UTS and Israeli scientists have developed a revolutionary concept and technique to meet worldwide consumer demand for drug-free chickens.

In collaboration with Dr Michael Wallach and his team from the veterinary pharmaceutical company Abic Ltd in Israel, UTS University Reader in Cell and Molecular Biology, Dr Nick Smith, and his co-researchers in the Faculty of Science Molecular Parasitology Unit have played a significant role in developing an effective and uniquely delivered vaccine against coccidiosis, a disease that poses a major threat to the global poultry industry, causing losses in excess of $1 billion annually.

The single-cell parasite called Eimeria, which causes coccidiosis, is probably the most numerous organism on earth. Eimeria has a complex life cycle with both asexual and sexual stages, and parasitic and "free living" forms. It is at the free-living oocyst stage that the parasite spreads prolifically from bird to bird.

Eimeria, which lives in the birds' intestines, either kills the chickens or causes severe diarrhoea, anaemia and weight loss, the latter resulting in smaller birds and smaller profits.

Until now, poultry farmers have used drugs known as ionophores to control coccidiosis. Consumer concerns about residual drugs in chicken meat have fuelled research worldwide to find healthy alternatives to drug therapy.

The UTS/Israeli collaborative effort has investigated successfully a unique approach to the problem - vaccinating breeding hens against coccidiosis so that the protective antibodies they develop can be passed on to their hatchlings via the egg yolk.

"We believe that the development of an effective maternally-delivered vaccine against coccidiosis will revolutionise the poultry industry worldwide. It will reduce chemical controls and costs significantly, and satisfy consumer demand for drug-free agricultural practices and residue-free meat," Dr Smith said.

A chicken starts laying eggs at 20 weeks of age and continues for about 30 weeks, producing five or six eggs weekly. Vaccinating a breeding hen would therefore protect 150 chickens raised for the meat market.

Currently a first-generation vaccine is produced by removing the intestines from chickens infected deliberately, purifying the parasite and isolating several proteins or native antigens, an expensive and lengthy process now used in Israel on a commercial scale.

Dr Smith and his team - Postdoctoral Fellows Dr Sabina Belli and Dr Michelle Gleeson, doctoral student David Witcombe and Research Assistant Caroline Teasdale - are conducting research aimed at replacing the native antigens that came directly from the parasite with recombinant antigens or proteins, a synthetic version based on DNA technology and molecular biology.

"We plan to conduct efficacy trials to determine whether our synthetic vaccine is as good as the native version and to ensure that the vaccine triggers the production of strong antibodies. Historically, recombinant proteins have varied in structure from the native versions and don't work as well, so decades of work have come undone at the very last step. We are hopeful that we won't have that problem.

"Any recombinant vaccine that works effectively against parasites would be regarded as a major step forward."

The research has also shed light on previously unknown features of the parasite's basic biology. "We are making exciting discoveries every day that tell us more about the molecular events and biochemistry of how the parasite transforms itself from one stage to the other," Dr Smith said.

"This research has important ramifications for Eimeria and for other important animal and human parasites including Cryptosporidium, Neospora, Toxoplasma and Plasmodium, which causes malaria.

"All these parasites go through similar transformations, crucial to their survival and transmission."

An Australian Research Council SPIRT grant has supported the research for the past three years, with additional funding from the Israeli company Abic Ltd and the Rural Industries Research and Development Corporation in Australia. Abic's Dr Wallach plans to visit the Gore Hill laboratory shortly.