Recent Cholera Publications on PubMed

<em>Vibrio cholerae</em> O37: one of the exceptions that prove the rule

April 12, 2023

Microb Genom. 2023 Apr;9(4). doi: 10.1099/mgen.0.000980.


Between 1965 and 1968, outbreaks of cholera in Sudan and former Czechoslovakia provoked considerable public health concern. These still represent important historical events that need to be linked to the growing genomic evidence describing the aetiological agent of cholera, Vibrio cholerae. Whilst O1 serogroup V. cholerae are canonically associated with epidemic and pandemic cholera, these events were caused by a clone of toxigenic V. cholerae O37 that may be more globally distributed than just to Europe and North Africa. Understanding the biology of these non-O1 strains of V. cholerae is key to understanding how diseases like cholera continue to be globally important. In this article, we consolidate epidemiological, molecular and genomic descriptions of the bacteria responsible for these outbreaks. We attempt to resolve discrepancies in order to summarize the history and provenance of as many commonly used serogroup O37 strains as possible. Finally, we highlight the potential for whole-genome sequencing of V. cholerae O37 isolates from strain collections to shed light on the open questions that we identify.

PMID:37043377 | DOI:10.1099/mgen.0.000980

Development of a Scorecard to Monitor Progress toward National Cholera Elimination: Its Application in Uganda

April 10, 2023

Am J Trop Med Hyg. 2023 Apr 10:tpmd230007. doi: 10.4269/ajtmh.23-0007. Online ahead of print.


In 2017, the Global Task Force for Cholera Control (GTFCC) set a goal to eliminate cholera from ≥ 20 countries and to reduce cholera deaths by 90% by 2030. Many countries have included oral cholera vaccine (OCV) in their cholera control plans. We felt that a simple, user-friendly monitoring tool would be useful to guide national progress toward cholera elimination. We reviewed cholera surveillance data of Uganda from 2015 to 2021 by date and district. We defined a district as having eliminated cholera if cholera was not reported in that district for at least 4 years. We prepared maps to show districts with cholera, districts that had eliminated it, and districts that had eliminated it but then "relapsed." These maps were compared with districts where OCV was used and the hotspot map recommended by the GTFCC. Between 2018 and 2021, OCV was administered in 16 districts previously identified as hotspots. In 2018, cholera was reported during at least one of the four previous years from 36 of the 146 districts of Uganda. This number decreased to 18 districts by 2021. Cholera was deemed "eliminated" from four of these 18 districts but then "relapsed." The cholera elimination scorecard effectively demonstrated national progress toward cholera elimination and identified districts where additional resources are needed to achieve elimination by 2030. Identification of the districts that have eliminated cholera and those that have relapsed will assist the national programs to focus on addressing the factors that result in elimination or relapse of cholera.

PMID:37037429 | DOI:10.4269/ajtmh.23-0007

Post-flood outbreaks of Cholera in Pakistan; Endemic-to-epidemic

April 6, 2023

J Infect Dev Ctries. 2023 Mar 31;17(3):423-424. doi: 10.3855/jidc.17512.


PMID:37023423 | DOI:10.3855/jidc.17512

WHO Warns "Very High" Global Risk as Cholera Cases Spread

April 5, 2023

JAMA. 2023 Apr 25;329(16):1340. doi: 10.1001/jama.2023.5618.


PMID:37018004 | DOI:10.1001/jama.2023.5618

Immigration Policy and the Health of Latina Mothers and Their Infants

April 5, 2023

J Immigr Minor Health. 2023 Apr 5. doi: 10.1007/s10903-023-01476-3. Online ahead of print.


Restrictive immigration policies may adversely affect the health of Latina mothers and their infants. We hypothesized that undocumented Latina mothers and their US born children would have worse birth outcomes and healthcare utilization following the November 2016 election. We used a controlled interrupted time series to estimate the impact of the 2016 presidential election on low birth weight (LBW), preterm birth, maternal depression, well child visit attendance, cancelled visits, and emergency department (ED) visits among infants born to Latina mothers on emergency Medicaid, a proxy for undocumented immigration status. There was a 5.8% (95% CI: -0.99%, 12.5%) increase in LBW and 4.6% (95% CI: -1.8%, 10.9%) increase in preterm births immediately after the 2016 election compared to controls. While these findings were not statistically significant at p < 0.05, the majority of our data suggest worsened birth outcomes among undocumented Latina mothers after the election, consistent with larger prior studies. There was no difference in well child or ED visits. While restrictive policies may have contributed to worse birth outcomes among undocumented Latina mothers, our findings suggest that Latino families still attend infants' scheduled visits.

PMID:37020058 | DOI:10.1007/s10903-023-01476-3

Food as a Driver of a Cholera Epidemic in Jijiga, Ethiopia-June 2017

April 3, 2023

Am J Trop Med Hyg. 2023 Apr 3;108(5):963-967. doi: 10.4269/ajtmh.22-0734. Print 2023 May 3.


We conducted a case-control study to identify risk and protective factors during a cholera outbreak in Jijiga, Ethiopia, in June 2017. A case-patient was defined as anyone > 5 years old with at least three loose stools in 24 hours who was admitted to a cholera treatment center in Jijiga on or after June 16, 2017. Two controls were matched to each case by type of residency (rural or urban) and age group. We enrolled 55 case-patients and 102 controls from June 16 to June 23, 2017. Identified risk factors for cholera were male sex, eating cold food, and eating food outside the home. Eating hot food was protective, as was reported handwashing after defecation; no other reported water, sanitation, and hygiene factors were associated with cholera risk. Recommendations included continuing messaging about safe food handling practices at home, the dangers of consuming meals prepared away from home, and the importance of hand hygiene practices.

PMID:37011894 | DOI:10.4269/ajtmh.22-0734

Responding to the global cholera pandemic

April 3, 2023

Bull World Health Organ. 2023 Apr 1;101(4):234-235. doi: 10.2471/BLT.23.020423.


An increase in cholera outbreaks is prompting renewed calls for urgent multisectoral action. Fid Thomson reports.

PMID:37008267 | PMC:PMC10042091 | DOI:10.2471/BLT.23.020423

Firdausi Qadri: the struggle against cholera

April 3, 2023

Bull World Health Organ. 2023 Apr 1;101(4):236-237. doi: 10.2471/BLT.23.030423.


Firdausi Qadri talks to Gary Humphreys about the need for new cholera vaccines and increased vaccine production to meet growing regional and global demand.

PMID:37008264 | PMC:PMC10042083 | DOI:10.2471/BLT.23.030423

Comparison of prevention of parent-to-child HIV transmission programme &amp; national biennial HIV sentinel surveillance data for tracking HIV epidemic in India

April 3, 2023

Indian J Med Res. 2023 Apr 3. doi: 10.4103/ijmr.ijmr_3311_21. Online ahead of print.


BACKGROUND & OBJECTIVES: HIV sentinel surveillance (HSS) among antenatal women in India has been used to track the epidemic for many years. However, reliable tracking at the local level is not possible as ANC sentinel sites are limited in number and cover a smaller sample size at each site. Prevention of parent-to-child-transmission (PPTCT) programme data has a potential advantage due to better geographical coverage, which could provide more precise HIV case estimates; therefore, we compared HSS ANC data with PPTCT programme data for HIV tracking.

METHODS: Out of the 499 surveillance sites, where HSS and PPTCT programme was being conducted in 2015, 210 sites (140 urban and 70 rural) were selected using a stratified random sampling method. HSS (n=72,981) and PPTCT (n=112,832) data records were linked confidentially. The socio-demographic characteristics of HSS and PPTCT attendees were compared. HIV prevalence from HSS ANC was compared with the PPTCT programme data using Chi-square test. State- and site-level correlation of HIV prevalence was also done. Concordance between HSS and PPTCT HIV positivity was estimated using kappa statistics.

RESULTS: The age distribution of HSS and PPTCT attendees was similar (range: 23 to 27 yr); however, HSS ANC participants were better educated, whereas PPTCT recorded a higher proportion of homemakers. The correlation of HIV prevalence between HSS and PPTCT was high (r=0.9) at the State level and moderate at the site level (r=0.7). The HIV positivity agreement between HSS ANC and PPTCT was good (kappa=0.633). A similar prevalence was reported across 26 States, whereas PPTCT had a significantly lower prevalence than HSS in three States where PPTCT coverage was low. Overall HIV prevalence was 0.31 per cent in HSS and 0.22 per cent in PPTCT (P<0.001).

INTERPRETATION & CONCLUSIONS: High-quality PPTCT programme data can provide reliable HIV trends in India. An operational framework for PPTCT-based surveillance should be pilot-tested in a phased manner before replacing HSS with PPTCT.

PMID:37006025 | DOI:10.4103/ijmr.ijmr_3311_21

Politicization of water, humanitarian response, and health in Syria as a contributor to the ongoing cholera outbreak

March 29, 2023

Int J Infect Dis. 2023 Jun;131:115-118. doi: 10.1016/j.ijid.2023.03.042. Epub 2023 Mar 27.


In September 2022, the Syrian Ministry of Health declared a cholera outbreak after a surge of acute watery diarrhea cases. Since then, cases have been reported across Syria, particularly in the northwest. This ongoing outbreak reflects a pattern of politicizing water, humanitarian response, and health throughout the country's protracted conflict. Interference with water, sanitation, and hygiene (WASH) infrastructure has been a key component of this politicization, impeding detection, prevention, case management, and control. Droughts and floods have exacerbated the WASH situation, as have the early 2023 Türkiye-Syria earthquakes. The humanitarian response after the earthquakes has also faced politicization, leading to increased risk of surges in cases of cholera and other waterborne diseases. This has all occurred in a conflict where health care has been weaponized, attacks on health care and related infrastructure are the norm, and syndromic surveillance and outbreak response have been influenced and restricted by politics. Cholera outbreaks are entirely preventable; what we see in Syria is cholera reflecting the myriad ways in which the right to health has been brought under fire in the Syrian conflict. The recent earthquakes are additional assaults, which raise urgent concerns that a surge of cholera cases, particularly in northwest Syria, may now become uncontrolled.

PMID:36990201 | DOI:10.1016/j.ijid.2023.03.042

Cholera makes a comeback amid calls to boost vaccine production

March 29, 2023

BMJ. 2023 Mar 29;380:p636. doi: 10.1136/bmj.p636.


PMID:36990501 | DOI:10.1136/bmj.p636

Global Patterns of Trends in Cholera Mortality

March 28, 2023

Trop Med Infect Dis. 2023 Mar 13;8(3):169. doi: 10.3390/tropicalmed8030169.


BACKGROUND: Cholera is a large public health issue, especially in countries with limited resources. The aim of the study was to determine trends in global cholera mortality from 1990-2019.

METHODS: This research is an observational, descriptive epidemiological study. The age-standardized rates (ASRs, per 100,000 population) of cholera mortality from 1990 to 2019 were evaluated through joinpoint regression analysis (by calculating Odds Ratio-OR, with corresponding 95% Confidence Interval-95% CI).

RESULTS: From 1990-2019 in the world, the number of deaths due to cholera in both sexes together increased, ranging from 83,045 in 1990 to 117,167 in 2019. During the observed period, there were about 3.0 million deaths due to cholera in the world. In both sexes together in 2019, the cholera mortality rate was the highest in Nigeria (ARS = 39.19) and Central African Republic (ARS = 38.80), followed by populations in Eritrea (ARS = 17.62) and Botswana (ARS = 13.77). Globally, cholera-related mortality significantly decreased in males (AAPC = -0.4%, 95% CI = -0.7 to -0.1), while a stable trend was noted in females (AAPC = -0.1%, 95% CI = -0.4 to 0.2) in the observed period. In the African Region, significantly increasing cholera-related mortality trends were observed both in males and females (AAPC = 1.3% and AAPC = 1.1%, respectively).

CONCLUSIONS: Cholera mortality showed a constantly increasing trend in the African Region over the last three decades. More efforts in cholera management are necessary for effective response to the growing mortality in developing countries.

PMID:36977170 | DOI:10.3390/tropicalmed8030169

Cholera outbreak in Africa

March 25, 2023

Lancet Infect Dis. 2023 Apr;23(4):411. doi: 10.1016/S1473-3099(23)00149-4.


PMID:36965496 | DOI:10.1016/S1473-3099(23)00149-4

The impact of social and environmental extremes on cholera time varying reproduction number in Nigeria

March 24, 2023

PLOS Glob Public Health. 2022 Dec 14;2(12):e0000869. doi: 10.1371/journal.pgph.0000869. eCollection 2022.


Nigeria currently reports the second highest number of cholera cases in Africa, with numerous socioeconomic and environmental risk factors. Less investigated are the role of extreme events, despite recent work showing their potential importance. To address this gap, we used a machine learning approach to understand the risks and thresholds for cholera outbreaks and extreme events, taking into consideration pre-existing vulnerabilities. We estimated time varying reproductive number (R) from cholera incidence in Nigeria and used a machine learning approach to evaluate its association with extreme events (conflict, flood, drought) and pre-existing vulnerabilities (poverty, sanitation, healthcare). We then created a traffic-light system for cholera outbreak risk, using three hypothetical traffic-light scenarios (Red, Amber and Green) and used this to predict R. The system highlighted potential extreme events and socioeconomic thresholds for outbreaks to occur. We found that reducing poverty and increasing access to sanitation lessened vulnerability to increased cholera risk caused by extreme events (monthly conflicts and the Palmers Drought Severity Index). The main limitation is the underreporting of cholera globally and the potential number of cholera cases missed in the data used here. Increasing access to sanitation and decreasing poverty reduced the impact of extreme events in terms of cholera outbreak risk. The results here therefore add further evidence of the need for sustainable development for disaster prevention and mitigation and to improve health and quality of life.

PMID:36962831 | DOI:10.1371/journal.pgph.0000869

Cholera epidemic amidst the COVID-19 pandemic in Moroto district, Uganda: Hurdles and opportunities for control

March 24, 2023

PLOS Glob Public Health. 2022 Oct 12;2(10):e0000590. doi: 10.1371/journal.pgph.0000590. eCollection 2022.


INTRODUCTION: On 21st March 2020, the first COVID-19 case was detected in Uganda and a COVID-19 pandemic declared. On the same date, a nationwide lockdown was instituted in response to the pandemic. Subsequently, more cases were detected amongst the returning international travelers as the disease continued to spread across the country. On May 14th, 2020, a cholera epidemic was confirmed in Moroto district at a time when the district had registered several COVID-19 cases and was in lockdown. This study aimed to describe the cholera epidemic and response activities during the COVID-19 pandemic as well as the hurdles and opportunities for cholera control encountered during the response.

MATERIALS AND METHODS: In a cross-sectional study design, we reviewed Moroto district's weekly epidemiological records on cholera and COVID-19 from April to July 2020. We obtained additional information through a review of the outbreak investigation and control reports. Data were analyzed and presented in frequencies, proportions, attack rates, case fatality rates, graphs, and maps.

RESULTS: As of June 28th, 2020, 458 cases presenting with severe diarrhea and/or vomiting were line listed in Moroto district. The most affected age group was 15-30 years, 30.1% (138/458). The females, 59.0% [270/458], were the majority. The Case Fatality Rate (CFR) was 0.4% (2/458). Whereas home use of contaminated water following the vandalization of the only clean water source in Natapar Kocuc village, Moroto district, could have elicited the epidemic, implementing COVID-19 preventive and control measures presented some hurdles and opportunities for cholera control. The significant hurdles were observing the COVID-19 control measures such as social distancing, wearing of masks, and limited time in the community due to the need to observe curfew rules starting at 6.00 pm. The opportunities from COVID-19 measures complementary to cholera control measures included frequent hand washing, travel restrictions within the district & surrounding areas, and closure of markets.

