Identification and characterization of a Relish-type NF-κB, DvRelish, in in response to infection.

Ixodid ticks serve as hosts and transmission vectors for several obligate intracellular bacteria, including members of the spotted fever group (SFG) of . Although ticks generate an immune response to bacterial insults, many of the signaling molecules associated with the response and how they may contribute to vector competence for are undefined. In this study, we isolated a full-length transcript from , which encoded a Relish-type NF-κB.

A conserved interaction between the effector Sca4 and host clathrin suggests additional contributions for Sca4 during rickettsial infection.

Intracellular bacterial pathogens deploy secreted effector proteins that manipulate diverse host machinery and pathways to promote infection. Although many effectors carry out a single function or interaction, there are a growing number of secreted effectors capable of interacting with multiple host factors. However, few effectors secreted by arthropod-borne obligate intracellular species have been linked to multiple host targets.

A conserved interaction between the effector Sca4 and host endocytic machinery suggests additional roles for Sca4 during rickettsial infection.

Intracellular bacterial pathogens deploy secreted effector proteins that manipulate diverse host machinery and pathways to promote infection. Although many effectors carry out a single specific function or interaction, there are a growing number of secreted pathogen effectors capable of interacting with multiple host factors. However, few effectors secreted by obligate intracellular species have been linked to multiple host targets.

Salivary glands of the cat flea, : Dissection and microscopy guide.

Fleas are morphologically unique ectoparasites that are hardly mistaken for any other insect. Most flea species that feed on humans and their companion animals, including the cat flea (), have medical and veterinary importance. Besides facilitating blood acquisition, salivary biomolecules can modulate pathogen transmission.

Cat Flea Coinfection with and .

Flea-borne rickettsioses, collectively referred to as a term for etiological agents , , and RFLOs (-like organisms), has become a public health concern around the world, specifically in the United States. Due to a shared arthropod vector (the cat flea) and clinical signs, discriminating between species has proven difficult. While the effects of microbial coinfections in the vector can result in antagonistic or synergistic interrelationships, subsequently altering potential human exposure and disease, the impact of bacterial interactions within flea populations remains poorly defined.

Critical roles of outer membrane protein B (OmpB) in the tick host.

is a pathogen of public health concern and transmitted by the Gulf Coast tick, . Rickettsiae are obligate intracellular bacteria that enter and replicate in diverse host cells. Rickettsial outer membrane protein B (OmpB) functions in bacterial adhesion, invasion, and avoidance of cell-autonomous immunity in mammalian cell infection, but the function of OmpB in arthropod infection is unknown.

ATP-sensitive inward rectifier potassium channels regulate secretion of pro-feeding salivary proteins in the lone star tick (Amblyomma americanum).

Understanding the physiological and molecular regulation of tick feeding is necessary for developing intervention strategies to curb disease transmission by ticks. Pharmacological activation of ATP-gated inward rectifier potassium (K) channels reduced fluid secretion from isolated salivary gland and blood feeding in the lone star tick, Amblyomma americanum, yet the temporal expression pattern of K channel proteins remained unknown. K channels were highly expressed in type II and III acini in off-host stage and early feeding phase ticks, yet expression was reduced in later stages of feeding.

Revisiting the sialome of the cat flea Ctenocephalides felis.

The hematophagous behaviour emerged independently in several instances during arthropod evolution. Survey of salivary gland and saliva composition and its pharmacological activity led to the conclusion that blood-feeding arthropods evolved a distinct salivary mixture that can interfere with host defensive response, thus facilitating blood acquisition and pathogen transmission. The cat flea, Ctenocephalides felis, is the major vector of several pathogens, including Rickettsia typhi, Rickettsia felis and Bartonella spp.

Transposon mutagenesis of Rickettsia felis sca1 confers a distinct phenotype during flea infection.

Since its recognition in 1994 as the causative agent of human flea-borne spotted fever, Rickettsia felis, has been detected worldwide in over 40 different arthropod species. The cat flea, Ctenocephalides felis, is a well-described biological vector of R. felis.

The role of cofeeding arthropods in the transmission of Rickettsia felis.

Rickettsia felis is an emerging etiological agent of rickettsioses worldwide. The cosmopolitan cat flea (Ctenocephalides felis) is the primary vector of R. felis, but R.

Infection in Ticks and Tick-Derived Cells.

Leprosy is a zoonosis in the southern United States involving humans and wild armadillos. The majority of patients presenting with zoonotic strains of note extensive outdoor activity but only rarely report any history of direct contact with wild armadillos. Whether is transmitted to new vertebrate hosts through the environment independently or with the aid of other organisms, e.

Unpacking the intricacies of Rickettsia-vector interactions.

Although Rickettsia species are molecularly detected among a wide range of arthropods, vector competence becomes an imperative aspect of understanding the ecoepidemiology of these vector-borne diseases. The synergy between vector homeostasis and rickettsial invasion, replication, and release initiated within hours (insects) and days (ticks) permits successful transmission of rickettsiae. Uncovering the molecular interplay between rickettsiae and their vectors necessitates examining the multifaceted nature of rickettsial virulence and vector infection tolerance.

Dynamic gene expression in salivary glands of the cat flea during Rickettsia felis infection.

The cat flea, Ctenocephalides felis, is an arthropod vector capable of transmitting several human pathogens including Rickettsia species. Earlier studies identified Rickettsia felis in the salivary glands of the cat flea and transmission of rickettsiae during arthropod feeding. The saliva of hematophagous insects contains multiple biomolecules with anticlotting, vasodilatory and immunomodulatory activities.

