Search Results (54)

Birds are hosts to a diverse assemblage of vector-transmitted haemosporidian parasites. However, the true genetic diversity and many host–parasite interactions are still unknown, particularly in under-represented species groups such as wild doves and pigeons (Columbiformes). In this study, we examined the prevalence and lineage diversity of haemosporidian genera Plasmodium, Leucocytozoon, and Haemoproteus in three species of wild columbids, sampled in Germany. Examinations were performed by applying molecular methods (nested PCR and one-step multiplex PCR) and blood smear examination, and their respective advantages and disadvantages are discussed. In the case of the European Turtle Dove Streptopelia turtur, samples were collected along a west–east gradient throughout Germany, covering migratory birds from the Western and Central-Eastern flyway of this species. Although no infection was detected in the Stock Dove Columba oenas samples, 53% of Turtle Dove and 86% of Common Woodpigeon Columba palumbus harbored a parasite of at least one haemosporidian genus, revealing previously unknown lineage–host interactions. We were not able to demonstrate a correlation between infection status (presence or absence of infection based on PCR results) and parasitemia with condition based on the heterophil to lymphocyte ratio (H/L ratio). Neither lineage occurrence nor prevalence of infection followed any geographically specific patterns. Thus, haemosporidian lineages found in Turtle Doves could not be used as a marker of geographic origin that would allow the tracking of their nonbreeding distribution. Full article

Culicoides biting midges (Diptera: Ceratopogonidae) are important vectors of avian haemosporidian parasites. Understanding their host preferences is crucial for elucidating transmission routes of vector-borne pathogens. In Slovakia, such knowledge is limited, particularly in forested wetlands. This study aimed to identify Culicoides species, their host preferences, and haemosporidian parasites in a wetland ecosystem at the Bird Ringing Station in Drienovec. Midges were collected in 2022 using UV light traps at two sites. In total, 2344 Culicoides individuals of 19 species were collected. Host blood was identified and DNA subsequently extracted from 36 engorged females, revealing feeding on three mammal and five bird species. The most frequently identified host was roe deer (Capreolus capreolus), predominantly fed upon by Culicoides obsoletus (Meigen 1818). Notably, avian haemosporidian DNA was detected for the first time in Slovakia in three Culicoides females. In two Culicoides alazanicus Dzhafarov 1961 individuals, DNA of Haemoproteus asymmetricus (TUPHI01) and Plasmodium matutinum (LINN1) was confirmed, both associated with avian blood from Turdus sp. One Culicoides festivipennis Kieffer 1914 female carried Haemoproteus tartakovskyi (HAWF1) and fed on Coccothraustes coccothraustes. These findings highlight the potential role of local Culicoides species in transmitting avian pathogens and underscore the importance of monitoring their ecology. Full article

Despite numerous studies on haemosporidians in wild birds from Brazil, the presence of other vector-borne agents (VBA) such as Anaplasma spp., Bartonella spp., and Onchocercidae filariids in avian hosts remains largely unknown. The low occurrence of these VBAs might be due to the low sensitivity of traditional molecular techniques. The microfluidic real-time PCR assay, known for its high sensitivity, has emerged as a promising method to detect and study the occurrence and diversity of VBAs in both arthropod vectors and vertebrate hosts. To validate previously and standardize newly designed microfluidic real-time PCR protocols, selected positive avian blood DNA samples for Anaplasma spp., Bartonella spp., haemosporidians, and filariids were used. The molecular occurrence rates for the selected VBAs were 18.2% for Anaplasma spp., 0.36% for Bartonella spp., 6.2% for Plasmodium spp., 4.7% for Haemoproteus spp., and 6.5% for Onchocercidae filariids. The Plasmodium spp. cytB sequence detected in a Volatinia jacarina clustered with Plasmodium tejerai, whereas the Haemoproteus spp. cytB sequence detected in a Columbina squamata clustered with Haemoproteus columbae. While Onchocercidae filariid cox-1 sequences were detected in specimens of Ramphocelus carbo, Turdus amaurocalinus and Synallaxis albilora grouped with Aproctella spp., one sequence detected in R. carbo was ancestral to the clade comprising Splendidofilaria spp. and Eufilaria spp. High-throughput microfluidic real-time PCR assay can be used for screening VBAs in avian hosts from South America, but new primers/probe sets should be designed for VBA genotypes present in Brazil. Full article

