A parasitic malady is a communicable disease caused or transmitted by a parasite. Several parasites don't cause diseases. Parasitic diseases will have an effect on all living organisms, as well as plants and mammals. The study of parasitic diseases is named parasitology.
Symptoms may mimic anemia or a hormone deficiency. Parasites are responsible for many ill health conditions including diarrhoea, gastrointestinal upset, vaginal irritation, joint pain, nervous diseases, immune dysfunction and chronic fatigue. Long term, undetected infestation can cause many systemic problems.
In Australia, between 1921 and 1995, death rates from infectious diseases declined faster than deaths from all causes. Age-standardised death rates from infectious diseases fell from 185 per 100,000 populations in 1921 to six in 1995. Over the same period, standardised death rates from all causes fell from 1,567 per 100,000 to 645. As a proportion of all deaths, infectious diseases declined from 19% in 1921 to 1% in 1995.