Brad L Njaa

• BSc, DVM, MVSc DACVP
• Senior Pathologist at Greenfield Pathology Services

The objective of this work was to evaluate the safety and efficacy of a recombinant, subunit SARS-CoV-2 animal vaccine in cats against virulent SARS-CoV-2 challenge. Two groups of cats were immunized with two doses of either a recombinant SARS-CoV-2 spike protein vaccine or a placebo, administered three weeks apart. Seven weeks after the second vac...

CNS lesions associated with chronic otitis have not been reported in red kangaroos (Macropus rufus), to our knowledge. Here we describe an intracranial inflammatory polyp secondary to chronic otitis in a 6-y-old female red kangaroo with right auricular discharge, loss of balance, and head tilt. Autopsy highlighted a pale-yellow, firm, intracranial...

A 27-year-old female African grey parrot (Psittacus erithacus) presented as a referral for surgical removal of an enlarged uropygial gland that was first observed by the owner 6 months prior. Antibiotic therapy was attempted by the referring veterinarian with limited treatment response. No abnormalities were noted in the results of a complete blood...

Acute death of 1-month-old calves on pasture that were accidentally exposed to an oil/antifreeze mix were investigated. Clinical signs were not observed and necropsy findings were non-specific. Histological diagnosis of calcium oxalate nephrosis with concurrent tubulointerstitial suppurative nephritis was supported by culture. Ethylene glycol expos...

Gadolinium‐based contrast agents are used across species to better visualize abnormalities during MRI and are considered generally safe in clinical practice. The aim of this study was to investigate central nervous system (CNS) gadolinium deposition in 11 dogs that had an MRI performed, received 0.22 mL/kg (0.1 mmol/kg) of gadopentetate dimeglumine...

A 1-year-old, female intact crested gecko was evaluated because of skin discoloration on her ventrum. Full-thickness biopsies were taken and evaluated histologically. Multifocally and regularly, there were collections of birefringent, granular material, localized primarily to the most superficial dermis subjacent to the overlying epithelium, throug...

Background: An aural cholesteatoma, more appropriately named tympanokeratoma, is an epidermoid cyst of the middle ear described in several species, including dogs, humans and Mongolian gerbils. The cyst lining consists of stratified, keratinizing squamous epithelium with central accumulation of a keratin debris. This case report describes vestibul...

An aural cholesteatoma, more appropriately named tympanokeratoma, is an epidermoid cyst of the middle ear reported in several species, including dogs, humans and Mongolian gerbils . The cyst lining consists of stratified, keratinizing squamous epithelium with accumulation of keratin debris centrally. This report shows histopathological evidence of...

The ear is three anatomically defined but interconnected portions: the external ear, the middle ear, and the internal ear. The external acoustic meatus (EAM) is the bony and cartilaginous tube referred to as the external ear canal. It connects the external and middle ear. Neoplasms involving the internal ear include nerve sheath tumors of cranial n...

The purpose of this study was to establish microscopic normal in the middle ear of the cat while concurrently characterizing gross and microscopic lesions reflecting spontaneous otitis media. Both ears from 50 cats were examined grossly and processed for histologic examination of the external, middle, and internal ear on a single slide. Gross lesio...

The efficacy of orally administered therapeutics for the treatment of cantharidin intoxication has not been evaluated in controlled studies. To develop a model of acute cantharidin intoxication in laboratory rats and to evaluate in this model the relative efficacy of 3 gastrointestinal therapies used to treat equine cantharidin toxicosis. Sixty-fou...

Plants of the genus Taxus are common ornamental shrubs that contain cardiotoxic alkaloids. Gross lesions consistent with heart failure are frequently reported in fatal cases; however, microscopic lesions in the heart have not been well characterized. The current report describes 2 related outbreaks in which 7 of 30, 250-kg calves died after confirm...

The purpose of the gross necropsy examination of the gastrointestinal tract is to recognize the presence of lesions, thus requiring a basic understanding of its normal appearance and anatomy. This article highlights gross changes to the gastrointestinal tract of adult cattle that help place the disease processes into broad categories. Although few...

Most veterinary textbooks provide very little guidance regarding ear sampling, processing, and examination. The complexity of the ear, which includes integument, mucosa, cartilage, bone, and neural tissues, and the special procedures required to allow histologic examination are 2 of the more common reasons for reluctance by clinicians and pathologi...

