@article{yang_ladouceur_baumgartner_marr_karounos_robertson_whitehurst_miller_birkenheuer_2023, title={A practical protocol to prepare paraffin-embedded whole tick histology sections}, volume={14}, ISSN={["1877-9603"]}, url={https://doi.org/10.1016/j.ttbdis.2023.102162}, DOI={10.1016/j.ttbdis.2023.102162}, abstractNote={Ticks are important ectoparasites that are capable of transmitting multiple classes of pathogens and are currently linked with many emerging tick-borne diseases worldwide. With increasing occurrences of tick-borne diseases in both humans and veterinary species, there is a continuous need to further our understanding of ticks and the pathogens they transmit. Whole tick histology provides a full scope of the tick internal anatomy, allowing researchers to examine multiple organs of interest in a single section. This is in contrast to other techniques that are more commonly utilized in tick-borne disease research, such as electron microscopy and light microscopy of individual organs. There is a lack of literature describing a practical technique to process whole tick histologic sections. Therefore, the current study aims to provide researchers with a workable protocol to prepare high quality paraffin-embedded whole tick histology sections. Amblyomma americanum adults were used as an example species for this study. After a series of pilot experiments using a combination of various fixatives, softening agents and processing techniques, we elected to compare two common fixatives, 10% neutral-buffered formalin (NBF) and Bouin's solution for whole ticks. Equal numbers of A. americanum unfed adults (n = 10/fixative) were processed identically and their whole tick histology coronal sections were individually scored. Higher scores were assigned to whole tick sections that contained more internal organs that are crucial for tick-borne disease research (e.g. salivary glands and midgut), high integrity of tissues and exoskeleton on the section, and good fixation and staining quality of the tissues. The mean total scores for Bouin's-fixed ticks were significantly higher compared to NBF-fixed ticks (p = 0.001). To further assess our preferred technique, we also demonstrated the feasibility of producing high quality whole tick sections for three other common tick species of medical importance (Rhipicephalus sanguineus, Ixodes scapularis, and Dermacentor variabilis) using Bouin's solution. While this technique may require further optimization for other tick species, we described a feasible protocol that uses commonly available tools, reagents and standard histologic equipment. This should allow any investigator to easily make adjustments to this protocol as needed based on their experimental goals.}, number={4}, journal={TICKS AND TICK-BORNE DISEASES}, author={Yang, Tzushan S. and LaDouceur, Elise E. B. and Baumgartner, Wes A. and Marr, Henry S. and Karounos, Michael and Robertson, James and Whitehurst, Nathan and Miller, Laura S. and Birkenheuer, Adam J.}, year={2023}, month={Jul} }
 @article{yang_reichard_thomas_miller_marr_karounos_bell_birkenheuer_2023, title={Cytauxzoon felis in salivary glands of Amblyomma americanum}, volume={14}, ISSN={["1877-9603"]}, DOI={10.1016/j.ttbdis.2022.102056}, abstractNote={Cytauxzoon felis is a tick-borne piroplasmid hemoparasite that causes life-threatening disease in cats. Despite the critical role that ticks play in pathogen transmission, our knowledge regarding the C. felis life cycle remains limited to the feline hosts. Specific life stages of C. felis within the tick host have never been visualized microscopically and previous investigations have been limited to molecular detection by polymerase chain reaction (PCR). Sporozoites are the infectious stage of piroplasmids that are transmitted by ticks. In other tick-borne piroplasmids, sporozoite-based vaccines play a key role in disease prevention and management. We believe sporozoites have similar potential for cytauxzoonosis. Therefore, the objective of this study was to use different molecular and microscopic techniques to detect and evaluate C. felis sporozoites in tick salivary glands (SG). A total of 140 Amblyomma americanum adults that were fed on C. felis-infected cats as nymphs were included for this study. Specifically, dissected SGs were quartered and subjected to C. felis RT-PCR, RNAscope® in situ hybridization (ISH), histology, direct azure staining, and transmission electron microscopy (TEM). Cytauxzoon felis RT-PCR was also performed on half tick (HT) carcasses after SG dissection. Cytauxzoon felis RNA was detected in SGs of 17/140 ticks. Of these, 7/17 ticks had microscopic visualization via ISH and/or TEM. The remaining 10/17 ticks had only molecular detection of C. felis in SGs via RT-PCR without visualization. Cytauxzoon felis RNA was detected solely in HT carcasses via RT-PCR in 9/140 ticks. In ISH-positive tick SGs, hybridization signals were present in cytoplasms of SG acinar cells. TEM captured rare C. felis organisms with characteristic ultrastructural features of sporozoites. This study describes the first direct visualization of any developing stage of C. felis in ticks. Forthcoming studies should employ a combination of molecular and microscopic techniques to investigate the C. felis life cycle in A. americanum.}, number={1}, journal={TICKS AND TICK-BORNE DISEASES}, author={Yang, Tzushan S. and Reichard, Mason V and Thomas, Jennifer E. and Miller, Laura S. and Marr, Henry S. and Karounos, Michael and Bell, Aaron J. and Birkenheuer, Adam J.}, year={2023}, month={Jan} }
 @article{yang_reichard_thomas_marr_karounos_hyatt_miller_birkenheuer_2023, title={Transmission of Cytauxzoon felis by injection of Amblyomma americanum salivary glands}, volume={95}, ISSN={["1873-0329"]}, DOI={10.1016/j.parint.2023.102753}, abstractNote={Cytauxzoonosis is a life-threatening disease of cats, caused by the tick-borne piroplasmid hemoparasite, Cytauxzoon felis. Current experimental models for cytauxzoonosis rely on either tick transmission or direct injection of infected cat tissues. These models require researchers to directly work with infected ticks or use cats with acute cytauxzoonosis. To improve the feasibility and accessibility, there is a need to establish sharable resources among researchers. In related piroplasmid parasites, sporozoite-based inoculums are routinely produced from tick salivary glands, cryopreserved and distributed to other investigators and facilities. For these parasites, sporozoites have been the basis for vaccine development and in vitro cultivation, both of which remain lacking for C. felis research. If infectious sporozoites can be similarly isolated for C. felis, it would significantly broaden