosis of colonisation, gastritis and peptic ulcer in the medical charts, with under five cases of gastric cancer reported. Variables associated with higher SAT+ prevalence were the number of household members (prevalence ratio [PR] = 1.03) and age (quadratic relationship), whereas mainly drinking municipal (PR = 0.84) and natural water (PR = 0.72) compared to bottled water, and increasing alcohol consumption (PR = 0.96) were associated with reduced prevalence. Despite current regional guidelines targeting high risk individuals in the context of high prevalence, Nunavik's health authorities must remain vigilant by following gastric cancer incidence and the rapid evolution of guidelines, while considering local realities.

Helicobacter pylori exposure among the Awajún of the Peruvian Amazon: Prevalence and environmental, social, and biological associations

OBJECTIVES

Helicobacter pylori (H. pylori)-a gastric bacteria affecting almost 50% of the global population and leading to ulcers and cancer in severe cases-is a growing health concern among Indigenous populations who report a high burden of reported poor general health and gastrointestinal distress. We test hypothesized associations between H. pylori exposure patterns and environmental, social, and biological conditions among a sample of 212 Indigenous Awajún adults (112 males, 100 females, ages 18-65 years) living in the northern Peruvian Amazon.

MATERIALS AND METHODS

Dried blood spots were analyzed for H. pylori-specific IgG using a recently developed enzyme-linked immunosorbent assay. Resulting seropositivity rates and antibody concentrations, proxying past exposures to H. pylori were analyzed in relation to relevant environmental (toilet type, floor material, reported water quality), social (household size and education level), and biological (age, sex, BMI, blood pressure, immune and metabolic biomarkers) factors using multivariable regression analyses.

RESULTS

We found near ubiquitous seropositivity for H. pylori exposure in our sample (99.1% seropositive). In the regression analyses, elevations in H. pylori antibody concentrations were significantly higher among males compared to females (β = 0.36, p = 0.01). No associations were found with any other factors.

DISCUSSION

Anthropological research in the study communities suggests that the male bias in elevations of H. pylori antibody concentrations is related to cultural and biological factors. Future research is needed to further unravel these biocultural dynamics and determine whether elevations in H. pylori antibody concentrations have clinical relevance for gastrointestinal health outcomes in this population.

Human cold adaptation: An unfinished agenda v2.0

BACKGROUND

Research on human extreme cold climate adaptations has benefitted from a recent resurgence since Ted Steegmann laid out his Human Cold Adaptation Agenda in 2007. Human biologists have drastically expanded our knowledge in this area during the last 15 years, but we still have a great deal more work to do to fulfill the cold climate adaptation agenda.

METHODS

Here, I follow Steegmann's example by providing a review of cold climate adaptations and setting forth a new, expanded agenda.

RESULTS

I review the foundational work on cold climate adaptations including classic Bergmann, Allen, and Thomson rules as well as early work assessing metabolic differences among Indigenous cold climate populations. From there, I discuss some of the groundbreaking work currently taking place on cold climate adaptations such as brown adipose tissue (a heat generating organ), physical activity levels, metabolic rates, and behavioral/cultural mechanisms. Finally, I present a path forward for future research with a focus on some of the basic extreme cold adaptations as well as how human biologists should approach the effects of climate change on human health and well-being, particularly within a cold climate context.

CONCLUSION

The Arctic has felt the dramatic effects of climate change sooner and more acutely than other parts of the world, making it an ideal location for studying both cold climate adaptations and climate change resilience. Human biologists have a great deal to contribute to the conversation on not only adaptations to extreme cold, but also the ways in which climate change is being embodied by cold climate populations.

Changes in Gastric Pathology after H. pylori Treatment in Community-Driven Research Aimed at Gastric Cancer Prevention

Community-driven projects have characterized Helicobacter pylori (Hp) infection in Indigenous communities in the Northwest Territories (NT) and Yukon (YT), Canada. These projects address concerns about the frequent diagnosis of Hp infection among community members and its relation to gastric cancer deaths, perceived to occur with alarming frequency in this region. Projects included breath-test screening for Hp infection, gastroscopy with gastric biopsies, and treatment to eliminate Hp infection. Previous project results showed a high prevalence of stomach pathologies associated with increased cancer risk among Hp-positive participants at baseline. This analysis describes changes in precancerous gastric pathologies in project participants who had gastroscopy before baseline treatment during 2008-2013 and again in 2017. Throughout the study period, the same pathologist graded Hp density, active gastritis, chronic gastritis, atrophic gastritis, and intestinal metaplasia using the updated Sydney System. Of 310 participants from three communities with baseline pathology data, 69 had follow-up pathology data. Relative to baseline, the prevalence of Hp infection and precancerous gastric pathology was substantially lower at follow-up; most participants who were Hp-positive at baseline and Hp-negative at follow-up had reduced severity of active, chronic, and/or atrophic gastritis at follow-up. Though follow-up numbers are small, these results yield evidence that successful Hp treatment has the potential to reduce the risk of gastric cancer in Arctic Indigenous communities.

Helicobacter pylori in Native Americans in Northern Arizona

Background: In Arizona Helicobacter pylori prevalence of infection among Navajo adults is about 62% and gastric cancer incidence rate is 3–4 times higher than that of the non-Hispanic White population. Aim: The aim of this study was to estimate the prevalence of specific H. pylori virulence factors (cagA and vacA) among Navajo patients undergoing and their association with gastric disease. Methods: Virulence genes, cagA and vacA, in H. pylori were investigated in gastric biopsies from 96 Navajo patients over age 18 who were undergoing esophagogastroduodenoscopy. Biopsies from the antrum and fundus were used for molecular characterization to determine cagA type and number of EPIYA motifs and presence of alleles in the signal (s) and medium (m) regions of the vacA gene. Results: H. pylori infection was found in 22.9% of the biopsy samples. The cagA gene amplified in 57.6% of samples and showed a predominant “Western cagA” type, with the EPIYA-ABC motif (45.4%), most prevalent. The vacA allele s1bm1 was the most prevalent (54.5%). Conclusions: H. pylori genotypes were predominantly cagA Western-type and ABC EPIYA motifs. The vacA s1bm1 genotype was the most prevalent and seemed to be associated with gastritis. American Indian/Alaska Native populations are at higher risk for gastric cancer. It is important to identify genotypes of H. pylori and virulence factors involved in the high prevalence of H. pylori and associated disease among the Navajo population.

Climate Change and Enteric Infections in the Canadian Arctic: Do We Know What’s on the Horizon?