Haemosporidian parasites (Apicomplexa, Haemosporida) are diverse obligatory heteroxenous protists, which infect all major groups of terrestrial vertebrates and use dipterous blood-sucking insects as vectors. These pathogens are responsible for various diseases, including malaria, which remains an important human and animal illness. In the wild, haemosporidians are particularly diverse in reptiles and birds in tropical countries, where they are flourishing. Avian haemosporidians have been particularly extensively investigated, especially due to their high prevalence and global distribution, including the countries with cold climates. The general scheme of the life cycle of haemosporidians is known, but the details of development remain insufficiently investigated or even unknown in most of the described parasite species, suggesting the existence of knowledge gaps. This attracts attention to some recent observations, which remain fragmentary but suggest the existence of formerly neglected or underestimated modes of the haemosporidians’ survival in vertebrates. Such findings are worth discussion as they indicate the novel directions in wildlife haemosporidian research. This article overviews some recent findings, which call for broadening of the orthodox views on modes of existence of haemosporidian parasites in avian hosts. Among them are the role of blood merogony in the long-lasting persistence of malaria parasites in birds, the role of gametocytes in the long-lasting survival of Haemoproteus species in vertebrates, the possible reasons of undetectable avian Haemoproteus infections due to peculiarities of exo-erythrocytic development, and the plausible factors driving the narrow vertebrate host specificity of Haemoproteus species. Full article

In this study, for the first time, a systematic review and meta-analysis were conducted to understand the prevalence and genetic diversity of haemosporidian parasites—namely, Plasmodium, Haemoproteus and Leucocytozoon—in avian species in Southeast Asia. Following the PRISMA guidelines, 14,211 studies were retrieved from PubMed, ScienceDirect and Scopus, which contain data relevant to ‘Plasmodium’ or ‘Haemoproteus’ or ‘Leucocytozoon’ and ‘birds’ or ‘chickens’. Of these, 15 articles reporting the prevalence of Plasmodium, Haemoproteus or Leucocytozoon in Southeast Asia were selected for meta-analysis. The pooled prevalence estimates with 95% confidence intervals (CIs) of Plasmodium, Haemoproteus and Leucocytozoon were analyzed using a meta-analysis of their proportions, implemented in R programming. The publication bias was checked using a funnel plot and Egger’s test. Consequently, the pooled prevalences of Plasmodium, Haemoproteus and Leucocytozoon in Southeast Asia were found to be 21% (95% CI: 18–25%), 18% (95% CI: 15–22%) and 34% (95% CI: 30–37%), respectively. The prevalence of Plasmodium in domestic poultry (37.94%) was found significantly higher than in wild birds (6.46%). There was substantial heterogeneity among studies related to Plasmodium (χ² = 171.50, p < 0.0001, I² = 94.84%), Haemoproteus (χ² = 52.20, p < 0.0001, I² = 90.4%) and Leucocytozoon (χ² = 433.90, p < 0.0001, I² = 98.80%). Additionally, this review revealed 23 lineages of Plasmodium, 35 lineages of Haemoproteus and 21 lineages of Leucocytozoon reported from both domestic poultry and wild birds in Southeast Asia. In conclusion, this systematic review suggested that the prevalence of avian haemosporidian parasites in Southeast Asia is high. Particularly, domestic poultry has a high prevalence of Plasmodium, suggesting that monitoring of this parasite should be implemented in the poultry production system. Furthermore, several parasites found in wild birds are undescribed species. Further experimental studies using combined microscopic and molecular techniques might reveal the characteristics of overlooked parasites. Full article

