Recent Cholera Publications on PubMed
Origin and Dissemination of Altered El Tor Vibrio cholerae O1 Causing Cholera in Odisha, India: Two and Half Decade's View
Front Microbiol. 2021 Nov 18;12:757986. doi: 10.3389/fmicb.2021.757986. eCollection 2021.
The origin, spread and molecular epidemiology of altered El Tor Vibrio cholerae O1 strains isolated from cholera outbreaks/surveillance studies between 1995 and 2019 from different district of Odisha were analyzed. The stock cultures of V. cholerae O1 strains from 1995 to 2019 were analyzed through molecular analysis using different PCR assays and pulse field gel electrophoresis (PFGE) analysis. The spread map (month, year and place) was constructed to locate the dissemination of altered El Tor variants of V. cholerae O1 in this region. A total of 13 cholera outbreaks were caused by V. cholerae O1 Ogawa biotype El Tor carrying ctxB1 and ctxB7 genotypes. The ctxB1 alleles of V. cholerae O1 mostly confined to the coastal areas, whereas the ctxB7 genotypes, though originating in the coastal region of Odisha, concentrated more in the tribal areas. The positive correlation between virulence-associated genes (VAGs) was found through Pearson's correlation model, indicative of a stronger association between the VAGs. The clonal relationship through PFGE between ctxB1 and ctxB7 genotypes of V. cholerae O1 strains exhibited 80% similarity indicating single- or multi-clonal evolution. It is evident from this study that the spread of multidrug-resistant V. cholerae O1-altered El Tor was dominant over the prototype El Tor strains in this region. The origin of altered El Tor variants of V. cholerae O1 occurred in the East Coast of Odisha established that the origin of cholera happened in the Gangetic belts of Bay of Bengal where all new variants of V. cholerae O1 might have originated from the Asian countries.
Prevalence of syphilis infection and associated sociodemographic factors among antenatal-care attendees in Meghalaya, India: Revisiting HIV Sentinel Surveillance data
Int J STD AIDS. 2021 Dec 1:9564624211054940. doi: 10.1177/09564624211054940. Online ahead of print.
BACKGROUND: Despite relatively simple prevention and treatment, syphilis remains a major social and public health concern worldwide, particularly in developing nations.
OBJECTIVE: To estimate the prevalence and to determine the sociodemographic factors associated with syphilis infection among antenatal-care (ANC) attendees in Meghalaya, India.
MATERIALS AND METHOD: A facility-based cross-sectional study was conducted utilizing National HIV Sentinel Surveillance of Meghalaya, January-March 2017. Pregnant women aged 15-49 years (n = 3015) were recruited consecutively, interviewed, and tested for syphilis by Venereal Disease Research Laboratory test in eight selected ANC sites representing all districts of Meghalaya.
RESULTS: Prevalence of syphilis was found to be 1.03 % (95% CI = 0.67-1.39) (31/3015). Prevalence was maximum among illiterates with gradual lowering of adjusted odds ratio (AOR) with improvement of education. Women whose husbands had no income were associated with higher risk (AOR = 4.97, 95% CI = 1.11-22.20) of syphilis. Significant risk (OR = 2.42, 95% CI = 1.02-5.74) was also observed with Jaintia Hills residents as compared to Garo Hills.
CONCLUSIONS: As high prevalence of gestational syphilis was identified in Meghalaya along with important sociodemographic predictors, evidence to policy translation is required at state and national level to scale up prevention, screening, and management of syphilis.
Molecular characterization of Vibrio cholerae O1 isolates obtained from outbreaks in the Philippines, 2015-2016
J Med Microbiol. 2021 Nov;70(11). doi: 10.1099/jmm.0.001443.
