Despite their ecological importance and protected status, the diversity, host associations, and evolutionary relationships of coccidia infecting shrews (Eulipotyphla: Soricidae) remain poorly understood. In particular, the extent of host specificity, the occurrence of host-switching events, and the relationships among coccidian lineages infecting different shrew hosts remain unclear. Here, we investigated coccidian diversity and phylogenetic relationships across several shrew genera and species to clarify parasite-host associations and provide new insights into the evolutionary processes shaping coccidian diversity in shrews. Fecal samples from 188 shrews representing the genera Crocidura, Neomys, Sorex, and Suncus, collected across multiple localities in Europe and two localities in Asia, were examined. Coccidia were detected in one quarter of the samples, generally at low intensities. Phylogenetic analyses based on partial COX1, COX3, and 18S rRNA sequences identified four distinct clusters: three were host-specific (two associated with Crocidura and one with Neomys), whereas one lineage was shared among Crocidura, Neomys, and Sorex. Two Isospora sequences from Sorex araneus clustered with isosporans previously reported from moles. No clear geographic structuring was observed, and the phylogenetic structure also did not mirror the observed morphological characters. The results indicate that host switching and subsequent repeated dispersal occur in eimerians of shrews, suggesting that these processes may be more widespread across small-mammal hosts than previously recognized. The findings expand current knowledge on coccidian diversity in shrews and provide new insights into the host specificity, ecology, and evolutionary dynamics of the parasitic protists.

A new coccidian species, Isospora melanotidis n. sp. from the blue mockingbird Melanotis caerulescens (Swainson), from Morelia, Michoacán State, Mexico. It is described and characterized molecularly. Sporulated oöcyst of the new species are subspherical, 25‒29 × 21‒25 (26.9 × 23.1) µm, (n = 30), with a length/width (L/W) ratio 1.0‒1.1 (1.04). Wall bi-layered 0.6‒1.1 (0.8) thick, clear outer and dark interior. One polar granule present, but micropyle and oöcyst residuum are absent, Sporocysts are ovoidal, measuring on average 14‒22 × 10‒13 (16.6 × 10‒13) µm, with a L/W ratio of 1.5; Stieda, sub-Stieda and para-Stieda bodies are present. A sporocyst residuum is present as a diffuse mass of granules. The 18S rRNA gene loci segment of Isospora sp., used for phylogenetic analysis by means of a maximum likelihood (ML) tree, revealed that Isospora sp., from M. caerulescens is distinct from Isospora sp., from Bewick's Wren Thryomanes bewickii, with node support and bootstrap length of 91.5%. To date, this is the third report on Isospora Schneider 1881 (Apicomplexa: Eimeriidae), which infects Passeriformes of the Mimidae family of the Americas.

Corvids, including crows, magpies, ravens and jays, are among the most abundant and adaptable bird species in urban and peri-urban environments, where their proximity to humans and domestic animals may facilitate the circulation of parasites. This study aimed at analyzing the presence of DNA of Toxoplasma gondii, Neospora caninum and other coccidia with neurotropism in corvids. A total of 279 brain samples collected at two peri-urban locations in Hungary were examined using molecular methods. The majority of sampled individuals were Eurasian magpies (Pica pica; n = 273). In addition, Eurasian jays (Garrulus glandarius; n = 4) and hooded crows (Corvus cornix; n = 2) were included. Apicomplexan DNA was only detected in the brain of P. pica. In this species, T. gondii was identified with a prevalence of 3.7%, for the first time in P. pica in Hungary and Central Europe. Furthermore, DNA of a Lankesterella sp. was detected in 4% of the specimens of P. pica examined, representing the first molecular evidence of its presence in any corvid species. Because the 18S rRNA sequence of this Lankesterella sp. showed at least 1.3% sequence difference from already reported isolates/species but was 100% identical among all 11 infected P. pica at two locations, this isolate may represent a host-associated genotype. DNA of both T. gondii and Lankesterella sp. was detected in three birds. In the brain of one P. pica, an Isospora species was detected, showing the closest sequence identity to Isospora phylidonyrisae and Isospora coronoideae, which have so far been reported from avian hosts in Australia. These findings broaden our knowledge on the diversity of apicomplexan parasites harbored by P. pica and provide a basis for future studies assessing the potential One Health significance of corvids in urban environments.

