First Record of Leucocytozoon (Haemosporida: Leucocytozoidae) in Amazonia: Evidence for Rarity in Neotropical Lowlands or Lack of Sampling for This Parasite Genus?

Abstract

Birds harbor an astonishing diversity of haemosporidian parasites belonging to the genera Haemoproteus, Leucocytozoon, and Plasmodium. Currently there are more than 250 morphologically described avian haemosporidian species and 2,828 unique lineages found in virtually all avian clades and zoogeographic regions, except for Antarctica. Our report is based on PCR and microscopic screening of 1,302 individual avian samples from Brazil to detect the underrepresented genus Leucocytozoon. This survey primarily focuses on passerine birds collected from Amazonia, the Atlantic Rain Forest, and Pantanal. We also summarize studies conducted in Brazil that report haemosporidian prevalence using both microscopy and molecular tools and present for the first time a record of Leucocytozoon infecting an avian host population in Amazonia. Based on our findings, we suggest that high average temperatures may be constraining both the distribution and diversity of Leucocytozoon in lowland tropical South America.

An inverse latitudinal gradient in infection probability and phylogenetic diversity for Leucocytozoon blood parasites in New World birds

“…Previous studies have shown that climate has little or no influence on the diversity and distributions of two related genera ( Plasmodium and Haemoproteus ) in both Nearctic (Ellis et al, ) and Neotropical birds (Fecchio, Bell, et al, ), whereas temperature explained haemosporidian prevalence (including Leucocytozoon ) in Arctic birds (Oakgrove et al, ). Although Plasmodium prevalence and distribution are constrained by low temperature due to thermal limits on parasite development within mosquito vectors (LaPointe, Goff, & Atkinson, ), Leucocytozoon might be constrained by high temperature (Fecchio et al, ). Experimental infections under laboratory conditions will be necessary to confirm whether high temperature is a limiting factor for Leucocytozoon parasite development within their vectors, which ultimately affects prevalence and distributions among their avian hosts, thus constraining lineage diversity across biogeographical regions.…”

“…Historically, the genus Leucocytozoon has been vastly undersampled, with limited information on prevalence, distribution, diversity, taxonomy and its relationships with avian and vector hosts (Fecchio et al, 2018;Galen, Nunes, Sweet, & Perkins, 2018;Lotta et al, 2016;Lutz et al, 2015;Valkiūnas, 2005). It has been recently suggested that high temperature is an environmental filter for Leucocytozoon that might constrain parasite prevalences and distributions in lowland South America (Fecchio et al, 2018).…”

“…Historically, the genus Leucocytozoon has been vastly undersampled, with limited information on prevalence, distribution, diversity, taxonomy and its relationships with avian and vector hosts (Fecchio et al, 2018;Galen, Nunes, Sweet, & Perkins, 2018;Lotta et al, 2016;Lutz et al, 2015;Valkiūnas, 2005). It has been recently suggested that high temperature is an environmental filter for Leucocytozoon that might constrain parasite prevalences and distributions in lowland South America (Fecchio et al, 2018). This hypothesis was based on the scarcity of Leucocytozoon infections reported in Brazilian lowlands (Fecchio et al, 2018), whereas higher prevalence has been reported in the tropical Andes, especially above 2,000 m (Galen & Witt, 2014;Harrigan et al, 2014;Lotta et al, 2016), where the annual average temperature is lower compared to lowland tropical sites.…”

“…This hypothesis was based on the scarcity of Leucocytozoon infections reported in Brazilian lowlands (Fecchio et al, 2018), whereas higher prevalence has been reported in the tropical Andes, especially above 2,000 m (Galen & Witt, 2014;Harrigan et al, 2014;Lotta et al, 2016), where the annual average temperature is lower compared to lowland tropical sites. Fecchio et al (2018) linked the scarcity of Leucocytozoon infections with warmer temperatures in the tropical lowlands rather than a lack of transmission opportunity, as the vectors for this genus (black flies in the family Simuliidae) are abundant and diverse in lowland regions. Nevertheless, some studies have found strong support for the relationship between prevalence of Leucocytozoon and altitude (Barrow et al, 2019;Galen & Witt, 2014;González et al, 2014;Harrigan et al, 2014;Lotta et al, 2016) or latitude (Merino et al, 2008).…”

“…Using phylogenetic Bayesian hierarchical models, we asked whether patterns of parasite diversity and probability of infection across the New World are driven by site-level (climate, latitude, altitude and landscape) or host species-level predictors (host phylogenetic relationships, diet, height of foraging and sex). We predicted that Leucocytozoon infection probability would be higher in regions with lower temperature (Fecchio et al, 2018;Valkiūnas, 2005). If parasite host shifting decreases continuously with increasing phylogenetic distance between its original host and potential new hosts (Clark & Clegg, 2017;Poulin, Krasnov, & Mouillot, 2011), we would expect similar infection rates among closely related host species.…”