- Daniel J Sexton, MD
Daniel J Sexton, MD
- Editor-in-Chief — Infectious Diseases
- Section Editor — Bacterial Infections
- Professor of Medicine
- Duke University Medical Center
Rickettsialpox is an uncommon, mite-borne rickettsial disease caused by the agent Rickettsia akari. R. akari was first isolated in 1946 from a patient, mites, and a naturally infected house mouse in Queens, New York . The disease was named rickettsialpox because of its resemblance to chickenpox. The etiologic agent was named R. akari because the causative agent belonged to the genus Rickettsia and because akari is Greek for "mite." R. akari is a member of the spotted fever group of rickettsiae of which Rickettsia rickettsii is the prototype. (See "Biology of Rickettsia rickettsii infection".)
R. akari is transmitted to the common house mouse (Mus musculus) by the bloodsucking mite Liponyssoides sanguineus (formerly Allodermanyssus sanguineus). The mouse serves as the reservoir for the disease. L. sanguineus is a small (0.75 to 1.5 mm), colorless arthropod that swells to many times its normal size after a blood meal and becomes bright red in color. L. sanguineus rarely bites humans when mice are plentiful. However, when mouse populations are reduced (eg, by vermin eradication programs), this mite will bite humans and transmit the disease. Although natural infection is thought to occur exclusively by the bite of an infected mite, transmission has occurred in laboratory settings via inhalation of infectious aerosols .
Occurrence — Rickettsialpox has been detected in urban areas in New York, Pittsburgh, Cleveland, Boston, as well as Arizona, Utah, South Africa and the Ukraine. Although over 800 cases of rickettsialpox have been reported since the initial description of the infection in 1946, it is widely assumed that this infection is underrecognized and underreported [3,4]. Rickettsialpox has also been described in homeless patients and in persons who use intravenous drugs .
Rickettsialpox may have a wider geographic occurrence than previously realized. For example, R. akari was isolated from a 36 year old man from Croatia, an area in which rickettsialpox had not been previously recognized . Similarly, others have speculated that R. akari is widespread in Europe [7,8]. In another report, sera reactive with R. akari antigens were detected among patients from Mexican states of Yucatan and Jalisco who were initially thought to have dengue fever . Another serosurvey done in southern California suggested that R. akari or an akari-like rickettsiae are present in wild rodents in Orange County, California . A single case of rickettsialpox was diagnosed in a man who worked at a suburban golf course in North Carolina .
Incubation period — The incubation period for rickettsialpox has not been conclusively established but is thought to range from 10 to 14 days. One patient developed fever nine days after an apparent single exposure to a known focus of infection. In a second, laboratory-acquired case, a primary lesion at the site of inoculation appeared on the seventh day and fever appeared ten days after exposure .
- Public Health Weekly Reports for NOVEMBER 8, 1946. Public Health Rep 1946; 61:1605.
- SLEISENGER MH, MURRAY ES, COHEN S. Rickettsialpox case due to laboratory infection. Public Health Rep 1951; 66:311.
- Kass EM, Szaniawski WK, Levy H, et al. Rickettsialpox in a New York City hospital, 1980 to 1989. N Engl J Med 1994; 331:1612.
- Koss T, Carter EL, Grossman ME, et al. Increased detection of rickettsialpox in a New York City hospital following the anthrax outbreak of 2001: use of immunohistochemistry for the rapid confirmation of cases in an era of bioterrorism. Arch Dermatol 2003; 139:1545.
- Brouqui P, Raoult D. Arthropod-borne diseases in homeless. Am J Trop Med Hyg 2006; 1078:223.
- Radulovic S, Feng HM, Morovic M, et al. Isolation of Rickettsia akari from a patient in a region where Mediterranean spotted fever is endemic. Clin Infect Dis 1996; 22:216.
- Brouqui P, Parola P, Fournier PE, Raoult D. Spotted fever rickettsioses in southern and eastern Europe. FEMS Immunol Med Microbiol 2007; 49:2.
- Paddock CD, Koss T, Eremeeva ME, et al. Isolation of Rickettsia akari from eschars of patients with rickettsialpox. Am J Trop Med Hyg 2006; 75:732.
- Zavala-Velazquez JE, Yu XJ, Walker DH. Unrecognized spotted fever group rickettsiosis masquerading as dengue fever in Mexico. Am J Trop Med Hyg 1996; 55:157.
- Bennett SG, Comer JA, Smith HM, Webb JP. Serologic evidence of a Rickettsia akari-like infection among wild-caught rodents in Orange County and humans in Los Angeles County, California. J Vector Ecol 2007; 32:198.
- Krusell A, Comer JA, Sexton DJ. Rickettsialpox in North Carolina: a case report. Emerg Infect Dis 2002; 8:727.
- ROSE HM. The clinical manifestations and laboratory diagnosis of rickettsialpox. Ann Intern Med 1949; 31:871.
- Greenberg M, Pellitteri O. Rickettsialpox. Bull N Y Acad Med 1947; 23:338.
- Madison G, Kim-Schluger L, Braverman S, et al. Hepatitis in association with rickettsialpox. Vector Borne Zoonotic Dis 2008; 8:111.
- Walker DH, Gile GC, Feng HM, et al. Diagnosis of spotted fever group rickettsioses by immunohistology with a group-specific antlipopolysaccharide monoclonal antibody (abstract). Lab Invest 1994; 70:128A.
- Denison AM, Amin BD, Nicholson WL, Paddock CD. Detection of Rickettsia rickettsii, Rickettsia parkeri, and Rickettsia akari in skin biopsy specimens using a multiplex real-time polymerase chain reaction assay. Clin Infect Dis 2014; 59:635.
- Sanders S, Di Costanzo D, Leach J, et al. Rickettsialpox in a patient with HIV infection. J Am Acad Dermatol 2003; 48:286.
- ROSE HM. The treatment of rickettsialpox with antibiotics. Ann N Y Acad Sci 1952; 55:1019.