Ultrasonography screening of hepatic cystic echinococcosis in sheep flocks used for evaluating control progress in a remote mountain area of Hejing County, Xinjiang.

BACKGROUND: Although ultrasonography (US) has been widely used in the diagnosis of human diseases to monitor the progress of cystic echinococcosis (CE) control, the screening method for hepatic CE in sheep flocks requires adjustment. In this study, we used a US scanner to screen sheep flocks and evaluated the efficacy of dosing dogs once a year with praziquantel for 7 years from 2014 to 2021. METHODS: All sheep in the three flocks were screened using an ultrasound scanner in 2014 and compared with the prevalence of infection in 2021 in Bayinbuluke, Xinjiang, China. Sheep age was determined using incisor teeth. Cyst activity and calcification were determined using US images. The dogs were dewormed with praziquantel once a year to control echinococcosis in the community. RESULTS: Three flocks had 968 sheep in 2014, with 13.22%, 22.62%, 18.7%, 27.27%, 11.88%, and 6.3% of sheep aged 1, 2, 3, 4, 5, and ≥ 6 years old, respectively. US scanning revealed that the overall CE prevalence was 38.43% (372/968), with active cysts and calcified cysts present in 9.40% (91/968) and 29.02% (281/968) of the sheep, respectively. For the young sheep aged 1 and 2 years, the prevalence of active and calcified cysts was: 1.56% and 0.91%, and 10.94% and 18.72%, respectively. Approximately 15.15% and 16.52% of the 4- and 5-year-old sheep, respectively, harbored active cysts. There was no significant difference in the infection rates of sheep between 2014 and 2021 (P > 0.05). CONCLUSIONS: US is a practical tool for the field screening of CE in sheep flocks. One-third of the sheep population in the flocks was 1-2 years old, and these sheep played a very limited role in CE transmission, as most of the cysts were calcified. Old sheep, especially culled aged sheep, play a key role in the transmission of CE. Dosing dogs once a year did not affect echinococcosis control.

To scan or not to scan? The economics of transthoracic ultrasonography for 'whole-flock' ovine pulmonary adenocarcinoma screening in UK sheep flocks.

BACKGROUND: Transthoracic ultrasonography (TTUS) is currently the only widely used method to diagnose suspected preclinical or subclinical cases of ovine pulmonary adenocarcinoma/Jaagsiekte (OPA) in live sheep. However, the economic impact of using TTUS as a screening test has not been described previously. METHODS: Test characteristics for TTUS in a low-prevalence situation were obtained from a previous study of 1074 breeding ewes that underwent TTUS with an experienced operator. The economic impact was modelled using a 10,000-iteration partial budget simulation and probability sensitivity analysis to explore the relative influence of model variables. RESULTS: In flocks of this size, culling true-positive and false-positive cases resulted in an estimated median net loss of £4647 (interquartile range: £3537-£6006), determined primarily by replacement ewe value and the cost of TTUS per ewe. CONCLUSION: The results of this study emphasise that great caution should be exercised by practitioners when determining if TTUS is appropriate as a screening test for OPA in low-prevalence flocks or subpopulations within a flock, such as younger age groups, where the losses incurred through the inadvertent culling of healthy sheep may significantly exceed any benefit derived from culling preclinical/subclinical cases.

Efficacy of high-throughput transthoracic ultrasonographic screening for on-farm detection of ovine pulmonary adenocarcinoma.

