PubMed · 12097718
Anthrax being sent through the postal service brought the risks of bioterrorism home to us all: but what dies it really mean?
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Noel Snell. 2002. Bioterrorism today.. https://pubmed.ncbi.nlm.nih.gov/12097718/
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BACKGROUND: Anthrax remains an important zoonotic disease in Kazakhstan due to the persistence of environmental reservoirs and long-standing endemic foci. Despite ongoing surveillance, the epidemiological characteristics and genetic diversity of circulating Bacillus anthracis strains in the country remain incompletely understood. METHODS: A retrospective epidemiological and phylogenetic investigation of anthrax outbreaks reported in Kazakhstan during 2024 was conducted. Epidemiological data were collected for all laboratory-confirmed human cases and associated outbreak foci. Confirmation of infection was performed by PCR, and B. anthracis isolates were obtained from clinical, environmental and animal-associated samples. Whole-genome sequencing and core-genome single nucleotide polymorphism (cgSNP) analysis were used to characterize the genetic relationships among isolates and to determine their phylogenetic placement. RESULTS: Nine anthrax outbreaks were identified across four regions of Kazakhstan (Almaty, Zhambyl, Atyrau, and West Kazakhstan), resulting in 20 confirmed human cases. All patients were male, with the highest proportion occurring among individuals aged 36-55 years (45%). The mean patient age was 43.9 years (range: 16-64 years). Most infections were associated with slaughtering infected livestock (65%), followed by handling contaminated meat (15%). PCR confirmed infection in all 20 human cases. Culture yielded 17 human-derived B. anthracis isolates from 14 patients and 17 environmental/animal-derived isolates, resulting in 34 isolates in total. Of these, 22 representative isolates underwent whole-genome sequencing. Phylogenetic analysis revealed the circulation of two major lineages. Isolates from Atyrau and West Kazakhstan clustered within the Trans-Eurasian (TEA/STI) lineage. Atyrau isolates formed a tight cluster differing by only 21-32 cgSNPs, consistent with a shared epidemiolocal source, whereas the West Kazakhstan isolate was highly divergent. Zhambyl and Almaty region belonged to the A.Br.Ames lineage but diverged into two distinct sublineages. Zhambyl region isolates demonstrated minimal divergence from the global reference genome Ames Ancestor, differing by only 16-31 SNPs. Almaty region isolates formed an endemic subclone, separated from the reference group by approximately 114 SNPs. Comparison with the Ames Ancestor and Sterne reference strains demonstrated substantial genetic divergence. CONCLUSION: Anthrax outbreaks in Kazakhstan during 2024 were primarily associated with livestock exposure and occurred within established endemic regions. Whole-genome sequencing revealed the coexistence of distinct TEA and Ames lineages, including evidence of persistent local transmission and long-term evolutionary stability of endemic B. anthracis populations. These findings enhance understanding of anthrax epidemiology in Central Asia and support the integration of genomic surveillance into national outbreak investigation programs.
INTRODUCTION: The incidence of anthrax in China has declined since 1990 but has resurged in recent years. The purpose of this study was to describe the epidemiology of anthrax and Bacillus anthracis (B. anthracis) in China from 2020 to 2024 to inform control strategies. METHODS: A descriptive analysis was performed of case characteristics. B. anthracis strains underwent whole-genome sequencing, and phylogenetic relationships were determined by core-genome single nucleotide polymorphism (cgSNP) and canonical single nucleotide polymorphism (canSNP) analysis. RESULTS: Between 2020 and 2024, 1,870 anthrax cases were reported, with a 0.59% case fatality rate. The majority of cases were cutaneous and the incidence increased from year to year. Cases were distributed across 12 provincial-level administrative divisions (PLADs), with most regions showing an increased incidence between 2021 and 2024. Farmers and herders were the most affected occupational groups, and farmers accounted for an increasing proportion of cases. Cases were primarily concentrated among young and middle-aged men and peaked between July and September. A total of 185 B. anthracis strains were identified in the 12 PLADs and were classified into four sublineages (A.Br.001/002, A.Br.Ames, A.Br.Vollum, and A.Br.005/006). A.Br.001/002 was the most prevalent and widely distributed sublineage. Phylogenetic analysis revealed 14 branches, demonstrating population diversity. Cross-clustering was present among strains from different PLADs. CONCLUSIONS: From 2020 to 2024, anthrax cases generally followed historical patterns but the incidence increased, with broader geographical spread, more diverse clinical types, and interprovincial transmission. These findings highlight the need to strengthen anthrax control efforts, particularly in the central and eastern PLADs.
A panel of 10 physicians used the nominal group technique to assess the ability of the Centers for Disease Control and Prevention (CDC) interim guidelines for clinical evaluation of persons with possible inhalational anthrax (IA) to retrospectively identify the 11 patients with IA seen during the October 2001 bioterrorism outbreak. The guidelines would not have identified 10 of 11 of these patients, primarily because the guidelines were designed to address only those patients with a known history of exposure or clearly identified environmental or occupational risk. The panel suggested revisions to the guidelines, primarily consisting of broadening the criteria for evaluation to include either known exposure or environmental occupational risk, or to include clinical symptoms consistent with IA. These extensions of the guidelines retrospectively identified 8 of 11 of the patients with IA from October 2001.