Recent Cholera Publications on PubMed

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Efficacy of a bivalent killed whole-cell cholera vaccine over five years: a re-analysis of a cluster-randomized trial.

February 22, 2018
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Efficacy of a bivalent killed whole-cell cholera vaccine over five years: a re-analysis of a cluster-randomized trial.

BMC Infect Dis. 2018 Feb 20;18(1):84

Authors: Fong Y, Halloran ME, Park JK, Marks F, Clemens JD, Chao DL

Abstract
BACKGROUND: Oral cholera vaccine (OCV) is a feasible tool to prevent or mitigate cholera outbreaks. A better understanding of the vaccine's efficacy among different age groups and how rapidly its protection wanes could help guide vaccination policy.
METHODS: To estimate the level and duration of OCV efficacy, we re-analyzed data from a previously published cluster-randomized, double-blind, placebo controlled trial with five years of follow-up. We used a Cox proportional hazards model and modeled the potentially time-dependent effect of age categories on both vaccine efficacy and risk of infection in the placebo group. In addition, we investigated the impact of an outbreak period on model estimation.
RESULTS: Vaccine efficacy was 38% (95% CI: -2%,62%) for those vaccinated from ages 1 to under 5 years old, 85% (95% CI: 67%,93%) for those 5 to under 15 years, and 69% (95% CI: 49%,81%) for those vaccinated at ages 15 years and older. Among adult vaccinees, efficacy did not appear to wane during the trial, but there was insufficient data to assess the waning of efficacy among child vaccinees.
CONCLUSIONS: Through this re-analysis we were able to detect a statistically significant difference in OCV efficacy when the vaccine was administered to children under 5 years old vs. children 5 years and older. The estimated efficacies are more similar to the previously published analysis based on the first two years of follow-up than the analysis based on all five years.
TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT00289224.

PMID: 29463233 [PubMed - in process]

Species A rotaviruses isolated from hospitalized patients over 5 years of age in Kolkata, India, in 2012/13.

February 21, 2018
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Species A rotaviruses isolated from hospitalized patients over 5 years of age in Kolkata, India, in 2012/13.

Arch Virol. 2018 Mar;163(3):745-750

Authors: Nayak MK, De P, Manna B, Dutta S, Bhadra UK, Chawla-Sarkar M

Abstract
In hospital-based diarrhoeal disease surveillance at Infectious Diseases & Beliaghata-General Hospital (May-2012 to April-2013), Kolkata, India, stool samples were collected from patients < 5 years (n = 830) and > 5 years of age (n = 728) hospitalized with diarrhea. Group-A rotavirus (GARV) was identified by ELISA followed by multiplex RT-PCR. In children < 5 years of age, 53.4% of the samples were positive for GARV. In patients > 5 years to 90 years old, only 6.04% (n = 44) tested positive for GARV. G2P[4] strains (n = 16 [36.36%]) were the most prevalent, followed by G9P[4] strains (n = 13 [29.54%]), while P[4]-(n = 30 [68.18%]) was most prevalent among the P genotypes. The GARV strains G2, G9 and P[4] detected in adults clustered together in the phylogenetic tree with the GARV strains identified in children (< 5 years) during the same period. Rotavirus positivity was high among female patients (75%), suggesting that caregivers (mother/grandmother/older-siblings) may get infected through young children or may act as carriers for transmission.

PMID: 29248967 [PubMed - indexed for MEDLINE]

Natural Disasters and Cholera Outbreaks: Current Understanding and Future Outlook.

February 21, 2018
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Natural Disasters and Cholera Outbreaks: Current Understanding and Future Outlook.

Curr Environ Health Rep. 2017 Mar;4(1):99-107

Authors: Jutla A, Khan R, Colwell R

Abstract
PURPOSE OF REVIEW: Diarrheal diseases remain a serious global public health threat, especially for those populations lacking access to safe water and sanitation infrastructure. Although association of several diarrheal diseases, e.g., cholera, shigellosis, etc., with climatic processes has been documented, the global human population remains at heightened risk of outbreak of diseases after natural disasters, such as earthquakes, floods, or droughts. In this review, cholera was selected as a signature diarrheal disease and the role of natural disasters in triggering and transmitting cholera was analyzed.
RECENT FINDINGS: Key observations include identification of an inherent feedback loop that includes societal structure, prevailing climatic processes, and spatio-temporal seasonal variability of natural disasters. Data obtained from satellite-based remote sensing are concluded to have application, although limited, in predicting risks of a cholera outbreak(s). We argue that with the advent of new high spectral and spatial resolution data, earth observation systems should be seamlessly integrated in a decision support mechanism to be mobilize resources when a region suffers a natural disaster. A framework is proposed that can be used to assess the impact of natural disasters with response to outbreak of cholera, providing assessment of short- and long-term influence of climatic processes on disease outbreaks.