BACKGROUND: The aim of this study was to evaluate the efficacy of high-throughput on-farm transthoracic ultrasound (TUS) to screen for ovine pulmonary adenocarcinoma (OPA), an infectious ovine disease of increasing concern. No other routine diagnosis of preclinical OPA is available, or any vaccine or treatment. METHODS: More than 80,000 rapid TUS scans were applied on farms with a history of OPA. The TUS results from a convenience sample of 171 TUS-negative and 269 TUS-positive sheep were compared with postmortem histology/immunohistochemistry results, the 'gold standard' reference test for OPA diagnosis. These results, together with new data on within-flock prevalence, allowed estimation of the efficacy of rapid TUS screening to identify OPA (defined as tumours of larger than 1 cm) on-farm. RESULTS: The TUS screening had an estimated specificity of 0.998 (95% confidence interval [CI]: 0.998-0.999) and an estimated sensitivity of between 0.76 (95% CI: 0.72-0.79) and 0.99 (95% CI: 0.97-0.99) depending on the presumed false-negative rate applied to the calculation. CONCLUSION: High-throughput TUS should be considered for screening to identify individual sheep with OPA and has potential application to indicate flocks at low risk of OPA. However, lower efficacy is likely if conducted by less experienced persons.

Computed tomographic diagnosis of necroulcerative reticulorumenitis with portal venous gas in a lamb.

A 2-month-old, intact male Merino sheep was presented for acute inappetence and pyrexia. Contrast-enhanced abdominal computed tomography identified reticulorumenal intramural gas with suspected ruminal ulceration, arborizing portal venous gas, and mild peritoneal fluid. The lamb was treated medically for presumptive ulcerative reticulorumenitis and non-septic peritonitis. Over 10 days, the lamb initially showed mild improvement before clinical deterioration and was ultimately euthanized. Definitive diagnosis of necrotizing, ulcerative reticulorumenitis was made via necropsy with histopathology. An underlying cause was not determined. Key clinical message: Contrast-enhanced computed tomography was effective in identifying gastric emphysema and portal venous gas associated with reticuloruminal ulceration.

Diagnostic par tomodensitométrie d'une réticulo-ruménite nécro-ulcérative avec gaz veineux porte chez un agneau. Un mouton mérinos mâle intact, âgé de 2 mois, a été présenté pour une inappétence aiguë et une pyrexie. La tomodensitométrie abdominale de contraste augmentée a identifié du gaz intramural réticuloruménal avec une ulcération ruminale suspectée, du gaz veineux porte arborescent et un léger liquide péritonéal. L'agneau a été traité médicalement pour une réticulo-ruménite ulcéreuse présumée et une péritonite non-septique. Sur une période de 10 jours, l'agneau a d'abord montré une légère amélioration avant une détérioration clinique et a finalement été euthanasié. Le diagnostic définitif de réticulo-ruménite ulcéreuse nécrosante a été posé suite à la nécropsie et l'histopathologie. Une cause sous-jacente n'a pas été déterminée.Message clinique clé:La tomodensitométrie assistée par contraste s'est avérée efficace pour identifier l'emphysème gastrique et le gaz veineux porte associés à l'ulcération réticulo-ruminale.(Traduit par Dr Serge Messier).

Detection of aluminium hydroxide-induced granulomas in sheep by computed tomography: A feasible approach for small ruminant lentiviruses diagnosis and research.

Aluminium (Al) hydroxide use as adjuvant induces local formation of long-lasting subcutaneous granulomas in sheep. Macrophages within these granulomas have been identified as a new small ruminant lentivirus (SRLV) replication site in naturally infected animals. Diagnosis of Al hydroxide-induced granulomas in sheep is mostly based on postmortem observations but little information is available on in vivo detection. Computed tomography (CT) is used for studying these reactions in other animal species. To determine if CT could be a tool for in vivo diagnosis and research of subcutaneous Al hydroxide-induced granulomas in sheep. A retrospective survey on thoracic CT scans was performed on 46 adult sheep. Analysis included absence or presence, number and location of subcutaneous nodules. Thoracic CT scans and pathological studies were prescribed to two further sheep. Single or multiple subcutaneous nodules were detected in 26 (56.52%) sheep. One or two nodules per animal were most often observed (36.95%). Size ranged between 1.5 and 4.5 cm. Pre-contrast two-dimensional (2D) CT images showed focal or multifocal increases in subcutaneous tissue thickness. Post-contrast 2D CT images revealed hypointense areas in the centre. Histopathology indicated the presence of granulomas composed by a large number of activated macrophages, surrounding a central core of necrosis. Large intracytoplasmic Al-positive aggregates were demonstrated by lumogallion staining. CT is a useful tool to detect subcutaneous Al hydroxide-induced granulomas in vivo in sheep. CT provides a diagnostic and research tool that can be very useful in future works in Al hydroxide-induced pathology, SRLV infection, or both.

