Hematologic and radiographic changes in cats after inoculation with infective larvae of Dirofilaria immitis.

Hematologic and radiographic findings in 15 domestic cats inoculated with 25, 100, or 200 to 400 infective larvae of Dirofilaria immitis and in 5 uninoculated cats were compared. Eosinophilia and leukocytosis developed 3 to 5 months after inoculation; packed cell volume and hemoglobin values were similar for inoculated cats and controls. Changes detected in radiographs of inoculated cats were: (1) increased visualization of the pulmonary arteries; (2) right-side cardiac enlargement; and (3) diffuse to focal areas of density in the pulmonary parenchyma. At least one of these lesions was visible radiographically by 3 to 7 months after inoculation in all 15 cats. The severity of changes was not directly proportional to the number of infective larvae inoculated, adult worm burden, or age of cat. However, male cats had more severe cardiopulmonary lesions than did females, and cats that had microfilaremia during the course of infection had more severe pulmonary lesions, as determined radiographically. Parenchymal densities decreased in 8 of the 15 inoculated cats 6 to 14 months after inoculation. Cardiac enlargement was detected radiographically in 10 of the inoculated cats. Enlargement of the pulmonary arteries was the most consistent sign of D immitis infection; it developed and persisted in 12 cats found to be infected at necropsy.     

Comparison of concurrent imaging modalities for staging of dogs with appendicular primary bone tumours

This study assessed the use of whole body computed tomography (CT) for the evaluation of metastasis in dogs with primary appendicular bone tumours compared to long bone survey radiography, bone scintigraphy and thoracic radiographs. Fifteen dogs were included in this pilot study. A construct reference standard was used for detection of bone metastasis, and negative thoracic radiographs were compared against CT. Definitive lesions were only identified on bone scintigraphy. Not all lesions agreed with the construct reference standard. No definitive lesions were identified on survey radiographs or CT. Lesions were identified on thoracic CT that were not visible radiographically. Equivocal ground glass pulmonary lesions progressed in three of four cases. Whole body CT was not a suitable alternative to bone scintigraphy; however, it was useful as an adjunctive diagnostic modality. Pulmonary lesions were visible on CT that were not seen radiographically and ground glass pulmonary lesions in dogs should be considered suspicious for metastasis.     

Experimental infection of piglets by aerosols of Rhodococcus equi.

The purpose of this study was to investigate experimental infection of the piglet as a model of Rhodococcus equi pneumonia in the foal. Three litters of eight piglets each were exposed to an aerosol of 3.4 X 10(7) R. equi per piglet per day for seven consecutive days. Over the next 23 days the piglets were observed for clinical signs of disease. Periodically after infection one piglet from each litter was killed, the lungs were cultured quantitatively for R. equi and the gross and microscopic pulmonary lesions were assessed. The only clinical evidence of disease was the occurrence of elevated temperatures in the infected piglets. Rhodococcus equi was slowly cleared from the piglets' lungs during the 23 days following aerosolization. Piglets sacrificed seven to ten days after aerosolization had the most extensive pulmonary lesions, consisting of severe consolidation of the cranioventral lobes. Microscopic examination revealed thickened interalveolar septa and alveoli containing many neutrophils and macrophages with intracytoplasmic Gram-positive coccobacilli. The pulmonary lesions in these piglets differed from those of naturally infected foals in that they were not characterized by macrophage-rich abscesses and the infection gradually resolved.     

Life cycle of Frenkelia. IV. Pathomorphological findings in the organs of experimentally infected bank voles]