Avian malaria has been a continuous problem in both wild and captive populations of penguins throughout the world. In Japan, where there are over 3000 captive penguins, avian malaria (by Plasmodium spp.) and haemoproteosis (by Haemoproteus spp.) have been sporadically detected throughout the country. However, no comprehensive studies have been carried out, and the national status of infection has been unknown until now. In this study, the prevalence and lineage composition of haemosporidian parasites was investigated in captive penguins throughout Japan for the first time. A total of 1203 penguins from 55 facilities were sampled from January 2010 to December 2019. Parasites were detected by nested PCR and microscopy of blood and tissue samples. The total prevalence was 7.48% for Plasmodium and 1.75% for Haemoproteus, of which some are suggested to have been acquired during the study period. The odds of infection were higher in individuals kept outdoors compared to indoors, re-confirming that exposure to vectors is one of the major factors. Additionally, the odds of death were higher in infected individuals, although differences between parasite lineages were also observed. This study provides an overview of avian malaria in penguins of Japan in the hope of guiding future studies and conservation actions in captivity. Full article

Malaria and other haemosporidian parasites are common in reptiles. During baseline health surveys of sea turtles in Western Australia (WA), haemosporidian parasites were detected in flatback (Natator depressus) and green (Chelonia mydas) turtle erythrocytes during routine blood film examination. 130 blood samples were screened via polymerase chain reaction (PCR), including 105 N. depressus, 20 C. mydas, and 5 olive ridley turtles (Lepidochelys olivacea). A novel Haemocystidium sp. was identified, detected exclusively in foraging turtles and not in nesting turtles. The combined prevalence by microscopic and molecular methods was 16.9% (22/130), primarily affecting immature C. mydas (77.3%; 17/22). Mature N. depressus were also affected (22.7%; 5/22). DNA sequencing of a partial fragment of the mitochondrial cytochrome b (cytb) gene together with phylogenetic analysis identified two different Haemocystidium sp. genotypes, A and B, with genotype A being most prevalent. The phylogenetic analysis showed close genetic relationships to Haemocystidium sp. in freshwater and terrestrial turtles, suggesting a shared evolutionary lineage despite ecological differences. Preliminary analysis indicates that this parasite is incidental, as no association between health and parasite presence or grade was detected. This study provides the first formal detection of haemosporidian parasites in sea turtles, contributing essential baseline data while highlighting their evolutionary significance and host–parasite ecological relationships. Full article

The part of the life cycle concerning the vectors of avian haemosporidians of the genus Haemoproteus remains only partially studied. This work presents the results of capturing and analyzing female Culicoides biting midges for Haemoproteus infection, collected on the Curonian Spit of the Baltic Sea. The midges were collected from April to August 2023 in dry and wet habitats of the Spit using light traps. Each parous female midge was identified to the species level and then its salivary glands were isolated to prepare a thin smear. The preparation was examined under a light microscope for the presence of parasite stages infecting the birds (sporozoites). PCR analysis was also conducted to assess the prevalence of infection in the midges and the genetic diversity of Haemoproteus spp. among vectors on the Curonian Spit. As a result, 995 Culicoides females belonging to 12 species were collected over the course of 4 months. The highest number of midges was recorded in June. The dominant species were Culicoides kibunensis and Culicoides pictipennis. Molecular analysis showed that 2.71% (n = 27) of the examined individuals contained DNA of Haemoproteus spp. Parasites were found in midges of C. pictipennis, C. kibunensis, C. segnis, C. obsoletus, C. punctatus, C. reconditus, C. festivipennis, and C. pallidicornis from May 15 to July 13. The DNA of the identified parasites belonged to six genetic lineages of Haemoproteus—Haemoproteus parabelopolskyi hSYAT02, H. asymmetricus hTUPHI01, H. minutus hTURDUS2, H. spp. hBRAM1, hHAWF6, and hHIICT1. Sporozoites of H. parabelopolskyi hSYAT02 were detected in two individuals of C. pictipennis and one of C. kibunensis. Thus, taking into account the previous results of other studies, we have assumed that these two midge species are competent vectors for Haemoproteus parasites on the Curonian Spit. Full article

