Recent Cholera Publications on PubMed

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Use of oral cholera vaccine as a vaccine probe to define the geographical dimensions of person-to-person transmission of cholera.

3 hours 41 min ago
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Use of oral cholera vaccine as a vaccine probe to define the geographical dimensions of person-to-person transmission of cholera.

Int J Infect Dis. 2018 Jan;66:90-95

Authors: Ali M, Kim DR, Kanungo S, Sur D, Manna B, Digilio L, Dutta S, Marks F, Bhattacharya SK, Clemens J

Abstract
BACKGROUND: Cholera is known to be transmitted from person to person, and inactivated oral cholera vaccines (OCVs) have been shown to confer herd protection via interruption of this transmission. However, the geographic dimensions of chains of person-to-person transmission of cholera are uncertain. The ability of OCVs to confer herd protection was used to define these dimensions in two cholera-endemic settings, one in rural Bangladesh and the other in urban India.
METHODS: Two large randomized, placebo-controlled trials of inactivated OCVs, one in rural Matlab, Bangladesh and the other in urban Kolkata, India, were reanalyzed. Vaccine herd protection was evaluated by relating the risk of cholera in placebo recipients to vaccine coverage of surrounding residents residing within concentric rings. In Matlab, concentric rings in 100-m increments up to 700m were evaluated; in Kolkata, 50-m increments up to 350m were evaluated.
RESULTS: One hundred and eight cholera cases among 24667 placebo recipients were detected during 1year of post-vaccination follow-up at Matlab; 128 cholera cases among 34968 placebo recipients were detected during 3 years of follow-up in Kolkata. Consistent inverse relationships were observed between vaccine coverage of the ring and the risk of cholera in the central placebo recipient for rings with radii up to 500m in Matlab and up to 150m in Kolkata.
CONCLUSIONS: These results suggest that the dimensions of chains of person-to-person transmission in endemic settings can be quite large and may differ substantially from setting to setting. Using OCVs as 'probes' to define these dimensions can inform geographical targeting strategies for the deployment of these vaccines in endemic settings.

PMID: 29174695 [PubMed - indexed for MEDLINE]

Immune Responses to an Oral Cholera Vaccine in Internally Displaced Persons in South Sudan.

3 hours 41 min ago
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Immune Responses to an Oral Cholera Vaccine in Internally Displaced Persons in South Sudan.

Sci Rep. 2016 10 24;6:35742

Authors: Iyer AS, Bouhenia M, Rumunu J, Abubakar A, Gruninger RJ, Pita J, Lino RL, Deng LL, Wamala JF, Ryan ET, Martin S, Legros D, Lessler J, Sack DA, Luquero FJ, Leung DT, Azman AS

Abstract
Despite recent large-scale cholera outbreaks, little is known about the immunogenicity of oral cholera vaccines (OCV) in African populations, particularly among those at highest cholera risk. During a 2015 preemptive OCV campaign among internally displaced persons in South Sudan, a year after a large cholera outbreak, we enrolled 37 young children (1-5 years old), 67 older children (6-17 years old) and 101 adults (≥18 years old), who received two doses of OCV (Shanchol) spaced approximately 3 weeks apart. Cholera-specific antibody responses were determined at days 0, 21 and 35 post-immunization. High baseline vibriocidal titers (>80) were observed in 21% of the participants, suggesting recent cholera exposure or vaccination. Among those with titers ≤80, 90% young children, 73% older children and 72% adults seroconverted (≥4 fold titer rise) after the 1st OCV dose; with no additional seroconversion after the 2nd dose. Post-vaccination immunological endpoints did not differ across age groups. Our results indicate Shanchol was immunogenic in this vulnerable population and that a single dose alone may be sufficient to achieve similar short-term immunological responses to the currently licensed two-dose regimen. While we found no evidence of differential response by age, further immunologic and epidemiologic studies are needed.

PMID: 27775046 [PubMed - indexed for MEDLINE]

Risk factors of cholera transmission in rural areas in Haiti.

April 18, 2018
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Risk factors of cholera transmission in rural areas in Haiti.

