Unusual Biphasic Disease In Domestic Pigeons Biology Essay

A new Sarcocystis species has late been reported in the domestic pigeon ( Columba livia f. domestica ) as intermediate host, doing terrible cardinal nervous marks similar to Paramyxovirus-1 or Salmonella typhimurium volt-ampere. bull. infection. Transmission of the parasite via the Northern Accipiter gentilis ( Accipiter gentilis ) as unequivocal host has been established. Experimental infection of domestic pigeons with sporocysts excreted by by experimentation septic Northern Accipiter gentilis reproduced the natural infection in the pigeon, turn outing the causative function of the parasite in the disease. Here, we describe the class of a fulminant biphasic disease depending on the infective dosage. Pigeons infected with 103 and 104 sporocysts showed clinical marks of polyuria and apathy as a first stage 10 to 11 dpi and sudden neurological marks 51 to 57 dpi as a 2nd stage. Pigeons infected with higher doses died within 7 to 12 dpi besides demoing polyuria and apathy. At autopsy, liver and lien had multifocal necroses and infestations with schizonts. Pigeons infected with 102 sporocysts kept symptomless until 58 to 65 dpi, when sudden cardinal nervous marks occurred. Major histopathologic findings of pigeons with neurological marks were encephalitis and myositis of the skeletal musculuss with high infestations of sarcocysts. By contrast, in the same experiment, poulets failed to develop any clinical marks or diseased lesions. In decision we

Worldwide, a big figure of Sarcocystis species ( Protozoa: Apicomplexa ) have antecedently been reported to infect avian species but have merely on occasion been described in Columbiformes ( Olias et al. , 2009c ) . Some avian Sarcocystis species such as Sarcocystis neurona and Sarcocystis falcatula are known for their assortment of natural and deviant host species. S. neurona causes neurological disease in a wide scope of animate beings, including domestic Equus caballuss, Canis familiariss, cats, raccoons, rotters, minks and Rhesus monkeys ( Klumpp et al. , 1994 ; Dubey et al. , 2001 ; Dubey et al. , 2003 ; Dubey et al. , 2006 ) . S. falcatula, which is transmitted by the North American phalanger ( Didelphis virginiana ) , has been shown to be infective for domestic pigeons but merely in experimental infective surveies ( Box & A ; Smith, 1982 ) . Among the really few species of course infecting domestic domestic fowl are Sarcocystis horvathi and Sarcoystis wenzeli which cyle between poulets ( Gallus gallus ) as intermediate host and Canis familiariss ( Canis lupus ) as unequivocal host, whereas S. wenzeli besides uses cats ( Felis catus ) as alternate unequivocal host ( Wenzel et al. , 1982 ) . Sarcocystis rileyi utilizations ducks as intermediate host and rotters ( Mephitis mephitis ) as unequivocal host ( Riley, 1931 ) .

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We late reported a fresh neurologic disease with deadly result in domestic pigeons ( Columba livia f. domestica ) in Berlin, Germany, caused by a so far unknown Sarcocystis species ( Olias et al. , 2009a ) . Clinical marks, really similar to those caused by Paramyxovirus-1 or Salmonella typhimurium volt-ampere. cop. , included apathy, polyuria, wryneck, opisthotonus, palsy, trembling and decease. Pigeons had parasitic cysts in their musculuss and evidently function as intermediate hosts in a two-host life rhythm characteristic for Sarcocystis, in which intermediate hosts ( quarry ) are infected by consumption of sporocysts shed with the fecal matters by the unequivocal host ( marauder ) ( Mehlhorn & A ; Heydorn, 1978 ; Dubey, 1989 ) . The unequivocal host of this new Sarcocystis species was hence hypothesized to be a typical pigeon marauder, holding regular contact to domestic pigeons. Experimental infective surveies of Canis familiariss ( Canis familaris, beagle ) , Mustela nigripess ( Mustela putorius furo ) , rats ( Rattus norvegicus f. domestica ) , mice ( Mus musculus domesticus ) , Northern goshawks ( Accipiter gentilis ) and Gyr-saker ( Falco rusticolus A- Falco cherrug ) intercrossed falcons identified the Northern Accipiter gentilis as unequivocal host, casting high Numberss of sporocysts in the fecal matters ( Olias et al. , 2009b ) . Subsequent experimental infections of domestic pigeons with goshawk-derived and purified sporocysts clearly reproduced the natural disease and determined the causative function of the parasite, so named Sarcocystis calchasi, in this fresh disease in pigeons ( Olias et al. , 2009c ) .

Here, we further depict the clinical class of the disease in the pigeons after experimental infection with S. calchasi. Further experimental infective surveies were conducted to prove poulets ( Gallus gallus ) as alternate intermediate hosts of the parasite.

