Michael J Yabsley

Publications of Michael J Yabsley

• Isolation, mouse pathogenicity, and genotyping of Trypanosoma cruzi from an English Cocker Spaniel from Virginia, USA.

  Authors: Jay M Patel, Alexa C Rosypal, Kurt L Zimmerman, William E Monroe, Nammalwar Sriranganathan, Anne M Zajac, Michael J Yabsley, David S Lindsay

  Veterinary parasitology. 01/2012;

  Trypanosoma cruzi was demonstrated in blood smears and heart tissue from a 5-year old, female, English Cocker Spaniel that had never been outside of the state of Virginia, USA. Plasma from the dogTrypanosoma cruzi was demonstrated in blood smears and heart tissue from a 5-year old, female, English Cocker Spaniel that had never been outside of the state of Virginia, USA. Plasma from the dog was positive in a commercially available immunochromatographic dipstick assay for T. cruzi and negative in an immunochromatographic dipstick assay for visceral Leishmania spp. The plasma from the dog had an indirect immunofluorescent antibody titer of 1:800 against epimastigotes of T. cruzi while the titer was 1:50 against promastigotes of L. infantum. The parasite was isolated from the blood in vitro from the dog (TcVT-1 isolate) and used to experimentally infect female C3H and ICR mice. The parasite was nonpathogenic for experimentally inoculated mice. DNA was isolated from parasites grown in vitro and used to determine that the genotype of T. cruzi present in the dog was genotype TcIV. This genotype is common in raccoons, Procyon lotor, in North America and suggests that raccoons may serve as reservoirs for canine infection.

• Parasites and vector-borne pathogens of southern plains woodrats (Neotoma micropus) from southern Texas.

  Authors: Roxanne A Charles, Sonia Kjos, Angela E Ellis, J P Dubey, Barbara C Shock, Michael J Yabsley

  Parasitology research. 11/2011;

  From 2008 to 2010, southern plains woodrats (Neotoma micropus) from southern Texas, were examined for parasites and selected pathogens. Eight helminth species were recovered from 97 woodratsFrom 2008 to 2010, southern plains woodrats (Neotoma micropus) from southern Texas, were examined for parasites and selected pathogens. Eight helminth species were recovered from 97 woodrats including, Trichuris neotomae from 78 (prevalence = 80%), Ascarops sp. from 42 (43%), Nematodirus neotoma from 31 (32%), Raillietina sp. from nine (9%), Taenia taeniaeformis larvae from eight (8%), and an unidentified spiurid, a Scaphiostomum sp. and a Zonorchis sp. each from a single woodrat. Besnotia neotomofelis was detected in three (3%) woodrats and microfilaria were detected in seven (7%). Polymerase chain reaction (PCR) testing of blood samples from 104 woodrats detected a novel Babesia sp. in one (1%) and Hepatozoon sp. in 17 (16%) woodrats. Partial 18S rRNA gene sequence of the Babesia was 94% similar to B. conradae. Histologic examination of tissues detected intestinal coccidia in seven of 104 (7%), Sarcocystis neotomafelis in 26 (25%), Hepatozoon sp. in 21 (20%), and Dunnifilaria meningica in four (4%) woodrats. Three woodrats (5%) were seropositive for Toxoplasma gondii. Ectoparasites recovered included fleas (Orchopeas sexdentatus and O. neotomae), ticks (Ixodes woodi and Ornithodoros turicata), mites (Trombicula sp. and Ornithonyssus (Bdellonyssus) bacoti) and bot flies (Cuterebra sp.). The only difference in prevalence related to gender was for N. neotoma (males > females, p = 0.029). Prevalence of T. neotomae and all intestinal parasites combined was significantly higher in adults compared with juveniles (p = 0.0068 and p = 0.0004), respectively. Lesions or clinical signs were associated with Cuterebra and B. neotomofelis. Collectively, these data indicate that woodrats from southern Texas harbor several parasites of veterinary and/or medical importance.

• Isospora troglodytes n. sp. (Apicomplexa: Eimeriidae), a new coccidian species from wrens of Costa Rica.