The Canadian Arctic has a long history with diarrheal disease, including outbreaks of campylobacteriosis, giardiasis, and salmonellosis. Due to climate change, the Canadian Arctic is experiencing rapid environmental transformation, which not only threatens the livelihood of local Indigenous Peoples, but also supports the spread, frequency, and intensity of enteric pathogen outbreaks. Advances in diagnostic testing and detection have brought to attention the current burden of disease due to Cryptosporidium, Campylobacter, and Helicobacter pylori. As climate change is known to influence pathogen transmission (e.g., food and water), Arctic communities need support in developing prevention and surveillance strategies that are culturally appropriate. This review aims to provide an overview of how climate change is currently and is expected to impact enteric pathogens in the Canadian Arctic.

Stomach Cancer Incidence and Mortality Trends among Circumpolar Nations

BACKGROUND

Stomach cancer incidence and mortality rates are declining across circumpolar nations, but the burden may not be distributed equally across subpopulations, including Indigenous peoples. Our objective was to examine stomach cancer incidence and mortality trends across circumpolar populations.

METHODS

Cancer incidence and mortality data from 1999-2016 were obtained from the Canadian Cancer Registry, Canadian Vital Statistics, CDC WONDER, NORDCAN, Northwestern Russian cancer registries, and National Cancer Reports. The direct method was used to calculate 10-year rolling age-standardized incidence and mortality rates to the world (WHO 2000-2025) and 2011 Canadian standard populations. Standardized incidence rate ratios (SRR) were calculated. Data were stratified by sex, year, and region. U.S. data were broken down by race [White; American Indian/Alaska Native (AIAN)]. Race data were not available from non-U.S. cancer registries.

RESULTS

Most populations showed declining incidence and mortality rates over time. Incidence rates among Greenland males and females, Alaska AIAN males and females, and Northern Canadian both sexes were elevated compared with regional counterparts and remained stable. The largest male SRR was observed among Alaska AIAN versus Alaska Whites [SRR = 3.82; 95% confidence interval (95% CI), 2.71-5.37]. The largest female SRR was observed among Alaska AIAN versus Alaska Whites (SRR = 4.10; 95% CI, 2.62-6.43).

CONCLUSIONS

Despite stomach cancer incidence and mortality rates declining overall, some northern and Indigenous populations experience elevated and stable incidence and mortality rates.

IMPACT

There is a need to address disparities observed among circumpolar subpopulations. Given similarities in incidence, mortality, and risk factor prevalence across circumpolar regions, addressing disparities could benefit from coordinated international action.

The Prevalence of Helicobacter pylori Infection in a Quaternary Hospital in Canada

Background

Helicobacter pylori (H. pylori) prevalence in Canada has been estimated to be around 20% to 30%. However, H. pylori prevalence is declining in industrialized countries. We conducted a retrospective study on a population of patients referred for esophagogastroduodenoscopy (EGD) in a Canadian quaternary hospital to see the current prevalence of H. pylori infection and identify its main risk factors.

Methods

We performed a retrospective cross-sectional study from the Electronic Medical Records of 500 patients who visited our endoscopy clinic and who had biopsies to search for H. pylori infection. In addition to the outcome of the biopsies, we collected demographic characteristics of patients, EGD indication and endoscopic findings.

Results

The overall prevalence of H. pylori was 13.0% (65/500) among our population. We found no association with age, sex, tobacco or alcohol consumption. However, we noticed a significantly higher prevalence of H. pylori among African (25.0%; 8/32), Asian (30.8%; 4/13) and South American (34.9%; 15/43) born subjects when compared to the Caucasian group (8.0%; 28/350) (all P < 0.05).

Conclusions

The prevalence of H. pylori in Canada is declining, particularly among its Caucasian population. The race seems to be the strongest risk factor associated with this infection.

Is the Utilization of Helicobacter pylori Stool Antigen Tests Appropriate in an Urban Canadian Population?

OBJECTIVES

Helicobacter pylori stool antigen test (HpSAT) appropriateness was investigated by assessing its testing and positivity rates in Calgary, Canada.

METHODS

The laboratory information system was accessed for all patients who received an HpSAT in 2018. Testing volume, test results, age, and sex of patients were collected. Sociodemographic risk factors and geospatial analysis were performed by matching laboratory data to the 2016 census data. Testing appropriateness was defined as a concordance between testing and positivity rates for each sociodemographic variable.

RESULTS

In 2018, 25,518 H pylori stool antigen tests were performed in Calgary, with an overall positivity rate of 14.7%. Geospatial mapping demonstrated significant distribution variations of testing and positivity rates of HpSAT in the city. Certain sociodemographic groups studied (eg, recent immigrants) appeared to be appropriately tested (testing rate relative risk [RR] = 2.26, positivity rate RR = 4.32; P < .0001), while other groups (eg, male) may have been undertested (testing rate RR = 0.85, positivity rate RR = 1.14; P < .0001).

CONCLUSIONS

Determining concordance of testing and positivity rate of a laboratory test can be used for assessing testing appropriateness for other diseases in other jurisdictions. This study demonstrated some at-risk patients may be missed for H pylori testing.

Burden of disease from Helicobacter pylori infection in western Canadian Arctic communities

Background

Indigenous communities across the circumpolar north have elevated H. pylori (Hp) prevalence and stomach cancer incidence. We aimed to describe the Hp-associated disease burden among western Canadian Arctic participants in community-driven projects that address concerns about health risks from Hp infection.

Methods

During 2008–2013, participants underwent Hp screening by urea breath test and gastroscopy with gastric biopsies. We estimated Hp prevalence and prevalence by Hp status of endoscopic and histopathologic diagnoses.

Results

Among 878 participants with Hp status data, Hp prevalence was: 62% overall; 66% in 740 Indigenous participants; 22% in 77 non-Indigenous participants (61 participants did not disclose ethnicity); 45% at 0–14 years old, 69% at 15–34 years old, and 61% at 35–96 years old. Among 309 participants examined endoscopically, visible mucosal lesions were more frequent in the stomach than the duodenum: the gastric to duodenal ratio was 2 for inflammation, 8 for erosions, and 3 for ulcers. Pathological examination in 308 participants with gastric biopsies revealed normal gastric mucosa in 1 of 224 Hp-positive participants and 77% (65/84) of Hp-negative participants with sharp contrasts in the prevalence of abnormalities between Hp-positive and Hp-negative participants, respectively: moderate-severe active gastritis in 50 and 0%; moderate-severe chronic gastritis in 91 and 1%; atrophic gastritis in 43 and 0%; intestinal metaplasia in 17 and 5%.

Conclusions

The observed pattern of disease is consistent with increased risk of stomach cancer and reflects substantial inequity in the Hp-associated disease burden in western Arctic Canadian hamlets relative to most North American settings. This research adds to evidence that demonstrates the need for interventions aimed at reducing health risks from Hp infection in Indigenous Arctic communities.

