Heterobilharzia americana infection in a Grant's zebra (Equus burchelli boehmi).

Heterobilharzia americana is a trematode parasite (family: Schistosomatidae) of mammalian wildlife that occasionally infects domestic dogs and horses in the southeastern United States. This report presents the first case of H. americana infection in a Grant's zebra (Equus burchelli boehmi). The parasite was diagnosed post mortem as an incidental finding by histopathologic identification of H. americana eggs in the liver parenchyma after the zebra succumbed in an accidental traumatic death. Molecular analysis of a portion of the parasite small subunit ribosomal RNA gene demonstrated 100% identity with DNA sequences from parasites previously characterized in domestic horses. Equine infections with H. americana are considered uncommon, but are probably underdiagnosed.

Enantioselective total synthesis and biological evaluation of (-)-solanacol.

An enantioselective synthesis of the phenyl ring-containing strioglactone, (-)-solanocol, is described. Application of a Dynamic Kinetic Resolution (DKR) in the stereo-defining step enabled a step-economical synthesis to be achieved, and allowed access to natural and non-natural enantiomers with equal facility. Results of seed germination assays and Differential Scanning Fluorimetry (DSF) measurements with the known strigolactone receptor protein, Decreased Apical Dominance 2 (DAD2), are reported.

Trypanosoma cruzi discrete typing unit TcIV implicated in a case of acute disseminated canine Chagas disease.

In 2006, Nabity et al. reported on an atypical presentation of Trypanosoma cruzi (T. cruzi) infection in an 8-month old English Mastiff from central Texas. Clinical signs and laboratory findings included lymphadenopathy, weight loss, amastigotes in lymph node aspirates, and initial serological results suggestive of either T. cruzi or Leishmania infection. Given the poor prognosis, the dog was euthanized and subsequent testing and culture of parasites from a lymph node revealed T. cruzi infection. Because different parasite discrete typing units (DTUs) are potentially associated with different disease outcomes in a variety of mammalian hosts, an understanding of these relationships in naturally infected dogs may be useful for informing canine prognosis and may also have human health implications. Here, we compared strains using culture versus culture-independent methods. We subjected archived cultured parasites harvested from the lymph node in the infected Mastiff to two independent approaches for determining parasite DTU, including sequencing of the TcSC5D gene and use of DTU-specific qPCR probes to hybridize the nuclear spliced leader intergenic region (SL-IR). Both approaches revealed T. cruzi discrete typing unit TcIV. Testing of multiple other tissues directly without culturing, including heart/tongue, intestine, trachea/lymph nodes, and uterus/ovary, provided further evidence of disseminated TcIV infection in this dog. We report T. cruzi DTU TcIV as the cause of a severe disseminated infection in a dog from an area with triatomine vectors in central Texas, adding to the limited body of clinicopathologic data that links specific parasite strains to disease outcomes in dogs in the US. Future studies to type parasites from asymptomatic dogs and those with diverse disease manifestations will be useful in informing the degree to which parasite genetics is associated with disease presentation and severity. If applied to antemortem samples, diagnostic typing of parasites from infected dogs may assist in determining prognosis.

Microsporidia - Emergent Pathogens in the Global Food Chain.

Intensification of food production has the potential to drive increased disease prevalence in food plants and animals. Microsporidia are diversely distributed, opportunistic, and density-dependent parasites infecting hosts from almost all known animal taxa. They are frequent in highly managed aquatic and terrestrial hosts, many of which are vulnerable to epizootics, and all of which are crucial for the stability of the animal-human food chain. Mass rearing and changes in global climate may exacerbate disease and more efficient transmission of parasites in stressed or immune-deficient hosts. Further, human microsporidiosis appears to be adventitious and primarily associated with an increasing community of immune-deficient individuals. Taken together, strong evidence exists for an increasing prevalence of microsporidiosis in animals and humans, and for sharing of pathogens across hosts and biomes.

Heterobilharzia americana infection and congestive heart failure in a llama (Lama glama).

The schistosome Heterobilharzia americana infects several mammalian species in the southeastern United States, including horses, but infections have not been reported in camelids. This is a report of H. americana infection in a 6-year-old llama with extensive cardiac pathology and congestive heart failure. Parasite-induced granulomas were widely disseminated and included overwhelming involvement of the lungs and liver. Microscopic lesions in the heart included myofiber degeneration and necrosis, with extensive replacement fibrosis. Polymerase chain reaction amplification and sequencing confirmed the presence of H. americana in the lungs.

