Avian Haemosporidian Diversity on Sardinia: A First General Assessment for the Insular Mediterranean

Abstract

The Western Palearctic is one of the most investigated regions for avian haemosporidian parasites (Haemoproteus, Plasmodium and Leucocytozoon), yet geographic gaps in our regional knowledge remain. Here, we report the first haemosporidian screening of the breeding birds from Sardinia (the second-largest Mediterranean Island and a biodiversity hotspot), and the first for the insular Mediterranean in general. We examined the occurrence of haemosporidians by amplifying their mtDNA cytb gene in 217 breeding birds, belonging to 32 species. The total prevalence of infected birds was 55.3%, and of the 116 haplotypes recovered, 84 were novel. Despite the high number of novel lineages, phylogenetic analysis did not highlight Sardinia-specific clades; instead, some Sardinian lineages were more closely related to lineages previously recovered from continental Europe. Host-parasite network analysis indicated a specialized host-parasite community. Binomial generalized linear models (GLMs), performed at the community level, suggested an elevational effect on haemosporidian occurrence probability (negative for Haemoproteus; positive for Leucocytozoon) likely due to differences in the abundance of insect vectors at different elevations. Furthermore, a GLM revealed that sedentary birds showed a higher probability of being infected by novel haplotypes and long-distance migrants showed a lower probability of novel haplotype infection. We hypothesize that the high diversity of haemosporidians is linked to the isolation of breeding bird populations on Sardinia. This study adds to the growing knowledge on haemosporidians lineage diversity and distribution in insular environments and presents new insights on potential host-parasite associations.

Risk of Infection, Local Prevalence and Seasonal Changes in an Avian Malaria Community Associated with Game Bird Releases

“…We found a quite high prevalence of avian malaria parasites in redlegged partridges in central Spain. The results presented here revealed malaria prevalences that are among the highest found in bird populations, particularly for Plasmodium [4,[65][66][67][68], including studies on species from comparable habitats in Spain [69]. We also found notable differences in the spatial and temporal distribution of parasites at a local scale.…”

“…In general, the absence or low prevalence of hematozoan recorded in many host species inhabiting open and arid environments has been commonly attributed to a reduced transmission rate of parasites due to the scarcity of suitable vectors in those habitats (review in [75]). However, our findings suggest that the abundance of suitable vectors (Culicidae mosquitoes; [69] should not be a limiting factor for the existence and dispersion of malaria parasites in agricultural habitats, at least in our study area (see also [67] for the Mediterranean island of Sardinia). Higher prevalences of these parasites in birds have been found in areas with elevated summer NDVI (a widely used index of vegetal productivity) at the continental level [65], but our study area has a semi-arid climate with very dry summers and consequently is expected to have a low summer NDVI.…”

Prevalence and Genetic Diversity of Avian Haemosporidian Parasites in Southern Iran

“…However, this hypothesises cannot be supported by the data collected in this study, and further studies are needed to clarify this issue. For unclear reasons, we did not find any co-infection of Plasmodium and Leucocytozoon or Haemoproteus and Plasmodium parasites, while co-infections of these parasites are common in wildlife [ 5 , 16 , 62 , 63 , 64 , 65 ]. This might be due to preferable amplification of the DNA of Haemoproteus or Plasmodium parasite lineages in our samples during co-infections [ 66 ].…”

“…Based on the MalAvi database (a Public Database of Malaria Parasites and Related Haemosporidians in Avian Hosts, , accessed on 1 May 2021), over 3600 unique haemosporidian lineages have been reported in about 20% of bird species worldwide. Furthermore, co-infection with two or more different haemosporidian parasites was shown to be common in wild birds [ 6 , 15 , 16 , 17 ].…”

Phylogeographic Patterns of Haemoproteid Assemblages of Selected Avian Hosts: Ecological and Evolutionary Implications

“…For example, the lineage SYAT10, which is according to our study assigned to the Mediterranean ecotype, was also detected in the eastern Mediterranean in Turkey [ 84 ]. Nonetheless, data for key regions of the Mediterranean ecotype, particularly for Greece and Italy, but also data for the oceanic ecotype from the UK, are almost completely lacking for blackcap haemoproteids (but see [ 85 ] for Italy’s Sardinia and GenBank data for the UK). Despite these geographical knowledge gaps, our study suggests that haemoproteids of blackcaps can be divided into two major groups with respect to their phylogeny and geographical affinity: (1) a group of phylogenetically more recent haemoproteids represented mainly by H. parabelopolskyi lineages SYAT01–02 with ranges in western and southwestern Europe and (2) a group of phylogenetically older haemoproteids represented by H. pallidulus lineage SYAT03 and H. homogeneae lineage SYAT16 with ranges in eastern and northeastern Europe.…”