Chemical and microbial characteristics of municipal drinking water supply systems in the Canadian Arctic

Drinking water in the vast Arctic Canadian territory of Nunavut is sourced from surface water lakes or rivers and transferred to man-made or natural reservoirs. The raw water is at a minimum treated by chlorination and distributed to customers either by trucks delivering to a water storage tank inside buildings or through a piped distribution system. The objective of this study was to characterize the chemical and microbial drinking water quality from source to tap in three hamlets (Coral Harbour, Pond Inlet and Pangnirtung-each has a population of <2000) on trucked service, and in Iqaluit (population ~6700), which uses a combination of trucked and piped water conveyance. Generally, the source and drinking water was of satisfactory microbial quality, containing Escherichia coli levels of <1 MPN/100 mL with a few exceptions, and selected pathogenic bacteria and parasites were below detection limits using quantitative polymerase chain reaction (qPCR) methods. Tap water in households receiving trucked water contained less than the recommended 0.2 mg/L of free chlorine, while piped drinking water in Iqaluit complied with Health Canada guidelines for residual chlorine (i.e. >0.2 mg/L free chlorine). Some buildings in the four communities contained manganese (Mn), copper (Cu), iron (Fe) and/or lead (Pb) concentrations above Health Canada guideline values for the aesthetic (Mn, Cu and Fe) and health (Pb) objectives. Corrosion of components of the drinking water distribution system (household storage tanks, premise plumbing) could be contributing to Pb, Cu and Fe levels, as the source water in three of the four communities had low alkalinity. The results point to the need for robust disinfection, which may include secondary disinfection or point-of-use disinfection, to prevent microbial risks in drinking water tanks in buildings and ultimately at the tap.

Disinfection and removal of human pathogenic bacteria in arctic waste stabilization ponds

Wastewater stabilization ponds (WSPs) are commonly used to treat municipal wastewater in Arctic Canada. The biological treatment in the WSPs is strongly influenced by climatic conditions. Currently, there is limited information about the removal of fecal and pathogenic bacteria during the short cool summer treatment season. With relevance to public health, the objectives of this paper were to determine if treatment in arctic WSPs resulted in the disinfection (i.e., removal of fecal indicator bacteria, Escherichia coli) and removal of selected human bacterial pathogens from the treated effluent. The treatment performance, with focus on microbial removal, was assessed for the one-cell WSP in Pond Inlet (Nunavut [NU]) and two-cell WSP in Clyde River (NU) over three consecutive (2012-2014) summer treatment seasons (late June-early September). The WSPs provided a primary disinfection treatment of the wastewater with a 2-3 Log removal of generic indicator E. coli. The bacterial pathogens Salmonella spp., pathogenic E. coli, and Listeria monocytogenes, but not Campylobacter spp. and Helicobacter pylori, were detected in the untreated and treated wastewater, indicating that human pathogens were not reliably removed. Seasonal and annual variations in temperature significantly (p < 0.05) affected the disinfection efficiency. Improved disinfection and pathogen removal was observed for the two-cell system in Clyde River as compared to the one-cell system in Pond Inlet. A quantitative microbial risk assessment should be performed to determine if the release of low levels of human pathogens into the arctic environment poses a human health risk.

Prevalence of Helicobacter pylori among Alaskans: Factors associated with infection and comparison of urea breath test and anti-Helicobacter pylori IgG antibodies

BACKGROUND

Helicobacter pylori is one of the most common human infections in the world, and studies in Alaska Native people, as well as other Indigenous peoples, have shown a high prevalence of this gastric infection. This study was undertaken to determine the prevalence of H. pylori infection by urea breath test (UBT) and anti- H. pylori IgG among Alaskans living in four regions of the state and to identify factors associated with infection.

METHODS

A convenience sample of persons > 6 months old living in five rural and one urban Alaskan community were recruited from 1996 to 1997. Participants were asked about factors possibly associated with infection. Sera were collected and tested for anti- H. pylori IgG antibodies; a UBT was administered to participants > 5 years old.

RESULTS

We recruited 710 people of whom 571 (80%) were Alaska Native and 467 (66%) were from rural communities. Rural residents were more likely to be Alaska Native compared with urban residents (P < .001). Of the 710 people, 699 (98%) had a serum sample analyzed, and 634 (97%) persons > 5 years old had a UBT performed. H. pylori prevalence was 69% by UBT and 68% by anti- H. pylori IgG. Among those with a result for both tests, there was 94% concordance. Factors associated with H. pylori positivity were Alaska Native racial status, age ≥ 20 years, rural region of residence, living in a crowded home, and drinking water that was not piped or delivered.

CONCLUSIONS

Helicobacter pylori prevalence is high in Alaska, especially in Alaska Native persons and rural residents. Concordance between UBT and serology was also high in this group. Two socioeconomic factors, crowding and drinking water that was not piped or delivered, were found to be associated with H. pylori positivity.

Diagnosing water security in the rural North with an environmental security framework

This study explores the nature of water security challenges in rural Alaska, using a framework for environmental security that entails four interrelated concepts: availability, access, utility, and stability of water resources. Many researchers and professionals agree that water insecurity is a problem in rural Alaska, although the scale and nature of the problem is contested. Some academics have argued that the problem is systemic, and rooted in an approach to water security by the state that prioritizes economic concerns over public health concerns. Health practitioners and state agencies, on the other hand, contend that much progress has been made, and that nearly all rural households have access to safe drinking water, though many are still lacking 'modern' in-home water service. Here, we draw on a synthesis of ethnographic research alongside data from state agencies to show that the persistent water insecurity problems in rural Alaska are not a problem of access to or availability of clean water, or a lack of 'modern' infrastructure, but instead are rooted in complex human dimensions of water resources management, including the political legacies of state and federal community development schemes that did not fully account for local needs and challenges. The diagnostic approach we implement here helps to identify solutions to these challenges, which accordingly focus on place-based needs and empowering local actors. The framework likewise proves to be broadly applicable to exploring water security concerns elsewhere in the world.

The contribution of Helicobacter pylori to excess gastric cancer in Indigenous and Pacific men: a birth cohort estimate

BACKGROUND

The reasons for higher gastric cancer incidence rates in indigenous populations are debated.

METHODS

We quantify the role of Helicobacter pylori in excess gastric cancer incidence in Māori and Pacific men in New Zealand. Age-standardized gastric cancer rate ratios for 1981-2004 were calculated in Māori and Pacific men compared with European/other men born in 1926-1940 and in 1941-1955. Rate ratios were then compared with those restricted to H. pylori prevalent populations.

RESULTS

H. pylori contributed substantially to excess gastric cancer incidence in Māori men (50%, 61%) and Pacific men (71%, 82%) in both cohorts.

CONCLUSIONS

Policy should focus on reducing the acquisition and prevalence of H. pylori infection in these populations.

