Legionnaires' Disease

The Sophistry of the Term “Legionnaires’ Disease” F. WILLIAM SUNDERMAN, M.D., Ph.D.

Institute for Clinical Science, Hahnemann Medical College and Hospital, Philadelphia, PA 19102

In January 1977, the Center for Dis lungs of patients who suffer from ease Control (CDC) of the federal gov pneumonitis caused by a variety of toxic ernment announced1,2 that its scientists and infectious agents as well as from de had isolated a bacteria-like organism that bilitating diseases. appeared to cause the outbreak of It is our present view that the respira Legionnaires’ Disease. The published tory outbreak that occurred in Philadel scientific evidence that formed the basis phia in July 1976 was caused by a toxic of this announcement was limited. In ad agent and that many of the victims de dition, a preliminary report has recently veloped secondary pulmonary infections been transmitted by CDC (September by microbes that probably"include the one 1977) to directors of state and territorial described by CDC. Briefly stated, the be public health laboratories. lief that Pennsylvania Legionnaires’ Dis Within the past few months, the com ease was caused by a chemical toxin is munications media have frequently re based upon the following observations: ported the occurrence of sporadic cases of 1. The history, symptoms, physical so-called “Legionnaires’ Disease” attri findings, laboratory studies and buted to the organism isolated by CDC. course of the Philadelphia outbreak As a result of these reports, physicians and the public have been led into believing conformed closely to those pro duced by the inhalation of a toxic that the CDC organism has been shown to agent, such as nickel carbonyl. The be primarily responsible for the outbreak fever that occurred in many of the of the illness among Pennsylvania Legionnaires and guests during their con victims was consistent with that ob vention in Philadelphia in July 1976. The served in infections secondary to chemical pneumonitis. conclusion that the cause of Pennsylvania Legionnaires’ Disease has been estab 2. The summarization report3 of the lished and that the mystery has finally panel of 12 pathologists assembled been solved is unwarranted. It bespeaks by CDC to review the necropsy of sophistry,—a type of reasoning that is material from victims of the superficially plausible but may be, in fact, Philadelphia outbreak concluded delusive. Thus, in their communications, that the lung lesions were probably CDC neglected to present the alternative produced by a toxic agent and that hypothesis that their microbe is a sec the possibility of an infectious ori ondary invader that may proliferate in the gin was remote. The panel of 2 SUNDERMAN

pathologists also noted that foci of trations of nickel in lung tissues of secondary pneumonia were present the victims of the Philadelphia out in the lungs of a number of the break. These independent inves cases. Furthermore, a comparison of tigators reported the average nickel histopathologic sections of lung tis concentration in lung tissues from sue from Legionnaires’ Disease the Legionnaire cases to be nine with those of patients with fatal times that of the controls. Their high acute nickel carbonyl poisoning re nickel values were considered to be veals the lesions to be essentially “inconclusive,” owing to possible identical.4 The pathologic evidence contamination. Chen and coworkers supports the view that the primary made their analyses on nine cases of cause of Pennsylvania Legion Legionnaires’ Disease, on nine naires’ Disease was a toxic agent cases referred to as “controls” and and that the organism isolated by on three cases of pneumonia. The CDC might be a secondary invader. tissues were obtained from CDC 3. The outbreak was not contagious and were coded so that the analysts and the mode of transmission has did not know in advance the origin not been established. It seems un of the tissues or the provisional likely that an organism would be diagnoses. It is noteworthy that capable of infecting solely Pennsyl eight of the nine lung tissues from vania Legionnaires and their guests the Legionnaire cases were the only among the many thousands of bicen ones that yielded the high nickel tennial visitors in Philadelphia, in values. If the increased concen addition to the normal population of trations of nickel in the lungs of the city, and to single out and pro Legionnaire cases are attributed to duce in the Pennsylvania Legion contamination, then the cause must naires a respiratory disease which in be determined for the non itself was not contagious. On the contamination of tissues from the other hand, exposure of the “controls” and pneumonia cases. Pennsylvania Legionnaires at the The high concentrations of nickel Bellevue Stratford Hotel to an in obtained in the lung tissues from haled chemical toxin presents a Legionnaire cases cannot be dismis more plausible hypothesis for the sed on the basis of preferential con outbreak. tamination. 4. Since the symptoms and physical The initial investigations of the findings of the victims conformed to Philadelphia outbreak by the public those of patients with acute nickel health authorities were concentrated carbonyl poisoning, nickel analyses primarily on efforts to establish a diag were undertaken on tissues ob nosis of swine influenza. The failure of tained at necropsy from the victims. the authorities to emphasize chemical tox The nickel concentrations in the ins as possible factors in the early stages lungs of five of six subjects, reported represents a serious flaw in the scientific by Sunderman, Jr. and Baselt,5,6 investigations. If samples of excreta and were several fold greater than the blood had been saved for analyses, a con nickel concentration of normal lung firmed cause might have been ascer tissue. tained. It is now doubtful that the pri Later, Chen, Francisco and Mil mary cause of the Philadelphia outbreak ler7 confirmed the high concen- will ever be established with certainty. THE SOPHISTRY OF THE TERM “LEGIONNAIRES’ DISEASE” 3

The available facts simply do not war 3. Pathology of “Legionnaires’ Disease”. rant acceptance of the conclusion that Memorandum from Director of Pathology Divi sion and Staff Pathologist, Toxicology Branch, the CDC organism, was the primary CDC to Director for Disease Control, Atlanta, cause of the outbreak. GA, September 17, 1976. In the interest of scientific accuracy 4. SUNDERMAN, F. WILLIAM: Perspectives on and to avoid sophistry, the microbe iden Legionnaires’ Disease in relation to acute nickel carbonyl poisoning. The Henry M. Scharf Lec tified by CDC should be given a provi ture on Current Affairs. Ann. Clin. Lab. Sci. sional generic name and the illness attri 7:187-200, 1977. buted to this organism should then be de 5. Sunderman, F. W., Jr . and Ba selt, R. C.: Final report on measurements of nickel concentration signated by citation. For example, if the in tissue and urine specimens from victims of organism were a rickettsia, the illness “Legionnaires’ Disease”. Submitted to Bureau should be referred to as a rickettsiosis. It of Laboratories of Health, Commonwealth of is a misnomer and a misrepresentation to Pennsylvania, September 20, 1976. 6. “Legionnaires’ Disease”. Hearings before the use the term “Legionnaires’ Disease” in Subcommittee on Consumer Protection and reference to patients other than the vic Finance of the Committee on Interstate and tims of the 1976 Philadelphia outbreak. Foreign Commerce. House of Representatives, Ninety-fourth Congress, Second Session. For the Purpose of Discussing the Causative Fac References tors of the “Legionnaires’ Disease”. November 1. Special issue. Epidemiologic notes and reports: 23 and 24, 1976. U.S. Government Printing Follow-up on respiratory illness—Philadelphia Office, Serial No. 94-159, Washington, DC, Morbidity and Mortality Weekly Report, Center 1977. for Disease Control 26:9-11, 1977. 7. C h e n , J. R., F rancisco, R. B., and Mil l e r , T. 2. “Legion disease” cause found; puzzles linger. E.: Legionnaires’ Disease: nickel levels. Sci A.M.A. Med. News, January 1977. ence i 96:906-908, 1977.