Dataset Information

Neglected parasite reservoirs in wetlands: Prevalence and diversity of avian haemosporidians in waterbird communities in Northeast China.

ABSTRACT: The diversity of waterbirds is threatened, and haemosporidian parasite infection is considered one of the most important causative factors. However, to date, only a few studies focusing on specific parasite species have been carried out, which cannot reflect the general patterns at the community level. To test whether the reported haemosporidian diversity in waterbirds is underestimated, we estimated the prevalence and lineage diversity of avian haemosporidian parasites in 353 waterbirds from 26 species in the Tumuji National Nature Reserve, Northeast China, as well as the host-parasite associations. According to the molecular analysis of cytochrome b (cyt b) barcode sequences, 28.3% of the birds were infected by 49 distinct parasite lineages, including 11 Plasmodium, 12 Haemoproteus, and 26 Leucocytozoon lineages, of which 39 were novel. The highest prevalence was contributed by Leucocytozoon (13.31%), followed by Plasmodium (13.03%) and Haemoproteus (4.25%), which suggested that waterbirds were infected to a lesser extent by Haemoproteus than by the other two genera. Among the most sampled birds, species belonging to Anatidae appeared to be susceptible to Leucocytozoon but resistant to Plasmodium, while Rallidae presented the opposite pattern. On the phylogenetic tree, most of the Leucocytozoon lineages detected in Anatidae clustered together and formed two well-supported clades, while lineages restricted to Gruidae were distantly related to other parasites in all three genera. SW5 was the most abundant lineage and therefore might be a major threat to waterbirds; among the hosts, the common coot harboured the highest diversity of parasite lineages and thus could act as a reservoir for potential transmission. This is the first study of avian haemosporidian infections in a wild waterbird community in Asia. Our findings have doubled the number of lineages recorded in waterbirds, broadened our understanding of host-parasite associations, and addressed the importance of studying haemosporidian infections in wild waterbird conservation.

SUBMITTER: Yang G

PROVIDER: S-EPMC8182418 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BackgroundBirds harbour an astonishing diversity of haemosporidian parasites. Renewed interest in avian haemosporidians as a model system has placed a greater emphasis on the development of screening protocols to estimate parasite prevalence and diversity. Prevalence estimates are often based on the molecular or blood-smear microscopy techniques. However, variation in diagnostic sensitivity among screening methodologies represents a potential source of bias that may lead to erroneous inference in comparisons of prevalence across studies. Here, we analyzed a suite of blood samples for the presence of parasites using four diagnostic tools and compared method-specific estimates of detection probability to assess the relative performance of screening strategies.MethodsWe screened a total of 394 bird blood samples collected in India (n = 203) and Sweden (n = 191) for the combined presence of Plasmodium, Haemoproteus and Leucocytozoon with three PCR assays: (i) qPCR; (ii) restriction enzyme-based assay; and (iii) nested protocol. In addition, we examined blood smears for estimates of parasite intensity which was further screened using qPCR method to evaluate if parasite intensity shows a relationship with qPCR (Ct values). Furthermore, we used single infected samples from parasite intensities: low, medium, high, very high to establish the reproducibility in qPCR.ResultsFor the combined data sets from India and Sweden, detection probability for submicroscopic and low intensity infections was highest for the qPCR method, followed by the nested protocol and the restriction enzyme-based assay. For high parasite intensities, the qPCR had high PCR reproducibility, with three out of three PCR replicates being positive and with consistent Ct values across all tenfold dilution series. For parasite intensities at very low and submicroscopic samples, the qPCR was reproducible in one out of the three replicates. The intensity of parasitemia estimated from smears showed inverse relationship with Ct values in both the Indian and Swedish data sets.ConclusionsOur study highlights the importance of accounting for methodological issues to better estimate infection in parasitological studies and illustrates how a wider deployment of diagnostic tools combined with statistical approaches is needed for each study, in order to provide adequate insight into the most appropriate approach to avoid erroneous inferences.

Project description:We described the geographic distribution of 82 haemosporidian lineages (Plasmodium, Haemoproteus, and Leucocytozoon) in the cattle egret sampled in five countries in central-western and southern Africa. Seventy-three lineages have not previously been reported. We determined the prevalence of three haemosporidians in the samples. We investigated the influence of the internal environment of the host and environmental variables on the Plasmodium diversity and whether environmental variables may explain spatial variations in the prevalence of Plasmodium. We screened DNA from 509 blood samples from nestlings in 15 African colonies for infection by sequencing the cytochrome b gene of parasites. The molecular phylogenetic analysis was performed using Bayesian methods and including sequences from the MalAvi and GeneBank databases. We found 62 new Plasmodium lineages in a clade with MYCAME02, which is a lineage described in waterbirds and recently identified in birds of prey as Plasmodium paranucleophilum. Two Haemoproteus lineages identified in cattle egret formed a distinct group with Haemoproteus catharti and MYCAMH1 (Haemoproteus spp.). Seven Leucocytozoon lineages found in the cattle egret clustered with Leucocytozoon californicus. We found different Plasmodium diversities among the colonies sampled, demonstrating that the internal environment of the host is not the primary determinant of diversity. A linear mixed-effects multivariate model showed that precipitation was positively associated with Plasmodium diversity when controlling for the effects of temperature, colony composition (mixed and non-mixed species) and country. Moreover, a generalized mixed model showed that temperature was positively associated with the prevalence of Plasmodium when controlling for precipitation, elevation and country. We conclude that the cattle egret is a good model for future haemosporidian studies, as we found a significant number of new lineages in this host, which occupies regions with different climate characteristics where environmental variables exert an influence on the diversity and prevalence of Plasmodium.

Dataset Information

Neglected parasite reservoirs in wetlands: Prevalence and diversity of avian haemosporidians in waterbird communities in Northeast China.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets