A prolonged cholera outbreak caused by drinking contaminated stream water, Kyangwali refugee settlement, Hoima District, Western Uganda: 2018

Untangling the effects of multiple exposures with a common reference group in an epidemiologic study: A practical revisit

When assessing multiple exposures in epidemiologic studies, epidemiologists often use multivariable regression models with main effects only to control for confounding. This method can mask the true effects of individual exposures, potentially leading to wrong conclusions. We revisited a simple, practical, and often overlooked approach to untangle effects of the exposures of interest, in which the combinations of all levels of the exposures of interest are recoded into a single, multicategory variable. One category, usually the absence of all exposures of interest, is selected as the common reference group (CRG). All other categories representing individual and joint exposures are then compared to the CRG using indicator variables in a regression model or in a 2×2 contingency table analysis. Using real data examples, we showed that using the CRG analysis results in estimates of individual and joint effects that are mutually comparable and free of each other's confounding effects, yielding a clear, accurate, intuitive, and simple summarization of epidemiologic study findings involving multiple exposures of interest.

Estimating the proportion of clinically suspected cholera cases that are true Vibrio cholerae infections: A systematic review and meta-analysis

BACKGROUND

Cholera surveillance relies on clinical diagnosis of acute watery diarrhea. Suspected cholera case definitions have high sensitivity but low specificity, challenging our ability to characterize cholera burden and epidemiology. Our objective was to estimate the proportion of clinically suspected cholera that are true Vibrio cholerae infections and identify factors that explain variation in positivity.

METHODS AND FINDINGS

We conducted a systematic review of studies that tested ≥10 suspected cholera cases for V. cholerae O1/O139 using culture, PCR, and/or a rapid diagnostic test. We searched PubMed, Embase, Scopus, and Google Scholar for studies that sampled at least one suspected case between January 1, 2000 and April 19, 2023, to reflect contemporary patterns in V. cholerae positivity. We estimated diagnostic test sensitivity and specificity using a latent class meta-analysis. We estimated V. cholerae positivity using a random-effects meta-analysis, adjusting for test performance. We included 119 studies from 30 countries. V. cholerae positivity was lower in studies with representative sampling and in studies that set minimum ages in suspected case definitions. After adjusting for test performance, on average, 52% (95% credible interval (CrI): 24%, 80%) of suspected cases represented true V. cholerae infections. After adjusting for test performance and study methodology, the odds of a suspected case having a true infection were 5.71 (odds ratio 95% CrI: 1.53, 15.43) times higher when surveillance was initiated in response to an outbreak than in non-outbreak settings. Variation across studies was high, and a limitation of our approach was that we were unable to explain all the heterogeneity with study-level attributes, including diagnostic test used, setting, and case definitions.

CONCLUSIONS

In this study, we found that burden estimates based on suspected cases alone may overestimate the incidence of medically attended cholera by 2-fold. However, accounting for cases missed by traditional clinical surveillance is key to unbiased cholera burden estimates. Given the substantial variability in positivity between settings, extrapolations from suspected to confirmed cases, which is necessary to estimate cholera incidence rates without exhaustive testing, should be based on local data.

Isolation and Identification of Non-O1/Non-O139 Vibrio cholerae in Wild Birds Inhabiting Wetlands in Metropolitan Lima, Peru

During a survey in wetlands from southern Lima, Peru, two non-O1/non-O139 Vibrio cholerae isolates were obtained from samples collected from an American Oystercatcher (Haematopus palliatus) and a Wren-like Rushbird (Phleocryptes melanops). Vibrio cholerae was identified by amplification and sequencing of 16S rRNA, differentially grown on CHROMagar Vibrio media, and confirmed by ompW amplification. Isolates were confirmed to be non-O1/non-O139 serotypes and to lack the ctxA gene as inferred using PCR. Susceptibility to eight antimicrobial agents was assessed, with one isolate being resistant to azithromycin, doxycycline, tetracycline, and furazolidone. Our results indicate the utility of surveillance for V. cholerae in wetlands in the metropolitan Lima area.

A novel fractional order model of SARS-CoV-2 and Cholera disease with real data

This study presents a novel approach to investigating COVID-19 and Cholera disease. In this situation, a fractional-order model is created to investigate the COVID-19 and Cholera outbreaks in Congo. The existence, uniqueness, positivity, and boundedness of the solution are studied. The equilibrium points and their stability conditions are achieved. Subsequently, the basic reproduction number (the virus transmission coefficient) is calculated that simply refers to the number of people, to whom an infected person can make infected, as R 0 = 6 . 7442389 e - 10 by using the next generation matrix method. Next, the sensitivity analysis of the parameters is performed according to R 0 . To determine the values of the parameters in the model, the least squares curve fitting method is utilized. A total of 22 parameter values in the model are estimated by using real Cholera data from Congo. Finally, to find out the dynamic behavior of the system, numerical simulations are presented. The outcome of the study indicates that the severity of the Cholera epidemic cases will decrease with the decrease in cases of COVID-19, through the implementation and follow-up of safety measures that have been taken to reduce COVID-19 cases.

Establishing a Public Health Emergency Operations Center in an Outbreak-Prone Country: Lessons Learned in Uganda, January 2014 to December 2021

Uganda is highly vulnerable to public health emergencies (PHEs) due to its geographic location next to the Congo Basin epidemic hot spot, placement within multiple epidemic belts, high population growth rates, and refugee influx. In view of this, Uganda's Ministry of Health established the Public Health Emergency Operations Center (PHEOC) in September 2013, as a central coordination unit for all PHEs in the country. Uganda followed the World Health Organization's framework to establish the PHEOC, including establishing a steering committee, acquiring legal authority, developing emergency response plans, and developing a concept of operations. The same framework governs the PHEOC's daily activities. Between January 2014 and December 2021, Uganda's PHEOC coordinated response to 271 PHEs, hosted 207 emergency coordination meetings, trained all core staff in public health emergency management principles, participated in 21 simulation exercises, coordinated Uganda's Global Health Security Agenda activities, established 6 subnational PHEOCs, and strengthened the capacity of 7 countries in public health emergency management. In this article, we discuss the following lessons learned: PHEOCs are key in PHE coordination and thus mitigate the associated adverse impacts; although the functions of a PHEOC may be legalized by the existence of a National Institute of Public Health, their establishment may precede formally securing the legal framework; staff may learn public health emergency management principles on the job; involvement of leaders and health partners is crucial to the success of a public health emergency management program; subnational PHEOCs are resourceful in mounting regional responses to PHEs; and service on the PHE Strategic Committee may be voluntary.