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

Parasites & Vectors volume 18, Article number: 97 (2025) Cite this article

Abstract

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.

Graphical Abstract

Background

Mansonella perstans is a vector-borne filarial parasite endemic in sub-Saharan Africa, with cases also occurring in the Caribbean and Central and South America [1, 2]. It is estimated that 100 million people are infected, with prevalences up to 70–100% reported in areas of Cameroon, Ghana and Uganda [1–5]. Mansonella perstans is also diagnosed in migrants from sub-Saharan Africa to Europe [6], with prevalences reported between 4–11% [7–10]. However, these figures are probably underestimated since infection is often overlooked because of its inconstant positivity on serology screening for filariasis and unspecific clinical presentation [6, 11–14]. Despite being considered low pathogenic, the real health impact of mansonellosis is not well defined. Treatment of M. perstans is not standardized and in some cases not even applied [6, 15]. Even outside endemic areas, where re-infection cannot occur, refinement of treatment schedules and assessment of macrofilaricidal activity is extremely difficult. Parasitological cure can only be indirectly evaluated by monitoring microfilaraemia or serology over months to years [16] due to the inaccessibility of adult worms living in connective tissues and serosal cavities. However, the long follow-up required to assess cure is not easily implementable in mobile populations such as migrants, and positivity at a too early follow-up might not reflect treatment failure and lead to unnecessary repeated treatments.

Prolonged courses of mebendazole, alone or in combination with diethylcarbamazine, seem the most effective treatment strategies, but their effectiveness in reaching parasitological cure is uncertain [15, 16]. Treatment with doxycycline for 4–6 weeks targeting Wolbachia has reliably proven macrofilaricidal on filariae harbouring Wolbachia endosymbionts such as Wuchereria bancrofti and Onchocerca volvulus [17]. However, there are still contrasting reports and overall scant data about the presence of Wolbachia in M. perstans isolates from different geographical locations and, therefore, the applicability upfront of doxycycline for the treatment of this infection. Early investigations from Uganda and Gabon did not find evidence of Wolbachia in M. perstans microfilariae using PCR [18, 19]. However, later studies performed in Gabon and Cameroon [20, 21] and clinical trials with doxycycline in Mali [22, 23] and Ghana [24], showed that Wolbachia was present in M. perstans and that treatment was effective in significantly reducing microfilaraemia, probably reflecting an adulticidal effect. In these studies, 40–50% [20, 23] to 75–100% [22, 24] of blood samples with M. perstans microfilariae were Wolbachia-positive. Notably, PCR for Wolbachia is not standardized; therefore, different results could also derive from the application of different pre-analytical and analytical procedures even when the same targets are used (e.g. 16S rDNA and ftsZ that are the most common targets used for Wolbachia PCR [18, 20, 23, 24]). Interestingly, Sinha et al., [21] recently showed that two different M. perstans isolates from Cameroon had different loads of Wolbachia bacteria per microfilaria, suggesting that Wolbachia levels can vary widely between parasite populations. To complicate the picture further, a new Mansonella species, Mansonella sp. “DEUX”, morphologically indistinguishable from M. perstans, was identified in Gabon [25–27]. Wolbachia was detected by PCR in 33% Mansonella sp. “DEUX” mono-infections isolates [26].

Taken together, available data suggest that Wolbachia is present in M. perstans. However, the co-existence of Wolbachia-free and Wolbachia-positive populations cannot be excluded. In this project, taking advantage of a network of European centres specialized in traveller and migrant health, we aim to expand the knowledge concerning the distribution of Wolbachia in M. perstans populations to contribute to the design of optimal treatment approaches to this neglected filarial disease.

Methods

Study design and objectives

In this cross-sectional study, we analysed isolated M. perstans microfilariae and M. perstans-positive samples, collected from infected patients during routine diagnostic procedures for filariasis, irrespective of whether the diagnosis was based on investigations of suggestive signs/symptoms (e.g. eosinophilia) or in the context of a geographically oriented screening (e.g. positivity on screening with filarial serology) already available or prospectively collected between April 2021-March 2024. The objectives were to evaluate the presence of Wolbachia in M. perstans microfilariae obtained from patients and the distribution of Wolbachia-positive and Wolbachia-negative M. perstans populations according to the geographical origin of the infection.

