Naturally Acquired Humoral Immunity against Malaria Parasites in Non-Human Primates from the Brazilian Amazon, Cerrado and Atlantic Forest.

Plasmodium - Plasmodium brasilianum - P. malariae - P. malariae - P. falciparum - P. vivax - Plasmodium content: - "Non-human primates (NHPs) have been shown to be infected by parasites of the genus " - ", the etiological agent of malaria in humans, creating potential risks of zoonotic transmission. " - ", a parasite species similar to " - " of humans, have been described in NHPs from Central and South America, including Brazil. The merozoite surface protein 1 (MSP1), besides being a malaria vaccine candidate, is highly immunogenic. Due to such properties, we tested this protein for the diagnosis of parasite infection. We used recombinant proteins of " - " MSP1, as well as of " - " and " - ", for the detection of antibodies anti-MSP1 of these parasite species, in the sera of NHPs collected in different regions of Brazil. About 40% of the NHP sera were confirmed as reactive to the proteins of one or more parasite species. A relatively higher number of reactive sera was found in animals from the Atlantic Forest than those from the Amazon region, possibly reflecting the former more intense parasite circulation among NHPs due to their proximity to humans at a higher populational density. The presence of " - " positive NHPs in the surveyed areas, being therefore potential parasite reservoirs, needs to be considered in any malaria surveillance program.

Plasmodium spp. in wild birds in São Paulo Zoo: identification with microscopy and amplification of mithocondrial cytochrome b gene

O papel dos Zoológicos nos programas de conservação aumentou significantemente nas últimas décadas e a manutenção da saúde dos animais cativos é essencial para garantir o sucesso desses programas. Entretanto, aves mantidas em zoos sofrem de infecções por parasitas, principalmente hemosporídeos, e podem perecer em quase todo o mundo. Estudos para determinar a ocorrência e diversidade desses parasitas, com o objetivo de entender melhor sua influência na condição física das aves em cativeiro, são necessários. Em um estudo de quase quatro anos, nós investigamos a positividade de Plasmodium spp. e Haemoproteus spp. nas aves cativas do Parque Zoológico de São Paulo, o maior zoológico da América Latina e o quarto do mundo. Métodos moleculares e morfológicos foram usados para detectar e identificar esses parasitas. A positividade geral de hemosporídeos nos indivíduos examinados foi 12,6%. Os parasitas foram detectados, sobretudo, através do diagnóstico molecular, indicando que muitas espécies podem abrigar infecções subclínicas. Em um estudo amplo, nós testamos animais de 17 Ordens, 29 Famílias, e 122 espécies, detectando indivíduos positivos em 64,7%, 48,3% e 27%, respectivamente. Aves da Família Anatidae foram as mais frequentemente infectadas. As infecções com parasitas do gênero Plasmodium foram predominantes quando comparadas aquelas com parasitas do gênero Haemoproteus. No total, 14 linhagens de cytb de Plasmodium spp., incluindo P. nucleophilum e P. elongatum, e 2 linhagens de cytb de Haemoproteus spp., foram registradas. Dessas linhagens, 8 foram descritas pela primeira vez. Uma dessas linhagens foi notavelmente generalista quanto às espécies hospedeiras, enquanto outras se restringiram a parasitar espécies de uma mesma Família. Estes resultados mostram que entre os animais cativos dos zoos, além dos pinguins, existem várias espécies em risco de contrair malária. A presença de Haemosporida pode ser difícil de eliminar, mas é possível reduzir a taxa de infecção tratando os animais positivos, enquanto os mantêm em instalações livres de mosquitos. Protocolos de quarentena precisam ser utilizados se o animal for transferido entre instituições. O presente estudo é o primeiro inquérito de hemosporídeos realizado em aves cativas de diferentes Ordens, e enfatiza a necessidade de incluir, na gestão e criação desses animais no cativeiro, práticas para o controle desses parasitas.The role of Zoos in conservation programs has increased significantly in last decades and maintenance of the health of captive animals is essential to guarantee the success of these programs. However, birds kept in zoos suffer from infections by parasites, mainly haemosporidians, and can perish almost everywhere in the world. Studies to determine the occurrence and diversity of these parasites, aiming to better understand its influence in the fitness of the captive birds, are necessary. In a study over four years, we investigated the positivity of Plasmodium spp. and Haemoproteus spp. in the captive birds from the São Paulo Zoo, the largest zoo in Latin America and the fourth in the world. Molecular and morphological methods were used for detecting and identifying these parasites. The overall positivity of haemosporidians in the examined birds was 12.6%. Parasites were mostly detected by the molecular diagnosis, indicating that many bird species may harbour subclinical infections. In a very wide study, we tested animals from 17 Orders, 29 Families, and 122 different species, detecting positive individuals in 64.7%, 48.3% and 27%, respectively. Birds from the Anatidae Family were the most commonly infected animals. Infections with parasites of the genus Plasmodium were predominant when compared to those of the genus Haemoproteus. In total, 14 cytb lineages of Plasmodium spp., including P. nucleophilum and P. elongatum, and 2 cytb lineages of Haemoproteus spp., were recorded in this study. From these lineages, 8 were described for the first time. One of these lineages was markedly generalist regarding the host species while others infected just species within the same Family. These results show that among the captive animals in the zoos, besides the penguins, there are many species at risk of acquiring malaria. The presence of Haemosporida could be difficult to eliminate, but it is possible to reduce the infection rate by treating the positive animals, while keeping them in facilities free from mosquitoes. Protocols of quarantine must be implemented whenever an animal is transferred between institutions. The present study is the first survey of haemosporidians carried out with captive birds from different Orders, and emphasizes the necessity of applying, in management and husbandry of animals in captivity, practices to control these parasites