Population Knowledge, Attitude, and Practice Regarding Helicobacter pylori Transmission and Outcomes: A Literature Review

BACKGROUND

Helicobacter pylori infection is associated with the development of chronic gastritis, peptic ulcer disease, and gastric cancer. Current clinical recommendations are that H. pylori test-and-treat should be individualized based on comorbidities and patient preferences among populations at increased risk for certain morbidities. However, knowledge, attitudes and practices regarding H. pylori among potential patient populations are largely unknown.

MATERIALS

We conducted a literature review to assess knowledge, attitudes, and practices of patients or community populations around H. pylori transmission, prevention, and associated morbidity.

RESULTS

Nine studies met the inclusion criteria, all published between 1997 and 2014. Eight studies evaluated perception of H. pylori among at-risk populations, while one study evaluated perception among a general population. The studies suggest inconsistencies between the perceptions of these populations and the established understanding of knowledge, attitude, and preventive practices for H. pylori among even at-risk populations.

CONCLUSION

To adequately respond to current test-and-treat recommendations for treatment of H. pylori, general population education must be implemented, especially among at-risk populations. Further work is needed within at-risk populations in the United States to determine prevalence of H. pylori and their current knowledge if adequate prevention strategies are to be designed.

ACG Clinical Guideline: Treatment of Helicobacter pylori Infection

Helicobacter pylori (H. pylori) infection is a common worldwide infection that is an important cause of peptic ulcer disease and gastric cancer. H. pylori may also have a role in uninvestigated and functional dyspepsia, ulcer risk in patients taking low-dose aspirin or starting therapy with a non-steroidal anti-inflammatory medication, unexplained iron deficiency anemia, and idiopathic thrombocytopenic purpura. While choosing a treatment regimen for H. pylori, patients should be asked about previous antibiotic exposure and this information should be incorporated into the decision-making process. For first-line treatment, clarithromycin triple therapy should be confined to patients with no previous history of macrolide exposure who reside in areas where clarithromycin resistance amongst H. pylori isolates is known to be low. Most patients will be better served by first-line treatment with bismuth quadruple therapy or concomitant therapy consisting of a PPI, clarithromycin, amoxicillin, and metronidazole. When first-line therapy fails, a salvage regimen should avoid antibiotics that were previously used. If a patient received a first-line treatment containing clarithromycin, bismuth quadruple therapy or levofloxacin salvage regimens are the preferred treatment options. If a patient received first-line bismuth quadruple therapy, clarithromycin or levofloxacin-containing salvage regimens are the preferred treatment options. Details regarding the drugs, doses and durations of the recommended and suggested first-line and salvage regimens can be found in the guideline.

The diagnosis and treatment of Helicobacter pylori infection in Arctic regions with a high prevalence of infection: Expert Commentary

Helicobacter pylori infection is a major cause of peptic ulcer and is also associated with chronic gastritis, mucosa-associated lymphoid tissue (MALT) lymphoma, and adenocarcinoma of the stomach. Guidelines have been developed in the United States and Europe (areas with low prevalence) for the diagnosis and management of this infection, including the recommendation to 'test and treat' those with dyspepsia. A group of international experts performed a targeted literature review and formulated an expert opinion for evidenced-based benefits and harms for screening and treatment of H. pylori in high-prevalence countries. They concluded that in Arctic countries where H. pylori prevalence exceeds 60%, treatment of persons with H. pylori infection should be limited only to instances where there is strong evidence of direct benefit in reduction of morbidity and mortality, associated peptic ulcer disease and MALT lymphoma and that the test-and-treat strategy may not be beneficial for those with dyspepsia.

Complete Genome Sequences of Two Helicobacter pylori Strains from a Canadian Arctic Aboriginal Community

We report here the complete genome sequences of two Amerind Helicobacter pylori strains from Aklavik, Northwest Territories, Canada. One strain contains extra iron-cofactored urease genes and ~140 rearrangements in its chromosome relative to other described strains (typically differing from one another by <10 rearrangements), suggesting that it represents a novel lineage of H. pylori.

Germline mutations in MAP3K6 are associated with familial gastric cancer

Gastric cancer is among the leading causes of cancer-related deaths worldwide. While heritable forms of gastric cancer are relatively rare, identifying the genes responsible for such cases can inform diagnosis and treatment for both hereditary and sporadic cases of gastric cancer. Mutations in the E-cadherin gene, CDH1, account for 40% of the most common form of familial gastric cancer (FGC), hereditary diffuse gastric cancer (HDGC). The genes responsible for the remaining forms of FGC are currently unknown. Here we examined a large family from Maritime Canada with FGC without CDH1 mutations, and identified a germline coding variant (p.P946L) in mitogen-activated protein kinase kinase kinase 6 (MAP3K6). Based on conservation, predicted pathogenicity and a known role of the gene in cancer predisposition, MAP3K6 was considered a strong candidate and was investigated further. Screening of an additional 115 unrelated individuals with non-CDH1 FGC identified the p.P946L MAP3K6 variant, as well as four additional coding variants in MAP3K6 (p.F849Sfs*142, p.P958T, p.D200Y and p.V207G). A somatic second-hit variant (p.H506Y) was present in DNA obtained from one of the tumor specimens, and evidence of DNA hypermethylation within the MAP3K6 gene was observed in DNA from the tumor of another affected individual. These findings, together with previous evidence from mouse models that MAP3K6 acts as a tumor suppressor, and studies showing the presence of somatic mutations in MAP3K6 in non-hereditary gastric cancers and gastric cancer cell lines, point towards MAP3K6 variants as a predisposing factor for FGC.

The underlying genetic mutations involved in 60% of inherited gastric cancer cases remain unknown. Here we present a large, extended pedigree with familial gastric cancer and an association in part of the family with a mutation in MAP3K6. The conservation, predicted pathogenicity of the variant, tissue distribution, and known function of MAP3K6 made this a strong candidate that warranted further investigation. Examination of an additional 115 unrelated probands identified additional mutations in MAP3K6, including a truncating mutation.

A randomized controlled trial comparing sequential with triple therapy for Helicobacter pylori in an Aboriginal community in the Canadian North

BACKGROUND

Helicobacter pylori infection occurs more frequently in Arctic Aboriginal settings than elsewhere in North America and Europe. Research aimed at reducing health risks from H pylori infection has been conducted in the Aboriginal community of Aklavik, Northwest Territories.

OBJECTIVE

To compare the effectiveness of the Canadian standard therapy with an alternative therapy for eliminating H pylori infection in Aklavik.

METHODS

Treatment-naive H pylori-positive individuals were randomly assigned to a 10-day regimen (oral twice-daily doses) with rabeprazole (20 mg): standard triple therapy (proton pump inhibitor, added clarithromycin [500 mg] and amoxicillin [1 g] [PPI-CA]); sequential therapy (ST) added amoxicillin (1 g) on days 1 to 5, and metronidazole (500 mg) and clarithromycin (500 mg) on days 6 to 10. Participants with clarithromycin-resistant H pylori were randomly assigned to ST or quadruple therapy. Treatment effectiveness was estimated as per cent (95% CI) with a negative urea breath test at least 10 weeks after treatment.

