Pathogen genomics study of an early medieval community in Germany reveals extensive co-infections.

BACKGROUND: The pathogen landscape in the Early European Middle Ages remains largely unexplored. Here, we perform a systematic pathogen screening of the rural community Lauchheim "Mittelhofen," in present-day Germany, dated to the Merovingian period, between fifth and eighth century CE. Skeletal remains of individuals were subjected to an ancient DNA metagenomic analysis. Genomes of the detected pathogens were reconstructed and analyzed phylogenetically. RESULTS: Over 30% of the individuals exhibit molecular signs of infection with hepatitis B virus (HBV), parvovirus B19, variola virus (VARV), and Mycobacterium leprae. Seven double and one triple infection were detected. We reconstructed four HBV genomes and one genome each of B19, VARV, and M. leprae. All HBV genomes are of genotype D4 which is rare in Europe today. The VARV strain exhibits a unique pattern of gene loss indicating that viruses with different gene compositions were circulating in the Early Middle Ages. The M. leprae strain clustered in branch 3 together with the oldest to-date genome from the UK. CONCLUSIONS: The high burden of infectious disease, together with osteological markers of physiological stress, reflect a poor health status of the community. This could have been an indirect result of the climate decline in Europe at the time, caused by the Late Antique Little Ice Age (LALIA). Our findings suggest that LALIA may have created an ecological context in which persistent outbreaks set the stage for major epidemics of severe diseases such as leprosy and smallpox hundreds of years later.

Ancient DNA confirmation of lepromatous leprosy in a skeleton with concurrent osteosarcoma, excavated from the leprosarium of St. Mary Magdalen in Winchester, Hants., UK.

To establish a biological profile and disease aetiologies for one of four burials recovered during a Time Team dig at the St. Mary Magdalen leprosarium, Winchester, UK in AD 2000. Osteological techniques were applied to estimate age at death, biological sex, stature and pathology. Visual assessment of the material was supplemented by radiographic examination. Evidence for leprosy DNA was sought using ancient DNA (aDNA) analysis. The remains are those of a male individual excavated from a west-east aligned grave. The skeleton shows signs of two pathologies. Remodelling of the rhino-maxillary area and degenerative changes to small bones of the feet and reactive bone on the distal lower limbs suggest a multibacillary form of leprosy, whereas the right tibia and fibula show the presence of a primary neoplasm identified as an osteosarcoma. The aDNA study confirmed presence of Mycobacterium leprae in several skeletal elements, and the strain was genotyped to the 3I lineage, one of two main SNP types present in mediaeval Britain and ancestral to extant strains in America. This is a rare documentation of leprosy in association with a primary neoplasm.

Genomics of Ancient Pathogens: First Advances and Prospects.

Paleogenomics is one of the urgent and promising areas of interdisciplinary research in the today's world science. New genomic methods of ancient DNA (aDNA) analysis, such as next generation sequencing (NGS) technologies, make it possible not only to obtain detailed genetic information about historical and prehistoric human populations, but also to study individual microbial and viral pathogens and microbiomes from different ancient and historical objects. Studies of aDNA of pathogens by reconstructing their genomes have so far yielded complete sequences of the ancient pathogens that played significant role in the history of the world: Yersinia pestis (plague), Variola virus (smallpox), Vibrio cholerae (cholera), HBV (hepatitis B virus), as well as the equally important endemic human infectious agents: Mycobacterium tuberculosis (tuberculosis), Mycobacterium leprae (leprosy), and Treponema pallidum (syphilis). Genomic data from these pathogens complemented the information previously obtained by paleopathologists and allowed not only to identify pathogens from the past pandemics, but also to recognize the pathogen lineages that are now extinct, to refine chronology of the pathogen appearance in human populations, and to reconstruct evolutionary history of the pathogens that are still relevant to public health today. In this review, we describe state-of-the-art genomic research of the origins and evolution of many ancient pathogens and viruses and examine mechanisms of the emergence and spread of the ancient infections in the mankind history.

Ancient genomes reveal structural shifts after the arrival of Steppe-related ancestry in the Italian Peninsula.

