Ecological and physiological effects of PaV1 infection on the Caribbean spiny lobster (Panuhrus argus Latreille)

Pathogens can profoundly impact the ecology of the organisms they infect through changes in host behavior that influence demographic processes. For example, juvenile Caribbean spiny lobsters (Panulirus argus Latreille) infected with the PaV1 virus (Panulirus argus Virus 1) are avoided by their normally social conspecifics, which alters local spatial distributions and presumably rates of disease transmission. PaV1 infections are nearly always lethal, but prior to succumbing to the disease, infection may impact other host dynamics (e.g., movement, growth, or survival) that effect transmission of the virus. We used mark-recapture surveys and laboratory studies to determine the impact of PaV1 infection on lobster movement and physiological condition, and in turn, the effect of condition on susceptibility to infection. Significantly more healthy lobsters were recaptured than heavily diseased lobsters in 5-d mark-recapture surveys, indicating either greater emigration or greater mortality of infected lobsters. Results of a laboratory bioassay suggest that lobsters with early-stage infections moved at an equivalent rate to healthy lobsters, however, as infection progressed, lobsters inoculated with PaV1 moved less than healthy lobsters ultimately remaining sedentary. Infected lobsters captured in nature also had significantly lower hemolympb (blood) serum protein values, indicating poor physiological condition. However, poor condition did not predispose lobsters to greater risk of infection because prevalence was not different between starved lobsters and healthy lobsters challenged with PaV1. Although lobsters infected with PaV1 eventually become sedentary and of poor nutritional condition, during the early stages of infection they remain active and are thus capable of dispersing the virus throughout the population. (c) 2008 Elsevier B.V. All rights reserved.