Friday, September 10, 2010
Here is the last puffer update - still no obvious cause. Very interesting.
We are now nearing the 100 mark for fish examined, and I'm afraid at this stage, we are no closer to determining what is causing this mortality. To recap,
What we have found.
1) Gross and microscopic pathology: We have examined 96 puffers >95% of which are A. hispidus with a sprinkling of meleagris, diodon hystrix, and C.
jactator. Histopathology is completed for 22 fish and the remainder are pending. Available data suggestive of virus or toxin.
2) Two separate attempts to isolate viruses from fish in two separate labs have been unsuccessful. Electron microscopy has failed to reveal presence of viral particles. Molecular virology assays at Washington University are pending.
3) Five separate field investigations (day and night dives around Oahu) have revealed occasional sick puffers but no clues to underlying cause of mortalities/sickness.
4) Based on above, we now have a decent understanding of the potential pathophysiology of why puffers are showing up dead and floating (uncontrolled inflation of swim bladder) and a potential explanation for why they are occasionally found attached to each other on surface (potential mating pairs).
The easy answers and approaches to arrive at cause of death have largely been exhausted. We will now be sifting for additional clues using available archived samples (for example closer scrutiny and cataloguing of stomach contents and systematic quantification of organ lesions).
We will also continue responding to sick and dying fish from all islands and cataloguing reports of dead fish.
Finally, at this stage, it is appropriate to extend a big Mahalo to all of those out there who are providing reports, and importantly, those on neighbor islands who are taking considerable time and energy to respond to events and ship samples to Oahu.
Thierry M. Work
Wildlife Disease Specialist
PO Box 50167
300 Ala Moana Blvd. Room 5-231
Honolulu, HI 96850, USA
tel: 808 792-9520
Fax: 808 792-9596
Posted by HIMB CEP at 10:51 AM