Culicoides (Diptera: Ceratopogonidae) biting midges are a diverse group of insect vectors that transmit pathogens affecting humans, livestock, and wild animals. Among them, Oropouche virus, African Horse sickness virus, and bluetongue virus are the most notable pathogens. However, comparatively little is known about which Culicoides species serve as vectors of wildlife parasites affecting wild birds globally, including the malaria-like parasite of the genus Haemoproteus (Haemosporida: Haemoproteidae) and kinetoplastid Trypanosoma (Trypanosomatida: Trypanosomatidae). Beyond the direct impact of their bites, infections by these parasites negatively affect wild birds from early developmental stages, significantly influencing their ecology and evolution. Here, we present a comprehensive review of the role of Culicoides species in the transmission of these two genera of avian parasites in Europe: Haemoproteus and Trypanosoma. We identify key information and methods used to study Culicoides-bird-parasite interactions, from insect sampling to vector competence assessment. Additionally, we highlight key knowledge gaps and propose future research directions in this area.

• Keywords
• Culicoides, Haemoproteus, Trypanosoma, Avian malaria, Birds, Blood parasites, Vectors,
• MeSH
• Ceratopogonidae * parasitology   physiology   MeSH
• Animals, Wild parasitology   MeSH
• Haemosporida physiology   isolation & purification   MeSH
• Insect Vectors * parasitology   MeSH
• Bird Diseases * transmission   parasitology   epidemiology   MeSH
• Protozoan Infections, Animal * transmission   parasitology   epidemiology   MeSH
• Birds * parasitology   MeSH
• Trypanosoma physiology   isolation & purification   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Geographicals
• Europe epidemiology   MeSH

BACKGROUND: Traditionally, blood meal analysis has been the primary method used to assess feeding patterns of insects. In contrast, parasite detection is commonly applied to monitor parasite circulation and prevalence in vectors, but rarely to study host feeding patterns. Our study aimed to test whether broad-target screening for haemosporidian and trypanosome parasites could complement blood barcoding by revealing additional host associations. We hypothesised that combining both methods would provide a more comprehensive understanding of vector feeding behaviour than either method alone. In addition to evaluating the two methods, we also analysed the vector species composition and their abundance, providing important faunistic and prevalence data that contribute to the broader understanding of local vector-parasite dynamics. METHODS: Mosquitoes and biting midges were trapped over a 5-year period at three localities in Czechia. Blood-fed individuals underwent blood meal barcoding analysis. In parallel, parasite detection was conducted using nested polymerase chain reaction (PCR) and gut dissection techniques. RESULTS: A total of 10,152 mosquitoes were collected, with Culex pipiens (66%) and Aedes vexans (18%) being the predominant species. In addition, 1701 biting midges, primarily Culicoides pictipennis (61%) and C. festivipennis (12%), were captured. Among the collected samples, 281 mosquitoes (3%) and 52 biting midges (3%) were blood-fed. Parasites were detected in 468 mosquito pools (5%, 341 trypanosomes, 127 haemosporidians) and 21 midge pools (1%, 8 trypanosomes, 13 haemosporidians). Blood meal barcoding of engorged Aedes, Anopheles, Culiseta, and Mansonia samples revealed only mammalian hosts; however, parasite detection indicated previous feeding on birds. Culex displayed stronger ornithophily according to parasite detection, although blood meal analysis showed a more opportunistic behaviour, with the detection of avian, mammalian and even amphibian blood. Avian parasites were detected in five Culicoides species (Culicoides alazanicus, C. festivipennis, C. kibunensis, C. nubeculosus and C. pictipennis) while human blood was detected only in C. pictipennis. Overall, four Haemoproteus lineages and 15 Plasmodium lineages were identified, 11 of which were new records for Czechia and 4 were newly described. CONCLUSIONS: Integrating blood meal analysis with parasite detection provides a more comprehensive understanding of insect feeding patterns and vector-host dynamics. Blood meal analysis remains the gold standard for identifying recent host interactions, offering direct and often species-level evidence of feeding events. In addition, parasite detection extends the window of detectability beyond the digestion of host blood and can reveal additional or otherwise-overlooked host associations. Together, these complementary approaches increase the likelihood of detecting interactions with a broader range of hosts, including humans, who might be missed by parasite screening alone.

• Keywords
• T. theileri, Avian trypanosomes, Biting midge, Blood meal, Haemosporidians, Host feeding patterns, Method comparison, Mosquito,
• MeSH
• Ceratopogonidae * parasitology   physiology   MeSH
• Culicidae * parasitology   physiology   MeSH
• Haemosporida isolation & purification   genetics   MeSH
• Insect Vectors * parasitology   physiology   MeSH
• Host-Parasite Interactions MeSH
• Mosquito Vectors * parasitology   physiology   MeSH
• Blood * parasitology   MeSH
• Polymerase Chain Reaction MeSH
• Feeding Behavior * MeSH
• Trypanosoma isolation & purification   genetics   MeSH
• Animals MeSH
• Check Tag
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Czech Republic MeSH

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.

