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The apicomplexan parasite Sarcocystis calchasi (Coccidia: Eimeriorina: Sarcocystidae) is the causative agent of Pigeon Protozoal Encephalitis (PPE) and infects birds of the orders Columbiformes, Piciformes and Psittaciformes. Accipiter hawks (Aves: Accipitriformes) are the definitive hosts of this parasite. Infections of S. calchasi have been detected in Germany, the United States and Japan. However, the prevalence of the parasite in racing pigeon flocks has not yet been determined. Here, the first cross-sectional prevalence study to investigate S. calchasi in pigeon racing flocks was accomplished including 245 pigeon flocks across Germany. A total of 1,225 muscle biopsies, were taken between 2012 and 2016 and examined by semi-nested PCR for S. calchasi DNA targeting the ITS gene. Additionally, a questionnaire on construction of the aviary as well as management and health status of the flock was conducted. In 27.8% (95% C.I. = 22.3-33.8%) of the flocks, S. calchasi DNA was detected in at least one pigeon. Positive flocks were located in 15 out of 16 federal states. A significant increase of infected racing pigeons was seen in spring. Half-covered or open aviary constructions showed a trend of increase of the prevalence rate, while anti-coccidian treatment and acidified drinking water had no effects. The high prevalence and the geographical distribution of S. calchasi suggest a long-standing occurrence of the parasite in the German racing pigeon population. For pigeons presented with neurological signs or other symptoms possibly related to PPE, S. calchasi should be considered as a potential cause throughout Germany., Competing Interests: The authors have declared that no competing interests exist.

The apicomplexan parasite Sarcocystis calchasi (S. calchasi) triggers pigeon protozoal encephalitis, a neurologic disease in columbids. Accipiter hawks have been identified as the final host, and Columbidae and Psittaciformes as intermediate hosts. In this study, 368 free-ranging Accipiter hawks and 647 free-ranging common woodpigeons were sampled in a country-wide study in order to identify the prevalence of S. calchasi in these populations. A semi-nested PCR specific for S. calchasi tested positive in 7.3% (4.9-10.5) of submitted samples from Accipiter hawks. Juvenile Accipiter hawks (13.7%; 7.7-22.0) had a significantly higher infection rate with S. calchasi than adult Accipiter hawks (5.8%; 2.7-9.3). The prevalence of S. calchasi in common woodpigeons was 3.3% (5.4-9.7). Positive pigeons were identified in 14/16 federal states, and a region-dependency was detected, with higher rates of infection in the eastern parts of Germany. The results of this study suggest that the common woodpigeon is a natural reservoir for S. calchasi. In a study of one region for four consecutive years, an increase in prevalence was not detected. Findings indicate that the parasite is not newly introduced to Germany, but rather long established. The prevalence suggests that there is a substantial risk of S. calchasi infections in other free-ranging as well as captive host species.

Between June and November 2015, 25 woodpeckers (Picidae) with neurologic signs or unknown cause of death were admitted to a veterinary clinic. Alive birds were clinically examined. Birds that were found dead or died despite intensive care treatment were forwarded to a pathologic examination. Necropsy and subsequent tests included screening for several infectious agents and toxins. Three birds tested positive for Sarcocystis calchasi. Toxoplasma gondii was detected in one bird demonstrating intracerebral cysts. Mycoplasma gypis was detected in one woodpecker in the absence of respiratory signs. Several microbial pathogens (eg, Aspergillus fumigatus, Clostridium perfringens, and Escherichia coli) were isolated from single individuals. However, there was no consistent finding in all birds that could explain nervous signs and mortality of the woodpeckers examined. To the authors' knowledge, M. gypis and S. calchasi were detected in a woodpecker for the first time in this study.

In May 2014, six patients presented in Germany with a Sarcocystis-associated febrile myositis syndrome after returning from Tioman Island, Malaysia. During two earlier waves of infections, in 2011 and 2012, about 100 travellers returning to various European countries from the island were affected. While the first two waves were associated with travel to Tioman Island mostly during the summer months, this current series of infections is associated with travel in early spring, possibly indicating an upcoming new epidemic.

Sarcocystis spp. represent apicomplexan parasites. They usually have a heteroxenous life cycle. Around 200 species have been described, affecting a wide range of animals worldwide, including reptiles. In recent years, large numbers of reptiles have been imported into Europe as pets and, as a consequence, animal welfare and species protection issues emerged. A sample of pooled feces from four confiscated green pythons (Morelia viridis) containing Sarcocystis spp. sporocysts was investigated. These snakes were imported for the pet trade and declared as being captive-bred. Full length 18S rRNA genes were amplified, cloned into plasmids and sequenced. Two different Sarcocystis spp. sequences were identified and registered as Sarcocystis sp. from M. viridis in GenBank. Both showed a 95-97% sequence identity with the 18S rRNA gene of Sarcocystis singaporensis. Phylogenetic analysis positioned these sequences together with other Sarcocystis spp. from snakes and rodents as definitive and intermediate hosts (IH), respectively. Sequence data and also the results of clinical and parasitological examinations suggest that the snakes were definitive hosts for Sarcocystis spp. that circulate in wild IH. Thus, it seems unlikely that the infected snakes had been legally bred. Our research shows that information on the infection of snakes with Sarcocystis spp. may be used to assess compliance with regulations on the trade with wildlife species.

