Sarcocystis sp.-Associated Meningoencephalitis in a Bald Eagle (Haliaeetus Leucocephalus)

Meningoencephalitis with malacia caused by Sarcocystis calchasi in a rock pigeon in Japan

Sarcocystis spp. cause pigeon protozoan encephalitis, a neuronal disease. A female pigeon exhibiting torticollis had a necrotic area in the cerebral hemisphere surrounded by lesions with perivascular cuffing, gliosis, granulomatous foci, and meningitis. Non-necrotic lesions were also observed in the brainstem. Intact and degenerative schizonts were observed within the neuropils and neurons in the lesions. Deoxyribonucleic acid (DNA) was extracted from paraffin-embedded brain tissues and genetically analyzed after gel electrophoresis to determine Sarcocystis spp. using specific primer sets for 28S ribosomal ribonucleic acid and internal transcribed spacer region-1. DNA sequencing confirmed a significant homology with S. calchasi. This is the first report of meningoencephalitis with malacia caused by S. calchasi in a rock pigeon in Japan.

Role of three bird species in the life cycle of two Sarcocystis spp. (Apicomplexa, Sarcocystidae) in the Czech Republic

Birds are one of the groups involved in the development of Sarcocystis Lankester (1882), serving either as intermediate or definitive hosts. The white-tailed sea eagle Haliaeetus albicilla (Linnaeus, 1758), red kite Milvus milvus (Linnaeus, 1758) (both Accipitriformes) and common starlings Sturnus vulgaris Linnaeus, 1758 (Passeriformes) were examined to elucidate their participation in the development of Sarcocystis, as well as to determine the specific identity of the parasites based on morphological and especially molecular analyses. In 2020-2021, one white-tailed eagle, one red kite and five common starlings were parasitologically examined for the presence of Sarcocystis using flotation centrifugation coprological method and by wet mounts of intestinal mucosa scrapings and/or muscle samples. Positive samples were processed by light microscopy, histologically and followed molecularly at four genetic markers (18S rRNA, 28S rRNA, ITS1 and cox1). The white-tailed eagle harboured oocysts/sporocysts of S. arctica Gjerde et Schulze, 2014 in the intestinal mucosa, while the intestinal mucosa of the red kite and breasts and leg muscles of one common starling were positive to S. halieti Gjerde, Vikøren et Hamnes, 2018. Sequences from eagle shared 99.6-100% identity with each other and S. arctica in the red fox (V. vulpes Linnaeus, 1758) from the Czech Republic. Sequences from the common starling and red kite shared 100% identity with each other and with S. halieti in the great cormorant (P. carbo [Linnaeus, 1758]) from Lithuania and H. albicilla from Norway. The white-tailed sea eagle might act as definitive host of S. arctica, whereas the common starling and red kite represent intermediate and potential definitive hosts, respectively, for S. halieti.

Molecular screening for Sarcocystidae in muscles of wild birds from Brazil suggests a plethora of intermediate hosts for Sarcocystis falcatula

The genus Sarcocystis and the species Toxoplasma gondii are the most prevalent sarcocystid organisms found in birds. Molecular phylogenies based on the first internal transcribed spacer of the ribosomal coding DNA (ITS1) have been widely used to identify them. Here, pectoral muscles from 400 wild birds from Brazil were screened by means of molecular methods using nested PCR, and Sanger sequencing yielded amplicons. A pan-sarcocystid ITS1-directed nested PCR revealed 28 birds infected by Sarcocystis falcatula (ten Piciformes, eight Psittaciformes, five Columbiformes, two Accipitriformes, one Anseriformes, one Passeriformes and one Strigiformes); one infected by Sarcocystis halieti (one Accipitriformes); nine infected by unknown or undescribed Sarcocystis (six Passeriformes, one Piciformes, one Cathartiformes and one Cuculiformes); and six harboring Toxoplasma gondii DNA (three Pelecaniformes, two Falconiformes and one Columbiformes). Samples harboring S. falcatula-related ITS1 sequences were further characterized by means of PCR and sequencing of genetic sequences of three surface antigen coding genes (SAGs). From this, 10 new allelic combinations of SAGs (SAG2, SAG3 and SAG4) were identified, in addition to 11 SAG allelic combinations already found in Brazil. Samples with S. falcatula-unrelated ITS1 sequences were further characterized by means of PCR and sequencing of cytochrome c oxidase subunit I coding sequences (CO1) and 18S ribosomal DNA gene (18S rDNA). This study was the first extensive survey of wild birds in Brazil for Sarcocystidae species. It provides the first molecular evidence of natural S. falcatula infection in 14 species, including in the order Piciformes, and shows the high genetic diversity of S. falcatula in intermediate hosts in South America. Evidence of occurrence of at least three non-described species of Sarcocystis was also presented in this study. This survey corroborated the ubiquity of T. gondii infection but revealed surprisingly low prevalence of this parasite (1.5%).