RESULTS

Of 104 (53 PPI-CA, 51 ST) randomized participants, 89 (49 PPI-CA, 40 ST) had post-treatment results. Per-protocol treatment effectiveness was 59% (95% CI 45% to 73%) for PPI-CA and 73% (95% CI 58% to 87%) for ST. Based on intention to treat, effectiveness was 55% (95% CI 41% to 69%) for PPI-CA and 57% (95% CI 43% to 71%) for ST. Of 77 participants (43 PPI-CA, 34 ST) with 100% adherence, effectiveness was 63% (95% CI 43% to 82%) for PPI-CA and 81% (95% CI 63% to 99%) for ST.

CONCLUSIONS

While additional evidence is needed to confirm that ST is more effective for Arctic Aboriginal communities than the Canadian standard H pylori treatment, these results show standard PPI-CA treatment to be inadequate for communities such as Aklavik.

Ethics and Community Involvement in Syntheses Concerning American Indian, Alaska Native, or Native Hawaiian Health: A Systematic Review

BACKGROUND

The objective of the research was to review reporting of ethical concerns and community involvement in peer-reviewed systematic reviews or meta-analyses concerning American Indian, Alaska Native, or Native Hawaiian (AI/AN/NH) health.

METHODS

Text words and indexed vocabulary terms were used to query PubMed, Embase, Cochrane Library, and the Native Health Database for systematic reviews or meta-analyses concerning AI/AN/NH health published in peer-reviewed journals, followed by a search through reference lists. Each article was abstracted by two independent reviewers; results were discussed until consensus was reached.

RESULTS

We identified 107 papers published from 1986-2012 that were primarily about AI/AN/NH health or presented findings separately for AI/AN/NH communities. Two reported seeking indigenous reviewer feedback; none reported seeking input from tribes and communities. Approximately 7% reported on institutional review board (IRB) approval of included studies, 5% reported on tribal approval, and 4% referenced the sovereignty of AI/AN tribes. Approximately 63% used evidence from more than one AI/AN/NH population study, and 28% discussed potential benefits to communities from the synthesis research.

CONCLUSIONS

Reporting of ethics and community involvement are not prominent. Systematic reviews and meta-analyses making community-level inferences may pose risks to communities. Future systematic reviews and meta-analyses should consider ethical and participatory dimensions of research.

Municipal water quantities and health in Nunavut households: an exploratory case study in Coral Harbour, Nunavut, Canada

Background

Access to adequate quantities of water has a protective effect on human health and well-being. Despite this, public health research and interventions are frequently focused solely on water quality, and international standards for domestic water supply minimums are often overlooked or unspecified. This trend is evident in Inuit and other Arctic communities even though numerous transmissible diseases and bacterium infections associated with inadequate domestic water quantities are prevalent.

Objectives

Our objective was to explore the pathways by which the trucked water distribution systems being used in remote northern communities are impacting health at the household level, with consideration given to the underlying social and environmental determinants shaping health in the region.

Methods

Using a qualitative case study design, we conducted 37 interviews (28 residents, 9 key informants) and a review of government water documents to investigate water usage practices and perspectives. These data were thematically analysed to understand potential health risks in Arctic communities and households.

Results

Each resident receives an average of 110 litres of municipal water per day. Fifteen of 28 households reported experiencing water shortages at least once per month. Of those 15, most were larger households (5 people or more) with standard sized water storage tanks. Water shortages and service interruptions limit the ability of some households to adhere to public health advice. The households most resilient, or able to cope with domestic water supply shortages, were those capable of retrieving their own drinking water directly from lake and river sources. Residents with extended family and neighbours, whom they can rely on during shortages, were also less vulnerable to municipal water delays.

Conclusions

The relatively low in-home water quantities observed in Coral Harbour, Nunavut, appear adequate for some families. Those living in overcrowded households, however, are accessing water in quantities more typically seen in water insecure developing countries. We recommend several practical interventions and revisions to municipal water supply systems.

Weather and livestock risk factors for Escherichia coli O157 human infection in Alberta, Canada

This study investigated the extent to which proximity to cattle and weather events in Alberta predispose human populations to E. coli O157 disease. Cases of human E. coli O157 infection in Alberta between 2004 and 2011 were obtained from the province's Communicable Disease Reporting System and Discharge Abstract Database. Regression models based on spatial area incorporated human infection data with livestock and weather covariates. A variety of regression models were applied (i.e. least squares, spatial lag/error, Poisson, negative binomial) to test the most appropriate approach. Ratios for the total number of calves, bulls and beef cows to human population were highlighted as significant cattle density variables in all final best-fitting models. Weather variables were not significant in final regression models averaged over the full study period. Our results provide evidence of a significant association between measures of cattle density and human E. coli O157 disease in Alberta.

Disease manifestations of Helicobacter pylori infection in Arctic Canada: using epidemiology to address community concerns

OBJECTIVES

Helicobacter pylori infection, linked to gastric cancer, is responsible for a large worldwide disease burden. H pylori prevalence and gastric cancer rates are elevated among indigenous Arctic communities, but implementation of prevention strategies is hampered by insufficient information. Some communities in northern Canada have advocated for H pylori prevention research. As a first step, community-driven research was undertaken to describe the H pylori-associated disease burden in concerned communities.

DESIGN

Participants in this cross-sectional study completed a clinical interview and gastroscopy with gastric biopsies taken for histopathological examination in February 2008.

SETTING

Study procedures were carried out at the health centre in Aklavik, Northwest Territories, Canada (population ∼600).

PARTICIPANTS

All residents of Aklavik were invited to complete a clinical interview and gastroscopy; 194 (58% female participants; 91% Aboriginal; age range 10-80 years) completed gastroscopy and had gastric biopsies taken.

PRIMARY AND SECONDARY OUTCOME MEASURES

This analysis estimates the prevalence of gastric abnormalities detected by endoscopy and histopathology, and associations of demographic and clinical variables with H pylori prevalence.

RESULTS

Among 194 participants with evaluable gastric biopsies, 66% were H pylori-positive on histology. Among H pylori-positive participants, prevalence was 94% for acute gastritis, 100% for chronic gastritis, 21% for gastric atrophy and 11% for intestinal metaplasia of the gastric mucosa, while chronic inflammation severity was mild in 9%, moderate in 47% and severe in 43%. In a multivariable model, H pylori prevalence was inversely associated with previous gastroscopy, previous H pylori therapy and aspirin use, and was positively associated with alcohol consumption.

CONCLUSIONS

In this population, H pylori-associated gastric histopathology shows a pattern compatible with elevated risk of gastric cancer. These findings demonstrate that local concern about health risks from H pylori is warranted and provide an example of how epidemiological research can address health priorities identified by communities.

