Nov 13 - 17, 2016


José L. Segura1, Eugenio Edu2, Giovanna Baltazar1, Luis Benavente1, Dianna Hergott1

1 Medical Care Development International, Silver Spring, MD, United States, 2 EG-Ministry of Health, Malabo, Equatorial Guinea

The 2012 WHO manual of surveillance for malaria control proposed the monitoring of suspected cases, however the same manual fostered the use of confirmed malaria cases. On other hand to ensure that lab results do not influence the condition of "suspected" in the registers, has been proven to be a challenge. Following WHO guidance, Bioko Island Malaria Control Project (BIMCP) has been reporting the number of suspected cases, composed by adding a) the number of outpatients lab tested for malaria plus b) the number of presumed malaria cases (clinical diagnosis or diagnosed without lab confirmation). After 11 years of BIMCP’s activity, Bioko is in transit from control phase to the pre-elimination, and a malaria surveillance system able to provide support for both phases is required. We have assessed the trends and composition of the group "suspected cases" to assess its contribution to the malaria surveillance. Between 2013 and 2016 the reduction in the average monthly number of suspected cases was quite slower (30%) compared with the decrease in its sub-group of confirmed malaria cases (75%), or the sub-groups with diagnostic behaviors potentially deviant of WHO guidelines (1. cases diagnosed as malaria without lab test, 2. cases diagnosed as malaria with negative test results, and 3. cases with a diagnosis other than malaria with a malaria test positive) which shown a decrease in the range of 68-71%. Conversely, among the suspected cases the average monthly number of cases with a malaria test negative and reported with a diagnosis other than malaria experienced an increase of 219%. We conclude that a) the number of suspected cases is not as sensitive as of confirmed cases to monitor the burden of disease, b) the training, supervision and availability of supplies for lab testing has allowed the reduction of undesirable diagnostic behavior, and c) clinicians may have in fact adopted more inclusive criteria to classify outpatients as malaria suspected cases along with the reduction of parasitemia in Bioko. NHIS data from at least the last four years will be analyzed to identify changes in the definition of suspected cases informally adopted by clinicians.