Keys to the avian malaria parasites

Abstract

BackgroundMalaria parasites (genus Plasmodium) are widespread in birds. These pathogens cause pathology of blood and various organs, often resulting in severe avian malaria. Numerous recent studies have reported DNA sequences of avian malaria parasites, indicating rich genetic diversity and the possible existence of many undescribed species. However, the majority of reported Plasmodium lineages remain unidentified to species level, and molecular characterization is unavailable for the majority of described Plasmodium parasites. During the past 15 years, numerous new Plasmodium species have been described. However, keys for their identification are unavailable or incomplete. Identification of avian malaria parasites remains a difficult task even for experts, and this precludes development of avian malariology, particularly in wildlife. Here, keys for avian malaria parasites have been developed as a baseline for assisting academic and veterinary medicine researchers in identification of these pathogens. The main obstacles and future research priorities have been defined in the taxonomy of avian Plasmodium species.MethodsThe data were considered from published articles and type and voucher material, which was accessed in museums in Europe, the USA and Australia. Blood films containing various blood stages of the majority of described species were examined and used for the development of dichotomous keys for avian Plasmodium species.ResultsIn all, 164 published articles were included in this review. Blood stages of avian Plasmodium parasites belonging to subgenera Haemamoeba, Giovannolaia, Novyella, Bennettinia and Huffia were analysed and compared. Illustrated keys for identification of subgenera and species of these parasites were developed. Lists of invalid and synonymous Plasmodium parasite names as well as names of doubtful identity were composed.ConclusionThis study shows that 55 described species of avian Plasmodium can be readily identified using morphological features of their blood stages. These were incorporated in the keys. Numerous synonymous names of Plasmodium species and also the names belonging to the category species inquirenda exist, and they can be used as reserves for future taxonomy studies. Molecular markers are unavailable for 58% of described Plasmodium parasites, raising a task for the current avian malaria researchers to fill up this gap.

A new blood parasite of leaf warblers: molecular characterization, phylogenetic relationships, description and identification of vectors

“…This is not characteristic of the great majority of haemosporidian parasites, in which the cytoplasm of macrogametocytes stains more intensively than in microgametocytes (Fig. 4 ) [ 59 ].…”

Population structure of avian malaria parasites

“…Additionally, we recovered a suspected introgressed parasite in Refugio Boquerón, PR, where OZ01 has not been detected (it has been detected at very low abundances in other locations on Puerto Rico, see Figures and ), making it less likely to be a coinfection in this case. The lineages assessed here have not yet been assigned to morphospecies (Malavi database, Bensch et al., ), and a morphological assessment of lineages OZ01 and OZ04 following the protocols and keys described in Valkiūnas, Iezhova, Loiseau, and Sehgal () and Valkiūnas and Iezhova () revealed no discernible difference between lineages. As a result, coinfections could not be identified or ruled out at present by inspecting blood smears.…”

“…OZ04 OZ14 Bensch et al, 2009), and a morphological assessment of lineages OZ01 and OZ04 following the protocols and keys described in Valkiūnas, Iezhova, Loiseau, and Sehgal (2009) and Valkiūnas and Iezhova (2018) revealed no discernible difference between lineages.…”

Evaluation of Avian Malaria in An Inter-Andean Dry Forest of Imbabura Province in Ecuador

“…An optical microscope (Leica DM 300 model) set at 1000x with immersion oil was used to determine parasitaemia and parasite, merozoite/ring, and schizont stages [1]. Valkiūnas, Iezhova, and collaborators have presented recommendations for the identification of avian malaria on smears under the light microscope [1,20].…”

“…The fields of view in the microscope contained around 200 RBC/field in each sample. We calculated the percentage of parasitaemia as the number of infected RBC per 100 cells [20,21].…”