Prevalence of Caryospora Species (Apicomplexa: Eimeriidae) in Falcons in the United Arab Emirates

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.

Prevalence of Caryospora (Apicomplexa: Eimeriidae) Oocysts in the Environment of a Gyrfalcon (Falco rusticolus) Breeding Center in the United Arab Emirates

A total of 356 gyrfalcon (Falco rusticolus) fecal, fomite, and environmental samples were collected from a breeding center located in the United Arab Emirates to assess the prevalence of Caryospora species oocysts in the environment. These included 136 samples (38%) from fomites and fecal samples from chicks at 0 to 10 days old, 29 samples (8%) at 15 days old, 23 samples (6%) at 60 days old, 7 samples (2%) at 67 days old, and 24 samples (7%) at 70 days old. In addition, 105 samples (29%) were collected from the environment of 13 breeding chambers, and 32 samples (9%) from the environment of 17 juvenile falcons. The prevalence of Caryospora species oocysts in fomites and fecal samples from the chicks had negative results from 10 to 60 days old. However, at 67 and 70 days old, the prevalence increased to 71.42% (5 of 7) and 95.83% (23 of 24), respectively. The prevalence of Caryospora species in the environment of 13 pairs of falcons housed in 13 breeding chambers was 0.15 oocyst/m² in the sand, whereas, in the environment of 17 juvenile falcons housed in the free-flying aviary, the prevalence was 0.00086 oocyst/m² in the sand and 0.15 oocyst/L in contaminated water. These results indicate that oocysts of Caryospora species may be found in the environment and in areas of poor and substandard hygiene. Caryospora species is an important protozoon parasite affecting captive falcons maintained in breeding centers and those used for falconry in the Middle East.

Detection of Eumonospora henryae (Apicomplexa: Sarcocystidae) from Falco columbarius (Falconiformes: Aves): Comparison of host-parasite phylogram and comments on the family Sarcocystidae Poche, 1913

The genus Eumonospora Allen, 1933 (Apicomplexa: Sarcocystidae), an avian coccidia, is characterized by monosporocystic and octasporozoic oocysts without Stieda and substieda bodies. Some members of Eumonospora, which infect several raptor species, exhibit high levels of pathogenicity, making eumonosporiosis the leading cause of death in captive-bred raptors. The host specificity of these species appears to be mesostenoxenous, as evidenced by unsuccessful transmission between different orders of avian hosts. However, several studies have detected Eumonospora spp. in taxonomically distant avian hosts, indicating that some of these species may be euryxenous. In the current study, diarrheic fecal examination of a captive-bred juvenile merlin (Falconiformes: Aves) in Tokyo, Japan, was conducted, and a large number of oocysts were morphologically and molecularly identified as E. henryae (Yakimoff and Matschulsky, 1932), a coccidia species reported only in Strigiformes. This is a new recorded host for this coccidia. Phylogenetic analyses via Bayesian inference and maximum likelihood methods using concatenated genomic datasets consisting of nuclear 18S rDNA, nuclear 28S rDNA and mitochondrial cytochrome C oxidase subunit 1 gene, revealed a well-supported monophyletic clade of Eumonospora spp. belonging to the family Sarcocystidae Poche 1913, which largely corresponded to the avian host phylogram. Therefore, based on distinguishable oocyst morphology, a new subfamily, Eumonosporinae, within the family Sarcocystidae, is proposed, and a reconsideration of the definition of Sarcocystidae is suggested. Further molecular characterization of this emerging pathogen, as well as clarification of its complete life cycle, including cyst-forming ability, is required for more appropriate generic assessment.

The emergence of Caryospora neofalconis in falcons in Central Saudi Arabia

Objective:

This study aimed to examine the occurrence of Caryospora (C.) neofalconis in falcons from the central region of the Kingdom of Saudi Arabia (KSA).

Materials and methods:

Fecal samples (n = 149) from 149 healthy falcons including 56 saker falcons (Falco cherrug), 13 lanner falcons (F. biarmicus), 18 peregrine falcons (F. peregrinus), 40 Barbary falcons (F. pelegrinoides), and 22 gyrfalcons (F. rusticolus) were collected between October 2018 and May 2019. The fecal samples were examined for the presence of C. neofalconis by microscopic examination followed by confirmation by polymerase chain reaction targeting 18S rRNA genes and their phylogenetic analyses.

Results:

The overall prevalence of C. neofalconis in the falcons was recorded as 10.7% (16/149) by microscopic examination. The highest prevalence was found in F. peregrinus (6/18, 33.3%), followed by F. rusticolus (3/22, 13.6%), F. cherrug (5/56, 8.9 %) and F. pelegrinoides (2/40, 5.0%). There was no C. neofalconis infection observed in F. biamicus. The 18S rRNA gene could be amplified in eight samples. The phylogenetic analysis of two C. neofalconis isolates exhibited a close relationship with the Mexican isolate (KT03081) with a 99.7% identity.

Conclusion:

To our knowledge, based on the microscopic and molecular analysis, this is the first report of C. neofalconis in F. cherrug, F. rusticolus, F. pelegrinoides, and F. peregrinus from the central region of the KSA and it emphasize the value of adopting preventive measures to limit the spread of C. neofalconis.

Molecular and morphological analysis of a Caryospora-like isolate (Apicomplexa: Eimeriidae) from the magpie-lark (Grallina cyanoleuca) (Latham, 1801) in Western Australia

A new Caryospora-like isolate is described from a magpie-lark (Grallina cyanoleuca) in Western Australia. Sporulated oocysts of the Caryospora-like isolate (n = 35) are subspherical with a shape index of 1.13 ((21.5 (19.7-23.6) × 19.0 (18.1-19.8) μm). The bilayered oocyst wall is smooth. Micropyle, polar granule and oocyst residuum are absent. The sporocyst is ellipsoidal, 18.9 (17.2-20.8) × 12.3 (11.9-12.8) μm, with a shape index (length/width) of 1.54. The sporocyst wall is bilayered. Stieda and substieda bodies are present, the Stieda body is small and flattened and the substieda is trapezoidal. Sporocyst with eight sporozoites arranged head to tail. The sporozoites are vermiform, 18.9 (17.2-20.8) × 12.3 (11.9-12.8) μm and have striations at the anterior end. Each sporozoite has both anterior and posterior refractile bodies. A sporocyst residuum is present. Molecular characterization of the isolated Caryospora-like oocysts was conducted at the 18S ribosomal RNA and the mitochondrial cytochrome oxidase (COI) loci. At the 18S rRNA locus, the Caryospora-like isolate exhibited 88.8% to 96.5% similarity with other Caryospora spp. from different hosts. At the COI locus, it showed 91.5% similarity to Caryospora cf. bigenetica JB-2013 (KF859856) from the rattlesnake, Sistrurus catenatus.