• Keywords
• biting midges, host blood, molecular detection, potential vectors,
• MeSH
• Ceratopogonidae * parasitology   physiology   MeSH
• Haemosporida * isolation & purification   genetics   MeSH
• Insect Vectors * parasitology   MeSH
• Host Specificity * MeSH
• Wetlands MeSH
• Birds parasitology   MeSH
• Animals MeSH
• Check Tag
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Slovakia MeSH

Avian trypanosomes (Trypanosoma, Kinetoplastea) are successful blood parasites occurring worldwide. These parasites are usually non-pathogenic to their avian hosts, thus neglected in studies regarding their life cycles and vectors. Several families of blood-sucking dipteran insects, including mosquitoes, have been identified as vectors of avian trypanosomes. Mosquitoes have been experimentally confirmed as vectors of Trypanosoma culicavium and Trypanosoma thomasbancrofti. In this study, we describe a third species of avian trypanosomes occurring in mosquitoes, designated as Trypanosoma tertium n. sp. This species can be distinguished from related trypanosome species based on morphology and small subunit rRNA gene sequence. Two isolates of T. tertium n. sp. obtained from a mosquito and a bird host were able to infect two subspecies of laboratory Culex pipiens mosquitoes, with infection rates reaching 60% and heavy infections in 90% of positive females. In infected mosquitoes, trypanosomes occurred as long epimastigotes in the midgut and short epimastigotes and rosettes in the hindgut. Putative infectious stages were detected in the diuretic liquid of infected mosquitoes, suggesting, besides transmission through ingestion of the infected vector, a possible transconjunctival infection. Among wild mosquitoes, avian trypanosomes were detected exclusively in Cx. pipiens with 3.3% total prevalence, while T. tertium n. sp. prevalence was only 0.08% among 1128 dissected Cx. pipiens individuals. In birds, T. tertium n. sp. was detected in 8 species within which the prevalence was 1.3% (686 birds), while it was 0.3% in total (3084 birds). We discuss the relationship of the newly described T. tertium n. sp. with other mosquito-transmitted trypanosomes.

• Keywords
• Culex, avian blood parasite, monoxenous Kinetoplastea, morphology, phylogeny, transmission, vector,
• MeSH
• Culex * parasitology   MeSH
• Phylogeny MeSH
• Mosquito Vectors * parasitology   MeSH
• Bird Diseases * parasitology   epidemiology   transmission   MeSH
• Prevalence MeSH
• Trypanosoma * genetics   isolation & purification   classification   growth & development   MeSH
• Trypanosomiasis * veterinary   parasitology   epidemiology   transmission   MeSH
• Animals MeSH
• Check Tag
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

Uganda's diverse small mammalian fauna thrives due to its rich habitat diversity, which hosts a wide range of blood parasites, including trypanosomes, particularly the subgenus Herpetosoma typical for rodent hosts. We screened a total of 711 small mammals from various habitats for trypanosomes, with 253 microscopically examined blood smears and 458 tissue samples tested by nested PCR of the 18S rRNA gene. Of 51 rodent and 12 shrew species tested, microscopic screening reaches 7% overall prevalence (with four rodent species positive out of 15 and none of the shrew species out of four), while nested PCR indicated a prevalence of 13% (17 rodent and five shrew species positive out of 49 and 10, respectively). We identified 27 genotypes representing 11 trypanosome species, of which the majority (24 genotypes/9 species) belong to the Herpetosoma subgenus. Among these, we detected 15 new genotypes and two putative new species, labeled AF24 (found in Lophuromys woosnami) and AF25 (in Graphiurus murinus). Our finding of three new genotypes of the previously detected species AF01 belonging to the subgenus Ornithotrypanum in two Grammomys species and Oenomys hypoxanthus clearly indicates the consistent occurrence of this avian trypanosome in African small mammals. Additionally, in Aethomys hindei, we detected the putative new species of the subgenus Aneza. Within the T. lewisi subclade, we detected eleven genotypes, including six new; however, only the genotype AF05b from Mus and Rattus represents the invasive T. lewisi. Our study has improved our understanding of trypanosome diversity in African small mammals. The detection of T. lewisi in native small mammals expands the range of host species and highlighting the need for a broader approach to the epidemiology of T. lewisi.