  Authors: Shamus P Keeler, Michael J Yabsley, Julie M Fox, Sabrina N McGraw, Sonia M Hernandez

  Parasitology research. 10/2011;

  Nineteen (91%) of 21 rufous-and-white wrens (Thryothorus rufalbus) and five (71%) of seven plain wrens (Cantorchilus modestus) sampled from Costa Rica were positive for a new species of Isospora.Nineteen (91%) of 21 rufous-and-white wrens (Thryothorus rufalbus) and five (71%) of seven plain wrens (Cantorchilus modestus) sampled from Costa Rica were positive for a new species of Isospora. Oocysts have a thin, smooth, double, colorless wall and measure 20.1 ± 1.4 × 23.4 ± 1.5 μm (18-24 × 20-26 μm) with an average length-width ratio of 1.2 μm. Sporocysts are ovoid, measure 9.5 ± 0.9 × 15.5 ± 1.1 μm (7-12 × 12-18 μm) with an average length-width ratio of 1.6 μm. A nipple-like steida body continuous with the sporocyst wall and a prominent oval-shaped substeida body are present. In addition to the four sporozoites, a single compact sporocyst residuum was present in each sporocyst. This is the first description of an Isospora species from the family Troglodytidae and the first report of Isospora from the rufous-and-white wren and plain wren.

• Trypanosoma cruzi and Chagas' Disease in the United States.

  Authors: Caryn Bern, Sonia Kjos, Michael J Yabsley, Susan P Montgomery

  Clinical microbiology reviews. 10/2011; 24(4):655-81.

  Chagas' disease is caused by the protozoan parasite Trypanosoma cruzi and causes potentially life-threatening disease of the heart and gastrointestinal tract. The southern half of the United StatesChagas' disease is caused by the protozoan parasite Trypanosoma cruzi and causes potentially life-threatening disease of the heart and gastrointestinal tract. The southern half of the United States contains enzootic cycles of T. cruzi, involving 11 recognized triatomine vector species. The greatest vector diversity and density occur in the western United States, where woodrats are the most common reservoir; other rodents, raccoons, skunks, and coyotes are also infected with T. cruzi. In the eastern United States, the prevalence of T. cruzi is highest in raccoons, opossums, armadillos, and skunks. A total of 7 autochthonous vector-borne human infections have been reported in Texas, California, Tennessee, and Louisiana; many others are thought to go unrecognized. Nevertheless, most T. cruzi-infected individuals in the United States are immigrants from areas of endemicity in Latin America. Seven transfusion-associated and 6 organ donor-derived T. cruzi infections have been documented in the United States and Canada. As improved control of vector- and blood-borne T. cruzi transmission decreases the burden in countries where the disease is historically endemic and imported Chagas' disease is increasingly recognized outside Latin America, the United States can play an important role in addressing the altered epidemiology of Chagas' disease in the 21st century.

• Infection prevalences of common tick-borne pathogens in adult lone star ticks (Amblyomma americanum) and American dog ticks (Dermacentor variabilis) in Kentucky.

  Authors: Charissa M Fritzen, Junjun Huang, Kathleen Westby, James D Freye, Brett Dunlap, Michael J Yabsley, Mike Schardein, John R Dunn, Timothy F Jones, Abelardo C Moncayo

  The American journal of tropical medicine and hygiene. 10/2011; 85(4):718-23.

  Rocky Mountain spotted fever, Lyme disease, and ehrlichiosis are tick-borne diseases that are reported annually in Kentucky. We conducted a survey to describe infection prevalence of tick-borneRocky Mountain spotted fever, Lyme disease, and ehrlichiosis are tick-borne diseases that are reported annually in Kentucky. We conducted a survey to describe infection prevalence of tick-borne pathogens in Amblyomma americanum and Dermacentor variabilis ticks collected in Kentucky. During 2007-2008, we collected 287 ticks (179 D. variabilis and 108 A. americanum) from canine, feral hog, horse, raccoon, white-tailed deer, and human hosts in six counties in Kentucky. Ticks were screened for Rickettsia spp., Borrelia spp., and Ehrlichia spp. by using polymerase chain reaction. Forty-one (14.3%) ticks (31 A. americanum and 10 D. variabilis) were polymerase chain reaction-positive for a Rickettsia spp. Fourteen (4.9%) ticks (6 A. americanum and 8 D. variabilis) were positive for E. chaffeensis, and 4 A. americanum (1.4%) were positive for E. ewingii. One (0.4%) A. americanum was positive for Borrelia lonestari. Although Rocky Mountain spotted fever is diagnosed in Kentucky, no R. rickettsii was found in ticks in this study.

