This study illustrates that ticks in CR carry a wide variety of infectious pathogens.

A total of 549 subadult ticks of three species Ixodes
arboricola (75.0%), Ixodes ricinus (23.1%), and Haemaphysalis concinna
(1.8%) were collected from 20 species of birds (Passeriformes).
Rickettsiae were detected in 44.0% larvae and 24.5% nymphs of I.
arboricola

Excerpt:

Purpose: Limited data exist on differences of erythema migrans patients with either positive or negative Borrelia burgdorferi sensu lato skin culture.

Methods: We analyzed 252 adult patients with erythema migrans in whom skin biopsy specimen was cultured for the presence of B. burgdorferi sensu lato. Evaluations of epidemiological, clinical, and microbiological findings were conducted at baseline, 14 days, 2, 6, and 12 months after treatment with either doxycycline or cefuroxime axetil.

Results: One hundred fifty-one (59.9%) patients had positive skin culture (86.9% B. afzelii, 8.0% B. garinii, 5.1% B. burgdorferi sensu stricto) and 101 (40.1%) had negative skin culture. Patients in the culture-positive and culture-negative groups were comparable for the basic demographic, epidemiological, clinical, and laboratory characteristics at presentation. Statistically significantly worse selected treatment outcome parameters in the culture-positive group compared with the culture-negative group were established during follow-up. Treatment failure was documented in two patients who were culture positive and in none in the culture-negative group.

Conclusions: Although findings for the pretreatment characteristics were comparable between the erythema migrans skin culture-positive and culture-negative patients, some parameters indicate that borrelia skin culture positivity may predict a less-favorable treatment outcome.

A quantitative real-time polymerase chain reaction assay to detect and quantify a portion of the outer membrane protein B gene (ompB) of Rickettsia amblyommii was employed to assess the threat of R. amblyommii exposure to humans parasitized by Amblyomma americanum (the lone star tick).

A total of 72 pools of lone star ticks removed from humans were acquired from two collections and used in this study: 44 pools of A. americanum submitted to the Department of Defense Human Tick Test Kit Program in 2003 collected from 220 individuals from 14 states, and 28 pools of A. americanum representing 120 ticks obtained from boy scouts and adult leaders at the Boy Scouts of America National Jamboree held at Fort A.P. Hill, Virginia, in 2005.

Of the 72 lone star tick pools representing 340 lone star ticks, 58 pools (80.5%) were positive for R. amblyommii. In addition, individual A. americanum ticks parasitizing humans collected as part of the Department of Defense Human Tick Test Kit Program in 2002 and 2003 from 17 states were evaluated. It was found that 244 of 367 (66.5%) individual A. americanum ticks tested positive for the presence of R. amblyommii DNA. These results clearly show that lone star ticks parasitizing humans are highly infected with R. amblyommii, which may potentiate rickettsial infection of and possibly disease in humans.

Benoit VM, Petrich A, Alugupalli KR, Marty-Roix R, Moter A, Leong JM, Boyartchuk VL.

Department of Molecular Genetics and Microbiology, and Program in Gene Function and Expression, University of Massachusetts Medical School, Worcester, MA 01605; Institut für Mikrobiologie und Hygiene, Charité – Universitätsmedizin Berlin, Campus Charité Mitte, 10117 Berlin, Germany; Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA 19107.

Host susceptibility to infection is controlled in large measure by the genetic makeup of the host. Spirochetes of the genus Borrelia include nearly 40 species of vector-borne spirochetes that are capable of infecting a wide range of mammalian hosts, causing Lyme disease and relapsing fever. Relapsing fever is associated with high-level bacteremia, as well as hematologic manifestations such as thrombocytopenia (i.e. low platelet numbers) and anemia. To facilitate studies of genetic control of susceptibility to Borrelia hermsii infection we performed a systematic analysis of the course of infection using immunocompetent and immunocompromised inbred strains of mice. Our analysis revealed that sensitivity to B. hermsii infections is genetically controlled. In addition, whereas the role of adaptive immunity to relapsing fever spirochetes is well documented, we found that innate immunity contributes significantly to reduction of bacterial burden. Similar to human infection, progression of the disease in mice was associated with thrombocytopenia and anemia. Histological and fluorescence in situ hybridization (FISH) analysis of infected tissues indicated that red blood cells were removed by tissue resident macrophages, a process that could lead to anemia. Spirochetes in the spleen and liver were often visualized associated with RBCs, lending support to the hypothesis that direct interaction of B. hermsii spirochetes with RBCs leads to clearance of bacteria from the bloodstream by tissue phagocytes.

PMID: 19995898 [PubMed – as supplied by publisher]