Material and Methods


As intermediate and possible intermediate hosts 17 grownup domestic pigeons ( Columba livia f. domestica ) and 10 5-week-old SPF-chicken ( Gallus gallus f. domestica ; Valo, Lohmann, Germany ) were used in this survey. Biopsies of thoracic musculus of all birds had no parasitic constructions prior to the experiment. The animate beings were examined 14 yearss prior to infection and were clinically healthy. Faecal scrutiny confirmed absence of Salmonella species and entoparasites.

Beginning of Sarcocystis Sporocysts

The Sarcocystis species used for experimental infection was derived from the little bowel of one Northern Accipiter gentilis ( Olias et al. , 2009b ) by experimentation infected with of course cyst-infested thoracic musculus of a rushing pigeon from a recent eruption in Berlin, Germany in 2008 ( Olias et al. , 2009a ) .

Experimental Infection

Sporocysts were purified and counted as described elsewhere ( Rommel et al. , 1995 ) . Sixteen pigeons were separated in eight groups of two birds each ; one extra pigeon was housed in group 1 as lookout animate being. Infectious doses of sporocysts for the pigeons were 3 A- 106 sporocysts ( group 1 ) ; 3 A- 105 ( group 2 ) ; 105 ( group 3 ) ; 104 on eight back-to-back yearss ( 104 A- 8 ; group 4 ) ; 104 ( group 5 ) ; 103 ( group 6 ) and 102 ( group 7 ) . Pigeons of group 8 served as control animate beings. Sporocysts suspended in 2 milliliter unfertile H2O were administered straight into the harvest. The lookout pigeon and the birds of the control group received merely 2 milliliter of unfertile H2O ( table 1 ) . The poulets were housed together in a standardised isolator. Two control chickens received 2 milliliters of unfertile H2O and two poulets each a dosage of 102, 104, 3 A- 105 or 3 A- 106 sporocysts, severally. All pigeons and poulets were observed four times daily during the full class of the experiment. Animals with neurological marks were euthanized. Surviving pigeons were euthanized 59 and 120 dpi, severally. Chickens were euthanized 59 dpi. All experiments were performed under governmental blessing ( No. Reg 0111/08 ) .

Gross and Histopathologic Examination

A complete autopsy was performed on all pigeons and poulets. Tissue samples from the tegument, skeletal musculus ( thoracic, gastrocnemius and cervix musculuss ) , bone marrow, unwritten pit, oesophagus, harvest, lung, bosom, liver, pancreas, lien, kidneys, proventriculus, gizzard, bowel and encephalon were fixed in phosphate-buffered formol and processed as described above.

Faecal Examination and Microbiology

After infection, faecal stuff of pigeons and poulets was tested twice daily between the 1st and 7th dpi for sporocysts utilizing floatation with concentrated Na chloride solution ( Rommel et al. , 1995 ) . For sensing of Salmonella and Paramyxovirus, liver, intestine, lung, encephalon, kidney and spleen samples from all pigeons were analysed as described ( Olias et al. , 2009a ) .

Designation of Parasites

For molecular sensing of the D2 part of the 28S rRNA cistron and word picture of potentially developed musculus cysts, 25 milligram of thoracic musculus and liver of each pigeon was minced into little pieces and further processed for PCR as described above.


Clinical Signs

Pigeons of groups 1 to 4 ( 3 A- 106 to 8 A- 104 sporocysts ) died within 12 dpi with terrible apathy and polyuria ( table 1 ; figure 1, 3A ) . The lookout pigeon kept in group 1 developed mild apathy and polyuria 13 dpi but clinical marks of this animate being resolved after three yearss. Pigeons of groups 5 and 6 ( 104 to 103 sporocysts ) developed a biphasic disease with mild to chair apathy and polyuria about 10 dpi, with marks deciding 12-18 dpi as a first stage. Eight hebdomads after infection, pigeons of group 5 developed terrible and pigeons of group 6 moderate neurological marks including wryneck, opisthotonus, trembling and palsy as the 2nd stage of the disease ( figure 2 ) . Pigeons of group 7 infected with 102 sporocysts had mild to chair neurological marks 57 to 64 dpi without earlier clinical marks. Control pigeons of group 8 remained healthy throughout the full test. None of the poulets developed any clinical marks.

Faecal Examination and Microbiology

Pigeons did non shed parasites in their fecal matters at any clip. No Salmonella spp. were cultured and no hemagglutinating agent was detected in all samples examined.

Pathological and Histopathological Lesions after Infection

At autopsy, pigeons of group 1 to 4 that died 7 to 12 dpi ( first stage ) had enlarged, discoloured livers with multifocal to blending necroses ( figures 3 ) . Two pigeons to boot showed a terrible diffuse, fibrinous perihepatitis. Microscopically, livers and liens had multifocal necroses and chair to severe infiltration with lymph cells, plasma cells and macrophages ( figures 4B, C ; table 1 ) . Merely a few pigeons had mortification and redness in the lungs, kidneys, bone marrows and connective tissues of several variety meats next to blood vass. Parasitic phases were preponderantly observed in the liver, spleen and in or following to endothelial cells of several other variety meats ( figures 4C, D ; table 1 ) . Pigeons of group 5 to 7 and the lookout pigeon kept in group 1 that were euthanized 51 to 65 dpi ( 2nd stage ) had marked phrenitis, myositis and Sarcocystis cysts in all skeletal musculuss examined ( thoracic, gastrocnemius and cervix musculuss ) . Both control pigeons of group 8 had no gross or microscopical lesions. None of the poulets had any gross or histological lesions.

