Lankesterella (Apicomplexa, Lankesterellidae) Blood Parasites of Passeriform Birds: Prevalence, Molecular and Morphological Characterization, with Notes on Sporozoite Persistence In Vivo and Development In Vitro.

Mikas Ilgūnas,Gediminas Valkiūnas,Carolina Romeiro Fernandes Chagas,Dovilė Bukauskaitė,Herbert Weissenböck,Vytautas Preikša,Josef Harl

doi:10.3390/ani11051451

Abstract

Simple SummaryBirds are hosts of various apicomplexan blood parasites, whose blood stages are often similar, resulting in much ongoing debate about the taxonomic and genetic identity of some species. Parasites of several closely related apicomplexan genera can be distinguished mainly by differences in their life cycles in both vertebrate and invertebrate hosts. Recent studies confirmed that some avian blood parasites, which were formerly attributed to the genus Hepatozoon, are genetically closely related to the amphibian parasite Lankesterella minima and might belong to the genus Lankesterella. To understand the distribution and diversity of avian Lankesterella parasites, we examined samples from wild birds, combining molecular genetics and microscopic methods. Experiments which aim for a better understanding of the life cycle of these parasites, and their host specificity, were designed. We demonstrated that avian Lankesterella parasites are more diverse than previously thought, and several species of Hepatozoon described in birds in fact belong to Lankesterella. Two new Lankesterella species parasitizing birds are described, and one species is re-described. This study contributes to a better understanding of diversity and distribution of bird Lankesterella spp. and shows directions for future research on their pathogenicity.Recent studies confirmed that some Hepatozoon-like blood parasites (Apicomplexa) of birds are closely related to the amphibian parasite Lankesterella minima. Little is known about the biology of these pathogens in birds, including their distribution, life cycles, specificity, vectors, and molecular characterization. Using blood samples of 641 birds from 16 species, we (i) determined the prevalence and molecular diversity of Lankesterella parasites in naturally infected birds; (ii) investigated the development of Lankesterella kabeeni in laboratory-reared mosquitoes, Culex pipiens forma molestus and Aedes aegypti; and (iii) tested experimentally the susceptibility of domestic canaries, Serinus canaria, to this parasite. This study combined molecular and morphological diagnostic methods and determined 11% prevalence of Lankesterella parasites in Acrocephalidae birds; 16 Lankesterella lineages with a certain degree of host specificity and two new species (Lankesterella vacuolata n. sp. and Lankesterella macrovacuolata n. sp.) were found and characterized. Lankesterella kabeeni (formerly Hepatozoon kabeeni) was re-described. Serinus canaria were resistant after various experimental exposures. Lankesterella sporozoites rapidly escaped from host cells in vitro. Sporozoites persisted for a long time in infected mosquitoes (up to 42 days post exposure). Our study demonstrated a high diversity of Lankesterella parasites in birds, and showed that several avian Hepatozoon-like parasites, in fact, belong to Lankesterella genus.

Highlights

Blood parasites are extremely common in birds and other vertebrates [1]
Juveniles of Acrocephalidae species were examined, and three of four tested species were positive; A. schoenobaenus was the most prevalently infected species, in both adults and juveniles (Table 2). These are the first reports of Lankesterella parasites in all studied bird species, except for A. schoenobaenus and great tits Parus major
This study suggests that Lankesterella parasites from the Acrocephalidae species would not infect S. canaria belonging to the Fringillidae, and transmission of the same parasite species probably does not occur between birds belonging to different families

Summary

Introduction

Blood parasites are extremely common in birds and other vertebrates [1]. Some of them occur in blood plasma, such as Trypanosoma spp. and microfilariae of filariid nematodes, while others are intracellular (develop in blood cells) [2]. The intracellular parasites are highly diverse and belong to several taxa of the phylum Apicomplexa, such as the orders Haemosporida (e.g., common genera are Plasmodium, Haemoproteus and Leucocytozoon), Piroplasmida (e.g., Babesia, Theileria and Sauroplasma), and Eucoccidiorida, the latter featuring the two suborders Adeleorina (e.g., Hepatozoon, Haemogregarina and Karyolysus) and Eimeriorina (e.g., Lankesterella, Schellackia and Lainsonia) [1,2,3] In the past, these parasites were described mainly using morphological features, and based on their occurrence in certain host species. The blood stages of closely related parasites belonging to several genera are often similar, which resulted in some confusion and still ongoing taxonomic debates about the validity of many species names and their generic position This is true for Hepatozoon, Isospora, and Lankesterella parasites in birds [1,3,4,5]

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