- Update on Tick-Borne Bacterial Diseases in Travelers. [Review]
- CICurr Infect Dis Rep 2018 May 22; 20(7):17
- Ticks are the second most important vectors of infectious diseases after mosquitoes worldwide. The growth of international tourism including in rural and remote places increasingly exposes travelers ...
Ticks are the second most important vectors of infectious diseases after mosquitoes worldwide. The growth of international tourism including in rural and remote places increasingly exposes travelers to tick bite. Our aim was to review the main tick-borne infectious diseases reported in travelers in the past 5 years.
- Epidemiology of Acute Febrile Illness in Latin America. [Review]
- CMClin Microbiol Infect 2018 May 16
- CONCLUSIONS: DENV is the febrile illness most frequently reported, reflecting its importance, while CHIKV and ZIKV present increasing trends since its emergence in the region. Studies with systematic and harmonized approach for detection of multiple pathogens are needed and would probably reveal a higher burden of neglected pathogens such as Rickettsia spp. and arenaviruses. The lack of point-of-care tests and harmonized approach limits the care provided by health professionals and the efficacy of surveillance for AFI in the region.
- Shifts in Borrelia burgdorferi (s.l.) geno-species infections in Ixodes ricinus over a 10-year surveillance period in the city of Hanover (Germany) and Borrelia miyamotoi-specific Reverse Line Blot detection. [Journal Article]
- PVParasit Vectors 2018 May 18; 11(1):304
- CONCLUSIONS: Long-term monitoring is an essential part of public health risk assessment to capture data on pathogen occurrence over time. Such data will reveal shifts in pathogen geno-species distribution and help to answer the question whether or not climate change influences tick-borne pathogens.
- Rickettsia parkeri in Dermacentor parumapertus Ticks, Mexico. [Journal Article]
- EIEmerg Infect Dis 2018; 24(6):1108-1111
- During a study to identify zoonotic pathogens in northwestern Mexico, we detected the presence of a rickettsial agent in Dermacentor parumapertus ticks from black-tailed jackrabbits (Lepus californic...
During a study to identify zoonotic pathogens in northwestern Mexico, we detected the presence of a rickettsial agent in Dermacentor parumapertus ticks from black-tailed jackrabbits (Lepus californicus). Comparison of 4 gene sequences (gltA, htrA, ompA, and ompB) of this agent showed 99%-100% identity with sequences of Rickettsia parkeri.
- Prevalence of Rickettsia Species (Rickettsiales: Rickettsiaceae) in Dermacentor variabilis Ticks (Acari: Ixodidae) in North Carolina. [Journal Article]
- JMJ Med Entomol 2018 May 16
- The American dog tick, Dermacentor variabilis (Say), is a vector of spotted fever group (SFG) rickettsiae, including Rickettsia rickettsii the causative organism of Rocky Mountain spotted fever (RMSF...
The American dog tick, Dermacentor variabilis (Say), is a vector of spotted fever group (SFG) rickettsiae, including Rickettsia rickettsii the causative organism of Rocky Mountain spotted fever (RMSF). In North Carolina, SFG rickettsioses (including RMSF) are a leading cause of tick-borne illness. Knowledge of the infection rate and geographic distribution of D. variabilis ticks infected with Rickettsia spp. provides information on the spatial distribution of public health risk. Accordingly, we extracted genomic DNA from adult D. variabilis collected from field habitats in 32 North Carolina counties from 2009 to 2013. A nested PCR assay of the 23S-5S intergenic spacer (IGS) region of Rickettsia coupled with reverse line blot hybridization (RLBH) with species-specific probes was used to detect and identify rickettsiae to species. Approximately half of the 532 tick DNA samples exhibited a band of the expected size on agarose gels, indicating infection with Rickettsia spp. RLBH analyses showed R. amblyommatis (formerly 'Candidatus R. amblyommii'), R. parkeri, and R. montanensis were predominant, while other Rickettsia species detected included R. conorii-like, R. massiliae, R. rhipicephali, R. canadensis, R. bellii, and some unknown Rickettsia spp. Some ticks were infected with more than one Rickettsia species. Notably, several Rickettsia-positive ticks harbored R. rickettsii. DNA sequencing was performed on a portion of the 23S-5S IGS amplicons and the results were concordant with RLB assay results. We conclude that Rickettsia spp. are common in D. variabilis in North Carolina. Geographic patterns in the occurrence of Rickettsia-infected D. variabilis ticks across the counties sampled are discussed.
- Reproductive Manipulators in the Bark Beetle Pityogenes chalcographus (Coleoptera: Curculionidae)-The Role of Cardinium, Rickettsia, Spiroplasma, and Wolbachia. [Journal Article]
- JIJ Insect Sci 2018 May 01; 18(3)
- Heritable bacterial endosymbionts can alter the biology of numerous arthropods. They can influence the reproductive outcome of infected hosts, thus affecting the ecology and evolution of various arth...