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Extensive survey of free-living wild birds in Brazil for Sarcocystidae species.

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Sarcocystis falcatula was detected in Piciformes birds for the first time.

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Sarcocystis falcatula has an extensive genetic diversity in Brazil.

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Three non-described species of Sarcocystis were detected.

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Sarcocystis halieti was detected for the first time in the Americas.

Sarcocystis calchasi and other Sarcocystidae detected in predatory birds in California, USA

Outbreaks of neurological disease associated with Sarcocystis calchasi have been observed in captive and free-ranging rock pigeons (Columba livia) in Europe and the United States as well as in wild Brandt's cormorants (Phalacrocorax penicillatus) and captive psittacines in California, USA. Experimental and field studies have identified northern goshawks (Accipiter gentilis) and European sparrowhawks (A. nisus) as definitive hosts in Europe while the definitive hosts elsewhere remain unknown. In this study, we aimed to identify the potential definitive host(s) of S. calchasi through molecular analysis of intestinal samples from seven predatory (n = 85) and one omnivorous (n = 11) bird species in California. In total, apicomplexan-generic 28S rRNA PCR products were obtained and sequenced for 42 raptors. Three of 16 (18.8%) Cooper's hawks (A. cooperii) and two of 26 (5.6%) red-tailed hawks (Buteo jamaicensis) also tested positive for the S. calchasi-specific ITS1 PCR and sequencing of the 28S rRNA PCR product was 100% homologous to S. calchasi. In addition to S. calchasi (5.9%; 5/85), other Sarcocystis spp. detected in raptors included: S. jamaicensis (21.2%; 18/85), S. columbae (8.2%; 7/85), S. turdusi (7.1%; 6/85), and S. halieti (4.7; 4/85%). Infections with closely related S. jamaicensis and S. (Frenkelia) microti (9.4%; 8/85) could not be distinguished for eight raptors. Eumonospora henryae (1.2%; 1/85) was detected in one raptor. Our results indicate for the first time that S. calchasi may have a definitive host range in North America that includes at least two raptors, Cooper's hawks and red-tailed hawks, within the family Accipitridae.

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Cooper's hawks and red-tailed hawks likely definitive hosts for Sarcocystis calchasi.

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Raptors may be infected with a diversity of closely related Sarcocystis spp.

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More research needed to clarify life cycles for bird-infecting Sarcocystis spp.

Protozoal encephalitis associated with Sarcocystis calchasi and S. falcatula during an epizootic involving Brandt's cormorants (Phalacrocorax penicillatus) in coastal Southern California, USA

Between March and May 2019, wildlife rehabilitation centers along coastal southern California admitted increased numbers of Brandt's cormorants (Phalacrocorax penicillatus) with neurological disease including head tilt, nystagmus, torticollis, tremors, paresis, paralysis, and ataxia. Seven cormorants from Los Angeles County and one cormorant from Orange County were submitted for postmortem examination. Gross findings included thin to fair body condition, generalized congestion/hyperemia, nematode parasites in the ventriculus, and diarrhea in the seven birds from Los Angeles County while the one bird from Orange County had icterus. Histologic examination revealed sarcocysts in the adductor muscles and meningoencephalitis characterized by coalescing infiltrations of macrophages, lymphocytes and plasma cells with severe perivascular cuffing and gliosis in all eight cormorants. Rare to few numbers of schizonts were seen in the cerebrum of the seven cormorants from Los Angeles County whereas the cormorant from Orange County had numerous schizonts in various stages of development in the cerebrum, cerebellum, and brainstem. All eight birds were positive for the generic Sarcocystis spp. 28S PCR. The seven cormorants from Los Angeles County tested positive for the S. calchasi-specific ITS1 and confirmed by sequencing, while the analysis of the 28S sequence in the cormorant from Orange County showed a 100% homology to S. falcatula. This bird also was positive by immunohistochemistry for Sarcocystis spp. using a polyclonal antibody that detects S. falcatula and S. neurona. This report demonstrates for the first time that seabirds such as Brandt's cormorants may be intermediate or dead-end hosts for S. calchasi and/or S. falcatula, and that S. calchasi can cause epizootic infection in a seabird.

