In some sense Ramanujan's mathematical research was also interrupted by a WW1. For example in http://rsnr.royalsocietypublishing.org/content/48/1/107 (Ramanujan’s illness, by D.A.B. Young) we read:

> These intentions were frustrated by the outbreak of war within four months of his arrival in England. Contact with much of continental mathematics abruptly ceased, and soon many Cambridge mathematicians, most significantly Littlewood, left on war service.

> Another consequence, slower in impact but more serious for Ramanujan’s well being, was food shortages, especially of Indian comestibles. He was a Brahmin Hindu and a strict vegetarian, and although in coming to England he had com­promised certain Brahminical strictures including crossing the seas, he remained punctilious about dietary observance. In the absence of another Brahmin to cook for him, he had to buy and cook all his food. If he had established a routine in his life, he could have coped. But he was obsessional about his research, working for 30 hours at a stretch and then sleeping for 20. ‘Cooking only once a day or two’, as Alice Neville remembers his habit , must have resulted in malnutrition.

Also from the book http://www.springer.com/us/book/9783319255668 (My Search for Ramanujan, by  K. Ono, A.D. Aczel):

> Another reason why Hardy failed in his attempt to have Ramanujan elected a Fellow of Trinity College had to do with World War I... Hardy was opposed to war, even while he understood the necessity to defend Britain and the Continent from German aggression ... Then at some point during the war, he supported antiwar statements made by the eminent Cambridge logician Bertrand Russell, and that was enough to tar him with the pacifist brush. He was thus politically weakened and could not effectively fight for Ramanujan.

> Ramanujan, humiliated and upset by the defeat of his nomination to become
a fellow, also suffered physically. It was at this point that the wartime scarcity of fresh fruits and vegetables—the main staples of his vegetarian diet—began to affect his health adversely. He became desperately ill. Naturally heavy, he now lost weight. He talked less, even meeting his only main contact with the world, Hardy, less frequently.