PMID: 28130661 [PubMed - indexed for MEDLINE]

Characterization of Interventional Studies of the Cholera Epidemic in Haiti.

February 20, 2018
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Characterization of Interventional Studies of the Cholera Epidemic in Haiti.

Prehosp Disaster Med. 2018 Feb 19;:1-6

Authors: Miller J, Birnbaum ML

Abstract
In October 2010, the Haitian Ministry of Public Health and Population (MSPP; Port au Prince, Haiti) reported a cholera epidemic caused by contamination of the Artibonite River by a United Nation Stabilization Mission camp. Interventional studies of the subsequent responses, including a descriptive Methods section and systematic approach, may be useful in facilitating comparisons and applying lessons learned to future outbreaks. The purpose of this study was to examine publicly available documents relating to the 2010 cholera outbreak to answer: (1) What information is publicly available on interventional studies conducted during the epidemic, and what was/were the impact(s)? and (2) Can the interventions be compared, and what lessons can be learned from their comparison? A PubMed (National Center for Biotechnology Information, National Institutes of Health; Bethesda, Maryland USA) search was conducted using the parameters "Haiti" and "cholera." Studies were categorized as "interventional research," "epidemiological research," or "other." A distinction was made between studies and narrative reports. The PubMed search yielded 171 papers, 59 (34.0%) of which were epidemiological and 12 (7.0%) were interventional studies. The remaining 100 papers (59.0%) comprised largely of narrative, anecdotal descriptions. An expanded examination of publications by the World Health Organization (WHO; Geneva, Switzerland), the Center for Research in the Epidemiology of Disasters (CRED; Brussels, Belgium), United States Agency for International Development (USAID; Washington, DC USA)-Development Experience Clearinghouse (DEC), and US National Library of Medicine's (NLM; Bethesda, Maryland USA) Disaster Literature databases yielded no additional interventional studies. The unstructured formats and differing levels of detail prohibited comparisons between interventions, even between those with a similar approach. Only two (17.0%) interventional studies included any impact data, although neither commented whether the intervention improved health or reduced incidence or mortality related to cholera. Agreed frameworks for guiding responses and subsequent reporting are needed to ensure reports contain sufficient detail to draw conclusions for the definition of best practices and for the design of future interventions. Miller J , Birnbaum ML . Characterization of interventional studies of the cholera epidemic in Haiti.

PMID: 29455682 [PubMed - as supplied by publisher]

A case control study investigating factors associated with high infant death in Saiha district of Mizoram, India bordering Myanmar.

February 20, 2018
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A case control study investigating factors associated with high infant death in Saiha district of Mizoram, India bordering Myanmar.

BMC Pediatr. 2017 Jan 17;17(1):23

Authors: Deb AK, Dutta S, Hnichho C, Vanlalpeki M, Phosa HT, Rakhu K, Fanai SL, Chakrabarti M, Panda S

Abstract
BACKGROUND: Infant mortality has dropped considerably in India over the last 5 years. A sharp contrast to this decline in national average of infant mortality is the rate recorded during 2014-2015 from the southernmost district of Saiha, Mizoram having a common international border with Myanmar. As this district specific rate (113 per 1000 live births) is 3 times higher compared to the national and state average, the present investigation was carried out to identify associated factors.
METHODS: We examined secondary data made available by the national health mission, consulted with local community members and generated primary data through interviews. A case-control study design was followed. Mothers, who delivered a child during 2013-2015 and subsequently lost them due to infant death, formed the case group and controls were selected from same neighborhood as with case-mothers. The mother and child tracking system maintained by the district specific national health mission office was used for recruiting cases and controls. A total of 195 mothers were interviewed; 66 of them belonged to 'cases' and 129 were 'controls'.
RESULTS: The mean age of the respondents was 27 years (median 27; SD ± 5; minimum 17 & maximum 44). In uni-variate analyses 'child delivery at home', 'low birth weight', 'non-attendance of school by mothers', 'completed standard of school education by mothers', 'both parents working', 'mothers receiving blood transfusion during last pregnancy', and 'fourth or more birth order during last pregnancy' were associated with infant deaths. Intriguingly, the number of daily kuhva (raw areca nut) intake during last pregnancy was significantly higher among case-mothers compared to controls. In conditional logistic regression, 'low birth weight' (adjusted OR (AOR) 14.7; 95% CI 2.1-101.8; p = 0.006), and 'consumption of 4 or more kuhva per day' (AOR 8; 95% CI 1.9-34.3; p = 0.005) were independently associated with infant-death-experiences.
CONCLUSION: The present investigation merits due attention from policy makers and health planners for immediate improvement in peri-natal and neonatal care services in the remote district of Saiha. Need for further research exploring socio-behavioural issues around areca nut consumption and effects of interventions to reduce areca nut intake on maternal and children health are underscored.

