From Field Tests to Molecular Tools-Evaluating Diagnostic Tests to Improve Rabies Surveillance in Namibia

Abstract

Rabies is endemic in Namibia and is present both in wildlife carnivores and domestic free-roaming dogs. The disease thus represents a challenge for public human and veterinary disease control. Namibia has implemented a national strategic plan to control rabies and the country's activities are supported by international organizations. To this end, rabies diagnosis at the Central Veterinary Laboratory (CVL) was improved in the frame of a World Organization for Animal Health (WOAH) laboratory twinning program: from practical sampling techniques and the use of lateral flow devices to a novel universal and discriminatory quantitative real-time Reverse transcription polymerase chain reaction (RT-qPCR), which easily identify dog-associated rabies viruses. The procedures applied and the results can be used as a template to improve rabies laboratory diagnosis.

Keywords: Africa; Namibia; RT-qPCR; lateral flow devices (LFD); rabies diagnostics; surveillance.

Figure 1

Number of submitted samples for rabies diagnosis in Namibia from 2018–2021 (a) and the positivity rate based on FAT (b); mean and 95% confidence intervals are indicated). Number of rabies positive samples per species (c) and number of submissions within the time period (d).

Figure 2

Data for Anigen/Bionote LFD performance in comparison with FAT for samples arriving at CVL (a) and samples from the field (b) between 2019–2021. The resulting sensitivity and sensitivity are shown (c) with 95% confidence intervals indicated.

Figure 3

Comparison of the DogF1 assay with the standard FLI method (R13/14) and the mean of differences (a) and a linear regression analysis (b), display of DogF1 positives and negatives from R13/14 positives per region (c) and per species (d). Livestock include samples from cattle, sheep and goats.