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Neurological disease in Brandt's cormorants along southern California coast.

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Brandt's cormorants with protozoal encephalitis assocated with Sarcocystis spp.

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Brandt's cormorants may be intermediate hosts for S. calchasi and S. falcatula.

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Transmission of terrestrial protozoal pathogens to seabirds.

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Lifecycles of S. calchasi and S. falcatula in marine environment needs research.

An undescribed species of Sarcocystis associated with necrotizing meningoencephalitis in naturally infected backyard chickens in the Midwest of Brazil

Sarcocistys -associated menigoencephalitis is virtually an unrecognized cause of neurological disease in chickens. An undescribed species of Sarcocystis cause fatal infection in two backyard chickens in the Midwest of Brazil. Infected chickens presented anorexia, weight loss, incoordination, ataxia and opisthotonos. Yellow necrotic foci in the gray and white matter of the telencephalon were the main gross lesion. Microscopically, necrotizing granulomatous and heterophilic meningoencephalitis with intralesional Sarcocystis -like schizonts and mezoites were observed in the central nervous system. Molecular analysis of frozen brain samples of the two chickens was identical and the protozoan was named Sarcocystis sp. Chicken-2016-DF-BR. Complete nested PCR- sequence of Sarcocystis sp. Chicken-2016-DF-BR was equally similar to Sarcocystis anasi (EU553477) and Sarcocystis albifronsi (EU502868). This is the first report of Sarcocistys -associated meningoencephalitis with molecular characterization in backyard chickens.

Multidecade Mortality and a Homolog of Hepatitis C Virus in Bald Eagles (Haliaeetus leucocephalus), the National Bird of the USA

The bald eagle (Haliaeetus leucocephalus) once experienced near-extinction but has since rebounded. For decades, bald eagles near the Wisconsin River, USA, have experienced a lethal syndrome with characteristic clinical and pathological features but unknown etiology. Here, we describe a novel hepacivirus-like virus (Flaviviridae: Hepacivirus) identified during an investigation of Wisconsin River eagle syndrome (WRES). Bald eagle hepacivirus (BeHV) belongs to a divergent clade of avian viruses that share features with members of the genera Hepacivirus and Pegivirus. BeHV infected 31.9% of eagles spanning 4,254 km of the coterminous USA, with negative strand viral RNA demonstrating active replication in liver tissues. Eagles from Wisconsin were approximately 10-fold more likely to be infected than eagles from elsewhere. Eagle mitochondrial DNA sequences were homogeneous and geographically unstructured, likely reflecting a recent population bottleneck, whereas BeHV envelope gene sequences showed strong population genetic substructure and isolation by distance, suggesting localized transmission. Cophylogenetic analyses showed no congruity between eagles and their viruses, supporting horizontal rather than vertical transmission. These results expand our knowledge of the Flaviviridae, reveal a striking pattern of decoupled host/virus coevolution on a continental scale, and highlight knowledge gaps about health and conservation in even the most iconic of wildlife species.