Introduction. The Philippines, comprising three island groups, namely, Luzon, Visayas and Mindanao, experienced an increase in cholera outbreaks in 2016. Previous studies have shown that Vibrio cholerae isolates obtained from the Philippines are novel hybrid El Tor strains that have evolved in the country and are clearly distinct from those found in Mozambique and Cameroon.Gap statement. The characterization of the strains isolated from outbreaks has been limited to phenotypic characteristics, such as biochemical and serological characteristics, in most previous studies.Aim. We performed multilocus variable-number tandem repeat (VNTR) analysis (MLVA) for V. cholerae isolates obtained from 2015 to 2016 to further characterize and understand the emergence and dissemination of the strains in the Philippines.Methodology. A total of 139 V. cholerae O1 Ogawa biotype El Tor isolates were obtained from the Philippines during diarrhoeal outbreaks in 18 provinces between 2015 and 2016. VNTR data were analysed to classify the MLVA profiles where the large-chromosome types (LCTs) were applied for grouping.Results. We identified 50 MLVA types among 139 isolates originating from 18 provinces, and 14 LCTs. The distribution of the LCTs was variable, and a few were located in specific areas or even in specific provinces. Based on eBURST analysis, 99 isolates with 7 LCTs and 32 MLVA types belonged to 1 group, suggesting that they were related to each other. LCT A was predominant (n=67) and was isolated from Luzon and Visayas. LCT A had 14 MLVA types; however, it mostly emerged during a single quarter of a year. Eight clusters were identified, each of which involved specific MLVA type(s). The largest cluster involved 23 isolates showing 3 MLVA types, 21 of which were MLVA type A-14 isolated from Negros Occidental during quarter 4 of 2016. Comparative analysis showed that almost all isolates from the Philippines were distinct from those in other countries.Conclusions. The genotypic relationship of the V. cholerae isolates obtained during outbreaks in the Philippines was studied, and their emergence and dissemination were elucidated. MLVA revealed the short-term dynamics of V. cholerae genotypes in the Philippines.
Exploring relationships between drought and epidemic cholera in Africa using generalised linear models
BMC Infect Dis. 2021 Nov 22;21(1):1177. doi: 10.1186/s12879-021-06856-4.
BACKGROUND: Temperature and precipitation are known to affect Vibrio cholerae outbreaks. Despite this, the impact of drought on outbreaks has been largely understudied. Africa is both drought and cholera prone and more research is needed in Africa to understand cholera dynamics in relation to drought.
METHODS: Here, we analyse a range of environmental and socioeconomic covariates and fit generalised linear models to publicly available national data, to test for associations with several indices of drought and make cholera outbreak projections to 2070 under three scenarios of global change, reflecting varying trajectories of CO2 emissions, socio-economic development, and population growth.
RESULTS: The best-fit model implies that drought is a significant risk factor for African cholera outbreaks, alongside positive effects of population, temperature and poverty and a negative effect of freshwater withdrawal. The projections show that following stringent emissions pathways and expanding sustainable development may reduce cholera outbreak occurrence in Africa, although these changes were spatially heterogeneous.
CONCLUSIONS: Despite an effect of drought in explaining recent cholera outbreaks, future projections highlighted the potential for sustainable development gains to offset drought-related impacts on cholera risk. Future work should build on this research investigating the impacts of drought on cholera on a finer spatial scale and potential non-linear relationships, especially in high-burden countries which saw little cholera change in the scenario analysis.
Antimicrobial effect of Moringa oleifera seed powder against Vibrio cholerae isolated from the rearing water of shrimp (Penaeus vannamei) postlarvae
Lett Appl Microbiol. 2021 Nov 22. doi: 10.1111/lam.13604. Online ahead of print.
