2.1 Malaria parasites
Plasmodium relictum (lineage SGS1) is the most prevalent agent of
avian malaria in Europe (Valkiunas, 2004). The parasite strain used in
the first experiment was isolated from an infected Great tit
(Parus major ) in Lausanne, Switzerland in June 2018. Since then,
the parasite has been maintained by carrying out regular passages across
a stock canaries (Serinus canaria ) through intraperitoneal
injections (i.p) until the experiment (November 2018, Pigeault et al.,
2015). The Plasmodium relictum strain (lineage SGS1) used in the
second experiment was isolated two months before the experiment (January
2019) from an infected House sparrow (Passer domesticus ) captured
in the field and passaged to naïve canaries by i.p.
Prior to the experimental infection, a small amount (ca.3-5 µL) of blood
was collected from the medial metatarsal vein of each canaries to ensure
that they were free from any previous haemosporidian infections. Three
and four birds, for the experiment one and two respectively, were then
inoculated by intraperitoneal injection of 100µL of an infected blood
solution. Blood solution was constituted with a mixture of PBS and blood
(ratio 1:1) sampled from 3 canaries infected with the parasite three
weeks before the experiment. Ten days post-infection, bird parasitaemia
(percentage of infected red blood cell) was estimated by visual
quantification on blood smears (Valkiunas, 2004).