 The British troops soon began to suffer from malaria; within a month of seizing the island, they had over 8,000 fever cases.The medical provisions for the expedition proved inadequate despite reports that an occupying French force had lost 80% of its numbers a few years earlier, also due to disease.Once it had been decided to garrison Walcheren Island in September 1809, Pitt was replaced by Lieutenant-general Eyre Coote who in October was replaced by Lieutenant-general George Don.