Med Sante Trop. 2017 Feb 01;27(1):11-15

Authors: Gazin P, Barrais R, Uwineza F

Abstract
Cholera, present in Haiti since October 2010, persisted in early 2014 in several places, each with its own particular epidemiological characteristics. The scarcity of fresh water probably contributed to the spread of the disease in some rural areas. Population gatherings in places without an access to either safe water or sanitation infrastructure were another factor. Outreach activities of hygiene promotion and improving access to chlorinated water had positive results. The disappearance of choléra in areas where effective preventive actions were conducted supports the conclusion that its transmission is predominantly interhuman, without the sustainable installation of the pathogenic Vibrio in the Haitian environment. These actions must be modulated according to the various areas.

PMID: 28406405 [PubMed - indexed for MEDLINE]

Integrated view of Vibrio cholerae in the Americas.

April 11, 2018
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Integrated view of Vibrio cholerae in the Americas.

Science. 2017 11 10;358(6364):789-793

Authors: Domman D, Quilici ML, Dorman MJ, Njamkepo E, Mutreja A, Mather AE, Delgado G, Morales-Espinosa R, Grimont PAD, Lizárraga-Partida ML, Bouchier C, Aanensen DM, Kuri-Morales P, Tarr CL, Dougan G, Parkhill J, Campos J, Cravioto A, Weill FX, Thomson NR

Abstract
Latin America has experienced two of the largest cholera epidemics in modern history; one in 1991 and the other in 2010. However, confusion still surrounds the relationships between globally circulating pandemic Vibrio cholerae clones and local bacterial populations. We used whole-genome sequencing to characterize cholera across the Americas over a 40-year time span. We found that both epidemics were the result of intercontinental introductions of seventh pandemic El Tor V. cholerae and that at least seven lineages local to the Americas are associated with disease that differs epidemiologically from epidemic cholera. Our results consolidate historical accounts of pandemic cholera with data to show the importance of local lineages, presenting an integrated view of cholera that is important to the design of future disease control strategies.

PMID: 29123068 [PubMed - indexed for MEDLINE]

Genomic history of the seventh pandemic of cholera in Africa.

April 11, 2018
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Genomic history of the seventh pandemic of cholera in Africa.

Science. 2017 11 10;358(6364):785-789

Authors: Weill FX, Domman D, Njamkepo E, Tarr C, Rauzier J, Fawal N, Keddy KH, Salje H, Moore S, Mukhopadhyay AK, Bercion R, Luquero FJ, Ngandjio A, Dosso M, Monakhova E, Garin B, Bouchier C, Pazzani C, Mutreja A, Grunow R, Sidikou F, Bonte L, Breurec S, Damian M, Njanpop-Lafourcade BM, Sapriel G, Page AL, Hamze M, Henkens M, Chowdhury G, Mengel M, Koeck JL, Fournier JM, Dougan G, Grimont PAD, Parkhill J, Holt KE, Piarroux R, Ramamurthy T, Quilici ML, Thomson NR

Abstract
The seventh cholera pandemic has heavily affected Africa, although the origin and continental spread of the disease remain undefined. We used genomic data from 1070 Vibrio cholerae O1 isolates, across 45 African countries and over a 49-year period, to show that past epidemics were attributable to a single expanded lineage. This lineage was introduced at least 11 times since 1970, into two main regions, West Africa and East/Southern Africa, causing epidemics that lasted up to 28 years. The last five introductions into Africa, all from Asia, involved multidrug-resistant sublineages that replaced antibiotic-susceptible sublineages after 2000. This phylogenetic framework describes the periodicity of lineage introduction and the stable routes of cholera spread, which should inform the rational design of control measures for cholera in Africa.

PMID: 29123067 [PubMed - indexed for MEDLINE]

Genomes rewrite cholera's global story.

April 11, 2018
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Genomes rewrite cholera's global story.

Science. 2017 Nov 10;358(6364):706-707

Authors: Kupferschmidt K

PMID: 29123042 [PubMed - indexed for MEDLINE]

Dynamics of cholera epidemics from Benin to Mauritania.

April 10, 2018

Dynamics of cholera epidemics from Benin to Mauritania.

