Distribution of the avian hematozoa of North America

Abstract

The literature pertaining to the prevalence of avian hematozoa in North America, north of Mexico, together with unpublished records from the files of the International Reference Centre for Avian Malaria Parasites, have been collated and analyzed with respect to the distribution of parasite genera by region, host family, and vertical stratification of nesting sites. The blood parasites of 57 026 birds of 388 species (representing 55 families) breeding in North America are the basis of this analysis. A total of 21 048 (36.9%) birds harbored one or more species of Haemoproteus (19.5%), Leucocytozoon (17.7%), Trypanosoma (3.9%), Plasmodium (3.8%), microfilariae (3.1%), and Haemogregarina/Lankesterella (0.6%). The continent was arbitrarily divided into seven regions along a topographic basis. Overall hematozoan prevalence varied markedly from region to region, as did the relative frequencies of the different genera. Overall hematozoan prevalence also varied markedly from avian family to family, as did the relative frequencies of the different genera. Nine families had prevalences of 50% or more, while 16 families had prevalences of 5% or less; sea- and shore-birds were nearly hematozoan-free. Prevalence of blood parasites is correlated with the vertical stratification of nesting sites when considered on a localized geographic basis but no correlation exists when the results are pooled from the continent.

Blood parasites in some birds from eastern plains of Colombia

“…Even though the Neotropical region possesses the most diverse and richest avifauna of the world, this study indicated a low prevalence of blood parasites (15.9%), but represented a similar value to that recorded elsewhere in Central and South America (White et al 1978: it is far lower than that recorded for North America (Greiner et al 1975). Furthermore, the low number of double infections (4 individuals) found in this study, agrees with other reports from the Neotropics (Bennett & Sousa 1980).…”

“…The families with the highest prevalence in this study were essentially the same as those in other studies in the Neotropics (White et al 1978), and the Neartic (Greiner et al 1975). It would appear that some aspect or habit of these birds enhances parasitism by haematozoans.…”

“…Fifty birds (15.9%) were infected with parasites of one or more genera of haematozoa (Table I). This is higher than the 10.5% prevalence reported by White et al (1978) for the Neotropical region, but clearly lower than the 36.9% recorded for North America (Greiner et al 1975). The 75 species of birds examined included 8 species that were examined for blood-parasites for the first time; 15 new host-parasites records were established from this sample ( Table I).…”

Paucity of Hematozoa in Colombian Birds

“…The Leucocytozoon sp. infection could have been acquired on the Nearctic breeding grounds where the overall prevalence of leucocytozoids exceeds 40% in the Swainson's thrush (Greiner et al, 1975 Haemoproteus sp. infection was recorded in the Magdalena valley (one bird infected, nϭ1) and eastern slope of the Andes (nϭ1), Plasmodium sp.…”

“…The low overall prevalence of hematozoa in Colombia is typical for the Neotropics where the prevalence of blood parasites (approximately 10%) is significantly less than that in any other zoogeographical region (Greiner et al, 1975;White et al, 1978;Valkiū nas, 1997). Species of Haemoproteus, Plasmodium, Leucocytozoon, and Trypanosoma have been found in resident indigenous species of birds in the Neotropics (White et al, 1978;Sousa and Herman, 1982;Young et al, 1993;Valkiū nas, 1997) and thus are transmitted there.…”