Across Europe, the genetics of the Chalcolithic/Bronze Age transition is increasingly characterized in terms of an influx of Steppe-related ancestry. The effect of this major shift on the genetic structure of populations in the Italian Peninsula remains underexplored. Here, genome-wide shotgun data for 22 individuals from commingled cave and single burials in Northeastern and Central Italy dated between 3200 and 1500 BCE provide the first genomic characterization of Bronze Age individuals (n = 8; 0.001-1.2× coverage) from the central Italian Peninsula, filling a gap in the literature between 1950 and 1500 BCE. Our study confirms a diversity of ancestry components during the Chalcolithic and the arrival of Steppe-related ancestry in the central Italian Peninsula as early as 1600 BCE, with this ancestry component increasing through time. We detect close patrilineal kinship in the burial patterns of Chalcolithic commingled cave burials and a shift away from this in the Bronze Age (2200-900 BCE) along with lowered runs of homozygosity, which may reflect larger changes in population structure. Finally, we find no evidence that the arrival of Steppe-related ancestry in Central Italy directly led to changes in frequency of 115 phenotypes present in the dataset, rather that the post-Roman Imperial period had a stronger influence, particularly on the frequency of variants associated with protection against Hansen's disease (leprosy). Our study provides a closer look at local dynamics of demography and phenotypic shifts as they occurred as part of a broader phenomenon of widespread admixture during the Chalcolithic/Bronze Age transition.

Insights from ancient DNA analysis of Egyptian human mummies: clues to disease and kinship.

The molecular Egyptology field started in the mid-eighties with the first publication on the ancient DNA (aDNA) analysis of an Egyptian mummy. Egypt has been a major interest for historians, archeologists, laymen as well as scientists. The aDNA research on Egyptian biological remains has been fueled by their abundance and relatively well-preserved states through artificial mummification and by the advanced analytical techniques. Early doubts of aDNA integrity within the Egyptian mummies and data authenticity were later abated with studies proving successfully authenticated aDNA retrieval. The current review tries to recapitulate the published studies presenting paleogenomic evidence of disease diagnosis and kinship establishment for the Egyptian human remains. Regarding disease diagnosis, the prevailing literature was on paleogenomic evidence of infectious diseases in the human remains. A series of reports presented evidence for the presence of tuberculosis and/or malaria. In addition, there were solitary reports of the presence of leprosy, diphtheria, bacteremia, toxoplasmosis, schistosomiasis and leishmaniasis. On the contrary, paleogenomic evidence of the presence of rare diseases was quite scarce and mentioned only in two articles. On the other hand, kinship analysis of Egyptian human remains, including that of Tutankhamen, was done using both mitochondrial DNA sequences and nuclear DNA markers, to establish family relationships in four studies. It is clear that the field of molecular Egyptology is still a largely unexplored territory. Nevertheless, the paleogenomic investigation of Egyptian remains could make significant contributions to biomedical sciences (e.g. elucidation of coevolution of human host-microbe interrelationship) as well as to evidence-based archeology.

Comparison of target enrichment strategies for ancient pathogen DNA.

In ancient DNA research, the degraded nature of the samples generally results in poor yields of highly fragmented DNA; targeted DNA enrichment is thus required to maximize research outcomes. The three commonly used methods - array-based hybridization capture and in-solution capture using either RNA or DNA baits - have different characteristics that may influence the capture efficiency, specificity and reproducibility. Here we compare their performance in enriching pathogen DNA of Mycobacterium leprae and Treponema pallidum from 11 ancient and 19 modern samples. We find that in-solution approaches are the most effective method in ancient and modern samples of both pathogens and that RNA baits usually perform better than DNA baits.

The Recovery, Interpretation and Use of Ancient Pathogen Genomes.

The ability to sequence genomes from ancient biological material has provided a rich source of information for evolutionary biology and engaged considerable public interest. Although most studies of ancient genomes have focused on vertebrates, particularly archaic humans, newer technologies allow the capture of microbial pathogens and microbiomes from ancient and historical human and non-human remains. This coming of age has been made possible by techniques that allow the preferential capture and amplification of discrete genomes from a background of predominantly host and environmental DNA. There are now near-complete ancient genome sequences for three pathogens of considerable historical interest - pre-modern bubonic plague (Yersinia pestis), smallpox (Variola virus) and cholera (Vibrio cholerae) - and for three equally important endemic human disease agents - Mycobacterium tuberculosis (tuberculosis), Mycobacterium leprae (leprosy) and Treponema pallidum pallidum (syphilis). Genomic data from these pathogens have extended earlier work by paleopathologists. There have been efforts to sequence the genomes of additional ancient pathogens, with the potential to broaden our understanding of the infectious disease burden common to past populations from the Bronze Age to the early 20th century. In this review we describe the state-of-the-art of this rapidly developing field, highlight the contributions of ancient pathogen genomics to multidisciplinary endeavors and describe some of the limitations in resolving questions about the emergence and long-term evolution of pathogens.