Prevalence of Toxoplasma gondii, Neospora caninum, and Sarcocystis Species DNA in the Heart and Breast Muscles of Rock Pigeons (Columbia livia)

Little is known about the prevalence of protozoan parasites in the muscles of rock pigeons (Columbia livia). The muscles from 54 (heart from 45 and breast from 54) rock pigeons were examined for DNA of Toxoplasma gondii, Neospora caninum, and Sarcocystis species using PCR. Twenty-four were female and 30 were males. The birds were part of flocks of pigeons housed at the tombs of saints in Lahore, Pakistan. Birds that died or were euthanized due to poor health were submitted for necropsy at the Department of Parasitology, University of Veterinary and Animal Sciences, Lahore, Pakistan, where DNA isolations and PCR were conducted. Nineteen (35.1%) of the birds were positive for T. gondii DNA. Seven males and 12 females were positive. Breast tissue was always infected in T. gondii positive birds, while the heart was infected in 13 (28.8%) of breast positive birds. Five (9.2%) of the pigeons, 2 males and 3 females, were positive for N. caninum. The distribution of N. caninum DNA was more variable in the muscles of pigeons than T. gondii and was found only in the heart of 1 (female), heart and breast muscle of 2 (male), and only the breast muscle of 2 birds (female). One of the 54 rock pigeons (female) was positive for both T. gondii (heart and breast) and N. caninum (heart only). Two of the positive Neospora caninum amplicons were sequenced and had 97% nucleotide identity with N. caninum isolates. Sarcocystis DNA was not found in any bird. The prevalence of T. gondii in rock pigeons and their predation by cats suggest that they may play an unrecognized role in maintaining environmental contamination with T. gondii oocysts by cats. Our study indicates that rock pigeons are intermediate hosts of N. caninum and this information will aid in understanding the epidemiology of N. caninum.

Molecular identification of Sarcocystis halieti n. sp., Sarcocystis lari and Sarcocystis truncata in the intestine of a white-tailed sea eagle (Haliaeetus albicilla) in Norway

An emaciated white-tailed sea eagle (Haliaeetus albicilla) from Western Norway was found and nursed briefly before it died. The necropsy revealed that the principal cause of death was an inflammation and occlusion of the bile ducts. A secondary finding was the presence in the intestinal mucosa of numerous sporulated Sarcocystis oocysts measuring 21.8-22.8 × 16.0-17.0 μm. The aim of this study was to identify these oocysts to species level using molecular methods. Genomic DNA was extracted from 10 mucosal scrapings containing oocysts and subjected to PCR amplification and sequencing of four DNA regions: the 18S and 28S rRNA genes, the ITS1 region and the cox1 gene. DNA of three previously known Sarcocystis spp. was identified, but only two of these, Sarcocystis halieti n. sp. and Sarcocystis lari, both employing sea birds as intermediate hosts, were considered to have used the sea eagle as a definitive host and to have formed oocysts in its intestine. The third species found, Sarcocystis truncata, employs red deer as intermediate hosts and seems to use felids as definitive hosts based on its phylogenetic position and prevalence. The sea eagle had probably recently ingested portions of one of the latter hosts (red deer or cat/lynx) containing stages (sarcocysts/oocysts) and thus DNA of S. truncata. The species S. halieti and S. lari could only be unambiguously separated from their most closely related congeners on the basis of their ITS1 sequences. This is the first report of Sarcocystis oocysts in sea eagles and the first identification to species level of Sarcocystis oocysts in any type of eagle. The sea eagle also acted as intermediate host of an unidentified Sarcocystis spp. as evidenced by the finding of six thin-walled sarcocysts in a histological section of cardiac muscle.

A RETROSPECTIVE SUMMARY OF RAPTOR MORTALITY IN ONTARIO, CANADA (1991-2014), INCLUDING THE EFFECTS OF WEST NILE VIRUS

The causes of mortality of free-ranging raptors range from anthropogenic (e.g., trauma) to dynamic environmental conditions that may affect habitat suitability and prey availability. The province of Ontario, Canada, is vulnerable to anthropogenic and environmental changes because of its northern latitudes and expanding human populations, both of which may impact wildlife. We retrospectively evaluated diagnostic data from raptors submitted to the Ontario/Nunavut node of the Canadian Wildlife Health Cooperative (CWHC) from 1991 to 2014 ( n=1,448). Submissions encompassed 29 species, most commonly the Red-tailed Hawk ( Buteo jamaicensis; n=308) and Great Horned Owl ( Bubo virginianus; n=237). Trauma ( n=716) accounted for the majority of deaths among all species, followed by emaciation ( n=241). Traumatic deaths were most commonly attributed to collisions with stationary objects, and the odds of a diagnosis of trauma were significantly higher in adult versus immature raptors. The odds of being diagnosed with emaciation were significantly higher in males than in females but not in any age class or season. Mortality was less commonly attributed to infectious diseases ( n=214), for which West Nile virus (WNV) was the most common etiology, making up 53.1% of infectious diagnoses after its 2001 arrival in Ontario. The odds of a raptor being diagnosed with an infectious disease were significantly greater in summer and fall versus spring. Immature Red-tailed Hawks had significantly greater odds of being diagnosed with WNV compared to adults. These results reveal that human- and potentially environmentally-associated deaths (e.g., trauma and emaciation, respectively) are commonly diagnosed among Ontario raptors submitted to the CWHC. Infectious diseases are less commonly diagnosed, but WNV may have underlying, ongoing impacts on the health of some raptor species.