Study population and data collection

Samples were obtained from patients diagnosed with M. perstans infection who consented to their storage and use for research purposes. Inclusion criteria were: (i) M. perstans infection was diagnosed by molecular analysis or identification of microfilariae using microscopy; (ii) the sample was collected before treatment with doxycycline (for retrospective samples, treatment information was derived from the medical records); (iii) the sample was processed and stored according to study requirements (see sample processing eligibility criteria in the “Molecular analysis” paragraph below); (iv) the patient’s country of birth and/or the possible country/countries of infection was available. Samples from patients with M. perstans infection which did not meet inclusion criteria were excluded from the study.

Other data retrieved from medical records, if available, were: patient’s sex, age, quantity of blood processed for the original diagnosis, diagnostic method (microscopy after sedimentation/filtration, molecular analysis), number of microfilariae per ml blood and co-infection with other filarial species.

Molecular analyses

Sample processing eligibility criteria were: (i) microfilariae were retained on filters after blood filtration or obtained from leukoconcentration/sedimentation techniques routinely implemented in each centre without application of formalin or acetic acid, stored at − 80 °C or in ethanol; (ii) whole blood stored at − 80 °C; (iii) DNA extracted from whole blood or concentrated microfilariae, stored at − 80 °C. No specific requirements were applied to type of collection tube or length of sample storage.

DNA was extracted from concentrated microfilariae or 500 µl whole blood using a QIAmp Blood and Tissue DNA extraction kit (Qiagen, Hilden, Germany) following the manufacturer’s instructions. Briefly, frozen samples were thawed, mixed with lysis buffer and proteinase K, mechanically disrupted with ceramic bead-beating (MagNA Lyser, Roche, Basel, Switzerland) and incubated at 56 °C overnight. DNA was purified on columns and eluted in 50 µl AE buffer.

PCR reactions were performed using primers and TaqMan probes targeting filarial ITS1 and Wolbachia ftsZ and 16S (Supplementary Table S1). A pre-amplification was performed with endpoint PCR for the ITS1 gene (20 cycles) and Wolbachia ftsZ and 16S genes (30 cycles). The reaction mixture was composed of HotStarTaq Master Mix (Qiagen) and primers at 400 nM final concentration in a final volume of 25 µl. Mansonella perstans, Mansonella sp. “DEUX” and Wolbachia-specific real-time PCR reactions (45 cycles amplification) were performed. Wolbachia-negative Loa loa [19] was confirmed using specific real-time PCR (ITS1) after pre-amplification for samples with co-infection by microscopy. Real-time PCR mix was composed of SsoAdvanced Universal Probes Supermix (BioRad, Hercules, CA, USA) with primers at 400 nM and probes at 200 nM final concentrations in a final volume of 25 µl. To exclude the possibility that Wolbachia positivity was derived from submicroscopic infections with W. bancrofti, the presence of this parasite was investigated using the oligonucleotides reported in [28]; pre-amplification and real-time PCRs were performed as described above.

A first set-up of the molecular analyses was carried out using DNA extracted from control samples positive for M. perstans, L. loa and W. bancrofti. Subsequently, analyses on the study samples were performed using synthetic amplicons as positive control and water as negative (no template) control.

Sequencing and phylogenetic analysis

All study samples (Table 1) were analysed using Sanger sequencing for the COX1 region (464 bp) using primers reported in Supplementary Table S1. PCRs were performed using HotStarTaq Master Mix (Qiagen) at 60 °C for the annealing. PCR products were purified by enzymatic method (ExoSAP-IT™ PCR Product Cleanup Reagent, Thermo Fisher Scientific, Waltham, MA, USA) followed by cycle sequencing with BigDye™ Terminator v3.1 kit (Thermo Fisher Scientific). Sequences were analysed with the ABI3500 instrument (Applied Biosystems, Thermo Fisher Scientific). Data were analysed together with COX1 genes available in NCBI Nucleotide (search query: “cox1 AND ("Mansonella perstans"[ORGN])”, acc. date: 18/10/2024), selecting only from humans. A multiple sequences alignment (MSA) was done using MAFFT v. 7.520 (2023/Mar/22) with option –maxiterate 1000. The resulting MSA was used for the phylogenetic analysis with IQ-TREE v. 2.3.5 (options: -keep-ident, -model-joint UNREST, –root-test, -B 1000, -T auto). TreeViewer v. 2.2.0 was used to visualize the tree.