• A new isospora species of passerines in the family turdidae from costa rica.

  Authors: Shamus P Keeler, Michael J Yabsley, Samantha E J Gibbs, Sabrina N McGraw, Sonia M Hernandez

  The Journal of parasitology. 09/2011; 98(1):167-9.

  abstract :  Seven thrush species (Turdidae) from Costa Rica were examined for intestinal parasites; 21 of the 84 (25%) birds sampled were positive for a new species of Isospora . Oocysts of Isosporaabstract :  Seven thrush species (Turdidae) from Costa Rica were examined for intestinal parasites; 21 of the 84 (25%) birds sampled were positive for a new species of Isospora . Oocysts of Isospora zorzali n. sp. have thin, smooth, double, and colorless walls; they measure 19.7 ± 1.5 µm × 18.6 ± 1.4 µm (16-24 µm × 15-21 µm), with an average length-width ratio of 1.1 µm. Sporocysts are ovoid, measure 8.5 ± 1.1 µm × 14.5 ± 1.7 µm (7-11 µm × 11-18 µm) with an average length-width ratio of 1.7 µm. A nipple-like stieda body continuous with the sporocyst wall is present, but no substieda body was observed. A sporocyst residuum consisting of large equal sized granules was observed either clumped together or diffusely. The sporocysts fill the entire oocysts with little to no open space observed. This is the first report of Isospora species from any of the sampled host species and also the first report from any species of thrush in Costa Rica.

• Novel relapsing fever Borrelia detected in African penguins (Spheniscus demersus) admitted to two rehabilitation centers in South Africa.

  Authors: Michael J Yabsley, Nola J Parsons, Elizabeth C Horne, Barbara C Shock, Michaelle Purdee

  Parasitology research. 08/2011; 110(3):1125-30.

  The African penguin, Spheniscus demersus, the only penguin species that breeds in Africa, is endangered, and several diseases including avian malaria, babesiosis, and aspergillosis are common in someThe African penguin, Spheniscus demersus, the only penguin species that breeds in Africa, is endangered, and several diseases including avian malaria, babesiosis, and aspergillosis are common in some populations. From 2002 to 2010, spirochetes morphologically consistent with Borrelia were observed on thin blood smears from 115 of 8,343 (1.4%) African penguins admitted to rehabilitation centers in the Western Cape and Eastern Cape provinces of South Africa. Prevalence rates were significantly higher among chicks and juveniles compared with adults and for birds sampled during the summer months of October to February compared with winter months. The majority of infected birds were ultimately released, despite lack of antibiotic treatment; however, at least one bird is believed to have died of borreliosis based on characteristic gross and microscopic lesions. Analysis of partial flaB gene sequences indicated this was a relapsing fever Borrelia most similar to a Borrelia sp. detected in soft ticks from a seabird colony in Japan. This represents the fourth report of a relapsing fever Borrelia sp. in an avian species and highlights the need for additional studies of potentially pathogenic organisms infecting the African penguin in South Africa.

• Prevalence to Toxoplasma gondii and Sarcocystis spp. in a reintroduced fisher (Martes pennanti) population in Pennsylvania.

  Authors: Jeffery L Larkin, Mourad Gabriel, Richard W Gerhold, Michael J Yabsley, Jennifer Christine Wester, Jan G Humphreys, Robert Beckstead, J P Dubey

  The Journal of parasitology. 06/2011; 97(3):425-9.

  Understanding the role of disease in population regulation is important to the conservation of wildlife. We evaluated the prevalence of Toxoplasma gondii exposure and Sarcocystis spp. infection in 46Understanding the role of disease in population regulation is important to the conservation of wildlife. We evaluated the prevalence of Toxoplasma gondii exposure and Sarcocystis spp. infection in 46 road-killed and accidentally trapper-killed fisher (Martes pennanti) carcasses collected and stored at -20 C by the Pennsylvania Game Commission from February 2002 to October 2008. Blood samples were assayed for T. gondii antibodies using the modified agglutination test (MAT, 1 : 25) and an indirect immunofluorescent antibody test (IFAT, 1 : 128). For genetic analysis, DNA samples were extracted from thoracic and pelvic limb skeletal muscle from each carcass to test for Sarcocystis spp. using 18s-rRNA PCR primers. Antibodies to T. gondii were found in 100% (38 of 38) of the fishers tested by MAT and in 71% (32 of 45) of the fishers tested by IFAT. PCR analysis revealed that 83% (38 of 46) of the fishers were positive for Sarcocystis spp. Sequence analysis of 7 randomly chosen amplicons revealed the fisher sarcocysts had a 98.3% to 99.1% identity to several avian Sarcocystis spp. sequences in GenBank. Data from our study suggest that a high percentage of fishers in Pennsylvania have been exposed to T. gondii and are infected with Sarcocystis spp.

