Journal of Veterinary Diagnostic Investigation, May 19, 2023
Rapid growth in aquaculture has resulted in high-density production systems in ecologically and g... more Rapid growth in aquaculture has resulted in high-density production systems in ecologically and geographically novel conditions in which the emergence of diseases is inevitable. Well-characterized methods for detection and surveillance of infectious diseases are vital for rapid identification, response, and recovery to protect economic and food security. We implemented a proof-of-concept approach for virus detection using a known high-consequence fish pathogen, infectious salmon anemia virus (ISAV), as the archetypal pathogen. In fish infected with ISAV, we integrated histopathology, virus isolation, whole-genome sequencing (WGS), electron microscopy (EM), in situ hybridization (ISH), and reverse transcription real-time PCR (RT-rtPCR). Fresh-frozen and formalin-fixed tissues were collected from virus-infected, control, and sham-infected Atlantic salmon ( Salmo salar). Microscopic differences were not evident between uninfected and infected fish. Viral cytopathic effect was observed in cell cultures inoculated with fresh-frozen tissue homogenates from 3 of 3 ISAV-infected and 0 of 4 uninfected or sham-infected fish. The ISAV genome was detected by shotgun metagenomics in RNA extracted from the medium from 3 of 3 inoculated cell cultures, 3 of 3 infected fish, and 0 of 4 uninfected or sham-infected fish, yielding sufficient coverage for de novo assembly. An ISH probe against ISAV revealed ISAV genome in multiple organs, with abundance in renal hematopoietic tissue. Virus was detected by RT-rtPCR in gill, heart, kidney, liver, and spleen. EM and metagenomic WGS from tissues were challenging and unsuccessful. Our proof-of-concept methodology has promise for detection and characterization of unknown aquatic pathogens and also highlights some associated methodology challenges that require additional investigation.
A 6-year-old, spayed female Labrador/Weimaraner cross-breed dog that had previously lived in Ariz... more A 6-year-old, spayed female Labrador/Weimaraner cross-breed dog that had previously lived in Arizona presented in Montana for an annual examination with an incidentally enlarged popliteal lymph node, which was subsequently biopsied. Histologically, the lymph node was expanded by eosinophil-rich granulomas with both extracellular and intrahistiocytic green algae. These algae had intracytoplasmic, birefringent and refractile granules, readily formed 2-3 mm green colonies on Columbia blood agar medium, and ultrastructurally had a multilayered cell wall and intracytoplasmic chloroplasts. Amplified product from the internal transcribed spacer (ITS) and D1/D2 regions of the 28S ribosomal RNA gene had high sequence identity to Scenedesmus sp. Despite similar infection in the retropharyngeal lymph node one year later, the animal remained otherwise healthy with no clinical signs. To the authors’ knowledge, this is the first case of Scenedesmus species infection in a dog and is a differential diagnosis for Coccidioides immitis.
C oronaviruses infect multiple mammal species, and SARS-CoV-2, the etiologic agent of COVID-19, l... more C oronaviruses infect multiple mammal species, and SARS-CoV-2, the etiologic agent of COVID-19, likely jumped to humans from a mammal source (1). Although the virus is currently spreading person-toperson, the angiotensin converting enzyme-2 receptor involved in SARS-CoV-2 transmission is present in multiple species, and there are numerous reports of infections in pets (24). As of October 17, 2022, a total of 110 domestic cats and 95 domestic dogs in the United States had been reported by the US Department of Agriculture Animal and Plant Health Inspection Service to have SARS-CoV-2 infection (5).