PMID: 28095802 [PubMed - indexed for MEDLINE]

Cholera cases cluster in time and space in Matlab, Bangladesh: implications for targeted preventive interventions.

February 13, 2018
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Cholera cases cluster in time and space in Matlab, Bangladesh: implications for targeted preventive interventions.

Int J Epidemiol. 2016 Dec 01;45(6):2134-2139

Authors: Debes AK, Ali M, Azman AS, Yunus M, Sack DA

Abstract
Background: : Cholera remains a serious public health threat in Asia, Africa and in parts of the Americas. Three World health Organization (WHO) pre-qualified oral cholera vaccines are now available but their supply is limited, so current supplies must be administered strategically. This requires an improved understanding of disease transmission and control strategies.
Methods: : We used demographics and disease surveillance data collected from 1991 to 2000 in Matlab, Bangladesh, to estimate the spatial and temporal extent of the zone of increased risk around cholera cases. Specifically, we compare the cholera incidence among individuals living close to cholera cases with that among individuals living close to those without medically-attended cholera in this rural endemic setting.
Results: : Those living within 50 m of a confirmed cholera case had 36 times (95% confidence interval: 23-56) the risk of becoming a cholera case in the first 3 days (after case presentation) compared with risk elsewhere in the community. The relative risk gradually declined in space and time, but remained significantly high up to 450 me away within 3 days of case presentation, and up to 150 m away within 23 days from the date of presentation of the case.
Conclusion: : These findings suggest that, if conducted rapidly, vaccinating individuals living close to a case (ring vaccination) could be an efficient and effective strategy to target vaccine to a high-risk population in an endemic setting.

PMID: 27789673 [PubMed - indexed for MEDLINE]

Cholera outbreak caused by drinking lake water contaminated with human faeces in Kaiso Village, Hoima District, Western Uganda, October 2015.

February 10, 2018
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Cholera outbreak caused by drinking lake water contaminated with human faeces in Kaiso Village, Hoima District, Western Uganda, October 2015.

Infect Dis Poverty. 2017 Oct 10;6(1):146

Authors: Oguttu DW, Okullo A, Bwire G, Nsubuga P, Ario AR

Abstract
BACKGROUND: On 12 October 2015, a cholera outbreak involving 65 cases and two deaths was reported in a fishing village in Hoima District, Western Uganda. Despite initial response by the local health department, the outbreak persisted. We conducted an investigation to identify the source and mode of transmission, and recommend evidence-led interventions to control and prevent cholera outbreaks in this area.
METHODS: We defined a suspected case as the onset of acute watery diarrhoea from 1 October to 2 November 2015 in a resident of Kaiso Village. A confirmed case was a suspected case who had Vibrio cholerae isolated from stool. We found cases by record review and active community case finding. We performed descriptive epidemiologic analysis for hypothesis generation. In an unmatched case-control study, we compared exposure histories of 61 cases and 126 controls randomly selected among asymptomatic village residents. We also conducted an environmental assessment and obtained meteorological data from a weather station.
RESULTS: We identified 122 suspected cases, of which six were culture-confirmed, 47 were confirmed positive with a rapid diagnostic test and two died. The two deceased cases had onset of the disease on 2 October and 10 October, respectively. Heavy rainfall occurred on 7-11 October; a point-source outbreak occurred on 12-15 October, followed by continuous community transmission for two weeks. Village residents usually collected drinking water from three lakeshore points - A, B and C: 9.8% (6/61) of case-persons and 31% (39/126) of control-persons were found to usually use point A, 21% (13/61) of case-persons and 37% (46/126) of control-persons were found to usually use point B (OR = 1.8, 95% CI: 0.64-5.3), and 69% (42/61) of case-persons and 33% (41/126) of control-persons were found to usually use point C (OR = 6.7; 95% CI: 2.5-17) for water collection. All case-persons (61/61) and 93% (117/126) of control-persons reportedly never treated/boiled drinking water (OR = ∞, 95% CI Fisher: 1.0 - ∞). The village's piped water system had been vandalised and open defecation was common due to a lack of latrines. The lake water was found to be contiminated due to a gully channel that washed the faeces into the lake at point C.
CONCLUSIONS: This outbreak was likely caused by drinking lake water contaminated by faeces from a gully channel. We recommend treatment of drinking water, fixing the vandalised piped-water system and constructing latrines.