Passerine birds are highly susceptible to Isospora infections, yet the coccidian fauna of endemic Taiwanese avifauna remains largely unexplored. Here, we describe Isospora kwongchungi n. sp. (Apicomplexa: Eimeriidae) from the Taiwan Blue Magpie (Urocissa caerulea, Corvidae), utilizing an integrative taxonomic approach. Morphological characterization was complemented by Sanger sequencing of the nuclear 18S ribosomal RNA (rRNA) gene (1,679 bp) and Oxford Nanopore Technologies (ONT) long-read sequencing of the complete mitochondrial genome (6,251 bp). Sporulated oocysts are subspherical to spherical (28.9 × 26.4 μm) with a smooth, single-layered wall, possessing both a polar granule and a distinct oocyst residuum. Sporocysts are ovoid (22.3 × 13.6 μm) and feature a knob-like to bubble-shaped Stieda body, a rounded substieda body, and a compact ellipsoidal sporocyst residuum. While the 18S rRNA gene phylogeny exhibited limited intrageneric resolution, the concatenated tree of three mitochondrial protein-coding genes robustly placed I. kwongchungi n. sp. in a clade with Isospora spp. from the invasive Javan myna (Acridotheres javanicus, Sturnidae) and the American robin (Turdus migratorius, Turdidae). This study establishes a molecular anchor for corvid-associated Isospora and highlights the efficacy of combining traditional and next-generation sequencing in resolving the evolutionary dynamics of wildlife parasites.

Cystoisospora (formerly known as Isospora) are apicomplexan intracellular parasites that frequently infect the small intestine of dogs, causing diarrhea, abdominal discomfort, and, in severe cases, death, particularly in young dogs. The research designed to determine the frequency of cystoisosporiasis, identify the species, and evaluate the genetic diversity of the 18S rRNA gene among isolates in Sulaymaniyah, Iraq. The research was carried out in the province of Sulaymaniyah between July and December of 2024. A total of 258 fecal specimens from dogs were collected and examined to diagnose Cystoisospora spp. infection. The traditional Sheather's fecal flotation method was used for the detection of Cystoisospora canis oocysts, while polymerase chain reaction (PCR) and 18S rRNA gene sequencing were performed for molecular confirmation and sequence analysis of C. canis. The infection rate of cystoisosporiasis was 20/258 (7.75%), with the infection occurring significantly more often (P < 0.05) in stray dogs (11.35%) compared to domestic dogs (3.42%), in dogs with watery diarrhea (26.31%) versus those with semi-formed and formed feces (8.89% and 1.54%, respectively), and in puppies (11.45%) compared to adults (3.94%). Comparison and analysis of partial 18S rRNA gene sequences of the protozoa were performed on 20 local isolates identified in the study region. Five of these isolates showed similarity to sequences previously deposited in GenBank, while fifteen isolates exhibited nucleotide variations in the partial 18S rRNA gene sequences compared with previously reported isolates and were documented for the first time in this research area. Phylogenetic analyses revealed a close relationship between C. canis from different countries. These findings provide essential baseline data for dog owners and the veterinary community regarding the presence of this canine coccidian and its risk factors. Additionally, the research offers a valuable molecular dataset for C. canis, crucial for understanding phylogenetic relationships and identifying these protozoans.

Within lizards, chameleons (family Chamaeleonidae) represent a distinctive and highly specialized clade of insectivorous reptiles. Chameleons have become more popular as reptile pets in recent years worldwide, due to their feasible husbandry and attractiveness. To date, not only reptile pet numbers but also health-compromising endoparasite infections are rising. In the current study, we analyzed a total of 670 faecal samples of 25 different chameleon species kept as pet animals all over Germany. In total, 223 animals (33%) were found to harbor gastrointestinal parasites. In total, 10 different parasite taxa were diagnosed in chameleon faecal samples. The most prevalent parasite stages were oxyurid eggs (14.1%), followed by coccidia oocysts (7.8%) (e.g. Isospora jaracimrmani, Isospora spp., Choleoeimeria spp., Eimeria spp.), flagellated protozoan trophozoites (6.3%) (e.g. Leptomonas spp., Tritrichomonas spp., Proteromonas spp.), heterakid eggs (3.6%), thin-shelled nematode eggs (3.6%), digenean trematode eggs (0.6%), pentastomid eggs (0.3%), ascarid eggs (0.2%), Entamoeba spp. cysts (0.2%) and physalopteroid eggs (0.2%). Among current chameleon species, veiled chameleons (Chamaleo calyptratus) showed a significantly higher prevalence of oxyurid infections (64%) than other chameleon species. Co-infections were diagnosed in 9.8% (22/223) of faecal samples. When performing necropsies, 19/31 chameleons showed parasite-induced pathologies based on histopathological examinations, including one animal being infected with 4 parasite species (Leptomonas spp., Tritrichomonas spp., Foleyella furcata and Hexametra angusticaecoides), thereby most likely impacting animal's welfare.