Control of cystic echinococcosis in the Middle Atlas, Morocco: Field evaluation of the EG95 vaccine in sheep and cesticide treatment in dogs.

BACKGROUND: Cystic echinococcosis (CE) is an important cause of human morbidity and mortality worldwide, particularly in Morocco and other North African countries. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the potential of three strategies to reduce Echinococcus granulosus transmission: (1) 4-monthly treatment of dogs with praziquantel, (2) vaccination of sheep with the EG95 vaccine and (3) a combination of both measures. These measures were implemented during four consecutive years in different areas of the Middle Atlas Mountains in Morocco. The outcome of the interventions was assessed through hydatid cyst (viable and non-viable) counts in liver and lungs using necropsy or in vivo ultrasound examination of the liver. A total of 402 lambs were recruited for annual vaccination with the EG95 anti-E. granulosus vaccine and 395 similar lambs were selected as non-vaccinated controls. At approximately four years of age the relative risk (estimated as odds ratio) for vaccinated sheep to have viable hydatid cysts compared with non-vaccinated controls was 3% (9.37% of the vaccinated sheep were found infected while 72.82% of the controls were infected; p = 0.002). The number of viable cysts in vaccinated animals was reduced by approximately 97% (mean counts were 0.28 and 9.18 respectively; p<0.001). An average of 595 owned dogs received 4-monthly treatment during the 44 months trial, corresponding to 91% of the owned dog population. Approximately, 5% of them were examined for E. granulosus adult worms by arecoline purge or eggs in feces (confirmed by PCR). The proportion of infected dogs significantly decreased after treatment (12% versus 35%; p<0.001). Post-treatment incidence of re-infestation corresponded to a monthly risk of 4% (95% CI: 3-6%). Treatment of owned dogs on a 4-monthly basis did not reduce the level of transmission of E. granulosus to sheep, nor did it enhance the level of control generated by vaccination of sheep with EG95, possibly because of unowned dogs and wild canids were not treated. CONCLUSIONS/SIGNIFICANCE: These data suggest that vaccination of sheep with EG95 has the potential to reduce the level of CE in Morocco and in other parts of the world with similar transmission dynamics. Under the epidemiological circumstances existing in the trial area, 4-monthly treatment of owned dogs with praziquantel was insufficient to have a major impact of E. granulosus transmission to sheep.

Intracranial squamous cell carcinoma in an Ovis aries.

Squamous cell carcinoma (SCC) is a malignant mucoepithelial tumor that affects pets and farm animals. Common sites are dorsal areas and/or areas of poor skin pigmentation exposed to mutagenic ultraviolet (UV) radiation. Novel ovine papillomavirus (OaPV3) was recently described in SCC lesions in Sardinia breed ovines. In 2017, a 7­year­old half­breed aries was presented with symptoms compatible with a vestibular syndrome. The animal was euthanized 1 month after the onset of clinical signs due to a lack of response to treatment and poor prognosis. A complete postmortem examination was performed. Necropsy revealed only a loss of incisors, associated with alveolar necrotic osteomyelitis, and left unilateral purulent nasal discharge. No other thoracic or abdominal lesions were observed. Opening of the skull revealed a cauliflower­like space­occupying mass. Histological examination showed trabecules and islands of squamous, neoplastic epithelial cells with the formation of concentric keratin layers. This raised the suspicion of SCC, which was confirmed with cytokeratin­positive immunostaining. Simplex PCR on the frozen tissue mass was negative for OaPV1, OaPV2, and OaPV3. This case report suggests that SCC, although rare, should be included in the differential diagnosis of cases of vestibular disorder.

