Leah Cohn

University of Missouri | Mizzou · Department of Veterinary Medicine and Surgery

Background: Serum 25-hydroxyvitamin (OH)D, C-reactive protein (CRP), and haptoglobin are useful biomarkers in various infectious diseases and inflammatory disorders in dogs, but their utility in histoplasmosis is unknown. Objective: Determine if serum 25(OH)D, CRP, and haptoglobin concentrations are different in dogs with histoplasmosis compared...

Pediatric dogs and cats within their first 12 weeks of life have important electrolyte requirements and physiologic considerations that may impact fluid therapy. Fluid requirements are higher in pediatrics, while fluid losses are greater due to underdeveloped physiologic responses. Hydration and volume status are difficult to assess in young animal...

Background: The magnitude of diagnostic abnormalities can influence the perception of clinical outcome. Extreme neutrophilic leukocytosis (ENL) is an uncommon finding caused by markedly increased granulopoiesis. A lack of recent, large-scale studies limits our understanding of the importance, causation, and prognosis associated with ENL in dogs....

Background Cytauxzoon felis is a life-threatening protozoan disease of cats. Identification of schizont-laden macrophages is a point-of-care diagnostic test for acute cytauxzoonosis. Hypothesis/Objectives The primary objective determined cytologic agreement between sample types to diagnose acute cytauxzoonosis. The secondary objective evaluated no...

Background In dogs, antimicrobial drugs are widely prescribed for aspiration pneumonia (AP) despite poor documentation of bacterial infection in AP (b-AP) using bronchoalveolar lavage fluid (BALF) analysis. Interpretating discordant cytology and culture results is challenging, contributing to lack of a criterion standard, and highlighting differenc...

Cytauxzoon felis is a tick-borne hemoprotozoon 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...

Case summary A castrated male domestic shorthair cat from a wooded area in Missouri had recovered from typical severe cytauxzoonosis at 4 years of age, after intensive in-hospital supportive care and administration of atovaquone and azithromycin. At 11 years of age, the same cat again experienced an acute febrile illness compatible with cytauxzoono...

Objectives The aim of this study was to evaluate the results of serum allergen-specific IgE testing in cats with a clinical diagnosis of asthma and to determine if the number of allergens with positive IgE reactivity and magnitude of positive IgE responses would be associated with the severity of clinical signs or airway eosinophilia. Methods Medi...

Background 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. Methods Recent...

Fever of unknown origin (FUO) is a persistent or recurrent fever for which the underlying source has not been identified despite diagnostic investigation. In people, 18F-fluoro-2-deoxyglucose positron emission tomography (18F-FDG-PET) alone or in combination with computed tomography (CT) is often beneficial in detecting the source of fever when oth...

Cytauxzoon felis is a tick-borne hemoparasite that causes cytauxzoonosis in domestic cats in the United States. Historically, feline cytauxzoonosis was reported to be nearly always fatal. However, increasing evidence of cats surviving acute infection and/or harboring a chronic, subclinical infection has suggested the existence of different C. felis...

The urinary bladder in healthy dogs has dogmatically been considered free of bacteria. This study used culture independent techniques to characterize the healthy canine urinary microbiota. Urine samples collected by antepubic cystocentesis from dogs without urinary infection were used for DNA extraction. Genital tract and rectal samples were collec...

Advances in the field of metagenomics using culture-independent methods of microbial identification have allowed characterization of rich and diverse communities of bacteria in the lungs of healthy humans, mice, dogs, sheep and pigs. These data challenge the long held belief that the lungs are sterile and microbial colonization is synonymous with p...

Young puppies and kittens have unique physiologic needs in regards to fluid therapy, which must address hydration, vascular fluid volume, electrolyte disturbances, or hypoglycemia. Pediatric patients have a higher fluid requirement compared with adults and can rapidly progress from mild dehydration to hypovolemia. Simultaneously, their small size m...

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 pr...

Phylogenetic analysis of cytb nucleotide sequence does not recover the five distinct lineages identified by analysis of concatenated mitochondrial and 18S sequences. Statistical support for clades are indicated at each node: posterior probabilities from Bayesian analysis (10 million generations of Markov chain Monte Carlo) are listed above nodes, w...

