Epidemiological Analysis of the 2019 Dracunculiasis Outbreak in the Liwi Area, Salamat Province (Chad): Evidence of the Role of Pets

Aims: Dracunculiasis is a neglected disease caused by a parasitic nematode, Dracunculus medinensis, also called the filaria of Medina. An outbreak of this disease occurred in the Salamat province in Chad in 2019, while the eradication of this disease worldwide was in its final stage. The outbreak occurred in the Bogam village (Liwi area), where this disease has never been reported in the past. The present work is aimed at identifying the factors that would have favored that outbreak, and the constraints that delay the eradication of dracunculiasis in Chad.

Study Design: Retrospective study.

Place and Duration of Study: The data retrospectively analyzed are those recorded during the census of patients by the Chadian National Guinea Worm Eradication Program (PEVG), from 2019 to 2020, and supplemented by those contained in the registers of previous years. The analyzes were carried out in N'Djamena, between July and November 2021, within the Laboratory of the Faculty of Medicine.

Methodology: The census of patients was carried out during a survey from 2019 to 2020 by PEVG. These data have been supplemented by those contained in the registers of previous years. Data were first stored in a Microsoft (Excel 2007 Software) spreadsheet, then transferred to the SPSS version 20.0 Software, after removal of outliers and input errors. The Chi-Square test (χ2) made it possible to compare the percentages at the threshold of p<0.005.

Results: In summary it appeared that 52.4% of the patients were 5 to 20 years old, 62% were female, 90.48% lived in Bogam, 95.2% used dirty water from ponds and traditional wells, 33% were farmers, and 33% were breeders. In addition, most of the patients became infected between March and November 2018. The following risk factors combined could explain the Bogam 2019 dracunculiasis outbreak namely: cohabitation with infested pets coming into contact with water, the behavior of young and active people with respect to water, consumption of unhygienic water, gender, lack of containment of some patients that could enter water barefoot, period extending from April to September.

Conclusion: This work highlighted the obvious role of pets as a reservoir on the one hand, and the effectiveness of the PEVG in the fight against dracunculiasis through a treatment protocol combining a wet bandage associated with oral diclofenac + amoxicillin + paracetamol.