Sequence Analysis

Comparison of the D2 part of the 28S rRNA cistron revealed indistinguishable cistron sequences of cysts in the skeletal musculus of the by experimentation septic pigeons compared to the sporocysts from the Northern Accipiter gentilis and the cysts of the of course septic pigeons ( Olias et al. , 2009a ) .


The lifecycle of a new Sarcocystis species named S. calchasi has antecedently been described to include the Northern Accipiter gentilis ( Accipiter gentilis ) as unequivocal ( concluding ) host and the domestic pigeon ( Columba livia f. domestica ) as intermediate host ( Olias et al. , 2009b, degree Celsius ) . Oral disposal with different doses of sporocysts of the parasite confirmed that domestic pigeons are extremely susceptible as intermediate hosts. The character and badness of clinical marks varied, depending on the infective dosage and propose a biphasic class of the disease.

Clinically, affected pigeons developed apathy and polyuria within 6 to 12 dpi of which pigeons of groups 1 to 4 infected with high doses died. Lone pigeons infected with 102 sporocysts ( group 7 ) developed no clinical marks in this first stage of the disease ( figure 1 ) . Histopathology and electron microscopy of asleep pigeons revealed many schizonts in all developmental phases to be chiefly located in the liver and in or following to endothelial cells in several other variety meats associated with a moderate to severe inflammatory response. All lasting pigeons ( groups 5 to 7 ) all of a sudden developed chair to terrible cardinal nervous marks 51 to 65 dpi as a 2nd stage. Histopathology of the encephalon and the musculus tissue revealed indistinguishable lesions when compared to antecedently described of course septic pigeons ( Olias et al. , 2009a ) .

Of note, the lookout animate being developed indistinguishable lesions when compared to those of low dosage septic pigeons, proposing a mechanical transmittal of sporocysts from newly infected to the clean pigeon. Gastrointestinal transition or sloughing of sporocyst was non detected in all pigeons inoculated. Transmission via contaminated imbibing H2O similar to transmittal of Trichomonas gallinae in pigeon flocks ( Kocan, 1969 ) hence seems to be probably. However, GI transition… . ( Schafe…

Unlike pigeons, poulets were insusceptible to unwritten infection with sporocysts. However, it can non be excluded that the parasite is infective for avian species other than poulet. This premise is supported by a close sequence homology with a Sarcocystis species of the White-fronted goose ( Anser albifrons ) in Lithuania as described antecedently ( Butkauskas et al. , 2007 ; Olias et al. , 2009b ) . In general, bird-infecting Sarcocystis species are suggested to hold a low host-specifity and therefore might exhibit a high potency to do disease in incidental and deviant host species ( Box & A ; Smith, 1982 ; Mansfield et al. , 2008 ; Elsheikha, 2009 ) . In peculiar, S. falcatula is known to do an acute fatal pneumonic disease in non-American psittacines ( Clubb & A ; Frenkel, 1992 ) . Although domestic pigeons were susceptible to experimental infection with S. falcatula, poulets failed to exhibit any clinical disease or histopathological lesions ( Box & A ; Smith, 1982 ) . It is hence alluring to theorize that a similar host scope might besides be for the S. calchasi. Previously, several other instances of acute deceases in birds have been reported due to schizogony in the lungs of as yet unidentified Sarcocystis species ( Suedmeyer et al. , 2001 ; Villar et al. , 2008 ; Ecco et al. , 2008 ) . Furthermore, several instances of fatal cardinal nervous sarcocystosis have been reported in birds, nevertheless, familial word pictures of the causative Sarcocystis species were missing ( Gustafsson et al. , 1997 ; Dubey et al. , 2001 ; Siegal-Willott et al. , 2005 ) . The scope of Northern goshawks extends over most of the northern hemisphere and several other birds of quarries have late been reported to harbor a great assortment of genetically and morphologically different Sarcocystis species ( Ferguson-Lees, 2001 ; Yabsley et al. , 2009 ) . Therefore, despite S. calchasi, it seems sensible to presume that several other as yet unidentified species might show an unrecognized menace for several avian species.

In drumhead, we have shown that S. calchasi which rhythms between Northern goshawks and domestic pigeons is extremely infective for domestic pigeons. Remarkabely, a biphasic disease developed in domestic pigeons after experimental infection with polyuria and apathy as a first stage and cardinal nervous marks as a 2nd stage of the clinical class.


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