Distribution and characterization of Heterobilharzia americana in dogs in Texas.

Heterobilharzia americana is a trematode parasite (family Schistosomatidae) that infects a wide range of wild mammalian hosts. Canine cases have been reported in the Gulf coast and south Atlantic states, Kansas, and Oklahoma. A total of 238 canine H. americana cases in Texas were retrospectively collected for a period of approximately 22 years from case records at the Texas Veterinary Medical Diagnostic Laboratory and the Veterinary Medical Teaching Hospital pathology service, diagnostic parasitology service, and Gastrointestinal Laboratory at Texas A&M University College of Veterinary Medicine. Of these cases, 26 patients had 1-2 repeat positive tests for a total of 268 positive tests (26 biopsies, 39 necropsies, 160 fecal examinations, and 43 PCR). Multiple dogs were infected in 12 households. Cases were distributed primarily in the eastern region of Texas in 42 of 254 counties. Cases were seen as far west as Kerr county and in counties bordering Oklahoma, Louisiana, Mexico, and the Gulf of Mexico. The median dog age was 5.6 years (2.7 months to 17.2 years) and the median weight was 20.5 kg (1-61.6 kg). All American Kennel Club (AKC) breed groups were represented (n=186): crossbred (20%), herding (17.8%), sporting (16.1%), toy (10.8%), hounds (10.8%), working (10.1%), terrier (8.5%), non-sporting (4.9%), and miscellaneous (1%). No seasonal pattern of diagnosis was apparent. Clinical signs reported (n=90) were diarrhea (67%), weight loss (38%), anorexia/hyporexia (27%), vomiting (22%), hematochezia (20%), lethargy (17%), polyuria/polydipsia (6%), and collapse (3%). In 39 necropsy cases, trematode eggs were identified by histopathology in the small intestine (84%), liver (84%), large intestine (39%), pancreas (35%), lung (9%), lymph node (8%), spleen (4%), and stomach (3%). Adult parasites were identified histologically in four cases. Granulomatous inflammation associated with the eggs was the most commonly reported histopathologic change. Other changes reported were fibrosis, pigment in macrophages, and organ mineralization. Glomerulonephritis was identified in four cases. Of 20 necropsy cases where death was attributable to H. americana infection, only one case was diagnosed ante mortem. Eleven of these dogs were examined by a veterinarian but H. americana was included as a differential diagnosis in only two cases. Reported differential diagnoses included ethylene glycol toxicity, cholecalciferol toxicity, lymphoma, and pancreatitis. These data indicate that this parasite is more widely distributed and more common than is generally recognized. Increased awareness may aid in more diagnoses and timely therapy.

Detraining decreases Hb(mass) of triathletes.

Haemoglobin mass (Hbmass) determination using CO rebreathing may assist to detect illegal blood doping practices, however variations in Hbmass with periods of intensive training and detraining must be quantified. This study aimed to determine the effect of a 30-day period of detraining on Hbmass in ultra-endurance triathletes. 9 male recreational triathletes (29-44 years) participated in the study. Hbmass was assessed using CO rebreathing 30 days and 10 days before an ultra-endurance triathlon and after ~10, 20 and 30 days of detraining following the race. V˙O2max was assessed 10 days before the race and also after the 30-day detraining period, which consisted of an 87% reduction in training hours. After 30-days of detraining there was a 3.1% decrease in mean Hbmass from 868±99 to 840±94 g, (p=0.03), and a 4.7% decrease in mean V˙O2max from 4.83±0.29 to 4.61±0.41 L/min as well as a 2.8% increase of body mass from 75.1±6.4 to 77.1±6.1 kg and a 28% increase in skinfold total from 43.9±14.2 to 55.1±14.0 mm. Individual decreases in Hbmass following detraining would need to be considered if using Hbmass for anti-doping purposes.

Natural Heterobilharzia americana infection in horses in Texas.

