The Parasitological Surveillance in the country includes screening of individuals attending medical institutions and village level screening done in malarious localities. Screening done at medical institutions is categorized as Passive Case Detection (PCD) which included medical institutions where is no Public Health Laboratory Technician (PHLT) or Public Health Field Officer (PHFO) or Activated Passive Case Detection (APCD) which includes medical institution where there is either a PHLT
and/or a PHFO. Village level screening is done by Active Case Detection (ACD) and Mobile Malaria Clinics. Microscopy is the main diagnostic method while Rapid Diagnostic tests (RDTs) are also being used as a supplementary tool.
Activated Passive Case Detection (APCD) is the most important method of detection of malaria cases, accounting for about 97% of the cases detected. The Anti Malaria Campaign recommends screening all fever patients having symptoms and signs suggestive of malaria attending activated medical institutions (APCD centres)
for malaria. At present approximately 325 medical institutions, located predominantly in the dry and intermediate zones of the country have been activated through the appointment of a PHLT and/or a PHFO
. Even though this is roughly about 26% of all the medical institutions in the country, almost all the important medical institutions in the previously malaria endemic areas activated.
Active Case Detection (ACD) and Mobile malaria clinics are carried out in high risk localities at village level through focal screening of populations by home visits. These methods are mainly used to facilitate early detection of malaria cases (including asymptomatic parasite carriers) thereby reducing the possibility of transmission. About 30% of the total blood smears screened in the country are collected through these two methods.
Screening potential blood donors and donor blood for malaria is another important function done by the PHLTT attached to AMC. Categorized under passive case detection (PCD), this accounts for approximately 20% of total blood films screened. Screening of all donor blood for malaria before transfusion is mandatory in Sri Lanka at present.