Low occurrence of hemosporidian parasites in the Neotropic cormorant (Phalacrocorax brasilianus) in Chile

First record and molecular diversity of haemosporidian parasites in Sula leucogaster (Boddaert, 1783) from the southeastern Brazilian coast

Avian haemosporidian parasites are protozoans transmitted by vectors, belonging to the genera Plasmodium, Haemoproteus, and Leucocytozoon, capable of infecting various bird species. The prevalence of these parasites varies depending on factors such as the habitat and geographical location of the host and vector, as well as across different bird groups. Seabirds typically exhibit low infection rates due to the absence of vectors in marine environments. This study aimed to identify and characterize the molecular diversity of Haemosporida parasites in a population of Brown Boobies (Sula leucogaster) (n = 37) from the Santana Archipelago in Macaé, Rio de Janeiro state. We utilized PCR-based detection methods to confirm the presence of haemosporidian parasites and sequencing (ctyb gene) to delineate the lineages. The results uncovered a notable prevalence (48.6%) of haemosporidian parasites (Plasmodium and Haemoproteus), comprising 12 novel lineages and four previously documented lineages (establishing new host records). Our findings suggest that transmission and infection by these hemoparasites can occur both on and off the island. Overall, this study yields valuable insights into the genetic diversity of haemosporidian parasites in Brown Boobies, enriching our understanding of the ecology and epidemiology of these parasites in seabirds.

Global prevalence of Plasmodium infection in wild birds: A systematic review and meta-analysis

Avian malaria is a vector-borne parasitic disease caused by Plasmodium infection transmitted to birds by mosquitoes. The aim of this systematic review was to analyze the global prevalence of malaria and risk factors associated with infection in wild birds. A systematic search of the databases CNKI, WanFang, VIP, PubMed, and ScienceDirect was performed from database inception to 24 February 2023. The search identified 3181 retrieved articles, of which 52 articles met predetermined inclusion criteria. Meta-analysis was performed using the random-effects model. The estimated pooled global prevalence of Plasmodium infection in wild birds was 16%. Sub-group analysis showed that the highest prevalence was associated with adult birds, migrant birds, North America, tropical rainforest climate, birds captured by mist nets, detection of infection by microscopy, medium quality studies, and studies published after 2016. Our study highlights the need for more understanding of Plasmodium prevalence in wild birds and identifying risk factors associated with infection to inform future infection control measures.

First report of Culicoides caucoliberensis in Spain: Exploring molecular phylogeny, host-feeding behaviour and avian haemosporidian parasites

Culicoides biting midges (Diptera: Ceratopogonidae) are vectors of pathogens that affect wildlife and livestock. Understanding the composition and distribution of vector species is crucial for implementing control strategies and preventing the spread of infectious diseases. This study provides a morphological and molecular characterisation of Culicoides caucoliberensis, which represents the first record for Spain, increasing the number of Culicoides species in the country to 85. A total of 213 specimens were collected using Onderstepoort-ultraviolet down-draught light traps on a rocky coastline in the Balearic Islands during two sampling periods in 2022. Phylogenetic analysis showed that C. caucoliberensis forms a monophyletic cluster within the Maritimus group. Host preferences were determined for the first time and showed propensity to feed on the European shag (Phalacrocorax aristotelis). The vector role of C. caucoliberensis for haemosporidian transmission remains unclear since molecular detection of Haemosporidians (Haemoproteus and Plasmodium) was negative for all the pools of parous and engorged females analysed. This study emphasises the importance of conducting entomofauna studies in lesser-known Mediterranean islet landscapes and highlights the need for research on vectors within the One Health framework.

Molecular detection of Leucocytozoon in red-legged seriemas (Cariama cristata), a non-migratory bird species in the Brazilian Cerrado

Avian Haemosporidian parasites - Plasmodium, Haemoproteus, Leucocytozoon and Fallisia - have a wide distribution except for Antarctica. Leucocytozoon sp. has been poorly described in Brazil, and few studies have indicated infections in birds from the Atlantic Forest, Pantanal, Pampa and Amazon biomes. This study describes, for the first time, the occurrence of Leucocytozoon infection in red-legged seriemas (Cariama cristata) in the Brazilian savanna (Cerrado biome) using molecular diagnosis. Leucocytozoon spp. lineage CARCRI01 was detected in three C. cristata, a non-migratory bird, confirming transmission in mid-elevation areas in central Brazil. Further studies are needed to certify whether infections in red-legged seriemas were not abortive and to elucidate Leucocytozoon infection at low altitudes in the Brazilian lands.

