Chapter 10 : A Possible Dream: Control by Blocking Transmission

Abstract:

The oldest and most effective public health measures have been interventions that prevented or reduced the transmission of malaria. This chapter presents a discussion on the control of malaria by blocking its transmission. In August 1899, Ronald Ross identified the Anopheles mosquitoes that were the main transmitters and set about to eliminate their breeding sites. In 1947, an eradication campaign was sold to the nations of the world based on the near-miraculous blow that dichlorodiphenyltrichloroethane (DDT) had dealt to malaria. By 1950 many nations had antimalaria programs dependent on routine annual spraying with DDT. Another approach to blocking transmission involved reducing the infectivity of the human population itself to mosquitoes by widespread distribution and use of antimalarial drugs. An alternative to the use of antimalarial drugs to suppress human infectivity for mosquitoes is to develop and deploy vaccines designed to limit the transmission of human malaria infections to mosquitoes – transmission-blocking vaccine (TBV). One of the great potential strengths of proteins (Pfs48/45 and Pfs230) used for the malaria TBV is that these proteins are expressed in the human host so that there can be a boosting effect. Another vaccine, RTS,S, showed a 34% reduction in the first appearance of parasites in the blood over a 16-week period. Bed nets (mosquito nets) and sporozoite vaccines can also be effective transmission-blocking agents for malaria.