Cat parasites occur on marine mammals

Researchers at California Polytechnic University have discovered a clue explaining why the world's marine mammals are unable to withstand a parasite normally found only in cats. The study was presented at the 108th meeting of the American Society for Microbiology in Boston. The key to the problem may be just ordinary anchovies.

Toxoplasma gondii - a single-celled parasite that causes toxoplasmosis, ranks third among the leading causes of death related to food poisoning in the United States. The Centers for Disease Control and Prevention estimates that over 20% of the US population is infected with this parasite. However, its transmission form (zygote) is only found in cats.

In the past decade, toxoplasma has spread to many marine mammals including white whales, dolphins, sea lions and seals. This is also the main cause of death for sea otters living in coastal California. It is estimated that about 17% of sea otters die from toxoplasma. Many people believe that the flow of fresh water containing cat feces is the cause, but there is no definitive scientific conclusion about the source of infection.

Gloeta Massie, a graduate student who conducted the study with Professor Michael Black, said: 'The problem for our research is how to get mammals from the Arctic to Australia to be infected. infected by parasites that are replicated mainly through the destruction of cat feces and infected cat meat? Based on the prevalence of T. gondii infection, we hypothesize that migratory species have a feeding method by filtering food from the surrounding environment, especially the Northern anchovies , which are carriers. T. gondii travels all over the seas. '

Anchovy.(Photo: www.rockportflyfishers.com )

There are no previously published studies on the ability of anchovies to filter the zygote. So this is the first step to prove their hypothesis. Massie and Black exposed Northern anchovies to parasites, then used molecular techniques to check the presence of parasites in fish. They found that T. gondii's DNA appeared on 66% of the tested fish.

So they have shown that anchovies can filter invertebrates from water, the next step is to determine the infection of anchovies when exposed to mammals.

Massie said: 'Do you think the study's findings want to recommend that you stop eating anchovy piza? But it's not like that. Cysts of T.gondii are destroyed at high temperatures . Unfortunately, marine mammals cannot cook their food before eating. Anchovy is the prey for most carnivorous, mammal and bird species. So if anchovies contain pathogenic cysts, it could be the path of T. gondii transmission into the marine environment . '