Avian haemosporidian parasites of accipitriform raptors

Background

The order Accipitriformes comprises the largest group of birds of prey with 260 species in four families. So far, 21 haemosporidian parasite species have been described from or reported to occur in accipitriform birds. Only five of these parasite species have been characterized molecular genetically. The first part of this study involved molecular genetic screening of accipitriform raptors from Austria and Bosnia-Herzegovina and the first chromogenic in situ hybridization approach targeting parasites in this host group. The aim of the second part of this study was to summarize the CytB sequence data of haemosporidian parasites from accipitriform raptors and to visualize the geographic and host distribution of the lineages.

Methods

Blood and tissue samples of 183 accipitriform raptors from Austria and Bosnia-Herzegovina were screened for Plasmodium, Haemoproteus and Leucocytozoon parasites by nested PCR, and tissue samples of 23 PCR-positive birds were subjected to chromogenic in situ hybridization using genus-specific probes targeting the parasites’ 18S rRNAs. All published CytB sequence data from accipitriform raptors were analysed, phylogenetic trees were calculated, and DNA haplotype network analyses were performed with sequences from clades featuring multiple lineages detected in this host group.

Results

Of the 183 raptors from Austria and Bosnia-Herzegovina screened by PCR and sequencing, 80 individuals (44%) were infected with haemosporidian parasites. Among the 39 CytB lineages detected, 18 were found for the first time in the present study. The chromogenic in situ hybridization revealed exo-erythrocytic tissue stages of Leucocytozoon parasites belonging to the Leucocytozoon toddi species group in the kidneys of 14 infected birds. The total number of CytB lineages recorded in accipitriform birds worldwide was 57 for Leucocytozoon, 25 for Plasmodium, and 21 for Haemoproteus.

Conclusion

The analysis of the DNA haplotype networks allowed identifying numerous distinct groups of lineages, which have not yet been linked to morphospecies, and many of them likely belong to yet undescribed parasite species. Tissue stages of Leucocytozoon parasites developing in accipitriform raptors were discovered and described. The majority of Leucocytozoon and Haemoproteus lineages are specific to this host group, but most Plasmodium lineages were found in birds of other orders. This might indicate local transmission from birds kept at the same facilities (raptor rescue centres and zoos), likely resulting in abortive infections. To clarify the taxonomic and systematic problems, combined morphological and molecular genetic analyses on a wider range of accipitriform host species are needed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-021-04019-z.

First records of prevalence and diversity of avian haemosporidia in snipe species (genus Gallinago) of Japan

Migratory birds are important carriers of pathogens such as viruses, bacteria and protozoa. Avian haemosporidia have been detected from many wild birds of Japan, but the infection status of migratory birds and transmission area are still largely unknown. Gallinago snipes are long-distance migratory shorebirds, and five species migrate to or through Japan, including Latham's snipe which is near threatened. Haemosporidian parasites in four snipe species were investigated to understand the role of migratory birds in the transmission of avian haemosporidia. Namely, this study aimed: i) to investigate differences in parasite prevalence and related factors explaining infection likelihood among these migratory species, ii) to explore the diversity in haemosporidian lineages and possible transmission areas, and iii) to assess the possibility of morphological effects of infection. Blood samples were collected from snipes caught in central and southwest Japan during migration. Parasites cytb gene DNA were detected via PCR-based testing, and detected lineages were phylogenetically analyzed. Additionally, factors related to prevalence and morphological effects of infection were statistically tested. 383 birds from four Gallinago snipe species were caught, showing higher overall prevalence of avian haemosporidia (17.8 %) than reported in other wader species in previous studies. This high infection rate is presumably due to increased contact with vector insects, resultant of environmental preferences. The prevalence of Plasmodium spp. Was higher in Swinhoe's snipes, while Haemoproteus spp. Was higher in Latham's snipes. These differences are thought to be related to ecological factors including habitat use, distribution and migratory route. Six lineages detected from juveniles indicate transmission between the breeding and sampling area. Contrary to expectations, a direct link between morphological features and haemosporidian parasite infection were not detected. These findings provide valuable information for conservation of this endangered migratory bird group. Further studies linking biological and parasitological research are anticipated to contribute to conservational actions.