Description and molecular characterization of two species of avian blood parasites, with remarks on circadian rhythms of avian Haematozoa infectionsv

Simple Summary The diversity of avian blood parasites is remarkable, and they are often found in co-infections, which is a challenge for wildlife parasitology research. Co-infections not only make parasite morphological and molecular identification difficult, but also might influence the infection dynamics and disease manifestation. This study investigated blood parasites infections in a Eurasian blackbird (Turdus merula) and a Song thrush (Turdus philomelos). A new Lankesterella species was found and described. The molecular characterization of this parasites as well as Splendidofilaria mavis, an avian filarioid nematode, was developed. As several blood infections were present in co-infection, we used this opportunity to investigate the daily changes in the parasite intensity seen in the blood of these birds. A peak of the Plasmodium matutinum parasitemia was seen during the daytime. Leucocytozoon spp. showed some parasitemia peaks close to the evening and night. Trypanosoma spp. and S. mavis parasitemia increased during the night. Data about daily variation of Haemoproteus, Lankesterella, and S. mavis parasites were obtained for the first time. No pattern in parasitemia dynamics was identified in Haemoproteus and Lankesterella infections. Avian blood parasites are remarkably diverse and frequently occur in co-infections, which predominate in wildlife. This makes wildlife pathogen research challenging, particularly if they belong to closely related groups, resulting in diagnostic problems and poor knowledge about such infections as well as the patterns of their co-occurrence and interactions. This is particularly true due to the periodicity (circadian rhythms) of parasitemia, which means that different parasitemia and parasite stages might be found throughout the day. We analysed blood samples from a Eurasian blackbird (Turdus merula) and a Song thrush (Turdus philomelos). This study aimed to describe a new avian Lankesterella species and molecularly characterize and redescribe Splendidofilaria mavis, a common avian filarioid nematode. Additionally, it was possible to investigate the circadian rhythms of the avian blood parasites belonging to Plasmodium, Haemoproteus, Leucocytozoon, and Trypanosoma, which occurred in co-infection in the same avian host individuals. Different circadian rhythms were seen in different parasites, with Plasmodium sp. peaks occurring at midday, Leucocytozoon spp. peaks mainly during the evening and night, and Trypanosoma spp. and microfilariae peaks at midnight. No periodicity was seen in Haemoproteus and Lankesterella species infections. The time of parasitemia peaks most likely coincides with the time of vectors' activity, and this should be beneficial for transmission. Knowledge about the circadian rhythms is needed for better understanding patterns in host-parasite interactions and disease transmission

