Shields and Squyars: Mortality and hematology of Callinectes sapidus Infected with Hematodinium perezi 



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100 



80 - 



60 



40 - 



20 



Expt 1, control 

 Expt n, control 



10 



15 



20 



25 



30 



35 



40 



C/5 



10 15 20 25 30 



Days after inoculation 



35 



40 



Figure 2 



Survivorship curves for uninfected crabs and crabs infected with H. perezi (high dose=10' 

 parasites/crab, low=10^ parasites/crab). Sample sizes were 22 and 8 uninfected controls; 20 

 (mortality-I experiment), 10 and 10 (high and low dose, mortality-II experiment) respectively. 



hemolymph, uninucleate trophonts) and mortal- 

 ity-II (buffer-washed parasites, vermiform Plasmo- 

 dia) experiments (Tarone-Ware, y}=\.2\ with 1 df, 

 P=0.27), even between different initial doses of the 

 parasite (Fig. 2; Tarone-Ware, x^=0.74 with 1 df , P= 

 0.39). Uninfected crabs (controls) experienced signif- 

 icantly fewer mortalities than did infected hosts ( Fig. 

 3; Tarone-Ware, x^=, 19.27 with 1 df , P<0.001). The 

 controls for the mortality-II experiment did, how- 

 ever, exhibit background mortalities (Fig. 2); but the 

 mortality rate was not significantly different from 



controls in the mortality- 1 experiment (Tarone-Ware, 

 X2=0.65 with 1 df, P= 0.42). None of the control crabs 

 developed infections with H. perezi. Because mortal- 

 ities within treatments were similar between experi- 

 ments, data were grouped for further analysis. 



The median time to death for infected crabs was 

 30.3 ±1.5 (SE) days. Because the controls exhibited 

 few mortalities, the median time to death for the 

 uninfected controls could not be calculated. Infected 

 crabs had a significantly higher mortality rate, seven 

 to eight times greater than that of the uninfected con- 