Culex pipiens mosquitoes (Diptera: Culicidae) are widespread during warm periods and actively feed on blood while serving as vectors for various human and animal pathogens. Culex mosquitoes overwinter as adults in temperate zones, raising the question of whether hibernating Cx. pipiens can act as pathogen reservoirs. In this study, hibernating mosquitoes and mosquitoes collected during the warm season were tested for the presence of trypanosomatids and avian haemosporidian parasites using PCR. Midgut preparations were made from Cx. pipiens females in order to search for trypanosomatids morphologically. In total, 1037 Cx. pipiens mosquitoes (556 collected during the warm season and 481 overwintering mosquitos) were investigated. The parasite prevalence differed for mosquitoes collected during the warm season and hibernating ones for both Haemosporida (2.9% in warm-season and no infections in overwintering mosquitoes) and Trypanosomatida (1.6% and 0.4%, respectively) parasites. A phylogenetic analysis confirmed that the trypanosomatids found in hibernating mosquitoes were monoxenous and were not parasites of vertebrates. The peak prevalence of Haemosporida parasites was detected in July (4.9%) and August (2.8%), and for Trypanosomatida, it was detected in May (3.5%). The results of the present study show that overwintering Cx. pipiens mosquitoes are questionable reservoirs for avian haemosporidian parasites, but some monoxenous trypanosomatids can be found in overwintering females. Full article

Afrotropical regions have high bird diversity, yet few studies have attempted to unravel the prevalence of avian haemosporidia in conservation areas. The diversity and host specificity of parasites in biodiversity hotspots is crucial to understanding parasite distribution and potential disease emergence. We test the hypothesis that biodiverse regions are associated with highly diverse parasites. By targeting the cytochrome b (Cytb) gene, we molecularly screened 1035 blood samples from 55 bird species for avian haemosporidia infections to determine its prevalence and diversity on sites inside and adjacent to the Kruger National Park. Overall infection prevalence was 28.41%. Haemoproteus, Leucocytozoon, and Plasmodium presented prevalences of 17.39%, 9.24%, and 4.64%, respectively. One hundred distinct parasite lineages were detected, of which 56 were new lineages. Haemoproteus also presented the highest diversity compared to Leucocytozoon and Plasmodium with varying levels of specificity. Haemoproteus lineages were found to be specialists while Plasmodium and Leucocytozoon lineages were generalists. We also found a positive relationship between avian host diversity and parasite diversity, supporting an amplification effect. These findings provide insight data for host–parasite and co-evolutionary relationship models. Full article

Haemosporidians are common blood parasites in wild bird populations, yet their effects on oxidative status remain understudied. Here, we measured the levels of thiobarbituric acid-reactive substances (TBARS) as an indicator of reactive oxygen species (ROS), total antioxidant capacity (TAC) as an indicator of non-enzymatic molecular antioxidants, and TBARS/TAC ratio as an indicator of oxidative status. We also used parasite genus-specific primers and PCR techniques to detect haemosporidians in 117 adults of Rufous-collared Sparrow (Zonotrichia capensis) from four locations in south–central Chile. Mixed-effect models were employed to compare oxidative indicators between infected and uninfected birds. Infected birds showed significantly higher TBARS levels, but no significant differences in TAC, leading to a higher TBARS/TAC ratio, especially in reproductive individuals. This suggests increased oxidative damage in infected birds, irrespective of sex or body condition. A positive relationship between TBARS and TAC was observed in both groups, but the antioxidant response was weaker in infected birds, indicating differential oxidative stress responses based on infection status. Body condition did not differ significantly between infected and uninfected individuals. These results demonstrate that haemosporidian infections impose oxidative costs on birds, potentially compounding the oxidative costs associated with reproduction. Full article

Host range expansions are an important factor for shaping the community of associated symbiotic organisms. Birds, as a highly mobile group of animals, are of particular interest to study with respect to the diversity and the distribution of the organisms using them as hosts during such large-scale movements. The Isabelline wheatear (Oenanthe isabellina) is a species with a main breeding area in Asia, which has expanded west, towards the Balkans, since the middle of the last century. We collected feather mites and blood samples for haemosporidian parasites screening from adult and juvenile Isabelline wheatears from the westernmost edge of the species breeding area in western Bulgaria. The feather mite species Alaudicola rosickyi (Černy, 1963), previously found on other wheatear species, was found for the first time on Isabelline wheatears. One species of avian malaria parasites—Plasmodium relictum (Grassi and Feletti, 1891) (lineage SGS1)—represented the first record of a malaria parasite in this host species in Europe. Increasing the sampling in the South European populations of the species will shed light on blood parasite species diversity and will reveal if other feather mite species have followed their host during its breeding range expansion. Full article