The burden of stomach cancer in indigenous populations: a systematic review and global assessment

OBJECTIVE

Stomach cancer is a leading cause of cancer death, especially in developing countries. Incidence has been associated with poverty and is also reported to disproportionately affect indigenous peoples, many of whom live in poor socioeconomic circumstances and experience lower standards of health. In this comprehensive assessment, we explore the burden of stomach cancer among indigenous peoples globally.

DESIGN

The literature was searched systematically for studies on stomach cancer incidence, mortality and survival in indigenous populations, including Indigenous Australians, Maori in New Zealand, indigenous peoples from the circumpolar region, native Americans and Alaska natives in the USA, and the Mapuche peoples in Chile. Data from the New Zealand Health Information Service and the Surveillance Epidemiology and End Results (SEER) Program were used to estimate trends in incidence.

RESULTS

Elevated rates of stomach cancer incidence and mortality were found in almost all indigenous peoples relative to corresponding non-indigenous populations in the same regions or countries. This was particularly evident among Inuit residing in the circumpolar region (standardised incidence ratios (SIR) males: 3.9, females: 3.6) and in Maori (SIR males: 2.2, females: 3.2). Increasing trends in incidence were found for some groups.

CONCLUSIONS

We found a higher burden of stomach cancer in indigenous populations globally, and rising incidence in some indigenous groups, in stark contrast to the decreasing global trends. This is of major public health concern requiring close surveillance and further research of potential risk factors. Given evidence that improving nutrition and housing sanitation, and Helicobacter pylori eradication programmes could reduce stomach cancer rates, policies which address these initiatives could reduce inequalities in stomach cancer burden for indigenous peoples.

Adherence and barriers to H. pylori treatment in Arctic Canada

Introduction

Helicobacter pylori infection is an emerging health concern to some northern Canadian Aboriginal communities and their clinicians. Clinicians in the north perceive H. pylori infection to be a major clinical problem because they find H. pylori infection in many patients evaluated for common stomach complaints, leading to frequent demand for treatment, which often fails. Moreover, public health authorities identified the need for information to develop locally appropriate H. pylori control strategies. We described adherence and identified barriers to completing treatment among H. pylori-positive participants in a community-based project inspired by local concerns about H. pylori infection risks.

Methods

In 2008, 110 H. pylori-positive participants (diagnosed by a breath test, histopathology and/or culture) of the Aklavik H. pylori project were randomised to standard-of-care or sequential treatment. We ascertained adherence by interviewing participants using a structured questionnaire. We estimated adherence frequencies as the proportion of participants who reported taking either 100% of doses (perfect adherence) or ≥80% of doses (good adherence). To compare the proportion with perfect or good adherence in subgroups, we report proportion differences and 95% confidence intervals (CI).

Results

Of 87 participants who were interviewed, 64% reported perfect adherence and 80% reported good adherence. We observed more frequent perfect adherence for: standard therapy (67%) versus sequential (62%); males (76%) versus females (52%); participants 40–77 years (79%) versus 17–39 (50%). Proportion differences were 5% (CI: −15, 25) for standard versus sequential therapy; 23% (CI: 4, 43) for male versus female; and 29% (CI: 10, 48) for 40–77 versus 15–39 years for perfect adherence. Of the 29 participants who reported poor adherence (<80% of doses taken), the following barriers to treatment were reported: changed mind about taking treatment (24%), consumption of alcoholic beverages (18%), nausea (18%), forgetfulness (12%), stomach pain (12%), difficulty in swallowing pills (6%), no reason (6%) or bad taste of the pills (6%).

Conclusion

This analysis suggests that adherence to treatment for eliminating H. pyori infection may vary by regimen and may be influenced by socio-demographic factors. These findings add to the small body of evidence pertaining to adherence to H. pylori treatment in Arctic Aboriginal communities. On-going research in additional northern Canadian communities will accumulate data for developing recommendations to improve adherence for treatment to eliminate H. pylori infection.

The potential of dextran-based glycoconjugates for development of Helicobacter pylori vaccine

We have recently demonstrated that synthetic glycoconjugates based on delipidated lipopolysaccharide (LPS) of Helicobacter pylori and containing an α(1-6)-glucan chain induced broadly cross-reactive functional antibodies in immunized animals. To investigate the candidacy of α(1-6)-glucan as an alternative vaccine strategy we prepared glycoconjugates based on dextrans produced by lactic acid bacteria Leuconostoc mesenteroides B512F and consisting of linear α(1-6)-glucan chains with limited branching. Three dextrans with averaged molecular masses of 5,000 Da, 3,500 Da and 1,500 Da, respectively, were modified with a diamino group-containing linker and conjugated to a carrier protein, tetanus toxoid (TT) or diphtheria toxoid (DT), and their immunological properties investigated. The conjugates were immunogenic in both rabbits and mice and induced specific IgG responses against α(1-6)-glucan-expressing H. pylori LPS. Studies performed with post-immune sera of mice and rabbits immunized with dextran-based conjugates demonstrated cross-reactivity with LPS from typeable and non-typeable strains of H. pylori and selected mutants. The post-immune sera from rabbits that received the conjugates exhibited functional activity against α(1-6)-glucan-positive strains of H. pylori. These data provide evidence that dextran-based conjugates may offer a simplified approach to the development of carbohydrate-based vaccines against H. pylori.

Challenges in conducting community-driven research created by differing ways of talking and thinking about science: a researcher's perspective

Increasingly, health scientists are becoming aware that research collaborations that include community partnerships can be an effective way to broaden the scope and enhance the impact of research aimed at improving public health. Such collaborations extend the reach of academic scientists by integrating a variety of perspectives and thus strengthening the applicability of the research. Communication challenges can arise, however, when attempting to address specific research questions in these collaborations. In particular, inconsistencies can exist between scientists and community members in the use and interpretation of words and other language features, particularly when conducting research with a biomedical component. Additional challenges arise from differing perceptions of the investigative process. There may be divergent perceptions about how research questions should and can be answered, and in expectations about requirements of research institutions and research timelines. From these differences, misunderstandings can occur about how the results will ultimately impact the community. These communication issues are particularly challenging when scientists and community members are from different ethnic and linguistic backgrounds that may widen the gap between ways of talking and thinking about science, further complicating the interactions and exchanges that are essential for effective joint research efforts. Community-driven research that aims to describe the burden of disease associated with Helicobacter pylori infection is currently underway in northern Aboriginal communities located in the Yukon and Northwest Territories, Canada, with the goal of identifying effective public health strategies for reducing health risks from this infection. This research links community representatives, faculty from various disciplines at the University of Alberta, as well as territorial health care practitioners and officials. This highly collaborative work will be used to illustrate, from a researcher's perspective, some of the challenges of conducting public health research in teams comprising members with varying backgrounds. The consequences of these challenges will be outlined, and potential solutions will be offered.