PMID: 28992811 [PubMed - indexed for MEDLINE]

Oral Cholera Vaccine Coverage during an Outbreak and Humanitarian Crisis, Iraq, 2015.

February 10, 2018
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Oral Cholera Vaccine Coverage during an Outbreak and Humanitarian Crisis, Iraq, 2015.

Emerg Infect Dis. 2017 01;23(1):38-45

Authors: Lam E, Al-Tamimi W, Russell SP, Butt MO, Blanton C, Musani AS, Date K

Abstract
During November-December 2015, as part of the 2015 cholera outbreak response in Iraq, the Iraqi Ministry of Health targeted ≈255,000 displaced persons >1 year of age with 2 doses of oral cholera vaccine (OCV). All persons who received vaccines were living in selected refugee camps, internally displaced persons camps, and collective centers. We conducted a multistage cluster survey to obtain OCV coverage estimates in 10 governorates that were targeted during the campaign. In total, 1,226 household and 5,007 individual interviews were conducted. Overall, 2-dose OCV coverage in the targeted camps was 87% (95% CI 85%-89%). Two-dose OCV coverage in the 3 northern governorates (91%; 95% CI 87%-94%) was higher than that in the 7 southern and central governorates (80%; 95% CI 77%-82%). The experience in Iraq demonstrates that OCV campaigns can be successfully implemented as part of a comprehensive response to cholera outbreaks among high-risk populations in conflict settings.

PMID: 27983502 [PubMed - indexed for MEDLINE]

The impact of internal displacement on child mortality in post-earthquake Haiti: a difference-in-differences analysis.

February 10, 2018
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The impact of internal displacement on child mortality in post-earthquake Haiti: a difference-in-differences analysis.

Int J Equity Health. 2016 Jul 19;15(1):114

Authors: Chen B, Halliday TJ, Fan VY

Abstract
BACKGROUND: The Haiti earthquake in 2010 resulted in 1.5 million internally displaced people (IDP), yet little is known about the impact of displacement on health. In this study, we estimate the impact of displacement on infant and child mortality and key health-behavior mechanisms.
METHODS: We employ a difference-in-differences (DID) design with coarsened exact matching (CEM) to ensure comparability among groups with different displacement status using the 2012 Haiti Demographic and Health Survey (DHS). The participants are 21,417 births reported by a nationally representative sample of 14,287 women aged 15-49. The main independent variables are household displacement status which includes households living in camps, IDP households (not in camps), and households not displaced. The main outcomes are infant and child mortality; health status (height-for-age, anemia); uptake of public health interventions (bed net use, spraying against mosquitoes, and vaccinations); and other conditions (hunger; cholera).
RESULTS: Births from the camp households have higher infant mortality (OR = 2.34, 95 % CI 1.15 to 4.75) and child mortality (OR = 2.34, 95 % CI 1.10 to 5.00) than those in non-camp IDP households following the earthquake. These odds are higher despite better access to food, water, bed net use, mosquito spraying, and vaccines among camp households.
CONCLUSIONS: IDP populations are heterogeneous and households that are displaced outside of camps may be self-selected or self-insured. Meanwhile, even households not displaced by a disaster may face challenges in access to basic necessities and health services. Efforts are needed to identify vulnerable populations to provide targeted assistance in post-disaster relief.

PMID: 27435004 [PubMed - indexed for MEDLINE]

Patterns and predictors of undiagnosed and uncontrolled hypertension: observations from a poor-resource setting.

February 10, 2018
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Patterns and predictors of undiagnosed and uncontrolled hypertension: observations from a poor-resource setting.

