What tropical diseases can be spread by close contact like kissing?

Not many. Chancroid is a bacteria which may be spread by sexual contact. It is seen in parts of asia and africa. The lepromatous form of leprosy is thought to be spread by water droplets from the nose or mouth so it is possible. Unfortunately most tropical diseases are spread by pararsites, mosquitos, etc.
Not many. Fortunately most tropical diseases are not spread by close sexual contact. The one I can think of is chancroid which is found in parts of asia and africa. The lepromatous form of leprosy may be passed by water drops from the mouth and nose. However most people are not infected by close contact with lepors unfortunately most are passed on by parasites like mosquitos or in water.