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Field Postmortem Rabies Rapid Immunochromatographic Diagnostic Test for Resource-Limited Settings with Further Molecular Applications

Functional rabies surveillance systems are crucial to provide reliable data and increase the political commitment necessary for disease control. To date, ...

Direction des Services Vétérinaires

Ecole Inter Etats de Sciences et de Médecine Vétérinaires de Dakar

Brucellosis is a zoonosis of economic and public health concern. While most diagnostic tests for brucellosis can only be performed in the laboratory, the Fluorescence Polarization Assay (FPA) was developed as a rapid point-of-care field test. This pilot project aimed to validate the use of FPA for rapid diagnosis of ruminant brucellosis on the field, and to compare the FPA performance with that of the more commonly used Rose Bengal Test (RBT). Blood samples were first collected from ruminants in a livestock market, and later from a nearby slaughterhouse in Port Bouët, Abidjan, Côte d'Ivoire. Samples collected in the livestock market were processed and tested with the FPA in a central laboratory, while samples collected in the slaughterhouse were processed immediately and the FPA was performed on site. To assess the FPA intra-test agreement, a portion of the serum samples tested at the slaughterhouse were re-tested with the FPA in the laboratory later the same day. To assess inter-test agreement, all serum samples were retested with the RBT. A total of 232 samples were tested with the FPA, 106 and 126 from the livestock market and slaughterhouse, respectively. Of these, 26 tested positive and 39 were doubtful for brucellosis. The FPA was repeated on 28 of the samples collected at the slaughterhouse, and comparison of results indicated a moderate intra-test agreement (Kappa = 0.41). The agreement improved when the doubtful category was treated as negative (Kappa = 0.65), and when cattle were excluded (Kappa = 0.56 to 0.61). The RBT was performed on 229 samples, and of these 10 tested positive. A comparison of FPA and RBT results indicated poor agreement (Kappa = 0.00); this improved to slight when only samples taken at the livestock market and tested in the laboratory were considered (Kappa = 0.14). The FPA did not perform well in tropical field conditions, possibly due to the high ambient temperatures in the slaughterhouse. Moreover, a difference in performance was noted in relation to the species tested, whereby the FPA seemed to perform better on sheep and goat samples, compared to cattle samples. These findings highlight that further adjustments are needed before implementing the FPA on the field.

Evaluation of the Fluorescence Polarization Assay as a Rapid On-Spot Test for Ruminant Brucellosis in Côte d'Ivoire.

Rabies is endemic in Côte d'Ivoire and was identified in January 2017 as a priority zoonosis by all stakeholders in public health. A well-designed integrated national rabies control is essential to attain the objective of zero human deaths from dog rabies by 2030. The current study describes the complementary elements of dog bite risk factors and the dog population estimate that are relevant for planning sustainable interventions. We conducted a transverse survey in 8'004 households in the departments of San Pedro (4'002) and Bouaké (4'002), covering both rural and urban areas. The dog-household ratio was estimated at one dog for three households (0.33) or one dog for 20 people (0.05). The owned canine population on a national level was estimated at 1'400'654 dogs (range 1'276'331 to 1'535'681). The main dog bite risk factors were dog ownership, being male, and living in urban San Pedro Department. The results lay a foundation for public engagement and further steps for mass vaccination of the household dog population to reach vaccination coverage of at least 80%. Stakeholders further recommend raising awareness of dog owners, reinforcing knowledge in school children and young boys, and behavior changes towards domestic animals.

Vessaly Kallo

Direction des Services Vétérinaires

Field Postmortem Rabies Rapid Immunochromatographic Diagnostic Test for Resource-Limited Settings with Further Molecular Applications