scholarly journals TrackingBorrelia afzeliifrom infectedIxodes ricinusnymphs to mice suggests a direct ‘gut-to-mouth’ route of Lyme disease transmission

2018 ◽  
Author(s):  
Tereza Pospisilova ◽  
Veronika Urbanova ◽  
Ondrej Hes ◽  
Petr Kopacek ◽  
Ondrej Hajdusek ◽  
...  
Keyword(s):  
Salivary Glands ◽  
Lyme Borreliosis ◽  
Disease Transmission ◽  
Ixodes Scapularis ◽  
Surface Protein ◽  
Gut Contents ◽  
Tick Saliva ◽  
Borrelia Afzelii ◽  
Transmission Cycle ◽  
Main Requirement

AbstractQuantitative tracking ofBorrelia afzeliihas shown that its transmission cycle differs from the salivary route ofB. burgdorferitransmission byIxodes scapularis.Borrelia afzeliiare abundant in the guts of unfedIxodes ricinusnymphs and their numbers continuously decrease during feeding. In contrast, spirochetes are not present in the salivary glands.Borrelia afzeliitransmission starts during the early stages of feeding, spirochetes could be detected in murine skin within 1 day of tick attachment. Tick saliva is not essential forB. afzeliiinfectivity, the main requirement for successful host colonization being a change in outer surface protein expression that occurs in the tick gut during feeding. Spirochetes in vertebrate mode are able to survive within the host even if the tick is not present. On the basis of our data we propose that a direct ‘gut-to-mouth’ route of infection appears to be the main route ofB. afzeliitransmission.ImportanceLyme borreliosis is the most common vector-borne disease in the USA and Europe. The disease is caused by theBorreliaspirochetes and is transmitted throughIxodesticks. A better understanding of howBorreliaspirochetes are transmitted is crucial for development of efficient vaccines for preventing Lyme borreliosis. Here we present that the transmission of EuropeanB. afzeliispirochetes byI. ricinusticks significantly differs from the model transmission cycle described for AmericanB. burgdorferi/I. scapularis. We suggest thatB. afzeliiis not transmitted via salivary glands but most likely through the ‘midgut to mouthpart’ route. We further demonstrate that tick saliva is not important forB. afzeliitransmission and infectivity. Therefore, we support early studies by Willy Burgdorfer, who proposed thatBorreliatransmission occurs by regurgitation of infected gut contents. Our findings collectively point to theBorrelia-tick midgut interface as the correct target in our endeavours to combat Lyme borreliosis.

scholarly journals Tracking ofBorrelia afzeliiTransmission from InfectedIxodes ricinusNymphs to Mice

2019 ◽  
Vol 87 (6) ◽  
Author(s):  
Tereza Pospisilova ◽  
Veronika Urbanova ◽  
Ondrej Hes ◽  
Petr Kopacek ◽  
Ondrej Hajdusek ◽  
...  
Keyword(s):  
Ixodes Scapularis ◽  
Surface Proteins ◽  
Tick Feeding ◽  
Tick Saliva ◽  
Content Type ◽  
Borrelia Afzelii ◽  
Transmission Cycle ◽  
Transmission Mechanisms ◽  
Outer Surface Proteins ◽  
Tick Attachment

ABSTRACTQuantitative and microscopic tracking ofBorrelia afzeliitransmission from infectedIxodes ricinusnymphs has shown a transmission cycle different from that ofBorrelia burgdorferiandIxodes scapularis.Borrelia afzeliiorganisms are abundant in the guts of unfedI. ricinusnymphs, and their numbers continuously decrease during feeding.Borrelia afzeliispirochetes are present in murine skin within 1 day of tick attachment. In contrast, spirochetes were not detectable in salivary glands at any stage of tick feeding. Further experiments demonstrated that tick saliva is not essential forB. afzeliiinfectivity, the most important requirement for successful host colonization being a change in expression of outer surface proteins that occurs in the tick gut during feeding. Spirochetes in vertebrate mode are then able to survive within the host even in the absence of tick saliva. Taken together, our data suggest that the tick gut is the decisive organ that determines the competence ofI. ricinusto vectorB. afzelii. We discuss possible transmission mechanisms ofB. afzeliispirochetes that should be further tested in order to design effective preventive and therapeutic strategies against Lyme disease.