Helicobacter pylori incidence and re-infection in the Aklavik H. pylori Project

Background

The Aklavik H. pylori Project (AHPP) (www.canhelpworkinggroup.ca) is a community-driven project examining Helicobacter pylori infection and its influence on health in a diverse Aboriginal community in the Northwest Territories. Initial research revealed that 58% of 333 participants who underwent a urea breath test (UBT) between 2007 and 2010 were H. pylori-positive. From 2008 to 2010, we offered treatment to H. pylori-positive participants and 113 consented to this treatment.

Objective

We estimated H. pylori incidence in AHPP participants who initially tested negative and the re-infection frequency in initially positive participants who were successfully treated to clear the infection.

Methods

Participants who were initially H. pylori-negative or negative after treatment during 2008–2010 were eligible for inclusion. From November 2011 to June 2012, participants were offered a UBT and the samples were analyzed using infrared spectroscopy (IRIS). Participants with a positive test result were classified as new cases for estimating incidence among participants testing negative at baseline and re-infection among those successfully treated for H. pylori infection.

Results

Among 38 initially negative participants, follow-up UBT showed that 33 remained negative, 3 were positive, and 2 had uncertain status. The estimated incidence proportion during the follow-up period was 8.3% (95% CI: 1.8–22.0%). Among 43 participants with a negative post-treatment UBT, 41 remained negative and 2 were positive. The estimated re-infection proportion during the follow-up period was 4.7% (95% CI: 0.6–16.0%). The frequency of new cases was similar in males and females. Aboriginal participants had a combined re-infection/incidence rate of 2.4% per year (95% CI: 0.8–5.9% per year). All 9 non-Aboriginal participants remained free from infection throughout the study period, as did all 23 participants aged 55 years and above.

Conclusions

The AHPP has substantially reduced the burden of infection in Aklavik since 2008. Continued monitoring, treatment, community engagement and knowledge translation activities are needed to ensure a lasting benefit of the project.

Prevalence of Helicobacter pylori in a First Nations population in northwestern Ontario

OBJECTIVE

To assess prevalence of Helicobacter pylori infection, reasons for referral for gastroscopy, and clinical findings of gastroscopy in a symptomatic First Nations population in northwestern Ontario from 2009 to 2011.

DESIGN

Three hundred four hospital charts of symptomatic patients who underwent upper endoscopy between June 2009 and March 2011 were reviewed.

SETTING

Meno Ya Win Health Centre in Sioux Lookout, Ont.

PARTICIPANTS

First Nations patients with dyspepsia undergoing gastroscopy.

MAIN OUTCOME MEASURES

Reason for referral, and clinical and histologic findings on gastroscopy.

RESULTS

The most common reasons for referral for gastroscopy were dyspepsia (59.2%) and undiagnosed anemia (18.1%). Overall, 66.8% of patients underwent biopsies; 37.9% of these patients tested positive for H pylori. Gastritis was encountered the most often, in 46.1% of patients; gastric ulcers in 6.9% of patients; and normal gastric mucosa was seen 36.8% of the time. The rate of H pylori infection is higher than in urban Canadian populations, but lower than in previous aboriginal prevalence estimates, particularly those based on seroprevalence values.

CONCLUSION

This study raises the clinical question of how eradication testing and treatment protocols should be addressed in remote regions with high disease prevalence. As more is learned about the role H pylori infection plays in serious gastrointestinal diseases, rural and aboriginal populations might need a special focus on testing availability and treatment close to home.

Indigenous populations health protection: a Canadian perspective

The disproportionate effects of the 2009 H1N1 pandemic on many Canadian Aboriginal communities have drawn attention to the vulnerability of these communities in terms of health outcomes in the face of emerging and reemerging infectious diseases. Exploring the particular challenges facing these communities is essential to improving public health planning. In alignment with the objectives of the Pandemic Influenza Outbreak Research Modelling (Pan-InfORM) team, a Canadian public health workshop was held at the Centre for Disease Modelling (CDM) to: (i) evaluate post-pandemic research findings; (ii) identify existing gaps in knowledge that have yet to be addressed through ongoing research and collaborative activities; and (iii) build upon existing partnerships within the research community to forge new collaborative links with Aboriginal health organizations. The workshop achieved its objectives in identifying main research findings and emerging information post pandemic, and highlighting key challenges that pose significant impediments to the health protection and promotion of Canadian Aboriginal populations. The health challenges faced by Canadian indigenous populations are unique and complex, and can only be addressed through active engagement with affected communities. The academic research community will need to develop a new interdisciplinary framework, building upon concepts from 'Communities of Practice', to ensure that the research priorities are identified and targeted, and the outcomes are translated into the context of community health to improve policy and practice.

Why are East Asians more susceptible to several infection-associated cancers (carcinomas of the nasopharynx, stomach, liver, adenocarcinoma of the lung, nasal NK/T-cell lymphomas)?

There are at least five cancers with uniquely high incidence amongst East and Southeast Asian ethnic groups - namely nasopharyngeal carcinoma (NPC); gastric carcinoma; hepatocellular carcinoma (HCC); adeno-carcinoma of the lung in female non-smokers and nasal NK/T-cell lymphomas. They all appear to be related to an infective cause (Epstein Barr Virus, Helicobacter pylori, hepatitis B virus). We hypothesize that a genetic bottleneck 30,000years ago at the Last Glacial Maximum could have resulted in unique genetic polymorphisms in Toll-like receptor 8, making East Asians more vulnerable to these infective associated cancers. This bottleneck could have been caused by the presence of malaria in the southern Himalayan conduit between central and East Asia; and only those with an attenuated innate immune response to the malarial parasite (perhaps reflected by the TLR8 polymorphism) were spared the ravages of cerebral malaria; allowing these people to cross into east Asia, but then rendering them susceptible to later endemic infections and their associated cancers.

Challenges created by data dissemination and access restrictions when attempting to address community concerns: individual privacy versus public wellbeing

BACKGROUND

Population health data are vital for the identification of public health problems and the development of public health strategies. Challenges arise when attempts are made to disseminate or access anonymised data that are deemed to be potentially identifiable. In these situations, there is debate about whether the protection of an individual's privacy outweighs potentially beneficial public health initiatives developed using potentially identifiable information. While these issues have an impact at planning and policy levels, they pose a particular dilemma when attempting to examine and address community concerns about a specific health problem.

METHODS

Research currently underway in northern Canadian communities on the frequency of Helicobacter pylori infection and associated diseases, such as stomach cancer, is used in this article to illustrate the challenges that data controls create on the ability of researchers and health officials to address community concerns.

RESULTS

Barriers are faced by public health professionals and researchers when endeavouring to address community concerns; specifically, provincial cancer surveillance departments and community-driven participatory research groups face challenges related to data release or access that inhibit their ability to effectively address community enquiries. The resulting consequences include a limited ability to address misinformation or to alleviate concerns when dealing with health problems in small communities.