PLoS Negl Trop Dis. 2018 Apr 09;12(4):e0006379

Authors: Moore S, Dongdem AZ, Opare D, Cottavoz P, Fookes M, Sadji AY, Dzotsi E, Dogbe M, Jeddi F, Bidjada B, Piarroux M, Valentin OT, Glèlè CK, Rebaudet S, Sow AG, Constantin de Magny G, Koivogui L, Dunoyer J, Bellet F, Garnotel E, Thomson N, Piarroux R

Abstract
BACKGROUND: The countries of West Africa are largely portrayed as cholera endemic, although the dynamics of outbreaks in this region of Africa remain largely unclear.
METHODOLOGY/PRINCIPAL FINDINGS: To understand the dynamics of cholera in a major portion of West Africa, we analyzed cholera epidemics from 2009 to 2015 from Benin to Mauritania. We conducted a series of field visits as well as multilocus variable tandem repeat analysis and whole-genome sequencing analysis of V. cholerae isolates throughout the study region. During this period, Ghana accounted for 52% of the reported cases in the entire study region (coastal countries from Benin to Mauritania). From 2009 to 2015, we found that one major wave of cholera outbreaks spread from Accra in 2011 northwestward to Sierra Leone and Guinea in 2012. Molecular epidemiology analysis confirmed that the 2011 Ghanaian isolates were related to those that seeded the 2012 epidemics in Guinea and Sierra Leone. Interestingly, we found that many countries deemed "cholera endemic" actually suffered very few outbreaks, with multi-year lulls.
CONCLUSIONS/SIGNIFICANCE: This study provides the first cohesive vision of the dynamics of cholera epidemics in a major portion of West Africa. This epidemiological overview shows that from 2009 to 2015, at least 54% of reported cases concerned populations living in the three urban areas of Accra, Freetown, and Conakry. These findings may serve as a guide to better target cholera prevention and control efforts in the identified cholera hotspots in West Africa.

PMID: 29630632 [PubMed - as supplied by publisher]

Evaluation of cholera surveillance system in Osu Klottey District, Accra, Ghana (2011-2013).

April 10, 2018
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Evaluation of cholera surveillance system in Osu Klottey District, Accra, Ghana (2011-2013).

Pan Afr Med J. 2017;28:224

Authors: Adjei EY, Malm KL, Mensah KN, Sackey SO, Ameme D, Kenu E, Abdulai M, Mills R, Afari E

Abstract
Introduction: Cholera is an acute illness characterized by profuse watery diarrhea. It is caused by vibrio cholera subgroup 01 and 0139. Rapid administration of fluid replacement therapy and supportive treatment can reduce mortality to around 1%. By the close of 2011, 10,628 cases and 100 deaths were reported in Ghana with a case fatality rate of 0.99. It is important to evaluate the cholera surveillance system in Ghana to determine if it is meeting its objective.
Methods: The study was conducted in Osu Klottey district in the Accra Metropolitan area in January 2014. We assessed the operations (attributes and performance) of the surveillance system for cholera using CDC guidelines (2001). Surveillance data records at the district level from 2011-2013 were extracted and analyzed for frequency using Microsoft excel. Stakeholders and key informants were interviewed using structured questionnaire. Records were also reviewed at some health facilities and at district levels.
Results: In 2011 and 2012, case fatality rates (1.3% and 0.65%) respectively. Males were mostly affected. The most affected age group was 20-29. In 2011, Predictive value positive was 69.2% and 50% in 2012.Cholera peaked in March 2011 and April 2012. The Government of Ghana funded the system. The system is sensitive, simple, stable, flexible, acceptable and representative. It was also useful and data quality was relatively good. Predictive Value Positive was also good.
Conclusion: The surveillance system is achieving its set out objectives. The system is sensitive, simple, stable, flexible, and acceptable. Predictive value positive was good.

PMID: 29629010 [PubMed - in process]

Yemen and cholera: a modern humanity test.

April 10, 2018
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Yemen and cholera: a modern humanity test.

Lancet. 2017 08 12;390(10095):626

Authors: The Lancet

PMID: 28816124 [PubMed - indexed for MEDLINE]

Antimicrobial Resistance Risks of Cholera Prophylaxis for United Nations Peacekeepers.

April 7, 2018
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Antimicrobial Resistance Risks of Cholera Prophylaxis for United Nations Peacekeepers.

