[The significance of cryptosporidiosis for the health of calves in Switzerland]. / Die Bedeutung der Cryptosporidiose für die Kälbergesundheit in der Schweiz.

INTRODUCTION: Diarrhea in calves is one of the most important cattle diseases in Switzerland. The diagnosis and treatment of calf diarrhea represent a major challenge. Single-celled Cryptosporidium parasites are the most prevalent causative agents of calf diarrhea besides rotavirus in the first weeks of life, and are responsible for about 50% of diarrheal cases. Cryptosporidium parvum has been described as a cause of diarrhea in one to three weeks old calves since the 1970s. Oral ingestion of persistent environmental oocysts results in severe diarrhea lasting four to six days and shedding of large numbers of infectious oocysts. A tiny amount of 10 oocysts is already sufficient to cause disease. Detailed knowledge about the epidemiology and virulence of the different C. parvum strains is still lacking. In addition, current diagnostic tests cannot reliably distinguish between non-pathogenic (e.g. C. bovis) and pathogenic Cryptosporidium species. Until now, no effective therapeutic drug or vaccine against calf cryptosporidiosis has been found. Water-borne epidemics and the zoonotic potential of Cryptosporidium in immunodeficient patients are of great medical importance. The increasing number of cryptosporidiosis cases associated with high infant mortality in less industrialized and impoverished regions (including South-East Asia and sub-Saharan Africa) has intensified the research in recent years. The recent discoveries of new therapeutics against C. parvum may benefit calf medicine in the near future. This review article reports on these new developments, highlights calf cryptosporidiosis in Switzerland and draws attention to a new research project.

INTRODUCTION: La diarrhée chez les veaux est l'une des maladies du bétail les plus courantes en Suisse. Le diagnostic de la cause et le traitement de la diarrhée des veaux représentent un défi majeur. En Suisse, les cryptosporidies sont, avec les rotavirus, l'agent causal le plus fréquent de diarrhée du veau dans les premières semaines et elles sont responsables d'environ 50% des cas. Le parasite unicellulaire Cryptosporidium parvum a été décrit depuis les années 1970 comme un agent de diarrhée chez les veaux d'une à trois semaines. Après ingestion orale d'oocystes persistants dans l'environnement, il se produit après quelques jours une diarrhée sévère de quatre à six jours avec excrétion massive d'oocystes déjà infectieux. Même quelques oocystes persistants dans l'environnement peuvent être pathogènes. Du point de vue épidémiologique, il existe encore de grandes lacunes dans la connaissance de la variabilité suspectée dans la virulence de diverses souches de C. parvum. En outre, des espèces non pathogènes (entre autres Cryptosporidium bovis) peuvent être présentes chez les veaux, qui ne se distinguent pas de C. parvum avec les tests diagnostiques actuels. Jusqu'à présent, aucun médicament efficace sur le plan thérapeutique et aucun vaccin contre la cryptosporidiose du veau n'ont été trouvés. En médecine humaine, les épidémies transmises par l'eau (en particulier aux États-Unis) et l'importance zoonotique des cryptosporidies comme pathogènes opportunistes chez les personnes immunodéficientes jouent un rôle de premier plan. La forte morbidité de la cryptosporidiose associée à une forte mortalité infantile dans les régions les moins industrialisées et les plus pauvres (entre autres en Asie du Sud-Est et en Afrique subsaharienne) ont relancé la recherche sur ces parasites au cours des dernières années. En particulier, la découverte de nouveaux médicaments contre C. parvum est susceptible de bénéficier à la médecine du veau dans un proche avenir. Cet article de synthèse fait le point sur ces nouveaux développements mais surtout sur la cryptosporidiose du veau en Suisse et attire l'attention sur un nouveau projet de recherche.

Toltrazuril does not show an effect against pigeon protozoal encephalitis.

