ISOLATION OF A FLAVIVIRUS RELATED TO THE TICK-BORNE ENCEPHALITIS COMPLEX FROM HUMAN CASES IN SAUDI-ARABIA

A flavivirus related to the tick-borne encephalitis complex was isolat ed from the blood of 6 male butchers, aged 24-39 years, in Jeddah, Sau di Arabia in November and December 1995. Two of the patients died and the other 4 recovered completely. Four more patients, 3 males and 1 fe male, were diagnosed serologically by immunoglobulin M capture enzyme- linked immunosorbent assay and seroconversion in acute and convalescen t blood samples examined by indirect immunofluorescent test using Vero cells infected with the isolated virus. The virus identity was confir med at the Centers for Disease Control and Prevention, Fort Collins, C olorado, USA, by the polymerase chain reaction; it was closely related to Kayasanur Forest disease virus. All infected patients had similar clinical and laboratory symptoms and signs, including fever, headache, generalized body aches, arthralgia, anorexia, vomiting, leucopenia, t hrombocytopenia, elevated liver enzymes (serum glutamic oxalacetic and serum glutamic pyruvic transaminases), elevated creatinine phosphokin ase, and elevated blood urea. One patient developed symptoms of enceph alitis, but survived without any sequel. Skin rash developed in 2 pati ents, morbilliform on the hands, feet, and lower abdomen of one patien t and purpuric associated with melaena in the second patient. Eight of the 10 confirmed patients were working with sheep, and the disease ma y be a zoonotic viral infection.