Table 2.
• | 100% MDA Coverage is very hard to achieve—and will only get more difficult as prevalence and intensities approach zero |
• | Praziquantel does not kill juvenile worms—which then grow up to be adults |
• | Production of enough praziquantel is a challenge—if we really treat everyone who is infected |
• | There may be a prevalence at which it is not longer cost-effective to keep doing MDA |
• | There may be a prevalence at which it is no longer acceptable to the population to undergo MDA |
• | Reinfection of treated people can continue to occur if infected snails remain in the environment |
• | The multiplicative phase of the life cycle is in the snail host (vector) |
• | If poor sanitation, vector snails and a few infected people remain—transmission will continue unless a “break point” in one of these parameters is achieved—but we do not know what that “break point” is. |