CONCLUSIONS

The development of communication tools and building of trusting relationships are essential components of a successful investigation into community health concerns. It may also be important to consider that public wellbeing may outweigh the value of individual privacy in these situations. As such, a re-evaluation of data disclosure policies that are applicable in these circumstances should be considered.

Helicobacter pylori in First Nations and recent immigrant populations in Canada

The diminishing prevalence of Helicobacter pylori infection among most segments of the Canadian population has led to changes in the etiologies and patterns of associated upper gastrointestinal diseases, including fewer peptic ulcers and their complications. Canadian Aboriginals and recent immigrants are among populations in which the prevalence of H pylori infection remains high and, therefore, the health risks imposed by H pylori remain a significant concern. Population-based strategies for H pylori eradication in groups with a low prevalence of infection are unlikely to be cost effective, but such measures are attractive in groups in which the prevalence rates of infection remain substantial. In addition to a lower prevalence of peptic ulcers and dyspepsia, the public health value of eradication may be particularly important if this leads to a reduction in the prevalence of gastric cancer in high prevalence groups. Therefore The Canadian Helicobacter Study Group held a conference that brought together experts in the field to address these issues, the results of which are reviewed in the present article. Canadians with the highest prevalence of H pylori infection are an appropriate focus for considering the health advantages of eradicating persistent infection. In Canadian communities with a high prevalence of both H pylori and gastric cancer, there remains an opportunity to test the hypothesis that H pylori infection is a treatable risk factor for malignancy.

Burden of anemia among indigenous populations

An international perspective of the magnitude of anemia in indigenous peoples is currently lacking. The present systematic review was performed to characterize the global prevalence, severity, and etiology of anemia in indigenous peoples by conducting a systematic search of original research published in English from 1996 to February 2010 using PubMed, Medline, and Embase. A total of 50 studies, representing the following 13 countries, met the inclusion criteria: Australia, Brazil, Canada, Guatemala, India, Kenya, Malaysia, Mexico, New Zealand, Sri Lanka, Tanzania, the United States, and Venezuela. Results indicate major deficiencies in the coverage and quality of anemia monitoring data for indigenous populations worldwide. The burden of anemia is overwhelmingly higher among indigenous groups compared to the general population and represents a moderate (20-39.9%) to severe (≥40%) public health problem. For the most part, the etiology of anemia is preventable and includes inadequate diet, poor living conditions, and high infection rates (i.e., malaria and intestinal parasites). A concerted global effort is needed to reduce the worldwide burden of anemia in these marginalized populations.

Difluoromethylornithine is a novel inhibitor of Helicobacter pylori growth, CagA translocation, and interleukin-8 induction

Helicobacter pylori infects half the world's population, and carriage is lifelong without antibiotic therapy. Current regimens prescribed to prevent infection-associated diseases such as gastroduodenal ulcers and gastric cancer can be thwarted by antibiotic resistance. We reported that administration of 1% d,l-α-difluoromethylornithine (DFMO) to mice infected with H. pylori reduces gastritis and colonization, which we attributed to enhanced host immune response due to inhibition of macrophage ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine biosynthesis. Although no ODC has been identified in any H. pylori genome, we sought to determine if DFMO has direct effects on the bacterium. We found that DFMO significantly reduced the growth rate of H. pylori in a polyamine-independent manner. Two other Gram-negative pathogens possessing ODC, Escherichia coli and Citrobacter rodentium, were resistant to the DFMO effect. The effect of DFMO on H. pylori required continuous exposure to the drug and was reversible when removed, with recovery of growth rate in vitro and the ability to colonize mice. H. pylori exposed to DFMO were significantly shorter in length than those untreated and they contained greater internal levels of ATP, suggesting severe effects on bacterial metabolism. DFMO inhibited expression of the H. pylori virulence factor cytotoxin associated gene A, and its translocation and phosphorylation in gastric epithelial cells, which was associated with a reduction in interleukin-8 expression. These findings suggest that DFMO has effects on H. pylori that may contribute to its effectiveness in reducing gastritis and colonization and may be a useful addition to anti-H. pylori therapies.

The characterization of Helicobacter pylori DNA associated with ancient human remains recovered from a Canadian glacier

Helicobacter pylori is a gram-negative bacterium that colonizes the stomach of nearly half of the world's population. Genotypic characterization of H. pylori strains involves the analysis of virulence-associated genes, such as vacA, which has multiple alleles. Previous phylogenetic analyses have revealed a connection between modern H. pylori strains and the movement of ancient human populations. In this study, H. pylori DNA was amplified from the stomach tissue of the Kwäday Dän Ts'ìnchi individual. This ancient individual was recovered from the Samuel Glacier in Tatshenshini-Alsek Park, British Columbia, Canada on the traditional territory of the Champagne and Aishihik First Nations and radiocarbon dated to a timeframe of approximately AD 1670 to 1850. This is the first ancient H. pylori strain to be characterized with vacA sequence data. The Tatshenshini H. pylori strain has a potential hybrid vacA m2a/m1d middle (m) region allele and a vacA s2 signal (s) region allele. A vacA s2 allele is more commonly identified with Western strains, and this suggests that European strains were present in northwestern Canada during the ancient individual's time. Phylogenetic analysis indicated that the vacA m1d region of the ancient strain clusters with previously published novel Native American strains that are closely related to Asian strains. This indicates a past connection between the Kwäday Dän Ts'ìnchi individual and the ancestors who arrived in the New World thousands of years ago.

The epidemiology of Helicobacter pylori and public health implications

This article presents a review of the literature on the epidemiology and public health implications of Helicobacter pylori infection published from April 2008 through to March 2009. The authors used MeSH terms "Helicobacter infections epidemiology,""Helicobacter infections prevention and control" to search multiple databases (PubMed, Embase, Cochrane, Cochrane Library, EBMR, BIOSIS), and independently searched PubMed using the term "Helicobacter" with "Epidemiology,""Transmission,""Prevalence" or "Environment." Articles without topical relevance were excluded. Two additional papers known to the authors were added. The identified literature is summarized by subtopic: reviews; prevalence; incidence; transmission; risk factors; and public health policy.

Helicobacter pylori infection in Canada's arctic: searching for the solutions

The Canadian North Helicobacter pylori (CANHelp) working group is a team composed of investigators, health officials and community leaders from Alberta and the Northwest Territories. The group's initial goals are to investigate the impact of H pylori infection on Canada's Arctic communities; subsequent goals include identifying treatment strategies that are effective in this region and developing recommendations for health policy aimed at management of H pylori infection. The team's investigations have begun with the Aklavik H pylori Project in the Aboriginal community of Aklavik, Northwest Territories.