The Kenyan Health Ministry issued an alert Friday because of an outbreak of an unknown disease in western Kakamega County that has killed four people. The disease was discovered in the Mukumu Girls and Butere Boys high schools, with 627 patients ill as of April 14, Director General for Health Patrick Amoth said in a statement. “Unfortunately, we have lost 4 patients to this illness. We at the Ministry of Health send our heartfelt condolences to the families who have lost their loved ones,” said Amoth. The Health Ministry said the disease presents fever, abdominal pain or cramps, vomiting and diarrhea. Comprehensive investigations are currently underway to determine the cause. Data analyzed indicates that the disease seems to have started March 15. The government has since closed the two affected schools as investigations continue. Meanwhile, 19 students suffering from the illness are in stable conditions at seven health facilities across the country. The Ministry has taken several water, food and human tissue samples from affected areas for preliminary laboratory investigations. The tests conducted have revealed similar symptoms to those seen in enterotoxigenic E. coli and salmonella typhi patients. Laboratory tests for viral hemorrhagic fevers, including Ebola, Marburg, Leptospirosis and Crimean-Congo hemorrhagic fever, dengue fever, Rift Valley Fever and the West Nile virus have been negative. The outbreak has sparked concern with many Kenyans worried about its spread to other parts of the country.