our capabilities to study this parasite. Aims of this study was to determine if C. felis sporozoites inoculums collected from the salivary glands of Amblyomma americanum ticks were capable of inducing cytauxzoonosis in naïve cats. A. americanum nymphs were acquisition-fed on a donor cat chronically infected with C. felis and allowed to molt to adults. Four groups of adult ticks (n = 50/group) were either stimulation-fed for 4 days on naïve cats or were heated at 37 °C for 4 days. After these treatments, salivary glands (SG) of each group of ticks were collected to create inoculums. Infectivity of these inoculums was then tested by subcutaneous injection into naïve cats. The two naïve cats used for stimulation feeding and as controls both developed cytauxzoonosis, indicating these groups of ticks were capable of producing infectious sporozoites. Of the 2 cats that were injected with SGs from the stimulation-fed ticks, one cat developed cytauxzoonosis and C. felis infection was confirmed by both light microscopy and PCR. The other cat did not develop cytauxzoonosis and only had equivocal evidence of infection. Neither cat injected with SGs from the heated ticks developed cytauxzoonosis. One of these cats had equivocal evidence of infection and one had no evidence of infection. This study validates the feasibility of collecting infectious sporozoites from C. felis-infected ticks that can be used to infect naïve cats. While this model requires further optimization, it has the potential to expand resources to study C. felis and further advance research in this field.}, journal={PARASITOLOGY INTERNATIONAL}, author={Yang, Tzushan S. and Reichard, Mason V and Thomas, Jennifer E. and Marr, Henry S. and Karounos, Michael and Hyatt, Julia and Miller, Craig and Birkenheuer, Adam J.}, year={2023}, month={Aug} }
 @article{yang_reichard_marr_cohn_nafe_whitehurst_birkenheuer_2022, title={Direct injection of Amblyomma americanum ticks with Cytauxzoon felis}, volume={13}, ISSN={["1877-9603"]}, DOI={10.1016/j.ttbdis.2021.101847}, abstractNote={Cytauxzoon felis is a tick-borne hemoprotozoan parasite that causes life-threatening disease in domestic cats in the United States. Currently, the platforms for C. felis research are limited to natural or experimental infection of domestic cats. This study aims to develop an alternative model by infecting Amblyomma americanum ticks with C. felis via direct injection. Amblyomma americanum adults were injected with C. felis-infected feline erythrocytes through two routes: directly into the digestive tract through the anal pore (IA injection), or percutaneously into the tick hemocoel (IH injection). RNAscope® in situ hybridization (ISH) was used to visualize the parasites within the ticks at different time points after injection. Four months after injection, ticks were divided into 3 infestation groups based on injection methods and inoculum type and fed on 3 naïve cats to assess the ticks’ ability to transmit C. felis. Prior to the transmission challenge, selected ticks from each infestation group were tested for C. felis RNA via reverse transcription-PCR (RT-PCR). In both IA- and IH-injected ticks, ISH signals were observed in ticks up to 3 weeks after injection. The number of hybridization signals notably decreased over time, and no signals were detected by 4 months after injection. Prior to the transmission challenge, 37–57% of the sampled ticks were positive for C. felis RNA via RT-PCR. While the majority of injected ticks successfully attached and fed to repletion on all 3 cats during the transmission challenge, none of the cats became infected with C. felis. These results suggest that injected C. felis remained alive in ticks but was unable to progress to infective sporozoites after injection. It is unclear why this infection technique had been successful for other closely related tick-borne hemoprotozoa and not for C. felis. This outcome may be associated with uncharacterized differences in the C. felis life cycle, the lack of the feeding or molting in our model or absence of gametocytes in the inoculum. Nonetheless, our study demonstrated the potential of using ticks as an alternative model to study C. felis. Future improvement of a tick model for C. felis should consider other tick species for the injection model or utilize infection methods that more closely emulate the natural infection process.}, number={1}, journal={TICKS AND TICK-BORNE DISEASES}, author={Yang, Tzushan S. and Reichard, Mason V and Marr, Henry S. and Cohn, Leah A. and Nafe, Laura and Whitehurst, Nathan and Birkenheuer, Adam J.}, year={2022}, month={Jan} }
 @article{hartley_marr_birkenheuer_2020, title={Cytauxzoon felis cytochrome b gene mutation associated with atovaquone and azithromycin treatment}, volume={34}, ISSN={["1939-1676"]}, DOI={10.1111/jvim.15935}, abstractNote={Abstract}, number={6}, journal={JOURNAL OF VETERINARY INTERNAL MEDICINE}, author={Hartley, Ashley N. and Marr, Henry S. and Birkenheuer, Adam J.}, year={2020}, month={Nov}, pages={2432–2437} }
 @article{wilson_breitschwerdt_juhasz_marr_galvao_pratt_qurollo_2020, title={Novel Rickettsia Species Infecting Dogs, United States}, volume={26}, ISSN={["1080-6059"]}, DOI={10.3201/eid2612.200272}, abstractNote={In 2018 and 2019, spotted fever was suspected in 3 dogs in 3 US states. The dogs had fever and hematological abnormalities; blood samples were Rickettsia seroreactive. Identical Rickettsia DNA sequences were amplified from the samples. Multilocus phylogenetic analysis showed the dogs were infected with a novel Rickettsia species related to human Rickettsia pathogens.}, number={12}, journal={EMERGING INFECTIOUS DISEASES}, author={Wilson, James M. and Breitschwerdt, Edward B. and Juhasz, Nicholas B. and Marr, Henry S. and Galvao, Joao Felipe de Brito and Pratt, Carmela L. and Qurollo, Barbara A.}, year={2020}, month={Dec}, pages={3011–3015} }
 @article{neupane_sevala_balakrishnan_marr_wilson_maggi_birkenheuer_lappin_chomel_breitschwerdt_2020, title={Validation of Bartonella henselae Western Immunoblotting for Serodiagnosis of Bartonelloses in Dogs}, volume={58}, ISSN={["1098-660X"]}, DOI={10.1128/JCM.01335-19}, abstractNote={
            Bartonella
            spp. are etiological agents of life-threatening zoonotic diseases in dogs worldwide. Due to the poor sensitivity of immunofluorescent-antibody assays (IFAs), a reliable serodiagnostic test for canine bartonelloses is of clinical importance. The utility of Western blotting (WB) for the serodiagnosis of canine bartonelloses has not been critically investigated. The objective of this study was to characterize WB immunodominant proteins that could be used to confirm a serodiagnosis of bartonelloses.