Shrimp farming has experienced rising costs as a result of disease outbreaks associated with Vibrio spp. Suitable strategies for disease prevention and control are therefore urgently needed. This study aimed to evaluate the antimicrobial effect of Moringa oleifera seed powder against Vibrio cholerae in the rearing water of Pacific white shrimp (Penaeus vannamei) postlarvae. In vitro assays included the determination of minimum inhibitory concentration (MIC) of M. oleifera seed powder against V. cholerae, whereas in vivo assays included the effect of M. oleifera seed powder on bacterial load and water quality parameters in the rearing tanks, as well as its effect on shrimp postlarvae survival. M. oleifera seed powder inhibited the growth of V. cholerae with MIC values of 62.5 µg/mL. Moreover, seawater pH of treated tanks (8.66) was significantly lower (p<0.01) than pH of the control tanks (9.02), whereas the visibility of treated tanks (37.08 cm) was significantly higher (p<0.01) as compared to control tanks (35.37 cm). Likewise, V. cholerae load was significantly reduced (p<0.01) from 4.7×104 to 3.1×103 CFU/mL in tanks treated with M. oleifera seed powder. Altogether, this study demonstrates the antimicrobial activity of M. oleifera against V. cholerae in shrimp culture.
Survey of water supply and assessment of groundwater quality in the suburban communes of Selembao and Kimbanseke, Kinshasa in Democratic Republic of the Congo
Sustain Water Resour Manag. 2022;8(1):3. doi: 10.1007/s40899-021-00592-y. Epub 2021 Nov 10.
In many suburban municipalities of developing countries, the household drinking water comes mainly from groundwater including, wells, streams and springs. These sources are vulnerable because poor hygienic conditions and sanitation prevail causing persistence and recurrent waterborne diseases. In this research, a survey study on water resource use and an epidemiological survey of waterborne diseases were conducted among users of water points and medical institutions in suburban communes of Selembao and Kimbanseke (Kinshasa, the Democratic Republic of the Congo). In addition, physicochemical (temperature, pH, O2, electrical conductivity, and soluble ions: Na+, K+, PO4 3-, SO4 2-, NO3 -, NO2 -) and bacteriological (FIB: faecal indicator bacteria) analyses of water from 21 wells and springs were performed according to the seasonal variations. FIB included Escherichia coli (E. coli), Enterococcus and Total Coliforms. The survey results indicate that more than 75% of the patients admitted to local medical institutions between 2016 and 2019 are affected by waterborne diseases, including typhoid fever, amoebic dysentery, diarrhoea, gastroenteritis disorders and cholera. Except for NO3 - in some sites, the water physicochemical parameter values are within WHO permissible limits for drinking/domestic water quality. On the contrary, the results revealed high FIB levels in water from unmanaged wells and springs during rainy and dry seasons. The microbiological pollution was significantly higher in the rainy season compared to the dry season. Interestingly, no FIB contamination was observed in water samples from managed/developed wells. The results from this study will guide local government decisions on improving water quality to prevent recurrent waterborne diseases.
Taking care of a diarrhea epidemic in an urban hospital in Bangladesh: Appraisal of putative causes, presentation, management, and deaths averted
PLoS Negl Trop Dis. 2021 Nov 15;15(11):e0009953. doi: 10.1371/journal.pntd.0009953. Online ahead of print.
BACKGROUND: In April 2018, a diarrhea epidemic broke out in Dhaka city and adjoining areas, which continued through May. The Dhaka Hospital of the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), a dedicated diarrheal disease hospital, had a large upsurge in patient visits during the epidemic. An enhanced understanding of the epidemiology of this epidemic may help health-related professionals better prepare for such events in the future. This study examined the microbial etiology and non-pathogen factors associated with diarrhea during the epidemic. The study also evaluated the patients' presentation and clinical course and estimated the potential mortality averted by treating patients during the epidemic.
