New frontiers in applied veterinary point‐of‐capture diagnostics: Toward early detection and control of zoonotic influenza

Abstract

Among the chief limitations in achieving early detection and control of animal‐origin influenza of pandemic potential in high‐risk livestock populations is the existing lag time between sample collection and diagnostic result. Advances in molecular diagnostics are permitting deployment of affordable, rapid, highly sensitive, and specific point‐of‐capture assays, providing opportunities for targeted surveillance driving containment strategies with potentially compelling returns on investment. Interrupting disease transmission at source holds promise of disrupting cycles of animal‐origin influenza incursion to endemicity and limiting impact on animal production, food security, and public health. Adoption of new point‐of‐capture diagnostics should be undertaken in the context of promoting robust veterinary services systems and parallel support for operationalizing pre‐authorized plans and communication strategies that will ensure that the full potential of these new platforms is realized.

The potential of diagnostic point‐of‐care tests (POCTs) for infectious and zoonotic animal diseases in developing countries: Technical, regulatory and sociocultural considerations

“…Loth et al ( 2008 ) conducted field testing of two LFAs for detection of HPAI in oropharyngeal swabs taken from free‐ranging village chickens in Indonesia, and PCR testing on replicate swabs confirmed diagnostic sensitivities and specificities of the POCTs as 69%–71% and 98%, respectively. More recently, a Vietnamese pilot study reportedly took portable nucleic acid extraction and insulated isothermal PCR platforms into live bird markets to conduct rapid, on‐the‐spot testing of oropharyngeal swabs from poultry for detection of HPAI (Schar et al., 2019 ). A LFA for the detection of PPR virus in ocular and nasal swabs was trialled in field sites in Pakistan, Ethiopia, Ivory Coast and Uganda, and the test results obtained within 15–30 min reported diagnostic sensitivity and specificity of 84% and 95%, respectively, compared to PCR (Baron et al., 2014 ).…”

“…While costs of individual tests can be higher for POCTs compared to high‐throughput laboratories, POCTs are likely to appeal to government veterinary services in LMICs due to their lower initial purchase price, as well as decreased ongoing costs for operation, maintenance and personnel training. Modifying testing strategies where appropriate can provide additional savings, such as pooling of samples to reduce numbers of test runs; this was successfully implemented in Vietnamese live poultry markets, in which oropharyngeal swabs from five birds were pooled for testing with HPAI POCTs, at a cost of $10 USD per test run (Schar et al., 2019 ). Other considerations include costs of manpower, equipment and reagent storage, and transport for veterinary staff implementing POCTs in the field.…”

“…Animal rearing, slaughter, preparation and food consumption practices in many LMICs can further promote transmission of infectious animal and zoonotic diseases. Throughout Asia for example, live “wet” animal and seafood markets facilitate high‐density mixing of people and multiple domestic and wild animal host species from diverse geographical locations and can drive transmission, amplification and recombination of circulating viruses that may give rise to new strains with pandemic potential (Offeddu et al., 2016 ; Schar et al., 2019 ), including zoonotic swine‐ and avian‐origin influenzas and the more recent novel coronavirus SARS‐CoV‐2 (WHO, 2020b ).…”

Optimizing the early detection of low pathogenic avian influenza H7N9 virus in live bird markets

“…at the time of the highest within-LBM prevalence of infection, as predicted by the model. (3) The portable PCR surveillance strategy (strategy 3): this second alternative strategy is similar to strategy 1 except that all samples are directly analysed on site for the H7 gene using the portable PCR device [25,26], assuming an average delay of 7 h between sampling and diagnostic test result communication. (4) The optimized portable PCR surveillance strategy (strategy 4):…”

“…All samples were transported to an official diagnostic laboratory where they were consecutively screened for M, H7 and N9 genes using RT-PCR. As an alternative to this surveillance strategy, a portable PCR device has been introduced recently to improve H7N9 detection and response capacities in Vietnam [25,26]. This device can be directly deployed in LBMs and allows virus detection within 7 h after sampling, while the laboratory-based surveillance protocol takes on average 72 h due to logistic reasons.…”