Haemoproteus iwa in Great Frigatebirds (Fregata minor) in the Islands of the Western Indian Ocean

Abstract

Blood parasites of the sub-genus Haemoproteus have been reported in seabirds, in particular in species in the Suliformes order. These parasites are transmitted by hippoboscid flies of the genus Olfersia; strong specificity has been suggested between the vector and its vertebrate host. We investigated the prevalence of Haemoproteus infection in Suliformes and hippoboscid flies in two oceanic islands of the Western Indian Ocean: Europa and Tromelin. In total, 209 blood samples were collected from great frigatebirds (Fregata minor), masked boobies (Sula dactylatra) and red-footed boobies (Sula sula). Forty-one hippoboscid flies were also collected from birds. Seventeen frigatebirds and one fly collected on Europa tested positive for the presence of Haemoproteus parasites by polymerase chain reaction. Phylogenetic analyses based on partial sequences of the Cytochrome b gene showed that parasites were closely related to Haemoproteus iwa reported from frigatebirds in the Pacific Ocean and in the Caribbean. Plasmodium was also detected in a frigatebird on Europa; however, its placement on the phylogenetic tree could not be resolved. We provide strong support for transmission of blood parasites in seabirds in the Western Indian Ocean and suggest that migrations between the Pacific and the Indian oceans could favor the large-scale distribution of Haemoproteus iwa in frigatebird populations.

Figure 1. Maximum-likelihood consensus tree derived from 33 mitochondrial Cytochrome b nucleotide sequences (478 bp).

Computations were performed with the general time reversible (GTR) nucleotide substitution model, an estimation of the proportion of invariable sites (I = 0.52) and of the nucleotide heterogeneity of substitution rates (α = 1.31). Haemoproteus parasite species, host species and geographic origin are indicated, when available. Two Haemoproteus iwa sequences derived from this study were included and are indicated in red; the sequence obtained from a Haemoproteus parasite detected in a hippoboscid fly is colored in blue. Bootstrap values were reported when higher than 80. Nucleotide sequence accession numbers are indicated in parenthesis.

Figure 2. Maximum-likelihood consensus tree derived from 32 mitochondrial Cytochrome oxydase I nucleotide sequences (698 bp).

Computations were performed with the unequal-frequency Kimura 3-parameter (K81 uf) nucleotide substitution model and an estimation of the nucleotide heterogeneity of substitution rates (α = 1.64). Hippoboscid fly species, host species and geographic origin are indicated. Sequences derived from this study are indicated in red. Nucleotide sequence accession numbers are indicated in parenthesis.

Figure 3. Maximum-likelihood consensus tree derived from 31 mitochondrial Cytochrome b nucleotide sequences (479 bp).

Computations were performed with the general time reversible (GTR) nucleotide substitution model, an estimation of the proportion of invariable sites (I = 0.48) and of the nucleotide heterogeneity of substitution rates (α = 0.52). Plasmodium parasite species, host species and geographic origin are indicated, when available. The Plasmodium sequence derived from this study is indicated in red. Bootstrap values were reported when higher than 80. Nucleotide sequence accession numbers are indicated in parenthesis.