The protozoan parasite Sarcocystis calchasi causes a severe neurologic disease in domestic pigeons (Columba livia f. dom.) named pigeon protozoal encephalitis. Recently, the parasite has also been reported in psittacines causing a virtually identical disease with fatal outcome. So far, an etiological treatment of S. calchasi infections in pigeons or psittacines is unknown. The present study evaluates the effectiveness of the anticoccidian drug toltrazuril against S. calchasi and the influence of the timepoint of treatment. Therefore, nine domestic pigeons were inoculated with 400 S. calchasi sporocysts and treated with toltrazuril (25 mg/kg) in groups of three pigeons each at dpi 10/11 and dpi 40/41 and on two consecutive days at the onset of neurologic signs. After euthanasia at dpi 73, tissue samples including brain and skeletal muscles were examined by histology and S. calchasi-specific real-time PCR. All pigeons independent of the group developed neurologic signs from dpi 49 onwards. Histology identified sarcocysts in the skeletal muscles and a granulomatous encephalitis in the brains. The relative amount of S. calchasi DNA was on a comparable level in all pigeons. Consequently, toltrazuril was demonstrated to be not effective against S. calchasi with the applied treatment regime. Longer treatment periods or agents other the toltrazuril may be considered for further investigations. So far, preventive measures like roofing of aviaries for prevention of infection and regular disinfection remain the most important factor in the control of S. calchasi infections.

Metastatic endocervical adenocarcinoma in a western lowland gorilla (Gorilla g. gorilla): no evidence of virus-induced carcinogenesis.

BACKGROUND: Cervical Cancer is the second most common cancer among women. Nevertheless, similar tumours have only been rarely described in Great Apes. This report characterizes the pathological and molecular features of a metastatic endocervical adenocarcinoma in a Western lowland gorilla (Gorilla g. gorilla). METHODS: Necropsy and histopathology was performed to identify the cause of the disease in an cachectic 50-year-old western lowland gorilla. Immunohistochemistry for Ki67, oestrogen receptor alpha and ERBB2 was performed to characterize the tumor. In addition, Pan-herpesvirus and Pan-papillomavirus PCR were used to identify a possible viral cause. RESULTS: The endoccervical carcinoma showed a severe metastatic spread to the lung, brain and bone and was herpesvirus and papillomavirus-negative. Most tumor cells were ERBB2-positive, 15% of tumor cells were Ki67-positive and only few tumor cells had oestrogen receptor alpha expression. CONCLUSIONS: Histopathologically and immunohistochemically, the tumour had striking similarities to human endocervicial adenocarcinomas of the common type. However, PCR analysis failed to identify herpes- or papillomaviral DNA in the tumor at the time of necropsy, thus leaving the question for cause of the disease open.

Unusual biphasic disease in domestic pigeons (Columba livia f. domestica) following experimental infection with Sarcocystis calchasi.

A novel Sarcocystis species has recently been reported in the domestic pigeon (Columba livia f. domestica) as intermediate host, causing severe central nervous signs similar to Paramyxovirus-1 or Salmonella Typhimurium var. cop. infection. Transmission of the parasite via the northern goshawk (Accipiter gentilis) as definitive host has been established. Experimental infection of domestic pigeons with sporocysts excreted by experimentally infected northern goshawks reproduced the natural infection in the pigeon, proving the causative role of the parasite in the disease. Here, we describe in greater detail the course of the fulminant biphasic disease depending on the infectious dose. Pigeons infected with 10(3) or 10(4) sporocysts showed clinical signs of polyuria and apathy around 10-11 days postinfection (dpi) and sudden neurological signs 51-57 dpi as a second phase of disease. Pigeons infected with higher doses died within 7-12 dpi, also showing polyuria and apathy but without nervous signs. At necropsy, livers and spleens had multifocal necroses and infestations with parasitic stages, namely, schizonts. Moreover, lesions and schizonts were also found in the lung, bone marrow, and next to blood vessels in the connective tissue of various organs. Pigeons infected with 102 sporocysts remained symptomless until 58-65 dpi, when sudden central nervous signs occurred. Major histopathologic findings of pigeons with neurological signs were encephalitis and myositis of virtually every skeletal muscle with high infestations of sarcocysts. Only mild myocarditis and very few cysts were found in the heart muscles. Importantly, a sentinel pigeon developed identical lesions when compared to those of low-dose infected pigeons, suggesting a risk of mechanical transmission of sporocysts from freshly infected to uninfected pigeons in a flock. By contrast, chickens failed to develop any clinical signs or pathologic lesions in the same experiment. The findings further characterize the new highly pathogenic disease in domestic pigeons, which clinically mimics paramyxovirosis and salmonellosis in both phases of the disease and exclude chickens as further intermediate host species.

A novel Sarcocystis-associated encephalitis and myositis in racing pigeons.