J Hum Hypertens. 2017 Jan;31(1):56-65

Authors: Kanungo S, Mahapatra T, Bhowmik K, Saha J, Mahapatra S, Pal D, Roy R, Bhadra UK, Sarkar K

Abstract
Early detection is the cornerstone of hypertension management; still majority remains undetected until complications arise, especially in poor-resource settings. Paucity of information regarding undiagnosed and uncontrolled hypertension in eastern India thus called for a detailed investigation involving a representative sample of adults in Malda, one of the poorest districts in the region. In a cross-sectional study, between October 2013 and July 2014, using multistage random sampling with probability-proportional-to-size, 18 028 consenting adults were interviewed. Diagnosed cases were defined as uncontrolled if they still had hypertensive level of blood pressure (according to JNC-VIII criteria) while those detected during this study were defined as undiagnosed. Descriptive and regression analyses were performed using SAS version 9.3.2. Among 18 028 participants, 4695 (26.04% (95% confidence intervals: 95% CI=25.40-26.68)) had hypertension, of which 3937 (83.86% (82.80-84.91)) were undiagnosed and 548 (72.30 (69.10-75.49)) had uncontrolled hypertension. Relatively older subjects (adjusted Odds ratio (aOR)41-60 years=0.34 (95% CI=0.26-0.43) and aOR>60 years=0.29 (0.21-0.38)), who were divorced/separated/widowed/widower (aOR=0.76 (0.61-0.95)), had higher education (aOR=0.61 (0.43-0.88)), better socio-economic status (SES) (aORMiddle=0.77 (0.60-0.99) and aORUpper=0.64 (0.48-0.85)) and urban residence (aOR=0.44 (0.36-0.55)) were less likely while subjects who belonged to backward castes (aOR=1.37 (1.15-1.64)) were more likely to have undiagnosed hypertension. Odds of having uncontrolled hypertension were higher among participants aged >60 years (aOR=2.25 (1.27-3.99)). Burden of hypertension (diagnosed and undiagnosed) was high in Malda district of West Bengal. Significant predictors of undiagnosed hypertension were young age, backward caste, poor education and lower SES, while older subjects had poor control. Thus, appropriate surveillance targeting these at-risk groups might be effective in controlling hypertension in similar poor-resource settings.

PMID: 27193382 [PubMed - indexed for MEDLINE]

Single-Dose Cholera Vaccine in Response to an Outbreak in Zambia.

February 8, 2018

Single-Dose Cholera Vaccine in Response to an Outbreak in Zambia.

N Engl J Med. 2018 Feb 08;378(6):577-579

Authors: Ferreras E, Chizema-Kawesha E, Blake A, Chewe O, Mwaba J, Zulu G, Poncin M, Rakesh A, Page AL, Stoitsova S, Voute C, Uzzeni F, Robert H, Serafini M, Matapo B, Eiros JM, Quilici ML, Pezzoli L, Azman AS, Cohuet S, Ciglenecki I, Malama K, Luquero FJ

PMID: 29414267 [PubMed - in process]

A PELAGIC OUTBREAK OF AVIAN CHOLERA IN NORTH AMERICAN GULLS: SCAVENGING AS A PRIMARY MECHANISM FOR TRANSMISSION?

February 6, 2018
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A PELAGIC OUTBREAK OF AVIAN CHOLERA IN NORTH AMERICAN GULLS: SCAVENGING AS A PRIMARY MECHANISM FOR TRANSMISSION?

J Wildl Dis. 2016 Oct;52(4):793-802

Authors: Wille M, McBurney S, Robertson GJ, Wilhelm SI, Blehert DS, Soos C, Dunphy R, Whitney H

Abstract
Avian cholera, caused by the bacterium Pasteurella multocida , is an endemic disease globally, often causing annual epizootics in North American wild bird populations with thousands of mortalities. From December 2006 to March 2007, an avian cholera outbreak caused mortality in marine birds off the coast of Atlantic Canada, largely centered 300-400 km off the coast of the island of Newfoundland. Scavenging gulls ( Larus spp.) were the primary species detected; however, mortality was also identified in Black-legged Kittiwakes ( Rissa tridactyla ) and one Common Raven ( Corvus corax ), a nonmarine species. The most common gross necropsy findings in the birds with confirmed avian cholera were acute fibrinous and necrotizing lesions affecting the spleen, air sacs, and pericardium, and nonspecific hepatomegaly and splenomegaly. The etiologic agent, P. multocida serotype 1, was recovered from 77 of 136 carcasses examined, and confirmed or probable avian cholera was diagnosed in 85 cases. Mortality observed in scavenging gull species was disproportionately high relative to their abundance, particularly when compared to nonscavenging species. The presence of feather shafts in the ventricular lumen of the majority of larid carcasses diagnosed with avian cholera suggests scavenging of birds that died from avian cholera as a major mode of transmission. This documentation of an outbreak of avian cholera in a North American pelagic environment affecting primarily scavenging gulls indicates that offshore marine environments may be a component of avian cholera dynamics.

PMID: 27455197 [PubMed - indexed for MEDLINE]

Travel-Associated Vibrio cholerae O1 El Tor, Russia.

February 2, 2018
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Travel-Associated Vibrio cholerae O1 El Tor, Russia.