Table 1 Origin/potential origin of Wolbachia-positive and Wolbachia-negative samples
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Statistical analysis

Samples were considered Wolbachia-positive if at least one gene (Wolbachia ftsZ and/or 16S) was amplified. Data are described as counts and percentages. Microfilarial load (mf/ml blood) in the original sample and starting quantity of blood analysed for the diagnosis were graphically compared between Wolbachia-positive and Wolbachia-negative groups.

Results

Patients’ origin and other possible countries of infection

Nineteen samples were available for the analysis: 15/19 (79%) were concentrated microfilariae from 10 ml (n = 7) or 1 ml (n = 8) blood, 3/19 (16%) were frozen whole blood samples from which the original diagnosis was made by PCR, and 1/19 (5%) samples were extracted DNA from 200 µl blood originating from a sample on which the diagnosis was made by microscopy. In 14/19 (74%) cases, patients were males; the median age was 26 (range 17–69) years. Figure 1 shows patients’ country of birth (orange) and reported possible countries of infection (yellow) if more than one endemic country was visited by the patient (n = 9 African patients) or if the country of birth was not endemic for M. perstans (n = 1 from Belgium and n = 1 from Spain). In two cases, L. loa co-infection was diagnosed by microscopy of concentrated blood. Detailed per-patient information is available at https://zenodo.org/records/14197836.

Fig. 1
figure 1

Mansonella perstans-endemic country of birth (orange) or other possible country of infection (yellow) of patients from whom samples were analysed. DRC Democratic Republic of the Congo. Map produced using www.yourfreetemplates.com

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Filariae identification and Wolbachia detection

Mansonella perstans, Mansonella sp. “DEUX” and L. loa identifications were confirmed by real-time PCRs for filarial ITS1 on reference control DNA samples. The Wolbachia 16S gene was amplified only in M. perstans whilst ftsZ was amplified in M. perstans and Mansonella sp. “DEUX”.

Analysing the study samples, M. perstans infection was confirmed in all 19 samples; no Mansonella sp. “DEUX” was identified. Loa loa co-infections on microscopy were also confirmed by molecular analysis; no submicroscopic infection with W. bancrofti was detected.

Wolbachia was identified in 14/19 (74%) samples (Table 1). Amplification of both 16S and ftsZ genes was obtained in 7/14 (50%) specimens, while the remaining were positive only for 16S (5/14; 36% samples) or ftsZ (2/14; 14% samples). The origin or potential origin of Wolbachia-positive and Wolbachia-negative samples is detailed in Table 1 and Fig. 2.

Fig. 2
figure 2

Origin or potential origin of Wolbachia-positive and Wolbachia-negative samples. Dark green: only Wolbachia-positive isolates and no reported alternative origin. Light green: only Wolbachia-positive isolates with reported alternative origin of Wolbachia-positive isolates. Grey: only Wolbachia-negative isolates with reported alternative origin of Wolbachia-negative isolates. Green-grey striped: both Wolbachia-positive ad Wolbachia-negative isolates with no reported alternative origin. Blue-grey striped: both Wolbachia-positive and Wolbachia-negative isolates with reported alternative origins of both positive and negative samples. DRC Democratic Republic of the Congo. Map produced using www.yourfreetemplates.com

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No evident difference between Wolbachia-positive and Wolbachia-negative samples could be observed in terms of original microfilarial burden, while the starting quantity of blood could have been relevant (Fig. 3). Statistical analysis was not performed because of the small number of samples and lack of standardization of original diagnostic procedures and thus the quantity of material available for this study.

Fig. 3
figure 3

Relation between characteristics of blood samples originally used for diagnosis and positivity or negativity of Wolbachia PCR. A Original microfilarial burden (mf/ml) in Wolbachia-positive and Wolbachia-negative samples (data available for n = 16/19 samples). The horizontal line indicates median value. B Percentage of Wolbachia-positive and Wolbachia-negative samples originating from DNA extracted from concentrated microfilariae from 10 ml blood (black), from concentrated mf from 1 ml blood (dark grey) and from 200 µl (light grey) or 500 µl (white) whole blood

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Phylogenetic analysis

To evaluate whether presence or absence of Wolbachia could relate to the presence of different M. perstans populations, we performed a phylogenetic analysis by MSA of the mitochondrial COX1 gene sequences obtained in this study and available in NCBI. Sixteen of 19 (84%) samples could be sequenced. M. perstans grouped into two branches; however, Wolbachia-positive and Wolbachia-negative samples could be found in both (Fig. 4), suggesting no separate evolution of Wolbachia-positive and Wolbachia-negative M. perstans populations.