Rickettsiella infection was diagnosed in 4 adult emperor scorpions (Pandinus imperator) from 2 di... more Rickettsiella infection was diagnosed in 4 adult emperor scorpions (Pandinus imperator) from 2 different collections over a 3-year period. One case had a 2-day history of weakness, failure to lift the tail, or respond to stimulation, with rapid progression to death. The other 3 cases were found dead. There were no gross lesions, but histologically the hemolymphatic vasculature and sinuses, presumed hematopoietic organ, heart, midgut and midgut diverticula, nerves, and skeletal muscle were infiltrated with phagocytic and granular hemocytes with necrosis. Phagocytic hemocytes contained abundant intracellular microorganisms that were Fite's acid-fast-positive, Macchiavello-positive, variably gram-positive or gram-negative, and Grocott's methenamine silver-negative. By transmission electron microscopy, hemocytes contained numerous phagocytic vacuoles with small dense bacterial forms (mean 0.603 Â 0.163 mm) interspersed with large bacterial forms (mean 1.265 Â 0.505 mm) and few intermediary forms with electrondense nucleoids and membrane-bound crystalline arrays (average 4.72 mm). Transmission electron microscopy findings were consistent with bacteria of the family Coxiellaceae. Based on sequencing the 16S ribosomal RNA gene, the identity was confirmed as Rickettsiella, and phylogenetic analysis of protein-coding genes gidA, rspA, and sucB genes suggested the emperor scorpion pathogen as a new species. This study identifies a novel Rickettsiella causing infection in emperor scorpions and characterizes the unique pathological findings of this disease. We suggest this organism be provisionally named Rickettsiella scorpionisepticum.
A novel foot disease in free-ranging elk (Cervus elaphus) in southwestern Washington State emerge... more A novel foot disease in free-ranging elk (Cervus elaphus) in southwestern Washington State emerged in 2008 and spread throughout the region. Initial studies showed adult elk had chronic hoof overgrowth, sole ulcers, and sloughed hoof capsules, but no cause was determined. To identify possible causes and characterize the earliest lesions, 9-, 7-, and 3-month-old elk were collected. Nine-month-old elk had sole ulcers (3/9 elk) and sloughed/overgrown hoof capsules (4/9 elk) similar to adults. Histologically, lesions consisted of coronary, heel bulb, and interdigital ulcers with suppurative inflammation, epithelial hyperplasia, deeply invasive spirochetes, and underrunning of the hoof capsule and heel-sole junction. Spirochetes were identified as Treponema via immunohistochemistry and polymerase chain reaction (PCR). Seven-month-old elk had similar underrunning foot ulcers (6/8 elk) with Treponema identified in all lesions but no chronic overgrowth or sloughed hoof capsules. Three-month-old calves had superficial coronary erosions with no inflammation or identifiable spirochetes (3/5 elk) but were culture/PCR positive for Treponema, suggesting possible early lesions. Lesions from 9-and 7-month-old elk included aerobic and anaerobic bacteria, many of which are associated with infectious foot disease in livestock. Antibody enzyme-linked immunosorbent assay of 7-and 3-month-old elk from the enzootic region showed a trend toward increased Treponema antibody titers compared to normal control elk from outside the region, further supporting the significance of Treponema in the pathogenesis of foot disease. Treponeme-associated hoof disease (TAHD) in elk, a debilitating and progressive condition, shares similarities to bovine digital dermatitis and contagious ovine digital dermatitis.
Escherichia albertii has been associated with diarrhea in humans but not with disease or infectio... more Escherichia albertii has been associated with diarrhea in humans but not with disease or infection in animals. However, in December 2004, E. albertii was found, by biochemical and genetic methods, to be the probable cause of death for redpoll fi nches (Carduelis fl ammea) in Alaska. Subsequent investigation found this organism in dead and subclinically infected birds of other species from North America and Australia. Isolates from dead fi nches in Scotland, previously identifi ed as Escherichia coli O86:K61, also were shown to be E. albertii. Similar to the isolates from humans, E. albertii isolates from birds possessed intimin (eae) and cytolethal distending toxin (cdtB) genes but lacked Shiga toxin (stx) genes. Genetic analysis of eae and cdtB sequences, multilocus sequence typing, and pulsed-fi eld gel electrophoresis patterns showed that the E. albertii strains from birds are heterogeneous but similar to isolates that cause disease in humans.
