Blood Parasites in Birds From the Lowlands of Northern Colombia

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88 A. LODOÑO ET AL. FIG. 1. Studies for haematozoa in Colombian birds. Numbers 1, 2, 3 refer to localities in the text. We sampled a dry forest patch (c. 2 ha) surrounded by secondary forest remnants, croplands and villages. Sites 1 and 2 are at 70 m a.s.l with annual mean temperature of 28°C, and annual rainfall of 200 cm. Site 3. El 16, S of Zaragoza municipality (07°3044N, 74°5114W), east bank of Nechí river at 55 m a.s.l, with a mean annual temperature of 28°C and annual rainfall of 307.5 cm. We worked on a c. 10 ha fragment with secondary and mature forest (25-30 m tall), close to Tafur marsh and San Nicolas watershed. Wild birds were mist-netted between 06: 00 h and 13:00 h, and domestic birds were captured by hand between 14:00 and 17:00 h in rural housing near the mist-netting sites. Two or three blood smears per bird were taken from a drop of blood from the brachial vein using capillary tubes. Smears were fixed in 100% methanol after air drying, and then were stained with Giemsa (pH 7.0 for 40 min) on the same day. Blood films were first examined under low power (10× and 20×) for microfilariae and trypanosomes, covering all regions of the smear, and then under oil immersion
BLOOD PARASITES OF COLOMBIAN BIRDS 89 (100×), counting smaller haematozoa in 100 microscopic fields (which exceeds the minimum number of erythrocytes required for this kind of diagnosis) (Godfrey et al. 1987). To avoid wrong determination of Plasmodium spp. and Haemoproteus spp. due to similarities in their sexual forms, Plasmodium spp. was identified by the presence of both schizonts and round or enlarged gametocytes in the blood smear, while infections by Haemoproteus spp. are characterized by the presence only of enlarged (halteridium) or round gametocytes in peripheral blood. AL and SB independently analyzed all blood smears with similar results. The collection of samples was kept at the Malaria Group in the Faculty of Medicine of University of Antioquia. Finally, comparisons of percentages of parasitism were made by 2 test (EpiInfo version 6.1), and values of p < 0.05 were considered as significantly different. Our nomenclature of birds follows the South American Check list Committee (SACC, Remsen et al. 2004). RESULTS In total, 302 birds (75 species of 24 families) were examined for blood parasites (Table 1). From the municipality of Turbo (sites 1 and 2), blood smears of 140 wild birds (20 families and 52 species) and 50 domesticated birds (5 families and 5 species) were examined. From the municipality of Zaragoza (site 3), we examined smears of 63 wild birds of 32 species (11 families) and 49 domesticated birds of two species (two families). Among wild birds, the families Tyrannidae and Thamnophilidae were the most frequent. Twenty-eight birds (9.3%) of 16 species harbored at least one genus of parasite. Plasmodium, present in 5.6% of all birds, was the most frequent haematozoa, followed by Haemoproteus (2.6%), Leucocytozoon (0.3%) and microfilariae (1.0%) (Table 1). Parasites were most frequent in passerine birds (81.2% of all infected). None of the seven Nearctic- Neotropical migratory songbirds harbored parasites (Table 1). To our knowledge, four species were examined for haematozoa for the first time (Sakesphorus canadensis, Myrmotherula fulviventris, Myiodinastes chrysocephalus and Formicivora grisea) (sensu White et al. 1978, Woodworth-Lynas 1989, Bennett et al. 1991, Young et al. 1993 and all the former Colombian studies). New host-parasite records include White-fringed Antwren (Formicivora grisea) with Plasmodium spp., Buff-throated Foliage-gleaner (Automolus ochrolaemus) with Leucocytozoon spp., Tawny-throated Leaftosser (Sclerurus mexicanus) and the Bicolored Wren (Campylorhynchus griseus) with microfilariae. Only two species: the Tawny-throated Leaftosser and the Bananaquit (Coereba flaveola) had multiple infections in both zones (Table 1). Comparison of total prevalence showed a pattern similar to other reports in Neotropics. Also non significant differences were observed between prevalence of haematozoa in wild and domesticated birds. Differences were observed at the level of genus of parasite when separating wilds from domesticated and comparing with data filtered from White et al. 1978; Plasmodium spp. was significantly more abundant in our sample of domesticated (p = 0.0012) and Haemoproteus spp. was lower in our sample of wild birds (p = 0.0317). No significant differences for prevalence of infected birds were observed between Turbo (sites 1 and 2) and Zaragoza (site 3). In Turbo, Haemoproteus was the most frequent genus of parasite, being present in seven of 14 infected wild birds, and Plasmodium was the most common in domesticated species (5 of 5). In Zaragoza, Plasmodium was the most frequent in both domestic and wild birds, and Haemoproteus was not found. The birds infected with Haemoproteus spp. had relatively high parasitaemia (more than 2 gametocytes/100 erythrocytes), while in those infected with Plasmodium spp. the parasitaemia was lower and in the remaining infections, only one to three parasites were seen in the smears. DISCUSSION The prevalence of blood parasites (9.3%) in our study was significantly low compared with the nearest continental land mass (37% in Neartic, p < 0.0001, White
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Blood Parasites in Birds From the Lowlands of Northern Colombia

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