Number and virulence of the parasites that a host organism harbours
Parasite load is a measure of the number and virulence of the parasites that a host organism harbours. Quantitative parasitology deals with measures to quantify parasite loads in samples of hosts and to make statistical comparisons of parasitism across host samples.
High parasite load. Lappet moth caterpillar parasited by braconid wasps.Enumeration of Plasmodium parasites (blue) in human red blood cells (pink) to quantify relative parasite load.
^Thornhill, Randy et al. Zoonotic and Non-zoonotic Diseases in Relation to Human Personality and Societal Values: Support for the Parasite-Stress Model. Evolutionary Psychology, 2010. 8(2): 151-169