          }, number={4}, journal={JOURNAL OF CLINICAL MICROBIOLOGY}, author={Neupane, Pradeep and Sevala, Sindhura and Balakrishnan, Nandhakumar and Marr, Henry and Wilson, James and Maggi, Ricardo and Birkenheuer, Adam and Lappin, Michael and Chomel, Bruno and Breitschwerdt, Edward B.}, year={2020}, month={Apr} }
 @article{naor_lindemann_schreeg_marr_birkenheuer_carpenter_ryseff_2019, title={Clinical, morphological, and molecular characterization of an undetermined Babesia species in a maned wolf (Chrysocyon brachyurus)}, volume={10}, ISSN={["1877-9603"]}, DOI={10.1016/j.ttbdis.2018.09.005}, abstractNote={A possible novel Babesia species infection of a maned wolf (Chrysocyon brachyurus) was first reported in 2012. The current case details a confirmed report of a maned wolf with infection by an undetermined species of Babesia. As the mortality and morbidity of babesiosis is high, this may become a significant concern to captive maned wolves, which are considered a near-threatened species by the World Association of Zoos and Aquariums. The aim of this study is to report the clinical, morphological and molecular characterization of this Babesia species. A 2.5-year-old, intact female maned wolf was found laterally recumbent with pale mucous membranes and jaundice the morning of presentation. Hematological and serum biochemical data were consistent with babesiosis and showed a regenerative severe anemia, leukocytosis, thrombocytopenia, hyperbilirubinemia, azotemia, increased creatine phosphokinase and increase alanine aminotransferase. On blood film review, inclusion bodies were seen in the red blood cells with cytomorphological features that were most consistent with a small form Babesia species. A blood sample was sent for polymerase chain reaction (PCR) testing and multi-locus sequence analyses. These findings suggested a unique Babesia species that is most closely related to a Babesia species (Babesia sp. AJB-2006) that has been found to infect raccoons (Procyon lotor) in North America. Although the cytomorphological features of the piroplasms and the clinical presentation were similar in both the current and 2012 case, when comparing the 18S melt curve temperature of the two Babesia isolates, the peak temperature was different. Unfortunately, genetic material from the 2012 case was not available so comparison of multi-locus gene sequences could not be performed, excluding the possibility to definitively state if the Babesia spp. from both cases were distinct from each other. The maned wolf was treated with a whole blood transfusion, dexamethazone (0.28 mg/kg IM), azithromycin (10 mg/kg in NaCl SC), atavaquone (1.5 cc PO), and 2 imidocarb (6.6 mg/kg IM) injections, and clinically improved. These findings demonstrate the need to further characterize the molecular and epidemiological differences of the Babesia species in this case report and the Babesia species known to infect raccoons.}, number={1}, journal={TICKS AND TICK-BORNE DISEASES}, author={Naor, Adi Wasserkrug and Lindemann, Dana M. and Schreeg, Megan E. and Marr, Henry S. and Birkenheuer, Adam J. and Carpenter, James W. and Ryseff, Julia K.}, year={2019}, month={Jan}, pages={124–126} }
 @article{birkenheuer_marr_wilson_breitschwerdt_qurollo_2018, title={Babesia gibsoni
 cytochrome b mutations in canine blood samples submitted to a US veterinary diagnostic laboratory}, volume={32}, ISSN={0891-6640}, url={http://dx.doi.org/10.1111/jvim.15300}, DOI={10.1111/jvim.15300}, abstractNote={
Background: Babesiosis caused by Babesia gibsoni is recognized throughout the world and can be difficult to treat. Resistance to atovaquone is associated with mutations in the B. gibsoni mitochondrial genome, specifically the M128 position of cytochrome b (cytb). The prevalence of cytb mutations in North America has not been reported.}, number={6}, journal={Journal of Veterinary Internal Medicine}, publisher={Wiley}, author={Birkenheuer, Adam J. and Marr, Henry S. and Wilson, James M. and Breitschwerdt, Edward B. and Qurollo, Barbara A.}, year={2018}, month={Oct}, pages={1965–1969} }
 @article{neupane_hegarty_marr_maggi_birkenheuer_breitschwerdt_2018, title={Evaluation of cell culture-grown Bartonella
 antigens in immunofluorescent antibody assays for the serological diagnosis of bartonellosis in dogs}, volume={32}, ISSN={0891-6640}, url={http://dx.doi.org/10.1111/jvim.15301}, DOI={10.1111/jvim.15301}, abstractNote={BackgroundBecause of poor sensitivity and questionable specificity of immunofluorescent antibody assays (IFAs), serological diagnosis of Bartonella species infections in dogs remains challenging. Despite limitations, IFA testing is the historical “gold standard” for Bartonella serodiagnosis in animals and humans. Because most diagnostic laboratories test against only 1 or 2 Bartonella spp., testing against a broader panel of Bartonella antigens may enhance diagnostic sensitivity and specificity.}, number={6}, journal={Journal of Veterinary Internal Medicine}, publisher={Wiley}, author={Neupane, Pradeep and Hegarty, Barbara C. and Marr, Henry S. and Maggi, Ricardo G. and Birkenheuer, Adam J. and Breitschwerdt, Edward B.}, year={2018}, month={Oct}, pages={1958–1964} }
 @article{schreeg_marr_tarigo_sherrill_outi_scholl_bird_vigil_hung_nakajima_et al._2018, title={Identification of Cytauxzoon felis antigens via protein microarray and assessment of expression library immunization against cytauxzoonosis}, volume={15}, ISSN={["1559-0275"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85059281263&partnerID=MN8TOARS}, DOI={10.1186/s12014-018-9218-9}, abstractNote={Cytauxzoonosis is a disease of felids in North America caused by the tick-transmitted apicomplexan parasite Cytauxzoon felis. Cytauxzoonosis is particularly virulent for domestic cats, but no vaccine currently exists. The parasite cannot be cultivated in vitro, presenting a significant limitation for vaccine development.Recent sequencing of the C. felis genome has identified over 4300 putative protein-encoding genes. From this pool we constructed a protein microarray containing 673 putative C. felis proteins. This microarray was probed with sera from C. felis-infected and naïve cats to identify differentially reactive antigens which were incorporated into two expression library vaccines, one polyvalent and one monovalent. We assessed the efficacy of these vaccines to prevent of infection and/or disease in a tick-challenge model.Probing of the protein microarray resulted in identification of 30 differentially reactive C. felis antigens that were incorporated into the two expression library vaccines. However, expression library immunization failed to prevent infection or disease in cats challenged with C. felis.Protein microarray facilitated high-throughput identification of novel antigens, substantially increasing the pool of characterized C. felis antigens. These antigens should be considered for development of C. felis vaccines, diagnostics, and therapeutics.}, number={1}, journal={CLINICAL PROTEOMICS}, author={Schreeg, Megan E. and Marr, Henry S. and Tarigo, Jaime L. and Sherrill, Meredith K. and Outi, Hilton K. and Scholl, Elizabeth H. and Bird, David M. and Vigil, Adam and Hung, Chris and Nakajima, Rie and et al.}, year={2018}, month={Dec} }
