Some allergies are triggered by a disease[1]. It is possible that hayfever is an outcome of a disease which has become common since 1819. The disease may hav

Some allergies are triggered by a disease[1]. It is possible that hayfever is an outcome of a disease which has become common since 1819. The disease may have no other symptoms, and hay fever a symptom in only some people, and therefore be very hard to track. [1]: https://www.cdc.gov/media/releases/2023/p0727-emerging-tick-bites.html https://www.cdc.gov/media/releases/2023/p0727-emerging-tick-...