Haemoproteosis lethality in a woodpecker, with molecular and morphological characterization of Haemoproteus velans (Haemosporida, Haemoproteidae).

Tierra C Groff,Gediminas Valkiūnas,Teresa J Lorenz,Ravinder N.M Sehgal,Tatjana Iezhova,Rocio Crespo

doi:10.1016/j.ijppaw.2019.07.007

Abstract

A juvenile White-headed woodpecker (Dryobates albolarvatus) fitted with a radio tag was located dead at approximately 22-days post-fledging in Yakima county in central Washington in July 2015. Postmortem examination revealed an enlarged liver and spleen plus evidence of iron sequestration. Microscopic examination observed young gametocytes within the cytoplasm of erythrocytes, and exo-erythrocytic meronts within the cytoplasm of capillary endothelial cells, hepatocytes, and myocytes, and free in the tissues. These attributes implicated a haemosporidian infection that likely resulted in mortality. Subsequent sampling results of local woodpecker species in the same area during the breeding season in June–July 2016 and May–July 2017 showed other individuals infected with Haemoproteus parasites. Nested Polymerase Chain Reaction (PCR), sequencing, and microscopic analyses for avian haemosporidians revealed infections with Haemoproteus velans (Haemosporida, Haemoproteidae). This parasite was characterized molecularly and morphologically. This is the first report of a haemosporidian infection in a White-headed woodpecker anywhere in its range, and the first reported suspected mortality from haemoproteosis for a woodpecker (Piciformes, Picidae). The use of radio-tagged birds is an asset in wildlife haemosporidian studies because the effect of the pathogen can be monitored in real time. Additionally, this methodology provides opportunities to collect fresh material for microscopic and histological examination from wild birds that have died from natural causes.

Highlights

Prevalent worldwide, avian haemosporidian parasites (Apicomplexa, Haemosporida) belonging to the genera Leucocytozoon, Plasmodium, Haemoproteus, and Fallisia infect a majority of terrestrial avian species (Valkiūnas, 2005)
Haemoproteus velans infection can result in fatalities in woodpeckers, but the frequency of mortality remains unclear
Haemosporidian infections of any kind have not been described as a source of mortality in White-headed woodpeckers in past publications

Summary

Introduction

Avian haemosporidian parasites (Apicomplexa, Haemosporida) belonging to the genera Leucocytozoon, Plasmodium, Haemoproteus, and Fallisia infect a majority of terrestrial avian species (Valkiūnas, 2005). Current sampling techniques favor capturing wild individuals with light (chronic) parasitemia (Valkiūnas, 2005; Mukhin et al, 2016) These birds have already survived the acute stage of infection and are healthy enough to be mobile in the environment, breed, and migrate (Bennett et al, 1993b; Mukhin et al, 2016). Locating wild haemosporidian caused fatalities presents logistical challenges, leading to biased detection of mortality rates (Holmes, 1982; Bennett et al, 1993b; Valkiūnas, 2005). These sampling biases lead to the assumption that avian haemosporidian infections are relatively benign in wild populations (Bennett et al, 1993b)

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