Clinical, pathological and epidemiological findings in three outbreaks of ovine protozoan myeloencephalitis

Morphometric Study of Microscopic Cysts of Sarcocystis Sp. in Sheep Carcasses

Muscular samples of the oesophagus and diaphragm of 335 sheep collected from the slaughterhouse of El Harrach were analyzed by the histopathological method to describe the morphology of two species of Sarcocystis: S. arieticanis and S. tenella. The cysts were counted and measured with a micrometer for their dimensions. A total of 895 cysts were measured. The width, length, shape index (length/width), the thickness of the wall and the length of the projections were recorded. The thick-walled cysts of S. tenella were 10—450 μm long (the mean ± SD value was 50.35 μm ± 1.380) and 1—110 μm (the mean ± SD value was 27.51 μm ± 0.533) wide. The cyst walls were 0.5—4 μm thick (the mean ± SD value was 1.547 μm ± 0.020) and provided with radial striations. The shape index was 1—14 μm (the mean ± SD value was 1.93 ± 0.045). While in the S. arieticanis, the cyst wall was thin and had long hair-like protrusions, the cysts measured 8—780 μm (the mean ± SD value was 123.13 μm ± 12.799) in length and 5—100 μm (the mean ± SD value was 37.00 μm ± 1.68) in width. The hair-like protrusions reached a length of 3—14 μm (the mean ± SD value was 5.428 ± 0.353) and the shape index was 1—17 μm (the mean ± SD value was 3.10 ± 0.281). For the length, the width and the shape index, the differences were statistically significant between thin-walled cysts and thick-walled cysts. The general structural features of the cysts, previously described by other authors, were confirmed.

First molecular characterization of Sarcocystis tenella in Tatra chamois (Rupicapra rupicapra tatrica) in Poland

In this study, sarcocysts from three Polish Tatra chamois were isolated and identified using morphological and molecular methods for the first time. Six cysts were found in the latissimus dorsi muscle and another two in the diaphragm. No sarcocysts were detected in the myocardium, tongue, and esophagus. The isolated cysts were long with rounded ends, 0.35-0.61 mm in length, and 0.02-0.06 mm in width. All the sarcocysts were identified as Sarcocystis tenella on the basis of light microscopy and sequencing of cytochrome C oxidase subunit I (cox1) and small-subunit rRNA (ssu rRNA) genes. Comparative analysis showed a 99.23% identity of the cox1 gene sequences from Tatra chamois and sheep sarcocysts, and an even higher degree of sequence identity (99.88%) was documented in the case of the ssu rRNA gene. When compared at a haplotype level, all the sheep sequences of cox1 differed from those isolated from Tatra chamois. In contrast, one out of the two ssu rRNA haplotypes from the sheep isolates was identical with the haplotype from Tatra chamois. In conclusion, we showed that cox1 and ssu rRNA genes can be used as genetic markers for identification of the S. tenella, with cox1 gene providing better resolution during phylogenetic analyses. However, both genetic population analysis and phylogenetic inference with cox1 and ssu rRNA genes demonstrated that they do not constitute good markers for spatial differentiation of S. tenella.

Sarcocystosis in a stillborn lamb

Confirmed congenital sarcocystosis has been reported extremely rarely in domestic ruminants. Sarcocystosis was diagnosed in a stillborn lamb with microscopic lesions predominantly in the central nervous system and placenta. Encephalitis was characterized by multiple foci of glial nodules some with central necrosis, perivascular cuffing and vascular occlusion, while placental lesions consisted of multifocal necroses, inflammation and mild calcification. Immature and mature schizonts were found in vascular endothelium of several organs. It is suggested that the protozoa were Sarcocystis tenella based on their morphology, location and as this is the most pathogenic Sarcocystis sp. parasitizing sheep.

Identification of Sarcocystis capracanis in cerebrospinal fluid from sheep with neurological disease

Protozoal merozoites were identified in the cerebrospinal fluid of two sheep with neurological disease in the UK. Polymerase chain reaction (PCR) identified the merozoites as Sarcocystis capracanis, a common protozoal pathogen of goats. This is the first report of this species infecting sheep and may represent an aberrant infection with sheep acting as dead end hosts, or alternatively could indicate that sheep are able to act as intermediate hosts for S. capracanis, widening the previously reported host range of this pathogen. It is possible that S. capracanis is a previously unrecognised cause of ovine protozoal meningoencephalitis (OPM) in the UK.

Calf mortalities associated with Sarcini ventriculi infection

Abomasal rupture associated with Sarcini ventriculi as likely cause of neonatal mortalities on a dairy farm Immune-mediated anaemia and thrombocytopenia suspected in a seven-month-old Holstein-Friesian heifer Buttercup (Ranunculus species) poisoning causing blindness and ear twitching in five-month-old lambs Diagnosis and reporting of sheep scab Diarrhoea in 200-day-old gilts due to coccidosis These are among matters discussed in the disease surveillance report for September and October from SAC Consulting: Veterinary Services (SAC C VS).

Aborto ovino associado com infecção por Sarcocystis sp

Infecções por protozoários têm distribuição mundial e podem causar aborto, nascimentos prematuros e ou morte fetal em diversas espécies animais. Em julho de 2004, oito ovinos Corriedale apresentaram problemas reprodutivos caracterizados por aborto e natimortalidade no terço final da gestação. Dessas oito perdas, um natimorto macho foi enviado ao Setor de Patologia Veterinária para necropsia. Alterações macroscópicas não foram observadas durante a necropsia. Lesões histológicas foram observadas principalmente no cérebro e coração e se caracterizaram por encefalite não-supurativa multifocal acentuada associada à presença de protozoários no interior de células endoteliais e vasos sanguíneos e miocardite não-supurativa focal leve. Alguns desses organismos apresentaram formato de roseta. O teste de imunoistoquímica anti-Toxoplasma gondii foi negativo, mas houve reação cruzada com anticorpo anti-Neospora caninum. O exame de imunofluorescência direta para Leptospira sp. foi negativo. A bacteriologia aeróbica e micro-aeróbica não revelou crescimento significativo. Esses achados foram compatíveis com o diagnóstico de Sarcocystis sp.

Clinicopathological findings in sheep from Sardinia showing neurological signs of disease

Histopathological and bacteriological examinations were performed on 178 brains from Sardinian sheep which were showing neurological signs. The sheep represented the total number of sheep with neurological syndromes submitted for diagnostic investigations over a three-year period in Sardinia. Scrapie was detected in 57 cases, cerebrocortical necrosis in 25, intoxication by a typical Mediterranean plant (Cistus species) was suspected in 25, coenurosis was detected in 11 cases, Listeria monocytogenes in eight cases and focal symmetrical encephalomalacia in six cases. Non-suppurative inflammatory changes were observed in three of the brains and suppurative changes were noted in two. Lesions restricted to the spinal cord were found in three cases. In the remaining 38 cases there were no significant neuropathological changes.