Molecular and morphological characterization of three new species of avian Onchocercidae (Nematoda) with emphasis on circulating microfilariae

Background: Blood parasites have been the subject of much research, with numerous reports of the presence of microfilariae in the peripheral blood (circulating microfilariae) of birds belonging to many orders. Current limitations in molecular characterization methods and species identification using morphological characters of circulating microfilariae are major obstacles to improving our understanding the biology of Filarioidea species, particularly in wildlife. The aim of this study was to partially fill these gaps, with particular emphasis on morphological features of microfilariae, which are the most readily accessible stages of these pathogens. Methods: Peripheral blood samples of 206 birds belonging to genera Acrocephalus (five species) and Sylvia (five species) were examined using the buffy coat method to process the blood samples for the presence of microfilariae. Positive birds were dissected to collect adult nematodes. Microfilariae and adult nematodes were described, and sequences of their mitochondrial cytochrome c oxidase subunit I and nuclear 28S rDNA gene fragments were obtained and used for molecular characterization and Bayesian phylogenetic inferences. Results: Overall prevalence of microfilariae was 2.9%. Microfilariae were found in the blood samples from six birds (2 Acrocephalus scirpaceus and 1 each of A. arundinaceus, Sylvia atricapilla, S. borin and S. curruca), which were dissected. All parasite species observed were new. Eufilaria acrocephalusi sp. n. and Eufilaria sylviae sp. n. were present in subcutaneous, peritracheal and periesophageal connective tissues in A. scirpaceus and S. borin, respectively. Splendidofilaria bartletti sp. n. was found in finger joins of S. atricapilla. Illustrations of microfilariae and adult nematodes are shown, and morphological and phylogenetic analyses identified the DNA barcode haplotypes that are associated with these species. Phylogenetic analysis places the parasites of different genera in different closely related clades. Conclusions: Adult nematode morphological characters, which have been traditionally used in the taxonomy of Filarioidea species, have a phylogenetic value. Importantly, in our study parasites of different genera were readily distinguishable based on the morphology of their microfilariae. The link between molecular and morphology data requires more study in Filarioidea species research, particularly because this approach provides new knowledge on species identity using only readily accessible blood stages (microfilariae), thereby avoiding host dissection and thus minimizing harm to wildlife during research

Prevalence and diversity of blood parasites (Plasmodium, Leucocytozoon and Trypanosoma) in backyard chickens (Gallus gallus domesticus) raised in Southern Thailand

Avian malaria and leucocytozoonosis can cause fatal diseases, whereas avian trypanosomiasis is reported to be harmless in chickens. Backyard chickens can be infected by several pathogens, including blood parasites, that may shed to industrial poultry production, with a consequently higher economic impact. This study aimed to investigate the presence of several blood parasites (Plasmodium, Leucocytozoon and Trypanosoma) in backyard chickens raised in Southern Thailand, using PCR-based detection and microscopic methods. From June 2021 to June 2022, 57 backyard chickens were sampled. Fresh thin blood smears were prepared from 11 individuals, and buffy coat smears were prepared from 55 of them. Both thin blood smears and buffy coat smears were used for microscopic analysis. Two nested PCR protocols that amplify a fragment of cytochrome b (cytb) and small subunit rRNA (SSU rRNA) genes were used to identify Haemosporida and Trypanosoma parasites, respectively. The number of positive samples was higher with the application of nested PCR than when buffy coat smears were used. Three new Plasmodium lineages (GALLUS47-49) and thirteen Leucocytozoon lineages (GALLUS50-62) were found. Trophozoites, meronts and gametocytes of Plasmodium gallinaceum (GALLUS01) were present in one thin blood smear. All thin blood smears revealed Leucocytozoon infections, but only three samples were a single infection. These three samples revealed the presence of fusiform host cell–parasite complexes, of which the morphological features resembled those of Leucocytozoon macleani (possible synonym is Leucocytozoon sabrazesi), while the cytb showed that this parasite is closely related to the lineage GALLUS06-07, described as Leucocytozoon schouteni. The Trypanosoma prevalence was 33.33%; it was present in only one of the thin blood smears, and it resembles Trypanosoma calmettei. This study showed the prevalence of a high diversity of Plasmodium (64.91%) and Leucocytozoon (89.47%) in Thai chickens. Both nested-PCR and buffy coat smear can be used as the diagnostic tool for the testing of Plasmodium, Leucocytozoon and Trypanosoma for parasitic control in backyard chickens and poultry farms. The information on the parasite species that can be found in chickens raised in Southern Thailand was also considered as the baseline information for further study