Haemosporidian Parasites of Chilean Ducks: The Importance of Biogeography and Nonpasserine Hosts

Biogeography is known to have shaped the diversity and evolutionary history of avian haemosporidian parasites across the Neotropics. However, a paucity of information exists for the temperate Neotropics and especially from nonpasserine hosts. To understand the effect of biogeography in the temperate Neotropics on haemosporidians of nonpasserine hosts we screened ducks (Anseriformes) from central Chile for the presence of these parasites. Forty-two individuals of 4 duck species (Anas flavirostris, Anas georgica, Mareca sibilatrix, Spatula cyanoptera cyanoptera) were collected and assessed for haemosporidian parasite infections by real-time polymerase chain reaction screening and subsequent sequencing of the mitochondrial cytochrome b gene. Haemoproteus (subgenus Haemoproteus) and Plasmodium were detected in 2 host species, A. georgica and S. c. cyanoptera, with no Leucocytozoon found. Overall haemosporidian prevalence was low (14.2%), with the prevalence of Plasmodium (11.9%) being substantially greater than that of Haemoproteus (4.8%). Six haemosporidian cytochrome b lineages were recovered, 2 Haemoproteus and 4 Plasmodium, with all 6 lineages identified for the first time. In phylogenetic reconstruction, the Chilean Plasmodium lineages were more closely related to South American lineages from passerine birds than to known lineages from anseriforms. The subgenus Haemoproteus known from nonpasseriformes has never been identified from any anseriform host; however, we recovered 2 lineages from this subgenus, one from each A. georgica and S. c. cyanoptera. Further work is needed to determine if this presents true parasitism in ducks or only a spillover infection. The results of phylogenetic reconstruction demonstrate a unique evolutionary history of these Chilean parasites, differing from what is known for this host group. The unique geography of Chile, with a large part of the country being relatively isolated by the Atacama Desert in the north and the Andes in the east and south, would present opportunities for parasite diversification. Further work is needed to investigate how strongly the biogeographical isolation has shaped the haemosporidian parasites of this area. Our results add to the growing body of evidence that nonpasserine hosts support unique lineages of haemosporidian parasites, while also demonstrating the role of biogeography in haemosporidian parasite diversity in the temperate Neotropics.

Latitudinal gradients of haemosporidian parasites: Prevalence, diversity and drivers of infection in the Thorn-tailed Rayadito (Aphrastura spinicauda)

Latitudinal gradients are well-suited systems that may be helpful explaining distribution of haemosporidian parasites and host susceptibility. We studied the prevalence, diversity and drivers of haemosporidian parasites (Leucocytozoon, Plasmodium and Haemoproteus) along a latitudinal gradient (30°-56° S), that encompass the total distribution (~3,000 km) of the Thorn-tailed Rayadito (Aphrastura spinicauda) in the South American temperate forests from Chile. We analyzed 516 individuals from 18 localities between 2010 and 2017 and observed an overall prevalence of 28.3% for haemosporidian parasites. Leucocytozoon was the most prevalent parasite (25.8%). We recorded 19 distinct lineages (13 for Leucocytozoon, five for Plasmodium, and one for Haemoproteus). Differences in haemosporidian prevalence and diversity by genus and type of habitat were observed in the latitudinal gradient. Further, we support the existence of a latitudinal associate distribution of Leucocytozoids in South America, where prevalence and diversity increase toward higher latitudes. Distribution of Leucocytozoon was associated with sub-antarctic habitat (higher latitude) and explained by cold temperature and high precipitation. On the other hand, we lacked to find a latitudinal associate pattern for Plasmodium and Haemoproteus, however low prevalence and high diversity were recorded in areas considered as a hotspot of biodiversity in Central Chile. Our findings confirmed the importance of habitat and climatic variables explaining prevalence, diversity and distribution of haemosporidian parasites in a huge latitudinal gradient, belonging the distribution of the Thorn-tailed Rayadito in the world's southernmost forests ecosystems.