Emerg Infect Dis. 2016 11;22(11):2006-2008

Authors: Kuleshov KV, Vodop'ianov SO, Dedkov VG, Markelov ML, Deviatkin AA, Kruglikov VD, Vodop'ianov AS, Pisanov RV, Mazrukho AB, Titova SV, Maleev VV, Shipulin GA

PMID: 27767910 [PubMed - indexed for MEDLINE]

Vibrio cholerae O1 Imported from Iraq to Kuwait, 2015.

February 2, 2018
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Vibrio cholerae O1 Imported from Iraq to Kuwait, 2015.

Emerg Infect Dis. 2016 09;22(9):1693-4

Authors: Mukhopadhyay AK, Al Benwan K, Samanta P, Chowdhury G, Albert MJ

PMID: 27532267 [PubMed - indexed for MEDLINE]

Identifying cholera "hotspots" in Uganda: An analysis of cholera surveillance data from 2011 to 2016.

January 31, 2018
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Identifying cholera "hotspots" in Uganda: An analysis of cholera surveillance data from 2011 to 2016.

PLoS Negl Trop Dis. 2017 12;11(12):e0006118

Authors: Bwire G, Ali M, Sack DA, Nakinsige A, Naigaga M, Debes AK, Ngwa MC, Brooks WA, Garimoi Orach C

Abstract
BACKGROUND: Despite advance in science and technology for prevention, detection and treatment of cholera, this infectious disease remains a major public health problem in many countries in sub-Saharan Africa, Uganda inclusive. The aim of this study was to identify cholera hotspots in Uganda to guide the development of a roadmap for prevention, control and elimination of cholera in the country.
METHODOLOGY/PRINCIPLE FINDINGS: We obtained district level confirmed cholera outbreak data from 2011 to 2016 from the Ministry of Health, Uganda. Population and rainfall data were obtained from the Uganda Bureau of Statistics, and water, sanitation and hygiene data from the Ministry of Water and Environment. A spatial scan test was performed to identify the significantly high risk clusters. Cholera hotspots were defined as districts whose center fell within a significantly high risk cluster or where a significantly high risk cluster was completely superimposed onto a district. A zero-inflated negative binomial regression model was employed to identify the district level risk factors for cholera. In total 11,030 cases of cholera were reported during the 6-year period. 37(33%) of 112 districts reported cholera outbreaks in one of the six years, and 20 (18%) districts experienced cholera at least twice in those years. We identified 22 districts as high risk for cholera, of which 13 were near a border of Democratic Republic of Congo (DRC), while 9 districts were near a border of Kenya. The relative risk of having cholera inside the high-risk districts (hotspots) were 2 to 22 times higher than elsewhere in the country. In total, 7 million people were within cholera hotspots. The negative binomial component of the ZINB model shows people living near a lake or the Nile river were at increased risk for cholera (incidence rate ratio, IRR = 0.98, 95% CI: 0.97 to 0.99, p < .01); people living near the border of DRC/Kenya or higher incidence rate in the neighboring districts were increased risk for cholera in a district (IRR = 0.99, 95% CI: 0.98 to 1.00, p = .02 and IRR = 1.02, 95% CI: 1.01 to 1.03, p < .01, respectively). The zero inflated component of the ZINB model yielded shorter distance to Kenya or DRC border, higher incidence rate in the neighboring districts, and higher annual rainfall in the district were associated with the risk of having cholera in the district.
CONCLUSIONS/SIGNIFICANCE: The study identified cholera hotspots during the period 2011-2016. The people located near the international borders, internationally shared lakes and river Nile were at higher risk for cholera outbreaks than elsewhere in the country. Targeting cholera interventions to these locations could prevent and ultimately eliminate cholera in Uganda.

PMID: 29284003 [PubMed - indexed for MEDLINE]

Cholera - management and prevention.

January 31, 2018
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Cholera - management and prevention.

J Infect. 2017 Jun;74 Suppl 1:S66-S73

Authors: Davies HG, Bowman C, Luby SP

Abstract
Cholera is an acute secretory diarrhoeal infection caused by the bacterium Vibrio cholerae. It is likely to have originated in the Indian sub-continent; however, it spread to cause six worldwide pandemics between 1817-1923. The ongoing seventh worldwide pandemic of cholera began in 1961. The intensity, duration and severity of cholera epidemics have been increasing, signaling the need for more effective control and prevention measures. The response to the cholera pandemics of the 19th century led to the development of safe and effective sanitation and water systems which have effectively removed the risk of cholera in many settings. However, such systems are not in place to protect billions of people worldwide. Although some progress has been made in expanding access to water in recent years, achieving optimal infrastructure will, in the most optimistic scenario, take decades. Climate change, extreme weather events and rapid urbanisation suggests that alternatives to the current paradigm of providing large centralised water and sanitation systems should be considered, including smaller decentralised systems. The aim of this review paper is to provide an overview of current knowledge regarding management of cholera with a focus on prevention measures including vaccination and water and sanitation interventions.

