Rheumatoid arthritis (RA) patients who had the disease's symptoms in winter or in spring have more severe outcomes at six months, than those whose symptoms first appeared in summer, says study.

The researchers measure the severity of RA by the modified Total Sharp Score, mTSS, an assessment of erosion and joint space narrowing.

In addition, the patients' mTSS after six months showed poorer radiographic outcome if their first symptoms had occurred in winter versus autumn as the reference season.

Swine influenza (also called swine flu, hog flu, and pig flu) is an infection of a host animal by any one of several specific types of microscopic organisms called "swine influenza virus". In 2009 the media labeled as "swine flu" flu caused by 2009's new strain of swine-origin A/H1N1 pandemic virus just as it had earlier dubbed as "avian flu" flu caused by the recent Asian-linage HPAI (High Pathogenic Avian Influenza) H5N1 strain that is still endemic in many wild bird species in several countries.