The Endemic Copepod Calanus pacificus californicus as a Potential Vector of White Spot Syndrome Virus

Abstract

The susceptibility of the endemic copepod Calanus pacificus californicus to white spot syndrome virus (WSSV) was established by the temporal analysis of WSSV VP28 transcripts by quantitative real-time PCR (qRT-PCR). The copepods were collected from a shrimp pond located in Bahia de Kino Sonora, Mexico, and challenged per os with WSSV by a virus-phytoplankton adhesion route. Samples were collected at 0, 24, 48 and 84 h postinoculation (hpi). The VP28 transcripts were not detected at early stages (0 and 24 hpi); however, some transcript accumulation was observed at 48 hpi and gradually increased until 84 hpi. Thus, these results clearly show that the copepod C. pacificus californicus is susceptible to WSSV infection and that it may be a potential vector for the dispersal of WSSV. However, further studies are still needed to correlate the epidemiological outbreaks of WSSV with the presence of copepods in shrimp ponds.

Comparative paleovirological analysis of crustaceans identifies multiple widespread viral groups

“…Viruses have an important impact on the structure and ecology of phytoplankton communities [ 54 ], and it has recently been suggested they may play an important role in shaping mesozooplankton communities as well [ 38 ]. In addition, there is evidence suggesting that copepods can serve as vectors for transmitting viruses to fish and shrimp, causing important economic losses [ 55 , 56 ], and to phytoplankton, with possible consequences on global biogeochemical cycling [ 57 ]. Despite these major consequences, only one study has characterized viral infections in copepods so far [ 38 ].…”

Pathogens and Passengers: Roles for Crustacean Zooplankton Viruses in the Global Ocean

“…Proposed causes of unexplained zooplankton mortality include environmental stress, starvation, toxin exposure and disease. Viral diseases in some larger crustaceans are well documented [29,30], and some of these viruses are also found in planktonic freshwater and marine crustaceans [31][32][33][34][35][36][37]; however, their impacts are understudied and largely a mystery in hosts that are not harvested for food. Additionally, even though zooplankton are known vectors of aquaculture and phytoplankton pathogens [36][37][38][39][40], the suite of pathogenic viruses harboured by abundant zooplankton is not established.…”

“…In addition to their own viruses, crustacean zooplankton carry and transmit viruses of other organisms. Examples include crustacean zooplankton spreading viruses between phytoplankton [129,130], in aquaculture [36,[38][39][40]69], between wild fish [34,37,131] and to their predators [132]. Of all the marine invertebrate viruses described, those with direct economic impacts on aquaculture have been studied most extensively regarding their disease impacts and modes of transmission [30,50,51,133].…”

Parasites, pathogens, and other symbionts of copepods

“…The sea louse Caligus rogercresseyi vectors the orthomyxovirus (-ssRNA) ISAV (infectious salmon anemia virus) to the salmon host, while more indirect effects also operate; for example, infection of Atlantic salmon by L. salmonis (and other parasitic sea lice) has been shown to increase their susceptibility to ISAV [86]. Viruses of penaeid shrimps are of research interest because of their importance in shrimp aquaculture [87][88][89].…”

“…Copepods have been shown to amplify and vector the dsDNA white spot syndrome virus (WSSV) [87,88], and Taura syndrome virus (TSV) replicates in the copepod Ergasilus manicatus, while yellow head virus (YHV) may also be mechanically vectored to shrimp [89].…”