XXXX control in Cul de Sac Valley, Saint Lucia. II. Chemotherapy as a supplement to a focal mollusciciding programme.

@entity1 @entity383 @entity14606 @entity380 @entity35128
After an intensive area-wide mollusciciding campaign, over four and a half years, transmission of @entity380 was reduced. A cheaper scheme suitable for the follow-up or consolidation stage of control was evaluated and two selective population chemotherapy campaigns using @entity35128 (2 mg/kg b.w.) and @entity14606 (15 mg/kg b.w.) were mounted. Prevalence dropped to 6% and 3% in areas with previously high and low levels of transmission respectively. Calculations suggested that these figures were falsely low and that perhaps 20% of the population were still excreting @entity383 ova in small numbers. The unco-operative groups in the population are probably more important in maintaining a reservoir of infection in the community than @entity1 with light infections undetected by the sedimentation concentration stool examination technique used. The benefit of more sensitive but more costly examination techniques is not clear since the importance of very light infections in transmission is uncertain. Case detection absorbs an increasing proportion of the total cost of chemotherapy programmes with fewer cases being found amongst the same number screened. Using @entity35128 (649 treated) the cost per @entity1 protected was  0.74 and using @entity14606 (264 treated)  0.94. The need to develop low cost consolidation or follow-up procedures for preventing a resurgence of transmission after successful control, when the infection is no longer of public health importance, is stressed.
