In vivo WSSV infection models occupy a crucial first step in the research flow that tries to elucidate the infectious disease process to develop new anti-viral treatments. Thus, t he development and use of standardized in vivo infection models is a necessity. This review critically examines key aspects of in vivo WSSV infection model development that are often neglected and that can greatly affect the experimental outcomes.
A review was conducted by retrieving literature from searches of computerized databases, hand searches, and authoritative texts with the overarching purpose to synthesize the existing literature in the field (Sargeant & O’Connor, 2020).
First, standardizing and reporting factors pertaining to the components of the disease triad is crucial, because each component may influence the results of the experiments that are performed (Arbon et al., 2023) . Second, the characteristics of the experimental shrimp can potentially influence the dynamics of disease expression . A characteristic that is very rarely addressed specifically in relation to WSSV infection studies is the ‘shrimp seed quality’. This can vary significantly between shrimp batches, regardless of genetic or geographic origin, which could in turn cause variation between study results. Third, the choice of viral inoculum is important. The inoculum should be specific pathogen free to prevent co-infections that might influence the outcome of the study . Liquid viral stocks can be purified which minimizes potential confounding factors (Dantas-Lima, et al. 2013). Tissue inoculum is cruder and made from unprocessed or minced WSSV-infected tissues. Including a mixing or blending step in the processing procedure is advised. Fourth, the most effective inoculation method is intramuscular injection , but it artificial ly by-passes the host’s natural defense barriers. O ral intubation and intra-bladder inoculation mimic natural transmission routes, but regurgitation and/or perforation are a risks. Inoculations through immersion, cohabitation, or feeding are less invasive, and also represent natural WSSV transmission routes, but they risk being less controllable. Fifth, the housing conditions determine for a large part which information will obtained and possibly also its validity. Individually housing allows for collection of data in a more controlled scientific setting and clinical outcomes can be evaluated individually . G roup housing simulates more closely the on-farm reality of a WSSV outbreak, which might be beneficial for extrapolation to the field.
This research received funding from Flanders Innovation and Entrepreneurship (Belgium).
References:
Arbon, P., et al., (2023). Rev. Aquacult ., 1-19;
Dantas-Lima, J.J., et al., (2013), J. Fish. Dis., 36, 841-851 ;
Sargeant, J. M., et al., (2020). Front. vet. sci. , 7, 502756.