METHODOLOGY/PRINCIPAL FINDINGS: Data from the patients who were treated at Dhaka Hospital during the diarrhea epidemic between April 2 and May 12, 2018 and were enrolled into the Diarrheal Disease Surveillance System (DDSS) at icddr,b were compared with the DDSS-enrolled patients treated during the seasonally-matched periods in the flanking years using logistic regression. icddr,b Dhaka Hospital treated 29,212 diarrheal patients during the 2018 epidemic period (and 25,950 patients per comparison period on average). Vibrio cholerae was the most common pathogen isolated (7,946 patients; 27%) and associated with diarrhea during the epidemic (adjusted odds ratio [AOR] 1.5, 95% CI: 1.1-2.0). The interaction of Vibrio cholerae with ETEC (AOR 2.7, 95% CI: 1.3-5.9) or Campylobacter (AOR 2.4, 95% CI: 1.1-5.1) was associated with further increased odds of diarrhea during the epidemic. In children under five years old, rotavirus was the most common pathogen (2,029 patients; 26%). Those who were adolescents (AOR 2.0, 95% CI: 1.3-3.1) and young adults (AOR 1.9, 95% CI: 1.4-2.5) compared to children younger than five years, resided within a 10 km radius of Dhaka Hospital (AOR 1.6, 95% CI: 1.1-2.2) compared to those living outside 20 km, borrowed money or relied on aid to pay for the transport to the hospital (AOR 1.6, 95% CI: 1.2-2.0), used tap water (AOR 1.8, 95% CI: 1.4-2.4) for drinking compared to tubewell water, and disposed of the solid waste directly outside the house (AOR 4.0, 95% CI: 2.7-5.9) were more likely to present with diarrhea during the epidemic. During the epidemic, patients were more likely to present with severe dehydration (odds ratio [OR] 1.6, 95% CI: 1.3-2.0) and require inpatient admission (OR 2.5, 95% CI: 1.9-3.3), intravenous rehydration (OR 1.7, 95% CI: 1.4-2.1), and antibiotics (OR 2.2, 95% CI: 1.8-2.7). The in-hospital case fatality rate was low (13 patients; 0.04%), and the hospital averted between 12,523 and 17,265 deaths during the epidemic.
CONCLUSIONS/SIGNIFICANCE: Vibrio cholerae played the primary role in the 2018 diarrhea epidemic in Dhaka. Campylobacter, enterotoxigenic Escherichia coli, and rotavirus had a secondary role. Adolescents and adults, residents of the metropolitan area, and those who were relatively poor and lacked safe water, sanitation, and hygiene (WASH) practices comprised the most vulnerable groups. Despite the increased disease severity during the epidemic, the case fatality rate was less than 0.1%. icddr,b Dhaka Hospital saved as many as 17,265 lives during the epidemic.
Int J Environ Res Public Health. 2021 Oct 27;18(21):11296. doi: 10.3390/ijerph182111296.
Cholera remains a heavy burden worldwide, especially in Sub-Saharan African countries, which account for the majority of the reported cases on the continent. In this study, a 27-year retrospective analysis of cholera epidemics in Guinea-Bissau was performed in order to highlight major stressors fueling the trigger and dissemination of the disease. Although the role of environmental factors did not always have the same degree of importance for the onset of epidemics, a cholera seasonal pattern was clearly perceived, with most of the reported cases occurring during the wet season. The generated theoretical hypothesis indicated rainfall above climatological average, associated with a lack of WASH (water, sanitation and hygiene) infrastructure, and the occurrence of concomitant epidemics in neighboring countries as the key indicators for optimal conditions for cholera to thrive in Guinea-Bissau. Warmer air temperature, the increase in sea surface temperature, and the decrease in salinity in the coastal areas may also contribute to the emergence and/or aggravation of cholera events. Prediction of the conditions favorable for cholera growth and identification of risk pathways will allow the timely allocation of resources, and support the development of alert tools and mitigation strategies.
The Impact of Meteorological Factors on Communicable Disease Incidence and Its Projection: A Systematic Review
Int J Environ Res Public Health. 2021 Oct 22;18(21):11117. doi: 10.3390/ijerph182111117.
BACKGROUND: Climate change poses a real challenge and has contributed to causing the emergence and re-emergence of many communicable diseases of public health importance. Here, we reviewed scientific studies on the relationship between meteorological factors and the occurrence of dengue, malaria, cholera, and leptospirosis, and synthesized the key findings on communicable disease projection in the event of global warming.
