Parasitic infection trigger

Rise in sea-level and temperature during the Holocene period (which began 11,700 years ago) lead to an increase in parasitic infections in molluscs. This has emerged from a study of mollusc fossils of the period. Similar changes in sea level and temperature, which are likely in foreseeable future, can infect molluscs again. And this time, the infection can spread to humans who eat clams and snails. About 56 million people globally suffer from food-borne parasitic infections. 

Source

Down To Earth, February, 2015