Researchers have identified the earliest known instances of plague within hunter-gatherer populations near Lake Baikal, dating to approximately 5,500 years ago.

研究人員在貝加爾湖附近的狩獵採集人群中，發現了已知最早的鼠疫病例，時間約在 5,500 年前。

The discovery originated from the analysis of dental pulp samples from 46 individuals across four cemeteries along the Angara River. Utilizing shotgun sequencing, an international team identified Yersinia pestis DNA in 18 subjects. The prevalence rate at the Ust’-Ida I site is noted to be comparable to that of known medieval plague mass graves, suggesting a high level of community-wide infection.

此發現源於對沿安加拉河四座墓地中 46 個個體的牙髓樣本分析。一個國際團隊利用散彈槍定序技術，在 18 個樣本中發現了鼠疫桿菌（Yersinia pestis）的 DNA。Ust’-Ida I 遺址的盛行率與已知中世紀鼠疫大屠殺墓地相當，顯示當時社區整體的感染率極高。

Historically, epidemiological consensus posited that lethal plague outbreaks were contingent upon the transition to sedentary agricultural societies and the subsequent increase in population density and proximity to domestic animals. However, these findings indicate that highly virulent strains existed among mobile hunter-gatherers centuries prior to the Neolithic farming era. This suggests that the pathogen's lethality was not dependent on urban settlement patterns.

在歷史上，流行病學的共識認為，致命的鼠疫爆發取決於向定居農業社會的轉型，以及隨後的人口密度增加和與家畜接觸的緊密程度。然而，這些發現表明，在 Neolithic 農耕時代之前的數世紀，高致病性的菌株已存在於流動的狩獵採集者之中。這顯示病原體的致命性並不依賴於城市定居模式。

Genomic sequencing revealed that this ancestral strain lacked the specific genetic markers required for the formation of buboes and the murine toxin necessary for efficient flea-borne transmission. Consequently, it is hypothesized that the disease manifested as a pneumonic infection, facilitating human-to-human transmission via respiratory droplets. The presence of a superantigenic toxin is cited as the primary mechanism for the observed disproportionate mortality among children and adolescents, as their developing immune systems are more susceptible to the resulting systemic inflammatory overreaction.

基因組定序顯示，這種祖先菌株缺乏形成淋巴結腫大（buboes）所需的特定基因標記，以及有效經跳蚤傳播所需的鼠類毒素。因此，研究人員假設該疾病表現為肺炎感染，透過飛沫在人與人之間傳播。研究指出，超抗原毒素是導致兒童與青少年死亡率異常之高的主要機制，因為其發育中的免疫系統更容易對由此引起的全身性炎症過激反應產生反應。

Regarding the zoonotic origin, the researchers suggest a spillover event from marmots, which remain plague reservoirs in the region. The transmission likely occurred through direct contact during the hunting or processing of these rodents. This evidence supports the theory that the pathogen emerged in Central or North-East Asia before its subsequent dispersal across Eurasia.

關於動物源頭，研究人員認為是從旱兔（marmots）傳播而來，該動物至今仍是該地區的鼠疫宿主。傳播很可能是在狩獵或處理這些齧齒類動物時，透過直接接觸而發生。此證據支持了病原體先在中亞或東北亞出現，隨後才傳播至歐亞大陸的理論。

The study establishes that lethal plague outbreaks occurred in prehistoric Siberia 5,500 years ago, predating the agricultural era and utilizing different transmission mechanisms than later bubonic strains.

研究證實 5,500 年前的史前西伯利亞曾出現致命鼠疫爆發，早於農業時代，且傳播機制與後來的腺鼠疫菌株不同。