PMID: 28646965 [PubMed - indexed for MEDLINE]

Dried Blood Spots for Measuring Vibrio cholerae-specific Immune Responses.

January 30, 2018

Dried Blood Spots for Measuring Vibrio cholerae-specific Immune Responses.

PLoS Negl Trop Dis. 2018 Jan 29;12(1):e0006196

Authors: Iyer AS, Azman AS, Bouhenia M, Deng LO, Anderson CP, Graves M, Kováč P, Xu P, Ryan ET, Harris JB, Sack DA, Luquero FJ, Leung DT

Abstract
BACKGROUND: Vibrio cholerae causes over 2 million cases of cholera and 90,000 deaths each year. Serosurveillance can be a useful tool for estimating the intensity of cholera transmission and prioritizing populations for cholera control interventions. Current methods involving venous blood draws and downstream specimen storage and transport methods pose logistical challenges in most settings where cholera strikes. To overcome these challenges, we developed methods for determining cholera-specific immune responses from dried blood spots (DBS).
METHODOLOGY/PRINCIPAL FINDINGS: As conventional vibriocidal assay methods were unsuitable for DBS eluates from filter paper, we adopted a drop-plate culture method. We show that DBS collected from volunteers in South Sudan, and stored for prolonged periods in field conditions, retained functional vibriocidal antibodies, the titers of which correlated with paired serum titers determined by conventional spectrophotometric methods (r = 0.94, p = 0.00012). We also showed that eluates from DBS Serum Separator cards could be used with conventional spectrophotometric vibriocidal methods, and that they correlated with paired serum at a wide range of titers (r = 0.96, p<0.0001). Similarly, we used ELISA methods to show that V. cholerae O-specific polysaccharide antibody responses from DBS eluates correlated with results from paired serum for IgG (r = 0.85, p = 0.00006), IgM (r = 0.79, p = 0.00049) and IgA (r = 0.73, p = 0.0019), highlighting its potential for use in determination of isotype-specific responses. Storage of DBS cards at a range of temperatures did not change antibody responses.
CONCLUSION: In conclusion, we have developed and demonstrated a proof-of-concept for assays utilizing DBS for assessing cholera-specific immune responses.

PMID: 29377882 [PubMed - as supplied by publisher]

Genetic diversity of environmental Vibrio cholerae O1 strains isolated in Northern Vietnam.

January 30, 2018
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Genetic diversity of environmental Vibrio cholerae O1 strains isolated in Northern Vietnam.

Infect Genet Evol. 2017 Oct;54:146-151

Authors: Takemura T, Murase K, Maruyama F, Tran TL, Ota A, Nakagawa I, Nguyen DT, Ngo TC, Nguyen TH, Tokizawa A, Morita M, Ohnishi M, Nguyen BM, Yamashiro T

Abstract
Cholera epidemics have been recorded periodically in Vietnam during the seventh cholera pandemic. Since cholera is a water-borne disease, systematic monitoring of environmental waters for Vibrio cholerae presence is important for predicting and preventing cholera epidemics. We conducted monitoring, isolation, and genetic characterization of V. cholerae strains in Nam Dinh province of Northern Vietnam from Jul 2013 to Feb 2015. In this study, four V. cholerae O1 strains were detected and isolated from 110 analyzed water samples (3.6%); however, none of them carried the cholera toxin gene, ctxA, in their genomes. Whole genome sequencing and phylogenetic analysis revealed that the four O1 isolates were separated into two independent clusters, and one of them diverged from a common ancestor with pandemic strains. The analysis of pathogenicity islands (CTX prophage, VPI-I, VPI-II, VSP-I, and VSP-II) indicated that one strain (VNND_2014Jun_6SS) harbored an unknown prophage-like sequence with high homology to vibriophage KSF-1 phi and VCY phi, identified from Bangladesh and the USA, respectively, while the other three strains carried tcpA gene with a distinct sequence demonstrating a separate clonal lineage. These results suggest that the aquatic environment can harbor highly divergent V. cholera strains and serve as a reservoir for multiple V. cholerae virulence-associated genes which may be exchanged via mobile genetic elements. Therefore, continuous monitoring and genetic characterization of V. cholerae strains in the environment should contribute to the early detection of the sources of infection and prevention of cholera outbreaks as well as to understanding the natural ecology and evolution of V. cholerae.