A new blood parasite of leaf warblers: molecular characterization, phylogenetic relationships, description and identification of vectors

Abstract Background Blood parasites of the genus Haemoproteus Kruse, 1890 are cosmopolitan, might be responsible for mortality in non-adapted birds, and often kill blood-sucking insects. However, this group remains insufficiently investigated in the wild. This is particularly true for the parasites of leaf warblers of the Phylloscopidae Alström, Ericson, Olsson & Sundberg the common small Old World passerine birds whose haemoproteid parasite diversity and vectors remain poorly studied. This study reports a new species of Haemoproteus parasitizing leaf warblers, its susceptible vector and peculiar phylogenetic relationships with other haemoproteids. Methods Wood warblers (Phylloscopus sibilatrix Bechstein) were caught in Lithuania during spring migration, and blood films were examined microscopically. Laboratory reared Culicoides nubeculosus Meigen were exposed experimentally by allowing them to take blood meals on one individual harbouring mature gametocytes of the new Haemoproteus species (lineage hPHSIB2). To follow sporogonic development, the engorged insects were dissected at intervals. The parasite lineage was distinguished using sequence data, and morphological analysis of blood and sporogonic stages was carried out. Bayesian phylogeny was constructed in order to determine the phylogenetic relationships of the new parasite with other haemoproteids. Results Haemoproteus (Parahaemoproteus) homopalloris n. sp. was common in wood warblers sampled after arrival to Europe from their wintering grounds in Africa. The new parasite belongs to a group of avian haemoproteid species with macrogametocytes possessing pale staining cytoplasm. All species of this group clustered together in the phylogenetic analysis, indicating that intensity of the cytoplasm staining is a valuable phylogenetic character. Laboratory-reared biting midges C. nubeculosus readily supported sporogony of new infections. Phylogenetic analysis corroborated vector experiments, placing the new parasite in the clade of Haemoproteus (Parahaemoproteus) parasites transmitted by biting midges. Conclusions Haemoproteus homopalloris n. sp. is the third haemoproteid, which is described from and is prevalent in wood warblers. Phylogenetic analysis identified a clade containing seven haemoproteids, which are characterised by pale staining of the macrogametocyte cytoplasm and with ookinetes maturing exceptionally rapidly (between 1 to 1.5 h after exposure to air). Both these features may represent valuable phylogenetic characters. Studies targeting mechanisms of sporogonic development of haemoproteids remain uncommon and should be encouraged. Culicoides nubeculosus is an excellent experimental vector of the new parasite species

What can haemosporidian lineages found in Culicoides biting midges tell us about their feeding preferences?

