Nejvíce citovaný článek - PubMed ID 34683422
Complete Life Cycle of Trypanosoma thomasbancrofti, an Avian Trypanosome Transmitted by Culicine Mosquitoes
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.
- Klíčová slova
- T. theileri, Avian trypanosomes, Biting midge, Blood meal, Haemosporidians, Host feeding patterns, Method comparison, Mosquito,
- MeSH
- Ceratopogonidae * parazitologie fyziologie MeSH
- Culicidae * parazitologie fyziologie MeSH
- Haemosporida izolace a purifikace genetika MeSH
- hmyz - vektory * parazitologie fyziologie MeSH
- interakce hostitele a parazita MeSH
- komáří přenašeči * parazitologie fyziologie MeSH
- krev * parazitologie MeSH
- polymerázová řetězová reakce MeSH
- stravovací zvyklosti * MeSH
- Trypanosoma izolace a purifikace genetika MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika 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.
- Klíčová slova
- Culex, avian blood parasite, monoxenous Kinetoplastea, morphology, phylogeny, transmission, vector,
- MeSH
- Culex * parazitologie MeSH
- fylogeneze MeSH
- komáří přenašeči * parazitologie MeSH
- nemoci ptáků * parazitologie epidemiologie přenos MeSH
- prevalence MeSH
- Trypanosoma * genetika izolace a purifikace klasifikace růst a vývoj MeSH
- trypanozomiáza * veterinární parazitologie epidemiologie přenos MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Parasitic protozoa such as Lankesterella and Isospora are common in avian hosts, particularly in passerines. Despite their high prevalence, the diversity of these parasites within avian populations remains poorly understood. This study aimed to assess the diversity of Lankesterella and Isospora in passerine birds, using the SSU rRNA gene to characterize and compare the genetic variation in both parasites across multiple avian host species. For Isospora, the extraintestinal blood stages and oocysts from feces were compared. Minimum spanning networks were constructed to visualize haplogroups in relation to host specificity and to reveal the identity of various developmental stages. A total of 122 sequences from eight passerine species were used to generate a haplotype network for Lankesterella, and a total of 103 sequences (64 from blood and 39 from feces) was used for Isospora. We detected a total of 36 haplotypes for Lankesterella and 33 haplotypes for Isospora. In Lankesterella, we confirmed that the sedge warbler has its own specific lineages, whereas other warbler species share lineages belonging to three haplogroups; blue, great, marsh and willow tits have their own unique groups of lineages. Isospora is less host-specific than Lankesterella in avian hosts; nevertheless, Isospora sequences from blood and feces were identical in their respective hosts. Our findings provide insights into the diversity and host specificity of blood coccidians; moreover, we molecularly characterized the developmental stages of Isospora.
- Klíčová slova
- Atoxoplasma, Eimeriidae, avian blood parasites, coccidia, host specificity, host–parasite interactions, passerines,
- Publikační typ
- časopisecké články MeSH
The occurrence of avian blood protists is affected by multiple factors that include the characteristics of the hosts, the vectors, the parasites, as well as the environmental factors. This study provides an insight into some of the factors that influence the prevalence of avian Lankesterella, neglected but common blood parasites in breeding populations of common passerines. The highest prevalences of Lankesterella infection were observed in 1 great tit (Parus major) population at 63%, 1 blue tit (Cyanistes caeruleus) population at 49% and a sedge warbler (Acrocephalus schoenobaenus) population at 33%. Prevalence was found to be significantly influenced by sampling site followed by host age, species and sex. Julian date had no significant effect on Lankesterella prevalence. Prevalence data from different sampling sites can reveal different patterns and should be combined critically. Higher prevalence in adults suggest that the infections are chronic, which helps the parasite to persist in host populations. The differences between sexes might be related to different exposure to the transmitting vectors (e. g., mites or mosquitoes) during breeding.
- Klíčová slova
- Acrocephalidae, Apicomplexa, Lankesterellidae, Paridae, avian haemoparasites, coccidia, host–parasite interaction, passerines,
- MeSH
- chov MeSH
- Haemosporida * izolace a purifikace MeSH
- nemoci ptáků * parazitologie epidemiologie MeSH
- Passeriformes * parazitologie MeSH
- prevalence MeSH
- protozoální infekce zvířat * epidemiologie parazitologie MeSH
- sexuální faktory MeSH
- věkové faktory MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články 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.
- Klíčová slova
- Avian blood parasite, Birds of prey, Haemosporida, Parasite persistence, Raptor, Trypanosoma avium, Trypanosoma bennetti, Trypanosoma corvi,
- MeSH
- fylogeneze MeSH
- Haemosporida * genetika MeSH
- incidence MeSH
- některé rody čeledi Accipitridae * parazitologie MeSH
- nemoci ptáků * parazitologie MeSH
- prevalence MeSH
- protozoální infekce zvířat * parazitologie MeSH
- Trypanosoma * genetika MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články 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.
- Klíčová slova
- Hippoboscidae, Ornithoica, Ornithomya, Ornithophila, Trypanosoma, avian parasite, host specificity, transmission,
- Publikační typ
- časopisecké články MeSH
Trypanosomes belonging to Trypanosoma theileri group are mammalian blood parasites with keds and horse fly vectors. Our aim is to study to vector specificity of T. theileri trypanosomes. During our bloodsucking Diptera survey, we found a surprisingly high prevalence of T. theileri trypanosomes in mosquitoes (154/4051). Using PCR and gut dissections, we detected trypanosomes of T. theileri group mainly in Aedes mosquitoes, with the highest prevalence in Ae. excrucians (22%), Ae. punctor (21%), and Ae. cantans/annulipes (10%). Moreover, T. theileri group were found in keds and blackflies, which were reported as potential vectors for the first time. The vectorial capacity was confirmed by experimental infections of Ae. aegypti using our isolates from mosquitoes; sand fly Phlebotomus perniciosus supported the development of trypanosomes as well. Infection rates were high in both vectors (47-91% in mosquitoes, 65% in sandflies). Furthermore, metacyclic stages of T. theileri trypanosomes were observed in the gut of infected vectors; these putative infectious forms were found in the urine of Ae. aegypti after a second bloodmeal. On the contrary, Culex pipiens quinquefasciatus was refractory to experimental infections. According to a phylogenetic analysis of the 18S rRNA gene, our trypanosomes belong into three lineages, TthI, ThII, and a lineage referred to as here a putative lineage TthIII. The TthI lineage is transmitted by Brachycera, while TthII and ThIII include trypanosomes from Nematocera. In conclusion, we show that T. theileri trypanosomes have a wide range of potential dipteran vectors, and mosquitoes and, possibly, sandflies serve as important vectors.
- Klíčová slova
- Phlebotomus, Trypanosoma melophagium, Trypanosoma theileri, ked, mosquito, phylogeny, prediuresis, tabanid, transmission, vector,
- Publikační typ
- časopisecké články MeSH