Infections due to Loa loa and Mansonella perstans are common yet elusive neglected filariases. Parasitological cure after treatment is very difficult to assess, as adult parasites are not accessible. Therefore, outside transmission areas, patients require a long follow-up period to ascertain the therapeutic outcome, which is impractical for non-sedentary populations such as migrants. We studied the change over time of microfilaremia, eosinophil counts, and antifilarial antibodies tested with a commercial ELISA test (Bordier Affinity Products, Crissier, Switzerland), in a retrospective cohort of patients with confirmed L. loa and M. perstans infections, to evaluate the role of serology in clinical practice. After treatment, all 22 eligible patients diagnosed in our center between 2015 and 2017 reached amicrofilaremia, with microfilarial counts decreasing sharply within 2 months. Paralleling eosinophil counts, antibodies decreased in all patients, 36% of whom reached sero-reversion or near-sero-reversion in < 20 months. These findings suggest that positive serology is not just residual from a past infection, and may be used for diagnosis even whenmicrofilaremia is negative or cannot be performed. Interestingly, antibodies andeosinophil counts increasedfollowing some, but not all, re-treatment courses. If the rise inthese parameters reflects death of macrofilariae, caution is required in interpreting high eosinophil counts and antibody titers shortly after treatment, as thesemay reflectnoneedfor further treatment.Tooptimizepatients'management, it isnowpivotal to ascertain the interval between treatment and macrofilarial death and therefore whether re-treatments are required for complete clearance of parasites.
ASJC Scopus subject areas
- Infectious Diseases