Searching for blood parasites in Magellanic penguins (Spheniscus magellanicus) along the Patagonian coast

RALPH ERIC THIJL VANSTREELS; MARCELA UHART; MARCOS AMAKU; VIRGINIA RAGO; CLAUDIA NIEMEYER; SUSAN KUTZ; JOSÉ LUIZ CATÂO-DIAS

Lyon

Conferencia; 61th Wildlife Diseases Association (WDA) EWDA conference,; 2012

Wildlife Diseases Association

Magellanic penguins (Spheniscus magellanicus) are susceptible to blood parasites in captivity; it is not clear however whether these parasites infect the species’ wild populations. From 24 to 27 January 2012 we studied 140 adult Magellanic penguins in the Argentinean Patagonia (n = 35 animals per colony): La Ernestina, Punta Tombo, Cabo Dos Bahías, and Caleta Malaspina (Bahía Bustamante). Blood was collected from the jugular vein and two thin blood smears were prepared, fixed in methanol and stained with Wright-Rosenfeld and Giemsa. A minimum 30000 erythrocytes per animal were examined under 1000x magnification. No blood parasites were observed. Sensitivity estimates of blood smear examination for the detection of avian blood parasites range from 52% to 81%. Blaker’s ConfidenceInterval estimated that prevalence of blood parasites must have been ≤ 3.4% (test sensitivity = 75%). In a worst-case scenario (test sensitivity = 50%), prevalence must have been ≤ 5.1%; in a best-case scenario (test sensitivity = 90%), prevalence must have been ≤ 2.8%. Combining data from this and published studies, we found that todate 494 Magellanic penguins were examined and found to be negative in Patagonia; overall prevalence may be estimated to be below 1.0% (worst-case: 1.4%; best-case: 0.8%). The fact that no blood parasites have yet been observed in free-ranging penguins in Patagonia suggests that, if they do occur, prevalence must be considerably low and/or spatiotemporally heterogeneous.