Primers utilized in additional B. vogeli PCR assays. (PDF)

Primers utilized in additional Babesia sp. Coco PCR assays. (PDF)

Phylogenetic analysis of cox1 nucleotide sequence does not recover the five distinct lineages identified by analysis of concatenated mitochondrial and 18S sequences. Statistical support for clades are indicated at each node: posterior probabilities from Bayesian analysis (10 million generations of Markov chain Monte Carlo) are listed above nodes, w...

Phylogenetic analysis of concatenated cox1 and cytb nucleotide sequence does not recover the five distinct lineages identified by analysis of concatenated mitochondrial and 18S sequences. Statistical support for clades are indicated at each node: posterior probabilities from Bayesian analysis (10 million generations of Markov chain Monte Carlo) are...

Primers utilized in additional C. felis PCR assays. (PDF)

Primers utilized in additional B. rossi PCR assays. (PDF)

Schematic of PCR amplification of B. vogeli and Babesia sp. Coco mitochondrial genomes. Because attempts at TIR amplifications were unsuccessful, primers were designed to amplify near full length mitochondrial genomes of species in five overlapping fragments. Primers for fragments 0–4 are indicated with arrows (forward primers: F0-F4, reverse prime...

Schematic of PCR amplification of B. microti-like sp. mitochondrial genome. Because of the mitochondrial genome structure of close relative B. microti is known to differ from that of Babesia sensu stricto species, an alternative approach was employed to amplify the B. microti-like sp. mitochondrial genome. Primers were designed to amplify near full...

Phylogenetic analysis of concatenated cox1 and cytb amino acid sequence recovers the five distinct lineages identified by analysis of concatenated mitochondrial and 18S sequences but with poorer statistical support than analysis cox1 amino acid alone. Statistical support for clades (bootstrap values from Maximum Likelihood analysis, 100 bootstrap r...

Primers utilized in additional B. conradae PCR assays. (PDF)

Locations of protein-coding genes and rRNA fragments within Piroplasmida mitochondrial genomes. Gene/fragment coordinates with a white background are coded on the sense strand, while those highlighted in yellow are on the antisense strand. Some genes/fragments were not identified in some mitochondrial genomes (indicated in green and with “No ID”) w...

Schematic of PCR amplification of B. canis, B. rossi, and C. felis mitochondrial genomes. Primers were designed to amplify near full length mitochondrial genomes in three overlapping fragments. Primers for fragments 1–3 and TIRs are indicated with arrows (forward primers: F1-F3, reverse primers: R1-R3, TIR primers: TIR F/R). Genes shown above the c...

Schematic of PCR amplification of B. conradae mitochondrial genome. Because initial attempts at amplifying near full length mitochondrial genome was unsuccessful, primers were designed to amplify near full length B. conradae mitochondrial genome in six overlapping fragments. Primers for fragments 0–4 are indicated with arrows (forward primers: F0-F...

Phylogenetic analysis of cytb amino acid sequence does not recover the five distinct lineages identified by analysis of concatenated mitochondrial and 18S sequences. Statistical support for clades (bootstrap values from Maximum Likelihood analysis, 100 bootstrap replicates) are indicated below each node. Tree is drawn to scale, with branch lengths...

Primers utilized in additional B. canis PCR assays. (PDF)

Primers utilized in additional B. microti-like sp. PCR assays. (PDF)

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 w...

Practical relevance Cytauxzoonosis is a life-threatening hematoprotozoal disease with a rapidly progressive clinical course. Once considered a rare disease only relevant to a small geographic area, it is now recognized in more than about a third of the United States. The geographic range seems likely to increase with expansion of the range of the v...

Airway remodeling is a prominent feature of feline allergic asthma but requires biopsy for characterization. Computed tomography (CT) has appeal as a minimally invasive diagnostic test. The purpose of this prospective case-control study was to compare indices of airway remodeling between cats with experimentally induced, spontaneous asthma and heal...

To characterize hemostasis and determine if disseminated intravascular coagulation (DIC) is present in cats with cytauxzoonosis. Cross-sectional study. University teaching hospital. Five client-owned cats with cytologic and PCR-confirmed cytauxzoonosis. None. Admission samples were collected for hemostasis testing including platelet count, activate...

Cytauxzoon felis is a virulent tick-transmitted protozoan parasite that infects felines. Cytauxzoonosis was previously believed to be uniformly fatal in domestic cats. Treatment combining atovaquone and azithromycin (A&A) has been associated with survival rates over 60%. Atovaquone, a ubiquinone analogue, targets C. felis cytochrome b (cytb), of wh...