The genus Neorickettsia includes obligate, intracellular bacteria responsible for diseases includ... more The genus Neorickettsia includes obligate, intracellular bacteria responsible for diseases including Potomac horse fever caused by Neorickettsia risticii and salmon poisoning disease (SPD) caused by Neorickettsia helminthoeca. The Stellanchasmus falcatus (SF) agent is a member of this genus previously associated only with mild clinical signs in dogs. Between 2013 and 2016, 3 dogs in Washington State (USA) presented with disease suggestive of SPD, but N. helminthoeca was not detected by molecular techniques. Clinical signs included depression, anorexia, and diarrhea. Cytologic examination of aspirates supported a diagnosis of granulomatous lymphadenitis with organisms suggestive of Neorickettsia. Dogs either died or were humanely euthanized due to poor response to therapy. Necropsy findings included lymphadenomegaly and hepatomegaly. Histopathology identified granulomatous and lymphoplasmacytic splenitis, lymphadenitis, enteritis, and hepatitis with extensive necrosis. Neorickettsia DNA was detected using genus-specific primers and direct sequencing showed 100% sequence identity to the SF agent in all 3 dogs. This is the first clinicopathologic description of severe disease in dogs attributed to the SF agent. These findings may suggest the emergence of a novel neorickettsial disease in the Pacific Northwest.
A 25-yr-old Diana monkey ( Cercopithecus diana ) with a 1.5-yr history of chronic colitis and dia... more A 25-yr-old Diana monkey ( Cercopithecus diana ) with a 1.5-yr history of chronic colitis and diarrhea was found to have disseminated granulomatous disease with intralesional acid fast bacilli. Bacilli were identified as Mycobacterium genavense by polymerase chain reaction, sequencing of the 16S-23S ribosomal RNA intergenic spacer (ITS) gene, and mycolic acid analysis by high-performance liquid chromatography. Mycobacterium genavense is a common cause of mycobacteriosis in free-ranging and captive birds. In addition, recognition of opportunistic infection in human immunodeficiency virus-positive patients is increasing. Disease manifestations of M. genavense are similar to Mycobacterium avium complex (MAC) and include fever, wasting, and diarrhea with disseminated disease. Similar clinical signs and lesions were observed in this monkey. Mycobacterium genavense should be considered as a differential for disseminated mycobacterial disease in nonhuman primates as this agent can mimic MAC and related mycobacteria.
T he bacterium Mycoplasma bovis is an economically important pathogen of cattle that contributes ... more T he bacterium Mycoplasma bovis is an economically important pathogen of cattle that contributes to the multifactorial bovine respiratory disease complex. In addition to causing respiratory disease, this bacterium can cause polyarthritis, mastitis, otitis media, and a chronic pneumonia-polyarthritis syndrome, impacting beef and dairy cattle worldwide (1). Despite increased recognition of its role in economic loss in the cattle industry, M. bovis remains a clinical challenge because of a common carrier state in clinically healthy animals, variable disease expression, intermittent shedding, and the lack of rapid accurate diagnostic assays (1,2). Clinical disease is not considered necessary to maintain M. bovis in populations, and M. bovis is commonly detected in asymptomatic adult feedlot cattle (2). Although the upper respiratory tract mucosa is a primary site for M. bovis colonization, presence of the bacterium in the lung is variable in occurrence and clinical manifestation. In 1 study, M. bovis was detected in 46% of cattle with normal lungs, 82% of cattle with acute fibrinous pneumonia, and 98% of cattle with chronic pneumonia (3). Manifestation of M. bovis-associated respiratory disease is particularly common in the wake of stress (e.g., from transportation, comingling, feedlot entry, and harsh temperatures or conditions). In the early 2000s, M. bovis caused several highmortality (case-fatality rate 45%) epizootics in bison (Bison bison) in North America (4). These events raised concern about emergent virulent strains, and research began to characterize isolates from different host species (5). An important difference between outbreaks of mycoplasmosis in bison and cattle is that, in the former, few or no co-infecting bacterial or viral pathogens are consistently detected (4,6-8). Although M. bovis virulence factors are poorly defined, evasion of immune response is implicated in maintaining chronic infection (9). One study found that that up to 79% of bison herds in western Canada have >1 M. bovis-seropositive animal and that 8 of 11 herds with no history of M. bovis disease had seropositive animals (10). These findings suggest that host response to M. bovis varies; some exposed bison become subclinical carriers and might also
Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc, 2017
A 10-y-old Watusi ( Bos taurus africanus) steer housed at a drive-through game park in Winston, O... more A 10-y-old Watusi ( Bos taurus africanus) steer housed at a drive-through game park in Winston, Oregon developed severe clinical illness including fever, marked nasal discharge, injected scleral and conjunctival membranes, plus oral hemorrhages and erosions. The animal responded poorly to supportive treatment and was euthanized. Additional gross findings at postmortem examination included papules and erosive lesions on the tongue, hemorrhagic large intestine, and multifocal cardiac hemorrhages. Histopathologic findings included multifocal lymphoplasmacytic vasculitis plus fibrin exudation in heart and tongue. Total DNA obtained from the splenic samples was positive for alcelaphine gammaherpesvirus 1 (AlHV-1) as tested by a multiplex PCR for malignant catarrhal fever (MCF) viruses. The AlHV-1 detection was further confirmed by amplification and sequencing of a viral DNA polymerase gene fragment, which was identical to AlHV-1 sequences in GenBank. This was the first diagnosis of clini...