The emerging Sarcocystis calchasi induces a severe and lethal central nervous disease in its intermediate host, the domestic pigeon (Columba livia f. domestica). Experimental studies have identified the Northern goshawk (Accipiter g. gentilis) as final host. Phylogenetically closely related European sparrowhawks (Accipiter n. nisus) and wood pigeons (Columba palumbus) have been found to harbor genetically closely related Sarcocystis spp. However, data on the prevalence and potential interspecies occurrence of these parasites are lacking. Here, we report that European Accipiter hawks (Accipitrinae) are highly infected with S. calchasi, S. columbae and Sarcocystis sp. ex A. nisus in their small intestine. Thirty-one of 50 (62%) Northern goshawks necropsied during 1997-2008 were positive for S. calchasi in a newly established species-specific semi-nested PCR assay based on the first internal transcribed spacer region. Unexpectedly, 14 of 20 (71.4%) European sparrowhawks tested also positive. In addition, birds of both species were found to be infested with S. columbae and an, as yet, unnamed Sarcocystis sp. recently isolated from European sparrowhawks. These findings raise new questions about the host specificity of S. calchasi and its high virulence in domestic pigeons, since sparrowhawks only rarely prey on pigeons. Notably, isolated sporocysts from both infected Accipiter spp. measured 8 μm × 11.9 μm, precluding a preliminary identification of S. calchasi in feces of Accipiter hawks based on morphology alone. Importantly, three of four Northern goshawks used in falconry tested positive for S. calchasi. In conclusion, the results indicate that both European Accipter spp. in Germany serve as natural final hosts of S. calchasi and suggest that falconry and pigeon sport may serve as risk factors for the spread of this pathogen in domestic pigeons., (Copyright © 2010 Elsevier B.V. All rights reserved.)

A large number of Sarcocystis spp. infect birds as intermediate hosts, but pigeons are rarely affected. We identified a novel Sarcocystis sp. that causes lethal neurologic disease in domestic pigeons in Germany. Experimental infections indicated transmission by northern goshawks, and sequence analyses indicated transnational distribution. Worldwide spread is possible.

Four different forms of sarcocysts from the zoo-kept antelopes Addax nasomaculatus. Antilope cervicapra, Taurotragus oryx and Boselaphus tragocamelus (Bovidae) were investigated by light and transmission electron microscopy, in special consideration of the cyst wall. The sarcocysts found in Addax (born in a zoo) were not distinguishable from Sarcocystis medusiformis of Australasian sheep by their morphology and would be the first indication for the occurrence of this species in Europe. Sarcocysts from Antilope (born in a zoo) resembled the tenella/capracanis type of sheep/goats and were, therefore, designated as Sarcocystis sp. (? cf. capracanis) in this paper. Sarcocysts from Taurotragus were similar to a zoonotic species of cattle and hence provisionally designated as S. sp. (? cf. hominis). A sarcocyst form with hair-like villar protrusions of the cyst wall was found in Taurotragus. Boselaphus and Antilope and compared with a common species of cattle: S (? cf. cruzi).

Sarcocysts from the musculature of a dwarf zebu born in a German zoo are described by light and transmission electron microscopy. In addition to the three named bovine Sarcocystis species (Sarcocystis cruzi, S. hominis, and S. hirsuta) a fourth species was found which was not previously reported from cattle. It mostly resembles Sarcocystis gracilis Rátz, 1909 from roe deer.

Three species of sarcocysts from European roe deer (Capreolus capreolus) are characterised using light and electron microscopy. The hitherto existing descriptions of four species are attributed to the actual state of nomenclature.

Sarocysts were found in muscle tissue of a wisent (Bison bonasus) which was born and kept in Germany. Light microscopic and TEM examination revealed all the three named species known from cattle: Sarcocystis cruzi ("thin-walled", with longer hair-like villar protrusions of the primary cyst wall); S. hirsuta ("thick-walled", with tongue-like protrusions of the cyst wall arising with very short and narrow stalklets from the surface of the cyst and containing rows of electron-dense granules in the core); and S. hominis ("thick-walled", with finger-like protrusions of the cyst wall not constricted at their base and containing few or no electron-dense granules). So far, only S. cruzi was known to occur in Bison bison in North America. The findings in the wisent strikingly support a modified conception of the intermediate host specificity in Bovinae. In this connection the identity of S. cruzi and S. poephagicanis is suggested as well as that of S. hirsuta and S. poephagi.