CONCLUSION: COVID-19 preventive and control measures such as social distancing, wearing of masks, and curfew rules may be a hurdle to cholera control whereas frequent hand washing, travel restrictions within the district & surrounding areas, and closure of markets may present opportunities for cholera control. Other settings experiencing concurrent cholera and COVID-19 outbreaks can borrow lessons from this study.

PMID:36962556 | DOI:10.1371/journal.pgph.0000590

Multicountry cholera outbreak alert in Kenya: Current efforts and recommendations

March 17, 2023

Int J Surg. 2023 Mar 1;109(3):555-557. doi: 10.1097/JS9.0000000000000130.


PMID:36928043 | DOI:10.1097/JS9.0000000000000130

Mapping of cholera hotspots in Kenya using epidemiologic and water, sanitation, and hygiene (WASH) indicators as part of Kenya's new 2022-2030 cholera elimination plan

March 17, 2023

PLoS Negl Trop Dis. 2023 Mar 17;17(3):e0011166. doi: 10.1371/journal.pntd.0011166. eCollection 2023 Mar.


Cholera is an issue of major public health importance. It was first reported in Kenya in 1971, with the country experiencing outbreaks through the years, most recently in 2021. Factors associated with the outbreaks in Kenya include open defecation, population growth with inadequate expansion of safe drinking water and sanitation infrastructure, population movement from neighboring countries, crowded settings such as refugee camps coupled with massive displacement of persons, mass gathering events, and changes in rainfall patterns. The Ministry of Health, together with other ministries and partners, revised the national cholera control plan to a multisectoral cholera elimination plan that is aligned with the Global Roadmap for Ending Cholera. One of the key features in the revised plan is the identification of hotspots. The hotspot identification exercise followed guidance and tools provided by the Global Task Force on Cholera Control (GTFCC). Two epidemiological indicators were used to identify the sub-counties with the highest cholera burden: incidence per population and persistence. Additionally, two indicators were used to identify sub-counties with poor WASH coverage due to low proportions of households accessing improved water sources and improved sanitation facilities. The country reported over 25,000 cholera cases between 2015 and 2019. Of 290 sub-counties, 25 (8.6%) sub-counties were identified as a high epidemiological priority; 78 (26.9%) sub-counties were identified as high WASH priority; and 30 (10.3%) sub-counties were considered high priority based on a combination of epidemiological and WASH indicators. About 10% of the Kenyan population (4.89 million) is living in these 30-combination high-priority sub-counties. The novel method used to identify cholera hotspots in Kenya provides useful information to better target interventions in smaller geographical areas given resource constraints. Kenya plans to deploy oral cholera vaccines in addition to WASH interventions to the populations living in cholera hotspots as it targets cholera elimination by 2030.

PMID:36930650 | DOI:10.1371/journal.pntd.0011166

A Molecular and Epidemiological Study of Cholera Outbreak in Sulaymaniyah Province, Iraq, in 2022

March 17, 2023

Pol J Microbiol. 2023 Mar 24;72(1):39-46. doi: 10.33073/pjm-2023-008. Print 2023 Mar 1.


Cholera is a disease caused by a Gram-negative bacterium Vibrio cholerae and is among the significant threats to global public health. The disease is mainly spread in the hot months of the year; low sanitation and lack of clean water are the major causes of the disease. In this study, we conducted a molecular and epidemiological study of the recent outbreak in the city of Sulaymaniyah in Iraq. Based on the bacteriological, serological, and molecular identification of the bacterium, it was shown that V. cholerae O1 serotype Ogawa caused the disease. Additionally, the number of positive cholera cases were higher in June compared to July (391 positive cases in June and 23 in July). Moreover, the majority (> 60%) of the cholera cases were recorded among 20-44-year-old people in both months; however, there was no significant difference in the patient genders diagnosed every month. Overall, this is the first report on the recent cholera outbreak in the city of Sulaimaniyah in Iraq.

PMID:36929893 | DOI:10.33073/pjm-2023-008

A retrospective analysis of serological &amp; molecular testing data on dengue fever in Kolkata &amp; adjacent districts during 2016-2019

March 17, 2023

Indian J Med Res. 2022 Oct-Nov;156(4&5):608-614. doi: 10.4103/ijmr.IJMR_2612_19.