In 1975 the buzzard (Buteo buteo) was found to be the final host of Frenkelia clethrionomyobuteonis. After this discovery it became possible to investigate systematically the pathomorphology of the infection in the intermediate host, the bank vole (Clethrionomys glareolus). Fifty bank voles were infected orally with a suspension of sporocysts recovered from the faeces of experimentally infected buzzards. Each rodent receive 7000 sporocysts. Six controls each were given a faecal suspension from a non-infected buzzard. The voles were killed between 1 and 140 days after infection and examined histologically. Between the 5th and 8th day of the infection during the schizogonic multiplication of the parasite a focal necrosis of liver cells and of the liver parenchyma is observed followed by a reversible resorptive inflammation associated with siderophagia and the occurrence of giant cells. The spleen was spodogenously enlarged up to twice its normal size. There also was haemosiderosis of the bone marrow, the liver and the spleen up to 25 days after infection. At the same time the erythropoiesis in the bone morrow, the spleen and in the lymph nodes increased; there also was a lymphoid hyperplasia in spleen and lymph nodes. About 10 days after infection a reversible infiltration with lymphocytes and plasma cells developed in the liver, heart and brain. This infiltration was again detectable as perivascular and meningeal reactions in the brain after the 49th day after infection. The second asexual multiplication of the parasite was seen histologically in the grey and white matter of the central nervous system after the 18th day of infection. The developing cysts increased in size continuously thereby compressing the surrounding nervous tissue. Disseminated focal necrosis with resorptive inflammatory components was prominent in the parenchyma of the brain after the 49th day of infection. It was possible to differentiate between damage in single organs and systemic pathological lesions. The lesions in single organs were directly connected with the development of parasitic stages in the liver (schizonts) and in the brain (cysts). The generalized lesions occurred in the haemopoietic system after an impairment of the blood during the first asexual multiplication. They also occurred in the immunocytic systems after the first and during the second asexual multiplication and during the relatively late cystic phase of the parasite in the brain. The pathogenesis of the disintegration of blood cells is not clear. The immunocytic reaction can be considered an immunological response of the host against the parasite. The effect of the development of the cysts on the function and structure of the central nervous system is expected to lead to an increasing impairment of the motility of the intermediate host.     

Radiographic and radionuclide lung perfusion imaging in healthy calves and calves naturally infected with bovine respiratory syncytial virus.

Nine calves between three and 18 weeks old with serologically confirmed natural bovine respiratory syncytial virus infection were examined clinically, radiographically and by radionuclide lung perfusion imaging. The results were compared with those from seven healthy calves. The diseased calves were euthanased and examined pathologically, virologically and bacteriologically. The clinical signs indicated that the disease was in an acute stage. Radiography of the diseased animals revealed cysts, corresponding morphologically with bullous emphysema, and infiltrations roughly corresponding in distribution with atelectatic and, or, pneumonic areas. Radionuclide lung perfusion imaging revealed no perfusion shifts between the left and right lungs and a normal perfusion pattern in five of the nine diseased calves. The abnormalities in the perfusion patterns of three calves were probably caused by anatomical disorders such as cysts and pleural adhesions, but no cause of the abnormality could be found in one calf. These findings suggest that in calves infected with bovine respiratory syncytial virus, the normal perfusion pattern is maintained until anatomical disorders occur. The pathological examination and radiography revealed that the cranioventral lung fields were particularly poorly ventilated. This finding and the normal perfusion pattern indicate that these parts of the lungs are probably the sites where shuntings and perfusion-ventilation mismatchings occur.     

Staphylococcus aureus pneumonia in turkey poults with gross lesions resembling aspergillosis.

The present report describes a case of Staphylococcus (Staph.) aureus pneumonia in turkey poults. Initially, 3-day-old poults with a history of increased mortality were submitted for necropsy. The poults had severe bilateral consolidation of the lungs with miliary caseous nodules. The gross lesions in the lungs were highly suggestive of aspergillosis. The next day, postmortem examinations were performed on 60 dead poults at the farm, and all 60 had similar lung lesions. Histopathologic examination of affected lungs revealed severe subacute multifocal bronchopneumonia with intralesional bacteria. Tissue Gram stain of lung sections demonstrated gram-positive bacterial cocci. Gomori methenamine silver stain of the lungs failed to demonstrate fungal agents. The histologic distribution of the lesions suggested an aerogenous route of infection. Staphylococcus aureus was isolated in pure culture from affected lungs. Hatchery contamination was suspected because of the severity and early onset of the lesions. Bacterial monitoring at the hatchery demonstrated marked Staph. aureus contamination in two setters, a hatcher's air duct, and the poult room. Improved hatchery cleaning and disinfection prevented a reoccurrence of the problem.     

Pathogenesis of Marek's disease virus-induced local lesions. 1. Lesion characterization and cell line establishment

Subcutaneous (wing-web) or intramuscular inoculation of chickens with allogeneic normal or Marek's disease virus (MDV)-infected chicken kidney cells induced local lesions visible by 3-4 days postinoculation (PI). Lesions were slightly larger (P less than 0.05) in infected than uninfected chickens 5 and 8 days PI. They persisted and grew past 9 days PI only when infected. Infiltrating lymphocytes in infected and uninfected early lesions were similar; they included B-cells and also T-cells with and without Ia antigen. Up to 42% of lymphocytes from infected or uninfected lesions had the surface antigen MATSA. At 3 to 6 days PI, infected lesions contained lymphocytes with viral internal antigen, especially in Ia-bearing cells and MATSA-bearing cells, but thereafter infection was latent. Cells harvested daily from local lesions induced with allogeneic MDV-infected cells were cultured; MD tumor cell lines were established from lesions as early as 4 days PI, with a total success rate of about 50% thereafter. Either transformed tumor cells were already present during the early cytolytic infection period or else appropriate target cells were present that became infected in vivo and/or in vitro and then became transformed in vitro.     