Sarcosporidian cysts in the skeletal muscle of domestic pigeons (Columba livia f. domestica) have previously been attributed to infection with Sarcocystis falcatula, which is shed in the faeces of the opossum (Didelphis virginiana). Here, we describe fatal spontaneous encephalitis and myositis associated with Sarcocystis infections in three flocks of racing pigeons with 47 of 244 animals affected. The clinical course was characterized by depression, mild diarrhoea, torticollis, opisthotonus, paralysis and trembling. Histopathological examination of 13 pigeons revealed generalized severe granulomatous and necrotizing meningoencephalitis and myositis with sarcosporidian cysts. Light and transmission electron microscopy identified cysts in heart and skeletal muscle of 1 to 2 mm in length and 20 to 50 microm in width. These were subdivided into small chambers by fine septae and filled with lancet-shaped cystozoites (7.5 x 1.5 microm) and dividing metrocytes, which is characteristic for Sarcocystis. The cysts had smooth walls and were devoid of protrusions typical of S. falcatula. Polymerase chain reaction amplification and sequencing of the internal transcribed spacer region (ITS-1) and the complete 28S rRNA identified a novel Sarcocystis species with only 51% ITS-1 nucleotide sequence similarity with S. falcatula. A phylogenetic comparison of the 28S rRNA revealed close sequence homologies with Frenkelia microti, Frenkelia glareoli and Sarcocystis neurona. The clinical, histopathological, electron microscopic and genetic data are unlike any previously described protozoan infections in pigeons, suggesting a novel, severe disease due to an as yet undescribed Sarcocystis species.

Thyroid transcription factor-1 is a specific marker of benign but not malignant feline lung tumours.

Feline lung tumours are currently subclassified according to the criteria of the World Health Organisation, but this scheme contains overlap in the tumour phenotype. The aims of the present study were to re-evaluate the histological features of feline lung tumours and to correlate these with expression of the markers thyroid transcription factor (TTF)-1 and Ki67. TTF-1 was found to be a highly specific marker for neoplastic and non-neoplastic lung tissue and thyroid tissue, but was expressed only weakly in invasive lung tumours. A combined semiquantitative score for Ki67 and TTF-1 expression correlated well with differentiation and invasive behaviour of the tumours and may thus be of potential value for evaluation of feline lung tumours.

The pathology of comparative animal models of human haemochromatosis.

Haemochromatosis is one of the most common human hereditary diseases. It is defined as a pathological condition with normal iron-driven erythropoiesis, but toxic accumulation of iron in vital organs, which is caused by mutations in any gene that encodes a protein involved in limiting the entry of iron into the blood. Iron storage diseases have also been described in several mammalian and avian species and these have been proposed as comparative animal models for human haemochromatosis. Genetically engineered mouse strains with mutations in iron metabolism genes model several aspects of human haemochromatosis and study of these animals has facilitated understanding of the disease. Spontaneously arising iron storage diseases in non-murine species also overlap in some clinicopathological aspects with human haemochromatosis. However, the lack of conclusive information on the molecular biology of theses species-specific diseases and the common impact of dietary iron concentration on disease progression in most species limit their usefulness as comparative models.

Intraosseous lipoma in the ulna and radius of a two-year-old Leonberger.

This report describes a case of intraosseous lipoma in a two-year-old Leonberger. The dog was presented with a history of ten month lameness in the right forelimb. A massive swelling from the elbow to the carpus of the right forelimb was visible. Treatment with anti-inflammatory medications by the local veterinarian for ten months was unsuccessful and the dog was presented at the university clinic. Radiographic images showed that the diaphyseal part of the ulna was affected by extensive cyst-like osteolysis. Furthermore, the distal metaphysis of the radius showed cyst-like osteolytic changes. The soft-tissue mass and parts of the ulna periosteum were surgically resected. Histopathological analysis of the mass in combination with clinical, surgical and radiographic findings was diagnostic for an intraosseous lipoma. The dog had a good long-term outcome as it was free of any signs of recurrence at the follow-up examinations performed after 18 months and after five years. To the authors' knowledge, this is the first description of intraosseous lipoma in a dog.

Iron overload syndrome in the black rhinoceros (Diceros bicornis): microscopical lesions and comparison with other rhinoceros species.