Clinical, ultrasonographic, bacteriological, cytological and histological findings during uterine involution in ewes with pregnancy toxaemia and subsequent reproductive efficiency.

Objectives were to evaluate characteristics of uterine involution in ewes with pregnancy toxaemia during gestation and to study effects on subsequent reproductive performance. Pregnancy toxaemia was induced in ewes (A) by feeding an energy-deficient diet as confirmed by detecting ß-hydroxybutyrate concentrations in blood indicative of this disorder. There was also a control group (C). Animals were evaluated until the 60th day post-partum using clinical and ultrasonographic examinations. Vaginal swab samples and uterine biopsy tissue samples were collected for bacteriological and cytological examination; biopsy samples were prepared for histological examination. Ewes were subsequently placed with rams and reproductive performance was ascertained. Post-partum, during the ultrasonographic examination of the uterus, ewes of Group A had caruncle and uterine lumen diameters, as well as a uterine thickness greater than ewes of Group C. Post-partum uterine blood flow volume was greater in ewes of the A than C group. Neutrophils predominated in vaginal samples, with the neutrophil proportion being less in ewes of Group A than C. There were no differences in the uterine involution process between groups. During the subsequent reproductive season, all the ewes of Group A lambed normally and produced viable lambs. It is concluded that there were no adverse effects on subsequent reproductive performance of ewes previously affected with pregnancy toxaemia, when appropriate health management was performed.

Superficial swellings in sheep (Ovis aries) and goats (Capra hircus): Clinical and ultrasonographic findings.

This study describes the clinical presentation of superficial swellings and evaluates the utility of ultrasonography in the diagnosis of such swellings in sheep and goats. Ninety-three sheep and 73 goats were included in this study on the basis of presence of superficial swellings on the head (n=56), neck (n=16), chest wall (n=3), abdominal wall (n=40), umbilicus (n=14), scrotum (n=16), testes (n=1), udder (n=7), limbs (n=2), gluteal region (n=5), tail (n=1), and penile urethra (n=5). Ultrasonographic evaluation of these superficial swellings allowed the diagnosis of abscesses (n=54; 32.52%), cysts (n=12; 7.23%), hernias (n=57; 34.33%), hematomas (n=14; 8.44%), tumors (n=24; 14.45%), and urethral diverticula (n=5; 3.03%). Each lesion type could be precisely discriminated (sensitivity, 88-100%; specificity, 80-100%; and P=0.001). Ultrasonography was found to have a specificity of 100% for the diagnosis of hernias, urethral diverticula, and tumors, and a lower specificity of 80% for hematomas and 93% for abscesses when used for evaluation of superficial swellings in sheep and goats. In conclusion, ultrasonography is a unique, non-invasive diagnostic imaging tool that allows the diagnosis, differential diagnosis, and subsequent surgical treatment of different types of superficial swellings in sheep and goats.

Relationships among neuroscore, magnetic resonance imaging features, and intracranial pressure in sheep affected by slow-growing brain lesions.

Diagnosing high intracranial pressure by clinical and diagnostic imaging is particularly challenging for chronic or slow-growing lesions. The aim of this prospective case-control study is to determine whether the neuroscore and brain magnetic resonance imaging (MRI) are related to the direct measurement of intracranial pressure in sheep affected by intracranial slow-growing lesions due to chronic cerebral coenurosis (Coenurus cerebralis). Seventeen affected and 10 control sheep were included. All animals underwent a neurological examination, MRI of the brain, and direct measurement of intracranial pressure. The severity of clinical signs and MRI findings were scored. Data were statistically analyzed. The invasive intracranial pressure value was higher in affected animals. A severely altered neuroscore is related to an increased intracranial pressure beyond the normal threshold (P < 0.05). The volume of the calvarium was larger in affected animals than in control animals (P = 0.0001) and was positively influenced by the presence and volume of the parasitic cyst (r = 0.7881, P < 0.01). Several degrees of deviation and deformation of both the ventricular system and brain parenchyma were detected by MRI. Subjective MRI findings were not associated with intracranial hypertension. In conclusion, this study shows that in sheep affected by slow-growing lesions, severe alterations in the neuroscore and the results of objective MRI are related to an increased intracranial pressure beyond the normal threshold.

