The first part of the course reviews the diversity of micro-organisms including Viruses Bacteria, Fungi and Protozoa.  Their importance in nature and effects on man will be emphasized.  The course discusses the uses of microbes – both beneficial and adverse.  The second part of the course examines heterospecific associations with special emphasis on parasitism.  The life cycles and control measures against some common parasites will be discussed e.g. Plasmodium, Trypanosoma, Schistosoma, Fasciola, Ascaris, Onchocerca and Dracunculus.