Fig. 4
figure 4

Phylogenetic analysis of M. perstans samples based on the mitochondrial gene COX1. The figure shows the phylogenetic analysis performed with IQ-TREE v.2.3.5 using the UNREST model with bootstrap replicates of 1000 on our 16 samples and the sequence available in NCBI database. The numbers on nodes indicate the percentage of identity with the reference genome M. perstans NC_077638.1. The colors on tips represent the Wolbachia status (red = Wolbachia negative, green = Wolbachia positive, grey = no information on Wolbachia)

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Discussion

In this study, we aimed to expand the knowledge about the presence of Wolbachia bacteria in M. perstans isolates from different geographical origins.

We confirmed the presence of Wolbachia in 14/19 (74%) M. perstans samples, suggesting that Wolbachia is consistently present in M. perstans and, for a practical clinical approach, doxycycline can be used to treat M. perstans infection as a first line provided that monitoring of cure is possible or after ascertaining the presence of Wolbachia by PCR performed on concentrated microfilariae from 10 ml blood and using two PCR targets to minimize false-negative results. No Mansonella sp. “DEUX” isolates were identified in our sample cohort; the distribution of this new species beyond Gabon therefore remains to be elucidated.

Wolbachia-positive M. perstans samples were obtained from patients born in Burkina Faso, Cameroon, Equatorial Guinea, Republic of Guinea, Guinea Bissau and Senegal and born in Europe but reportedly having been infected in Cameroon or DRC. Four of the African patients reported one or more possible countries of infection in addition to the country of birth, including Mali, Niger and Nigeria. Although with possible inaccuracy deriving from countries of potential infection being identified retrospectively from travel history collected during the routine clinical visit, this study identified Wolbachia in M. perstans solely attributed to infection in Burkina Faso, Equatorial Guinea, Republic of Guinea and Senegal and confirmed the presence of Wolbachia in isolates from Cameroon for the first time to our knowledge. Furthermore, Wolbachia might also be present in M. perstans from DRC, Mali, Niger and Nigeria. Wolbachia was not identified in 5/19 (26%) isolates. Equatorial Guinea and Senegal were the only reported countries of infection of two patients; the other three patients came from Senegal or Benin and reported having travelled in Burkina Faso, Mali or Niger.

The identification of both Wolbachia-positive and Wolbachia-negative M. perstans samples could be explained by technical limitations of the DNA amplification or reflect the real existence of M. perstans populations containing and free of the bacteria. When focusing on the first hypothesis, the results could originate from (i) differences in the type and quantity of sample analysed, influencing the eventual number of microfilariae in the volume used for DNA extraction, and (ii) the recently reported variability in Wolbachia levels among M. perstans populations [21]. As for the second hypothesis, the presence of Wolbachia-positive and Wolbachia-negative isolates from the same country and the findings of the phylogenetic analysis support its rejection and point in favour of the result being a technical issue rather than a real biological feature, but this could not be formally excluded because of the uncertain origin of the infections. Prospective studies applying the same pre-analytical procedures, or randomized clinical trials with doxycycline, would be more appropriate to address this hypothesis. In the absence of an animal model for M. perstans mansonellosis, clinical trials with doxycycline are also needed to address the symbiotic role of Wolbachia and its requirement for survival in M. perstans. Indeed, such a symbiotic role is suggested by the response to treatment in clinical trials [22–24] and has been conclusively ascertained for other filarial species [17] but still remains to be formally confirmed in M. perstans. However, such prospective studies are extremely difficult to perform in clinical centres attended by migrants because of the different locally available routine diagnostic procedures and capacities, the long time required to reach an adequate sample size prospectively and the difficulty in performing an adequate follow-up in this highly mobile population. Further studies in different endemic countries could overcome the sampling issue and mitigate the uncertainty deriving from possible multiple origins of infection in migrants. The recently described in vitro culture system for M. perstans L3 from Culicoides vectors [29] could also offer an interesting alternative to using microfilariae (thus, overcoming the problems deriving fromlow/variable Wolbachia loads per microfilaria and possible coinfection with Wolbachia-positive and Wolbachia-negative M. perstans parasites), allowing the analysis of pre-adult M. perstans stages while also avoiding human sampling.

