ロシア極東のイルクーツクにある研究所で未知の肺炎により研究員が死亡したというニュースがこのところ注目されています。
重症の肺炎と見られる症状により2人が死亡と報道されていますが、研究所内での感染が考えられるものの感染原因等については分かっていないようです。トランプ米大統領もこの件には重大な関心を寄せていると報じられていますが、新型コロナウィルスの感染拡大を彷彿とさせる不気味さがあります。
感染原因、感染経路ともに不明という肺炎について、WHOは、"pneumonia of undetermined etiology"という難しい言葉を使っています。"etiology"とは因果関係学、原因論という意味の単語です。
On 2 October 2026, WHO became aware through media reports of the death of an employee of the Irkutsk Antiplague Research Institute (APRI) of Siberia and the Far East, the Russian Federation. According to these reports, the individual died on 2 October following hospitalization for severe pneumonia on 29 September, and pneumonic plague was suspected as the cause of death, following occupational exposure in laboratory settings. Following requests for verification from WHO, the National Focal Point for the International Health Regulations (2005) (NFP) of the Russian Federation confirmed the death and informed WHO that no case of plague had been registered recently in Irkutsk Oblast, that preventive and control measures had been implemented in accordance with national sanitary legislation, and that the laboratory testing of contacts detected no high-threat pathogens.
(中略)
Based on the information provided by NFP, WHO has not identified evidence of ongoing transmission associated with this event. However, confidence in the assessment remains limited by the absence of a confirmed etiological diagnosis, and the remaining uncertainty regarding the source and mode of exposure.
(中略)
As the etiology of the fatal illness remains undetermined, further investigation of available clinical specimens and epidemiological information should continue, as appropriate.
(Pneumonia of undetermined etiology - Russian Federation. Disease Outbreak News. WHO. October 10, 2026.)
学問を意味する接尾辞-logyがついた英単語のほとんどがギリシャ語由来であるように、"etiology"という単語も、原因(cause)を意味するギリシャ語aitiaに由来し、ギリシャ語aitiologiaがラテン語aetiologiaを経て英語になったものです。