 @article{mylonakis_schreeg_chatzis_pearce_marr_saridomichelakis_birkenheuer_2018, title={Molecular detection of vector-borne pathogens in Greek cats}, volume={9}, ISSN={["1877-9603"]}, DOI={10.1016/j.ttbdis.2017.08.013}, abstractNote={Infectious diseases have been increasingly recognized in cats worldwide. The objective of this study was the molecular investigation of the prevalence of selected pathogens in healthy and sick cats from Greece, a country highly endemic for several canine vector-borne pathogens. Blood and/or bone marrow samples from 50 clinically healthy and 50 sick adult (>1 year-old) cats were retrospectively examined for the amplification of Bartonella spp., haemoplasmas, Ehrlichia spp., Anaplasma spp., Babesia spp., and Cytauxzoon spp. DNA. Overall, 14.9% of the cats were found to be infected or co-infected by haemoplasmas, including Candidatus Mycoplasma haemominutum and M. haemofelis. In addition, 8.5% of the cats were infected by Bartonella henselae, Bartonella clarridgeiae or Bartonella koehlerae. In contrast, DNA of Ehrlichia spp., Anaplasma spp., Babesia spp. and Cytauxzoon spp. was not amplified from the blood or bone marrow of any cat. There was no significant difference in either haemoplasma or Bartonella infection rates when comparing healthy and sick cats. This study represents the first description of Bartonella koehlerae in Greek cats.}, number={2}, journal={TICKS AND TICK-BORNE DISEASES}, author={Mylonakis, Mathios E. and Schreeg, Megan and Chatzis, Manolis K. and Pearce, Julian and Marr, Henry S. and Saridomichelakis, Manolis N. and Birkenheuer, Adam J.}, year={2018}, month={Feb}, pages={171–175} }
 @article{levine_cianciolo_linder_bizikova_birkenheuer_brooks_salous_nordone_bellinger_marr_et al._2017, title={Endothelial alterations in a canine model of immune thrombocytopenia}, volume={30}, ISSN={0953-7104 1369-1635}, url={http://dx.doi.org/10.1080/09537104.2017.1378807}, DOI={10.1080/09537104.2017.1378807}, abstractNote={Abstract Bleeding heterogeneity amongst patients with immune thrombocytopenia (ITP) is poorly understood. Platelets play a role in maintaining endothelial integrity, and variable thrombocytopenia-induced endothelial changes may influence bleeding severity. Platelet-derived endothelial stabilizers and markers of endothelial integrity in ITP are largely underexplored. We hypothesized that, in a canine ITP model, thrombocytopenia would lead to alterations in the endothelial ultrastructure and that the Von Willebrand factor (vWF) would serve as a marker of endothelial injury associated with thrombocytopenia. Thrombocytopenia was induced in healthy dogs with an antiplatelet antibody infusion; control dogs received an isotype control antibody. Cutaneous biopsies were obtained prior to thrombocytopenia induction, at platelet nadir, 24 hours after nadir, and on platelet recovery. Cutaneous capillaries were assessed by electron microscopy for vessel thickness, the number of pinocytotic vesicles, the number of large vacuoles, and the number of gaps between cells. Pinocytotic vesicles are thought to represent an endothelial membrane reserve that can be used for repair of damaged endothelial cells. Plasma samples were assessed for vWF. ITP dogs had significantly decreased pinocytotic vesicle numbers compared to control dogs (P = 0.0357) and the increase in plasma vWF from baseline to 24 hours correlated directly with the endothelial large vacuole score (R = 0.99103; P < 0.0001). This direct correlation between plasma vWF and the number of large vacuoles, representing the vesiculo-vacuolar organelle (VVO), a permeability structure, suggests that circulating vWF could serve as a biomarker for endothelial alterations and potentially a predictor of thrombocytopenic bleeding. Overall, our results indicate that endothelial damage occurs in the canine ITP model and variability in the degree of endothelial damage may account for differences in the bleeding phenotype among patients with ITP.}, number={1}, journal={Platelets}, publisher={Informa UK Limited}, author={LeVine, Dana N. and Cianciolo, Rachel E. and Linder, Keith E. and Bizikova, Petra and Birkenheuer, Adam J. and Brooks, Marjory B. and Salous, Abdelghaffar K. and Nordone, Shila K. and Bellinger, Dwight A. and Marr, Henry and et al.}, year={2017}, month={Nov}, pages={88–97} }
 @article{qurollo_archer_schreeg_marr_birkenheuer_haney_thomas_breitschwerdt_2017, title={Improved molecular detection of Babesia infections in animals using a novel quantitative real-time PCR diagnostic assay targeting mitochondrial DNA}, volume={10}, ISSN={1756-3305}, url={http://dx.doi.org/10.1186/s13071-017-2064-1}, DOI={10.1186/s13071-017-2064-1}, abstractNote={Babesiosis is a protozoal, tick transmitted disease found worldwide in humans, wildlife and domesticated animals. Commonly used approaches to diagnose babesiosis include microscopic examination of peripheral blood smears, detection of circulating antibodies and PCR. To screen and differentiate canine Babesia infections many PCR assays amplify the 18S rRNA gene. These sequences contain hypervariable regions flanked by highly conserved regions allowing for amplification of a broad-range of Babesia spp. However, differences in the 18S rRNA gene sequence of distantly related clades can make it difficult to design assays that will amplify all Babesia species while excluding the amplification of other eukaryotes. By targeting Babesia mitochondrial genome (mtDNA), we designed a novel three primer qPCR with greater sensitivity and broader screening capabilities to diagnose and differentiate Babesia spp. Using 13 Babesia mtDNA sequences, a region spanning two large subunit rRNA gene fragments (lsu5-lsu4) was aligned to design three primers for use in a qPCR assay (LSU qPCR) capable of amplifying a wide range of Babesia spp. Plasmid clones were generated and used as standards to determine efficiency, linear dynamic range and analytical sensitivity. Animals naturally infected with vector-borne pathogens were tested retrospectively and prospectively to determine relative clinical sensitivity and specificity by comparing the LSU qPCR to an established 18S rDNA qPCR. The LSU qPCR efficiencies ranged between 92 and 100% with the limit of detection at five copies/reaction. The assay did not amplify mammalian host or other vector-borne pathogen gDNA except Cytauxzoon felis (a feline protozoal pathogen). The LSU qPCR assay amplified 12 different Babesia. sp. and C. felis from 31/31 (100%) archived samples, whereas the 18S qPCR amplified only 26/31 (83.9%). By prospective analysis, 19/394 diagnostic accessions (4.8%) were LSU qPCR positive, compared to 11/394 (2.8%) 18S rDNA qPCR positive. We have developed a more sensitive qPCR assay with a more expansive range of Babesia spp. detection by targeting a highly conserved region of mtDNA, when compared to an established 18S qPCR.}, number={1}, journal={Parasites & Vectors}, publisher={Springer Nature}, author={Qurollo, Barbara A. and Archer, Nikole R. and Schreeg, Megan E. and Marr, Henry S. and Birkenheuer, Adam J. and Haney, Kaitlin N. and Thomas, Brittany S. and Breitschwerdt, Edward B.}, year={2017}, month={Mar} }