METHOD: This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 flow checklist. Four databases (Web of Science, Ovid MEDLINE, Scopus, EBSCOhost) were searched for articles published from 2005 to 2020. The eligible articles were evaluated using a modified scale of a checklist designed for assessing the quality of ecological studies.
RESULTS: A total of 38 studies were included in the review. Precipitation and temperature were most frequently associated with the selected climate-sensitive communicable diseases. A climate change scenario simulation projected that dengue, malaria, and cholera incidence would increase based on regional climate responses.
CONCLUSION: Precipitation and temperature are important meteorological factors that influence the incidence of climate-sensitive communicable diseases. Future studies need to consider more determinants affecting precipitation and temperature fluctuations for better simulation and prediction of the incidence of climate-sensitive communicable diseases.
Int J Mol Sci. 2021 Oct 28;22(21):11657. doi: 10.3390/ijms222111657.
Approximately 1/6 of humanity is at high risk of experiencing cholera epidemics. The development of effective and safe vaccines against Vibrio cholerae, the primary cause of cholera, is part of the public health measures to prevent cholera epidemics. Natural nontoxigenic V. cholerae isolates represent a source of new genetically improved and relatively safe vaccine strains. However, the genomic engineering of wild-type V. cholerae strains is difficult, and these strains are genetically unstable due to their high homologous recombination activity. We comprehensively characterized two V. cholerae isolates using genome sequencing, bioinformatic analysis, and microscopic, physiological, and biochemical tests. Genetic constructs were Gibson assembled and electrotransformed into V. cholerae. Bacterial colonies were assessed using standard microbiological and immunological techniques. As a result, we created a synthetic chromoprotein-expressing reporter operon. This operon was used to improve the V. cholerae genome engineering approach and monitor the stability of the genetic constructs. Finally, we created a stable candidate V. cholerae vaccine strain bearing a recA deletion and expressing the β-subunit of cholera toxin. Thus, we developed a strategy for the rapid creation of genetically stable and relatively safe candidate vaccine strains. This strategy can be applied not only to V. cholerae but also to other important human bacterial pathogens.
J Med Microbiol. 2021 Nov;70(11). doi: 10.1099/jmm.0.001450.
During the 1854 cholera outbreak in Florence, Italy, Filippo Pacini documented that the cause of the infection was a bacterium. This conclusion was also independently reached by John Snow during the 1854 cholera outbreak in London. By using an epidemiological method, Snow found that the infection spread through a polluted water network. Snow identified a water pump as the source of the disease. After removing the infected handle of this pump, the cases of cholera rapidly began to decrease. A microscopic examination of the water showed organic impurities but no bacteria. This discovery was ignored during Snow's lifetime. In contrast, through microscopy during the autopsies of cholera victims, Pacini observed that the disruption of their intestinal mucosa was closely associated with millions of the bacteria that he called Vibrio cholerae. Via histological techniques, Pacini detected that intestinal mucosa reabsorption dysfunction was the cause of debilitating diarrhoea, vomiting, severe dehydration and death. Nevertheless, his discovery of Vibrio cholerae was ignored during Pacini's lifetime. A survey of Pacini's autographic manuscripts suggests that Pacini and Snow may have shared mutual knowledge within their respective seminal papers. This survey also facilitates, for the first time, the creation of maps that illustrate the worldwide distribution of Pacini's cholera papers from 1854 to 1881. The consistent neglect of Pacini's discovery remains a true enigma.
Rev Esp Salud Publica. 2021 Nov 4;95:e202111185.
BACKGROUND: The humanitarian response to a cholera outbreak in a complex international crisis requires guaranteeing minimum conditions so that normalcy can be restored. Basic responses to a cholera outbreak include water and sanitation. The general objective of this systematic review was the analysis of the current evidence that addresses the effectiveness of different WASH measures to control cholera.
