Dear MARMAM readers We are pleased to announce two publications regarding the parasite *Toxoplasma gondii* in pinnipeds in Antarctica.
Short summary of the two papers: *Toxoplasma: a Cat-parasite in seals from Antarctica* * * *Toxoplasma gondii* is a protozoan parasite that causes the disease toxoplasmosis which is considered dangerous for pregnant women who have not had the disease before, or people with weakened immune systems. *Toxoplasma *is known worldwide and has also been part of the reason for increased mortality among sea otters in the United States. Members of the cat family are definitive hosts for this parasite, and play a key role in the epidemiology. *Toxoplasma *may be transmitted through food or water contaminated with oocysts (the resistant form of the parasite) from cat faeces, or via ingestion of infected meat with resting parasites in tissue cysts. Despite extensive worldwide surveillance in populations of both people and wildlife, little is known about *Toxoplasma gondii* ecology in the Antarctic region. Two recent studies, performed by scientists at the Norwegian School of Veterinary Science, The Sea Mammal Research Unit, the British Antarctic Survey and at the SALUVET group from Complutense University of Madrid in Spain, have investigated the presence of this parasite in Antarctic marine mammals. Different animal species, true seals and eared seals, from different locations were examined. In both studies, antibodies against *T. gondii* were found mainly in Weddell seals and Southern elephant seals whereas a small percentage of Antarctic fur seals were positive. Although antibodies have been found in seals in several studies from the arctic and worldwide, these studies are the first to document the presence of antibodies in seals from Antarctica. The study led by Pedraza-Díaz concluded that the differences observed between the animal species could be due to their different distribution and migratory ranges as well as their feeding habits. There is no wild felid fauna in Antarctica and in 1991 the Madrid Protocol on Environmental Protection to the Antarctic banned all introduced species, including cats, from the Antarctic to protect the native wildlife from introduced diseases. However, felids are present in the sub-Antarctic regions, areas within the normal distribution range of the animal species analysed here. High seroprevalence values have been reported in feral cats in the Kerguelen archipelago in the Sub-Antarctic region. Therefore exposure to * Toxoplasma* might have occurred outside Antarctica. This agrees with the higher detection rates in Southern elephant seals and Weddell seals found here, which show wider distribution and migratory ranges. Survival of infectious *Toxoplasma *oocysts in seawater has previously been demonstrated, suggesting that the oocysts can survive in the marine ecosystem of Antarctica. Since seal don’t drink water, contact through diet is the best way of explaining the exposure. When oocysts of the parasite come in contact with water, molluscs like shellfish, can filter these oocysts and possibly infect the animals that eat them. At least that was the conclusion from scientists in the United States who worked with sea otter mortality due to toxoplasmosis. In addition, recent studies in which anchovies were experimentally exposed to *Toxoplasma* oocysts have indicated that migratory filter feeder fish may play a role in the transmission of *T. gondii* in the marine environment. Macquarie Island is an island known for sealing, science and tourism. Feral cats have been known to inhabit the island since 1820s and have been eradicated since the late 1990s. Little is known about the marine pathway of Toxoplasma, and Jensen and her team suggest a marine pathway of * Toxoplasma* oocysts. Although the presence of *Toxoplasma* has not been investigated in the feral cats on Macquarie Island there is a possibility that oocysts have found their way from the island across the Antarctic conveyor belt and to Hutton Cliff where Weddell seals forage. Jensen has suggested a similar transmission for the Arctic ecosystem in a previous study where she found polar bear, ringed and bearded seals to be exposed to Toxoplasma. These findings are very interesting and show how little we know about the presence and transmission of *T. gondii *in the marine ecosystem. Further studies are needed to provide additional information regarding how *T gondii *may affect the Antarctic fauna. References: *Jensen, S.K*., Nymo, I.H., Forcada, J., Godfroid, J., Hall, A. (2012). Prevalence of *Toxoplasma gondii* antibodies in pinnipeds from Antarctica.Veterinary Record doi:10.1136/vr.100848 http://veterinaryrecord.bmj.com/content/early/2012/07/31/vr.100848.extract *Rengifo-Herrera, C*., Ortega-Mora, L.M., Álvarez-García, G., Gómez-Bautista, M., García-Párraga, D., García-Peña, F.J., Pedraza-Díaz, S. (2012), Detection of T*oxoplasma gondii* antibodies in Antarctic pinnipeds. Veterinary Parasitology doi: 10.1016/j.vetpar.2012.05.020 http://dx.doi.org/10.1016/j.vetpar.2012.05.020 For any questions or pdf requests please email: Silje-Kristin Jensen: s...@st-andrews.ac.uk Susana Pedraza Díaz: spedr...@vet.ucm.es Cheers Silje-Kristin Jensen and Susana Pedraza Díaz
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