Glycohistochemical characterization of histologically normal nasal mucosa and enzootic nasal tumor of sheep

Objective-To determine glycohistochemical characteristics of enzootic nasal tumors (ENTs) of sheep, compare results for ENT with those of histologically normal nasal mucosa of sheep, and identify the histologic origin of ENT. Sample-ENT and nasal mucosa samples obtained from cadavers of 5 adult Lacaune sheep with ENT and 5 Lacaune sheep unaffected by ENT, respectively. Procedures-Samples of ENT and nasal mucosa were collected from cadavers of sheep and sectioned. Conventional and lectin histochemical analyses were used to identify glycoconjugates in tissue sections on the basis of their principal chemical groups and principal terminal or internal oligosaccharidic glucidic residues, respectively. Results-ENTs had papillary and tubular portions. Cells in the papillary portion of ENTs had secretion and surface glycoconjugates, which included sulfated glycosaminoglycans and neutral and sialilated glycoproteins. Cells in the tubular portion of ENTs had surface glycoconjugates, which included neutral and sialilated glycoproteins. Both portions of ENTs had C(4)-acetylated sialoderivatives that were not detected in sections of histologically normal nasal mucosa. Conclusions and Clinical Relevance-The papillary portion of ENTs in sheep may originate from respiratory glands and goblet cells. The tubular portion of ENTs in sheep may originate from olfactory glands. Presence of C(4)-acetylated sialoderivatives in cells of ENTs could confer resistance against pathogens to those cells.     

Persistent efficacy of a long acting injectable formulation of moxidectin against natural infestations of the sheep nasal bot (Oestrus ovis) in Spain

Cydectin(?) 2% LA Solution for Injection for Sheep (Pfizer Animal Health) is a long-acting (LA) formulation of moxidectin for the treatment and prevention of mixed infections of gastro-intestinal nematodes, respiratory nematodes and certain arthropod parasites in sheep. To evaluate the duration of persistent efficacy against nasal bots (Oestrus ovis), a natural exposure study was conducted in Spain during the summer of 2011. One hundred and twenty nasal bot-free, Rasa Aragonesa sheep were randomly allocated to eight groups of 15 animals each. On Day 0, four groups were treated at the recommended dose rate of 1 mg moxidectin/kg bodyweight. Four groups remained untreated as negative controls. All animals were held in nasal bot-proof housing except for exposure to natural challenge when one group of treated sheep and one of group of control animals were transferred to a local pasture at either 0-20, 20-40, 40-60, or 60-80 days after treatment. Following challenge, sheep were scored for clinical signs of bot infestation, necropsied and the heads sectioned for larval recovery. Nasal bot larvae were retrieved from 7 to 11 control sheep following each exposure period indicating that adult bots were active throughout the study. In the first challenge up to 20 days after treatment, when sheep were slaughtered immediately after exposure, the majority of larvae were first instar (L1) and only 3 of the 15 control sheep were infested with second instars (L2). There was 100% efficacy against L2 and 38.1% reduction in the number of live L1 in the treated sheep but mean counts were not significantly different between treatment and control groups (P ≥ 0.05). For the subsequent exposure periods 20-80 days after treatment (necropsies 7-9 days after challenge), 6-10 sheep were infested with L1 and 9-11 control sheep were infested with L2 and third instars (L3). There was negligible efficacy against L1, but treatment with moxidectin resulted in 100% control of L2 and L3. These results are consistent with the biology of nasal bots and control with a systemic agent, as the slower growing L1 have limited feeding and are therefore less susceptible to systemic parasiticides. The study demonstrated that the persistent efficacy of this long-acting injectable formulation of moxidectin protects against the development of active O. ovis infestations for at least 80 days after treatment.     

Maedi-Visna virus infection in sheep. History and present knowledge

Briefly the history of maedi-visna and the major clinical symptoms are described. Examples are presented to demonstrate that the genetic composition of a breed determines whether or not sheep become sick after an infection with maedi-visna virus (mvv) or develop solely specific antibodies. The major pathway of transmission is not colostrum and milk, but a cell containing increased nasal discharge in cases of respiratory distress. The role of the environment and prophylactic measures against parasites is stressed, because even sheep of highly susceptible breeds can survive an infection under optimal conditions. The virus and subsequently the disease simply die out. The cooperation between clinicians and laboratories is necessary.     

