Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland USA
Address for correspondence: J. Stephen Dumler, M.D., Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 624, Baltimore, MD 21205. Voice: 410-955-8654; fax: 443-287-3665. sdumler{at}jhmi.edu
Human and animal infections by
Anaplasmataceae are increasingly
recognized as important and potentially fatal arthropod-transmitted
diseases. Since the first recognition and implementation of
diagnostic methods for human infection by
Ehrlichia chaffeensis and
Anaplasma phagocytophilum, the incidence of infections has
linearly increased. Moreover, diagnostic and epidemiological
testing indicates that "ehrlichia" infections are globally distributed
and suggests that additional agents of human and veterinary
"ehrlichiosis" will be identified. With increasing disease identification
has come recognition that the infections can be severe, with
approximately one-half of patients requiring hospitalization
for complications including respiratory distress, myocarditis,
neurological complications, hepatitis, a septic or toxic shock-like
disease, opportunistic infections, and death in 0.5 to 3.0%.
An understanding of the diseases, pathophysiology, pathogenesis,
control, and management will best be developed through fundamental
investigations. Advances in comprehension as to the separate
contributions of bacteria and host are crucial since most data
now suggest that alterations in host neutrophil function and
protection from innate and adaptive immunity also contribute
to disease manifestations. It is reasonable to operate from
the hypothesis that these host cell functional changes ultimately
benefit bacterial survival while inadvertently eliciting clinical
disease in poorly adapted hosts. A firmer basis for the scientific
understanding of
Anaplasmataceae biology will allow logical
and rational approaches toward infection control, prevention,
and treatment.
