Identification of viral DNA (Anelloviridae) in a 200-year-old dental pulp sample (Napoleon's Great Army, Kaliningrad, 1812)

Ancient human remains are potential sources of biological information including traces of past infections, since previous studies have demonstrated the effective detection of several bacterial agents or host-integrated viruses in old biological remnants like tissues or teeth. Studies of skeletal dental pulp samples are of particular interest since this location is potentially exposed to bloodborne agents during life through its vascularization, and could be considered as well preserved from environment after death of the host. DNA viruses belonging to the family Anelloviridae are highly present in human populations where they harbor an extreme genetic diversity but a yet undefined implication in hosts' health. We hypothesized that anelloviruses would be detected in ancient remains and that they may also serve as tracer viruses for the study of other viral agents. We analyzed 200-year-old dental pulp samples from remains of soldiers of Napoleon's Great Army during the Russian Retreat. Successful detection of Anelloviridae DNA by PCR was obtained for 1/21 ancient samples tested. The sequence identified showed 23% nucleotide divergence with the closest group of modern isolates (genus Gammatorquevirus), and was confirmed as phylogenetically distinct from those identified in saliva samples from the two investigators in charge of the study (genera Alphatorquevirus and Betatorquevirus). PCR directed toward the human beta globin gene was also performed. Negative controls were negative. Our results demonstrate that an ubiquitary, non-integrated, DNA virus is detectable from ancient biological material, with potential developments in terms of evolution studies or subsequent molecular investigations involving further viral agents.

Research highlights▶ Viruses belonging to the family Anelloviridae are highly present in human populations. ▶ We hypothesized that they could be detected in 200-year-old dental pulp samples. ▶ Successful viral DNA amplification (∼120 bp) was obtained for 1/21 samples. ▶ The sequence showed 23% genetic divergence with the closest group of modern isolates. ▶ Anelloviruses may represent tracer viruses for future microbiological investigations.