Antimicrob Agents Chemother. 2017 Aug;61(8):

Authors: Kunkel A, Lewnard JA, Pitzer VE, Cohen T

Abstract
More than 5 years after a United Nations peacekeeping battalion introduced cholera to Haiti, over 150,000 peacekeepers continue to be deployed annually from countries where cholera is endemic. The United Nations has thus far declined to provide antimicrobial chemoprophylaxis to peacekeepers, a policy based largely on concerns that the risks of drug resistance generation and spread would outweigh the potential benefits of preventing future cholera importations. In this study, we sought to better understand the relative benefits and risks of cholera chemoprophylaxis for peacekeepers in terms of antibiotic resistance. Using a stochastic model to quantify the potential impact of chemoprophylaxis on importation and transmission of drug-resistant and drug-sensitive Vibrio cholerae, we found that chemoprophylaxis would decrease the probability of cholera importation but would increase the expected number of drug-resistant infections if an importation event were to occur. Despite this potential increase, we found that at least 10 drug-sensitive infections would likely be averted per excess drug-resistant infection under a wide range of assumptions about the underlying prevalence of drug resistance and risk of acquired resistance. Given these findings, policymakers should reconsider whether the potential resistance risks of providing antimicrobial chemoprophylaxis to peacekeepers are sufficient to outweigh the anticipated benefits.

PMID: 28533237 [PubMed - indexed for MEDLINE]

Genetic diversity and virulence potential of clinical and environmental Aeromonas spp. isolates from a diarrhea outbreak.

April 3, 2018
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Genetic diversity and virulence potential of clinical and environmental Aeromonas spp. isolates from a diarrhea outbreak.

BMC Microbiol. 2017 Aug 18;17(1):179

Authors: Silva LCAD, Leal-Balbino TC, Melo BST, Mendes-Marques CL, Rezende AM, Almeida AMP, Leal NC

Abstract
BACKGROUND: Aeromonas spp. are gram-negative bacteria that can cause a variety of infections in both humans and animals and play a controversial role in diarrhea outbreaks. Our aim was to identify clinical and environmental Aeromonas isolates associated with a cholera outbreak in a northeast county of Brazil at the species level. We also aimed to determine the genetic structure of the bacterial population and the virulence potential of the Aeromonas isolates.
METHODS AND RESULTS: Analysis based on concatenated sequences of the 16S rRNA and gyrB genes suggested the classification of the 119 isolates studied into the following species: A. caviae (66.9%), A. veronii (15.3%), A. aquariorum (9.3%), A. trota (3.4%), A. hydrophila (3.4%) and A. jandaei (1.7%). One isolate did not fit any Aeromonas species assessed, which might indicate a new species. The haplotype network based on 16S rRNA gene sequences identified 59 groups among the 119 isolates and 26 reference strains, and it clustered almost all A. caviae isolates into the same group. The analysis of the frequency patterns of seven virulence-associated genes (alt, ast, hlyA, aerA, exu, lip, flaA/B) revealed 29 virulence patterns composed of one to seven genes. All the isolates harbored at least one gene, and three of them harbored all seven virulence genes.
CONCLUSION: The results emphasize the need to improve local water supply and maintain close monitoring of possible bacterial contamination in the drinking water.

PMID: 28821241 [PubMed - indexed for MEDLINE]

Origins of the current seventh cholera pandemic.

March 31, 2018
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Origins of the current seventh cholera pandemic.

Proc Natl Acad Sci U S A. 2016 11 29;113(48):E7730-E7739

Authors: Hu D, Liu B, Feng L, Ding P, Guo X, Wang M, Cao B, Reeves PR, Wang L

Abstract
Vibrio cholerae has caused seven cholera pandemics since 1817, imposing terror on much of the world, but bacterial strains are currently only available for the sixth and seventh pandemics. The El Tor biotype seventh pandemic began in 1961 in Indonesia, but did not originate directly from the classical biotype sixth-pandemic strain. Previous studies focused mainly on the spread of the seventh pandemic after 1970. Here, we analyze in unprecedented detail the origin, evolution, and transition to pandemicity of the seventh-pandemic strain. We used high-resolution comparative genomic analysis of strains collected from 1930 to 1964, covering the evolution from the first available El Tor biotype strain to the start of the seventh pandemic. We define six stages leading to the pandemic strain and reveal all key events. The seventh pandemic originated from a nonpathogenic strain in the Middle East, first observed in 1897. It subsequently underwent explosive diversification, including the spawning of the pandemic lineage. This rapid diversification suggests that, when first observed, the strain had only recently arrived in the Middle East, possibly from the Asian homeland of cholera. The lineage migrated to Makassar, Indonesia, where it gained the important virulence-associated elements Vibrio seventh pandemic island I (VSP-I), VSP-II, and El Tor type cholera toxin prophage by 1954, and it then became pandemic in 1961 after only 12 additional mutations. Our data indicate that specific niches in the Middle East and Makassar were important in generating the pandemic strain by providing gene sources and the driving forces for genetic events.