Abattoir condemnation due to parasitic infections and its economic implications in the region of Trikala,Greece

The prevalence of parasitic infections responsible for the condemnation of carcasses and viscera during meat inspection, and their economic implication, was estimated in a year long abattoir survey of 10 277 slaughtered farm animals in the region of Trikala, Greece. The organs examined for the presence of parasitic lesions during meat inspection were: liver and lungs of all animals, rumen of cattle, small intestine of lambs and kids, and muscles of cattle and swine. The parasitic lesions observed in the lungs of cattle, sheep and goats were caused only by hydatid cysts. No hydatid cysts were observed in the lungs of swine. The parasitic lesions observed in the liver of cattle, sheep and goats were as a result of hydatid cysts and flukes of Fasciola hepatica and Dicrocoelium dendriticum, while those of swine were due to milk spots only. Moniezia sp. proglottids were found in the small intestine of lambs only. The prevalence of parasites responsible for the condemnation of marketable organs was low (0.26%). Parasites were responsible for 22% of the total of condemned organs, and their annual cost was 99, 00 GDR (approximately 292 Euros). The parasites most contributing to marketable organ condemnation were hydatid cysts (26%) and D. dendriticum flukes (26%).     

The prevalence and distribution of Mycobacterium bovis infection in European badgers (Meles meles) as determined by enhanced post mortem examination and bacteriological culture

The accurate diagnosis of Mycobacterium bovis infection in badgers is key to understanding the epidemiology of tuberculosis in this species and has significant implications for devising strategies to limit spread of the disease. In this study, badgers (n = 215) in the Republic of Ireland were examined at post mortem and tissues were collected from a range of anatomical locations and pooled into groups for bacterial culture of M. bovis. By assessing confirmed gross visible lesions (VL) alone, infection was detected in 12.1% of badgers. However, by including the results of all culture positive pooled samples, the overall infection prevalence increased significantly to 36.3%. Two-thirds (66.7%) of infected animals had no visible lesions (NVL). While the thoracic cavity (lungs and pulmonary lymph nodes) was found to be the most common site of infection, in a proportion of animals infection was absent from the lungs and draining lymph nodes and was confined to the lymph nodes of the carcase or the head. This may indicate an early extrapulmonary dissemination of infection or alternatively, in the case of the head lymph nodes, a secondary pathogenic pathway involving the lymphoid tissues of the upper respiratory tract (URT).     

T lymphocyte subset alterations following bluetongue virus infection in sheep and cattle

To determine potential mechanisms of differential disease expression in ruminants infected with bluetongue virus (BTV), clinically normal, BTV-seronegative, yearling sheep and cattle were infected subcutaneously with a standardized insect-source inoculum of BTV serotype 17 (BTV-17) (three infected and one contact control each) or animal adapted BTV serotype 10 (BTV-10) (three sheep only). BTV was isolated from peripheral blood cell components of infected sheep and cattle and all infected animals showed evidence of seroconversion by 14 days post infection (PI). Sheep infected with both serotypes of BTV developed pyrexia, oral lesions, and leukopenia which were most severe on days 7-8 PI. Analysis of peripheral blood mononuclear leukocytes with specific monoclonal antibodies and flow cytometry revealed panlymphocytopenia on day 7 PI. This response was further characterized by an increase in the CD4/CD8 ratio (greater than 3) resultant from a greater decrease in absolute numbers of circulating SBU-T8(CD8+) ("cytotoxic/suppressor") lymphocytes compared to SBU-T4 (CD4)+ ("helper") lymphocytes. SBU-T19+ lymphocytes were also decreased below baseline values on days 5-14 post infection. On day 14 PI there were increased CD8+ lymphocytes and decreased CD4/CD8 ratios (approximately 0.6) in these sheep. Clinical and hematologic changes in cattle infected with BTV-17 were minimal and consisted of mild pyrexia (rectal temperature 103 degrees F) on day 9 PI in two of three infected animals and mild leukopenia on several days PI in one animal. This leukopenia was the result of a pan T lymphocytopenia with CD4/CD8 ratios in the expected range (1-2). Similar to infected sheep, infected cattle did have a shift (decrease, approximately 0.8) in the peripheral CD4/CD8 ratio associated with an increase in circulating BoT8 (CD8)+ lymphocytes on day 14 post infection. Lymphocytes in the peripheral blood of all sheep and cattle infected with BTV-17 proliferated in vitro in response to purified BTV-17. These results confirm and extend those of previous studies that indicate species differences in the hematologic response to an equivalent BTV infection in domestic ruminants.     