Highly pathogenic avian influenza (HPAI) is a major viral disease of poultry characterized by acu... more Highly pathogenic avian influenza (HPAI) is a major viral disease of poultry characterized by acute onset, systemic infection, and rapid death. In January 2015, H5N2 HPAI was identified by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and gene sequencing as the cause of rapid death in 40 of 390 ring-necked pheasants (approximately 10% mortality), raised in a game bird farm in Washington State. We report clinicopathologic findings and viral antigen distribution in pheasants that died during the outbreak. Affected birds were depressed with reluctance to move, ruffled feathers, and drooping heads. Congestion of the cerebellar meningeal blood vessels was the only consistent gross pathologic finding. Meningoencephalitis with vasculitis and necrosis in the spleen and heart were the major microscopic lesions in the birds. Viral antigen was consistently detected in the brain, heart, and ovary with variable presence in other organs.
Twenty-two feral rock pigeons (<i>Columba livia</i>) from 10 counties in California w... more Twenty-two feral rock pigeons (<i>Columba livia</i>) from 10 counties in California with ataxia, torticollis, and difficulty standing and flying were admitted to rehabilitation centers in late winter and spring of 2017 and died or were euthanized. Common necropsy findings included thin body condition, generalized deep red discoloration of organs, and hemorrhagic subcutaneous neck tissues. Meningoencephalitis was observed microscopically in 16 pigeons, and 3 also had protozoal schizonts in the brain. The most consistently affected regions of the brain were cerebellum and brainstem. Skeletal muscles, and less frequently the heart, contained large intrasarcoplasmic bradyzoites typically without inflammation. Fifteen of the 22 birds tested positive using pan-<i>Sarcocystis</i> polymerase chain reaction. The sequence of the amplicon was most closely related to <i>S. calchasi</i>, and the 8 subtyped sequences had 100% homology with <i>S. calchasi&...
Journal of zoo and wildlife medicine : official publication of the American Association of Zoo Veterinarians, 2015
A 17-yr-old female fallow deer presented with ataxia, inappetence, decreased fecal output, and de... more A 17-yr-old female fallow deer presented with ataxia, inappetence, decreased fecal output, and decreased mentation. A complete blood count demonstrated leukocytosis (24.1×10(3)/μl, n=1.16-7.38×10(3)/μl), characterized by lymphocytosis (22.89×10(3)/μl, n=0.18-3.65×10(3)/μl), anemia (packed cell volume 20%, n=29.0-55.8%), decreased red blood cell count (4.1×10(3)/μl, n=6.86-14.72×10(3)/μl), and decreased hemoglobin (7.5 g/dl, n=9.4-19.2 g/dl). Numerous mature, well-differentiated lymphocytes were noted on the blood film. Despite treatment and clinical improvement, the decision was made to euthanize the deer. Histopathology identified a monomorphic population of CD3 positive, CD79a negative small lymphocytes replacing most of the hematopoietic tissue in the bone marrow without evidence of tissue invasion. Results of viral screening were negative.
