Last week I attended a symposium hosted by Massey University’s Infectious Diseases Research Centre (IDReC). There were many fascinating talks but one that caught my attention was by Dr Wendi Roe, a veterinary pathologist, about her work on Hector’s dolphins.
Hector’s dolphins are an endangered species living off the coast of New Zealand. [A 2010/2011 survey found only 55 adults remaining. – Edit 17/9/14 oops, that’s Maui’s dolphins. There are about 6000 Hector’s dolphins…] Dr Roe has been looking at causes of death in Hector’s dolphins and her results were surprising; 7 of the 28 she examined had evidence of extensive infection with the parasite Toxoplasma gondii (1).
If you need reminding, T. gondii is the parasite that makes mice lose their fear of cats, and has been associated with the development of schizophrenia, depression and suicide in people (2).
So how on earth are dolphins getting toxoplasmosis?! Dr Roe speculated that the parasite may be getting into the marine environment after being shed in cat poo. She is now wanting to do a study to see if the parasite can be found in filter feeders like mussels and from her pilot data it looks like the answer is yes. This isn’t the first evidence of marine animals being exposed to T. gondii – a survey of sea otters in California found that 42% had antibodies to T. gondii.
1. Roe WD, Howe L, Baker EJ, Burrows L, Hunter SA (2013). An atypical genotype of Toxoplasma gondii as a cause of mortality in Hector’s dolphins (Cephalorhynchus hectori). Vet Parasitol. 192(1-3):67-74. (doi: 10.1016/j.vetpar.2012.11.001)
2. Henriquez SA, Brett R, Alexander J, Pratt J, Roberts CW (2009). Neuropsychiatric Disease and Toxoplasma gondii Infection. Neuroimmunomodulation 16:122–133 (DOI: 10.1159/000180267)