Knowledge of the normal structure and function of the canine and feline ear is critical to be able to diagnose abnormalities that either involve the ear or originate within one or more of the ear compartments. In addition, a veterinarian must be aware of various structures within or associated with the ear so that they are not damaged or destroyed...

This article reviews post-mortem examination, sample collection, and diagnostic procedures used to determine the cause of abortion, stillbirth, and neonatal death in dogs and cats.

Kirkbride's Diagnosis of Abortion and Neonatal Loss in Animals, Fourth Edition is a concise resource for determining the causes of abortion and neonatal loss in cattle, small ruminants, pigs, horses, dogs, cats, and exotic mammals. Presenting current procedures for diagnosing abortion, this classic reference has been fully updated and expanded, off...

IntroductionBackground prediagnosticsDiagnostic investigationTopics of special consideration

Pseudorabies is caused by Suid herpesvirus 1, a member of the Alphaherpesvirinae subfamily. Although pigs are the natural host of Pseudorabies virus (PRV), the virus has a broad host range and may cause fatal encephalitis in many species. The United States obtained PRV-free status in 2004 after the virus was eradicated from domestic swineherds, but...

The NS1 protein of human influenza A viruses binds the 30-kDa subunit of the cleavage and polyadenylation specificity factor (CPSF30), a protein required for 3′ end processing of cellular pre-mRNAs, thereby inhibiting production of beta interferon (IFN-β) mRNA. The NS1 proteins of pathogenic 1997 H5N1 viruses contain the CPSF30-binding site but lac...

Rupture of abdominal artery aneurysm (AAA) in cattle is sporadic and typically affects adult Holstein dairy cows. In this retrospective study, liver concentrations of copper (Cu), iron (Fe), manganese (Mn), sulfur (S), and zinc (Zn) were evaluated using inductively coupled plasma atomic-emission spectroscopy. Up to three liver sample types (fresh/f...

List of Cases (ID, Species, Submitter) #1 09060055, Buff Orpington chicken, Adam W. Stern and Bradley L. Njaa (US) #2 G08-1544, Moluccan cockatoo, Michael Garner (US) #3 AVD07-525, prairie dog, Madeline Rae (US) #4 AVD09-136, African pygmy hedgehog, Madeline Rae (US) #5 Eclectus parrot, David N. Phalen (AU) #6 Asian dormouse, Gerry M. Dorrestein an...

C-KIT is the cellular homolog of the feline sarcoma viral oncogene v-KIT, which encodes the tyrosine kinase receptor protein KIT. Mutations and varied expression of this gene have been demonstrated within multiple neoplasms in people and domestic animals. The purpose of this study was to determine if KIT protein is expressed in feline soft tissue f...

Previous studies showed that a considerable proportion of Listeria monocytogenes isolates obtained from foods carry a premature stop codon (PMSC) mutation in inlA that leads to production of a truncated and secreted InlA. To further elucidate the role these mutations play in virulence of L. monocytogenes, we created isogenic mutants, including (i)...

In 2004, the isolation of an influenza virus from racing greyhounds changed the point of reference for discussions about influenza virus in dogs. A virus isolated from greyhounds did not have its origin in a previously described human influenza virus but came from a virus with an equine history. More significantly, evidence emerged to indicate that...

Few viral pathogens resulting in encephalitis in dogs and cats have emerged over the past decade or so. All are the result of penetration through presumed species barriers and all are considered zoonoses or possible zoonotic pathogens. In all cases, encephalitis is a rare event that has low morbidity but high mortality. More viruses are likely to e...

"Lyme nephritis" is a poorly characterized condition associated with proteinuria and often fatal renal failure in dogs with serological evidence of infection with Borrelia burgdorferi. The aim of this study was to determine if intact B. burgdorferi organisms were present in the kidneys of serologically Lyme-positive dogs with histopathologic featur...

Squamous-cell carcinoma (SCC) is the second most common tumor in horses, and 40%-50% may occur in ocular and adnexal structures. Cyclooxygenase (COX)-2 is an inducible enzyme responsible for the production of prostaglandins that control cell growth and the development and progression of cancer. Mechanisms responsible for the initial upregulation of...