PMID: 27849586 [PubMed - indexed for MEDLINE]

Prevalence and direct costs of emergency department visits and hospitalizations for selected diseases that can be transmitted by water, United States.

March 30, 2018
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Prevalence and direct costs of emergency department visits and hospitalizations for selected diseases that can be transmitted by water, United States.

J Water Health. 2017 Oct;15(5):673-683

Authors: Adam EA, Collier SA, Fullerton KE, Gargano JW, Beach MJ

Abstract
National emergency department (ED) visit prevalence and costs for selected diseases that can be transmitted by water were estimated using large healthcare databases (acute otitis externa, campylobacteriosis, cryptosporidiosis, Escherichia coli infection, free-living ameba infection, giardiasis, hepatitis A virus (HAV) infection, Legionnaires' disease, nontuberculous mycobacterial (NTM) infection, Pseudomonas-related pneumonia or septicemia, salmonellosis, shigellosis, and vibriosis or cholera). An estimated 477,000 annual ED visits (95% CI: 459,000-494,000) were documented, with 21% (n = 101,000, 95% CI: 97,000-105,000) resulting in immediate hospital admission. The remaining 376,000 annual treat-and-release ED visits (95% CI: 361,000-390,000) resulted in $194 million in annual direct costs. Most treat-and-release ED visits (97%) and costs ($178 million/year) were associated with acute otitis externa. HAV ($5.5 million), NTM ($2.3 million), and salmonellosis ($2.2 million) were associated with next highest total costs. Cryptosporidiosis ($2,035), campylobacteriosis ($1,783), and NTM ($1,709) had the highest mean costs per treat-and-release ED visit. Overall, the annual hospitalization and treat-and-release ED visit costs associated with the selected diseases totaled $3.8 billion. As most of these diseases are not solely transmitted by water, an attribution process is needed as a next step to determine the proportion of these visits and costs attributable to waterborne transmission.

PMID: 29040071 [PubMed - indexed for MEDLINE]

Antibiotic Susceptibility of Non-Cholera Vibrios Isolated from Farmed and Wild Marine Fish (Argyrosomus japonicus), Implications for Public Health.

March 24, 2018

Antibiotic Susceptibility of Non-Cholera Vibrios Isolated from Farmed and Wild Marine Fish (Argyrosomus japonicus), Implications for Public Health.

Microb Drug Resist. 2018 Mar 22;:

Authors: Fri J, Ndip RN, Njom HA, Clarke AM

Abstract
This study aimed to evaluate the antibiogram and antibiotic resistance genes (ARGs) of Vibrio isolates recovered from a marine fish (Argyrosomus japonicus) and water samples from two commercial dusky kob aquaculture farms and the Kariega estuary, South Africa, and to evaluate these findings for their public health implications. A total of 277 molecularly confirmed Vibrio isolates consisting of 126 Vibrio fluvialis, 45 Vibrio vulnificus, 30 Vibrio Parahaemolyticus, and 76 vibrios belonging to species of the genus other than Vibrio cholerae were subjected to susceptibility testing to 15 antibiotics by the disc diffusion method. Multiple antibiotic resistance index (MARI) was used to determine the antibiotic resistance-associated health risk, while polymerase chain reaction was used to evaluate the presence of 14 ARGs for nonsusceptible strains. Highest resistances were recorded to amoxicillin (76.2%), ampicillin (67.5%), erythromycin (38.3%), and doxycycline (35.0%), while susceptibilities were highest to gentamicin (100%), followed by norfloxacin (97.8%), florfenicol (90.3%), tetracycline (87.7%), and chloramphenicol (87.4%). We recorded a 58.5% multidrug resistance (resistance to ≥2 antimicrobial classes). MARI did not vary significantly between sites (p > 0.05); however, values of >0.2 were recorded in 40% (108/277) of all strains tested. ARG markers, ampC, blaOXA, tetA, tetM, dfr1, sul1, sul2, ermB, nptII, strA, and SXT integrase, were detected in one or more strains with ermB (82.5%), sul2 (53.8%), strA (44%), dfr1 (42.3%), and tetM (38.3%) being the most abundant. Healthy marine finfish (dusky kob) and their environment can serve as reservoirs for antibiotic resistant vibrios and ARGs, which could be disseminated to humans and other susceptible bacteria and this therefore becomes a public health concern.