The African black rhinoceros (Diceros bicornis) has adapted to a low iron diet during evolution and is thus prone to iron overload in captivity, which is associated with a number of serious disorders. A S88T polymorphism in the HFE gene has been suggested as a potential genetic basis of increased iron uptake in the black rhinoceros, while the Indian rhinoceros is thought to be unaffected by iron overload in captivity. In the present study, the histopathology and distribution of iron accumulations in five black rhinoceroses with iron overload syndrome were characterized and compared with three Indian rhinoceroses (Rhinoceros unicornis) and one African white rhinoceros (Ceratotherium simum). At necropsy examination, iron storage in black rhinoceroses was not associated with gross lesions. Microscopically, the most consistent and highest degree of iron load was found in the spleen, liver, small intestine and lung. There was minimal fibrosis and single cell necrosis in the liver. Endocrine organs, lymph nodes, heart and kidney were less often and less markedly affected. Unexpectedly, Indian rhinoceroses also showed iron load in the spleen and smaller amounts in organs similar to the black rhinoceros except for in the heart, while the white rhinoceros had only minor detectable iron storage in intestine, liver and lung. Sequence analysis confirmed the HFE S88T polymorphism in black but not in Indian rhinoceroses. The results indicate that Indian rhinoceroses may also be affected by iron storage in captivity, although in a milder form than the black rhinoceros, and therefore challenge the relevance of the S88T polymorphism in the HFE gene of black rhinoceroses as the underlying cause for iron overload.

Iron storage disease in red deer (Cervus elaphus elaphus) is not associated with mutations in the HFE gene.

Iron storage diseases are rare conditions of dysregulated iron metabolism in man and animals. A genetic basis has been confirmed only for human haemochromatosis. Iron storage disease was diagnosed in six related, 2-year-old male red deer of the same herd. These animals presented with weight loss and rough hair coats. Haematological examination was unremarkable. At necropsy examination, gross lesions were restricted to cachexia. Microscopical examination revealed severe, diffuse hepatocellular necrosis and iron accumulation in hepatocytes, Kupffer cells, cardiac myocytes and renal tubular cells in all affected animals. Four animals also had moderate bridging fibrosis in the liver. Hepatic iron concentrations were increased (1108-2275 mg/kg wet weight; reference range 100-200 mg/kg). Drinking water in rusty iron tubs in the deer park contained eight times more iron than the accepted level for human drinking water. To test for a possible genetic basis of increased iron uptake and storage in red deer, the cervid haemochromatosis gene (HFE) was identified. Sequence comparisons between the six diseased animals and three healthy free-ranging unrelated animals failed to identify differences in the HFE sequences. Furthermore, the disease was not associated with common amino acid substitutions reported in human patients with haemochromatosis, including C282Y and H63D. Polymorphisms in other non-HFE genes involved in iron metabolism may have led to a higher sensitivity to iron and this, together with the high iron content of the drinking water, may have been the cause of the observed iron storage in these red deer.

Sarcocystis calchasi-associated neurologic disease in a domestic pigeon in North America.

Tissue cysts of a protozoan parasite were present in the skeletal muscle of a domestic pigeon (Columba livia f. domestica) with neurologic disease in Minnesota, USA. The animal had a severe granulomatous meningoencephalitis. The cysts were slender, up to 1 mm long and up to 0.03 mm in diameter. The cysts had a smooth wall without projections. Size and wall morphology were compatible with Sarcocystis calchasi. Polymerase chain reaction using S. calchasi-specific primers resulted in a specific amplicon from the skeletal muscle but not from the brain. Sequencing of the highly variable genomic regions ITS1 and D2 revealed 100% nucleic acid identity with the German strain of S. calchasi. Sarcocystis calchasi is the cause of an emerging lethal disease in pigeons in Germany. This is the first description of the parasite outside of Germany.

Cerebral phaeohyphomycosis in a green iguana (Iguana iguana).

Cerebral phaeohyphomycosis was diagnosed in a 4-year-old green iguana (Iguana iguana) with paroxysmal spastic paralysis of all limbs and circling motion. Formalin-fixed tissues were collected at necropsy examination and submitted for evaluation. The left cerebrum and the left ventricle were replaced by a solid brown coloured mass. Microscopical examination revealed the presence of necrotizing and granulomatous encephalitis affecting the cerebrum, cerebellum and brainstem, with severe vasculitis and intralesional dematiaceous fungal hyphae. No other lesions or fungi were found in other organs. Fungi were identified as Oidiodendron spp. by sequence analysis of the internal transcribed spacer (ITS) region 1 extracted from formalin-fixed and paraffin wax-embedded brain tissue. This case represents the first report of phaeohyphomycosis with tropism for the central nervous system in a reptile. In the absence of fresh tissue, the diagnosis in such cases may be assisted by molecular analysis of fixed tissue specimens.