Dozens of red, raised nodules scattered along the serosal surface of the small intestine and the right and left ovaries were observed as incidental findings on gross examination in a 21-year-old Thoroughbred mare euthanatized for severe lameness. Histologically, these nodules were composed of numerous, variably sized, redundant vascular profiles fi...

In this retrospective study, the authors describe the gross and histologic changes associated with rupture of an abdominal artery aneurysm in 33 mature female Holstein cattle between January 1980 and June 2005 from 29 farms in upstate New York and northern Pennsylvania. Over this period, there was an increase in the number of cases submitted for ne...

To evaluate factors associated with survival in dogs with nasal carcinomas that did not receive treatment or received only palliative treatment. Retrospective case series. 139 dogs with histologically confirmed nasal carcinomas. Medical records, computed tomography images, and biopsy specimens of nasal carcinomas were reviewed. Only dogs that were...

A 23-year-old, 467-kg Palomino mare was examined for evaluation of sudden onset severe ataxia and depression. The mare had been found down in a pasture and was unable to rise. She was observed, by her owner, to be normal 24 hours earlier. This mare had resided with this owner for approximately 1.5 years, had always lived out on pasture, and had exp...

Contributions of the alternative sigma factor σB to Listeria monocytogenes infection were investigated using strains bearing null mutations in sigB, prfA, or inlA or in selected inlA or prfA promoter regions. The ΔP4inlA strain, which has a deletion in the σB-dependent P4inlA promoter, and the ΔsigB strain had significantly reduced invasion efficie...

This report describes a 3-year-old male castrated Mastiff dog that died unexpectedly with locally extensive, acute, necrotizing myocarditis and myocardial infarction. Intralesional protozoal tachyzoites in the affected myocardium were confirmed to be Neospora caninum by a novel multiplex polymerase chain reaction (PCR) and immunohistochemistry. Pro...

Twenty-one rejected kidneys from 2426 slaughtered dairy cows (0.87 per cent) had gross signs of pyelonephritis that were confirmed by histopathology. In all the kidneys the findings were consistent with a chronic rather than an acute infection. One species of bacteria was cultured from 12 of the kidneys and two species of bacteria were cultured fro...

Uremic gastritis is a term commonly used to describe the gastrointestinal signs and histopathologic changes associated with renal failure in the dog. This retrospective study reviews the clinical, serum biochemical, and postmortem histopathologic data from 28 dogs with renal failure to determine the prevalence of gastric histopathology, characteriz...

In chickens infected with virulent (v) or very virulent (vv) Marek's disease (MD) virus (MDV) strains, small to moderate increases in plasma nitric oxide (NO) levels are seen, respectively, whereas very virulent plus (vv+) strains induce very high levels in vivo. The data presented in this report show that chickens presenting with clinical neurolog...

A 6-year-old, castrated male, mixed-breed dog was diagnosed with partial unilateral ureteral obstruction secondary to a ureteral mass. The ureteral mass was surgically resected, and an ureteroneocystostomy was performed. Histopathology of the ureteral mass was consistent with a poorly differentiated mast cell tumor (MCT). The patient recovered well...

Skeletal muscle samples from 38 draft horse-related animals 1-23 years of age were evaluated for evidence of aggregates of glycogen and complex polysaccharide characteristic of equine polysaccharide storage myopathy (EPSSM). Cardiac muscle from 12 of these horses was also examined. Antemortem serum levels of creatine kinase (CK) and aspartate amino...

The objective of this study was to evaluate the efficacy of immunohistochemical (IHC) staining for diagnosis of persistent bovine viral diarrhea virus (BVDV) infection using formalin-fixed, paraffin-embedded skin biopsy specimens. Skin from 41 of 42 calves shown to be persistently infected (PI) with BVDV by repeated virus isolation more than 3 week...

Three cats with indolent corneal ulcers and one cat with bilateral corneal sequestration and normal aqueous tear production were found to have rapid tear break-up times (BUTs). Tear BUTs in clinically affected cats averaged 2.5 +/- 1.29 s and 2.33 +/- 0.58 s for the right and left eyes, respectively. Palpebral conjunctival biopsies were harvested f...

The present studies were carried out to compare the low density lipoprotein (LDL) metabolism by freshly isolated immature porcine granulosa cells with that by luteal cells. Furthermore, we have examined the effect of serum used for plating of granulosa cells on lipoprotein degradation and utilization. In incubation studies, addition of LDL as an ex...