Prevalence Of Avian Haemosporidian Parasites Research Articles

Haemosporidian parasite infections of Malagasy Philepittidae and Nectariniidae are driven by phylogeny rather than ecology.

The nectarivorous common sunbird asity (Neodrepanis coruscans) is phylogenetically closely related to the frugivorous velvet asity (Philepitta castanea), yet it shares similar habitat and foraging behaviour as the Malagasy sunbirds (Cinnyris spp.). As ecological factors have been shown to influence blood parasite prevalence, it should be tested whether parasite abundance, prevalence and diversity of N. coruscans are more similar to the sunbirds than to its relative. Therefore, blood samples (n = 156) and smears (n = 60) were tested for different blood parasites (Haemosporida, trypanosomes, filarioid nematodes) using molecular and microscopic methods. High prevalence of haemosporidian parasites was observed in all bird taxa, with rates ranging from 23% in N. coruscans to 84.6% in C. notatus. The Malagasy Cinnyris spp. exhibited a high occurrence of mixed haemosporidian infections (>76%) with various specialized lineages. Within the Philepittidae family, no Haemoproteus infection was detected and just a few cases of mixed infections. Nectariniidae species predominantly had specialized haemosporidian lineages, while Philepittidae had infections mainly caused by generalist lineages. These findings emphasize the diverse range of blood parasites in Nectariniidae, while additionally highlighting the high diversity of trypanosomes and filarioid nematodes in Philepittidae. Additionally, several newly discovered haemosporidian lineages, Trypanosoma isolates and filarioid nematode isolates were identified. Notably, Philepittidae exhibited a lower prevalence of avian haemosporidian parasites compared to Nectariniidae, possibly due to potential resistance mechanisms. Despite N. coruscans sharing similar habitat and behavioural ecology with both Cinnyris spp., it closely resembles its relative, P. castanea, in all aspects of haemosporidian parasitism.

Host foraging behavior and nest type influence prevalence of avian haemosporidian parasites in the Pantanal.

Avian haemosporidians from the genera Plasmodium and Haemoproteus are vector transmitted parasites. A growing body of evidence suggests that variation in their prevalence within avian communities is correlated with a variety of avian ecological traits. Here, we examine the relationship between infection probability and diversity of haemosporidian lineages and avian host ecological traits (average body mass, foraging stratum, migratory behavior, and nest type). We used molecular methods to detect haemosporidian parasites in blood samples from 642 individual birds of 149 species surveyed at four localities in the Brazilian Pantanal. Based on cytochrome b sequences, we recovered 28 lineages of Plasmodium and 17 of Haemoproteus from 31 infected avian species. Variation in lineage diversity among bird species was not explained by avian ecological traits. Prevalence was heterogenous across avian hosts. Bird species that forage near the ground were less likely to be infected by Haemoproteus, whereas birds that build open cup nests were more likely infected by Haemoproteus. Furthermore, birds foraging in multiple strata were more likely to be infected by Plasmodium. Two other ecological traits, often related to host resistance (body mass and migratory behavior), did not predict infection probability among birds sampled in the Pantanal. Our results suggest that avian host traits are less important determinants of haemosporidian diversity in Pantanal than inother regions, but reinforces that host attributes, related to vector exposure, are to some extent important in modulating infection probability within an avian host assemblage.

Prevalence of Avian Haemosporidian Parasites in Village Chickens (Gallus gallus domesticus) from Kwami, Gombe State, Nigeria

This study was carried out to determine the prevalence of avian haemosporidian parasites in village chickens in Kwami, Gombe State, Nigeria using microscopy and the associated risk factors using structured questionnaires. To achieve this goal, blood samples were collected from 346 apparently healthy village chickens in Kwami of Gombe State, and a total of 45 farmers were interviewed using structured questionnaires. Microscopy revealed an overall prevalence of 20.8% (72/346) for haemosporidian parasites comprising of Plasmodium spp. with 41 (11.8%; 95% CI = 8.9 – 15.7) and Haemoproteus spp. 23 (6.6%; 95% CI = 4.5 – 9.8) as single infection and mixed infection of Plasmodium + Haemoproteus spp. having 8 (2.3%; 95% CI = 1.2 – 4.5). Prevalence of avian haemosporidian parasites was significantly higher in male (13.9%) compared to hens (6.9%), as well as in adults (14.50%) compared to growers (6.4%). The prevalence was also found to be higher in the rainy season (15.6%) compared to the dry (5.2%) seasons of the study period. Questionnaire survey on attitude and practice of the village chicken farmers in the study area has shown that village chicken are raised under the extensive management system and are reared with other village poultry species on free range. Inadequate biosecurity, poor management and husbandry systems constituted the predisposing risk factors associated with haemoparasite infections in this study.
 Key words: Haemosporidian parasites; Avian malaria, Microscopy, Scavenging Chickens; Kwami, Gombe State