 @article{schreeg_marr_tarigo_cohn_bird_scholl_levy_wiegmann_birkenheuer_2016, title={Mitochondrial Genome Sequences and Structures Aid in the Resolution of Piroplasmida phylogeny}, volume={11}, ISSN={["1932-6203"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84994744879&partnerID=MN8TOARS}, DOI={10.1371/journal.pone.0165702}, abstractNote={The taxonomy of the order Piroplasmida, which includes a number of clinically and economically relevant organisms, is a hotly debated topic amongst parasitologists. Three genera (Babesia, Theileria, and Cytauxzoon) are recognized based on parasite life cycle characteristics, but molecular phylogenetic analyses of 18S sequences have suggested the presence of five or more distinct Piroplasmida lineages. Despite these important advancements, a few studies have been unable to define the taxonomic relationships of some organisms (e.g. C. felis and T. equi) with respect to other Piroplasmida. Additional evidence from mitochondrial genome sequences and synteny should aid in the inference of Piroplasmida phylogeny and resolution of taxonomic uncertainties. In this study, we have amplified, sequenced, and annotated seven previously uncharacterized mitochondrial genomes (Babesia canis, Babesia vogeli, Babesia rossi, Babesia sp. Coco, Babesia conradae, Babesia microti-like sp., and Cytauxzoon felis) and identified additional ribosomal fragments in ten previously characterized mitochondrial genomes. Phylogenetic analysis of concatenated mitochondrial and 18S sequences as well as cox1 amino acid sequence identified five distinct Piroplasmida groups, each of which possesses a unique mitochondrial genome structure. Specifically, our results confirm the existence of four previously identified clades (B. microti group, Babesia sensu stricto, Theileria equi, and a Babesia sensu latu group that includes B. conradae) while supporting the integration of Theileria and Cytauxzoon species into a single fifth taxon. Although known biological characteristics of Piroplasmida corroborate the proposed phylogeny, more investigation into parasite life cycles is warranted to further understand the evolution of the Piroplasmida. Our results provide an evolutionary framework for comparative biology of these important animal and human pathogens and help focus renewed efforts toward understanding the phylogenetic relationships within the group.}, number={11}, journal={PLOS ONE}, author={Schreeg, Megan E. and Marr, Henry S. and Tarigo, Jaime L. and Cohn, Leah A. and Bird, David M. and Scholl, Elizabeth H. and Levy, Michael G. and Wiegmann, Brian M. and Birkenheuer, Adam J.}, year={2016}, month={Nov} }
 @article{schreeg_marr_griffith_tarigo_bird_reichard_cohn_levy_birkenheuer_2016, title={PCR amplification of a multi-copy mitochondrial gene (cox3) improves detection of Cytauxzoon felis infection as compared to a ribosomal gene (18S)}, volume={225}, ISSN={["1873-2550"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84975504702&partnerID=MN8TOARS}, DOI={10.1016/j.vetpar.2016.06.013}, abstractNote={Cytauxzoon felis is a tick-transmitted protozoan parasite that infects felids. Clinical disease caused by acute C. felis infection rapidly progresses in domestic cats, leading to high morbidity and mortality. Accurately diagnosing cytauxzoonosis as soon as possible during acute infection would allow for earlier initiation of antiprotozoal therapy which could lead to higher survival rates. Molecular detection of parasite rRNA genes (18S) by PCR has previously been shown to be a sensitive method of diagnosing C. felis infections. Based on evidence from related apicomplexan species, we hypothesized that C. felis mitochondrial genes would exist at higher copy numbers than 18S and would be a more sensitive diagnostic target. In this study we have designed a PCR assay targeting the C. felis mitochondrial gene cytochrome c oxidase subunit III (cox3). Herein we demonstrate that (1) the cox3 PCR can detect as low as 1 copy of DNA target and can detect C. felis in samples with known mitochondrial sequence heterogeneity, (2) cox3 copy number is increased relative to 18S in blood and tissue samples from acutely infected cats, and (3) the cox3 PCR is more sensitive than 18S PCR for detection of C. felis during early infections.}, journal={VETERINARY PARASITOLOGY}, author={Schreeg, Megan E. and Marr, Henry S. and Griffith, Emily H. and Tarigo, Jaime L. and Bird, David M. and Reichard, Mason V. and Cohn, Leah A. and Levy, Michael G. and Birkenheuer, Adam J.}, year={2016}, month={Jul}, pages={123–130} }
 @article{schreeg_marr_tarigo_cohn_levy_birkenheuer_2015, title={Rapid High-Resolution Melt Analysis of Cytauxzoon felis Cytochrome b To Aid in the Prognosis of Cytauxzoonosis}, volume={53}, ISSN={["1098-660X"]}, DOI={10.1128/jcm.00635-15}, abstractNote={ABSTRACT}, number={8}, journal={JOURNAL OF CLINICAL MICROBIOLOGY}, author={Schreeg, Megan E. and Marr, Henry S. and Tarigo, Jaime L. and Cohn, Leah A. and Levy, Michael G. and Birkenheuer, Adam J.}, year={2015}, month={Aug}, pages={2517–2524} }
 @article{levy_powers_gore_marr_2015, title={Spironucleus meleagridis, an enteric diplomonad protozoan of cockatiels (Nymphicus hollandicus): Preliminary molecular characterization and association with clinical disease}, volume={208}, ISSN={["1873-2550"]}, DOI={10.1016/j.vetpar.2014.12.028}, abstractNote={A flagellated enteric diplomonad protozoan consistent with Spironucleus meleagridis (formerly Hexamita meleagridis) associated with gastrointestinal disease and mortality in psittacine birds including cockatiels (Nymphicus hollandicus) has been sporadically described in the literature. However, molecular characterization of psittacine protozoal isolates had not yet been performed. The 16S rRNA gene from a protozoan persistently shed in the feces in a small group of cockatiels demonstrated a 98% molecular identity with S. meleagridis isolated from turkeys. Based on these sequence data, a diagnostic PCR assay was developed to detect the presence of S. meleagridis. Nineteen privately owned pet cockatiels from unrelated households were clinically evaluated. All birds microscopically positive for this organism were PCR positive, with several additional birds microscopically negative but PCR positive. Many of the birds identified as positive for S. meleagridis by fecal PCR had signs of gastrointestinal disease such as diarrhea, soft feces, and melena, whereas none of the birds that tested negative had gastrointestinal signs. Examination of feces from two unrelated cockatiel breeding facilities revealed 70% and 86% PCR positive rates. Prevalence of infection and incidence of clinical disease, including factors that lead to clinical manifestation such as viral, bacterial, or mycotic coinfections, are not yet known and warrant further study, but spironucleosis is likely an under-recognized disease in cockatiels.}, number={3-4}, journal={VETERINARY PARASITOLOGY}, author={Levy, M. G. and Powers, L. V. and Gore, K. C. and Marr, H. S.}, year={2015}, month={Mar}, pages={169–173} }
 @article{levine_birkenheuer_brooks_nordone_bellinger_jones_fischer_oglesbee_frey_brinson_et al._2014, title={A novel canine model of immune thrombocytopenia: has immune thrombocytopenia (ITP) gone to the dogs?}, volume={167}, ISSN={0007-1048}, url={http://dx.doi.org/10.1111/bjh.13005}, DOI={10.1111/bjh.13005}, abstractNote={Summary}, number={1}, journal={British Journal of Haematology}, publisher={Wiley}, author={LeVine, Dana N. and Birkenheuer, Adam J. and Brooks, Marjory B. and Nordone, Shila K. and Bellinger, Dwight A. and Jones, Sam L. and Fischer, Thomas H. and Oglesbee, Stephen E. and Frey, Kahlina and Brinson, Nicole S. and et al.}, year={2014}, month={Jul}, pages={110–120} }
