Short report: Detection of borrelia (relapsing fever) in rural Ethiopia by means of the quantitative buffy coat technique. (17/122)

The diagnosis of louse-borne relapsing fever is commonly made on the basis of the detection of Borrelia spirochetes on Giemsa-stained thin blood films. In the present study, we used acridine orange-coated quantitative buffy coat (QBC) tubes, centrifugation, and fluorescence microscopy to detect Borrelia. Between July and August 1998, we used the QBC technique to diagnose 7 patients with borreliosis who visited a rural clinic in southwest Ethiopia. In laboratory studies that used Borrelia burgdorferi as a model, we detected spirochetes at concentrations as low as 10 organisms/mm3, whereas the number of positive readings assessed by means of stained blood films fell significantly at dilutions below 3,263 organisms/mm3. The greater sensitivity of the QBC technique is important in areas where Borrelia is endemic, as in the Horn of Africa. It may also prove useful in evaluating relapsing fevers in travelers.  (+info)

Cutting edge: the spirochetemia of murine relapsing fever is cleared by complement-independent bactericidal antibodies. (18/122)

Abs are the major effectors of host defense against infections with BORRELIA: Bactericidal murine mAbs and their Fabs destroy B. burgdorferi, the agent of Lyme disease, and relapsing fever Borrelia in the absence of complement. These in vitro observations led to the expansion of a search for functionally similar Abs in vivo. In this study, we demonstrate that functionally unique IgM Abs develop in vivo and are responsible for the elimination of spirochetemia in murine models of relapsing fever, without the assistance of complement. Mice deficient in the fifth or third component of complement can clear the spirochetemia, whereas B cell-deficient mice cannot. The B cell-deficient mice developed spirochetemia that was an order of magnitude higher and persisted for a longer period of time in comparison to the wild-type mice. Additionally, B cell-deficient mice passively immunized with immune IgM and with immune serum were protected from challenge.  (+info)

Use of a sentinel host system to study the questing behavior of Ixodes spinipalpis and its role in the transmission of Borrelia bissettii, human granulocytic ehrlichiosis, and Babesia microti. (19/122)

Ixodes spinipalpis maintains Borrelia bissettii spirochetes in Colorado in a cycle involving wood rats and deer mice. This tick has been described as nidicolous, remaining either attached to its rodent hosts or in the rodent nest. Nidicolous ticks pose little risk of pathogen transmission to humans if they do not actively quest for hosts. To investigate the questing potential of I. spinipalpis, sentinel mice were placed in an area where I. spinipalpis had been commonly found on wood rats and deer mice. Concurrently, wild rodent populations were trapped and analyzed for Lyme disease spirochetes, the agent of human granulocytic ehrlichiosis (aoHGE), and Babesia microti. A total of 122 I. spinipalpis larvae and 10 nymphs were found on 19% of 244 sentinel mice. In addition, 4 sentinel mice became infested with Malaraeus telchinus or Orchopeas neotomae fleas. Questing I. spinipalpis were positively associated with woody shrubs and negatively associated with sunny and grassy areas. Four sentinel mice became infected with aoHGE after having been fed upon only by I. spinipalpis larvae. One sentinel mouse became infected with B. bissettii after having an I. spinipalpis nymph feed on it, and one sentinel mouse became coinfected with aoHGE and B. bissettii after it was fed upon by a single I. spinipalpis nymph. These sentinel mouse conversions suggest the possibility that the aoHGE is transovarially transmitted by I. spinipalpis, and that I. spinipalpis is capable of simultaneously transmitting B. bissettii and the aoHGE. The findings that I. spinipalpis quest away from rodent nests and will attach to and infect sentinel mice may be of public health importance. It suggests the potential transmission of the agents of human granulocytic ehrlichiosis and Lyme disease to other hosts by I. spinipalpis, in regions of the western United States where Ixodes pacificus is not found.  (+info)