• Serological response of cats to experimental Besnoitia darlingi and Besnoitia neotomofelis infections and prevalence of antibodies to these parasites in cats from Virginia and Pennsylvania.

  Authors: Alice E Houk, Alexa C Rosypal, David C Grant, J P Dubey, Anne M Zajac, Michael J Yabsley, David S Lindsay

  The Journal of parasitology. 04/2011; 97(2):259-61.

  Besnoitia darlingi and Besnoitia neotomofelis are cyst-forming tissue apicomplexan parasites that use domestic cats (Felis domesticus) as definitive hosts and opossums (Didelphis virginiana ) andBesnoitia darlingi and Besnoitia neotomofelis are cyst-forming tissue apicomplexan parasites that use domestic cats (Felis domesticus) as definitive hosts and opossums (Didelphis virginiana ) and Southern Plains woodrats (Neotoma micropus) as intermediate hosts, respectively. Nothing is known about the prevalence of B. darlingi or B. neotomofelis in cats from the United States. Besnoitia darlingi infections have been reported in naturally infected opossums from many states in the United States, and B. neotomofelis infections have been reported from Southern Plains woodrats from Texas, but naturally infected cats have not been identified. The present study examined the IgG antibody response of cats to experimental infection (B. darlingi n  =  1 cat; B. neotomofelis n  =  3 cats). Samples from these cats were used to develop an indirect immunofluorescent antibody test (IFAT), which was then used to examine seroprevalence of IgG antibodies to tachyzoites of B. darlingi and B. neotomofelis in a population of domestic cats from Virginia (N  =  232 cats) and Pennsylvania (N  =  209). The serum from cats inoculated with B. darlingi or B. neotomofelis cross-reacted with each other's tachyzoites. The titers to heterologous tachyzoites were 1 to 3 dilutions lower than to homologous tachyzoites. Sera from B. darlingi- or B. neotomofelis-infected cats did not react with tachyzoites of Toxoplasma gondii or Neospora caninum or merozoites of Sarcocystis neurona using the IFAT. Antibodies to B. darlingi were found in 14% and 2% of cats from Virginia and Pennsylvania, respectively. Antibodies to B. neotomofelis were found in 5% and 4% of cats from Virginia and Pennsylvania, respectively. Nine cats from Virginia and 1 cat from Pennsylvania were positive for both.

• Experimental primary and secondary infections of domestic dogs with Ehrlichia ewingii.

  Authors: Michael J Yabsley, Dustin S Adams, Thomas P O'Connor, Ramaswamy Chandrashekar, Susan E Little

  Veterinary microbiology. 02/2011; 150(3-4):315-21.

  In this study, the infection dynamics of Ehrlichia ewingii, causative agent of granulocytotropic ehrlichiosis in dogs and humans, was examined in experimentally infected dogs by using a combinationIn this study, the infection dynamics of Ehrlichia ewingii, causative agent of granulocytotropic ehrlichiosis in dogs and humans, was examined in experimentally infected dogs by using a combination of physical examination, hematologic and biochemical analyses, and molecular and serologic assays. For the experimental trials, blood from an E. ewingii-infected dog was inoculated intravenously into two naïve dogs and two dogs with prior experimental exposure to E. ewingii (both were negative for E. ewingii DNA by polymerase chain reaction (PCR) assay, but seropositive from initial infection 8 and 10 months prior to challenge). A negative control dog was inoculated with blood from a negative dog. The two primary infection dogs were positive for E. ewingii DNA on DPI 4, remained consistently positive until DPI 60, and were intermittently positive until the end of the study (DPI 144). The two primary infection dogs developed antibodies reactive to E. ewingii by DPI 28 and remained seropositive for the duration of the study. Primary infected dogs had intermittent fever, thrombocytopenia, and leukopenia and some dogs were hyperphosphatemic and/or had elevated ALP levels. The two challenge dogs were positive for E. ewingii DNA on DPI 4 and 18, which was similar to the primary infection dogs, but the duration of E. ewingii DNA detection was shorter. Also, the two challenged dogs did not develop pyrexia or show any hematologic or biochemical abnormalities. E. ewingii was successfully transmitted between dogs by Amblyomma americanum, but not Rhipicephalus sanguineus. This study provides data on the infection dynamics of E. ewingii in dogs during primary and challenge infections and suggests that prior exposure may lessen clinical disease during subsequent infections.