• Keywords
• Aneza, Herpetosoma, Muridae, Ornithotrypanum, Soricidae,
• MeSH
• Phylogeny MeSH
• Rats MeSH
• Murinae parasitology   MeSH
• Shrews MeSH
• Trypanosoma lewisi * genetics   MeSH
• Trypanosoma * genetics   MeSH
• Trypanosomiasis * epidemiology   veterinary   parasitology   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Uganda epidemiology   MeSH

BACKGROUND: A high prevalence of parasites may result from life-long persistence of infection or from high reinfection rates. We have studied blood parasites in a breeding population of the accipitrid raptor, Eurasian sparrowhawk (Accipiter nisus), to determine parasite diversity and turnover. METHODS: During this 7-year study, 210 adult Eurasian sparrowhawks breeding in the city of Prague were checked for parasites using several diagnostic methods. RESULTS: In both female and male raptors, parasites of the genus Leucocytozoon were the most prevalent (92% and 85%, respectively) followed in decreasing order of prevalence by those of genus Trypanosoma (74% and 68%, respectively) and genus Haemoproteus (46% and 16%, respectively). The prevalence of all parasites increased with age in both sexes, with the females at each respective age having the higher prevalence. There was a positive association between Haemoproteus and Leucocytozoon infections. Persistence at the individual level was higher than incidence for Trypanosoma and Haemoproteus. In the case of Leucocytozoon and Trypanosoma, most individuals probably become infected in their first year of life or even before dispersal from the nest. The detected parasites belonged to Trypanosoma avium sensu stricto, Leucocytozoon sp. (haplotypes ACNI1 and ACNI3) and Leucocytozoon mathisi (haplotype ACNI4) and two new lineages of the Haemoproteus elani complex (ACCNIS6 and ACCNIS7). Detailed analysis of parasite lineages in individuals that were repeatedly sampled revealed lineage turnover that would otherwise remain hidden. Phylogenetic analysis revealed that the detected Haemoproteus belongs to a phylogenetically distant group whose taxonomic position requires further analysis. CONCLUSIONS: All three genera of blood parasites persist in infected individuals, thus enabling sustainability of vector transmission cycles. Prevalence increases with age; however, there is a high turnover of Leucocytozoon lineages. No clear evidence of parasite-induced mortality was found, and most of the individuals were infected early in life, particularly in the case of Leucocytozoon.

• Keywords
• Avian blood parasite, Birds of prey, Haemosporida, Parasite persistence, Raptor, Trypanosoma avium, Trypanosoma bennetti, Trypanosoma corvi,
• MeSH
• Phylogeny MeSH
• Haemosporida * genetics   MeSH
• Incidence MeSH
• Hawks * parasitology   MeSH
• Bird Diseases * parasitology   MeSH
• Prevalence MeSH
• Protozoan Infections, Animal * parasitology   MeSH
• Trypanosoma * genetics   MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

Wild birds are hosts of Culicoides from as early on as the nesting stage when constrained to their nests. However, the environmental factors which determine the abundance and composition of Culicoides species within each bird nest are still understudied. We sampled Culicoides from Eurasian blue tit (Cyanistes caeruleus) nests found in 2 types of forests located in southern Spain. Firstly, we monitored the abundance of Culicoides species in bird nests from a dry Pyrenean oak deciduous forest and a humid mixed forest comprising Pyrenean and Holm oaks throughout 2 consecutive years. During the 3rd year, we performed a cross-fostering experiment between synchronous nests to differentiate the role of rearing environment conditions from that of the genetically determined or maternally transmitted cues released by nestlings from each forest. We found 147 female Culicoides from 5 different species in the birds' nests. The abundance of Culicoides was higher in the dry forest than in the humid forest. Culicoides abundance, species richness and prevalence were greater when the nestlings were hatched later in the season. The same pattern was observed in the cross-fostering experiment, but we did not find evidence that nestling's features determined by the forest of origin had any effect on the Culicoides collected. These results support the notion that habitat type has a strong influence on the Culicoides affecting birds in their nests, while some life history traits of birds, such as the timing of reproduction, also influence Culicoides abundance and species composition.