Naturally occurring nasal obstructions in 11 sheep

Eleven adult sheep of various breeds were examined due to inspiratory dyspnea. Fiberoptic examinations conducted in 8 of the sheep revealed masses to be obstructing the nasal passages. Identification of the masses through histopathologic examination showed 7 to be adenocarcinomas, 1 a papillary adenoma, and 4 were cases of glandular hyperplasia with lymphoplasmacytic infiltration (nasal polyps). One ewe had both an adenocarcinoma and a polyp. Surgical removal of the masses was attempted on 6 of the sheep. Four of the 6 surgically-treated sheep have survived between 2 mo. - 2 years without recurrence of the obstruction.     

Comparison of infection rates of Oestrus ovis between sheep and goats kept in mixed flocks

Oestrosis is a nasal myiasis of sheep and goats caused by larvae of the fly Oestrus ovis and can lead to severe clinical signs, which together with the disturbance caused by the adult fly may result into serious economic losses. Infection rates and larval burdens are always higher in sheep than in goats after either natural or artificial infestation. The aim of this study was to compare the host preference of the adult fly O. ovis between sheep and goats in mixed flocks, where they are kept together under the same husbandry conditions and hence, are very similarly exposed to the fly preference. Blood sera samples were collected from a total of 397 sheep and 335 goats, from 43 mixed flocks located at different regions of Greece. Antibodies specific to O. ovis IgG were measured by ELISA. A flock was considered positive when at least one individual was positive, i.e. showed a seropositivity of >or=20% in relation to positive control sera. A total of 193 (48.6%) sheep and 58 (17.9%) goats were found to be seropositive against O. ovis. Thirty-eight (88.4%) out of 43 flocks had at least one seropositive animal. The mean seroconversion against O. ovis in animals from the different flocks was 38.6% and 13.6% for sheep and goats, respectively, whereas the variance of infection within each flock was 0-100%. The mean seropositivity between sheep that were found to be positive or negative was 60.6% and 5.4%, respectively, whereas the corresponding values between goats were 35.2% and 5.2%, respectively. No significant difference in the seroconversion values was noted between flocks from the different areas (P=0.817), whereas a very significant difference was observed between animal species (P=0.001). However, there was no significant difference when seroconversion comparisons were made within samples of the same animals species, sheep or goats from different flocks of all the regions included in the study (P=0.695). The results of this study clearly demonstrate that O. ovis has a widespread distribution in Greece, and the seroprevalence is significantly higher in sheep than goats (P=0.001).     

Diagnosis and outcome of nasal polyposis in 23 dogs treated medically or by endoscopic debridement

This study describes the clinical, diagnostic, and pathological characteristics of canine nasal polyps and how they responded to medical, endoscopic, and surgical treatments. The database of a multi-center veterinary endoscopy group was searched from 2010 to 2018. All dogs with a histological diagnosis of nasal polyposis that were undergoing endoscopic investigation (N = 23), were included. Clinical signs at presentation were sneezing (91%), nasal discharge (83%), stertor (74%), and frontonasal deformation (17%). Skull radiography on 13 dogs had alterations in 77% of cases, including turbinate lysis (6/13), increased radiopacity of one (4/13) or both (6/13) nasal cavities, and lysis of the nasal vomer bone (3/13). Nasal polyposis had a characteristic endoscopic appearance. There were clinical and diagnostic similarities between this cohort of dogs and dogs with nasal neoplasia, although dogs with nasal polyps were often younger and polypoid tissue was external to the nose. Steroid therapy alone was not effective in treating polyposis in dogs; however, endoscopic debulking with a laser and forceps was more effective.     

Paranasal sinus masses of Rocky Mountain bighorn sheep (Ovis canadensis canadensis)

This article describes 10 cases of paranasal sinus masses in Rocky Mountain bighorn sheep (Ovis canadensis canadensis). Among 21 bighorns that were examined from 11 herds in Colorado, 10 individuals (48%) from 4 herds (36%) had masses arising from the paranasal sinuses. Affected animals included 9 of 17 females (53%) and 1 of 4 males (25%), ranging in age from approximately 2 years to greater than 10 years. Defining gross features of these masses included unilateral or bilateral diffuse thickening of the respiratory lining of the maxillary and/or frontal sinuses, with abundant seromucinous exudate in the affected sinus cavities. Defining histologic features of these masses included chronic inflammation and proliferation of mesenchymal and epithelial cells of the mucosa and submucosa. Epithelial changes included hyperplasia of mucosal epithelium, hyperplasia of submucosal glands and ducts, and neoplasia (adenocarcinoma). Mesenchymal changes included submucosal myxedema, submucosal fibroplasia/fibrosis, bone destruction, and neoplasia (myxomatous fibroma). Specific immunohistochemistry and polymerase chain reaction for Jaagsiekte sheep retrovirus and enzootic nasal tumor virus were performed with negative results.     

