You may have thought that Orin Scrivello was the worst dentist ever. Well, have I got a story for you. This dentist isn’t a sadist, and his follies were far from intentional. But the implications of his conduct greatly affected the lives of at least five of his patients. This week’s Phylogeny Friday is story fit for CSI. Learn about the dentist, the virus, and his patients below the fold.
The story revolves around Dr. David Acer, a Florida dentist who died in 1990 from complications of AIDS. Dr. Acer’s death would have been far from remarkable at the time — the AIDS epidemic was quite visible by the late 1980s, and one death earned no more attention than any other. Dr. Acer’s story, however, extends beyond his private life and into his practice. You see, Dr. Acer had multiple patients that had been diagnosed as infected with HIV within a couple of years of his death.
Many of the infected patients showed no risk factors associated with HIV infection. One elderly woman (hardly the at risk type that Tara described) had been married for more than 25 (her spouse was HIV negative), had never used intravenous drugs, never had sex with any at risk individuals, and never received a blood transfusion. Another patient was not an intravenous drug user, had no history of transfusion, and all recent sexual contacts were HIV negative.
A phylogeny created using DNA sequences of the HIV virus taken from the dentist, patients, and other individuals within a 90 mile radius is shown below. Note the cluster containing sequences from the Dentist, Patient A, Patient B (the elderly woman), and Patient C (the second patient described above).
The sequences in the boxed cluster differ by an average of 3.4%, consistent with HIV strains obtained from a single person or HIV strains from individuals who share a common source of infection. The genetic relatedness of the strains, along with other corroborating evidence, presents a strong case that the dentist somehow transmitted the virus to multiple patients. Subsequent analyses revealed other patient to whom the dentist transmitted HIV, though not all of the Dr. Acer’s HIV positive patients obtained the virus from the dentist (e.g., Patient D).
To the best of my knowledge, no one has yet to present a clear picture of how the dentist transmitted the virus to his patients. It is possible that he sustained small abrasions while operating on patients which allowed his blood to enter the patients’ mouths. Even though we lack a clear mechanism, the evidence strongly supports the hypothesis that Dr. Acer is the source of some of his patients’ HIV infections.
Some news outlets expressed skepticism regarding the conclusions reached by the CDC. A response to the news coverage surrounding the investigation can be found here.
Centers for Disease Control. 1991. Update: Transmission of HIV infection during an invasive dental procedure. MMWR 40(2): 23-27, 33.
Ciesielski et al. 1992. Transmission of human immunodeficiency virus in a dental practice. Ann. Intern. Med. 116(10):798-805.