• Influenza-A viruses in ducks in northwestern Minnesota: fine scale spatial and temporal variation in prevalence and subtype diversity.

  Authors: Benjamin R Wilcox, Gregory A Knutsen, James Berdeen, Virginia Goekjian, Rebecca Poulson, Sagar Goyal, Srinand Sreevatsan, Carol Cardona, Roy D Berghaus, David E Swayne, Michael J Yabsley, David E Stallknecht

  PloS one. 01/2011; 6(9):e24010.

  Waterfowl from northwestern Minnesota were sampled by cloacal swabbing for Avian Influenza Virus (AIV) from July-October in 2007 and 2008. AIV was detected in 222 (9.1%) of 2,441 ducks in 2007 and inWaterfowl from northwestern Minnesota were sampled by cloacal swabbing for Avian Influenza Virus (AIV) from July-October in 2007 and 2008. AIV was detected in 222 (9.1%) of 2,441 ducks in 2007 and in 438 (17.9%) of 2,452 ducks in 2008. Prevalence of AIV peaked in late summer. We detected 27 AIV subtypes during 2007 and 31 during 2008. Ten hemagglutinin (HA) subtypes were detected each year (i.e., H1, 3-8, and 10-12 during 2007; H1-8, 10 and 11 during 2008). All neuraminidase (NA) subtypes were detected during each year of the study. Subtype diversity varied between years and increased with prevalence into September. Predominant subtypes during 2007 (comprising ≥5% of subtype diversity) included H1N1, H3N6, H3N8, H4N6, H7N3, H10N7, and H11N9. Predominant subtypes during 2008 included H3N6, H3N8, H4N6, H4N8, H6N1, and H10N7. Additionally, within each HA subtype, the same predominant HA/NA subtype combinations were detected each year and included H1N1, H3N8, H4N6, H5N2, H6N1, H7N3, H8N4, H10N7, and H11N9. The H2N3 and H12N5 viruses also predominated within the H2 and H12 subtypes, respectively, but only were detected during a single year (H2 and H12 viruses were not detected during 2007 and 2008, respectively). Mallards were the predominant species sampled (63.7% of the total), and 531 AIV were isolated from this species (80.5% of the total isolates). Mallard data collected during both years adequately described the observed temporal and spatial prevalence from the total sample and also adequately represented subtype diversity. Juvenile mallards also were adequate in describing the temporal and spatial prevalence of AIV as well as subtype diversity.

• Distribution, prevalence, and genetic characterization of Baylisascaris procyonis in selected areas of Georgia.

  Authors: Emily L Blizzard, Cheryl D Davis, Scott Henke, David B Long, Christopher A Hall, Michael J Yabsley

  The Journal of parasitology. 12/2010; 96(6):1128-33.

  Baylisascaris procyonis is an intestinal nematode of raccoons (Procyon lotor) that can cause fatal larval migrans in numerous species of birds and mammals, including humans. Although this parasiteBaylisascaris procyonis is an intestinal nematode of raccoons (Procyon lotor) that can cause fatal larval migrans in numerous species of birds and mammals, including humans. Although this parasite has historically been absent in the southeastern United States, it has been found in isolated regions in the Appalachian Mountains and was recently documented in DeKalb County, Georgia. The first objective of the current study was to investigate the distribution and prevalence of B. procyonis in selected populations of raccoons in Georgia. Intestinal tracts of 312 raccoons from 25 Georgia counties were examined for B. procyonis. The only county where B. procyonis was detected was Clarke County, where 12 of 116 (10.3%) raccoons were infected. In Clarke County, significantly more juveniles (P  =  0.049) were infected compared with adults, and no differences in prevalence were noted by sex, season of capture, or land use (rural vs. urban); however, significantly (P  =  0.0370) higher worm burdens were found in infected raccoons from urban/suburban locations compared with rural areas. In addition, Toxascaris leonina , a morphologically similar ascarid, was found in 3 raccoons from Clarke County (n  =  2) and Morgan County (n  =  1). A second objective was to determine if sequence polymorphisms were associated with B. procyonis from different geographic regions. Because sequences from a single worm from Japan had been entered into GenBank, we obtained nematodes from Kentucky and Texas for comparison with our samples from Georgia. Sequence analysis of the 18S and 5.8S rRNA genes and the internal transcribed spacer (ITS) -1 and ITS-2 regions confirmed Georgia samples were B. procyonis. Although several polymorphic bases were observed within both ITS regions, none was associated with a particular geographic location. These data indicate that the distribution of B. procyonis within Georgia is increasing and only limited genetic variation is present in the rRNA and ITS gene regions among B. procyonis from the southern United States and introduced populations in Japan.