The schistosome Heterobilharzia americana infects dogs, raccoons, and other mammals in the southeastern United States. Migration of eggs into the liver results in parasitic granulomas with varying degrees of fibrosis and inflammation. Recently, hepatic parasitic granulomas in horses were shown to be caused by H. americana infection. In the present study, samples of liver from 11 of 12 horses with hepatic granulomas identified at necropsy (n = 11) or surgical biopsy (n = 1) were used for DNA extraction, polymerase chain reaction amplification and sequencing using primers specific for a portion of the H. americana small subunit ribosomal RNA gene. A polymerase chain reaction amplicon of the correct size was produced from the extracted DNA in 8 of the 11 horses. Amplicons from 5 of the 8 positive horses were sequenced and had 100% identity with H. americana. In all but 2 of the 12 horses, Heterobilharzia was not responsible for the primary clinical disease, and the hepatic granulomas were considered an incidental finding.

No change in hemoglobin mass after 40 days of physical activity in previously untrained adults.

A high hemoglobin mass (Hb(mass)) is associated with a high maximum aerobic power (VO(2max)), however, the extent to which Hb(mass) is influenced by training is currently unclear. Accordingly, this study monitored changes in Hb(mass) and VO(2max) in 12 previously untrained adults (aged 18-25 years) following 40 days of regular physical activity. Hb(mass) and VO(2max) were assessed at the start and end of a 40-day physical activity program, which comprised of approximately 40 min of daily, moderate-intensity physical activity. Relative VO(2max) increased by 11.3%, yet there was no significant change in relative Hb(mass) (1.7%) and body mass (0.2%) during the 40-day period. There was a significant correlation between Hb(mass) and VO(2max) at the start of the study (r=0.58, P=0.05), but not between the change in relative VO(2max) and the change in relative Hb(mass) (r=-0.07, P=0.83). Our results support the concept of relative stability in Hb(mass) with approximately 1 month of moderate-intensity physical activity suggesting that Hb(mass) may be used for talent identification and possibly for anti-doping purposes.

Eight cases of feline cutaneous leishmaniasis in Texas.

Leishmaniasis is a zoonotic disease caused by intracellular Leishmania protozoa that are transmitted by sandflies. The disease occurs in 3 forms: cutaneous, mucocutaneous, and visceral. Cutaneous leishmaniasis has been reported in cats in Europe and South America and in 1 cat from Texas. Leishmania mexicana is endemic in Texas and has been reported to cause cutaneous lesions in humans. This article describes the pathology of 8 biopsy cases of feline cutaneous leishmaniasis presented to the Texas Veterinary Medical Diagnostic Laboratory over a 3.5-year period. The median age of the cats was 3 years; each was presented with nodular, ulcerative lesions on the pinnae and less commonly on the muzzle and periorbital skin. Histologically, the lesions were nodular to diffuse histiocytic dermatitis with numerous amastigotes (2-4 µm) within macrophages and occasionally within the interstitium. Organisms were often contained within round, clear, intracellular vacuoles. In areas of necrosis, organisms were also free within the interstitium. The overlying epidermis was hyperkeratotic, hyperplastic, and often ulcerated. The organisms were not argyrophilic (Gomori methenamine silver), reacted poorly with periodic acid-Schiff reagent, and were inconsistently basophilic with Giemsa. Although not readily visible histologically, kinetoplasts were evident in amastigotes in cytologic preparations. The lesions were similar to those described for cutaneous L. mexicana infection in humans. In 5 of the 8 cats, Leishmania mexicana DNA was amplified from paraffin-embedded tissue by polymerase chain reaction and sequenced.

Population-based survey of taeniasis along the United States-Mexico border.

Taenia solium and T. saginata are zoonotic tapeworms of substantial medical and economic importance. Although human taeniasis is widely recognised as an endemic problem in Mexico, its presence in the United States is poorly understood. The first population-based study to estimate the prevalence of human infection with Taenia tapeworms along the Texas-Mexico border has recently been conducted. Households were interviewed in the Texan city of El Paso and in the neighbouring Ciudad Juárez, in Mexico. Faecal samples from household members were then checked for Taenia eggs by flotation and/or for Taenia copro-antigens in an ELISA. The overall prevalence of taeniasis in this border region was found to be 3% but, compared with the residents of Juárez, El Paso residents were 8.6-fold more likely to be tapeworm carriers. The interviews revealed some important differences between the two study sites, particularly the more frequent use of anthelminthic drugs on the Mexican side of the border. These findings have implications in terms of the planning of effective health-education campaigns to decrease the prevalence of taeniasis in the human populations along the Texas-Mexico border.

Distribution and characterization of canine Chagas disease in Texas.

