What makes parasites so successful?

Parasites are smart, successful and winning the race against humans.

Parasites are remarkably successful - there are far more parasitic organisms than non-parasitic organisms in the world (even excluding fungal, bacterial and viral pathogens).

Worldwide there are few effective vaccines against parasites and chemical treatments are losing effectiveness as parasites build up resistance. In the race to overcome the enormous health and financial burden of parasitic infections - in both humans and livestock - it is the parasite that is winning.

More than any other creature parasites have:

• Enormous genetic plasticity. This allows them to alter their genetic makeup to develop resistance to the immune system, the environment or to chemicals aimed at eradicating them.
• Complex lifecycles which allows them to significantly alter their phenotype (characteristics) as they mature through their developmental stages.
• An ability to modify their gene expression and protein and metabolic profile to: resist an attack by the immune system of their host; adapt to the pressure of antiparasitic drugs; move from host to host, or host to the outside world.