Experimental induction of malignant catarrhal fever in pigs with ovine herpesvirus 2 by intranasal nebulization

Malignant catarrhal fever (MCF), a frequently fatal herpesviral disease primarily of ruminant species, has been sporadically reported in pigs. All cases of naturally occurring porcine MCF reported to date have been linked to ovine herpesvirus 2 (OvHV-2), a gammaherpesvirus in the genus Macavirus carried by sheep. Experimental induction of MCF by aerosolization of the virus in nasal secretions collected from infected sheep has been successful in bison, cattle and rabbits. The goals of this study were to determine the susceptibility of pigs to MCF following experimental intranasal inoculation of OvHV-2, and to characterize the disease. Twelve pigs in four groups were nebulized with 10(5), 10(6), 10(7), or 10(8) DNA copies of OvHV-2 from sheep nasal secretions. Three control pigs were nebulized with nasal secretions from uninfected sheep. Three additional pigs were inoculated intravenously with 10(7) DNA copies of OvHV-2 to evaluate this route of infection with cell-free virus. Seven of twelve intranasally challenged pigs became infected with OvHV-2. Five of these seven, all in higher dose groups, developed MCF. Lesions resembled those reported in natural cases of porcine MCF. The most striking and consistent histological lesions were in trachea, lung, kidney and brain. These comprised mucopurulent tracheitis, interstitial pneumonia, necrotizing arteritis-periarteritis, and nonpurulent meningoencephalitis. No infection was established in the intravenously challenged or control groups. The study showed that MCF can be experimentally induced in pigs by aerosol challenge using sheep nasal secretions containing OvHV-2. Domestic pigs are a natural clinically susceptible host for sheep-associated MCF. They represent a useful, cost-effective model for MCF research.     

Pathology of enzootic intranasal tumor in thirty-eight goats.

Intranasal tumors were studied in 38 goats ranging from 7 months to 8 years of age of both Murciana-Granadina and crossed breeds. Tumors were diagnosed in eight herds. Clinically, the affected goats showed a copious seromucous nasal discharge, ocular protrusion, and skull deformations. The tumors originated from the ethmoid region. They involved one or both nasal cavities, although most were bilateral (26/38). The tumors were generally accompanied by inflammatory polyps. The histologic patterns were very similar in all cases, and the tumors were classified as low grade adenocarcinomas of the nasal glands. Histochemical, immunohistochemical, and ultrastructural studies suggested that the serous glands of nasal mucosa were the probable origin of the neoplastic cells. Budding and extracellular retrovirus-like particles were observed ultrastructurally in 6/8 tumors. The similarities between these caprine tumors and nasal tumors in sheep and the etiologic role of the retrovirus are discussed.     

Abomasal emptying defect of sheep may be an acquired form of dysautonomia

Abomasal emptying defect (AED) is a disease syndrome that primarily affects Suffolk sheep and is characterized by distension and impaction of the abomasum. No histologic lesion has been consistently associated with this condition. There is no known etiology. In this study, nine cases of AED were identified by necropsy, including three rams and six ewes between 2 and 6 years of age. Four of the cases occurred sporadically, and five ewes were submitted on the same day from a single flock. Histologic examination of celiacomesenteric ganglia from six of the affected sheep revealed scattered chromatolytic or necrotic neurons, without inflammation. Chromatolytic neurons were observed more frequently in AED-affected sheep than in seven healthy Suffolk sheep (P < 0.08, weak statistical support). Neuronal necrosis was not observed in any of the healthy sheep. Lineage records of the flock that suffered an outbreak were incompatible with the possibility of a simple inheritance pattern for this disease; furthermore, the very occurrence of AED in outbreak form is inconsistent with transmission solely by inheritance. Only one of the six tested sheep showed concurrent immunohistochemical evidence of scrapie. The lesion pattern in celiacomesenteric ganglia is suggestive of a neurotoxicosis. Neuronal lesions of AED resemble dysautonomic diseases of humans and other animals.     

The usefulness of immunohistochemistry to differentiate between nasal carcinoma and lymphoma in cats: 140 cases (1986–2000)

A retrospective evaluation of 232 feline nasal biopsies initially diagnosed as either carcinoma or lymphoma was performed by two pathologists. One or both pathologists disagreed with the original diagnosis in 15 cases (7%), 14 of which had original diagnoses of carcinoma. Out of the 232 cases, 140, including the disputed ones, were subjected to immunohistochemical staining with epithelial and lymphoid markers. Immunohistochemical staining of the 15 disputed cases showed that the original diagnoses were incorrect in 67% (10/15), unverified in 13% (2/15) and correct in 20% (3/15). Among the consensual diagnoses, immunohistochemistry revealed that 3% (4/125) of diagnoses were unverified because they did not stain for any of the markers evaluated. This report demonstrates the importance of immunohistochemistry in establishing a correct histologic diagnosis for nasal neoplasms in cats.     