 @article{lewis_cohn_marr_birkenheuer_2014, title={Failure of efficacy and adverse events associated with dose-intense diminazene diaceturate treatment of chronic Cytauxzoon felis infection in five cats}, volume={16}, ISSN={["1532-2750"]}, DOI={10.1177/1098612x13502974}, abstractNote={ Cytauxzoon felis is a hemoprotozoan parasite of cats. While many infected cats die of acute illness, some enter a chronic carrier state. To date, no treatment has been documented to clear the chronic carrier state, leaving recovered cats to act as a potential indirect source of infection via a tick vector. Diminazene diaceturate is an anti-protozoal therapy that has been suggested for use in the treatment of acute cytauxzoonosis, but which failed to clear the carrier state at the dose used in acute illness. We hypothesized that a dose-intensified regimen of diminazene could reduce or eliminate parasitemia from five domestic cats naturally infected with C felis. Cats were administered 4 mg/kg of diminazene diaceturate intramuscularly for 5 consecutive days. Clearance of the organism was assessed via semi-quantitative polymerase chain reaction and light microscopy 1, 3, 6 and 10 weeks after starting treatment. Additionally, cats were monitored for adverse drug reactions by daily observation and examination. Complete blood count, biochemical profile and urinalysis were performed at 1, 3 and 10 weeks. Adverse events were common and included profuse salivation and nausea at the time of injection, monoparesis in the injected leg, proteinuria and potential hepatotoxicity. Severity of parasitemia was not reduced. Diminazene diaceturate cannot be recommended for elimination of the carrier state of C felis infection. }, number={2}, journal={JOURNAL OF FELINE MEDICINE AND SURGERY}, author={Lewis, Kristin M. and Cohn, Leah A. and Marr, Henry S. and Birkenheuer, Adam J.}, year={2014}, month={Feb}, pages={157–163} }
 @article{floras_holowaychuk_hodgins_marr_birkenheuer_sharif_bersenas_bienzle_2014, title={Investigation of a Commercial ELISA for the Detection of Canine Procalcitonin}, volume={28}, ISSN={["1939-1676"]}, DOI={10.1111/jvim.12309}, abstractNote={BackgroundRapid identification of sepsis enables prompt administration of antibiotics and is essential to improve patient survival. Procalcitonin (PCT) is a biomarker used to diagnose sepsis in people. Commercial assays to measure canine PCT peptide have not been validated.}, number={2}, journal={JOURNAL OF VETERINARY INTERNAL MEDICINE}, author={Floras, A. N. K. and Holowaychuk, M. K. and Hodgins, D. C. and Marr, H. S. and Birkenheuer, A. and Sharif, S. and Bersenas, A. M. E. and Bienzle, D.}, year={2014}, month={Mar}, pages={599–602} }
 @article{schreeg_marr_tarigo_cohn_levy_birkenheuer_2013, title={Pharmacogenomics of Cytauxzoon felis Cytochrome b: Implications for Atovaquone and Azithromycin Therapy in Domestic Cats with Cytauxzoonosis}, volume={51}, ISSN={["0095-1137"]}, DOI={10.1128/jcm.01407-13}, abstractNote={ABSTRACT}, number={9}, journal={JOURNAL OF CLINICAL MICROBIOLOGY}, author={Schreeg, Megan E. and Marr, Henry S. and Tarigo, Jaime and Cohn, Leah A. and Levy, Michael G. and Birkenheuer, Adam J.}, year={2013}, month={Sep}, pages={3066–3069} }
 @article{holowaychuk_birkenheuer_li_marr_boll_nordone_2012, title={Hypocalcemia and Hypovitaminosis D in Dogs with Induced Endotoxemia}, volume={26}, ISSN={["0891-6640"]}, DOI={10.1111/j.1939-1676.2012.00886.x}, abstractNote={BackgroundHypocalcemia is a documented electrolyte disturbance in people and animals with sepsis, but its mechanism is poorly understood.}, number={2}, journal={JOURNAL OF VETERINARY INTERNAL MEDICINE}, author={Holowaychuk, M. K. and Birkenheuer, A. J. and Li, J. and Marr, H. and Boll, A. and Nordone, S. K.}, year={2012}, pages={244–251} }
 @article{di cicco_downey_beeler_marr_cyrog_kidd_diniz_cohn_birkenheuer_2012, title={Re-emergence of Babesia conradae and effective treatment of infected dogs with atovaquone and azithromycin}, volume={187}, ISSN={["0304-4017"]}, DOI={10.1016/j.vetpar.2012.01.006}, abstractNote={Babesia conradae (B. conradae) causes hemolytic anemia in dogs. This organism has not been reported clinically since it was originally described in southern California in 1991. To date, no anti-protozoal therapies have been associated with clearance of B. conradae. This report describes the use of atovaquone and azithromycin for the treatment of dogs naturally infected with B. conradae and report the re-emergence of B. conradae in southern California. Twelve dogs naturally infected with B. conradae were identified by practicing veterinarians and public health officials in southern California. Treatments consisted of a 10 day course of atovaquone (13.3mg/kg PO q 8h) and azithromycin (10-12.5mg/kg PO q 24h). Four dogs were treated in a randomized blinded placebo-controlled fashion, four additional cases were treated in a non-random, non-blinded fashion and one dog received no treatment. All dogs were tested for B. conradae DNA by polymerase chain reaction (PCR) initially and then once or 3 times post treatment (60-210 days). B. conradae infected dogs that received treatment did not have any detectable Babesia DNA by PCR after treatment. In contrast, dogs receiving placebo had detectable Babesia DNA by PCR throughout the study period. Combination therapy with atovaquone and azithromycin appears to be effective for acute and chronic babesiosis caused by B. conradae.}, number={1-2}, journal={VETERINARY PARASITOLOGY}, author={Di Cicco, Michael F. and Downey, Megan E. and Beeler, Emily and Marr, Henry and Cyrog, Peter and Kidd, Linda and Diniz, Pedro Paulo V. P. and Cohn, Leah A. and Birkenheuer, Adam J.}, year={2012}, month={Jun}, pages={23–27} }
 @article{li_birkenheuer_marr_levy_yoder_nordone_2011, title={Expression and function of triggering receptor expressed on myeloid cells-1 (TREM-1) on canine neutrophils}, volume={35}, ISSN={0145-305X}, url={http://dx.doi.org/10.1016/j.dci.2011.03.021}, DOI={10.1016/j.dci.2011.03.021}, abstractNote={The dog is both a valued veterinary species and a widely used translational model for sepsis research. However, relatively little work has been performed evaluating potential biomarkers present during canine infection. Triggering receptor expressed on myeloid cells-1 (TREM-1) has shown promise as a biomarker for infection and pneumonia in humans. Here we describe, for the first time, the expression and function of the canine orthologue of TREM-1. Expression of TREM-1 on canine neutrophils is significantly up-regulated by stimulation with microbial agonists of TLR2/6, TLR1/2, and TLR4/MD2. Kinetics of TREM-1 protein up-regulation are rapid, with significant increases observed within 2 hr of neutrophil activation. Functionally, canine TREM-1 synergistically enhances LPS-induced production of IL-8, TNF-α and a canine orthologue of CXCL1. Collectively, these data suggest that TREM-1 expression in dogs, as it is in humans, is an amplifier of pro-inflammatory responses to microbial products. These results have direct application to veterinary diagnostics as well as the potential to enhance the utility of canine disease models in the assessment of potential therapeutics in the treatment of human sepsis.}, number={8}, journal={Developmental & Comparative Immunology}, publisher={Elsevier BV}, author={Li, Jingjing and Birkenheuer, Adam J. and Marr, Henry S. and Levy, Michael G. and Yoder, Jeffrey A. and Nordone, Shila K.}, year={2011}, month={Aug}, pages={872–880} }
