Potential distributions of Bacillus anthracis and Bacillus cereus biovar anthracis causing anthrax in Africa

Abstract

Background Bacillus cereus biovar anthracis (Bcbva) is an emergent bacterium closely related to Bacillus anthracis, the etiological agent of anthrax. The latter has a worldwide distribution and usually causes infectious disease in mammals associated with savanna ecosystems. Bcbva was identified in humid tropical forests of Cô te d'Ivoire in 2001. Here, we characterize the potential geographic distributions of Bcbva in West Africa and B. anthracis in sub-Saharan Africa using an ecological niche modeling approach. Methodology/Principal findings Georeferenced occurrence data for B. anthracis and Bcbva were obtained from public data repositories and the scientific literature. Combinations of temperature, humidity, vegetation greenness, and soils values served as environmental variables in model calibrations. To predict the potential distribution of suitable environments for each pathogen across the study region, parameter values derived from the median of 10 replicates of the best-performing model for each pathogen were used. We found suitable environments predicted for B. anthracis across areas of confirmed and suspected anthrax activity in sub-Saharan Africa, including an east-west corridor from Ethiopia to Sierra Leone in the Sahel region and multiple areas in eastern, central, and southern Africa. The study area for Bcbva was restricted to West and Central Africa to reflect areas that have likely been accessible to Bcbva by dispersal. Model predicted values indicated potential suitable environments within humid forested environments. Background similarity tests in geographic space indicated statistical support to reject the null hypothesis of similarity when comparing environments associated PLOS NEGLECTED TROPICAL DISEASES

TaqMan Assays for Simultaneous Detection of Bacillus anthracis and Bacillus cereus biovar anthracis

“…The TaqMan assays described in this work provide a rapid diagnostic tool for simultaneous detection of B. anthracis and Bcbva. Bcbva is an emerging pathogen that circulates in western and central Africa and a collective review of recent studies of both suggest overlap across much of the region [ 10 , 12 , 17 , 18 , 19 , 20 , 35 ]. Anthrax remains and important and underreported disease in this region and many of the classical microbiology techniques for differentiating B. anthracis from B. cereus do not work to differentiate Bcbva.…”

“…Currently, no single assay exists for the rapid and simultaneous identification of these two pathogens that share an overlapping geographic distribution in western and central Africa [ 16 , 17 , 18 , 19 , 20 ]. Prompt and concurrent diagnosis is necessary in areas where both B. anthracis and Bcbva circulate and could further aid in monitoring the spread of Bcbva across its currently known geographical range.…”

Keeping up with the Bacillus cereus group: taxonomy through the genomics era and beyond

“…For example, prior to 2020, anthrax toxin-producing members of B. cereus s.l. that lack the phenotypic traits characteristic of B. anthracis (Tallent et al 2019) had been referred to in the literature as (i) "B. anthracis" (Leendertz et al 2004), (ii) "B. cereus" (Ehling-Schulz, Lereclus, and Koehler 2019; Hoffmaster et al 2006;Hoffmaster et al 2004;Kamal et al 2017;Marston et al 2016;Pena-Gonzalez et al 2017;Scarff et al 2018), (iii) "B. cereus variety anthracis" (Klee et al 2010), (iv) "B. cereus biovar anthracis" or "B. cereus biovar anthracis" (Antonation et al 2016;Ehling-Schulz, Lereclus, and Koehler 2019;Romero-Alvarez et al 2020;Scarff et al 2018), and could hypothetically be referred to as (v) "B. tropicus" (Carroll, Wiedmann, and Kovac 2020; Parks et al 2020), although, to our knowledge, no one has yet applied this taxonomic label to describe an anthrax-causing B. cereus s.l. strain.…”

The Bacillus cereus Food Infection as Multifactorial Process

“…The fate of the affected target cells has also been described as pore formation in the membranes (measured via influx of propidium iodide into the cells) [378,388], cell survival or death (measured via LDH or alkaline phosphatase release and bioassays targeting the respiratory chain) [359,374,409,416], or programmed cell death via apoptotic or inflammatory pathways [408,412,417]. Aside from the enterotoxins, there have been several reports describing B. cereus biovar anthracis, a variant harboring the Bacillus anthracis-typical plasmid pXO1, which includes genes encoding anthrax-like toxins [418][419][420][421][422][423][424][425][426][427]. This might represent a further, future food poisoning threat.…”