PMID: 29565731 [PubMed - as supplied by publisher]

Efficacy of a single-dose regimen of inactivated whole-cell oral cholera vaccine: results from 2 years of follow-up of a randomised trial.

March 20, 2018
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Efficacy of a single-dose regimen of inactivated whole-cell oral cholera vaccine: results from 2 years of follow-up of a randomised trial.

Lancet Infect Dis. 2018 Mar 14;:

Authors: Qadri F, Ali M, Lynch J, Chowdhury F, Khan AI, Wierzba TF, Excler JL, Saha A, Islam MT, Begum YA, Bhuiyan TR, Khanam F, Chowdhury MI, Khan IA, Kabir A, Riaz BK, Akter A, Khan A, Asaduzzaman M, Kim DR, Siddik AU, Saha NC, Cravioto A, Singh AP, Clemens JD

Abstract
BACKGROUND: A single-dose regimen of inactivated whole-cell oral cholera vaccine (OCV) is attractive because it reduces logistical challenges for vaccination and could enable more people to be vaccinated. Previously, we reported the efficacy of a single dose of an OCV vaccine during the 6 months following dosing. Herein, we report the results of 2 years of follow-up.
METHODS: In this placebo-controlled, double-blind trial done in Dhaka, Bangladesh, individuals aged 1 year or older with no history of receipt of OCV were randomly assigned to receive a single dose of inactivated OCV or oral placebo. The primary endpoint was a confirmed episode of non-bloody diarrhoea for which the onset was at least 7 days after dosing and a faecal culture was positive for Vibrio cholerae O1 or O139. Passive surveillance for diarrhoea was done in 13 hospitals or major clinics located in or near the study area for 2 years after the last administered dose. We assessed the protective efficacy of the OCV against culture-confirmed cholera occurring 7-730 days after dosing with both crude and multivariable per-protocol analyses. This trial is registered at ClinicalTrials.gov, number NCT02027207.
FINDINGS: Between Jan 10, 2014, and Feb 4, 2014, 205 513 people were randomly assigned to receive either vaccine or placebo, of whom 204 700 (102 552 vaccine recipients and 102 148 placebo recipients) were included in the per-protocol analysis. 287 first episodes of cholera (109 among vaccine recipients and 178 among placebo recipients) were detected during the 2-year follow-up; 138 of these episodes (46 in vaccine recipients and 92 in placebo recipients) were associated with severe dehydration. The overall incidence rates of initial cholera episodes were 0·22 (95% CI 0·18 to 0·27) per 100 000 person-days in vaccine recipients versus 0·36 (0·31 to 0·42) per 100 000 person-days in placebo recipients (adjusted protective efficacy 39%, 95% CI 23 to 52). The overall incidence of severe cholera was 0·09 (0·07 to 0·12) per 100 000 person-days versus 0·19 (0·15 to 0·23; adjusted protective efficacy 50%, 29 to 65). Vaccine protective efficacy was 52% (8 to 75) against all cholera episodes and 71% (27 to 88) against severe cholera episodes in participants aged 5 years to younger than 15 years. For participants aged 15 years or older, vaccine protective efficacy was 59% (42 to 71) against all cholera episodes and 59% (35 to 74) against severe cholera. The protection in the older age groups was sustained throughout the 2-year follow-up. In participants younger than 5 years, the vaccine did not show protection against either all cholera episodes (protective efficacy -13%, -68 to 25) or severe cholera episodes (-44%, -220 to 35).
INTERPRETATION: A single dose of the inactivated whole-cell OCV offered protection to older children and adults that was sustained for at least 2 years. The absence of protection of young children might reflect a lesser degree of pre-existing natural immunity in this age group.
FUNDING: Bill & Melinda Gates Foundation to the International Vaccine Institute.

PMID: 29550406 [PubMed - as supplied by publisher]

Aspects on the history of transmission and favor of distribution of viruses by iatrogenic action: perhaps an example of a paradigm of the worldwide spread of HIV.

March 20, 2018
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Aspects on the history of transmission and favor of distribution of viruses by iatrogenic action: perhaps an example of a paradigm of the worldwide spread of HIV.