Sex and nest type influence avian blood parasite prevalence in a high-elevation bird community

BackgroundThe prevalence of avian haemosporidian parasites and the factors influencing infection in the Colorado Rocky Mountains are largely unknown. With climate change expected to promote the expansion of vector and avian blood parasite distributions, baseline knowledge and continued monitoring of the prevalence and diversity of these parasites is needed.MethodsUsing an occupancy modeling framework, we conducted a survey of haemosporidian parasite species infecting an avian community in the Colorado Rocky Mountains in order to estimate the prevalence and diversity of blood parasites and to investigate species-level and individual-level characteristics that may influence infection.ResultsWe estimated the prevalence and diversity of avian Haemosporidia across 24 bird species, detecting 39 parasite haplotypes. We found that open-cup nesters have higher Haemoproteus prevalence than cavity or ground nesters. Additionally, we found that male Ruby-crowned Kinglets, White-crowned Sparrows, and Wilson’s Warblers have higher Haemoproteus prevalence compared to other host species. Plasmodium prevalence was relatively low (5%), consistent with the idea that competent vectors may be rare at high altitudes.ConclusionsOur study presents baseline knowledge of haemosporidian parasite presence, prevalence, and diversity among avian species in the Colorado Rocky Mountains and adds to our knowledge of host–parasite relationships of blood parasites and their avian hosts.Graphical

Mining increases the prevalence of avian haemosporidian parasites in Northeast Amazonia.

Studies contrasting parasite prevalence and host-parasite community structure between pristine and disturbed environments will improve our understanding of how deforestation affects disease transmission and parasite extinction. To determine how infection rates of a common and diverse group of avian blood parasites (Plasmodium and Haemoproteus) respond to changes in avian host composition after mining, we surveyed 25 bird communities from pristine forests (two forest types: plateau and hillside) and reforested sites in Northeast Amazonia. Infection rates and both parasite and avian host community structure exhibited considerable variation across the deforestation gradient. In opposition to the emerging pattern of lower avian haemosporidian prevalence in disturbed tropical forests in Africa, we show that secondary forests had higher haemosporidian prevalence in one of the largest mining areas of Amazonia. The dissimilarity displayed by bird communities may explain, in part, the higher prevalence of Haemoproteus in reforested areas owing to the tolerance of some bird species to open-canopy forest habitat. On the other hand, deforestation may cause local extinction of Plasmodium parasites due to the loss of their avian hosts that depend on closed-canopy primary forest habitats. Our results demonstrate that forest loss induced by anthropogenic changes can affect a host-parasite system and disturb both parasite transmission and diversity.

Avian Haemosporidian Parasites in Domesticated Rock Doves ( Columba livia domestica ) in Gombe State, Nigeria

Avian haemosporidian infections are widespread and can result in the decline of populations or extinction of birds’ species. This study aimed to determine the prevalence of avian haemosporidian parasites in 570 rock doves sampled from household and live birds markets from Gombe State, Nigeria. Blood samples were microscopically examined for the presence of haemoparasites, and the overall prevalence of avian haemosporidiosis was 41.8%. The prevalence of haemosporidian was significantly higher (P <0.0001; χ2 = 16.665) in doves from live birds’ markets (25.8%) compared to households (25.8%). Prevalence was also higher (P = 0.2027; χ2 = 1.623) in female (22.3%) compared to male (19.5%) doves. Out of the 238 infected doves, 82 (14.4%) were infected with Haemoproteus , 58 (10.2%) with Plasmodium and 40 (7.0%) with Leucocytozoon species. 25 doves (4.4%) had mixed infection with Haemoproteus + Plasmodium species, 21 (3.7%) had mixed Leucocytozoon species + Plasmodium species infections while 12 (3.7%) had mixed Haemoproteus + Plasmodium + Leucocytozoon species infections. Prevalence of all avian haemosporidian species were higher (P > 0.05) in doves sampled from live birds’ markets compared to those from households, and all avian haemosporidian species except Leucocytozoon species were higher (P > 0.05) in female than in male doves. It is recommended that awareness campaign to educate the poultry farmers and sellers on how to improve management practices is necessary so as to prevent widespread transmission of the haemosporidian parasites amongst domesticated birds.

