Mansonella ozzardicorneal lesions in the Amazon: a cross-sectional study

Abstract

ObjectivesTo characterise and confirm the presence of Mansonella ozzardi microfilariae in the cornea by biomicroscopy and corneal confocal microscopy.DesignCross-sectional study.SettingsClinical practice study in patients from rural communities in Coari city on the Solimões river, Amazonas state, Brazil.ParticipantsThe eyes of 212 consecutive volunteer patients were examined using a flash light and their blood checked for the presence of microfilariae by an expert microscopist. Patients with suspicious corneal lesions (characterised as nummular keratitis) were submitted to biomicroscopy, fundoscopy and corneal confocal microscopy evaluation (CCME). In two patients, a biopsy of the limbal conjunctiva adjacent to the nummular keratitis was carried out and blood collected from the surgical wound for microfilariae investigation by thick blood film examination.Primary and secondary outcome measuresPositive correlation between corneal biomicroscopic and confocal lesions and M ozzardi microfilaremia.ResultsOf the 212 patients, 56 (26.4%) were positive for microfilaremia. 22 patients with nummular keratitis identified under flash light examination underwent biomicroscopy and CCME. Corneal lesions were positively correlated to microfilaremia (p=0.0001). At biomicroscopy, lesions were classified as quiescent or active. At CCME, lesions were categorised as circular or filiform. The associations between corneal lesions, CCME findings and microfilaremia are shown.ConclusionsWe describe M ozzardi microfilariae in the cornea and the associated eye pathology. Further studies using ocular tissue PCR and other imaging techniques would be helpful.

Mansonella ozzardi: a neglected New World filarial nematode

“…76 Finally, another cross-sectional survey in Coari found corneal lesions in 14 of 56 (25%) microfilaremic subjects and 8 of 156 (5%) uninfected controls. 77 These authors also provided the first report of M. ozzardi microfilariae identified in the cornea. They found, by confocal microscopy, linear lesions consistent with M. ozzardi microfilariae in the cornea of seven subjects; two of them had microfilariae detected on Giemsa-stained smears prepared with blood from the limbal conjuntiva.…”

“…They found, by confocal microscopy, linear lesions consistent with M. ozzardi microfilariae in the cornea of seven subjects; two of them had microfilariae detected on Giemsa-stained smears prepared with blood from the limbal conjuntiva. 77 Although there is no definitive evidence that migrating M. ozzardi microfilariae can directly cause corneal lesions, a careful eye examination is recommended to be part of the routine clinical care of infected subjects, regardless of any symptoms. In areas of Central and South America where M. ozzardi and O. volvulus co-occur, skin biopsies are mandatory to rule out onchocerciasis as a cause of corneal lesions.…”

Sustained Clearance of Mansonella ozzardi Infection after Treatment with Ivermectin in the Brazilian Amazon

“…8,12,13 Currently, researchers are trying to correlate the occurrence of ocular lesions on the cornea with mansonelliasis. [14][15][16] However, Bartoloni and others 17 described infections as asymptomatic.…”

Mansonelosis por Mansonella ozzardi en voluntarios para despistaje de malaria en la Amazonía peruana

“…Esta frecuencia hallada concuerda con la reportada por Jones et al (18) en la misma localidad; probablemente en las comunidades más rurales y alejadas de Santa María la frecuencia sea mayor. Otras limitaciones fueron la falta de estudio de las tumoraciones subcutáneas y de otros exámenes oftalmológicos y de laboratorio especializados, que hubieran permitido proporcionar más evidencia de la relación entre la infección y las lesiones encontradas; por ejemplo, establecer si el reporte de disminución de la agudeza visual de los pacientes se relaciona con lesiones corneales que se han encontrado en pacientes infectados con M. ozzardi en otro estudio (26) .…”