Outbreak In Haiti Research Articles

Rainfall mediations in the spreading of epidemic cholera

Following the empirical evidence of a clear correlation between rainfall events and cholera resurgence that was observed in particular during the recent outbreak in Haiti, a spatially explicit model of epidemic cholera is re-examined. Specifically, we test a multivariate Poisson rainfall generator, with parameters varying in space and time, as a driver of enhanced disease transmission. The relevance of the issue relates to the key insight that predictive mathematical models may provide into the course of an ongoing cholera epidemic aiding emergency management (say, in allocating life-saving supplies or health care staff) or in evaluating alternative management strategies. Our model consists of a set of dynamical equations (SIRB-like i.e. subdivided into the compartments of Susceptible, Infected and Recovered individuals, and including a balance of Bacterial concentrations in the water reservoir) describing a connected network of human communities where the infection results from the exposure to excess concentrations of pathogens in the water. These, in turn, are driven by rainfall washout of open-air defecation sites or cesspool overflows, hydrologic transport through waterways and by mobility of susceptible and infected individuals. We perform an a posteriori analysis (from the beginning of the epidemic in October 2010 until December 2011) to test the model reliability in predicting cholera cases and in testing control measures, involving vaccination and sanitation campaigns, for the ongoing epidemic. Even though predicting reliably the timing of the epidemic resurgence proves difficult due to rainfall inter-annual variability, we find that the model can reasonably quantify the total number of reported infection cases in the selected time-span. We then run a multi-seasonal prediction of the course of the epidemic until December 2015, to investigate conditions for further resurgences and endemicity of cholera in the region with a view to policies which may bring to the eradication of the disease in Haiti. The projections, although strongly depending on still uncertain epidemiological processes, show an endemic, seasonal pattern establishing in the region, which can be better forestalled by an improvement of the sanitation system only, rather than by vaccination alone. We thus conclude that hydrologic drivers and water resources management prove central to prediction, emergency management and long-term control of epidemic cholera.

Borders, buscones, brothels, and bi-national markets: Haitian women negotiate how to get through

The 2010 earthquake and cholera outbreak in Haiti have given a push to women’s migration to the Dominican Republic, and risk of being trafficked. Employing a feminist ethnographic approach, this case study examines the experiences of Haitian women and girls in the Dominican border town of Comendador, Elías Piña, to understand the choices and calculated risks they take in order to “get through.” The authors situate trafficking within a spectrum of violence against women along a border marked by radically asymmetrical power relations, and call for coordinated social interventions beyond law enforcement that guarantee effective protection in the cross-border context.

Clinical Isolates of Vibrio cholerae O1 El Tor Ogawa of 2009 from Kolkata, India: Preponderance of SXT Element and Presence of Haitian ctxB Variant

BackgroundIncrease in the number of multidrug resistant pathogens and the accompanied rise in case fatality rates has hampered the treatment of many infectious diseases including cholera. Unraveling the mechanisms responsible for multidrug resistance in the clinical isolates of Vibrio cholerae would help in understanding evolution of these pathogenic bacteria and their epidemic potential. This study was carried out to identify genetic factors responsible for multiple drug resistance in clinical isolates of Vibrio cholerae O1, serotype Ogawa, biotype El Tor isolated from the patients admitted to the Infectious Diseases Hospital, Kolkata, India, in 2009.Methodology/Principal FindingsOne hundred and nineteen clinical isolates of V. cholerae were analysed for their antibiotic resistance phenotypes. Antibiogram analysis revealed that majority of the isolates showed resistance to co-trimoxazole, nalidixic acid, polymixin B and streptomycin. In PCR, SXT integrase was detected in 117 isolates and its sequence showed 99% identity notably to ICEVchInd5 from Sevagram, India, ICEVchBan5 from Bangladesh and VC1786ICE sequence from Haiti outbreak among others. Antibiotic resistance traits corresponding to SXT element were transferred from the parent Vibrio isolate to the recipient E. coli XL-1 Blue cells during conjugation. Double-mismatch-amplification mutation assay (DMAMA) revealed the presence of Haitian type ctxB allele of genotype 7 in 55 isolates and the classical ctxB allele of genotype 1 in 59 isolates. Analysis of topoisomerase sequences revealed the presence of mutation Ser83 → Ile in gyrA and Ser85→ Leu in parC. This clearly showed the circulation of SXT-containing V. cholerae as causative agent for cholera in Kolkata.ConclusionsThere was predominance of SXT element in these clinical isolates from Kolkata region which also accounted for their antibiotic resistance phenotype typical of this element. DMAMA PCR showed them to be a mixture of isolates with different ctxB alleles like classical, El Tor and Haitian variants.

The Origin of Cholera in Haiti

Ten months after a devastating earthquake on January 12, 2010, cholera appeared in Haiti for the first time in nearly a century. The secretary-general of the United Nations formed an independent panel to “investigate and seek to determine the source of the 2010 cholera outbreak in Haiti.” To fulfill this mandate, concurrent epidemiological, water and sanitation, and analysis of molecular investigations were carried out. Our findings indicated that the 2010 Haiti cholera outbreak was caused by bacteria introduced to Haiti as a result of human activity, specifically, by contamination of the Meye tributary system of the Artibonite River by a pathogenic strain of current South Asian Vibrio cholerae. Recommendations were presented to assist in preventing the future introduction and spread of cholera. The use of concurrent epidemiological, water and sanitation, and molecular analysis is recommended to public health professionals for future cholera investigations.