Med Microbiol Immunol. 2017 Aug;206(4):287-293

Authors: Gürtler LG, Eberle J

Abstract
Transmission of infectious agents might be associated with iatrogenic actions of charitable help in health care. An example is the vaccination against yellow fever in USA that transmitted hepatitis B virus. Another example is injections of praziquantel for treatment and cure of schistosomiasis in Central and Northern Africa, with a focus in Egypt that has spread hepatitis C virus. There is no indication that human T-lymphotropic virus type 1 was spread by injection treatment for African trypanosomiasis, syphilis and treponematosis, but these treatments might have contributed to the early spread of human immunodeficiency virus type 1 (HIV-1) in Central Africa. Slave trade contributed as well to the spread of viruses from Africa to the Americas; it was stopped in 1850. Until that date HIV-1 was not transported to the Americas. By analysis of nucleic acid sequence data it can be concluded that the continental spread of HCV and HIV-1 might have started around 1920 with an exponential phase from 1940 to 1970. Further iatrogenic actions that promoted the spread of HCV and HIV-1 might be vaccinations to prevent deadly diseases. The successful vaccination was followed by diminution of the infectious agent in the population such as small pox, yellow fever and measles. Measurements to reduce the spread of plague and cholera were further benefits increasing survival of diseased subjects in a population. Thus, the reduction of exposure to deadly infectious agents might have given a chance to HIV-1 infected subjects to survive and for HIV-1 to be distributed around the world starting from Central Africa in the 1950s.

PMID: 28434128 [PubMed - indexed for MEDLINE]

Factors associated with cholera in Kenya, 2008-2013.

March 14, 2018
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Factors associated with cholera in Kenya, 2008-2013.

Pan Afr Med J. 2017;28:101

Authors: Cowman G, Otipo S, Njeru I, Achia T, Thirumurthy H, Bartram J, Kioko J

Abstract
Introduction: Kenya experienced widespread cholera outbreaks in 1997-1999 and 2007-2010. The re-emergence of cholera in Kenya in 2015 indicates that cholera remains a public health threat. Understanding past outbreaks is important for preventing future outbreaks. This study investigated the relationship between cholera occurrence in Kenya and various environmental and demographic factors related to water, sanitation, socio-economic status, education, urbanization and availability of health facilities during the time period 2008-2013.
Methods: The primary outcome analyzed was the number of cholera cases at the district level, obtained from the Kenya Ministry of Health's national cholera surveillance records. Values of independent variables were obtained from the 2009 Kenya Population and Housing Census and other national surveys. The data were analyzed using a zero-inflated negative binomial regression model.
Results: Multivariate analysis indicated that the risk of cholera was associated with open defecation, use of unimproved water sources, poverty headcount ratio and the number of health facilities per 100,000 population (p < 0.05). No statistically significant association was found between cholera occurrence and education, percentage of population living in urban areas or population density.
Conclusion: The Sustainable Development Goals and Kenya's blueprint for development, Kenya Vision 2030, call for access to sanitation facilities and clean water for all by 2030. Kenya has made important economic strides in recent years but continues to be affected by diseases like cholera that are associated with low socio-economic status. Further expansion of access to sanitation facilities and clean water is necessary for preventing cholera in Kenya.

PMID: 29515719 [PubMed - indexed for MEDLINE]

Delivering at the country level: the International Coordinating Group on Vaccine Provision and its impact in 2016 and 2017.

March 13, 2018
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Delivering at the country level: the International Coordinating Group on Vaccine Provision and its impact in 2016 and 2017.

Wkly Epidemiol Rec. 2018 Mar 09;93(10):105-16

Authors:

PMID: 29521081 [PubMed - indexed for MEDLINE]

Mapping the burden of cholera in sub-Saharan Africa and implications for control: an analysis of data across geographical scales.

March 6, 2018
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Mapping the burden of cholera in sub-Saharan Africa and implications for control: an analysis of data across geographical scales.