 @article{birkenheuer_horney_bailey_scott_sherbert_catto_marr_camacho_ballman_2010, title={Babesia microti-like infections are prevalent in North American foxes}, volume={172}, ISSN={["1873-2550"]}, DOI={10.1016/j.vetpar.2010.05.020}, abstractNote={Babesia microti-like organisms have recently been identified as a cause of hemolytic anemia and azotemia in European dogs. A genetically and morphologically similar B. microti-like parasite has been identified in two foxes from North America. In order to assess the prevalence of this parasite in North American wild canids we screened blood samples from coyotes (Canis latrans) and red foxes (Vulpes vulpes) from eastern Canada and red foxes and gray foxes (Urocyon cinereoargenteus) from North Carolina, USA for the presence B. microti-like DNA by polymerase chain reaction. Thirty-nine percent (50/127) of the red fox samples, 26% (8/31) of the gray fox samples and none (0/12) from the coyote samples tested positive for the presence of B. microti-like DNA. Partial 18S ribosomal ribonucleic acid and beta-tubulin genes from the North American B. microti-like parasites of foxes were sequenced and samples from six domestic dogs from Spain that were infected with a B. microti-like parasite were analyzed for comparison. Partial 18S ribosomal ribonucleic acid and beta-tubulin gene sequences from the North American B. microti-like parasites of foxes were nearly identical to those previously reported from foxes as well as those from domestic dogs from Spain characterized in this study. Interestingly, partial beta-tubulin gene sequences characterized from the B. microti-like parasites of domestic dogs from Spain in this study were different from those previously reported from a Spanish domestic dog sample which is believed to be a pseudogene. The ability of the North American B. microti-like parasite to infect and induce disease in domestic dogs remains unknown. Further studies investigating the pathogenic potential of the North American B. microti-like parasite in domestic dogs are indicated.}, number={3-4}, journal={VETERINARY PARASITOLOGY}, author={Birkenheuer, Adam J. and Horney, Barbara and Bailey, Matthew and Scott, McBurney and Sherbert, Brittany and Catto, Victoria and Marr, Henry S. and Camacho, Angel-Tomas and Ballman, Anne E.}, year={2010}, month={Sep}, pages={179–182} }
 @article{chinnadurai_birkenheuer_blanton_maggi_belfiore_marr_breitschwerdt_stoskopf_2010, title={Prevalence of Selected Vector-borne Organisms and Identification of Bartonella Species DNA in North American River Otters (Lontra canadensis)}, volume={46}, ISSN={0090-3558}, url={http://dx.doi.org/10.7589/0090-3558-46.3.947}, DOI={10.7589/0090-3558-46.3.947}, abstractNote={Trapper-killed North American river otters (Lontra canadensis) in North Carolina, USA, were screened for multiple vector-borne bacteria known to be pathogenic to mammals. Blood was collected from 30 carcasses in 2006, from 35 in 2007, and from one live otter in 2008. Samples were screened using conventional polymerase chain reaction (PCR) tests for DNA from Bartonella spp., Ehrlichia spp., and spotted fever group Rickettsia spp. All samples were negative for Rickettsia spp. Twelve of 30 samples from 2006 produced amplicons using the assay designed to detect Ehrlichia spp., but sequencing revealed that the amplified DNA fragment was from a novel Wolbachia sp., thought to be an endosymbiote of a Dirofilaria sp. Between 2006 and 2007, DNA from a novel Bartonella sp. was detected in 19 of 65 animals (29%). Blood from one live otter captured in 2008 was found positive for this Bartonella sp. by both PCR and culture. The pathogenicity of this Bartonella species in river otters or other mammals is unknown.}, number={3}, journal={Journal of Wildlife Diseases}, publisher={Wildlife Disease Association}, author={Chinnadurai, Sathya K. and Birkenheuer, Adam J. and Blanton, Hunter L. and Maggi, Ricardo G. and Belfiore, Natalia and Marr, Henry S. and Breitschwerdt, Edward B. and Stoskopf, Michael K.}, year={2010}, month={Jul}, pages={947–950} }
 @article{duncan_marr_birkenheuer_maggi_williams_correa_breitschwerdt_2008, title={Bartonella DNA in the Blood and Lymph Nodes of Golden Retrievers with Lymphoma and in Healthy Controls}, volume={22}, ISSN={0891-6640 1939-1676}, url={http://dx.doi.org/10.1111/j.1939-1676.2007.0018.x}, DOI={10.1111/j.1939-1676.2007.0018.x}, abstractNote={Background:Although lymphoma is the most common neoplastic process reported in dogs, its precise etiology is unknown. Golden Retrievers are more likely to develop lymphoma, suggesting a breed predisposition; however, other factors, including environment, immunity, and infection, are likely contributors to oncogenesis.}, number={1}, journal={Journal of Veterinary Internal Medicine}, publisher={Wiley}, author={Duncan, A.W. and Marr, H.S. and Birkenheuer, A.J. and Maggi, R.G. and Williams, L.E. and Correa, M.T. and Breitschwerdt, E.B.}, year={2008}, month={Jan}, pages={89–95} }
 @article{birkenheuer_marr_warren_acton_mucker_humphreys_tucker_2008, title={Cytauxzoon felis infections are present in bobcats (Lynx rufus) in a region where cytauxzoonosis is not recognized in domestic cats}, volume={153}, ISSN={["1873-2550"]}, DOI={10.1016/j.vetpar.2008.01.020}, abstractNote={This study was performed to determine the prevalence of Cytauxzoon felis (C. felis) infections in bobcats (Lynx rufus) from a region where C. felis is recognized in domestic cats, North Carolina (NC), and a region where C. felis is not recognized in domestic cats, Pennsylvania (PA). Samples from NC (n=32) were obtained post-mortem via cardiac puncture from legally trapped bobcats. Samples from PA (n=70) were collected post-mortem onto Nobuto blood collecting strips by the PA Game Commission. Each sample was tested using a C. felis specific PCR assay as well as a PCR assay targeting host DNA to rule out the presence of PCR inhibitors. Three samples were excluded due to the presence of PCR inhibitors. Thirty-three percent (10/30) of the samples from NC and 7% (5/69) of the samples from PA tested positive for the presence of C. felis. The proportion of C. felis positive bobcats from NC was significantly different than that from PA (P<0.005). Despite the lower prevalence of C. felis infections in bobcats from PA this finding is unique and indicates the potential for C. felis infections in domestic cats in the northeastern USA if the appropriate tick vectors are present. Veterinary practitioners in PA should be on alert for cytauxzoonosis in domestic cats. Further studies about the epidemiology and transmission of C. felis infections among both domestic cats and bobcats are needed.}, number={1-2}, journal={VETERINARY PARASITOLOGY}, author={Birkenheuer, Adam J. and Marr, Henry S. and Warren, Camille and Acton, Anne E. and Mucker, Eric M. and Humphreys, Jan G. and Tucker, Melissa D.}, year={2008}, month={May}, pages={126–130} }
 @article{stauffer_birkenheuer_levy_marr_gookin_2008, title={Evaluation of four DNA extraction methods for the detection of Tritrichomonas foetus in feline stool specimens by polymerase chain reaction}, volume={20}, ISSN={["1943-4936"]}, DOI={10.1177/104063870802000518}, abstractNote={ Feces are increasingly valued as practical samples for molecular diagnosis of infectious disease. However, extraction of polymerase chain reaction (PCR) quality DNA from fecal samples can be challenging because of coextraction of PCR inhibitors. Because the type and quantity of PCR inhibitors is influenced by diet, endogenous flora, and concurrent disease, it is unlikely that extraction method performance with human feces can be directly extrapolated to that of domestic cats. In the present study, 4 commercially available DNA extraction methods were examined for their influence on the sensitivity of PCR for the detection of Tritrichomonas foetus in feline stool. DNA was extracted from serially diluted feline-origin T. foetus trophozoites in the absence or presence of feline feces. The ZR Fecal DNA kit was identified as affording the greatest analytical sensitivity and reproducibility and was able to detect ≥10 T. foetus organisms per 100 mg feces in 100% of PCR reactions. Further, the identified extraction method could be completed in the shortest time of all kits tested. }, number={5}, journal={JOURNAL OF VETERINARY DIAGNOSTIC INVESTIGATION}, author={Stauffer, Stephen H. and Birkenheuer, Adam J. and Levy, Michael G. and Marr, Henry and Gookin, Jody L.}, year={2008}, month={Sep}, pages={639–641} }