Effect of deforestation on prevalence of avian haemosporidian parasites and mosquito abundance in a tropical rainforest of Cameroon

Habitat change caused by deforestation can modify the interactions of many biotic and abiotic factors, and in turn influence patterns of diseases in wild birds. Whether deforestation directly or indirectly affects the prevalence of avian haemosporidian parasites through their hosts and/or vectors is still not well understood. We sampled understory bird communities (insectivorous, frugivorous, granivorous and nectarivorous birds) and mosquitoes in three habitats showing a gradient of deforestation (pristine forest, fragmented forest, and young palm oil plantation), to assess the effects of habitat changes on avian haemosporidian (Plasmodium and Haemoproteus) prevalence and its relationship to bird feeding guilds and mosquito abundance. Blood samples of 845 individual birds belonging to 85 species and 27 families were collected in the three habitat types and screened using microscopy and PCR. Plasmodium infections were detected in 136 individuals (16.09%) and varied significantly among habitat types while Haemoproteus infections were detected in 98 individuals (11.60%) and did not vary significantly among habitat types. However, the prevalence of Plasmodium and Haemoproteus in bird feeding groups varied significantly among habitats. Nectarivorous and granivorous birds had the highest Plasmodium and Haemoproteus prevalence, respectively. The abundance of mosquitoes varied significantly among habitat types and the prevalence of Plasmodium significantly and positively correlated with mosquito abundance in fragmented forest. This study highlights the importance of host and mosquito determinants in the transmission dynamics of avian Plasmodium and Haemoproteus infections following habitat changes. Selective logging favored an increase in the prevalence of Plasmodium in insectivores, the prevalence of Haemoproteus in nectarivores and the abundance of female mosquitoes while, the establishment of the palm oil plantation favored an increase in the prevalence of Plasmodium in granivores and Haemoproteus in nectarivores. Species feeding behavior is also an important determinant to consider for a better understanding of patterns of parasite infections in a changing environment.

The prevalence of avian haemosporidian parasites in an invasive bird is lower in urban than in non‐urban environments

Urbanization affects the ecology of wildlife diseases and although it has been suggested that there are lower risks of infection in urban areas, there have been no experiments to support this conclusion. We assessed haemosporidian prevalence and intensity in House Sparrows Passer domesticus using field and experimental data under contrasting conditions (i.e. urban vs. non‐urban). For experimental data, we kept 32 male House Sparrows in captivity as a proxy of stress, and for field data we sampled 49 House Sparrows (17 females). We made use of microscopy to determine the relative intensity and used the polymerase chain reaction to estimate infection prevalence. We obtained total leucocyte counts, leucocyte differentials, heterophil/lymphocyte ratio (H/L) as a measure of stress, and the Polychromatic Index as a measure of physiological condition (erythropoiesis). We identified a total of 10 haemosporidian lineages. For field samples (both males and females), we found a significantly higher prevalence of infection in non‐urban House Sparrows than in urban ones. Under experimental conditions, non‐urban House Sparrows showed a higher prevalence than urban ones both before and after captivity, with a significant increase in parasite intensity. The number of infected birds increased after captivity for both urban (~ 32%) and non‐urban House Sparrows (~ 19%), indicating either a recrudescence of chronic and relapses of latent infections or the appearance of infections that had been acquired earlier. The H/L ratio was significantly higher for non‐urban than for urban male House Sparrows before captivity. No difference in H/L was found for urban House Sparrows before and after captivity, indicating tolerance to city stressors. Our results showed a significant decrease in H/L for non‐urban birds after captivity, suggesting higher stress in the non‐urban agricultural environment. Haemosporidian infections were not associated with the H/L ratio. Our study provides evidence that highly urbanized areas within cities represent lower haemosporidian infection risks than do non‐urban areas for House Sparrows.

Habitat modification and seasonality influence avian haemosporidian parasite distributions in southeastern Brazil.