Although acute and chronic cases of canine Chagas disease have been reported from multiple areas in the southern region of the United States, little data are available on current disease occurrence patterns in endemic areas. Therefore, a study to assess frequency, geographic distribution, signalment, and clinical spectrum of Chagas disease in domestic dogs from Texas was conducted. Serology, histopathology, and clinical case records from multiple institutions for the time period 1993-2007 were analyzed. A total of 537 serologically and/or histopathologically confirmed cases were documented. Cases were reported from 48 of 254 counties within Texas, covering all major geographic regions. Forty-eight dog breeds were represented among the cases, primarily in the sporting and working groups. In histopathologically confirmed cases, acute death occurred in 42%, approximately half of which were <1 year of age. Nearly all cases with histopathology data reported myocarditis (97.9%) and observation of Trypanosoma cruzi organisms (81.7%). Predominant clinical observations included enlarged heart, lethargy, anorexia, ascites, cardiac conduction disturbances, and respiratory difficulties. An increasing rate of serologic test submissions was noted over the study period, with an overall positive test prevalence of 20.3%. The study results provide strong evidence that an active canine Chagas disease transmission cycle is present throughout all ecoregions of Texas, affecting a broad range of dog breeds and age groups.

Fatal encephalitozoonosis in two koalas.

Two young koalas from a fauna park, recently out of the pouch and approximately 6 months old, were found dead with no previous clinical signs or gross lesions. On histopathological examination, large numbers of spores consistent with a microsporidian organism were present intracellularly within the small intestinal mucosa. Electron microscopy and polymerase chain reaction studies (sequencing the 5' end of the SSU RNA gene) identified the organism as Encephalitozoon intestinalis with 100% homology with those of previously reported human isolates. This is believed to be the first report of this organism in a marsupial.

An atypical case of Trypanosoma cruzi infection in a young English Mastiff.

A case of Trypanosoma cruzi infection in a young English Mastiff from Texas is presented. Clinical signs and laboratory findings included subcutaneous edema, lymphadenopathy, weight loss, and hypoalbuminemia. Cytology of a lymph node revealed numerous amastigotes. No trypomastigotes were observed in buffy coat preparation of peripheral blood, and on histologic evaluation, most organs contained numerous interstitial pseudocysts. Initial serology was positive for both T. cruzi and Leishmania, and immunohistochemistry supported a diagnosis of Leishmania. However, additional serology supported a T. cruzi infection, and cultivation of organisms isolated from a lymph node revealed morphology consistent with T. cruzi. In addition, PCR analysis resulted in a 504 bp fragment with 99% homology to a flagellar protein of T. cruzi. Although uncommon, autochthonous cases of both T. cruzi and Leishmania have been reported in the United States. Clinical signs observed with both diseases can show many similarities, cytology may be indistinguishable, as in this case, and serological cross-reactivity is common. This case demonstrates an unusual presentation of T. cruzi and the use of multiple testing strategies to support its diagnosis.

Analysis of the ITS region and partial ssu and lsu rRNA genes of Blastocystis and Proteromonas lacertae.

Blastocystis is a common single-celled enteric parasite found in a large variety of hosts. Recent molecular analysis supports the concept that this eukaryotic organism is a stramenopile most closely related to Proteromonas lacertae, a parasite of reptiles. In this study, the internal transcribed spacer region, partial small subunit rRNA and large subunit rRNA genes from 7 Blastocystis isolates (5 human, 1 pig and 1 sheep), and a Proteromonas lacertae isolate were amplified by PCR, cloned and sequenced. Blastocystis was found to be a typical eukaryote with both ITS1 and ITS2 regions present. Phylogenetic analysis based on the entire PCR amplicon revealed that the Blastocystis isolates did not segregate according to host or geographic origin. The highest sequence identities with the conserved Blastocystis 5.8S rDNA sequence were with the stramenopiles Fibrocapsa japonica, Chattonella marina, Cylindrotheca closterium and Hyphochytrium catenoides. The most parsimonious tree based on the 5.8S rDNA sequence from P. lacertae, 11 other stramenopiles, 2 fungi, 3 algae and 3 alveolates showed Blastocystis positioned within the stramenopiles, with P. lacertae as its closest relative. This work therefore supports the hypothesis that Blastocystis is most closely related to P. lacertae, and that it should be regarded as an unusual stramenopile.

Microsporidiosis in a Gouldian finch (Erythrura [Chloebia] gouldiae).

