White Spot Syndrome Virus and the Caribbean Spiny Lobster, Panulirus argus: Susceptibility and Behavioral Immunity

Abstract

2 The Caribbean spiny lobster Panulirus argus is susceptible to infection by Panulirus argus Virus 3 1 (PaV1), the only virus known to naturally infect any lobster species. However, P. argus is able 4 to mitigate PaV1 transmission risk by avoiding infected individuals. White Spot Syndrome Virus 5 (WSSV) has a particularly wide host range. WSSV has not been documented in wild 6 populations of spiny lobsters, but has been experimentally transmitted to six other lobster 7 species from the genus Panulirus spp. While WSSV has been detected intermittently in wild 8 populations of shrimp in the Caribbean region, the risk to P. argus has not been evaluated.9 Potential emergence of the disease could result in fisheries losses and ecological disruption.10 To assess the risk to P. argus, we tested its susceptibility to WSSV via injection and waterborne 11 transmission. We also tested whether healthy lobsters can detect and avoid conspecifics with 12 qPCR-quantifiable WSSV infections. We found P. argus to be highly susceptible to WSSV via 13 intramuscular injection, with mortality reaching 88% four weeks post inoculation. Panulirus 14 argus was also susceptible to WSSV via waterborne transmission, but WSSV burden was low 15 after four weeks via qPCR. Behavioral assays indicated that P. argus can detect and avoid 16 conspecifics infected with WSSV and the avoidance response was strongest for the most 17 heavily infected individuals -a response comparable to PaV1-infected conspecifics.18 Panulirus argus is the first spiny lobster found to be susceptible to WSSV in the Americas, but it 19 is possible that a generalized avoidance response by healthy lobsters against infected 20 conspecifics provides a behavioral defense and may reduce WSSV infection potential and 21 prevalence. Such avoidance may extend to other directly transmitted pathogens in spiny lobster 22 populations preventing them from becoming common in their population. 24Author Summary 25 Erica P. Ross is a PhD candidate at the University of Florida, studying the disease ecology of the 26 Caribbean spiny lobster, with a focus on chemosensory ecology. Donald C. Behringer is an 27 associate professor at the University of Florida and his research focuses on disease ecology, 28 epidemiology, and fishery ecology, with a focus on crustaceans and other marine invertebrates.29 Jamie Bojko received his PhD from the University of Leeds and is currently a post-doctorate 30 associate at the University of Florida studying experimental and systemic crustacean pathology. 31 35 globe. WSSV has resulted in mass mortality and economic loses of > 3 billion USD (US dollars), 36 annually [1, 2]. The virus can infect all species of penaeid shrimp and over 40 other species of 37 Crustacea (e.g., crabs, crayfish, and lobsters), with some studies showing successful 38 transmission to other arthropods, such as insects [3 -5]. WSSV has had its greatest impact on 39 aquaculture populations, but some screening studies have identified the virus in crustacean hosts 40 outside of aquaculture facili...

Double-Stranded RNA Binding Proteins in Serum Contribute to Systemic RNAi Across Phyla—Towards Finding the Missing Link in Achelata

“…These species are closely related, which would suggest that RNAi may work in O. mosambicus , however our trend correlates in vivo exogenous RNAi and dsRNA binding of the serum, not in vitro RNAi. The lack of dsRNA binding proteins in the O. mosambicus serum may prevent in vivo exogenous RNAi from functioning, however in a cell culture system where dsRNA transport is not a limiting factor, RNAi is applicable [ 50 ]. This may also be the case in S. lalandii , where an identical gel response was observed ( Figure 4 A).…”

Double Stranded RNA Binding Proteins in the Serum Contribute to Systemic RNAi across Phyla – Towards Finding the Missing Link in Achelata

“…The exo-siRNA pathway is antiviral in nature and represents a major pathogen defence mechanism in invertebrates, and if this has been hindered in spiny lobster species, they should be highly susceptible to viral infection. Interestingly however, only a single virus has ever been isolated from any spiny lobster which suggests a powerful antiviral immune system [58,59]. The contradiction of powerful antiviral mechanisms and a lack of an RNAi response indicates that other mechanism to deal with viruses must exist within spiny lobsters.…”