Multi-omic detection of Mycobacterium leprae in archaeological human dental calculus.

Mineralized dental plaque (calculus) has proven to be an excellent source of ancient biomolecules. Here we present a Mycobacterium leprae genome (6.6-fold), the causative agent of leprosy, recovered via shotgun sequencing of sixteenth-century human dental calculus from an individual from Trondheim, Norway. When phylogenetically placed, this genome falls in branch 3I among the diversity of other contemporary ancient strains from Northern Europe. Moreover, ancient mycobacterial peptides were retrieved via mass spectrometry-based proteomics, further validating the presence of the pathogen. Mycobacterium leprae can readily be detected in the oral cavity and associated mucosal membranes, which likely contributed to it being incorporated into this individual's dental calculus. This individual showed some possible, but not definitive, evidence of skeletal lesions associated with early-stage leprosy. This study is the first known example of successful multi-omics retrieval of M. leprae from archaeological dental calculus. Furthermore, we offer new insights into dental calculus as an alternative sample source to bones or teeth for detecting and molecularly characterizing M. leprae in individuals from the archaeological record. This article is part of the theme issue 'Insights into health and disease from ancient biomolecules'.

2000-year-old pathogen genomes reconstructed from metagenomic analysis of Egyptian mummified individuals.

BACKGROUND: Recent advances in sequencing have facilitated large-scale analyses of the metagenomic composition of different samples, including the environmental microbiome of air, water, and soil, as well as the microbiome of living humans and other animals. Analyses of the microbiome of ancient human samples may provide insights into human health and disease, as well as pathogen evolution, but the field is still in its very early stages and considered highly challenging. RESULTS: The metagenomic and pathogen content of Egyptian mummified individuals from different time periods was investigated via genetic analysis of the microbial composition of various tissues. The analysis of the dental calculus' microbiome identified Red Complex bacteria, which are correlated with periodontal diseases. From bone and soft tissue, genomes of two ancient pathogens, a 2200-year-old Mycobacterium leprae strain and a 2000-year-old human hepatitis B virus, were successfully reconstructed. CONCLUSIONS: The results show the reliability of metagenomic studies on Egyptian mummified individuals and the potential to use them as a source for the extraction of ancient pathogen DNA.

Ancient dental pulp: Masterpiece tissue for paleomicrobiology.

INTRODUCTION: Dental pulp with special structure has become a good reference sample in paleomicrobiology-related blood-borne diseases, many pathogens were detected by different methods based on the diagnosis of nucleic acids and proteins. OBJECTIVES: This review aims to propose the preparation process from ancient teeth collection to organic molecule extraction of dental pulp and summary, analyze the methods that have been applied to detect septicemic pathogens through ancient dental pulps during the past 20 years following the first detection of an ancient microbe. METHODS: The papers used in this review with two main objectives were obtained from PubMed and Google scholar with combining keywords: "ancient," "dental pulp," "teeth," "anatomy," "structure," "collection," "preservation," "selection," "photography," "radiography," "contamination," "decontamination," "DNA," "protein," "extraction," "bone," "paleomicrobiology," "bacteria," "virus," "pathogen," "molecular biology," "proteomics," "PCR," "MALDI-TOF," "LC/MS," "ELISA," "immunology," "immunochromatography," "genome," "microbiome," "metagenomics." RESULTS: The analysis of ancient dental pulp should have a careful preparation process with many different steps to give highly accurate results, each step complies with the rules in archaeology and paleomicrobiology. After the collection of organic molecules from dental pulp, they were investigated for pathogen identification based on the analysis of DNA and protein. Actually, DNA approach takes a principal role in diagnosis while the protein approach is more and more used. A total of seven techniques was used and ten bacteria (Yersinia pestis, Bartonella quintana, Salmonella enterica serovar Typhi, Salmonella enterica serovar Paratyphi C, Mycobacterium leprae, Mycobacterium tuberculosis, Rickettsia prowazeki, Staphylococcus aureus, Borrelia recurrentis, Bartonella henselae) and one virus (Anelloviridae) were identified. Y. pestis had the most published in quantity and all methods were investigated for this pathogen, S. aureus and B. recurrentis were identified by three different methods and others only by one. The combining methods interestingly increase the positive rate with ELISA, PCR and iPCR in Yersinia pestis diagnosis. Twenty-seven ancient genomes of Y. pestis and one ancient genome of B. recurrentis were reconstructed. Comparing to the ancient bone, ancient teeth showed more advantage in septicemic diagnosis. Beside pathogen identification, ancient pulp help to distinguish species. CONCLUSIONS: Dental pulp with specific tissue is a suitable sample for detection of the blood infection in the past through DNA and protein identification with the correct preparation process, furthermore, it helps to more understand the pathogens of historic diseases and epidemics.