METHODS: A review and analysis of the literature available in the main databases (PubMed, WoS and Scopus) and in a specific meta-search engine for humanitarian aid was carried out (reliefweb.int). Based on the establishment of the PICO research question "Can beneficiaries of humanitarian aid benefit from water, hygiene and sanitation interventions for cholera reduction?", the identification of keywords and databases to carry out the searches, as well as a selection process based on the established eligibility criteria: being studies in both English and Spanish where the WASH intervention was clearly defined, studies where health outcomes of cholera were presented, or data related to the function and use of the WASH intervention, was established.
RESULTS: The initial search provided 17,185 documents susceptible of analysis that were screened using the search criteria, up to 22 references that were read in full text and the 11 that were finally analyzed. These were coded based on the measures set out in their protocols, on the interventions carried out in the improvement of water and its supply, the improvement of sanitation, the measures aimed at better hygiene and those that evaluated the complete WASH intervention.
CONCLUSIONS: All the measures offered positive results, their effectiveness was conditioned by the education of the beneficiaries, the simplicity of the activities and the involvement of local actors.
J Res Health Sci. 2021 Jul 6;21(3):e00522. doi: 10.34172/jrhs.2021.55.
BACKGROUND: On chronic exposure, Lead (Pb) deposits in the skeletal system, replaces calcium ions, and alters the normal physiological processes, which in turn, lead to stunting, delayed fracture healing, and high resorption of collagen molecules. The present study aimed to assess the association of musculoskeletal pain and discomfort with bone turnover markers (BTMs) among long-term Pb-exposed workers.
STUDY DESIGN: A cross-sectional study.
METHODS: The study recruited 176 male Pb-exposed workers and 80 control subjects who were matched for age, gender, and socio-economic status. Blood lead levels (BLLs), bone growth markers, such as serum osteocalcin (OC), alkaline phosphatase (ALP), bone alkaline phosphatase (BAP), and bone resorption markers: serum pyridinoline (Pry), deoxypyridinoline (DPry), tartrate-resistant acid phosphatase-5b(TRACP-5b), and hydroxyproline in urine (HyP-U) of participants were investigated. Pain and discomfort in the musculoskeletal system were assessed using Nordic Musculoskeletal Questionnaire.
RESULTS: Pb-exposure was significantly associated with musculoskeletal discomfort of the lower back (P<0.001), upper back (P<0.001), and ankle/foot (P=0.011). Among bone formation markers, serum OC was significantly lower in musculoskeletal discomfort of elbows (P=0.033) and ankle/foot (P=0.042). Among bone resorption markers, serum DPry was significantly lower in musculoskeletal discomfort of the neck (P=0.049) and shoulders (P=0.023). HyP-U was significantly higher in musculoskeletal discomfort of shoulders (P=0.035) and lower back (P=0.036).
CONCLUSION: As evidenced by the obtained results, Pb-exposure was associated with musculoskeletal discomfort of the lower back, upper back, and ankle/foot. Lower bone formation (serum OC) marker was noted with musculoskeletal discomfort of elbows and ankle/foot. Furthermore, bone resorption markers were associated with musculoskeletal discomfort of the neck, shoulders, and lower back. The findings of the present study suggested that long-term Pb-exposure and BTMs were associated with musculoskeletal discomfort.
Evidence-Based Health Behavior Interventions for Cholera: Lessons from an Outbreak Investigation in India
Am J Trop Med Hyg. 2021 Oct 25:tpmd210625. doi: 10.4269/ajtmh.21-0625. Online ahead of print.
In rural India, since 2014, the Swachh Bharat Abhiyan (Clean India Mission) has ensured construction of more than 100 million toilets and is now focusing on reinforcement of sanitation behaviors. We report a cholera outbreak in a remote village in western India where open defecation was implicated in causation. A water pipeline was damaged in the vicinity of a stream flowing from a site of open defecation. Despite the availability of a toilet facility in the majority of households (75%), open defecation was widely practiced (62.8%). Many reported not washing hands with soap and water before eating (78.5%) and after defecation (61.1%). The study emphasizes the need for focused health behavior studies and evidence-based interventions to reduce the occurrence of cholera outbreaks. This could be the last lap in the path toward achieving Sustainable Development Goal 6, which aims to "ensure availability and sustainable management of water and sanitation for all."
