Dear Corey,
You are correct that the questions about "fever in the last two weeks" is only found in the KR dataset and parasitemia data located in the PR dataset. It is important to note that questions on fever are asked about children 0-59 months of age of interviewed women for a period of two weeks before the survey whereas malaria parasitemia testing is done on all eligible, consented children 6-59 months of age in the household whether or not his/her mother is interviewed. Thus if you are linking fever and parasitemia your analyses is limited to children born to interviewed mothers who had valid test results for microscopy or RDT (depending on which measure you are using).

That being said it is possible to link fever and parasitemia by merging the PR and KR files for Benin. You can read more about merging datasets on our website.
http://dhsprogram.com/data/Merging-Datasets.cfm

To merge the PR and KR files you will need to rename the unique identifiers in the PR file for cluster, household and line number to match the KR file. Please keep in mind that there will be children that do not properly merge because this merge will produce unmatched observations (children who were tested for malaria but their mothers were not interviewed as part of the women's questionnaire so we do not have information about recent fevers in the PR but not the KR as well as children of interviewed mothers for whom we do not have parasitemia data in the KR but not the PR).

Let us know if you have any additional questions