Acute, fatal Sarcocystis calchasi-associated hepatitis in Roller pigeons (Columba livia f. dom.) at Philadelphia Zoo

Four Roller pigeons (Columba livia f. dom.) at the Philadelphia Zoo died suddenly. Necropsy examination revealed macroscopic hepatitis. Microscopically, the predominant lesions were in liver, characterized with necrosis and mixed cell inflammatory response. Sarcocystis calchasi-like schizonts and free merozoites were identified in liver. Transmission electron microscopy confirmed that schizonts were in hepatocytes. A few schizonts were in spleen. PCR using S. calchasi-specific primers confirmed the diagnosis. Neither lesions nor protozoa were found in brain and muscles. This is the first report of acute visceral S. calchasi-associated sarcocystosis in naturally infected avian hosts.

An update on Sarcocystis neurona infections in animals and equine protozoal myeloencephalitis (EPM)

Equine protozoal myeloencephalitis (EPM) is a serious disease of horses, and its management continues to be a challenge for veterinarians. The protozoan Sarcocystis neurona is most commonly associated with EPM. S. neurona has emerged as a common cause of mortality in marine mammals, especially sea otters (Enhydra lutris). EPM-like illness has also been recorded in several other mammals, including domestic dogs and cats. This paper updates S. neurona and EPM information from the last 15 years on the advances regarding life cycle, molecular biology, epidemiology, clinical signs, diagnosis, treatment and control.

A new species of Caryospora (Apicomplexa: Eimeriidae) from the bald eagle, Haliaeetus leucocephalus (Accipitriformes: Accipitridae), from Kansas

Between March 1989 and February 1994, 4 bald eagles ( Haliaeetus leucocephalus ) from various localities in Kansas were examined for coccidia. One (25%) of the bald eagles was found to be passing an undescribed species of Caryospora in its feces. Oocysts of Caryospora hanebrinki n. sp. are ellipsoidal to ovoidal with a bilayered wall and measure 48.1 × 42.1 μm with a shape index of 1.2. A micropyle, oocyst residuum, and polar granule were absent. Sporocysts are spheroidal, 24.8 μm wide. Stieda, substieda, and parastieda bodies were absent; a spheroidal sporocyst residuum is present; it measures 17.5 μm and is composed of many intact homogenous globules with a few dispersed in a loose spiral around the sporocysts. This is the first caryosporan documented from the bald eagle and is the largest known Caryospora from raptors.

Natural Fatal Sarcocystis Falcatula Infections in Free-Ranging Eagles in North America

Three bald eagles ( Haliaeetus leucocephalus) and 1 golden eagle ( Aquila chrysaetos) were admitted to rehabilitation facilities with emaciation, lethargy, and an inability to fly. Intravascular schizonts and merozoites were present in 2 bald eagles, mainly in the lung tissue, whereas the third bald eagle and the golden eagle had lymphohistiocytic encephalitis with intralesional schizonts and merozoites. In all eagles, protozoal tissue cysts were present in skeletal musculature or heart. The protozoal organisms were morphologically compatible with a Sarcocystis sp. By immunohistochemistry, the protozoal merozoites were positive for Sarcocystis falcatula antigen in all cases when using polyclonal antisera. Furthermore, the protozoa were confirmed to be most similar to S. falcatula by polymerase chain reaction in 3 of the 4 cases. To the authors' knowledge, this report presents the first cases of natural infection in eagles with S. falcatula as a cause of mortality.