Use of echocardiography for the diagnosis of heartworm disease in cats: 43 cases (1985-1997)

OBJECTIVE: To determine the usefulness of echocardiography in the diagnosis of heartworm disease in cats and to compare this modality with other tests. DESIGN: Retrospective study. ANIMALS: 43 cats with heartworm infection that had echocardiographic examinations at 2 veterinary teaching hospitals between 1985 and 1997. Twenty-two of these 43 cats also underwent radiography of the thorax and heartworm antibody and heartworm antigen testing. PROCEDURE: Cats were determined to be infected with Dirofilaria immitis infection on the basis of 1 or more of the following findings: positive modified Knott or antigen test result, echocardiographic evidence of heartworm disease, or confirmation of the disease on postmortem examination. The percentage of echocardiographs in which heartworms were evident was compared with the percentage of radiographs in which pulmonary artery enlargement was evident and results of antigen or antibody tests in cats in which all tests were performed. RESULTS: Overall, heartworms were detectable by use of echocardiography in 17 of 43 cats, most often in the pulmonary arteries. In the 22 cats in which all tests were performed, antibody test results were positive in 18, antigen test results were positive in 12, and pulmonary artery enlargement was evident radiographically and heartworms were identifiable echocardiographically in 14. Heartworm infection was diagnosed exclusively by use of echocardiography in 5 cats in which the antigen test result was negative. CONCLUSIONS AND CLINICAL RELEVANCE: Although echocardiography was less sensitive than antigen testing, it was a useful adjunctive test in cats that had negative antigen test results in which there was a suspicion of heartworm disease. The pulmonary arteries should be evaluated carefully to increase the likelihood of detection of heartworms echocardiographically.     

Prevalence of hydatidosis among donkeys in northern Jordan

One hundred and thirty donkeys (Equus asinus), aged between 5 months and 14 years of age, from the Irbid Governorate in northern Jordan were necropsied between November 1997-May 1999. Of these animals, 16.9% had hydatid cysts in either their lungs and/or livers. No donkeys of 3 years of age or less were infected, where as 33.3% (22 of 66) aged 4 years or greater were infected. Intensity of infection increased with age in a linear fashion. The prevalence also increased with age approaching an asymptotic prevalence of 1 in the oldest animals. This implied there was minimal regulation of the parasite population by intermediate host immunity. The numbers of cysts in the donkeys were increasing at a rate of 0.48 cysts per year from 0.054 infections. The frequency distribution was highly aggregated, consistent with a negative binomial distribution indicating infection of donkeys was not random.     

Abattoir Condemnation due to Parasitic Infections and its Economic Implications in the Region of Trikala,Greece

The prevalence of parasitic infections responsible for the condemnation of carcasses and viscera during meat inspection, and their economic implication, was estimated in a year long abattoir survey of 10 277 slaughtered farm animals in the region of Trikala, Greece. The organs examined for the presence of parasitic lesions during meat inspection were: liver and lungs of all animals, rumen of cattle, small intestine of lambs and kids, and muscles of cattle and swine. The parasitic lesions observed in the lungs of cattle, sheep and goats were caused only by hydatid cysts. No hydatid cysts were observed in the lungs of swine. The parasitic lesions observed in the liver of cattle, sheep and goats were as a result of hydatid cysts and flukes of Fasciola hepatica and Dicrocoelium dendriticum, while those of swine were due to milk spots only. Moniezia sp. proglottids were found in the small intestine of lambs only. The prevalence of parasites responsible for the condemnation of marketable organs was low (0.26%). Parasites were responsible for 22% of the total of condemned organs, and their annual cost was 99 500 GDR (～€292). The parasites most contributing to marketable organ condemnation were hydatid cysts (26%) and D. dendriticum flukes (26%).     

The pathology of experimental Corynebacterium equi infection in foals following intragastric challenge

The intragastric inoculation of a suspension of Corynebacterium equi on five consecutive days induced severe ulcerative colitis, typhlitis, and lymphadenitis of colonic and cecal nodes in two ponies necropsied three weeks after infection. No gross lesions were observed in two ponies necropsied ten days after infection. A single inoculum of equivalent size failed to induce gross lesions in four ponies killed at ten or 20 days after infection. Microscopic lesions consistent with early C. equi infection of Peyer's patches were seen in two of the ponies killed ten days after infection. Only one small pulmonary abscess occurred in one foal, suggesting that intestinal lesions are not likely the usual precursor of pulmonary disease in naturally infected foals. The gross and microscopic lesions in the experimentally infected ponies were typical of the intestinal form of naturally occurring C. equi associated disease in foals.     