• Geographic expansion of Baylisascaris procyonis roundworms, Florida, USA.

  Authors: Emily L Blizzard, Michael J Yabsley, Margaret F Beck, Stefan Harsch

  Emerging infectious diseases. 11/2010; 16(11):1803-4.

  To the Editor: Baylisascaris procyonis roundworms are common parasites of raccoons (Procyon lotor) in several regions of North America, Europe, and Asia. These parasites are increasingly recognizedTo the Editor: Baylisascaris procyonis roundworms are common parasites of raccoons (Procyon lotor) in several regions of North America, Europe, and Asia. These parasites are increasingly recognized as a cause of larva migrans in humans, an infection that often results in severe neurologic sequelae or death. In addition, larva migrans has been documented in ?90 species of wild and domestic birds and mammals. In the United States, B. procyonis roundworms are most prevalent in the midwestern, northeastern, and Pacific western states. Numerous surveillance studies have been conducted in the southeastern United States, and B. procyonis roundworms are most common in the mountainous regions of Virginia, Kentucky, and West Virginia (1-4). Geographic expansion of B. procyonis roundworms has been recently documented in Georgia. In 2002, 22% of raccoons sampled in DeKalb County, Georgia, a highly urbanized area near Atlanta, were positive for the parasite (5), and recently, 10% of raccoons sampled in Clarke County, Georgia, were positive (6). Whether this expansion is due to natural spread of the parasite among raccoons or to translocations of infected raccoons into naive areas is unclear. We document expansion of B. procyonis roundworms into northwestern and southeastern Florida.

• Evaluation of peptide- and recombinant protein-based assays for detection of anti-Ehrlichia ewingii antibodies in experimentally and naturally infected dogs. [corrected]

  Authors: Thomas P O'Connor, Jill M Saucier, Daryn Daniluk, Brett A Stillman, Regis Krah, Yasuko Rikihisa, Qingming Xiong, Michael J Yabsley, Dustin S Adams, Pedro Paulo V P Diniz, Edward B Breitschwerdt, Stephen D Gaunt, Ramaswamy Chandrashekar

  American journal of veterinary research. 10/2010; 71(10):1195-200.

  To evaluate microtiter-plate format ELISAs constructed by use of different diagnostic targets derived from the Ehrlichia ewingii p28 outer membrane protein for detection of E ewingii antibodies inTo evaluate microtiter-plate format ELISAs constructed by use of different diagnostic targets derived from the Ehrlichia ewingii p28 outer membrane protein for detection of E ewingii antibodies in experimentally and naturally infected dogs. Serum samples from 87 kenneled dogs, 9 dogs experimentally infected with anti-E ewingii, and 180 potentially naturally exposed dogs from Missouri. The capacities of the synthetic peptide and truncated recombinant protein to function as detection reagents in ELISAs were compared by use of PCR assay, western blot analysis, and a full-length recombinant protein ELISA. Diagnostic targets included an E ewingii synthetic peptide (EESP) and 2 recombinant proteins: a full-length E ewingii outer membrane protein (EEp28) and a truncated E ewingii outer membrane protein (EETp28) A subset of Ehrlichia canis-positive samples cross-reacted in the EEp28 ELISA; none were reactive in the EESP and EETp28 ELISAs. The EESP- and EETp28-based ELISAs detected E ewingii seroconversion at approximately the same time after infection as the EEp28 ELISAs. In afield population, each of the ELISAs identified the same 35 samples as reactive and 27 samples as nonreactive. Anaplasma and E can is peptides used in a commercially available ELISA platform did not detect anti-E ewingii antibodies in experimentally infected dogs. The EESP and EETp28 ELISAs were suitable for specifically detecting anti-E ewingii antibodies in experimentally and naturally infected dogs.