A 12-day-old nestling Gouldian finch (Erythrura [Chloebia] gouldiae) was presented for investigation of a mortality problem in nestling finches raised by Bengalese finch foster parents. On histological examination, large numbers of spores consistent with a microsporidian organism were present within the small intestinal mucosa. Electron microscopy and molecular studies (sequencing the 5' end of the ssu rRNA gene) further defined the organism as Encephalitozoon hellem. Sequence homology with other eukaryotes was determined using a BLASTN search from the NCBI GenBank database. The finch isolate sequences showed greater than 99% homology with those of previously reported human and avian isolates.

Characterization of a cytosolic aminopeptidase from Encephalitozoon intestinalis.

Aminopeptidase activity was detected in Encephalitozoon intestinalis using a fluorometric assay. The aminopeptidase was capable of hydrolysing different amino acids bound to 7-amino-4-trifluoromethyl coumarin, with maximal activity against the amino acid, leucine. Aminopeptidase activity was localized in E. intestinalis spores and in intracellular stages. Enzymatic activity was inhibited by the traditional aminopeptidase inhibitors, bestatin and its analogue, nitrobestatin. Inhibition with the chelating agents, EDTA and 1,10-phenanthroline, suggested that the enzyme activity belongs to the metalloaminopeptidase class. Subcellular fractionation demonstrated that maximal enzyme activity was localized in the cytosolic fraction. Direct fluorogenic substrate analysis by native polyacrylamide gel electrophoresis estimated a molecular weight of 70.8 kDa. Direct fluorogenic analysis by polyacrylamide ampholyte gel electrophoresis indicated an isoelectric point of 4.8. The enzyme was both heat (> 37 degrees C) and cold (< 0 degrees C) labile with an optimal activity at pH 7.2. This is the first report characterizing a cytosolic aminopeptidase in microsporidia.

Association of serologic status for Neospora caninum and postweaning feed efficiency in beef steers.

OBJECTIVE: To determine the effects of serologic status for Neospora caninum on short-term weight gain, feed intake, and feed efficiency (feed intake/gain). DESIGN: Longitudinal observational study. ANIMALS: 34 weaned mixed-breed beef steers. PROCEDURE: Serologic status for N. caninum was determined for each steer on days 0 (weaning), 88, 116, 144, 172, and 200, using an agglutination test. Individual steer body weight was measured on days 0, 88, 116, 144, 172, 200, and 242 (slaughter). Daily feed intake was monitored from days 116 through 242. Serologic status was matched to animal performance for the period immediately following serum sample collection. A mixed mode, using repeated-measures with an unstructured covariance matrix, was used in the analysis. Breed, age, and pen effects were controlled for in the analysis. RESULTS: A reduction in average daily gain for the period following a positive serologic result was detected for the entire trial (6 measurements/steer). This may have been attributed to a significant impairment in feed efficiency rather than to an impairment in feed intake. Changes in serologic status in individual steers over time were common; additionally, the effects of serologic status on steer performance were also transitory. CONCLUSIONS AND CLINICAL RELEVANCE: Significant reductions in short-term weight gain and feed efficiency were associated with the presence of antibodies against N. caninum in postweaning beef steers.

BIG: a calossin-like protein required for polar auxin transport in Arabidopsis.

Polar auxin transport is crucial for the regulation of auxin action and required for some light-regulated responses during plant development. We have found that two mutants of Arabidopsis-doc1, which displays altered expression of light-regulated genes, and tir3, known for its reduced auxin transport-have similar defects and define mutations in a single gene that we have renamed BIG. BIG is very similar to the Drosophila gene Calossin/Pushover, a member of a gene family also present in Caenorhabditis elegans and human genomes. The protein encoded by BIG is extraordinary in size, 560 kD, and contains several putative Zn-finger domains. Expression-profiling experiments indicate that altered expression of multiple light-regulated genes in doc1 mutants can be suppressed by elevated levels of auxin caused by overexpression of an auxin biosynthetic gene, suggesting that normal auxin distribution is required to maintain low-level expression of these genes in the dark. Double mutants of tir3 with the auxin mutants pin1, pid, and axr1 display severe defects in auxin-dependent growth of the inflorescence. Chemical inhibitors of auxin transport change the intracellular localization of the auxin efflux carrier PIN1 in doc1/tir3 mutants, supporting the idea that BIG is required for normal auxin efflux.