the latest incident comes days before us secretary of state antony blinken is due to visit the country. with me to discuss what we know about the situation is bbc�*s security correspondent, gordon corera. gordon, first of all, what is havana syndrome?— gordon, first of all, what is havana s ndrome? ~ . , , ., syndrome? well, the answer is that it's a mystery. _ syndrome? well, the answer is that it's a mystery. is — syndrome? well, the answer is that it's a mystery, is the _ syndrome? well, the answer is that it's a mystery, is the truth. - syndrome? well, the answer is that it's a mystery, is the truth. it's - it's a mystery, is the truth. it's an affliction which has hit us diplomats and spies, starting in cuba in 2016, hence the name havana syndrome, in which those people often felt a pressure or pain in their head, headaches, disturbances, sometimes very long lasting symptoms, which were debilitating. often a noise, as well. first of all in cuba, but then cases in china a year or two later, and since then, they have been at least 200 reports, accelerating in the last few mont