Haemoproteus (Parahaemoproteus) parasites are transmitted by Culicoides biting midges. However, the natural vectors of only six of the almost 180 recognized Haemoproteus species have been identified. The aim of this study was to investigate wild biting midges naturally infected with Haemoproteus and to understand the interaction network between Culicoides and Haemoproteus in Europe. Culicoides were collected with UV light traps from different sites in Lithuania. Parous females were morphologically identified based on their wings and heads. PCR-based methods were used to detect the Haemoproteus DNA, and salivary gland preparations were analyzed for the presence of sporozoites. Of the 580 Culicoides analyzed, 5.9% were positive for Haemoproteus DNA, and sporozoites were found in two of 11 sampled biting midge species: Culicoides kibunensis and Culicoides segnis. The interaction network revealed that C. kibunensis and C. segnis are frequently associated with several Haemoproteus lineages. On the other hand, some Haemoproteus lineages were found to interact with only one Culicoides species. This was the first report of C. segnis being a competent vector for H. minutus TURDUS2, H. asymmetricus TUPHI01, H. majoris PHSIB1, and H. fringillae CCF3; and of C. kibunensis being a competent vector for H. belopolskyi HIICT1. Culicoides segnis and C. kibunensis are both important vectors of Haemoproteus parasites

Host cells of Leucocytozoon (Haemosporida, Leucocytozoidae) gametocytes, with remarks on the phylogenetic importance of this character

Leucocytozoon parasites remain poorly investigated in comparison to other haemosporidians. The host cell inhabited by their blood stages (gametocytes) remains insufficiently known. This study aimed to determine the blood cells inhabited by Leucocytozoon gametocytes in different species of Passeriformes and to test if this feature has a phylogenetic importance. We microscopically analyzed blood films stained with Giemsa from six different bird species and individuals and used PCR-based methods for parasite lineage identification. The DNA sequences obtained were applied for phylogenetic analysis. Leucocytozoon parasite from the song thrush Turdus philomelos (cytochrome b lineage STUR1), the blackbird Turdus merula (undetermined lineage), the garden warbler Sylvia borin (unknown lineage) inhabited erythrocytes, a parasite from the blue tit Cyanistes caeruleus (PARUS4) infects lymphocytes, while in the wood warbler Phylloscopus sibilatrix (WW6) and the common chiffchaff Phylloscopus collybita (AFR205) they were found inhabiting thrombocytes. Parasites infecting thrombocytes were closely related, while the parasites infecting erythrocytes were placed in three different clades, and the one found in lymphocytes was placed in a separate clade. This shows that the determination of host cells inhabited by Leucocytozoon parasites can be phylogenetically important and should be considered in future species descriptions. Noteworthy, phylogenetic analysis might be used for the prediction of which host cells parasite lineages might inhabit

Exo-erythrocytic development of Leucocytozoon parasites (Haemosporida, Leucocytozoidae) in song thrushes Turdus philomelos

Leucocytozoon parasites (Haemosporida, Leucocytozoidae) are haemosporidians whose diversity, exo-erythrocytic development and potential vectors are the least studied. The knowledge about their exo-erythrocytic development and pathogenicity is fragmentary, resulting in an incomplete comprehension of the impact of these parasites on avian hosts. For a long time, Leucocytozoon infections were considered benign to wild birds, even though they were virulent in poultry and responsible for some wild bird population declines. This study aimed to investigate the presence of Leucocytozoon species exo-erythrocytic stages in song thrushes Turdus philomelos using conventional histological techniques (sections stained by H&E) and chromogenic in situ hybridization (CISH). Tissues from ten birds (seven naturally infected and three opportunistic samplings) were examined using both methods. Parasite lineages were identified from blood samples using PCR-based techniques. Leucocytozoon species meronts were found in five individuals (in four birds using H&E staining protocol, and in three in CISH-treated histological sections). Meronts were found mainly in the kidneys, but some meronts were also present in the lungs. It was possible to observe different maturation stages of meronts in the same bird individual, indicating an asynchronous development. Cytomeres were readily visible in developing meronts. One megalomeront-like structure was present close to a blood vessel in the heart. It was covered with a prominent capsular-like wall. No inflammatory reaction or necrosis was seen in the tissues surrounding the meronts or the megalomeront-like structure. We could confirm the transmission of three Leucocytozoon lineages (lTUPHI14, lSTUR1 and lTUPHI13) in Europe, and add evidence of the transmission of two Plasmodium lineages, including Plasmodium circumflexum (pTURDUS1), and Haemoproteus asymmetricus (hTUPHI01). We call for further research to better understand Leucocytozoon parasite exo-erythrocytic development