The Asian tiger mosquito (Aedes albopictus) is an invasive mosquito species with a global distribution. This species has populations established in most continents, being considered one of the 100 most dangerous invasive species. Invasions of mosquitoes such as Ae. albopictus could facilitate local transmission of pathogens, impacting the epidemiology of some mosquito-borne diseases. Aedes albopictus is a vector of several pathogens affecting humans, including viruses such as dengue virus, Zika virus and Chikungunya virus, as well as parasites such as Dirofilaria. However, information about its competence for the transmission of parasites affecting wildlife, such as avian malaria parasites, is limited. In this literature review, we aim to explore the current knowledge about the relationships between Ae. albopictus and avian Plasmodium to understand the role of this mosquito species in avian malaria transmission. The prevalence of avian Plasmodium in field-collected Ae. albopictus is generally low, although studies have been conducted in a small proportion of the affected countries. In addition, the competence of Ae. albopictus for the transmission of avian malaria parasites has been only proved for certain Plasmodium morphospecies under laboratory conditions. Therefore, Ae. albopictus may play a minor role in avian Plasmodium transmission in the wild, likely due to its mammal-biased blood-feeding pattern and its reduced competence for the development of different avian Plasmodium. However, further studies considering other avian Plasmodium species and lineages circulating under natural conditions should be carried out to properly assess the vectorial role of Ae. albopictus for the Plasmodium species naturally circulating in its distribution range. Full article

Bird feathers have several functions, including flight, insulation, communication, and camouflage. Since feathers degrade over time, birds need to moult regularly to maintain these functions. However, environmental factors like food scarcity, stress, and parasite infections can affect feather quality and moult speed. This study examined the impact of avian haemosporidian infection and uropygial gland volume, as well as feather quality and feather growth rate in two migratory hirundine species captured in southwestern Spain—the house martin (Delichon urbicum) and sand martin (Riparia riparia). Our findings showed that the prevalence of infection varied among species, with house martins having the highest rates, possibly due to their larger colony size. Moreover, haemosporidian infection had a different impact on each species; infected house martins exhibited lower feather quality than healthy individuals, although this outcome was not observed in sand martins. Furthermore, no effect of infection on feather growth rate was observed in both hirundinids. Additionally, feather growth rate only correlated positively with feather quality in house martins. Finally, no link was observed between uropygial gland volume and feather quality or feather growth rate in any of the species in this study. These findings highlight the effect of haemosporidian infections on the plumage of migratory birds, marking, for the first time, how avian haemosporidian infection is shown to adversely impact feather quality. Even so, further research is needed to explore these relationships more deeply. Full article

In the last decade, over 40% of bird species in Europe have experienced poor and bad conservation status, with more than 30% of bird species in mainland Portugal threatened with extinction. Along with anthropogenic factors, parasites and pathogens such as avian haemosporidians have been suggested to be responsible for these avian population declines. Wildlife rehabilitation centres play an essential role in species conservation and preservation. Moreover, animals admitted for rehabilitation can provide valuable information regarding transmission and pathogenicity of many diseases that affect wild birds that are rarely sampled in nature. However, reports of haemosporidians in captive birds are still limited. Here, we explored the prevalence and genetic diversity of avian haemosporidians in 89 birds from 29 species admitted to rehabilitation centres in Portugal, showing an overall infection prevalence of 30.3%. The prevalence of infection was higher in Strigiformes and in birds admitted to rehabilitation centres due to debilitating diseases. Remarkably, 30% of the infected bird species have not been found to harbour malaria parasites in preceding studies. We detected 15 different haemosporidian lineages infecting a third of bird species sampled. Notably, 2 out of these 15 detected haemosporidian lineages have not been obtained previously in other studies. Furthermore, we also identified nine new host–parasite interactions representing new host records for these haemosporidian parasites. Finally, our results revealed that birds infected with haemosporidians require longer rehabilitation treatments, which increase the economic costs for rehabilitation and may impair their survival prospects. These findings emphasise the importance of integrating haemosporidian infection considerations into rehabilitation protocols, highlighting the challenges posed by these infections in avian conservation and rehabilitation, including economic and logistical demands. Full article