 @article{hawkins_johnson_guptill_marr_breitschwerdt_birkenheuer_2008, title={Failure to identify an association between serologic or molecular evidence ofBartonellainfection and idiopathic rhinitis in dogs}, volume={233}, ISSN={0003-1488}, url={http://dx.doi.org/10.2460/javma.233.4.597}, DOI={10.2460/javma.233.4.597}, abstractNote={Abstract}, number={4}, journal={Journal of the American Veterinary Medical Association}, publisher={American Veterinary Medical Association (AVMA)}, author={Hawkins, Eleanor C. and Johnson, Lynelle R. and Guptill, Lynn and Marr, Henry S. and Breitschwerdt, Edward B. and Birkenheuer, Adam J.}, year={2008}, month={Aug}, pages={597–599} }
 @article{birkenheuer_marr_hladio_acton_2008, title={Molecular evidence of prevalent dual piroplasma infections in North American raccoons (Procyon lotor)}, volume={135}, ISSN={["1469-8161"]}, DOI={10.1017/S0031182007003538}, abstractNote={SUMMARY}, number={1}, journal={PARASITOLOGY}, author={Birkenheuer, A. J. and Marr, H. S. and Hladio, N. and Acton, A. E.}, year={2008}, month={Jan}, pages={33–37} }
 @article{valentine_harms_cadenas_birkenheuer_marr_braun-mcneill_maggi_breitschwerdt_2007, title={Bartonella DNA in Loggerhead Sea Turtles}, volume={13}, ISSN={1080-6040 1080-6059}, url={http://dx.doi.org/10.3201/eid1306.061551}, DOI={10.3201/eid1306.061551}, abstractNote={To the Editor: Bartonella are fastidious, aerobic, gram-negative, facultative, intracellular bacteria that infect erythrocytes, erythroblasts, endothelial cells, monocytes, and dendritic cells, and are transmitted by arthropod vectors or by animal scratches or bites (1–6). Currently, 20 species or subspecies of Bartonella have been characterized, of which 8 are known zoonotic pathogens (7). B. henselae has been recently identified from canine blood (8) and from harbor porpoises (9). Pathogenic bacteria are an important threat in terrestrial and marine environments, and in the case of B. henselae, reservoir hosts may be more diverse than currently recognized.}, number={6}, journal={Emerging Infectious Diseases}, publisher={Centers for Disease Control and Prevention (CDC)}, author={Valentine, K. Hope and Harms, Craig A. and Cadenas, Maria B. and Birkenheuer, Adam J. and Marr, Henry S. and Braun-McNeill, Joanne and Maggi, Ricardo G. and Breitschwerdt, Edward B.}, year={2007}, month={Jun}, pages={949–950} }
 @article{hawkins_birkenheuer_marr_rogala_large_adler_2007, title={Quantification of mucin gene expression in tracheobronchial epithelium of healthy dogs and dogs with chronic bronchitis}, volume={68}, ISSN={["1943-5681"]}, DOI={10.2460/ajvr.68.4.435}, abstractNote={Abstract}, number={4}, journal={AMERICAN JOURNAL OF VETERINARY RESEARCH}, author={Hawkins, Eleanor C. and Birkenheuer, Adam J. and Marr, Henry S. and Rogala, Allison R. and Large, Edward E. and Adler, Kenneth B.}, year={2007}, month={Apr}, pages={435–440} }
 @article{haber_tucker_marr_levy_burgess_lappin_birkenheuer_2007, title={The detection of Cytauxzoon felis in apparently healthy free-roaming cats in the USA}, volume={146}, ISSN={["1873-2550"]}, DOI={10.1016/j.vetpar.2007.02.029}, abstractNote={Cytauxzoon felis typically causes fatal disease in domestic cats. Survival after infection and persistent parasitemia without clinical illness has been documented in a few cases. To our knowledge there are no prevalence studies of C. felis in domestic cats. The purpose of this study was to estimate the prevalence of C. felis infected cats that were presented to trap-neuter-return programs in Florida, North Carolina and Tennessee. Cats that were presented to trap-neuter-return programs were tested using a C. felis-specific PCR assay. A total of 961 domestic cats were tested (494 from Florida; 392 from North Carolina; 75 from Tennessee). Prevalence of C. felis infection in this population was 0.3%. Two cats from Florida and one cat from Tennessee tested positive for the presence of C. felis DNA. These amplicons were sequenced and confirmed to be C. felis. The cat from Tennessee was alive without evidence of illness 2 months post-surgery. The other two cats were alive 24 h post-surgery, but were then lost to follow-up. This is the first report documenting C. felis infections in free-roaming cats. Despite the low prevalence rate, the presence of apparently healthy infected free-roaming cats suggests that they may have the capacity to serve as an additional reservoir host for C. felis. Further investigations should evaluate the potential vector competence of domestic cats as well as the role of chronically infected cats in areas in which cytauxzoonosis appears hyperendemic.}, number={3-4}, journal={VETERINARY PARASITOLOGY}, author={Haber, Marion D. and Tucker, Melissa D. and Marr, Henry S. and Levy, Julie K. and Burgess, Jill and Lappin, Michael R. and Birkenheuer, Adam J.}, year={2007}, month={May}, pages={316–320} }
 @article{birkenheuer_harms_neel_marr_tucker_acton_tuttle_stoskopf_2007, title={The identification of a genetically unique piroplasma in North American river otters (Lontra canadensis)}, volume={134}, ISSN={["1469-8161"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-34249725062&partnerID=MN8TOARS}, DOI={10.1017/S0031182006002095}, abstractNote={SUMMARY}, number={5}, journal={PARASITOLOGY}, author={Birkenheuer, A. J. and Harms, C. A. and Neel, J. and Marr, H. S. and Tucker, M. D. and Acton, A. E. and Tuttle, A. D. and Stoskopf, M. K.}, year={2007}, month={May}, pages={631–635} }
 @article{birkenheuer_marr_alleman_levy_breitschwerdt_2006, title={Development and evaluation of a PCR assay for the detection of Cytauxzoon felis DNA in feline blood samples}, volume={137}, ISSN={["1873-2550"]}, DOI={10.1016/j.vetpar.2005.12.007}, abstractNote={Cytauxzoonosis is an emerging tick borne infectious disease of domestic cats in the United States, caused by the organism Cytauxzoon felis (C. felis). In naturally infected domestic cats the disease is almost always fatal. Currently there are no commercially available molecular or serologic tests to facilitate the antemortem diagnosis of C. felis infection. Clinical and pathological diagnosis of cytauxzoonosis is based on microscopic identification of parasites in tissues or on blood smears. We have developed and evaluated the sensitivity and specificity of a polymerase chain reaction (PCR) based assay for the diagnosis of C. felis infections in feline blood samples. The assay is sensitive enough to detect one copy of a cloned fragment of the C. felis 18S rRNA gene. This PCR assay can be used for the rapid clinical diagnosis of cytauxzoonosis and for epidemiological studies that will better define the geographic distribution of C. felis infection in cats.}, number={1-2}, journal={VETERINARY PARASITOLOGY}, author={Birkenheuer, AJ and Marr, H and Alleman, AR and Levy, MG and Breitschwerdt, EB}, year={2006}, month={Apr}, pages={144–149} }