Journal of Veterinary Diagnostic Investigation, May 19, 2023
Rapid growth in aquaculture has resulted in high-density production systems in ecologically and g... more Rapid growth in aquaculture has resulted in high-density production systems in ecologically and geographically novel conditions in which the emergence of diseases is inevitable. Well-characterized methods for detection and surveillance of infectious diseases are vital for rapid identification, response, and recovery to protect economic and food security. We implemented a proof-of-concept approach for virus detection using a known high-consequence fish pathogen, infectious salmon anemia virus (ISAV), as the archetypal pathogen. In fish infected with ISAV, we integrated histopathology, virus isolation, whole-genome sequencing (WGS), electron microscopy (EM), in situ hybridization (ISH), and reverse transcription real-time PCR (RT-rtPCR). Fresh-frozen and formalin-fixed tissues were collected from virus-infected, control, and sham-infected Atlantic salmon ( Salmo salar). Microscopic differences were not evident between uninfected and infected fish. Viral cytopathic effect was observed in cell cultures inoculated with fresh-frozen tissue homogenates from 3 of 3 ISAV-infected and 0 of 4 uninfected or sham-infected fish. The ISAV genome was detected by shotgun metagenomics in RNA extracted from the medium from 3 of 3 inoculated cell cultures, 3 of 3 infected fish, and 0 of 4 uninfected or sham-infected fish, yielding sufficient coverage for de novo assembly. An ISH probe against ISAV revealed ISAV genome in multiple organs, with abundance in renal hematopoietic tissue. Virus was detected by RT-rtPCR in gill, heart, kidney, liver, and spleen. EM and metagenomic WGS from tissues were challenging and unsuccessful. Our proof-of-concept methodology has promise for detection and characterization of unknown aquatic pathogens and also highlights some associated methodology challenges that require additional investigation.
A 6-year-old, spayed female Labrador/Weimaraner cross-breed dog that had previously lived in Ariz... more A 6-year-old, spayed female Labrador/Weimaraner cross-breed dog that had previously lived in Arizona presented in Montana for an annual examination with an incidentally enlarged popliteal lymph node, which was subsequently biopsied. Histologically, the lymph node was expanded by eosinophil-rich granulomas with both extracellular and intrahistiocytic green algae. These algae had intracytoplasmic, birefringent and refractile granules, readily formed 2-3 mm green colonies on Columbia blood agar medium, and ultrastructurally had a multilayered cell wall and intracytoplasmic chloroplasts. Amplified product from the internal transcribed spacer (ITS) and D1/D2 regions of the 28S ribosomal RNA gene had high sequence identity to Scenedesmus sp. Despite similar infection in the retropharyngeal lymph node one year later, the animal remained otherwise healthy with no clinical signs. To the authors’ knowledge, this is the first case of Scenedesmus species infection in a dog and is a differential diagnosis for Coccidioides immitis.
C oronaviruses infect multiple mammal species, and SARS-CoV-2, the etiologic agent of COVID-19, l... more C oronaviruses infect multiple mammal species, and SARS-CoV-2, the etiologic agent of COVID-19, likely jumped to humans from a mammal source (1). Although the virus is currently spreading person-toperson, the angiotensin converting enzyme-2 receptor involved in SARS-CoV-2 transmission is present in multiple species, and there are numerous reports of infections in pets (24). As of October 17, 2022, a total of 110 domestic cats and 95 domestic dogs in the United States had been reported by the US Department of Agriculture Animal and Plant Health Inspection Service to have SARS-CoV-2 infection (5).