Reservoirs of Staphylococcus aureus in meat sheep and dairy cattle

The objective of the study was to investigate reservoirs and transmission of S. aureus in ewes and lambs in 3 meat sheep flocks. Repeated sampling of milk, teat skin, nasal- and vaginal mucous membranes was performed and samples were analysed for S. aureus. For comparison, samples were also collected from cows and young heifers in 3 dairy cattle herds. Selected isolates were compared by pulsed-field gel electrophoresis (PFGE). S. aureus was detected in 8 (1.5%) of 520 milk samples from ewes and in 38 (6.4%) of 588 milk samples from cows. From body site swabs, S. aureus was found in 394 (32.6%) of 1208 samples from sheep and in 67 (16.0%) of 420 samples from cattle. The proportion of S. aureus-positive nasal swabs from ewes and cows were 56.7% and 13.9%, respectively. From lambs, 58.2% of the nasal swabs were S. aureus-positive. In each flock, one S. aureus pulsotype predominated. Identical S. aureus pulsotypes were found in milk and from body sites. Paired S. aureus isolates from the nasal cavity of (i) ewes and their lambs, (ii) twins and (iii) from repeated swabs of individual ewes were compared by PFGE, and in the majority of cases the two isolates were identical. The results contribute new knowledge indicating frequent transmission of S. aureus between the dam and her lambs and within animals in a flock. In contrast to cattle, S. aureus is frequently present in the nose of sheep which may represent the primary reservoir of S. aureus in sheep flocks.     

Prevalence of Taenia multiceps in sheep in northern Jordan

From March 1996 to February 1997, slaughtered-sheeps' heads were examined for the metacestode of Taenia multiceps. Out of 451 sheep heads, only 12 (3%) were infested. All cysts but one were in the age group 0.5-2.5 years old, with prevalence of 10% (11 of 108). Eleven of 12 infested heads were found during the spring and autumn seasons. Out of 95 flocks involved in questionnaire survey unrelated to the abattoir survey, all the farmers reported the existence of the clinical signs known for coenurosis and described it in locally known names and diseases. Twenty-five of them had recent cases that were diagnosed by the veterinarian as coenurosis cases. Each flock reported one or two cases at the time of survey. A variety of clinical signs were reported from these cases (n = 42). These included circling (86%), head pressing (52%), blindness (29%) and paresis (40%). Coenurosis is a sheep-health problem and an important cause of sheep culling in Jordan.     

Chronic Copper Poisoning in Sheep: Structural Changes in Erythrocytes and Organs

Four cases of experimental copper poisoning in sheep were examined. Light microscopical and ultrastructural alterations of erythrocytes were observed a few hours before a significant haemolysis was evident. Heinz body formation in otherwise unchanged red cells was the first morphological alteration observed. The Heinz bodies were predominantly membrane-attached. During the haemolytic crisis severe erythrocytic distortion, structural membrane alteration and Heinz body-containing ghost cells were observed. Erythrophagocytosis was mainly located to the RE cells of the spleen. Intrafollicular necroses were found in all histological sections from the spleen. Pathological changes in liver and kidney were comparable to those of earlier reports, comprising hepatocellular and renal tubular necrosis.     

Detection of enzootic nasal tumor virus (ENTV) in a sheep flock in southern Brazil

Enzootic nasal tumor (ENT) is a contagious neoplasm associated with enzootic nasal tumor virus (ENTV), which may induce disease in sheep (ENTV-1) and goats (ENTV-2). This study aimed to describe the occurrence of ENT in two Texel sheep (Ovis aries) from a 75-sheep flock, located in the city of Gravataí, southern Brazil. Animals used to be purchased from different origins, and no specific tests for disease monitoring or quarantine procedure were performed. Affected animals presented respiratory distress, anorexia with severe weight loss, and mucopurulent unilateral nasal discharge. Necropsy was performed in both animals and nasal cavity masses were observed. Histopathological analysis demonstrated an epithelial neoplasm compatible with nasal adenocarcinoma. PCR using a protocol that amplifies a 591 bp sequence of 5’LTR-gag region of ENTV1 was performed followed by DNA sequencing. Both samples were positive, and the sequences obtained presented highest identity (97%) with ENTV strain TN28 (GenBank accession number MH899613) detected in a Texel sheep from Scotland. This is the first report of ENTV-1 leading to enzootic nasal tumor in sheep in Latin America, which confirms the presence of the retrovirus in sheep flocks in the Brazilian territory.

