The first large-scale use of ddt occurred in italy in 1943 when the insecticide was used for dusting refugees in a successful attempt to prevent an outbreak of a deadly disease spread by body lice which frequently occurs under wartime conditions of overcrowding and poor sanitation. what disease did ddt prevent in this situation?

Answertyphus fever

answer: - b cells

explanation: -

there are many types of white blood cells present in our body. one such class of white blood cells are the lymphocytes. the b cells belong to the lymphocyte class of wbcs. the b cells perform their action against the pathogen by producing specialised proteins called as antibodies. these antibodies are produced as and when the b cells encounter pathogens in response to the antigens present on the surface of the pathogen. these antibodies bind to the antigens present on the pathogen and then, target them for destruction by other cells of the immune system.

so, the b cells mediate their action by identifying the antigens present on the surface of the pathogens and then producing antibodies in return to mediate its effect.