Disseminated Neosporosis in a dog

Disseminated Neosporosis in a dog

History: A 6 week-old intact female Boxer became non-ambulatory with decreased or absent hind limb reflexes.  Forelimb and cranial nerve reflexes were normal.  A Neospora titer was positive.   There was acute onset of hind limb paresis in 3 out of 6 puppies in the litter.

Gross Pathology:  None


Spinal cord:  Diffusely throughout the spinal cord the spinal nerves and

ganglia are multifocally infiltrated  by moderate numbers of lymphocytes,

macrophages,  eosinophils and neutrophils with occasional protozoal

cysts consistent with Neospora caninum or Toxoplasma gondii.  The

cysts measure 30-40 micron in diameter and contain numerous 2 X 4

micron zoites. There are multifocal areas of necrosis and gliosis in the

grey and white matter of  spinal cord.

Spinal cord with spinal nerves: There is infiltration of the ventral spinal nerves with large numbers of inflammatory cells (photo courtesy of Dr Janardhan)

Spinal nerve: The nerve is infiltrated by large numbers of lymphocytes with eosinophils and neutrophils

Brain:  In all parts of the brain, but more prominently in the midbrain and

brainstem,  there are multifocal areas of necrosis and gliosis with

occasional protozoal cysts in the neuropil,  glial cells, or neurons.   The

brain stem contains a bilaterally symmetrical area of neuronal necrosis

characterized by cell shrinkage, loss of nuclear detail, and

hypereosinophilia.  There is central chromatolysis and peripheralization of

the nucleus in some neurons.

Brain: There are multiple focal areas of neuropil loss with clusters of glial cells mixed with some mononuclear cells (Photo courtesy of Dr Janardhan)
Brain: Multifocal neurons are shrunken with pyknotic nuclei

Brain: Protozoal cysts were found within some cells

Sciatic nerve:  There are multifocal interstitial infiltrates of eosinophilis,

lymphocytes, and macrophages.

Sciatic nerve: Lymphocytes, eosinophils, and neutrophils infiltrate the epineurium and perineurium

Heart and skeletal muscle:  There are multifocal interstitial infiltrates of

lymphocytes, macrophages, and a few eosinophils in the appendicular

skeletal muscle, glossal skeletal muscle, and myocardium.

Heart: The myocardium is infiltrated by multifocal aggregates of lymphocytes and plasma cells

skeletal muscle: There are multifocal aggregates of lymphocytes, plasma cells and macrophages


1.  Spinal nerves and ganglia: Polyradiculoneuritis and ganglionitis,

lymphocytic and eosinophilic, with intralesional protozoal cysts.

2.  Brain and spinal cord: Encephalomyelitis, lymphocytic, histiocytic,

eosinophilic  multifocal, moderate with intralesional protozoal cysts.

3.  Sciatic nerve: Neuritis, eosinophilic and lymphocytic, multifocal,


4. Skeletal muscle,(appendicular, epaxial and glossal): Myositis,

multifocal, moderate, lymphocytic and eosinophilic

5. Heart: Myocarditis, lymphocytic, eosinophilic, multifocal, moderate


Neospora cannot be differentiated from Toxoplasma by light microscopy. Diagnosis of neosporosis is based on the positive serology for Neospora caninum and supportive histopathologic findings.

Read more on VSPO:

Neosporosis in a dog:    Brain and skeletal muscle,   skin

About Brian

Anatomic Pathologist, VetPath Services, Stone Ridge, NY- musculoskeletal, oral/dental, and sinonasal diseases www.vetpathservices.com
This entry was posted in Necropsy Cases and tagged , , , . Bookmark the permalink.

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s