COURTESY BY: https://www.dawn.com/ Ongoing illness after infection with Covid-19, sometimes called “long Covid”, may not be one syndrome but possibly up to four causing a rollercoaster of symptoms affecting all parts of the body and mind, doctors said on Thursday. In an initial report about long-term Covid-19, Britain’s National Institute for Health Research (NIHR) said one common theme among ongoing Covid patients — some of whom are seven months or more into their illness — is that symptoms appear in one physiological area, such as the heart or lungs, only to abate…