Complex sentence: Three months passed with no new reports of cases, but on 29 June Liberia reported that the body of a 17-year-old boy who had been treated for malaria tested positive for Ebola.
Split into simpler sentences: Three months passed with no new reports of cases. However on 29 June Liberia reported that the body of a 17-year-old youth, who had been treated for malaria, tested positive for Ebola.