Isosporiasis is caused by apicomplexan protozoa of the genus Isospora, transmitted primarily via the fecal-oral route. While Isospora infects various vertebrates, infections are particularly notable in birds. However, the phylogeography and genetic structure of avian Isospora remain poorly documented. In total, 273 selected mitochondrial cytochrome c oxidase subunit I (COI) sequences belonging to avian Isospora species were retrieved from NCBI and subsequently analyzed to understand their phylogeographic patterns. Overall, 119 haplotypes, predominated by Hap_2, were identified across 17 countries. The dataset exhibited high haplotype diversity (Hd = 0.944) and low nucleotide diversity (π = 0.009). Significantly negative values of Tajima's D (-2.646) and Fu's Fs (-203.014) are compatible with recent demographic expansion under a single‑species assumption, though the presence of cryptic species cannot be excluded. Analysis of molecular variance (AMOVA) showed that 95.26 % of the total genetic variation was attributable to within-population differences suggesting substantial gene flow among most continental populations. Pairwise FST values were low between Europe and North America (0.017) and between Oceania and Europe (0.051, non-significant), but higher between Africa and other continents (0.24-0.34), indicating relative isolation of African lineages In summary, we report substantial haplotype diversity, a dominant cosmopolitan lineage, and contrasting patterns of connectivity - high gene flow among most regions but significant differentiation involving Africa - based on available COI sequences.

Cystoisospora belli, also known as Isospora belli, is an opportunistic pathogen which predominantly affects individuals with compromised immunity, including transplant recipients and patients with AIDS, HTLV-1 infections, or hematologic malignancies. The primary symptom of C. belli infection is diarrhea, but the rarity of C. belli infection makes C. belli an uncommon etiology in patients with diarrhea. Only sporadic cases of C. belli infection have been documented in the past century. Diagnosis of C. belli infection in non-endemic regions poses a challenge and delays can escalate mortality risks. This report detailed a unique case of C. belli infection from Guangxi, China involving a male with an intact immune system and no underlying tumor who presented with prolonged diarrhea and bile duct dilatation. C. belli was identified in bile based on acid-fast staining, a rare diagnosis in mainland China and globally. The patient was treated with sulfamethoxazole tablets following diagnosis and responded favorably with significant clinical improvement. This case underscores the importance of considering C. belli in the differential diagnosis of patients with unexplained diarrhea and hepatic ductal dilatation, even though the patient had normal immune function. This finding highlights the need for increased awareness and diagnostic vigilance in both endemic and non-endemic regions.

The Red-crowned Ant-tanager Habia rubica (Vieillot, 1817) is a forest-dependent passerine that inhabits the understory of humid forests and is widely distributed throughout Central and South America, extending northward into Mexico. Wild birds may host a broad diversity of parasites, among which coccidia constitute one of the most species-rich and taxonomically complex groups. Within this context, the present study reports a new species of Isospora Schneider, 1881 parasitizing Red-crowned Ant-tanagers captured in Itatiaia National Park, a protected area of high ecological vulnerability in southeastern Brazil. The oocysts of Isospora habiae Ortúzar-Ferreira & Berto n. sp. are subspheroidal to ovoidal, measuring on average 24 × 23 μm. A micropyle is absent. An oocyst residuum is present, whereas a polar granule is not observed. Sporocysts are ovoidal, with a mean size of 17 × 12 μm. Stieda and sub-Stieda bodies are present. A sporocyst residuum occurs among the vermiform sporozoites, which exhibit striations, refractile bodies, and a nucleus. This morphology clearly differs from that of other Isospora spp. previously recorded in hosts of the family Cardinalidae. Molecular identification was carried out through amplification and sequencing of three mitochondrial loci. In the molecular and phylogenetic analyses based on concatenated sequences of these loci, I. habiae n. sp. formed a monophyletic lineage and exhibited the highest similarity values with Isospora spp. infecting hosts of the families Cardinalidae and Sturnidae. Based on the combined morphological and molecular evidence obtained from oocysts recovered from H. rubica, I. habiae n. sp. is established here as new to science. It represents the third Isospora sp. documented from a cardinalid host and the first nominal species within this family to receive molecular characterization using mitochondrial gene sequences.

Systemic isosporosis (atoxoplasmosis) is a common disease of passerines globally. In July 2021, two free-ranging juvenile American robins (Turdus migratorius) from Kentucky, USA and a third of unknown age from Tennessee, USA died and were submitted to the Southeastern Cooperative Wildlife Disease Study for postmortem evaluation. On histopathology, high numbers of intracellular protozoal merozoites often associated with necrosis and granulomatous inflammation were observed in the lung (n = 2), liver (n = 2), spleen (n = 2), heart (n = 1), kidney (n = 1), and brain (n = 1). Isospora (Atoxoplasma) spp. was subsequently detected in all three birds. Comorbidities included poor nutritional condition (n = 3), traumatic injury (n = 1), avian pox (n = 1), aspergillosis (n = 1), and endoparasite infection (n = 1). Disease development in young robins is likely due to a combination of factors, including incompletely developed immune systems, nutritional and/or environmental stress, coinfections, and anthropogenic influences. Continued monitoring of vector-borne and parasitic diseases in wildlife is important given rapidly changing landscapes and climatic conditions.