A rare case of severe gastroenteritis caused by Aeromonas hydrophila after colectomy in a patient with anti-Hu syndrome: a case report
BMC Infect Dis. 2021 Oct 24;21(1):1097. doi: 10.1186/s12879-021-06784-3.
BACKGROUND: Aeromonas hydrophila is a gram-negative facultative anaerobic coccobacillus, which is an environmental opportunistic pathogen. A. hydrophila are involved in several infectious diseases such as gastroenteritis, septicemia and wound infections. However, gastroenteritis caused by Aeromonas spp. are rare and the clinical relevance of Aeromonas species in stool specimens is still under debate.
CASE PRESENTATION: Our case concerns a 32-year-old woman who presented at hospital with a worsening watery diarrhea and fever requiring intensive care. A cholera-like illness was diagnosed. The patient had a past history of an anti-Hu syndrome with a myenteric ganglionitis. A molecular multiplex RT-PCR (QIAstat-Dx Gastrointestinal Panel, QIAGEN) covering a broad spectrum of diverse gastrointestinal pathogens performed directly from the stool was negative but the stool culture revealed growth of A. hydrophila. Further investigations of the A. hydrophila strain in cell cultures revealed the presence of a cytotoxic enterotoxin.
CONCLUSIONS: Although A. hydrophila rarely causes gastroenteritis, Aeromonas spp. should be considered as a causative agent of severe gastroenteritis with a cholera-like presentation. This case highlights the need to perform culture methods from stool samples when PCR-based methods are negative and gastrointestinal infection is suspected.
Geospat Health. 2021 Oct 19;16(2). doi: 10.4081/gh.2021.983.
Nineteenth-century London experienced four extraordinarily severe summertime cholera epidemics. Three were preceded by less severe non-summer outbreaks. Twenty-first-century research hypothesizes them as herald waves of potentially new cholera strains. This study examined the geographical characteristics of these herald waves and compared them to their subsequent main waves to determine if there was a geographical component to the significant difference in wave severity. Cholera mortality data for London's parishes and registration districts were extracted from contemporaneous records. The data were normalized and scaled. Each epidemic wave was divided into two segments for analysis. A Spearman's rank correlation was used to assess the relationship between a herald and its subsequent main wave. Geospatial analytical tools were used to determine and display each segment's geographic distribution pattern using autocorrelation techniques to determine its central point. Results show that the herald wave of each epidemic shared characteristics similar to its following main wave. Central-point locations were similar and Spearman's rank coefficients showed high degrees of correlation. Autocorrelation results were similar, with one exception reflecting an appalling anomalous cholera outbreak at an institution for children. Because of the demonstrated similarity of each epidemic's herald and main waves, this study did not detect a spatial characteristic that could explain the observed difference in severity between the studied heralds and mains.
Emerg Infect Dis. 2021 Nov;27(11):2932-2936. doi: 10.3201/eid2711.203372.
This study describes the apparent discontinuation of cholera transmission in Haiti since February 2019. Because vulnerabilities persist and vaccination remains limited, our findings suggest that case-area targeted interventions conducted by rapid response teams played a key role. We question the presence of environmental reservoirs in Haiti and discuss progress toward elimination.
Emerg Infect Dis. 2021 Nov;27(11):2927-2931. doi: 10.3201/eid2711.211144.
We describe the molecular epidemiology of cholera in South Africa during 2018-2020. Vibrio cholerae O1 sequence type (ST) 75 recently emerged and became more prevalent than the V. cholerae O1 biotype El Tor pandemic clone. ST75 isolates were found across large spatial and temporal distances, suggesting local ST75 spread.