BACKGROUND & OBJECTIVES: Regional Virus Research and Diagnostic Laboratory established at ICMR-National Institute of Cholera and Enteric Diseases (NICED) regularly receives samples for dengue screening and serotyping from patients of acute febrile illness (AFI) from Kolkata and adjacent districts. In this study, data over a three year period (August 2016-July 2019) was retrospectively analyzed to provide insight into the epidemiological trends of dengue fever in this region.

METHODS: Serological screening of dengue was performed by detection of NS1 antigen and/or immunoglobulin M (IgM) antibody. Dengue serotyping was done by conventional or real-time reverse transcriptase-PCR. The data were analyzed to describe the distribution of dengue with respect to age of patient, duration of fever on the day of blood collection and month of the year. Zip codes were used for spatial plotting.

RESULTS: Out of the 24,474 samples received from Kolkata and its adjacent districts (Hooghly, Howrah, North and South 24 Parganas), 38.3 per cent (95% confidence interval: 37.7-38.9%) samples were screened positive for dengue. The correlation between age and dengue positivity was found to be weak. A combination of dengue NS1 antigen and dengue IgM antibody detection may be a better option for detecting dengue positivity compared to a single test. Most AFI cases were tested from August to November during the study period, with maximum dengue positivity noted during September (45.9%). The predominant serotype of 2016, dengue virus serotype 1 (DENV-1), was almost entirely replaced by DENV-2 in 2017 and 2018.

INTERPRETATION & CONCLUSIONS: Dengue continues to be an important cause of AFI in the region and round-the-year preventive measures are required for its control. Serotype switching is alarming and should be monitored routinely.

PMID:36926776 | DOI:10.4103/ijmr.IJMR_2612_19

Spectrum of ctxB genotypes, antibiogram profiles and virulence genes of Vibrio cholerae serogroups isolated from environmental water sources from Odisha, India

March 17, 2023

BMC Microbiol. 2023 Mar 16;23(1):75. doi: 10.1186/s12866-023-02811-2.


BACKGROUND: The present study reports on the comprehensive analysis of Vibrio cholerae O1 and non-O1/non-O139 serogroups isolated from environmental water sources during cholera outbreaks, epidemics and surveillance studies between years 2007 to 2019 from different districts of Odisha, India.

METHODS: A total of 85 stocked cultures of V. cholerae O1 and non-O1/non-O139 strains were analyzed for different ctxB genotypes, toxic genes, antibiogram profiles through PCR assays and pulsotyped by pulsed-field gel electrophoresis (PFGE).

RESULTS: From all V. cholerae strains tested, 51 isolates were O1 Ogawa and the rest 34 strains were non-O1/non-O139. All the V. cholerae O1 strains were altered El Tor variants carrying ctxB1, ctxB3 and ctxB7 genotypes. However, only ctxB1 genotypes were present in V. cholerae non-O1/non-O139. Though non-O1/non-O139 strains were negative by O1 antisera, 20% strains were positive for rfbO1 gene by PCR assay. All the V. cholerae isolates possessed a variety of virulence genes including ace, ctxAB, toxR, zot, hlyA which were in higher percentage in the case of V. cholerae O1. The Vibrio cholerae O1 and non-O1-/non-O139 strains showed multiple antibiotic resistances in 2007 and 2012. The PCR detection of four resistance associated genes (strB, dfrA1, sulll, SXT) confirmed higher prevalence in V. cholerae non-O1/non-O139 strains. The PFGE analysis revealed 3 pulsotypes having 93% similarity among V. cholerae O1 strains.

CONCLUSION: This study indicates the changing epidemiology, antibiogram patterns and continuous genetic variation in environmental V. cholerae strains of Odisha over the years. So continuous surveillance is necessary to understand the changing patterns of V. cholerae different serogroups isolated from stool and water samples from Odisha.

PMID:36927368 | DOI:10.1186/s12866-023-02811-2