PMID: 28642158 [PubMed - indexed for MEDLINE]

Characterization of Vibrio cholerae O1 strains that trace the origin of Haitian-like genetic traits.

January 30, 2018
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Characterization of Vibrio cholerae O1 strains that trace the origin of Haitian-like genetic traits.

Infect Genet Evol. 2017 Oct;54:47-53

Authors: Ghosh P, Kumar D, Chowdhury G, Singh P, Samanta P, Dutta S, Ramamurthy T, Sharma NC, Sinha P, Prasad Y, Shinoda S, Mukhopadhyay AK

Abstract
Vibrio cholerae O1 is the etiological agent of the severe diarrheal disease cholera. The bacterium has recently been causing outbreaks in Haiti with catastrophic effects. Numerous mutations have been reported in V. cholerae O1 strains associated with the Haitian outbreak. These mutations encompass among other the genes encoding virulence factors such as the pilin subunit of the toxin-co-regulated pilus (tcpA), cholera toxin B subunit (ctxB), repeat in toxins (rtxA), and other genes such as the quinolone resistance-determining region (QRDR) of gyrase A (gyrA), rstB of RS element along with the alteration in the number of repeat sequences at the promoter region of ctxAB. Given the numerous genetic changes in those Haitian isolates, we decided to investigate the possible origins of those variations in the Indian subcontinent. Thus, we determined the genetic traits among V. cholerae O1 strains in Delhi, India. A total of 175 strains isolated from cholera patients during 2004 to 2012 were analysed in the present study. Our results showed that all the tested strains carried Haitian type tcpA (tcpACIRS) and variant gyrA indicating their first appearance before 2004 in Delhi. The Haitian variant rtxA and ctxB7 were first detected in Delhi during 2004 and 2006, respectively. Interestingly, not a single strain with the combination of El Tor rtxA and ctxB7 was detected in this study. The Delhi strains carried four heptad repeats (TTTTGAT) in the CT promoter region whereas Haitian strains carried 5 such repeats. Delhi strains did not have any deletion mutations in the rstB like Haitian strains. Overall, our study demonstrates the sequential accumulation of Haitian-like genetic traits among V. cholerae O1 strains in Delhi at different time points prior to the Haitian cholera outbreak.

PMID: 28625543 [PubMed - indexed for MEDLINE]

Evolution of atypical enteropathogenic E. coli by repeated acquisition of LEE pathogenicity island variants.

January 30, 2018
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Evolution of atypical enteropathogenic E. coli by repeated acquisition of LEE pathogenicity island variants.

Nat Microbiol. 2016 Jan 18;1:15010

Authors: Ingle DJ, Tauschek M, Edwards DJ, Hocking DM, Pickard DJ, Azzopardi KI, Amarasena T, Bennett-Wood V, Pearson JS, Tamboura B, Antonio M, Ochieng JB, Oundo J, Mandomando I, Qureshi S, Ramamurthy T, Hossain A, Kotloff KL, Nataro JP, Dougan G, Levine MM, Robins-Browne RM, Holt KE

Abstract
Atypical enteropathogenic Escherichia coli (aEPEC) is an umbrella term given to E. coli that possess a type III secretion system encoded in the locus of enterocyte effacement (LEE), but lack the virulence factors (stx, bfpA) that characterize enterohaemorrhagic E. coli and typical EPEC, respectively. The burden of disease caused by aEPEC has recently increased in industrialized and developing nations, yet the population structure and virulence profile of this emerging pathogen are poorly understood. Here, we generated whole-genome sequences of 185 aEPEC isolates collected during the Global Enteric Multicenter Study from seven study sites in Asia and Africa, and compared them with publicly available E. coli genomes. Phylogenomic analysis revealed ten distinct widely distributed aEPEC clones. Analysis of genetic variation in the LEE pathogenicity island identified 30 distinct LEE subtypes divided into three major lineages. Each LEE lineage demonstrated a preferred chromosomal insertion site and different complements of non-LEE encoded effector genes, indicating distinct patterns of evolution of these lineages. This study provides the first detailed genomic framework for aEPEC in the context of the EPEC pathotype and will facilitate further studies into the epidemiology and pathogenicity of EPEC by enabling the detection and tracking of specific clones and LEE variants.

PMID: 27571974 [PubMed - indexed for MEDLINE]

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