Wolbachia bacteria in Mansonella perstans isolates from patients infected in different geographical areas: a pilot study from the ESCMID Study Group for Clinical Parasitology

Background: Mansonella perstans is a vector-borne filarial parasite widely endemic in sub-Saharan Africa, with sporadic cases in Latin America. Infection is often overlooked; treatment is not standardized, and effectiveness of common regimes is difficult to ascertain. Anti-Wolbachia macrofilaricidal treatment with doxycycline has been applied, but there are scant and contrasting reports about the presence of Wolbachia in M. perstans isolates from different geographical locations. Taking advantage of a network of European centres expert in traveller and migrant health, we aimed to expand the knowledge concerning the distribution of Wolbachia in M. perstans to contribute to the design of optimal treatment approaches. Methods: We analysed 19 samples of concentrated microfilariae or whole blood from M. perstans-infected patients who reported having resided or travelled in one or more of 10 West African countries. Wolbachia was detected by PCR targeting 16S and ftsZ genes and phylogenetic analysis of M. perstans was performed based on COX1 gene sequencing. Results: Wolbachia was identified in 14/19 (74%) samples. With the possible inaccuracy deriving from potential origin of infection being identified retrospectively from routine clinical visit’s documents, this study identified Wolbachia in M. perstans from Burkina Faso, Equatorial Guinea, Republic of Guinea and Senegal for the first time to our knowledge. Furthermore, Wolbachia might also be present in M. perstans from Democratic Republic of the Congo, Mali, Niger and Nigeria. Conclusions: The retrieval of Wolbachia-positive and Wolbachia-negative M. perstans samples can either be explained by technical limitations or reflect the real existence of Wolbachia-positive and Wolbachia-negative M. perstans populations. However, this latter hypothesis was not supported by our phylogenetic analysis. Our results suggest that doxycycline could be used for the treatment of M. perstans infection upfront or, if possible, after ascertaining the presence of Wolbachia by PCR performed on concentrated microfilariae using two targets to avoid false-negative results.