11.   Since the acute disease occurs within the prepatent period, eggs of Oesophagostomum spp. are not usually present in the faeces.

12.   Although infectious diseases occur primarily in less developed countries, they are on the rise in the United States, Tarleton said.

13.   Autoimmune disease occurs when the immune system, which normally defends the body against infection, instead turns those defenses against its own cells and tissues.

14.   Autoimmune diseases occur when the immune system malfunctions and attacks the body in the same way it fights invading bacteria and viruses.

15.   Because the disease does not occur in the United States naturally, testing and manufacturing a vaccine will be tricky both ethically and financially.

16.   Doctors long believed the disease occurred only during middle age or later.

17.   Guinea worm disease occurs when people drink water containing tiny water fleas that have ingested microscopic Guinea worm larvae.

18.   He discusses why the disease occurs twice as frequently in women and what its relationship to violence may be in men.

19.   India and Brazil have severe leprosy problems, but the disease occurs almost everywhere in the world.

20.   Most diseases occur when a pathogen or a gene defect causes a cell to make aberrant proteins.