nephrops    blue crab    snow crab

Hematodinium infections have been reported from several crustacean hosts from around the world, with the majority of infections reported in brachyuran crabs (Table 1). The broad range of brachyuran hosts suggests that these parasites are host generalists, with perhaps some species infecting different classes of Crustacea (Amphipoda and Decapoda), but tests of host specificity await refinements in molecular tools. The Hematodinium-like parasite from the spot prawns, Pandalus borealis and P. platyceros (Bower et al. 1993; Meyers et al. 1994, Bower & Meyer 2002) is apparently more closely allied with the Haplosporidia and is not a dinoflagellate (Reece et al. 2000).
Hudson & Shields (1994) and Shields (1994) have speculated that amphipods may act as alternate or reservoir hosts for Hematodinium. Small (2004) recently showed that PCR primers specific for Hematodinium in N. norvegicus also amplify products from amphipods. While these primers indicated that the parasite in amphipods was a species of Hematodinium, they are likely genus specific, making it difficult to draw further conclusions. However, since crustaceans, including amphipods, make up a significant portion of the diet (up to 25%) of juvenile C. sapidus, C. opilio and even N. norvegicus, , and since amphipods reportedly carry a similar infection (Johnson 1986, Small 2004), then their role in transmission of the disease needs to be investigated. Infection trials exposing amphipods to infected tissues or carcasses of infected crabs or lobsters may provide insight into the life cycle of the parasites and potentially elucidate the role of amphipods as reservoir hosts. A similar approach recently uncovered a role for copepods in the life cycle or transmission of Marteilia refringens in oysters (Audemard et al. 2002). Further refinements in PCR-based assays should focus on differentiating between species of Hematodinium, as these will no doubt facilitate identification of alternate or reservoir hosts.

Table 1. Host species infected with Hematodinium or Hematodinium-like parasites.

Group Host species Location Initial reference
Crabs Callinectes sapidus Eastern USA Newman & Johnson 1975
Callinectes similes Eastern USA Messick & Shields 2000
Cancer borealis NY Bight Maclean & Ruddell 1978
Cancer irroratus NY Bight Maclean & Ruddell 1978
Cancer pagurus Bay of Biscay, France Latrouite et al. 1988
Cancer pagurus English Channel Stentiford et al. 2002
Carcinus maenas English Channel Chatton & Poisson 1931
Carcinus maenas Eastern USA Messick & Shields 2000
Chionoecetes bairdi SE Alaska Meyers et al. 1987
Chionoecetex opilio Newfoundland, Canada Taylor & Khan 1995
Chionoecetes opilio Gulf of Alaska, Bering Sea, Chuckchi Sea Meyers et al. 1996
Chionoecetes tanneri British Columbia Bower et al. 2003
Hexapaopeus angustifrons Eastern USA Messick & Shields 2000
Libinia emergenata Eastern USA Sheppard et al. 2003
Liocarcinus depurator Bay of Biscay Chatton & Poisson 1931
Maja squinado Bay of Biscay, France D. Latrouite, unpublished
Menippe mercenaria Eastern USA Sheppard et al. 2003
Necora puber Bay of Biscay, France Wilhelm & Mialhe 1996, Wilhelm & Boulo 1988
Necora puber English Channel Stentiford et al. 2003
Neopanope sayi Eastern USA Messick & Shields 2000, Sheppard et al. 2003
Ovalipes ocellatus NY Bight Maclean & Ruddell 1978
Panopeus herbstii Eastern USA Messick & Shields 2000
Portumnus latipes France Chatton 1952
Portunus pelagicus Moreton Bay, Australia Shields 1992, Hudson & Shields 1994
Scylla serrata Moreton Bay, Australia Hudson & Lester 1994
Trapezia areolata and T. coerulea Great Barrier Reef, Australia Hudson et al. 1993
Lobsters N. norvegicus Eastern Atlantic Field et al. 1992
Amphipods Ampelisca agassizi, A. vadorum, A. verrilli, Byblis serrata, Casco bigelowi, Harpinia propinqua, Letpocheirus pinguis, Melita dentata, Monouclodes edwardsi, Protohaustorius wigley, Phoxocephalus holbolli, Rhepoxynius epistomus Unicola spp.