Avian malaria seroprevalence in Jackass penguins (Spheniscus demersus) in South Africa.

Blood samples of 191 adult Jackass penguins (Spheniscus demersus) from South Africa were tested by indirect enzyme-linked immunosorbent assays (ELISA) with Plasmodium falciparum antigen (R32tet32) for avian malaria antibodies (Ab). The samples originated from free-ranging penguins from offshore islands and southern coast colonies (3 groups, n = 110), from 2 penguin groups (n = 66) rescued after offshore oil-spill contamination and rehabilitated at the Rescue Station of the South African National Foundation for the Conservation of Coastal Birds (SANCCOB) in Cape Town, and from SANCCOB-resident penguins (n = 15). The total average malaria Ab seroprevalence was 39%, and the mean malaria seropositivity ranged from 20% to 62% among the 6 S. demersus groups, with a mean of 55% for oiled penguins, and 31% for the remaining birds. The total mean absorbance value was 0.57 for ELISA-positive penguins, 0.43 for birds kept at SANCCOB facilities, and 0.70 for the penguins from wild colonies. The 2 groups of oiled penguins exhibited higher malaria Ab seroprevalence (38% and 62%) than the 3 groups of non-oiled birds (29%, 33% and 35%). Malaria Ab seroprevalence of free-ranging penguins was significantly lower (P < 0.01) than in the 3 groups of birds at SANCCOB facilities and did not differ significantly among 3 wild penguin colonies.