CT Scanning in Identification of Sheep Cystic Echinococcosis.

OBJECTIVE: We aim to determine the efficiency of CT in identification of cystic echinococcosis in sheep. METHODS: Fifty-three sheep with liver cysts confirmed by ultrasonography were subject to CT scan to evaluate the number, size, and type of the cysts in liver and lung, confirmed using necropsy. The correlation of numbers between liver cysts and lung cysts was calculated using Pearson analysis. RESULTS: Necropsy indicated a 98% consensus on size, location, number, and activity compared with CT scan. The viable cysts were 53.1% and 50.6% in the liver and lung, respectively. Among the cysts in liver, 35.5%, 9.5%, 5.7%, 10.2%, and 39.1% were Types CE1, CE2, CE3, CE4, and CE5, respectively. The cysts in the lungs, 17.4%, 26.9%, 12.1%, 11.6%, and 32.1%, were Types CE1, CE2, CE3, CE4, and CE5, respectively. A significant correlation was noticed between the number of cysts in liver and those in lung (R = 0.770, P < 0.001). CONCLUSIONS: CT scan is a suitable tool in determining the size and type of cystic hydatid cysts in both liver and lung of sheep. A significant correlation was noticed between the numbers in liver and lung, indicating that lung infection was likely due to the expansion of liver cyst burden pressure.

Efficacy of radiotherapy for the treatment of cystic echinococcosis in naturally infected sheep.

BACKGROUND: Radiotherapy is commonly used to treat cancers. To date, there has been no study focusing on the effects of radiotherapy on hydatid disease in large animals. In this study, we aim to investigate the efficiency and safety of radiotherapy for treating hydatid disease caused by Echinococcus granulosus in naturally infected sheep. METHODS: Ultrasound was used to screen naturally infected sheep in an echinococcosis endemic area in Xinjiang, China. A computer tomography (CT) scan confirmed the presence of hydatid cysts. Twenty sheep naturally infected with E. granulosus in the liver and/or lungs were randomly assigned into four groups receiving no irradiation, or X-ray irradiation of low (30 Gy), medium (45 Gy), and high dose (60 Gy), respectively. After three months of radiotherapy, a CT scan was performed to measure the changes in the cysts. The hepatic parasite cysts and host tissues were collected for histology and gene expression analysis. RESULTS: In the animals subject to irradiation, no significant differences were observed in their appetite, daily activities, and weight before and after radiotherapy. Severe calcification was noticed in the cysts subject to a high dose of radiation compared with the groups subject to low and medium doses. Hematoxylin and eosin staining showed that irradiation contributed to the damage of the cyst structure and nucleus in the germinal layers. Quantitative PCR demonstrated that expression of TPX and HSP70 significantly decreased in a dose-dependent manner (P < 0.05). The expression of the EPC1 decreased in the medium- and high-dose groups compared with the low-dose group (P < 0.05). Meanwhile, the expression of radiation-related apoptosis genes caspase-3 and Gadd45 decreased with an increase in the irradiation dose. CONCLUSIONS: Radiotherapy is an option with satisfactory efficiency and safety for treating cystic echinococcosis in sheep with partial response or stable disease at month 3. In future, inhibition of cystic activity using radiotherapy may serve as a new regimen for treating hydatid disease.

