Incrimination of natural culicine vectors which transmit Plasmodium elongatum to penguins at the Baltimore Zoo

Abstract

Culex pipiens and Culex restuans were determined to be natural vectors of Plasmodium elongatum which is seasonally transmitted to African penguins (Spheniscus demersus) at the Baltimore Zoo. Breeding sites for both Culex species were identified within a 1.6-km radius of the penguin exhibit. Both species were captured in penguin-baited traps from May to October, with peak biting occurring in July and August. Four of 612 (0.65%) field-collected Culex harbored infective stages of Plasmodium. Both Culex species were highly susceptible to experimental infections of P. elongatum and both were capable of supporting parasite development through the infective sporozoite stage. The course of sporogony of P. elongatum was studied in both Culex species. Experimental transmission of the parasite was achieved using both Culex species.