     

Equine nasal cavity and paranasal sinus disease: A review of 85 cases

Eighty-five cases of equine nasal cavity and/or paranasal sinus disease (NC-PNSD) at Washington State University were reviewed with respect to incidence, clinical signs, treatment regimen and outcome. Incidence was 1.06 percent of all equine admissions over an 8-year period (July 1, 1977–June 30, 1985). For purposes of review, cases were divided into 6 groups depending upon etiology: 1. traumatic disorders, 2. developmental disorders, 3. neoplasia, 4. primary bacterial sinusitis, 5. sinusitis secondary to dental disorders, and 6. miscellaneous conditions.No correlation between sex or breed with NC-PNSD was identified. Traumatic and developmental disorders were most common in horses under 6-years-of-age and neoplastic conditions were most prevalent in horses over 10-years-of-age.The most common clinical signs of NC-PNSD, regardless of etiology were bony swelling or abnormalities noted externally, nasal discharge, and rhinodyspnea, followed by signs referrable to the oral cavity, external draining tracts, and epistaxis. All clinical signs were usually of a chronic duration (more than 2 weeks). Procedures which were most helpful in establishing a diagnosis were radiography (92% of cases), endoscopy (38%) sinocentesis (21 %), and examination of the oral cavity (20%).Of 74 horses available for follow-up, 49 were treated. Treatment was either not recommended or was declined by the owner in 12 cases, and euthanasia was performed without treatment in 13. Forty-six cases were treated surgically. The outcome of 23 of the cases was judged successful. Five had reduced clinical signs following surgery, and 18 were unsuccessfully treated. Those disorders judged to be traumatic in origin responded best to treatment while those involving neoplasia were the least successfully treated.     

Direct anthelmintic effects of condensed tannins towards different gastrointestinal nematodes of sheep: in vitro and in vivo studies

In vitro and in vivo studies were conducted to determine possible direct anthelmintic effects of condensed tannins towards different ovine gastrointestinal nematodes. A larval development/viability assay was used to investigate the effect of a condensed tannin extract (Quebracho) towards larvae of Haemonchus contortus, Teladorsagia circumcincta and Trichostrongylus vitrinus. The development to infective larvae and their viability was assessed in all three species and LD 50 values were calculated. The presence of Quebracho extract in the cultures decreased the viability of L3 in all species; the LD 50 were not significantly different for the different species. Forty-eight sheep were allocated to one of eight groups and were infected with a single dose of either 4000 L3 H. contortus (groups 1 and 2) or 5000 L3 T. colubriformis and 5000 L3 Nematodirus battus simultaneously (groups 3-6) or 10,000 L3 of T. circumcincta (groups 7 and 8). From day 28 until day 31 of the experiment, sheep infected with the intestinal species were drenched with Quebracho extract at 4, 8 or 16% w/w of food intake, or remained as undrenched controls; sheep infected with the abomasal species were either drenched with Quebracho extract at 8% w/w of food intake or remained as undrenched controls. All sheep were slaughtered 4 days after the end of the drenching period. Sheep infected with the intestinal species and drenched with 16% w/w Quebracho had lower FEC compared to sheep drenched with 8% w/w (P<0.05), which in turn were lower than in sheep either drenched with 4% Quebracho or which remained undrenched (P<0.05). The lowest intestinal worm burden was recovered from sheep drenched with 8% w/w Quebracho extract (P<0.05). The administration of Quebracho extract at 8% of food intake for 3 days did not affect FEC or worm burdens in sheep infected with the abomasal species compared to controls.     

CT findings in 20 dogs and six cats with confirmed nasal foreign bodies

The diagnosis and treatment of nasal foreign bodies usually includes a combination of rhinoscopy and imaging techniques, such as CT. The purpose of this retrospective, multicenter study was to describe the CT characteristics of nasal foreign bodies in dogs and cats and to determine if different nasal CT features exist between acute and chronic cases. Twenty dogs and six cats met the inclusion criteria. Eleven nasal foreign bodies (42%) were detected confidently with CT. The foreign body had a linear shape in 81% of cases and displayed a “tubular‐like appearance” in 54% of cases. In five cases (19%), a foreign body was suspected but not clearly visible. Additional CT changes were present in the nasal passages in 96% of the cases. The presence of turbinate destruction (P = .021) and mucosal thickening (P = .014) on CT were associated with the presence of a chronic nasal foreign body. In this sample, the nature of the foreign body did not influence its visibility and was not associated with specific CT characteristics. Computed tomography may be useful in the investigation of nasal foreign bodies, however, a negative CT examination does not exclude their presence.