BiotecVisions 2012, November

BiotecVisions 2012, November

Considerations for Oral Cholera Vaccine Use during Outbreak after Earthquake in Haiti, 2010–2011

Considerations for Oral Cholera Vaccine Use during Outbreak after Earthquake in Haiti, 2010–2011

Is A Universal, One Dose Cholera Vaccine Possible?

The Gram negative bacterium, Vibrio cholerae (Vc) causes cholera, an enteric disease that has killed untold numbers of humans. In the 19 th century, whole-cell (W-C) cholera vaccines were tested in humans. Field trials (1960s- 70s) of injected, killed W-C (kW-C) Vc showed cholera-specific immune responses (antibodies, Abs) could be induced with a single dose in certain cohorts, but more durable immunity was sought with oral cholera vaccines. Newer, killed (two doses) and later modified live (one dose) W-C cholera vaccines for oral delivery were developed and extensively tested. After over 200 years, no consensus exists as to what are protective Vc antigens or how to identify them. An endur- ing cholera vaccine for children <5 years of age and Vc-antigen naive individuals is still needed. The cholera outbreak in Haiti underscores some unresolved issues associated with the current cholera vaccines. Annually, is there enough cholera vaccine for those who need it? Who needs to be vaccinated and when? Given the displacement of populations during flooding like in Pakistan or in Haiti due to an earthquake, can a single dose of the kW-C cholera vaccine function to pre- vent or to contain an outbreak? What does 'working' entail: solely preventing deaths, or that plus long term immunity? Can a single formulation of Vc antigens be used for endemic or epidemic cholera which may require reactive vaccination for epidemics, but prophylactic vaccination for endemic cholera? The immunologic realities given the logistic issues for the different needs of a cholera vaccine are discussed.

Preparing Health Care Workers for a Cholera Epidemic, Dominican Republic, 2010

Preparing Health Care Workers for a Cholera Epidemic, Dominican Republic, 2010

Vaccination of travelers: how far have we come and where are we going?

Vaccine recommendations are a prominent part of health preparations before international travel. We review progress made in the past decade regarding vaccines used primarily by persons traveling from high-income countries to low- and middle-income countries. The combined hepatitis A–B vaccine, the recently licensed Vero cell-derived Japanese encephalitis vaccine and conjugated quadrivalent meningococcal vaccines are discussed. This article provides updates on yellow fever vaccine-associated visceral and neurologic adverse events, indications for influenza vaccine in travelers, the rapid immunization schedule for tick-borne encephalitis vaccine, schedules for postexposure rabies prophylaxis, and new insights about oral cholera vaccines following the outbreak in Haiti. The future should bring vaccines for serogroup B Neiserria meningitidis, dengue and malaria, as well as an inactivated yellow fever vaccine.

Academic Consortia: Untapped Resources for Preparedness, Response, and Recovery—Examining the Cholera Outbreak in Haiti

Academic Consortia: Untapped Resources for Preparedness, Response, and Recovery—Examining the Cholera Outbreak in Haiti

Comparative Genomics of Vibrio cholerae from Haiti, Asia, and Africa

Cholera was absent from the island of Hispaniola at least a century before an outbreak that began in Haiti in the fall of 2010. Pulsed-field gel electrophoresis (PFGE) analysis of clinical isolates from the Haiti outbreak and recent global travelers returning to the United States showed indistinguishable PFGE fingerprints. To better explore the genetic ancestry of the Haiti outbreak strain, we acquired 23 whole-genome Vibrio cholerae sequences: 9 isolates obtained in Haiti or the Dominican Republic, 12 PFGE pattern-matched isolates linked to Asia or Africa, and 2 nonmatched outliers from the Western Hemisphere. Phylogenies for whole-genome sequences and core genome single-nucleotide polymorphisms showed that the Haiti outbreak strain is genetically related to strains originating in India and Cameroon. However, because no identical genetic match was found among sequenced contemporary isolates, a definitive genetic origin for the outbreak in Haiti remains speculative.

Toxigenic Vibrio cholerae O1 in Water and Seafood, Haiti

During the 2010 cholera outbreak in Haiti, water and seafood samples were collected to detect Vibrio cholerae. The outbreak strain of toxigenic V. cholerae O1 serotype Ogawa was isolated from freshwater and seafood samples. The cholera toxin gene was detected in harbor water samples.