Recently, the increased cost and decreased availability of doxycycline has sparked an interest in using minocycline as an alternative. The purpose of this study was to determine the pharmacokinetics of minocycline in domestic cats in order to facilitate dosage decisions. Purpose-bred, young adult cats were administered a single dose of either intra...

Background Infection with Cytauxzoon felis in domestic cats can cause fever, lethargy, depression, inappetence, icterus, and often death. With a high mortality rate, cytauxzoonosis was historically considered a fatal disease. Within the last 15 years, cats with or without treatment have been recognized as chronically infected survivors of C. felis...

Background Mesenchymal stem cells (MSCs) decrease airway eosinophilia, airway hyperresponsiveness (AHR), and remodeling in murine models of acutely induced asthma. We hypothesized that MSCs would diminish these hallmark features in a chronic feline asthma model.Objective To document effects of allogeneic, adipose-derived MSCs on airway inflammation...

Nasal disease often manifests as nasal discharge with or without other nasal signs. Attention to signalment, history, and physical examination findings often facilitates a differential diagnosis. Imaging techniques and tissue sampling for microscopic examination are usually necessary for diagnosis. Advanced imaging offers important advantages over...

Objective: To investigate long-term outcomes and owner-perceived quality of life associated with sudden acquired retinal degeneration syndrome (SARDS) in dogs. Design: Survey study. Animals: 100 dogs with SARDS examined at 5 academic veterinary institutions from 2005 to 2010. Procedures: The diagnosis was based on documented acute vision los...

Cytauxzoonosis is an emerging infectious disease of domestic cats (Felis catus) caused by the apicomplexan protozoan parasite Cytauxzoon felis. The growing epidemic, with its high morbidity and mortality points to the need for a protective vaccine against cytauxzoonosis. Unfortunately, the causative agent has yet to be cultured continuously in vitr...

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-protozoa...

Four way Venn Diagram: Protein coding genes of Cytauxzoon felis and related apicomplexan parasites. (TIF)

Nucleotide sequence alignment of syntenic genes C. felis cf76-1 (isolate from the C. felis genome sequence), cf76-2 (the most common sequence among eleven geographically diverse C. felis isolates), T. parva p67 (GenBank U40703.1), T. annulata SPAG-1 (GenBank M63017.1), and B. bovis BOV57 (GenBank FJ805276.1). (DOC)

Amino acid sequence alignment of syntenic genes C. felis cf76-1 (isolate from the C. felis genome sequence), cf76-2 (the most common sequence among eleven geographically diverse C. felis isolates), T. parva p67 (GenBank AAB06703.1), T. annulata SPAG-1 (GenBank AAA30134.1), and B. bovis BOV57 (GenBank ACY08791.1) (shading: black- identical amino aci...

Phylogenetic reconstruction of cf76 across 11 isolates. Posterior probability of clades is indicated on branches. Sample names are based on the name of the individual animal and the state from which the sample was taken (AR - Arkansas, KS - Kansas, MO - Missouri, NC - North Carolina, OK - Oklahoma, OH - Ohio, TN - Tennessee, VA - Virginia). Scale b...

Amino acid sequences of syntenic gene C. felis cf76 from geographic isolates across the southeastern and southwestern United States (shading: black- identical amino acids, grey- similar amino acids). (DOC)

Airway hyperresponsiveness (AHR) is a key feature of asthma and can be measured using bronchoprovocation. Direct (methacholine, MCh) or indirect (adenosine-5-monophosphate, AMP; or mannitol) bronchoprovocants are used in human patients, the latter inducing AHR only with pre-existing airway inflammation. The present study compared the responses to d...

Cytauxzoon felis, an emerging virulent protozoan parasite that infects domestic cats, is treated with atovaquone and azithromycin (A&A). Atovaquone targets parasite cytochrome b. We characterized the C. felis cytochrome b gene (cytb) in cats with cytauxzoonosis and found a cytb genotype that was associated with survival in A&A-treated cats.

Allergen-specific rush immunotherapy (RIT) shows promise in treating asthma; however, pet cats will likely require at least initial concurrent glucocorticoids (GCs) to control serious clinical signs. How the immunosuppressive effects of GCs would impact RIT in cats is unknown. The hypothesis of this study was that oral, but not inhaled GCs will dim...