Osteoarcheological and biomolecular evidence of leprosy from an 11-13th century CE Muslim cemetery in Europe (Orosháza, Southeast Hungary).

Orosháza site no. 10 (Southeast Hungary) contains the partially excavated archaeological remains of an 11-13th century CE Muslim merchant village and its cemetery located in close proximity to Christian villages of the same era. The skeleton of a young woman (grave no. 16) from the last phase of the cemetery use was identified with rhinomaxillary lesions associated with lepromatous leprosy. The right parietal bone also exhibited signs of cranial trauma, possibly caused by symbolic trepanation, a well-known ritual practice in the 9-11th century CE Carpathian Basin. The retrospective diagnosis of the disease was supported by ancient DNA analysis, as the samples were positive for Mycobacterium leprae aDNA, shown to be of genotype 3. Contrary to the general practice of the era, the body of the young female with severe signs of leprosy was interred among the regular graves of the Muslim cemetery in Orosháza, which may reflect the unique cultural background of the community.

Paleomicrobiology: Diagnosis and Evolution of Ancient Pathogens.

The last century has witnessed progress in the study of ancient infectious disease from purely medical descriptions of past ailments to dynamic interpretations of past population health that draw upon multiple perspectives. The recent adoption of high-throughput DNA sequencing has led to an expanded understanding of pathogen presence, evolution, and ecology across the globe. This genomic revolution has led to the identification of disease-causing microbes in both expected and unexpected contexts, while also providing for the genomic characterization of ancient pathogens previously believed to be unattainable by available methods. In this review we explore the development of DNA-based ancient pathogen research, the specialized methods and tools that have emerged to authenticate and explore infectious disease of the past, and the unique challenges that persist in molecular paleopathology. We offer guidelines to mitigate the impact of these challenges, which will allow for more reliable interpretations of data in this rapidly evolving field of investigation.

Tuberculosis and leprosy associated with historical human population movements in Europe and beyond - an overview based on mycobacterial ancient DNA.

Context: Tuberculosis and leprosy are readily recognised in human remains due to their typical palaeopathology. Both Mycobacterium tuberculosis (MTB) and Mycobacterium leprae (ML) are obligate pathogens and have been detected in ancient human populations. Objective: To demonstrate historical tuberculosis and leprosy cases in Europe and beyond using molecular methods, as human populations are associated with different mycobacterial genotypes. Methods: MTB and ML ancient DNA (aDNA) has been detected by DNA amplification using PCR, or by whole genome sequencing. Mycobacterial cell wall lipids also provide specific markers for identification. Results: In 18th century Hungary, the European indigenous MTB genotype 4 strains have been found. However, many individuals were co-infected with up to three MTB sub-genotypes. In 8th-14th century Europe significant differences in ML genotypes were found between northwest Europe compared with central, southern, or eastern Europe. In addition, several co-infections of MTB and ML were detected in historical samples. Conclusion: Both MTB and ML strain types differ between geographically separate populations. This is associated with ancient human migration after an evolutionary bottleneck and clonal expansion. The absence of indigenous leprosy in Europe today may be due to the greater mortality of tuberculosis in individuals who are co-infected with both organisms.

Looking Backward To Move Forward: the Utility of Sequencing Historical Bacterial Genomes.