This study has several limitations, the first being the limited number of samples available. This was due to the unspecific clinical presentation of mansonellosis, which makes its diagnosis possible de facto only in the context of screening of patients from endemic areas, or in case of strong clinical suspicion, and the uneven influx of patients in clinical centres. Furthermore, storage of samples for future studies cannot be routinely implemented in many hospitals, limiting the availability of suitable stored samples. Second, much information such as the countries where the patients resided or travelled and previous treatments received, was retrieved from visit reports and could have been inaccurate or incomplete. Furthermore, no data on length of stay (or other travel information) in each country of possible infection were reliably available. However, while missing data on the countries visited could impact the results of our study, we believe it is improbable that long-term treatment with doxycycline (or any other antibiotics that target Wolbachia) right before diagnosis could have been missed and therefore influenced the results of the study. Third, samples originated only from West-Central Africa. Therefore, the distribution of Wolbachia in M. perstans from other endemic areas could not be examined. Furthermore, the pre-analytical procedures of samples were not standardized. Finally, we could not formally exclude infection with the Wolbachia-containing O. volvulus in patients from which samples were derived, nor did we perform O. volvulus-specific PCR on the subset of whole blood samples available (the negative results of which, in any case, would not have excluded infection with certainty since O. volvulus microfilariae do not circulate in blood). However, we believe that this probably would not have confounded the results of our study since (i) any Onchocerca-suspected nodule in a patient attending a centre involved in the study would have been palpated, reported in the clinical records and further investigated; (ii) the diagnosis of onchocercosis in migrants to Europe is exceedingly rare [30]; (iii) only a few patients with ochocerciasis have detectable levels of Wolbachia in their blood before microfilaricidal treatment, which causes massive release of Wolbachia and clinical side effects [31, 32].

Conclusions

Taken together, our results support the hypothesis that Wolbachia is present in M. perstans from West Africa. Our results also support the clinical management of patients with M. perstans infection with doxycycline if follow-up is possible. An alternative approach, especially for patients from East Africa and Latin America, where the presence of Wolbachia in M. perstans is unexplored, could be deciding on treatment on a case basis based on results of PCR for Wolbachia.

Availability of data and materials

The raw data file is available at https://zenodo.org/records/14197836. Amplicon sequences were submitted to GenBank, accession numbers PQ525011-PQ525012, PQ525001-PQ525010, PQ525247, PQ524992-PQ524995.

Abbreviations

DRC:

Democratic Republic of the Congo

ESCMID:

European Society of Clinical Microbiology and Infectious Diseases

MSA:

Multiple sequences alignment

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Acknowledgements

We thank Joseph Turner at Liverpool School of Tropical Medicine for the suggestions provided about Wolbachia identification during the planning of the study. We also acknowledge Sandra Alvarado at Hospital La Paz-Carlos III, Madrid, Spain, and Eleonora Rizzi and Salvatore Scarso at IRCCS Sacro Cuore Don Calabria Hospital, Negrar, Italy, for help with sample collection and/or processing in these institutes. We thank Tropica Biobank (bbmri-eric:ID:IT_1605519998080235) for providing clinical samples for the Negrar centre. 

Funding

This study was funded by Research Grant 2021 from the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) to EP and by the Italian Ministry of Health, Fondi “Ricerca Corrente”-L2 to IRCCS Sacro Cuore Don Calabria Hospital, Negrar. DV was funded by the Division of Intramural Research (DIR) of NIAID/NIH USA. The funding sources had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

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Authors and Affiliations

  1. Department of Infectious-Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, 37024 Negrar Di Valpolicella, Verona, Italy

    Elena Pomari, Denise Lavezzari, Monica Degani, Stefano Tais, Federico Gobbi & Francesca Tamarozzi

  2. Systems Genomic Section, Laboratory of Parasitic Diseases, Division of Intramural Research, NIAID, NIH, Bethesda, MD, 20894, USA

    Denis Voronin

  3. Microbiology Department, Hospital Clinic, 08036, Barcelona, Spain

    Miriam J. Alvarez-Martinez

  4. ISGlobal, University of Barcelona, 08036, Barcelona, Spain

    Miriam J. Alvarez-Martinez

  5. National Referral Unit for Imported Tropical Diseases and Health Travel, Hospital La Paz-Carlos III, 28034, Madrid, Spain

