Volume 4, Number 1—March 1998
Ixodes dammini: A Junior Synonym for Ixodes scapularis
To the Editor: The authors of "A new tick-borne encephalitis-like virus infecting New England deer ticks, Ixodes dammini" (1) provide useful information regarding a possibly new tick-borne encephalitis-like virus. However, the use of the name Ixodes dammini is not accurate for describing this species. I. dammini (Spielman, Clifford, Piesman, and Corwin) was synonymized with Ixodes scapularis (Say) in 1993 by Oliver et al. (2) and was redescribed in 1996 (3) to reduce confusion regarding identification. Keirans and colleagues summarize a wide array of rigorous studies involving hybridization, assortative mating, isozymes, and morphometrics, all of which provide evidence supporting the synonymization of the two tick species (3).
The synonymization of I. dammini with I. scapularis has been widely accepted. "I. scapularis (= I. dammini)" is still often used, but the use of I. scapularis as the sole nomen for this species is becoming more common (4). Oliver et al. (2) have established I. dammini as a junior subjective synonym of I. scapularis. If scientifically rigorous evidence exists justifying the reestablishment of the species name I. dammini, it must be published according to proper procedure. The proper nomenclature of any species, let alone one of such widespread notoriety and public health importance, is too important to be relegated to a footnote. Until such evidence is presented, the continued misuse of I. dammini serves only to confuse health-care providers, public health professionals, and lay persons.
On a secondary matter, on page 167 of the dispatch, the authors state that "I. (Pholeoixodes) cookei is a one-host tick that is only distantly related to I. dammini and only rarely feeds on humans or mice" (1). I. cookei is a three-host tick (D.E. Sonenshine, pers. comm.), as are all the members of the genus Ixodes.
- Telford SR III, Armstrong PM, Katavolos P, Foppa I, Garcia ASO, Wilson ML, A new tick-borne encephalitis-like virus infecting New England deer ticks, Ixodes dammini. Emerg Infect Dis. 1997;3:165–70.
- Oliver JH, Owsley MR, Hutcheson AM, James C, Chen W, Irby S, Conspecificity of the ticks Ixodes scapularis and Ixodes dammini (Acari: Ixodidae). J Med Entomol. 1993;30:54–63.
- Keirans JE, Hutcheson HJ, Durden LA, Klompen JSH. Ixodes scapularis (Acari: Ixodidae): redescription of all active stages, distribution, hosts, geographical variation, and medical and veterinary importance. J Med Entomol. 1996;33:297–318.
- Centers for Disease Control and Prevention. Lyme disease—United States, 1996. MMWR Morb Mortal Wkly Rep. 1997;46:531–5.