What are the main communicable diseases found in the large hydro power dam during its construction and operation periods?
I am not sure why you are asking this question and whether you are more interested in the effects of dams or in communicable diseases. At any rate, many scientists are currently interested in how things we are doing to our environment may be affecting the frequency and spread of various diseases. One famous example of the effect of a dam on human health is the story of the Aswan Dam. Built on the Nile to control flooding and generate electricity, the dam caused permanent flooding of some areas. This allowed a population explosion of snails - snails carrying a parasititc flatworm that infected the fisherman who waded in the water. BTW - You might want to explore the websites of the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) to learn more about the infectious diseases that are threats to human health in the US and in the rest of the world. A report by the WHO on Human Health and Dams, published in 1999, is also available online.