• Distribution and prevalence of Cytauxzoon felis in bobcats (Lynx rufus), the natural reservoir, and other wild felids in thirteen states.

  Authors: Barbara C Shock, Staci M Murphy, Laura L Patton, Philip M Shock, Colleen Olfenbuttel, Jeff Beringer, Suzanne Prange, Daniel M Grove, Matt Peek, Joseph W Butfiloski, Daymond W Hughes, J Mitchell Lockhart, Sarah N Bevins, Sue VandeWoude, Kevin R Crooks, Victor F Nettles, Holly M Brown, David S Peterson, Michael J Yabsley

  Veterinary parasitology. 10/2010; 175(3-4):325-30.

  Cytauxzoon felis, a protozoan parasite of wild and domestic felids, is the causative agent of cytauxzoonosis in domestic and some exotic felids in the United States. The bobcat (Lynx rufus) is theCytauxzoon felis, a protozoan parasite of wild and domestic felids, is the causative agent of cytauxzoonosis in domestic and some exotic felids in the United States. The bobcat (Lynx rufus) is the natural reservoir for this parasite, but other felids such as Florida panthers (Puma concolor coryii) and domestic cats may maintain long-term parasitemias and serve as reservoirs. Experimentally, two tick species, Dermacentor variabilis and Amblyomma americanum, have demonstrated the ability to transmit C. felis. These two tick species have overlapping distributions throughout much of the southeastern United States. The objective of the current study was to determine the distribution and prevalence of C. felis in free-ranging bobcat populations from 13 states including California, Colorado, Florida, Georgia, Kansas, Kentucky, Missouri, North Carolina, North Dakota, Ohio, Oklahoma, South Carolina, and West Virginia. These states were selected because of differential vector presence; D. variabilis is present in each of these states except for the region of Colorado sampled and A. americanum is currently known to be present only in a subset of these states. Blood or spleen samples from 696 bobcats were tested for C. felis infection by a polymerase chain reaction (PCR) assay which targeted the first ribosomal internal transcribed spacer region (ITS-1). Significantly higher prevalences of C. felis were detected from Missouri (79%, n=39), North Carolina (63%, n=8), Oklahoma (60%, n=20), South Carolina (57%, n=7), Kentucky (55%, n=74), Florida (44%, n=45), and Kansas (27%, n=41) compared with Georgia (9%, n=159), North Dakota (2.4%, n=124), Ohio (0%, n=19), West Virginia (0%, n=37), California (0%, n=26), and Colorado (0%, n=67). In addition to bobcats, seven cougars (Puma concolor) from Georgia, Louisiana, and North Dakota and one serval (Leptailurus serval) from Louisiana were tested for C. felis. Only one cougar from Louisiana was PCR positive, which represents the first report of an infected cougar outside of the Florida panther population. These data also indicate that C. felis is present in North Dakota where infection has not been reported in domestic cats. Based on a nonparametric analysis, prevalence rates were significantly higher in states where there are established populations of A. americanum, which supports recent data on the experimental transmission of C. felis by A. americanum and the fact that domestic cat clinical cases are temporally associated with A. americanum activity. Collectively, these data confirm that bobcats are a common reservoir for C. felis and that A. americanum is likely an epidemiologically important vector.

• Absence of Rickettsia rickettsii and occurrence of other spotted fever group rickettsiae in ticks from Tennessee.

  Authors: Abelardo C Moncayo, Sara B Cohen, Charissa M Fritzen, Eileen Huang, Michael J Yabsley, James D Freye, Brett G Dunlap, Junjun Huang, Daniel G Mead, Timothy F Jones, John R Dunn

  The American journal of tropical medicine and hygiene. 09/2010; 83(3):653-7.

