Molecular evolution in court: analysis of a large hepatitis C virus outbreak from an evolving source

Abstract

BackgroundMolecular phylogenetic analyses are used increasingly in the epidemiological investigation of outbreaks and transmission cases involving rapidly evolving RNA viruses. Here, we present the results of such an analysis that contributed to the conviction of an anesthetist as being responsible for the infection of 275 of his patients with hepatitis C virus.ResultsWe obtained sequences of the NS5B and E1-E2 regions in the viral genome for 322 patients suspected to have been infected by the doctor, and for 44 local, unrelated controls. The analysis of 4,184 cloned sequences of the E1-E2 region allowed us to exclude 47 patients from the outbreak. A subset of patients had known dates of infection. We used these data to calibrate a relaxed molecular clock and to determine a rough estimate of the time of infection for each patient. A similar analysis led to an estimate for the time of infection of the source. The date turned out to be 10 years before the detection of the outbreak. The number of patients infected was small at first, but it increased substantially in the months before the detection of the outbreak.ConclusionsWe have developed a procedure to integrate molecular phylogenetic reconstructions of rapidly evolving viral populations into a forensic setting adequate for molecular epidemiological analysis of outbreaks and transmission events. We applied this procedure to a large outbreak of hepatitis C virus caused by a single source and the results obtained played a key role in the trial that led to the conviction of the suspected source.

Expansion of Microbial Forensics

“…A full-scale analysis that demonstrated the potential of such investigations was reported by Gonzáles-Candelas et al (28). These authors described in detail a case of a Spanish anesthetist convicted of malpractice by infecting more than 270 of his patients with hepatitis C virus (HCV).…”

“…Tracking sexually transmitted diseases in child molestation, rape cases, and questioned malpractice cases in health care provider outbreaks have been well documented for HIV and HCV cases (21)(22)(23)(24)(25)(26)(27)(28) and have been part of the microbial forensics arena.…”

“…Other examples of microbial forensics investigations included tracing transmission of human immunodeficiency virus (HIV) and hepatitis C virus (HCV) in criminal health-related matters (21)(22)(23)(24)(25)(26)(27)(28), which fall under the biocrime category (Table 1). Therefore, microbial forensics focused on investigations where the microbe or its products (e.g., toxins) were used as weapons or biothreats.…”

The Harvest suite for rapid core-genome alignment and visualization of thousands of intraspecific microbial genomes

“…Multiple genome alignment is a fundamental tool in genomics essential for tracking genome evolution [6][7][8] [26,40], recombination, homoplasy, gene conversion, mobile genetic elements, pseudogenization, and convoluted orthology relationships [25]. In addition, the computational burden of multiple sequence alignment remains very high [41] despite recent progress [42].…”

“…Multiple genome alignment is a fundamental tool in genomics essential for tracking genome evolution [6][7][8], accurate inference of recombination [9][10][11][12][13][14], identification of genomic islands [15,16], analysis of mobile genetic elements [17,18], comprehensive classification of homology [19,20], ancestral genome reconstruction [21], and phylogenomic analyses [22][23][24]. The task of whole-genome alignment is to create a catalog of relationships between the sequences of each genome (ortholog, paralog, xenolog, and so on [25]) to reveal their evolutionary history [26,27].…”