The complete mitochondrial genome of the cat flea, .

The cat flea, , is widely recognized as a global veterinary pest and a vector of pathogenic bacteria. We recently reported on the . nuclear genome, which is characterized by over 38% protein coding gene duplication, extensive tRNA gene family expansion, and remarkable gene copy number variation (CNV) between individual fleas.

Evolution of mutualism and reproductive parasitism: insight from two novel strains that co-infect cat fleas.

Wolbachiae are obligate intracellular bacteria that infect arthropods and certain nematodes. Usually maternally inherited, they may provision nutrients to (mutualism) or alter sexual biology of (reproductive parasitism) their invertebrate hosts. We report the assembly of closed genomes for two novel wolbachiae, CfeT and CfeJ, found co-infecting cat fleas () of the Elward Laboratory colony (Soquel, CA, USA).

Comparative Analysis of Infection by Sheila Smith and Taiaçu Strains in a Murine Model.

Rocky Mountain spotted fever (RMSF) is a life-threatening tick-borne disease caused by , which is widely distributed throughout the Americas. Over 4000 cases of RMSF are recorded annually in the United States, while only around 100 cases are reported in Brazil. Conversely, while case fatality rates in the United States oscillate around 5%, in Brazil they can surpass 70%, suggesting that differences in tick vectoring capacity, population sensitivity, and/or variability in virulence of the rickettsial strains may exist.

A chromosome-level assembly of the cat flea genome uncovers rampant gene duplication and genome size plasticity.

Background: Fleas (Insecta: Siphonaptera) are small flightless parasites of birds and mammals; their blood-feeding can transmit many serious pathogens (i.e., the etiological agents of bubonic plague, endemic and murine typhus).

A non-coding RNA controls transcription of a gene encoding a DNA binding protein that modulates biofilm development in Bartonella henselae.

Bartonella henselae (Bh) is a Gram-negative zoonotic bacterium that can grow as large aggregates and form biofilms in vitro dependent upon the adhesin BadA. Previously, we reported that the Houston-1 strain of Bh has a family of nine small, highly-expressed intergenic transcripts called Bartonellaregulatory transcripts, Brt1-9. Each of the Brts bears a stem and loop structure on the 3' end followed by a gene encoding a DNA binding protein called the Transcriptional regulatory proteins, Trp1-9.

Correlation between fecal egg count, presence of Strongylus vulgaris, and body score of feral horses on Fort Polk, Louisiana.

Approximately 700 feral horses, dubbed "trespass horses" by the United States Army, occupy Fort Polk, Louisiana and the surrounding Kisatchie National Forest. These horses are considered a nuisance and hazard, and the military is seeking to remove the horses via adoption. The aim of this research was to evaluate the fecal egg count (FEC), body condition score (BCS), and the presence of Strongylus vulgaris within this previously unstudied horse population prior to removal.

Inward rectifier potassium (Kir) channels mediate salivary gland function and blood feeding in the lone star tick, Amblyomma americanum.

Background: Tick feeding causes extreme morbidity and mortality to humans through transmission of pathogens and causes severe economic losses to the agricultural industry by reducing livestock yield. Salivary gland secretions are essential for tick feeding and thus, reducing or preventing saliva secretions into the vertebrate host is likely to reduce feeding and hinder pathogen life cycles. Unfortunately, the membrane physiology of tick salivary glands is underexplored and this gap in knowledge limits the development of novel therapeutics for inducing cessation of tick feeding.

Spotted Fever Group Infection and Transmission Dynamics in .

Tick vectors are capable of transmitting several rickettsial species to vertebrate hosts, resulting in various levels of disease. Studies have demonstrated the transmissibility of both rickettsial pathogens and novel species or strains with unknown pathogenicity to vertebrate hosts during tick blood meal acquisition; however, the quantitative nature of transmission remains unknown. We tested the hypothesis that if infection severity is a function of the rickettsial load delivered during tick transmission, then a more virulent spotted fever group (SFG) species is transmitted at higher levels during tick feeding.

Rickettsia felis: A Review of Transmission Mechanisms of an Emerging Pathogen.

is an emerging pathogen of the transitional group of species and an important cause of febrile illness in Africa. Since the organism's original discovery in the early 1990s, much research has been directed towards elucidating transmission mechanisms within the primary host and reservoir, the cat flea (). Several mechanisms for vertical and horizontal transmission within this vector have been thoroughly described, as well as transmission to other arthropod vectors, including other species of fleas.

A Tangled Web: Origins of Reproductive Parasitism.

While typically a flea parasite and opportunistic human pathogen, the presence of Rickettsia felis (strain LSU-Lb) in the non-blood-feeding, parthenogenetically reproducing booklouse, Liposcelis bostrychophila, provides a system to ascertain factors governing not only host transitions but also obligate reproductive parasitism (RP). Analysis of plasmid pLbAR, unique to R. felis str.

Role of Sca2 and RickA in the Dissemination of Rickettsia parkeri in Amblyomma maculatum.

The Gram-negative obligate intracellular bacterium is an emerging tick-borne human pathogen. Recently, Sca2 and RickA have been implicated in adherence and actin-based motility in vertebrate host cell infection models; however, the rickettsia-derived factors essential to tick infection are unknown. Using mutants lacking functional Sca2 or RickA to compare actin polymerization, replication, and cell-to-cell spread , similar phenotypes in tick and mammalian cells were observed.