FISHERY BULLETIN: VOL. 69, NO. 3 



homolog'ize them with vertebrate factors. The 

 terms merely indicate the type of activity pro- 

 duced. 



DISEASES OF CRUSTACEA 



An imjiressive array of disea.^es atnictinjr the 

 Crustacea has been described (summarized in 

 Sindermann, 1970, and Bang, 1970). A number 

 of these diseases are of microbial etiology, and 

 Koch's postulates have been satisfied for several 

 of them. Some of the published reports con- 

 cerning crustacean diseases include information 

 about host defenses against infection, others do 

 not. The literature also contains information 

 about a variety of experimentally induced infec- 

 tions in Crustacea, many of them produced by 

 microorganisms not known as pathogens in 

 natural populations. Such experimental studies 

 have been pai-ticularly useful in elucidating pos- 

 sible internal defense mechanisms — augmenting 

 studies with known pathogens. The following 

 summary is just that and is not intended as a 

 detailed treatment of crustacean diseases. Some 

 general background information on known di- 

 seases seems important, however, to any con- 

 sideration of internal defense mechanisms. 



The only virus disease of invertebrates re- 

 ])orted in the scientific literature is one that oc- 

 curs in crabs, Portunus dejmrator, on the French 

 Mediterranean coast (Vago, 1966). Disease 

 signs mentioned in his very brief paper included 

 progressive darkening of the exoskeleton, paral- 

 ysis, and death. 



Bacterial infections of various Crustacea have 

 been described, beginning with a disease of beach 

 hoppers on the French coast caused by lumines- 

 cent bacteria (Giard and Billett, 1889). Exper- 

 imental infections were obtained by injecting 

 cultured microorganisms, and some of the crus- 

 tacean species tested exhibited varying degrees 

 of resistance to experimental infection. Another 

 luminescent disease was reported in sand fleas 

 (Talorchestia longicornis and Orchestia pluti- 

 nus) from Woods Hole, Mass., by Inman (1927) . 

 Luminiscent bacilli were cultured, and experi- 

 mental infections obtained. Luminiscent bac- 

 teria were also isolated from the digestive tracts 

 of nonluminous sand fleas. A bacte)'ial disease 



of Gammarus mariiuis was reported from Eng- 

 land by Tait (1917), in which signs of disease 

 included change in color of the infected ami^hi- 

 pods from brown to opaque .vellowish-white, re- 

 duction in numbers of blood cells, and absence 

 of coagulation of hemolymph. Among the larger 

 decapod Crustacea, a severe bacteria! disease of 

 lobsters caused by gram-po.-itive cocci, Gnffkya 

 hoinari,- was recognized in 1947 (Snieszko and 

 Taylor, 1947) and has been the subject of in- 

 tensive studies since then (to be considered in 

 detail later in this iKijjer). Experimental in- 

 fections and resultant mortalities of blue crabs, 

 CalUnectes sapidua, from Chesapeake Bay were 

 reported by Krantz, Colwell, and Lovelace 

 (1969) withVibrio panthenwlyticns. The micro- 

 organism has been isolated from mollusks, fishes, 

 and sediments in various parts of the world and 

 is known as a cause of human gastroenteritis in 

 the Orient. Additionally, several exam])les of 

 "shell disease" — erosion of the exoskeleton by 

 chitin-destroying bacteria — are known in lob- 

 .sters, crabs, and shrimps (Hess, 1937; Rosen, 

 1967. 1970; Anderson and Conroy, 1968). 



Fungus diseases of Crustacea are surijrisingly 

 numerous in reports dating back to Metchnikofl" 

 (1884), who described fatal infections of Daph- 

 nia caused by Monofijiora hiciisjiidata and who 

 first emphasized the crucial role of phagocytosis 

 in determining the outcome of infection. A 

 yeast infection in sand hoppers, Talitrus, from 

 the coast of France, was reijorted by Herrmann 

 and Canu ( 1891 ) . Experimental infections from 

 exposure to cultured microorganisms were fatal 

 to Tttlitriis in 20 to 2.5 days. Phagocytosis was 

 marked in such infections, and the hemolymph 

 became milky in advanced cases. Crabs (Car- 

 cinus niaenofs) , jirawns (Paluemonetes varimis) , 

 and crayfish (Astacus fiiiriatulis) were not sus- 

 ceptible to the experimenUil infections. Pixell- 

 Goodrich (1928) descriljed another yeast infec- 

 tion which was epizootic in ddnimano; from a 

 stream in England. The pathogen Cryptococciis 

 (jammarl repi'oduced in the hemolymph and 

 rendered it milky in color, coagulation was re- 

 tarded, and heavil.v infected individuals died. 

 Phagocyto.sis was active and sometimes success- 

 ful in overcoming infections. Hypertrophy of 

 fixed phagocytic cells was common. 



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