Preliminary studies on the relationship between Ixodes ricinus activity and tick-borne infection among occupationally-exposed inhabitants of eastern Poland. (20/122)

Relative density (activity) of the tick Ixodes ricinus was determined in five districts of the Lublin region (eastern Poland) by vegetation flagging. Tick activity values were compared to the determined by ELISA tests seroprevalence to tick-borne encephalitis virus (TBEV) and Borrelia burgdorferi in forestry workers and farmers from the same areas. A significant correlation between tick activity and seroprevalence to both TBEV and B. burgdorferi antigen was found in farmers and in the total examined population.  (+info)

Toll-like receptor 2 is required for innate, but not acquired, host defense to Borrelia burgdorferi. (21/122)

Borrelia burgdorferi lipoproteins activate inflammatory cells through Toll-like receptor 2 (TLR2), suggesting that TLR2 could play a pivotal role in the host response to B. burgdorferi. TLR2 does play a critical role in host defense, as infected TLR2(-/-) mice harbored up to 100-fold more spirochetes in tissues than did TLR2(+/+) littermates. Spirochetes persisted at extremely elevated levels in TLR2-deficient mice for at least 8 wk following infection. Infected TLR2(-/-) mice developed normal Borrelia-specific Ab responses, as measured by quantity of Borrelia-specific Ig isotypes, the kinetics of class switching to IgG, and the complexity of the Ags recognized. These findings indicate that the failure to control spirochete levels in tissues is not due to an impaired acquired immune response. While macrophages from TLR2(-/-) mice were not responsive to lipoproteins, they did respond to nonlipoprotein components of sonicated spirochetes. These TLR2-independent responses could play a role during the inflammatory response to B. burgdorferi, as infected TLR2(-/-) mice developed greater ankle swelling than wild-type littermates. Thus, while TLR2-dependent signaling pathways play a major role in the innate host defense to B. burgdorferi, both inflammatory responses and the development of the acquired humoral response can occur in the absence of TLR2.  (+info)

A portuguese isolate of Borrelia lusitaniae induces disease in C3H/HeN mice. (22/122)

A low-passage, Portuguese isolate of Borrelia lusitaniae, strain PotiB2, was inoculated into C3H/HeN mice and disease was monitored by histopathology at 8 weeks after spirochaete challenge. Ear, heart, bladder, femoro-tibial joint, brain and spinal cord were examined. B. lusitaniae strain PotiB2 (6 of 10 mice) and B. burgdorferi sensu stricto strain N40 (9 of 10 mice) induced similar lesions in the bladder of infected mice characterised as a multifocal, lymphoid, interstitial cystitis. Moreover, both B. lusitaniae PotiB2 and B. burdorferi N40 induced lesions in the heart of infected mice. The lesions induced by B. lusitaniae PotiB2 (2 of 10 mice) were characterised as a severe, necrotising endarteritis of the aorta, with a minimal, mixed inflammatory infiltrate (neutrophils, macrophages and lymphoid cells) extending into the adjacent myocardium. In contrast, B. burgdorferi N40 induced a periarteritis of the pulmonary artery (7 of 10 mice), with no involvement of the endothelium and more extensive inflammation and subsequent necrosis of the adjacent myocardium. This infiltrate was composed entirely of mononuclear cells, predominantly mature lymphocytes and plasma cells. No lesions were noted in the joints or central nervous system with inoculation of strains N40 or PotiB2, and co-inoculation of either strain with Ixodes ricinus salivary gland lysate did not affect the resulting pathology. Serology, examined 8 weeks after inoculation, indicated a different reactivity in mice infected with B. lusitaniae PotiB2 compared with B. burgdorferi N40. Immunoblot analysis demonstrated that mice with lesions resulting from infection with B. lusitaniae PotiB2 reacted only to the flagellin protein (41 kDa) or to flagellin and OspC, whereas mice infected with B. burgdorferi N40 reacted with multiple high and low mol. wt proteins, including flagellin, p93, p39, OspA, OspB and OspC. These results indicate that B. lusitaniae PotiB2 induced pathology similar to B. burgdorferi N40 when inoculated into susceptible mice. Moreover, these results establish the first animal model of disease with B. lusitaniae. This mouse model can be used to characterise the immunopathogenesis of B. lusitaniae infection and to delineate the proteins responsible for disease induction in susceptible mice.  (+info)