Wild birds are important for public health, as they have epidemiological characteristics that make them host species for the transmission and maintenance of several pathogens, either as reservoirs or by the dispersal of infected arthropod vectors. Recently, several bird species have been used as model organisms in several scientific studies. Investigations have used wild bird populations as bioindicators and sentinels to identify changes in habitat quality, exposure to chemical pollutants, and disease surveillance. The objective of this study was to investigate the prevalence and diversity of parasites in birds in forest and anthropic areas of the Atlantic Forest in southeastern Brazil. The birds were captured between 2021 and 2023 using mist nets. Blood samples were obtained from each individual by brachial vein puncture to screen for hemoparasites. Fecal samples were collected to identify intestinal parasites. The overall prevalence of parasites in the study population was 44%, most of which came from the wild environment. Trypanosoma sp. was the most prevalent parasite in birds (34.6%), followed by Plasmodium sp. (18%) and the intestinal parasites microfilariae (9%), Cryptosporidium sp. (4.5%), Entamoeba sp. (4.5%), Giardia sp. (4.5%) and Isospora sp. (3%). All samples were negative for Toxoplasma gondii. The prevalence of parasites observed in this study was higher than that recorded in other studies conducted in the Neotropical Region and the Brazilian Atlantic Forest. Investigating parasites in birds provides valuable insights into understanding the epidemiology of various diseases and formulating prevention and control strategies. Due to their biological and ecological characteristics, birds act as important sentinels of the presence of infectious agents in ecosystems. In a global context of climate and environmental change, recognizing this role reinforces the importance of valuing their contributions and adopting effective conservation measures.

Ophidians host a wide range of pathogens, including many parasite species, some of which may be of public health concern because they can infect other animal species and humans. Herpetariums house snakes in captivity as part of ex-situ conservation initiatives aimed at preserving threatened species. However, stress, immunosuppression, and limited space increase the risk of parasitic infections, including zoonotic diseases. Here, we detect the presence of intestinal parasites in ophidian species housed under conditions of captivity. Twenty specimens representing sixteen species were examined using Teuscher's coproparasitological technique, which combines sedimentation and flotation for enhanced sensitivity. All snakes tested positive for at least one parasite species. Five taxa were identified: Oxyurid nematodes (Oxyurida) (50%), Isospora sp. (45%), Cryptosporidium sp. and Ophidascaris sp. (25% each), and Aspiculuris sp. (15%). Oxyurid sp. and Isospora sp. were the most prevalent parasite species, likely due to their direct life cycles. Although less frequent, Cryptosporidium sp. poses a significant health risk due to its potential morbidity in snakes. The presence of Aspiculuris, a parasite commonly found in rodents, suggests contamination from infected prey. These discoveries highlight the importance of implementing preventive veterinary care, routine parasitological monitoring, and improved biosecurity and feeding practices in captive snake populations. Finally, this study provides valuable data on parasite diversity in Mexican ophidians under human care.

Mitochondrial genomes of apicomplexan parasites exhibit remarkable structural diversity, ranging from highly reduced linear molecules to circular-mapping concatemers, yet their full characterization has been hindered by technical limitations in resolving complex infections. This study establishes a novel integrated workflow combining one-step PCR amplification with Oxford Nanopore Technologies (ONT) to sequence complete mitochondrial genomes from Eimeriidae and Haemosporida parasites. Successful assembly of 29 high-quality mitogenomes (12 Eimeriidae, 17 Haemosporida) from 15 samples, demonstrating the method's sensitivity. Comparative analyses revealed cryptic mixed/co-infections in 11 samples that were undetectable by Sanger sequencing, highlighting ONT's superior resolution for uncovering true parasite diversity. Phylogenomic reconstruction using the largest Eimeriidae dataset to date confirmed the monophyly of passeriform Isospora and identified a basal position for a novel Caryospora lineage from Ptyas major. In Haemosporida, analysis of 202 mitogenomes revealed non-monophyletic familial relationships. Selection analyses indicated predominant purifying selection in mitochondrial protein-coding genes of Eimeriidae. Our findings underscore the utility of long-read mitogenomics in elucidating complex infection dynamics and provide a scalable framework for biodiversity surveys of understudied apicomplexans parasites, with implications for understanding their evolutionary ecology and host-parasite interactions.