Many pathogens that caused devastating disease throughout human history, such as Yersinia pestis, Mycobacterium tuberculosis, and Mycobacterium leprae, remain problematic today. Historical bacterial genomes represent a unique source of genetic information and advancements in sequencing technologies have allowed unprecedented insights from this previously understudied resource. This minireview brings together example studies which have utilized ancient DNA, individual historical isolates (both extant and dead) and collections of historical isolates. The studies span human history and highlight the contribution that sequencing and analysis of historical bacterial genomes have made to a wide variety of fields. From providing retrospective diagnosis, to uncovering epidemiological pathways and characterizing genetic diversity, there is clear evidence for the utility of historical isolate studies in understanding disease today. Studies utilizing historical isolate collections, such as those from the National Collection of Type Cultures, the American Type Culture Collection, and the Institut Pasteur, offer enhanced insight since they typically span a wide time period encompassing important historical events and are useful for the investigating the phylodynamics of pathogens. Furthermore, historical sequencing studies are particularly useful for looking into the evolution of antimicrobial resistance, a major public health concern. In summary, although there are limitations to working with historical bacterial isolates, especially when utilizing ancient DNA, continued improvement in molecular and sequencing technologies and the resourcefulness of investigators mean this area of study will continue to expand and contribute to the understanding of pathogens.

Ancient DNA study reveals HLA susceptibility locus for leprosy in medieval Europeans.

Leprosy, a chronic infectious disease caused by Mycobacterium leprae (M. leprae), was very common in Europe till the 16th century. Here, we perform an ancient DNA study on medieval skeletons from Denmark that show lesions specific for lepromatous leprosy (LL). First, we test the remains for M. leprae DNA to confirm the infection status of the individuals and to assess the bacterial diversity. We assemble 10 complete M. leprae genomes that all differ from each other. Second, we evaluate whether the human leukocyte antigen allele DRB1*15:01, a strong LL susceptibility factor in modern populations, also predisposed medieval Europeans to the disease. The comparison of genotype data from 69 M. leprae DNA-positive LL cases with those from contemporary and medieval controls reveals a statistically significant association in both instances. In addition, we observe that DRB1*15:01 co-occurs with DQB1*06:02 on a haplotype that is a strong risk factor for inflammatory diseases today.

Leprosy in a Lombard-Avar cemetery in central Italy (Campochiaro, Molise, 6th-8th century AD): ancient DNA evidence and demography.

BACKGROUND: The study of past infectious diseases increases knowledge of the presence, impact and spread of pathogens within ancient populations. AIM: Polymerase chain reaction (PCR) was used to examine bones for the presence of Mycobacterium leprae ancient DNA (aDNA) as, even when leprosy is present, bony changes are not always pathognomonic of the disease. This study also examined the demographic profile of this population and compared it with two other populations to investigate any changes in mortality trends between different infectious diseases and between the pre-antibiotic and antibiotic eras. SUBJECTS AND METHODS: The individuals were from a site in Central Italy (6th-8th CE) and were examined for the presence of Mycobacterium leprae aDNA. In addition, an abridged life mortality table was constructed. RESULTS: Two individuals had typical leprosy palaeopathology, and one was positive for Mycobacterium leprae aDNA. However, the demographic profile shows a mortality curve similar to that of the standard, in contrast to a population that had been subjected to bubonic plague. CONCLUSIONS: This study shows that, in the historical population with leprosy, the risk factors for health seem to be constant and distributed across all age classes, similar to what is found today in the antibiotic era. There were no peaks of mortality equivalent to those found in fatal diseases such as the plague, probably due to the long clinical course of leprosy.

Microbial Genomics of Ancient Plagues and Outbreaks.

The recent use of next-generation sequencing methods to investigate historical disease outbreaks has provided us with an unprecedented ability to address important and long-standing questions in epidemiology, pathogen evolution, and human history. In this review, we present major findings that illustrate how microbial genomics has provided new insights into the nature and etiology of infectious diseases of historical importance, such as plague, tuberculosis, and leprosy. Sequenced isolates collected from archaeological remains also provide evidence for the timing of historical evolutionary events as well as geographic spread of these pathogens. Elucidating the genomic basis of virulence in historical diseases can provide relevant information on how we can effectively understand the emergence and re-emergence of infectious diseases today and in the future.