  Rocky Mountain spotted fever (RMSF) is the most common tick-borne illness in Tennessee. Little is known about the occurrence of R. rickettsii, the causative agent, in ticks in Tennessee. To betterRocky Mountain spotted fever (RMSF) is the most common tick-borne illness in Tennessee. Little is known about the occurrence of R. rickettsii, the causative agent, in ticks in Tennessee. To better understand the prevalence and distribution of rickettsial agents in ticks, we tested 1,265 Amblyomma, Dermacentor, and Ixodes adult and nymphal ticks. Additionally, we tested 231 Amblyomma americanum larvae. Ticks were collected from 49 counties from humans, wild animals, domestic canines, and flannel drags. Spotted fever group rickettsiae (SFGR) DNA was detected by polymerase chain reaction (PCR) in 32% of adult and nymphal ticks. A total minimum infection rate of 85.63 was found in larval pools tested. Three rickettsial species, Rickettsia montana, Rickettsia amblyommii, and Rickettsia cooleyi were identified by molecular analysis. Rickettsia rickettsii was not detected. This study suggests that some RMSF cases reported in Tennessee may be caused by cross-reactivity with other SFGR antigenically related to R. rickettsii.

• Infectivity, pathogenicity, and virulence of Trypanosoma cruzi Isolates from sylvatic animals and vectors, and domestic dogs from the United States in ICR strain mice and SD strain rats.

  Authors: Dawn M Roellig, Michael J Yabsley

  The American journal of tropical medicine and hygiene. 09/2010; 83(3):519-22.

  Trypanosoma cruzi, the causative agent of Chagas disease, is widespread in the southern United States. In addition to detection in numerous wildlife host species, cases have been diagnosed inTrypanosoma cruzi, the causative agent of Chagas disease, is widespread in the southern United States. In addition to detection in numerous wildlife host species, cases have been diagnosed in domestic dogs and humans. In the current investigation, groups of laboratory mice [Crl:CD1 (ICR)] were inoculated with one of 18 United States T. cruzi isolates obtained from a wide host range to elucidate their infectivity, pathogenicity, and virulence. In addition, laboratory rats (SD strain) were inoculated with four isolates. Mice and rats were susceptible to infection with all strains, but no morbidity or mortality was noted, which indicates that these T. cruzi isolates from the United States had low virulence for laboratory mice and rats.

• Aelurostrongylus abstrusus larvae in the colon of two cats.

  Authors: Angela E Ellis, Cathy A Brown, Michael J Yabsley

  Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc. 07/2010; 22(4):652-5.

  A 12-year-old male domestic shorthair cat with a history of depression, aggression, and fever was presented for necropsy, and formalin-fixed tissues from a second male domestic shorthair cat ofA 12-year-old male domestic shorthair cat with a history of depression, aggression, and fever was presented for necropsy, and formalin-fixed tissues from a second male domestic shorthair cat of unknown age were submitted for histopathologic examination to the Athens Veterinary Diagnostic Laboratory. Both cats had granulomatous pneumonia associated with large numbers of parasite eggs and larvae, consistent with Aelurostrongylus abstrusus. Both cats also had larvae within glands in the colon that were identified morphologically as A. abstrusus first-stage larvae.

• Clinical challenge.

  Authors: Barbara C Shock, Jason W Brooks, Esteban Pokorny, Terry Mattive, Michael J Yabsley

  Journal of zoo and wildlife medicine : official publication of the American Association of Zoo Veterinarians. 06/2010; 41(2):374-6.

• Factors associated with Trypanosoma cruzi exposure among domestic canines in Tennessee.

  Authors: Meghan E Rowland, Jenny Maloney, Sara Cohen, Michael J Yabsley, Junjun Huang, Melissa Kranz, Alice Green, John R Dunn, L Rand Carpenter, Timothy F Jones, Abelardo C Moncayo

  The Journal of parasitology. 06/2010; 96(3):547-51.

  Trypanosoma cruzi , the etiologic agent of Chagas' disease, is enzootic in animal populations of the southeastern United States. In the United States, T. cruzi prevalence has been reported for overTrypanosoma cruzi , the etiologic agent of Chagas' disease, is enzootic in animal populations of the southeastern United States. In the United States, T. cruzi prevalence has been reported for over 20 different wildlife species, and 7 autochthonous human cases have been documented since 1955. Previous canine (Canis familiaris) serosurveys have been limited either by small sample size or confined geographic reporting areas. In this study, we report a seroprevalence of 6.4% among 860 canines from 31 counties and 5 ecoregions throughout Tennessee, using an indirect immunofluorescent assay (IFA). Statistically significant associations between seropositivity and age, weight, and outdoor living were noted. Differences in seropositivity were not seen based on American Kennel Club (AKC) group, sex, habitat, land cover, and ecoregion. Greater attention should be given to possible T. cruzi transmission in Tennessee and veterinarians should consider Chagas' disease as a differential diagnosis with compatible signs.