Clinical, pathological and molecular evaluations and CT scan screening of coenurosis (Coenurus cerebralis) in sheep and calves / Avaliação clínica, patológica e molecular e tomografia computadorizada de cenurose (Coenurus cerebralis) em carneiros e bezerros

Abstract The aims of this study were to diagnose coenurosis by means of computerized tomography (CT) scan imaging and molecular characterization of the CO1 gene using the polymerase chain reaction (PCR). Sheep and calves were necropsied, and CT scans on the cephalic region were performed on the animals. Sections of brain tissue infected with parasites were then stained with hematoxylin and eosin for microscopic examination. Material collected from brain cysts was fixed in 70% ethanol. PCR amplification was carried out using the CO1 mitochondrial gene. A total of 60 calves and 80 sheep were examined clinically and, of these, 15 calves and 38 sheep showed signs of depression, with counterclockwise circling movements and altered head carriage. Four sheep and one calf were necropsied, and C. cerebralis cysts were detected in all of them. A hypodense cyst was monitored in the right cerebellar hemisphere on a CT scan on one sheep. A cyst was found in the left frontal lobe on a CT scan on one calf. Microscopically, C. cerebralis cysts were surrounded by a fibrous or epithelial wall that presented necrosis on cerebral sections of both the sheep and the cattle. The CO1-PCR assay yielded a 446 bp band, which was sequenced and phylogenetically analyzed: the results confirmed the presence of T. multiceps. This study reports the first use of CT imaging on naturally infected calves and sheep for diagnosing coenurosis.

Resumo Os objetivos deste estudo foram diagnosticar cenurose por tomografia computadorizada (CT) por imagem de digitalização e caracterização molecular do gene CO1, usando a Reação em Cadeia da Polimerase (PCR). Ovelhas e bezerros foram necropsiados, e uma tomografia computadorizada da região cefálica foi realizada nos animais. Em seguida, cortes microscópicos de cérebro infectado com parasitas foram corados com hematoxilina e eosina e posterior avaliação ao microscópio de luz. Em seguida, o material recolhido de cada cisto cerebral foi fixado em etanol a 70%. A amplificação pela PCR foi realizada utilizando-se o gene mitocondrial CO1. Um total de 60 bezerros e 80 ovelhas foram clinicamente examinados e, desses, 15 bezerros e 38 ovelhas apresentaram sinais de depressão, com movimentos circulares em sentido anti-horário, e desvio da cabeça. Quatro carneiros e uma vitela foram necropsiados, e cistos de C. cerebralis foram detectados nos animais. Um cisto hipodenso foi monitorado no hemisfério cerebelar direito por imagem do CT de um carneiro. O cisto foi encontrado no lobo frontal esquerdo por imagem do CT de um bezerro. Microscopicamente, cistos de C. cerebralis foram envolvidos por uma parede fibrosa ou epitelial, apresentando necrose em ambos os cortes cerebrais de ovinos e de bovinos. O ensaio CO1-PCR produziu uma banda de 446 pb, sequenciado e submetido à filogenia, confirmou ser T. multiceps. Este estudo relata a primeira utilização de imagens de CT em bezerros e ovelhas naturalmente infectados para o diagnóstico de coenurosis.

Clinical, pathological and molecular evaluations and CT scan screening of coenurosis (Coenurus cerebralis) in sheep and calves.

The aims of this study were to diagnose coenurosis by means of computerized tomography (CT) scan imaging and molecular characterization of the CO1 gene using the polymerase chain reaction (PCR). Sheep and calves were necropsied, and CT scans on the cephalic region were performed on the animals. Sections of brain tissue infected with parasites were then stained with hematoxylin and eosin for microscopic examination. Material collected from brain cysts was fixed in 70% ethanol. PCR amplification was carried out using the CO1 mitochondrial gene. A total of 60 calves and 80 sheep were examined clinically and, of these, 15 calves and 38 sheep showed signs of depression, with counterclockwise circling movements and altered head carriage. Four sheep and one calf were necropsied, and C. cerebralis cysts were detected in all of them. A hypodense cyst was monitored in the right cerebellar hemisphere on a CT scan on one sheep. A cyst was found in the left frontal lobe on a CT scan on one calf. Microscopically, C. cerebralis cysts were surrounded by a fibrous or epithelial wall that presented necrosis on cerebral sections of both the sheep and the cattle. The CO1-PCR assay yielded a 446 bp band, which was sequenced and phylogenetically analyzed: the results confirmed the presence of T. multiceps. This study reports the first use of CT imaging on naturally infected calves and sheep for diagnosing coenurosis.

