Caring for Stranded Marine Animals
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Marine Mammal Parasite of the Month – Case February 2012

Our second case is another marine mammal classic.  I was surprised when I first started looking at these parasites how much I had heard about them and how little I knew about their biology, pathology, and natural history.   Speaking of history…. A common dolphin was found dead on beach with no external injuries.  On necropsy, the ptergoid sinus was filled with these parasites.

Here is a closer look.  The black marks are 1mm each.

Further identification requires examination of internal structures, which is traditionally accomplished by clearing, staining, dehydrating, and mounting.  As I am more veterinarian then parasitologist, I opted to turn the specimens into biopsy samples and had them processed into standard H&E 5um slides.  Here is a full worm spread out on a composite digital micrograph.

What is the parasite?

How does it relate to the stranding?

How would you diagnose the infection with a dolphin in rehabilitation?

enjoy . . .


  1. I’ve looking for a simile brain parasite in stenella coeruleoalba brain. If you want I send you a photo

  2. The clues tell me this is Nasitrema. Nasitrema can migrate from the sinuses into the brain causing brain lesions that can result in neurological symptoms such as swimming in tight circles. Diagnosis can be through identification of ova in blowhole swabs or feces.

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