• Keywords
• Avian malaria, Haemoproteus, avian nests, biting midges, blood-feeding insects, host selection, vectors,
• MeSH
• Ceratopogonidae * MeSH
• Forests MeSH
• Seasons MeSH
• Reproduction MeSH
• Songbirds * MeSH
• Animals MeSH
• Check Tag
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Louse flies (Hippoboscidae) are permanent ectoparasites of birds and mammals. They have a cosmopolitan distribution with more than 200 described species. The aim of this study was to reveal host-vector-parasite associations between louse flies, birds, and trypanosomes. A total of 567 louse fly specimens belonging to 7 species were collected from birds at several localities in Czechia, including the rare species Ornithophila metallica and Ornithoica turdi. There was a significant difference in the occurrence of Ornithomya avicularia and Ornithomya fringillina on bird hosts according to their migratory status, O. fringillina being found more frequently on long-distance migrants. Trypanosomes were found in four species, namely, Ornithomya avicularia, O. fringillina, O. biloba, and Ornithoica turdi; the later three species are identified in this paper as natural trypanosome vectors for the first time. The prevalence of trypanosomes ranged between 5 and 19%, the highest being in O. biloba and the lowest being in O. fringillina. Phylogenetic analysis of the SSU rRNA gene revealed that a vast majority of trypanosomes from hippoboscids belong to the avian T. corvi/culicavium group B. Four new lineages were revealed in group B, with louse flies being probable vectors for some of these trypanosome lineages. We also confirmed the transcontinental distribution of several trypanosome lineages. Our results show that hippoboscids of several genera are probable vectors of avian trypanosomes.

• Keywords
• Hippoboscidae, Ornithoica, Ornithomya, Ornithophila, Trypanosoma, avian parasite, host specificity, transmission,
• Publication type
• Journal Article MeSH

Avian trypanosomes are cosmopolitan and common protozoan parasites of birds; nevertheless, knowledge of their life cycles and vectors remains incomplete. Mosquitoes have been confirmed as vectors of Trypanosoma culicavium and suggested as vectors of T. thomasbancrofti; however, transmission has been experimentally confirmed only for the former species. This study aims to confirm the experimental transmission of T. thomasbancrofti to birds and its localization in vectors. Culex pipiens were fed on blood using four strains of T. thomasbancrofti, isolated from vectors and avian hosts; all strains established infections, and three of them were able to develop high infection rates in mosquitoes. The infection rate of the culicine isolates was 5-28% for CUL15 and 48-81% for CUL98, 67-92% for isolate OF19 from hippoboscid fly, while the avian isolate PAS343 ranged between 48% and 92%, and heavy infections were detected in 90% of positive females. Contrary to T. culicavium, trypanosomes were localized in the hindgut, where they formed rosettes with the occurrence of free epimastigotes in the hindgut and midgut during late infections. Parasites occurred in urine droplets produced during mosquito prediuresis. Transmission to birds was achieved by the ingestion of mosquito guts containing trypanosomes and via the conjunctiva. Bird infection was proven by blood cultivation and xenodiagnosis; mature infections were present in the dissected guts of 24-26% of mosquitoes fed on infected birds. The prevalence of T. thomasbancrofti in vectors in nature and in avian populations is discussed in this paper. This study confirms the vectorial capacity of culicine mosquitoes for T. thomasbancrofti, a trypanosome related to T. avium, and suggests that prediuresis might be an effective mode of trypanosome transmission.

• Keywords
• Culex, Trypanosoma thomasbancrofti, avian parasite, life cycle, mosquito, prediuresis, transmission,
• Publication type
• Journal Article MeSH

Trypanosomatid flagellates have not been studied in Austria in any detail. In this study, specific nested PCR, targeted on the ribosomal small subunit, was used to determine the occurrence and diversity of trypanosomatids in wild-caught mosquitoes sampled across Eastern Austria in the years 2014-2015. We collected a total of 29,975 mosquitoes of 19 species divided in 1680 pools. Of these, 298 (17.7%), representing 12 different mosquito species, were positive for trypanosomatid DNA. In total, seven trypanosomatid spp. were identified (three Trypanosoma, three Crithidia and one Herpetomonas species), with the highest parasite species diversity found in the mosquito host Coquillettidia richiardii. The most frequent parasite species belonged to the mammalian Trypanosoma theileri/cervi species complex (found in 105 pools; 6.3%). The avian species T. culicavium (found in 69 pools; 4.1%) was only detected in mosquitoes of the genus Culex, which corresponds to their preference for avian hosts. Monoxenous trypanosomatids of the genus Crithidia and Herpetomonas were found in 20 (1.3%) mosquito pools. One third (n = 98) of the trypanosomatid positive mosquito pools carried more than one parasite species. This is the first large scale study of trypanosomatid parasites in Austrian mosquitoes and our results are valuable in providing an overview of the diversity of these parasites in Austria.

• MeSH
• Biodiversity MeSH
• Culicidae parasitology   MeSH
• Phylogeny MeSH
• DNA, Protozoan MeSH
• DNA, Ribosomal MeSH
• Sequence Analysis, DNA MeSH
• Trypanosoma classification   genetics   MeSH
• Trypanosomiasis parasitology   transmission   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Austria MeSH
• Names of Substances
• DNA, Protozoan MeSH
• DNA, Ribosomal MeSH