Despite the clear arguments for controlling parasitic infections, we know surprisingly little about the developmental processes in parasitic nematodes. A good model system for research is provided by Oesophagostomum dentatum, a roundworm which infects the large intestines of pigs, slowing the animals' growth and leading to significant economic losses. A number of chemicals are available to help keep the parasite in check but the worms are growing increasingly resistant to their use and so there is a substantial need for new methods of treatment.
From eggs to parasites
The worm, Oesophagostomum dentatum, has a fairly simple life cycle. Eggs appear in the faeces around 3 weeks after ingestion of third-stage larvae, the so called L3 stage larvae. In the first two developmental stages, the larvae are not infective. The third-stage larvae migrate from the faeces into the surroundings, where they can again be ingested by pigs. When the parasite reaches the large intestine, the third-stage larvae burrow into the mucosal layer of the intestinal wall and moult to fourth-stage larvae. After a further 6-17 days they emerge from the mucosa and undergo a final moult before they mature into adults and reproduce.
Drug screen on worm proteins
Together with colleagues in Australia and the USA, Martina Ondrovics in the group of Anja Joachim at the University of Veterinary Medicine, Vienna (Vetmeduni) has undertaken a detailed in vitro investigation of the proteins involved in the transition from third-stage to fourth-stage larvae. The researchers employed an integrative approach that combined in vitro drug testing with proteomic and bioinformatic analysis. Previous work had identified a number of enzymes (hydrolases) that are likely to have a role in parasite development. Ondrovics used sophisticated techniques to examine the effects of certain compounds (enzyme inhibitors) on the larval protein composition.
|Contact: Martina Ondrovics|
University of Veterinary Medicine -- Vienna