Genetic diversity of the outer surface protein C gene of southern Borrelia isolates and its possible epidemiological, clinical, and pathogenetic implications. (23/122)

The ospC genes of 20 southern Borrelia strains were sequenced. The strains consisted of B. burgdorferi sensu stricto, B. andersonii, B. bissettii, one undescribed genospecies, MI-8, and one probably new Borrelia species, TXW-1. A high degree of similarity exists between B. burgdorferi sensu stricto and B. bissettii and between B. bissettii and B. andersonii. Lateral transfers of the ospC gene probably occurred between B. burgdorferi sensu stricto and B. bissettii and between B. bissettii and B. andersonii. Internal gene recombination appears to occur among them. The highest degree of genetic diversity among them was observed in the two variable domains (V1 and V2), semivariable domain (SV), and the species-specific epitopes (between amino acids 28 and 31). Differences in ospC sequences among southern strains reflect diversity at the strain and genospecies levels. MI-8, which was recognized as an undescribed genospecies in our previous reports, remains distinguishable in our current analysis of ospC genes and is distinct from B. burgdorferi sensu stricto. Interestingly, another undescribed southern isolate, TXW-1, was not amplified under various PCR conditions. Compared to European B. burgdorferi sensu stricto strains, American B. burgdorferi sensu stricto strains show greater genetic heterogeneity. Southern B. burgdorferi sensu stricto, B. andersonii, and B. bissettii isolates were intermixed with each other in the phylogenetic trees. In the derived trees in our work, at least one southeastern strain of B. burgdorferi, MI-2, most closely aligns with a so-called invasive cluster that possesses many proven human-invasive strains. Transmission experiments show that MI-2 and the strains in this group of southern spirochetes are able to infect mice and hamsters and that the typical vector of Lyme disease, Ixodes scapularis, can acquire the spirochetes from infected mammals. Currently, strain MI-2 appears to be the only southern isolate among the 20 we analyzed that clusters with an OspC invasive group and thus might be invasive for humans.  (+info)

In vitro culture of Borrelia garinii results in loss of flagella and decreased invasiveness. (24/122)

A virulent, low-passage culture of a tick-derived strain of Borrelia garinii was subjected to serial in vitro passages, from which inoculations were made into C3H/HeN mice. A full display of pathogenicity was observed through passage 4, as measured by cultures of ear punch biopsy samples and internal organs and determination of tibiotarsal joint swelling. Decreased dissemination through skin and infection of internal organs were observed beginning at passage 6. These losses correlated with both the selection of clones harboring 21% less flagella than the parent strain, as seen by electron microscopy, and loss of the motility of the higher passages, as demonstrated by a swarm assay. However, during the chronic phase (3 months after infection), spirochetes were cultured from the bladder and kidney of a mouse inoculated with passage 12. The kidney isolate had the same number of flagella and motility as the original low-passage isolate. Although we can't exclude the possibility that other subtle variations may be arising given the uncloned nature of the isolate, we have found a strong association between loss of flagella and decreased invasiveness. Arthritogenicity progressively decreased with passages, so that only 12.5% of chronically infected mice inoculated with passage 29 still presented with joint swelling, concurrent with a decrease in the staining intensity in a Southern blot with a vlsE-based probe. These results suggest a multifactorial model in which the number of flagella drives the invasiveness of this agent, while plasmid-associated factors are responsible for triggering arthritogenicity.  (+info)