Rickettsiella infection was diagnosed in 4 adult emperor scorpions (Pandinus imperator) from 2 di... more Rickettsiella infection was diagnosed in 4 adult emperor scorpions (Pandinus imperator) from 2 different collections over a 3-year period. One case had a 2-day history of weakness, failure to lift the tail, or respond to stimulation, with rapid progression to death. The other 3 cases were found dead. There were no gross lesions, but histologically the hemolymphatic vasculature and sinuses, presumed hematopoietic organ, heart, midgut and midgut diverticula, nerves, and skeletal muscle were infiltrated with phagocytic and granular hemocytes with necrosis. Phagocytic hemocytes contained abundant intracellular microorganisms that were Fite's acid-fast-positive, Macchiavello-positive, variably gram-positive or gram-negative, and Grocott's methenamine silver-negative. By transmission electron microscopy, hemocytes contained numerous phagocytic vacuoles with small dense bacterial forms (mean 0.603 Â 0.163 mm) interspersed with large bacterial forms (mean 1.265 Â 0.505 mm) and few intermediary forms with electrondense nucleoids and membrane-bound crystalline arrays (average 4.72 mm). Transmission electron microscopy findings were consistent with bacteria of the family Coxiellaceae. Based on sequencing the 16S ribosomal RNA gene, the identity was confirmed as Rickettsiella, and phylogenetic analysis of protein-coding genes gidA, rspA, and sucB genes suggested the emperor scorpion pathogen as a new species. This study identifies a novel Rickettsiella causing infection in emperor scorpions and characterizes the unique pathological findings of this disease. We suggest this organism be provisionally named Rickettsiella scorpionisepticum.
A novel foot disease in free-ranging elk (Cervus elaphus) in southwestern Washington State emerge... more A novel foot disease in free-ranging elk (Cervus elaphus) in southwestern Washington State emerged in 2008 and spread throughout the region. Initial studies showed adult elk had chronic hoof overgrowth, sole ulcers, and sloughed hoof capsules, but no cause was determined. To identify possible causes and characterize the earliest lesions, 9-, 7-, and 3-month-old elk were collected. Nine-month-old elk had sole ulcers (3/9 elk) and sloughed/overgrown hoof capsules (4/9 elk) similar to adults. Histologically, lesions consisted of coronary, heel bulb, and interdigital ulcers with suppurative inflammation, epithelial hyperplasia, deeply invasive spirochetes, and underrunning of the hoof capsule and heel-sole junction. Spirochetes were identified as Treponema via immunohistochemistry and polymerase chain reaction (PCR). Seven-month-old elk had similar underrunning foot ulcers (6/8 elk) with Treponema identified in all lesions but no chronic overgrowth or sloughed hoof capsules. Three-month-old calves had superficial coronary erosions with no inflammation or identifiable spirochetes (3/5 elk) but were culture/PCR positive for Treponema, suggesting possible early lesions. Lesions from 9-and 7-month-old elk included aerobic and anaerobic bacteria, many of which are associated with infectious foot disease in livestock. Antibody enzyme-linked immunosorbent assay of 7-and 3-month-old elk from the enzootic region showed a trend toward increased Treponema antibody titers compared to normal control elk from outside the region, further supporting the significance of Treponema in the pathogenesis of foot disease. Treponeme-associated hoof disease (TAHD) in elk, a debilitating and progressive condition, shares similarities to bovine digital dermatitis and contagious ovine digital dermatitis.
Escherichia albertii has been associated with diarrhea in humans but not with disease or infectio... more Escherichia albertii has been associated with diarrhea in humans but not with disease or infection in animals. However, in December 2004, E. albertii was found, by biochemical and genetic methods, to be the probable cause of death for redpoll fi nches (Carduelis fl ammea) in Alaska. Subsequent investigation found this organism in dead and subclinically infected birds of other species from North America and Australia. Isolates from dead fi nches in Scotland, previously identifi ed as Escherichia coli O86:K61, also were shown to be E. albertii. Similar to the isolates from humans, E. albertii isolates from birds possessed intimin (eae) and cytolethal distending toxin (cdtB) genes but lacked Shiga toxin (stx) genes. Genetic analysis of eae and cdtB sequences, multilocus sequence typing, and pulsed-fi eld gel electrophoresis patterns showed that the E. albertii strains from birds are heterogeneous but similar to isolates that cause disease in humans.