scholarly journals Methods for Estimating Gene Frequencies and Detecting Selection in Bacterial Populations

Genetics ◽  
2000 ◽  
Vol 155 (2) ◽  
pp. 499-508 ◽  
Author(s):  
Bruce Rannala ◽  
Wei-Gang Qiu ◽  
Daniel E Dykhuizen
Keyword(s):  
Ixodes Scapularis ◽  
Balancing Selection ◽  
Surface Protein ◽  
Allele Frequencies ◽  
Gene Frequencies ◽  
Bacterial Populations ◽  
Polymerase Chain ◽  
Host Infection ◽  
Infinite Alleles Model

Abstract Recent breakthroughs in molecular technology, most significantly the polymerase chain reaction (PCR) and in situ hybridization, have allowed the detection of genetic variation in bacterial communities without prior cultivation. These methods often produce data in the form of the presence or absence of alleles or genotypes, however, rather than counts of alleles. Using relative allele frequencies from presence-absence data as estimates of population allele frequencies tends to underestimate the frequencies of common alleles and overestimate those of rare ones, potentially biasing the results of a test of neutrality in favor of balancing selection. In this study, a maximum-likelihood estimator (MLE) of bacterial allele frequencies designed for use with presence-absence data is derived using an explicit stochastic model of the host infection (or bacterial sampling) process. The performance of the MLE is evaluated using computer simulation and a method is presented for evaluating the fit of estimated allele frequencies to the neutral infinite alleles model (IAM). The methods are applied to estimate allele frequencies at two outer surface protein loci (ospA and ospC) of the Lyme disease spirochete, Borrelia burgdorferi, infecting local populations of deer ticks (Ixodes scapularis) and to test the fit to a neutral IAM.

Association of Borrelia afzelii with rodents in Europe

Parasitology ◽  
2003 ◽  
Vol 126 (1) ◽  
pp. 11-20 ◽  
Author(s):  
K. HANINCOVÁ ◽  
S. M. SCHÄFER ◽  
S. ETTI ◽  
H.-S. SEWELL ◽  
V. TARAGELOVÁ ◽  
...  
Keyword(s):  
Borrelia Burgdorferi ◽  
Lyme Borreliosis ◽  
Tick Infestation ◽  
Zoonotic Transmission ◽  
Host Association ◽  
Borrelia Afzelii ◽  
Hard Ticks ◽  
Bank Voles ◽  
Endemic Focus ◽  
Questing Ticks

Borrelia burgdorferi sensu lato (s.l.) is maintained in nature by complex zoonotic transmission cycles, involving a large variety of vertebrates as hosts and hard ticks of the genus Ixodes as vectors. Recent studies suggest that the genospecies of B. burgdorferi s.l. and sometimes their subtypes are propagated by different spectra of hosts, mainly birds and rodents. In order to test the concept of host-association, we analysed the relationships between Borrelia genospecies, rodent hosts and I. ricinus ticks in an endemic focus of Lyme borreliosis in western Slovakia. Rodents and questing ticks were collected at a forested lowland locality near Bratislava. Tick infestation levels on rodents were determined, and spirochaete infections in ticks and in ear punch biopsies were analysed by PCR followed by genotyping. Mice were more heavily infested with ticks than bank voles, and a higher proportion of mice was infected with spirochaetes than voles. However, the infectivity of voles was much higher than that of mice. The vast majority of infections detected in the skin and in ticks feeding on the rodents represented B. afzelii. In contrast, more than half of all infections in questing ticks collected in the same region of Slovakia were identified as B. valaisiana and B. garinii. In conclusion, whilst the study reveals that mice and voles play different quantitative roles in the ecology of Lyme borreliosis, it demonstrates that B. afzelii is specifically maintained by European rodents, validating the concept of host-association of B. burgdorferi s.l.

scholarly journals Ixodes scapularis Tick Saliva Proteins Sequentially Secreted Every 24 h during Blood Feeding

2016 ◽  
Vol 10 (1) ◽  
pp. e0004323 ◽  
Author(s):  
Tae Kwon Kim ◽  
Lucas Tirloni ◽  
Antônio F. M. Pinto ◽  
James Moresco ◽  
John R. Yates ◽  
...  
Keyword(s):  
Ixodes Scapularis ◽  
Blood Feeding ◽  
Tick Saliva

scholarly journals SSP3 Is a Novel Plasmodium yoelii Sporozoite Surface Protein with a Role in Gliding Motility