    Marta Arsuaga

  6. Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28029, Madrid, Spain

    Marta Arsuaga, María Pilar Luzón-García, Joaquín Salas-Coronas, Fernando Salvador & Elena Sulleiro

  7. Department of Clinical Sciences, Institute of Tropical Medicine, 2000, Antwerp, Belgium

    Emmanuel Bottieau & Marjan Van Esbroeck

  8. Tropical Medicine Unit, Hospital Universitario Poniente, El Ejido, 04700, Almería, Spain

    María Pilar Luzón-García, Joaquín Salas-Coronas & Manuel Jesús Soriano-Pérez

  9. Swiss Tropical and Public Health Institute, 4123, Allschwil, Switzerland

    Beatrice Nickel

  10. University of Basel, 4001, Basel, Switzerland

    Beatrice Nickel

  11. Malaria & Emerging Parasitic Diseases Laboratory, National Centre of Microbiology, Instituto de Salud Carlos III, 28221, Madrid, Spain

    Jose Miguel Rubio

  12. Department of Nursing, Physiotherapy and Medicine. Faculty of Health Sciences, University of Almeria, 04120, Almeria, Spain

    Joaquín Salas-Coronas

  13. International Health Unit Vall d’Hebron-Drassanes, Infectious Diseases Department, Vall d’Hebron University Hospital, PROSICS Barcelona, 08035, Barcelona, Spain

    Fernando Salvador

  14. Microbiology Department, Vall d’Hebron University Hospital, PROSICS Barcelona, 08035, Barcelona, Spain

    Elena Sulleiro & Lidia Goterris

  15. Department of Medical Microbiology and Infectious Diseases, Erasmus MC University Medical Center, 3015, Rotterdam, The Netherlands

    Jaap J. van Hellemond

  16. Leiden University Center for Infectious Diseases (LUCID), Leiden University Medical Center, 2333 ZA, Leiden, Netherlands

    Linda J. Wammes

  17. Struttura Organizzativa Dipartimentale Malattie Infettive e Tropicali, Azienda Ospedaliero-Universitaria Careggi, 50134, Florence, Italy

    Lorenzo Zammarchi

  18. Dipartimento di Medicina Sperimentale e Clinica, Università degli Studi di Firenze, 50134, Florence, Italy

    Lorenzo Zammarchi

  19. Institute of Tropical Medicine, Eberhard Karls University Tuebingen, 72074, Tuebingen, Germany

    Jana Held

  20. German Center for Infection Research, Partner Site Tübingen, 72074, Tübingen, Germany

    Jana Held

  21. Centre de Recherches Médicales de Lambaréné, 242, Lambaréné, Gabon

    Jana Held

  22. Department of Clinical and Experimental Sciences, University of Brescia, 25121, Brescia, Italy

    Federico Gobbi

Authors
  1. Elena Pomari
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  2. Denis Voronin
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  23. Francesca Tamarozzi
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Contributions

Study conception and design: EP, FT, FG. Data collection: EP, DV, MJAM, MA, EB, MPLG, BN, JMR, JSC, FS, MJSP, ES, LG, MVE, JJvH, LJW, LZ, DL, MD, ST, JH, FG. Data curation: EP, FT. Data analysis: EP, DV, DL, FT. Interpretation of results: EP, DV, DL, FT. Figures generation: FT, DL. Draft manuscript preparation: EP, FT. All authors revised the manuscript critically for scientific content and approved the final version of the manuscript.

Corresponding author

Correspondence to Francesca Tamarozzi.

Ethics declarations

Ethics approval and consent to participate

The study was registered in ClinicalTrials.gov; registration code: NCT06311344. Ethical approval was granted by the ethics committee of IRCCS Sacro Cuore Don Calabria Hospital (Negrar, Verona, Italy; Ethics Committee of Verona and Rovigo provinces Prot n.21711 of 12/04/2021) and of participating centres (Supplementary Text S1). All samples were from patients who consented in writing to the to the storage and use for research purposes of their biological samples.

Competing interests

The authors declare no competing interests.

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Pomari, E., Voronin, D., Alvarez-Martinez, M.J. et al. Wolbachia bacteria in Mansonella perstans isolates from patients infected in different geographical areas: a pilot study from the ESCMID Study Group for Clinical Parasitology. Parasites Vectors 18, 97 (2025). https://doiorg.publicaciones.saludcastillayleon.es/10.1186/s13071-025-06723-0

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Keywords

Parasites & Vectors

ISSN: 1756-3305

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