The genus Neorickettsia includes obligate, intracellular bacteria responsible for diseases includ... more The genus Neorickettsia includes obligate, intracellular bacteria responsible for diseases including Potomac horse fever caused by Neorickettsia risticii and salmon poisoning disease (SPD) caused by Neorickettsia helminthoeca. The Stellanchasmus falcatus (SF) agent is a member of this genus previously associated only with mild clinical signs in dogs. Between 2013 and 2016, 3 dogs in Washington State (USA) presented with disease suggestive of SPD, but N. helminthoeca was not detected by molecular techniques. Clinical signs included depression, anorexia, and diarrhea. Cytologic examination of aspirates supported a diagnosis of granulomatous lymphadenitis with organisms suggestive of Neorickettsia. Dogs either died or were humanely euthanized due to poor response to therapy. Necropsy findings included lymphadenomegaly and hepatomegaly. Histopathology identified granulomatous and lymphoplasmacytic splenitis, lymphadenitis, enteritis, and hepatitis with extensive necrosis. Neorickettsia DNA was detected using genus-specific primers and direct sequencing showed 100% sequence identity to the SF agent in all 3 dogs. This is the first clinicopathologic description of severe disease in dogs attributed to the SF agent. These findings may suggest the emergence of a novel neorickettsial disease in the Pacific Northwest.
A 25-yr-old Diana monkey ( Cercopithecus diana ) with a 1.5-yr history of chronic colitis and dia... more A 25-yr-old Diana monkey ( Cercopithecus diana ) with a 1.5-yr history of chronic colitis and diarrhea was found to have disseminated granulomatous disease with intralesional acid fast bacilli. Bacilli were identified as Mycobacterium genavense by polymerase chain reaction, sequencing of the 16S-23S ribosomal RNA intergenic spacer (ITS) gene, and mycolic acid analysis by high-performance liquid chromatography. Mycobacterium genavense is a common cause of mycobacteriosis in free-ranging and captive birds. In addition, recognition of opportunistic infection in human immunodeficiency virus-positive patients is increasing. Disease manifestations of M. genavense are similar to Mycobacterium avium complex (MAC) and include fever, wasting, and diarrhea with disseminated disease. Similar clinical signs and lesions were observed in this monkey. Mycobacterium genavense should be considered as a differential for disseminated mycobacterial disease in nonhuman primates as this agent can mimic MAC and related mycobacteria.
T he bacterium Mycoplasma bovis is an economically important pathogen of cattle that contributes ... more T he bacterium Mycoplasma bovis is an economically important pathogen of cattle that contributes to the multifactorial bovine respiratory disease complex. In addition to causing respiratory disease, this bacterium can cause polyarthritis, mastitis, otitis media, and a chronic pneumonia-polyarthritis syndrome, impacting beef and dairy cattle worldwide (1). Despite increased recognition of its role in economic loss in the cattle industry, M. bovis remains a clinical challenge because of a common carrier state in clinically healthy animals, variable disease expression, intermittent shedding, and the lack of rapid accurate diagnostic assays (1,2). Clinical disease is not considered necessary to maintain M. bovis in populations, and M. bovis is commonly detected in asymptomatic adult feedlot cattle (2). Although the upper respiratory tract mucosa is a primary site for M. bovis colonization, presence of the bacterium in the lung is variable in occurrence and clinical manifestation. In 1 study, M. bovis was detected in 46% of cattle with normal lungs, 82% of cattle with acute fibrinous pneumonia, and 98% of cattle with chronic pneumonia (3). Manifestation of M. bovis-associated respiratory disease is particularly common in the wake of stress (e.g., from transportation, comingling, feedlot entry, and harsh temperatures or conditions). In the early 2000s, M. bovis caused several highmortality (case-fatality rate 45%) epizootics in bison (Bison bison) in North America (4). These events raised concern about emergent virulent strains, and research began to characterize isolates from different host species (5). An important difference between outbreaks of mycoplasmosis in bison and cattle is that, in the former, few or no co-infecting bacterial or viral pathogens are consistently detected (4,6-8). Although M. bovis virulence factors are poorly defined, evasion of immune response is implicated in maintaining chronic infection (9). One study found that that up to 79% of bison herds in western Canada have >1 M. bovis-seropositive animal and that 8 of 11 herds with no history of M. bovis disease had seropositive animals (10). These findings suggest that host response to M. bovis varies; some exposed bison become subclinical carriers and might also
Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc, 2017
A 10-y-old Watusi ( Bos taurus africanus) steer housed at a drive-through game park in Winston, O... more A 10-y-old Watusi ( Bos taurus africanus) steer housed at a drive-through game park in Winston, Oregon developed severe clinical illness including fever, marked nasal discharge, injected scleral and conjunctival membranes, plus oral hemorrhages and erosions. The animal responded poorly to supportive treatment and was euthanized. Additional gross findings at postmortem examination included papules and erosive lesions on the tongue, hemorrhagic large intestine, and multifocal cardiac hemorrhages. Histopathologic findings included multifocal lymphoplasmacytic vasculitis plus fibrin exudation in heart and tongue. Total DNA obtained from the splenic samples was positive for alcelaphine gammaherpesvirus 1 (AlHV-1) as tested by a multiplex PCR for malignant catarrhal fever (MCF) viruses. The AlHV-1 detection was further confirmed by amplification and sequencing of a viral DNA polymerase gene fragment, which was identical to AlHV-1 sequences in GenBank. This was the first diagnosis of clini...