2014 ◽  
Vol 82 (11) ◽  
pp. 4643-4653 ◽  
Author(s):  
Anke Harupa ◽  
Brandon K. Sack ◽  
Viswanathan Lakshmanan ◽  
Nadia Arang ◽  
Alyse N. Douglass ◽  
...  
Keyword(s):  
Salivary Glands ◽  
Biological Activities ◽  
Surface Protein ◽  
Plasmodium Yoelii ◽  
Gliding Motility ◽  
Surface Proteins ◽  
Type I ◽  
Content Type ◽  
Mosquito Midgut

ABSTRACTPlasmodiumsporozoites develop within oocysts in the mosquito midgut wall and then migrate to the salivary glands. After transmission, they embark on a complex journey to the mammalian liver, where they infect hepatocytes. Proteins on the sporozoite surface likely mediate multiple steps of this journey, yet only a few sporozoite surface proteins have been described. Here, we characterize a novel, conserved sporozoite surface protein (SSP3) in the rodent malaria parasitePlasmodium yoelii. SSP3 is a putative type I transmembrane protein unique toPlasmodium. By using epitope tagging and SSP3-specific antibodies in conjunction with immunofluorescence microscopy, we showed that SSP3 is expressed in mosquito midgut oocyst sporozoites, exhibiting an intracellular localization. In sporozoites derived from the mosquito salivary glands, however, SSP3 localized predominantly to the sporozoite surface as determined by immunoelectron microscopy. However, the ectodomain of SSP3 appeared to be inaccessible to antibodies in nonpermeabilized salivary gland sporozoites. Antibody-induced shedding of the major surface protein circumsporozoite protein (CSP) exposed the SSP3 ectodomain to antibodies in some sporozoites. Targeted deletion ofSSP3adversely affectedin vitrosporozoite gliding motility, which, surprisingly, impacted neither their cell traversal capacity, host cell invasionin vitro, nor infectivityin vivo. Together, these data reveal a previously unappreciated complexity of thePlasmodiumsporozoite surface proteome and the roles of surface proteins in distinct biological activities of sporozoites.

scholarly journals Antigenic Variation of Anaplasma Marginale: Major Surface Protein 2 Diversity during Cyclic Transmission between Ticks and Cattle

2001 ◽  
Vol 69 (5) ◽  
pp. 3057-3066 ◽  
Author(s):  
A. F. Barbet ◽  
Jooyoung Yi ◽  
Anna Lundgren ◽  
B. R. McEwen ◽  
E. F. Blouin ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Salivary Glands ◽  
Antigenic Variation ◽  
Hypervariable Region ◽  
Surface Protein ◽  
Genomic Expression ◽  
Major Surface Protein ◽  
Expression Site ◽  
Major Surface ◽  
Tick Salivary Glands

ABSTRACT The rickettsial pathogen Anaplasma marginale expresses a variable immunodominant outer membrane protein, major surface protein 2 (MSP2), involved in antigenic variation and long-term persistence of the organism in carrier animals. MSP2 contains a central hypervariable region of about 100 amino acids that encodes immunogenic B-cell epitopes that induce variant-specific antibodies during infection. Previously, we have shown that MSP2 is encoded on a polycistronic mRNA transcript in erythrocyte stages of A. marginale and defined the structure of the genomic expression site for this transcript. In this study, we show that the same expression site is utilized in stages of A. marginale infecting tick salivary glands. We also analyzed the variability of this genomic expression site in Oklahoma strain A. marginale transmitted from in vitro cultures to cattle and between cattle and ticks. The structure of the expression site and flanking regions was conserved except for sequence that encoded the MSP2 hypervariable region. At least three different MSP2 variants were encoded in each A. marginalepopulation. The major sequence variants did not change on passage ofA. marginale between culture, acute erythrocyte stage infections, and tick salivary glands but did change during persistent infections of cattle. The variant types found in tick salivary glands most closely resembled those present in bovine blood at the time of acquisition of infection, whether infection was acquired from an acute or from a persistent rickettsemia. These variations in structure of an expression site for a major, immunoprotective outer membrane protein have important implications for vaccine development and for obtaining an improved understanding of the mechanisms of persistence of ehrlichial infections in humans, domestic animals, and reservoir hosts.

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