"Cause of Sea Lion Deaths Still Unknown. This is the sixth in a series of written updates on the New Zealand sea lion mass mortality event. The updates will be issued by the Department of Conservation on a regular basis as new information comes to hand, and will also be available on its website, "www.doc.govt.nz".
The cause of the deaths of the threatened New Zealand sea lions is still unknown, the Department of Conservation says.
DOC spokesperson Mike Donoghue said preliminary results from the Institute of Virology at Erasmus University in Rotterdam, The Netherlands, had been received. The tests proved negative for seal herpes viruses, and are, so far, inconclusive for other types of viruses known to affect seals, including morbilliviruses. The lab will need another 4-6 weeks before any definitive conclusions could be drawn.
Investigations at Massey University's Cetacean Investigation Centre into the cause of the mystery deaths were continuing. Some strains of pathogenic bacteria, including several kinds of Salmonella, had been found in samples. "No single bacterium identified in the test results to date is a strong candidate for causing all the observed deaths."
DOC and Massey University are sending further samples to The Netherlands and may consider other overseas laboratories.
The mystery disease has killed at least 53 percent of this year's pup production (over 1600 pups) and is estimated to have killed at least 20 percent of the adult population. The total loss of adult female sea lions could not be estimated with confidence until at least the next breeding season in December and, possibly, until three years of pup production had been monitored." [It is interesting to note that the veterinarians at the Massey University have not, apparently, posted the gross and histological lesions presumeably noted in the various sea lions delivered to them. There seems to have been a consensus that the widespread deaths were due to an infective agent. Would it be possible for someone in the know to share with us what the lesions were, how various conditions were ruled out, and the reasons for searching for an infective cause. -- Mod.MHJ].--Martin Hugh-Jones <mehj2020@vt8200.vetmed.lsu.edu> via ProMED-mail <promed@usa.healthnet.org>