Evaluation of the diagnostic accuracy of lateral flow devices as a tool to diagnose rabies in post-mortem animals

Abstract

Implementation of lateral flow devices (LFDs) for rabies antigen detection is expected to improve surveillance through the efficient detection of rabid animals in resource-limited settings; however, the use of LFDs for diagnosis remains controversial because some commercially available kits show low sensitivity. Therefore, we compared the diagnostic efficacy of three LFDs (ADTEC, Bionote, and Elabscience kits) paralleled with the direct fluorescent antibody test (dFAT) using fresh samples and investigated the diagnostic accuracies. To do so, we evaluated rabies-suspected samples submitted to the Regional Animal Disease Diagnostic Laboratory III, Philippines. Furthermore, we conducted real-time RT-PCR and sequencing to measure the accuracy of field laboratory diagnosis. The total number of animals submitted during this study period was 184 cases, including negative control samples. Of these, 53.9% (84 cases) were positive in the dFAT. Dogs were the most common rabies-suspected animal (n = 135). The sensitivities of the ADTEC and Bionote kits were 0.88 (74 cases) and 0.95 (80 cases), respectively. The specificity of both kits was 1.00 (100 cases). Furthermore, the sensitivity and specificity of the ADTEC kit after directly homogenizing the samples in assay buffer without dilution in phosphate-buffered saline (ADTEC kit DM) were 0.94 (79 cases) and 1.00 (100 cases), respectively. By contrast, there were no positive results using the Elabscience kit among all dFAT-positive samples. The sensitivity and specificity of LFDs make these tests highly feasible if properly used. Therefore, LFD tests can be used to strengthen the surveillance of rabies-infected animals in endemic and resource-limited settings.

Background and descriptive features of rabies-suspected animals in Central Luzon, Philippines

“…This is the main obstacle to the establishment of additional facilities. Simple, rapid, and low-cost methods such as LFD can be used to establish a diagnosis in a small laboratory in a remote area or in the field [9,11]. This novel diagnosis can be a solution to promote animal surveillance.…”

“…We conducted a prospective observational study of suspected rabid animals to evaluate the diagnostic accuracy of the lateral flow device (LFD) and investigate the characteristics of rabies animals at RADDL III, a government agency in the Philippines. The details of the study design and setting have been previously described [9]. This regional laboratory receives suspected rabies specimens (heads or carcasses) from Central Luzon (Region III) (Fig.…”

“…We conducted semi-structured interviews to collect detailed information about the animal, owner, and bite victims using a standard questionnaire [8,9]. The research staff interviewed, directly or telephonically, the owners or those who sent the animal head or carcass.…”

“…Briefly, touch impressions of small transverse sections (2-3 mm in thickness) of the hippocampus, brain stem, and cerebellum were stained with fluorescein isothiocyanateconjugated anti-rabies monoclonal antibody (Fujirebio, Malvern, PA, USA; lot No. 309303) according to the standard operating procedure [8,9]. The stained samples were examined under an epifluorescence microscope (E200, Nikon, Tokyo, Japan) to confirm the presence of the rabies virus antigen by two independent examiners.…”

Eliminating dog-mediated rabies: challenges and strategies

“…The development of diagnostic infrastructure in countries where the virus is endemic is an economic challenge, however, there are rapid, simple to perform tests that can be undertaken in the field. The Lateral Flow Assay (LFA), which is an indirect ELISA, is a useful diagnostic tool for detection (Kimitsuki et al 2020;Yale et al 2019), with a 94.6% sensitivity compared with the gold standard direct fluorescent antibody test (dFA). Conducting this indirect ELISA test requires minimal training, although the process of sample extraction requires skill; however, field veterinarians could easily be trained in this procedure.…”