Habitat modification may change vertebrate and vector-borne disease distributions. However, natural forest regeneration through secondary succession may mitigate these effects. Here we tested the hypothesis that secondary succession influences the distribution of birds and their haemosporidian parasites (genera Plasmodium and Haemoproteus) in a seasonally dry tropical forest, a globally threatened ecosystem, in Brazil. Moreover, we assessed seasonal fluctuations in parasite prevalence and distribution. We sampled birds in four different successional stages at the peak and end of the rainy season, as well as in the middle and at the end of the dry season. A non-metric multidimensional scaling analysis revealed that bird communities in the pasture (i.e., highly modified) areas were different from those in the early, intermediate, and late successional areas (secondary forests). Among 461 individual birds, haemosporidian prevalence was higher in pasture areas than in the more advanced successional stages, but parasite communities were homogeneous across these areas. Parasite prevalence was higher in pasture-specialists birds (resilient species) than in forest-specialists species, suggesting that pasture-specialists may increase infection risk for co-occurring hosts. We found an increase in prevalence between the middle and end of the dry season, a period associated with the beginning of the breeding season (early spring) in southeastern Brazil. We also found effects of seasonality in the relative prevalence of specific parasite lineages. Our results show that natural forest recovery through secondary succession in SDTFs is associated with compositional differences in avian communities, and that advanced successional stages are associated with lower prevalence of avian haemosporidian parasites.

Prevalence of avian haemosporidian parasites is positively related to the abundance of host species at multiple sites within a region.

Parasite prevalence is thought to be positively related to host population density owing to enhanced contagion. However, the relationship between prevalence and local abundance of multiple host species is underexplored. We surveyed birds and their haemosporidian parasites (genera Plasmodium and Haemoproteus) at multiple sites across eastern North America to test whether the prevalence of these parasites in a host species at a particular site is related to that host's local abundance. Prevalence was positively related to host abundance within most sites, although the effect was stronger and more consistent for Plasmodium than for Haemoproteus. In contrast, prevalence was not related to variation in the abundance of most individual host species among sites across the region. These results suggest that parasite prevalence partly reflects the relative abundances of host species in local assemblages. However, three nonnative host species had low prevalence despite being relatively abundant at one site, as predicted by the enemy release hypothesis.

North-African house martins endure greater haemosporidian infection than their European counterparts

Afro-Palearctic migrant species are exposed to parasites at both breeding and over-wintering grounds. The house martin Delichon urbicum is one such migratory species facing high instances of blood parasite infection. In an attempt to determine whether breeding European house martins harbour similar blood parasite communities to populations breeding in North Africa, birds were sampled at their breeding grounds in Switzerland and Algeria. Moreover, haemosporidian prevalence and parasite communities were compared to published data sets on Spanish and Dutch breeding populations. This study furthermore wanted to establish whether co-infection with multiple genera or lineages of parasites had negative effects on host body condition. Breeding house martins caught in Algeria showed a higher prevalence of avian haemosporidian parasites than did European populations. Swiss house martins showed a prevalence comparable to that of Spanish and Dutch populations. There were slight differences in the haemosporidian community between European and North-African populations in terms of composition and abundance of each lineage. Similar to the Dutch house martins, but in contrast to the Spanish population, infection status and number of genera of parasites infecting single hosts did not inFLuence Swiss house martin body condition.

Prevalence of avian haemosporidian parasites and their host fidelity in the central Philippine islands

We examined the prevalence and host fidelity of avian haemosporidian parasites belonging to the genera Haemoproteus, Leucocytozoon and Plasmodium in the central Philippine islands by sampling 23 bird families (42 species). Using species-specific PCR assays of the mitochondrial cytochrome b gene (471base pairs, bp), we detected infections in 91 of the 215 screened individuals (42%). We also discriminated between single and multiple infections. Thirty-one infected individuals harbored a single Haemoproteus lineage (14%), 18 a single Leucocytozoon lineage (8%) and 12 a single Plasmodium lineage (6%). Of the 215 screened birds, 30 (14%) presented different types of multiple infections. Intrageneric mixed infections were generally more common (18 Haemoproteus/Haemoproteus, 3 Leucocytozoon/Leucocytozoon, and 1 Plasmodium/Plasmodium) than intergeneric mixed infections (7 Haemoproteus/Leucocytozoon and 1 Haemoproteus/Leucocytozoon/Plasmodium). We recovered 81 unique haemosporidian mitochondrial haplotypes. These clustered in three strongly supported monophyletic clades that correspond to the three haemosporidian genera. Related lineages of Haemoproteus and Leucocytozoon were more likely to derive from the same host family than predicted by chance; however, this was not the case for Plasmodium. These results indicate that switches between host families are more likely to occur in Plasmodium. We conclude that Haemoproteus has undergone a recent diversification across well-supported host-family specific clades, while Leucocytozoon shows a longer association with its host(s). This study supports previous evidence of a higher prevalence and stronger host-family specificity of Haemoproteus and Leucocytozoon compared to Plasmodium.