Heritable bacterial endosymbionts can alter the biology of numerous arthropods. They can influence the reproductive outcome of infected hosts, thus affecting the ecology and evolution of various arthropod species. The spruce bark beetle Pityogenes chalcographus (L.) (Coleoptera: Curculionidae: Scolytinae) was reported to express partial, unidirectional crossing incompatibilities among certain European populations. Knowledge on the background of these findings is lacking; however, bacterial endosymbionts have been assumed to manipulate the reproduction of this beetle. Previous work reported low-density and low-frequency Wolbachia infections of P. chalcographus but found it unlikely that this infection results in reproductive alterations. The aim of this study was to test the hypothesis of an endosymbiont-driven incompatibility, other than Wolbachia, reflected by an infection pattern on a wide geographic scale. We performed a polymerase chain reaction (PCR) screening of 226 individuals from 18 European populations for the presence of the endosymbionts Cardinium, Rickettsia, and Spiroplasma, and additionally screened these individuals for Wolbachia. Positive PCR products were sequenced to characterize these bacteria. Our study shows a low prevalence of these four endosymbionts in P. chalcographus. We detected a yet undescribed Spiroplasma strain in a single individual from Greece. This is the first time that this endosymbiont has been found in a bark beetle. Further, Wolbachia was detected in three beetles from two Scandinavian populations and two new Wolbachia strains were described. None of the individuals analyzed were infected with Cardinium and Rickettsia. The low prevalence of bacteria found here does not support the hypothesis of an endosymbiont-driven reproductive incompatibility in P. chalcographus.
- A Concise Review of the Epidemiology and Diagnostics of Rickettsioses: Rickettsia and Orientia spp. [Journal Article]
- JCJ Clin Microbiol 2018 May 16
- Rickettsioses are globally distributed and caused by the family Rickettsiaceae, which comprise a diverse and expanding list. These include two genera: Rickettsia and Orientia Serology has been tradit...
Rickettsioses are globally distributed and caused by the family Rickettsiaceae, which comprise a diverse and expanding list. These include two genera: Rickettsia and Orientia Serology has been traditionally the main-stay of diagnosis, although this has been limited by cross-reactions among closely related members and diminished sensitivity/utility in the acute phase of illness. Other techniques such as nucleic acid amplification tests using blood specimens or tissue swabs/biopsies, sequencing and mass-spectrometry have emerged in recent years for both pathogen and vector identification. This paper provides a concise review of the rickettsioses and the traditional and newer technologies available for their diagnosis.
- Heterogeneity in skin manifestations of spotted fever group rickettsial infection in Australia. [Letter]
- AJAustralas J Dermatol 2018 May 16
- Dissemination of Orientia tsutsugamushi, a Causative Agent of Scrub Typhus, and Immunological Responses in the Humanized DRAGA Mouse. [Journal Article]
- FIFront Immunol 2018; 9:816
- Scrub typhus is caused by Orientia tsutsugamushi, an obligated intracellular bacterium that affects over one million people per year. Several mouse models have been used to study its pathogenesis, di...
Scrub typhus is caused by Orientia tsutsugamushi, an obligated intracellular bacterium that affects over one million people per year. Several mouse models have been used to study its pathogenesis, disease immunology, and for testing vaccine candidates. However, due to the intrinsic differences between the immune systems in mouse and human, these mouse models could not faithfully mimic the pathology and immunological responses developed by human patients, limiting their value in both basic and translational studies. In this study, we have tested for the first time, a new humanized mouse model through footpad inoculation of O. tsutsugamushi in DRAGA (HLA-A2.HLA-DR4.Rag1KO.IL2RγcKO.NOD) mice with their human immune system reconstituted by infusion of HLA-matched human hematopoietic stem cells from umbilical cord blood. Upon infection, Orientia disseminated into various organs of DRAGA mice resulted in lethality in a dose-dependent manner, while all C3H/HeJ mice infected by the same route survived. Tissue-specific lesions associated with inflammation and/or necroses were observed in multiple organs of infected DRAGA mice. Consistent with the intracellular nature of Orientia, strong Th1, but subdued Th2 responses were elicited as reflected by the human cytokine profiles in sera from infected mice. Interestingly, the percentage of both activated and regulatory (CD4+FOXP3+) human T cells were elevated in spleen tissues of infected mice. After immunization with irradiated whole cell Orientia, humanized DRAGA mice showed a significant activation of human T cells as evidenced by increased number of human CD4+ and CD8+ T cells. Specific human IgM and IgG antibodies were developed after repetitive immunization. The humanized DRAGA mouse model represents a new pre-clinical model for studying Orientia-human interactions and also for testing vaccines and novel therapeutics for scrub typhus.
New Search Next
- Case 14-2018: A 68-Year-Old Woman with a Rash, Hyponatremia, and Uveitis. [Case Reports]
- NEJMN Engl J Med 2018 May 10; 378(19):1825-1833