Sex used as weapon against parasites

A parasite that can clone itself and change sex in order to reproduce rapidly could have this remarkable ability used against its species as a result of research at James Cook University.


The research is being led by Professor Nick Smith, a Tropical Leader at the Queensland Tropical Health Alliance Laboratories at JCU's Cairns campus, the National Convenor for the Australian Network for Parasitology and Programme Leader at two of JCU's research centres, The Centre for Biodiscovery and Molecular Development of Therapeutics and The Centre for Biosecurity in Tropical Infectious Diseases.


Professor Smith and colleagues at the University of Zurich, in Switzerland, and the National Institute of Health, in Washington, have recently been awarded an international grant to fund their research.


"Our research aims to halt the sex life of some extremely adaptable parasites, the Apicomplexa," he said.


"These single-celled organisms affect hundreds of millions of people every year, especially in the tropics, and are deadly for a huge variety of animals including cattle, sheep, poultry and wildlife.


"They also infect humans, and cause several important diseases such as malaria, cryptosporidiosis and toxoplasmosis.


"These parasites can cause fever, anaemia, diarrhoea, stillbirth, growth and mental retardation, blindness, encephalitis, convulsions, coma and death."


Professor Smith will discuss his research at the free public lecture 'Parasites: How they breed and how we can stop it' at Rydges Tradewinds in Cairns on October 19.


He said parasites were supremely adaptable and successful, with far more parasitic organisms than non-parasitic organisms in the world.


"More than any other creatures, parasites have an enormous genetic plasticity," he said.


"This allows them to alter their protein and metabolic profile to adapt to attacks by the immune system of their host, resist anti-parasitic drugs and chemicals, move from host to host, and survive in hostile environments.


"The Apicomplexa group of parasites has taken this adaptability to extremes. The key to their adaptability and success is that they can reproduce very rapidly by cloning themselves, and they can also undergo a remarkable transformation to turn themselves into male and female cells and reproduce sexually.


"However, this strength is also their potential Achilles heel as there are only a certain number of ways to succeed at sex and we are researching how to halt it."


'Parasites: How they breed and how we can stop it' is part of a series of free public lectures by the Faculty of Medicine, Health & Molecular Sciences. Refreshments will be served at 5pm with the presentation starting at 6pm in the Trinity Room at Rydges Tradewinds in Cairns.


Information for media:

Professor Nick Smith can be contacted on Ph 4042 1315 or email/nicholas.smith)(



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