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Cerebral Baylisascaris larva migrans in a cynomolgus macaque (Macaca fascicularis)
1Pfizer Drug Safety Research and Development, 455 Eastern Point Road, MS 8274-1221, Building 274, Office 1703F, Groton, CT 06340, USA.
Abstract:
An incidental, asymptomatic, focal inflammatory lesion was detected in brain cerebrum of an approximately 6-year-old, female cynomolgus macaque from a chronic toxicology study. No gross lesions were noted at necropsy. Microscopically, the lesion contained a cross-section of larvae approximately 70-80 μm in diameter, a centrally located intestine flanked on either side by large triangular excretory columns, and prominent single lateral cuticular alae. Mixed inflammatory cells of eosinophils, macrophages, and lymphocytes admixed with abundant connective tissue stroma and necrosis surrounded the larvae. Histochemical stains for trichrome revealed significant amount of fibrous connective tissue. The morphology of the larvae was compatible with Baylisascaris spp. Based on the microscopic and histochemical examination, a diagnosis of neural Baylisascaris spp. larva migrans was made.
Insights
A Baylisascaris spp. larva was found in the brain of a cynomolgus macaque, causing an inflammatory lesion. This diagnosis of neural larva migrans highlights potential parasitic risks in non-human primates.
Area of Science:
- Veterinary Pathology
- Parasitology
- Primate Research
Background:
- Chronic toxicology studies in non-human primates are crucial for drug development.
- Incidental findings during necropsy can reveal unexpected health issues.
- Parasitic infections can present asymptomatically, complicating diagnosis.
Purpose of the Study:
- To identify and characterize an incidental inflammatory lesion found in the brain of a cynomolgus macaque.
- To determine the etiological agent responsible for the observed neuropathology.
- To report a case of neural larva migrans in a non-human primate model.
Main Methods:
- Necropsy and gross examination of the cynomolgus macaque.
- Microscopic examination of brain tissue, including histochemical staining (trichrome).
- Morphological analysis of detected larvae to identify species.
Main Results:
- An asymptomatic, focal inflammatory lesion was identified in the cerebrum.
- Microscopic examination revealed Baylisascaris spp. larvae (70-80 μm diameter) with characteristic morphology.
- Inflammatory infiltrate (eosinophils, macrophages, lymphocytes) and fibrous connective tissue surrounded the larvae.
Conclusions:
- The lesion was diagnosed as neural Baylisascaris spp. larva migrans.
- This finding underscores the importance of thorough histopathological examination in toxicology studies.
- Baylisascaris spp. should be considered in the differential diagnosis of brain lesions in non-human primates.
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