Lancet. 2018 Mar 01;:

Authors: Lessler J, Moore SM, Luquero FJ, McKay HS, Grais R, Henkens M, Mengel M, Dunoyer J, M'bangombe M, Lee EC, Djingarey MH, Sudre B, Bompangue D, Fraser RSM, Abubakar A, Perea W, Legros D, Azman AS

Abstract
BACKGROUND: Cholera remains a persistent health problem in sub-Saharan Africa and worldwide. Cholera can be controlled through appropriate water and sanitation, or by oral cholera vaccination, which provides transient (∼3 years) protection, although vaccine supplies remain scarce. We aimed to map cholera burden in sub-Saharan Africa and assess how geographical targeting could lead to more efficient interventions.
METHODS: We combined information on cholera incidence in sub-Saharan Africa (excluding Djibouti and Eritrea) from 2010 to 2016 from datasets from WHO, Médecins Sans Frontières, ProMED, ReliefWeb, ministries of health, and the scientific literature. We divided the study region into 20 km × 20 km grid cells and modelled annual cholera incidence in each grid cell assuming a Poisson process adjusted for covariates and spatially correlated random effects. We combined these findings with data on population distribution to estimate the number of people living in areas of high cholera incidence (>1 case per 1000 people per year). We further estimated the reduction in cholera incidence that could be achieved by targeting cholera prevention and control interventions at areas of high cholera incidence.
FINDINGS: We included 279 datasets covering 2283 locations in our analyses. In sub-Saharan Africa (excluding Djibouti and Eritrea), a mean of 141 918 cholera cases (95% credible interval [CrI] 141 538-146 505) were reported per year. 4·0% (95% CrI 1·7-16·8) of districts, home to 87·2 million people (95% CrI 60·3 million to 118·9 million), have high cholera incidence. By focusing on the highest incidence districts first, effective targeted interventions could eliminate 50% of the region's cholera by covering 35·3 million people (95% CrI 26·3 million to 62·0 million), which is less than 4% of the total population.
INTERPRETATION: Although cholera occurs throughout sub-Saharan Africa, its highest incidence is concentrated in a small proportion of the continent. Prioritising high-risk areas could substantially increase the efficiency of cholera control programmes.
FUNDING: The Bill & Melinda Gates Foundation.

PMID: 29502905 [PubMed - as supplied by publisher]

Alkaline peptone water enrichment with a dipstick test to quickly detect and monitor cholera outbreaks.

March 6, 2018
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Alkaline peptone water enrichment with a dipstick test to quickly detect and monitor cholera outbreaks.

BMC Infect Dis. 2017 11 21;17(1):726

Authors: Bwire G, Orach CG, Abdallah D, Debes AK, Kagirita A, Ram M, Sack DA

Abstract
BACKGROUND: Detection, confirmation and monitoring of cholera outbreaks in many developing countries including Uganda is a big challenge due to lack of the required resources and the time the test takes. Culture method which takes 24-48 h to get the feedback and requires highly skilled laboratory staff plus other complex resources is the standard test. This study evaluated the new cholera rapid detection method that relies on Crystal VC dipsticks after enrichment with alkaline peptone water (APW) against the culture method for monitoring the progress of cholera outbreaks in rural setting.
METHODS: We conducted the study between March and June 2015. Fresh stool samples and rectal swabs were incubated in 1% APW for 6 h at room temperature before testing with RDT following the manufacturer's instruction. The same stool sample was cultured to isolate V. cholerae in the standard manner. We also reviewed patient registers to epidemiologically describe the cholera epidemic.
RESULTS: We tested stool from 102 consenting suspected cholera patients reporting during daytime at Bwera Hospital (n = 69), Kilembe Mines Hospital (n = 4) and Kinyabwama Health Centre (n = 29). Ninety one (91) samples were positive and nine samples were negative according to both methods. One (1) sample was positive only by dipstick and one sample was positive only by culture (sensitivity of 99%, specificity of 90%, Positive Predictive Value of 99% and Negative Predictive Value of 90%). Overall, 146 suspected cholera cases and two deaths, (case fatality rate of 1.36%) were recorded during the study period. Among the cases aged 1-9 years, 63% (50/79) were males while in those aged 20-49 years, 76% (34/45) were females.
CONCLUSIONS: Our findings showed that the modified dipstick test after enrichment with 1% APW had high level of accuracy in detection of V. cholerae and is quick, affordable alternative cholera outbreak monitoring tool in resource constrained settings. However, culture method should remain for cholera epidemic confirmation, for monitoring of antibiotic sensitivity and for production of pure isolates for molecular characterization. Further studies should be done to better understand the observed age and sex case distribution, in Kasese district.

PMID: 29157211 [PubMed - indexed for MEDLINE]

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