Highly pathogenic avian influenza (HPAI) is a major viral disease of poultry characterized by acu... more Highly pathogenic avian influenza (HPAI) is a major viral disease of poultry characterized by acute onset, systemic infection, and rapid death. In January 2015, H5N2 HPAI was identified by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and gene sequencing as the cause of rapid death in 40 of 390 ring-necked pheasants (approximately 10% mortality), raised in a game bird farm in Washington State. We report clinicopathologic findings and viral antigen distribution in pheasants that died during the outbreak. Affected birds were depressed with reluctance to move, ruffled feathers, and drooping heads. Congestion of the cerebellar meningeal blood vessels was the only consistent gross pathologic finding. Meningoencephalitis with vasculitis and necrosis in the spleen and heart were the major microscopic lesions in the birds. Viral antigen was consistently detected in the brain, heart, and ovary with variable presence in other organs.
Twenty-two feral rock pigeons (<i>Columba livia</i>) from 10 counties in California w... more Twenty-two feral rock pigeons (<i>Columba livia</i>) from 10 counties in California with ataxia, torticollis, and difficulty standing and flying were admitted to rehabilitation centers in late winter and spring of 2017 and died or were euthanized. Common necropsy findings included thin body condition, generalized deep red discoloration of organs, and hemorrhagic subcutaneous neck tissues. Meningoencephalitis was observed microscopically in 16 pigeons, and 3 also had protozoal schizonts in the brain. The most consistently affected regions of the brain were cerebellum and brainstem. Skeletal muscles, and less frequently the heart, contained large intrasarcoplasmic bradyzoites typically without inflammation. Fifteen of the 22 birds tested positive using pan-<i>Sarcocystis</i> polymerase chain reaction. The sequence of the amplicon was most closely related to <i>S. calchasi</i>, and the 8 subtyped sequences had 100% homology with <i>S. calchasi&...
Journal of zoo and wildlife medicine : official publication of the American Association of Zoo Veterinarians, 2015
A 17-yr-old female fallow deer presented with ataxia, inappetence, decreased fecal output, and de... more A 17-yr-old female fallow deer presented with ataxia, inappetence, decreased fecal output, and decreased mentation. A complete blood count demonstrated leukocytosis (24.1×10(3)/μl, n=1.16-7.38×10(3)/μl), characterized by lymphocytosis (22.89×10(3)/μl, n=0.18-3.65×10(3)/μl), anemia (packed cell volume 20%, n=29.0-55.8%), decreased red blood cell count (4.1×10(3)/μl, n=6.86-14.72×10(3)/μl), and decreased hemoglobin (7.5 g/dl, n=9.4-19.2 g/dl). Numerous mature, well-differentiated lymphocytes were noted on the blood film. Despite treatment and clinical improvement, the decision was made to euthanize the deer. Histopathology identified a monomorphic population of CD3 positive, CD79a negative small lymphocytes replacing most of the hematopoietic tissue in the bone marrow without evidence of tissue invasion. Results of viral screening were negative.
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Papers by Daniel Bradway