Nebulized lidocaine may be a corticosteroid-sparing drug in human asthmatics, reducing airway resistance and peripheral blood eosinophilia. We hypothesized that inhaled lidocaine would be safe in healthy and experimentally asthmatic cats, diminishing airflow limitation and eosinophilic airway inflammation in the latter population. Healthy (n = 5) a...

Background Cytauxzoon felis is a hemoprotozoal parasite that causes substantial morbidity and mortality during the acute phase of infection in cats. However, cats that survive the acute illness remain persistently infected and may serve as a reservoir for the tick-transmitted pathogen. Objective We investigated the ability of the antiprotozoal comp...

The ecological distribution of Cytauxzoon felis, an often-fatal tick-borne apicomplexan that infects domestic cats, has not been evaluated or identified despite its continued emergence. Infection of C. felis is characterized by lethargy, icterus, fever, anorexia, anemia, and death. The natural vertebrate reservoir of C. felis is the bobcat (Lynx ru...

Objective: To determine whether apparently healthy captive-born wild felids that were not native to North America and were housed in an area endemic for Cytauxzoon felis harbored the pathogen. Design: Prospective observational case series. Animals: 11 captive-born wild felids that were (1 bobcat [Lynx rufus] and 1 cougar [Puma concolor]) or we...

Blockade of tyrosine kinase signaling by masitinib, a c-kit/PDGF receptor tyrosine kinase inhibitor, can modulate allergic airway inflammation, but effects on lung mechanics have not been well characterized. We hypothesized masitinib would decrease airway eosinophilia and consequently improve pulmonary mechanics in a feline allergic asthma model. A...

Cytauxzoon felis is a hemoprotozoan parasite of cats capable of causing severe, often fatal disease during acute infection, but cats that survive the acute stage of disease become chronic carriers. These otherwise healthy carriers are capable of transmitting the infection to other cats via the bite of a vector tick. A variety of other hematoprotozo...

This study evaluated the exposure of dogs to three different Ehrlichia spp. in the south and central regions of the United States where vector-borne disease prevalence has been previously difficult to ascertain, particularly beyond the metropolitan areas. Dog blood samples (n = 8,662) were submitted from 14 veterinary colleges, 6 private veterinary...

Acute respiratory distress syndrome (ARDS) was diagnosed in 2 dogs with acute dyspnea. Short-term positive pressure ventilation and intense critical and nursing care were provided. Both dogs improved and were discharged. Few reports describe successful recovery from ARDS. Due to advances in positive pressure ventilation and improvement in the suppo...

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 do...

Glucocorticoids (GCs) are palliative for allergic asthma, but allergen-specific immunotherapy (ASIT), which relies on identification of allergens, represents a potentially curative treatment. The purpose of this study was to determine if oral or inhaled GCs would interfere with identification of sensitizing allergens. The hypothesis was that oral b...

Feline respiratory disease complex (FRDC) refers to the characteristic acute presentation of a contagious respiratory or ocular disease caused by one or multiple pathogens. Environmental and host factors impact the transmission, clinical presentation, preventive strategy, and treatment of affected cats. The FRDC is especially problematic in setting...

The study hypothesis was that in experimentally asthmatic cats rush immunotherapy (RIT) using allergens not completely matched with sensitizing allergen(s) would at least partially attenuate the asthmatic phenotype and modulate the aberrant immune response. In phase I, cats sensitized to Bermuda grass allergen (BGA), house dust mite allergen (HDMA)...

A 2-year-old, female spayed, domestic shorthair cat presented to the University of Missouri-Veterinary Medical Teaching Hospital (UMC-VMTH) with an approximately 11-month history of fluid-draining pockets along her ventral thorax and axillae. The skin in these regions was erythematous, and multiple areas drained a serous to serosanguinous fluid. Fl...

N-acetylcysteine (NAC), a mucolytic and antioxidant, is speculated to cause bronchoconstriction in cats when delivered via aerosol. We hypothesized that in cats with experimental asthma, aerosol delivery of NAC (400mg cumulative dose) via an endotracheal tube would increase airflow limitation as measured by ventilator-acquired mechanics. After endo...

To determine the lowest dose of cosyntropin on a per body weight basis that would produce maximal cortisol and aldosterone secretion and the ideal timing of blood sample collection after ACTH stimulation in healthy cats. Randomized crossover trial. 7 adult sexually intact male purpose-bred cats. Each cat received saline (0.9% NaCl) solution (contro...