Ultrasonographic findings in two sheep with enzootic calcinosis.

INTRODUCTION: This report describes 2 sheep with enzootic calcinosis characterized by abnormal cardiovascular and respiratory findings and ascites causing abdominal distension. Both sheep were anorexic and listless and had increased heart and respiratory rates. Auscultation of the heart revealed a gallop rhythm in sheep 1 and a loud systolic heart murmur in sheep 2. The activities of liver enzymes were severely increased in both sheep. Abdominal ultrasonography showed severe ascites and congestion of the liver and caudal vena cava. Echocardiography in sheep 2 showed hyperechoic and markedly thickened mitral and aortic valves with moderate-severe mitral insufficiency and generalized cardiomegaly. Both sheep were euthanized and examined postmortem. In addition to ascites and pleural effusion, the principal lesions were nodular thickening of the heart valves and calcification of the aorta and other arteries. Nutrition of the sheep did not include hay pellets, but the sheep were kept together with alpacas and lamas and had access to the hay pellets of these animals. In addition visitors were allowed to feed the sheep with hay pellets offered by the zoo in a dispenser. The two types of hay pellets had Vit D concentrations of 9'900 IU VitD3/kg and 7'000 IU Vit D2/kg, respectively. The definitive diagnosis was enzootic calcinosis.

Clinical evolution of cerebral coenurosis from invasive to chronic infection in sheep and a goat.

This survey describes the evolution in vivo of Coenurus cerebralis in small ruminants. At presentation, neurological signs and cerebrospinal fluid (CSF) features were suggestive of multifocal or diffuse inflammatory reaction. Magnetic resonance imaging (MRI) captured the transition between the invasive and quiescent phase of the infection, revealing the concurrent presence of meningitis and small cysts. During the quiescent phase, in all animals, neurological symptoms disappeared, and cerebrospinal fluid was unremarkable while cysts grew progressively. Subsequently, the onset of neurological symptoms coincided with MRI signs of diffuse or localized increase of intracranial pressure, as confirmed by direct intracranial pressure measuring. All the animals had an excellent post-surgical recovery. This is the first report describing the evolution of coenurosis in vivo. Sequential imaging allowed describing interesting such as the death of some coenuri and different parasite growth rate in the same host.

Experimental Transmission of Bighorn Sheep Sinus Tumors to Bighorn Sheep (Ovis canadensis canadensis) and Domestic Sheep.

Bighorn sheep sinus tumors are a recently described disease affecting the paranasal sinuses of Rocky Mountain bighorn sheep (Ovis canadensis canadensis). Several features of this disease suggest an infectious cause, although a specific etiologic agent has not been identified. To test the hypothesis that bighorn sheep sinus tumors are caused by an infectious agent, we inoculated 4 bighorn sheep lambs and 4 domestic sheep lambs intranasally with a cell-free filtrate derived from a naturally occurring bighorn sheep sinus tumor; we held 1 individual of each species as a control. Within 18 months after inoculation, all 4 inoculated domestic sheep (100%) and 1 of the 4 inoculated bighorn sheep (25%) developed tumors within the ethmoid sinuses or nasal conchae, with features similar to naturally occurring bighorn sheep sinus tumors. Neither of the uninoculated sheep developed tumors. Histologically, the experimentally transmitted tumors were composed of stellate to spindle cells embedded within a myxoid matrix, with marked bone production. Tumor cells stained positively with vimentin, S100, alpha smooth muscle actin, and osteocalcin, suggesting origin from a multipotent mesenchymal cell. A periosteal origin for these tumors is suspected. Immunohistochemical staining for the envelope protein of JSRV (with cross-reactivity to ENTV) was equivocal, and PCR assays specific for these agents were negative.