Population Genetics of Vibrio cholerae from Nepal in 2010: Evidence on the Origin of the Haitian Outbreak

ABSTRACTCholera continues to be an important cause of human infections, and outbreaks are often observed after natural disasters, such as the one following the 2010 earthquake in Haiti. Once the cholera outbreak was confirmed, rumors spread that the disease was brought to Haiti by a battalion of Nepalese soldiers serving as United Nations peacekeepers. This possible connection has never been confirmed. We used whole-genome sequence typing (WGST), pulsed-field gel electrophoresis (PFGE), and antimicrobial susceptibility testing to characterize 24 recent Vibrio cholerae isolates from Nepal and evaluate the suggested epidemiological link with the Haitian outbreak. The isolates were obtained from 30 July to 1 November 2010 from five different districts in Nepal. We compared the 24 genomes to 10 previously sequenced V. cholerae isolates, including 3 from the Haitian outbreak (began July 2010). Antimicrobial susceptibility and PFGE patterns were consistent with an epidemiological link between the isolates from Nepal and Haiti. WGST showed that all 24 V. cholerae isolates from Nepal belonged to a single monophyletic group that also contained isolates from Bangladesh and Haiti. The Nepalese isolates were divided into four closely related clusters. One cluster contained three Nepalese isolates and three Haitian isolates that were almost identical, with only 1- or 2-bp differences. Results in this study are consistent with Nepal as the origin of the Haitian outbreak. This highlights how rapidly infectious diseases might be transmitted globally through international travel and how public health officials need advanced molecular tools along with standard epidemiological analyses to quickly determine the sources of outbreaks.

Genetic Screens and Biochemical Assays to Characterize Vibrio cholerae O1 Biotypes: Classical and El Tor.

Vibrio cholerae serogroup O1 has two biotypes, classical and El Tor, the latter of which has displaced the prior and has been the causative agent for the ongoing seventh pandemic. However, reports since 2001 have identified clinical isolates of El Tor that have classical O1 biotype genetic and phenotypic characteristics. These El Tor variants have been emerging in clinical settings with increased frequency, including the 2010 cholera outbreak in Haiti. The emergence of El Tor variants warrants the proper and timely identification of clinical (or environmental) isolates' biotype. This unit describes some quick and simple genetic screens and phenotypic assays (biochemical characterization), to be performed simultaneously, commonly used to distinguish biotype and initiate characterization of any clinical (or environmental) isolates of Vibrio cholerae O1.

Community beliefs and fears during a cholera outbreak in Haiti

Community beliefs and fears during a cholera outbreak in Haiti

Despite Sensitivities, Scientists Seek to Solve Haiti's Cholera Riddle

Several cholera experts have told Science that nailing the source of the recent cholera outbreak in Haiti could potentially embarrass the United Nations, distract from the day-to-day fight to control the outbreak, and even lead to violence.

Lack of clean water exacerbates cholera outbreak in Haiti

<h3>Abstract</h3> <h3>Background</h3> Congenital heart disease (CHD) affecting the conotruncal region of the heart, occur in half of patients with 22q11.2 deletion syndrome. This syndrome is a rare disorder with relative genetic homogeneity that can facilitate identification of genetic modifiers. Haploinsufficiency of <i>TBX1</i>, mapped to the 22q11.2 region, encoding a T-box transcription factor, is one of the main genes for the etiology of the syndrome. We suggest that genetic modifiers of CHD in patients with 22q11.2 deletion syndrome may be in the <i>TBX1</i> gene network. <h3>Methods</h3> To identify genetic modifiers of 22q11.2 deletion syndrome, we analyzed whole genome sequence of subjects with 22q11.2DS, of which 456 were cases with conotruncal heart defects and 537 were controls with normal cardiac structures. We retained the most damaging rare coding variants and examined 19 functional gene sets for association that were weighted upon expression of genes in cardiac progenitor cells in mouse embryos identified by RNA-sequencing. <h3>Results</h3> We identified rare damaging coding variants in chromatin regulatory genes as modifiers of conotruncal heart defects in 22q11.2DS. Chromatin genes with recurrent damaging variants include <i>EP400, KAT6A, KMT2C, KMT2D, NSD1, CHD7</i> and <i>PHF21A</i>. In total, we identified 37 chromatin regulatory genes, that may increase risk for conotruncal heart defects in 8.5% of 22q11.2 deletion syndrome cases. Many of these genes were identified as risk factors for sporadic CHD in the general population increasing the likelihood that these genes are medically important contributors for CHD. These genes are co-expressed in cardiac progenitor cells with <i>TBX1</i>, suggesting that they may be in the same genetic network. Some of the genes identified, such as <i>KAT6A, KMT2C, CHD7</i> and <i>EZH2</i>, have been previously shown to genetically interact with <i>TBX1</i> in mouse models, providing mechanistic validation of these genes found. <h3>Conclusions</h3> Our findings indicate that disturbance of chromatin regulatory genes impact a <i>TBX1</i> gene network serving as genetic modifiers of 22q11.2 deletion syndrome. Since some of these chromatin regulatory genes were found in individuals with sporadic CHD, we suggest that there are shared mechanisms involving the <i>TBX1</i> gene network in the etiology of CHD.

Haiti's Outbreak Is Latest in Cholera's New Global Assault

Haitian protesters blamed peacekeepers from Nepal after a deadly surprise outbreak of cholera began in Haiti 2 weeks ago, but on Monday, the U.S. Centers for Disease Control and Prevention announced that DNA fingerprinting of the microbes from 13 patients had shown that it was most similar to strains from South Asia.