Experimental infection of dexamethasone-treated goats with Pasteurella haemolytica A2.

Sixteen goats either subjected to transport stress or without transport stress were treated with dexamethasone for 3 days prior to infection with P. haemolytica serotype A2 intranasally. The transport-stressed and dexamethasone-treated goats in the first group had various degrees of pulmonary lesions and the organism was re-isolated from the nasal cavity, lymph nodes and lungs. None of the goats treated with dexamethasone only were infected with P. haemolytica and had no lesions of pneumonic pasteurellosis. Treatment with dexamethasone alone failed to induce experimental infection by P. haemolytica except in combination with another stress factor.     

Outbreak of disseminated zygomycosis and concomitant pulmonary aspergillosis in breeder layer cockerels

Disseminated zygomycosis and concomitant pulmonary aspergillosis were diagnosed in breeder layer cockerels. Five- to 9-week-old breeder layer cockerels with a history of an increased mortality rate were presented to a diagnostic laboratory for examination. On necropsy, large, multifocal, firm, tan, nodules were observed in the lungs, air sacs, peritoneum, livers, spleens and kidneys. On histopathology, mixed populations of zygomycetes and Aspergillus hyphae were observed in the granulomas in the lungs, and zygomycete hyphae were observed in the granulomas in the air sacs, peritoneum, livers, spleens and kidneys. No bacteria were isolated from any of the lesions. Aspergillus fumigatus was isolated from the lung lesions only and hyphae that were consistent with those of a Rhizopus spp. were isolated from the lesions in several organs. Pullets, which were kept together with the cockerels from the day they were hatched, were not affected. The absence of infection in the pullets, which were kept together with the cockerels, suggests that the cockerels were either infected during incubation, with the fungi penetrating the egg shell, or that they were infected during hatching before they were mixed with the pullets.     

Gross and histopathological studies on pulmonary lesions of camel (Camelus dromedarius) slaughtered at Addis Ababa abattoir,Ethiopia

This study was carried out with the aim of identifying types of gross and histopathological lesions in lungs of camels slaughtered between October 2009 and April 2010 at Addis Ababa abattoir enterprise, Ethiopia. All camels were originated from Borana and Kereyu areas. A total of 387 slaughtered camel lungs were inspected during the study period. Of which, one or more gross lesions were encountered on 300 lungs. Lesions were further subjected for detail gross and histopathological examinations. The occurrence of pulmonary lesions was 77.5%. The gross and histopathological examination of these lesions had revealed 60.2% emphysema, 21.2% hydatidosis, 18.6% pneumonia, 10.6% atelectasis, 4.9% aspiration of blood, 3.9% pneumoconiosis, 2.6% pulmonary edema and congestion, 1.6% abscess, 1% pleurisy, and 0.8% granulomatous pneumonia. Most camels had one or more pulmonary lesions on postmortem examination, but they were apparently healthy during antemortem inspection. Therefore, the prevailing stressful environmental condition coupled with the existing poor level of veterinary service in camel-rearing areas of the country might reverse these hidden inactive lesions and thereby contributed for the higher occurrence of respiratory diseases in camels.     

HYPERTROPHIC OSTEOPATHY ASSOCIATED WITH PULMONARY BLASTOMYCOSIS IN A DOG

Hypertrophic osteopathy (HO) associated with pulmonary blastomycosis was diagnosed in a 5–year-old male mixed-breed dog. One year prior to referral, increased pulmonary opacity had been identified on radiographs made during an examination for a chronic cough. Although serologic tests for blastomycosis were negative, the dog was treated with oral ketoconozole on the basis of suspicious lesions seen on radiographs and clinical signs. Ten months after completing the ketoconozole therapy, the dog was presented for a persistent cough and lameness. Intrapulmonary masses and periosteat proliferation were observed radiographically. A biopsy of the pulmonary masses was done, and Blastomyces dermatitidis was identified. Amphotericin B and ketoconozole administration resulted in clinical improvement and partial resolution of the HO lesions five months after initiation of therapy.     

Histopathology of the early phase during experimental Corynebacterium pseudotuberculosis infection in lambs.

Histological responses during experimental Corynebacterium pseudotuberculosis infection in lambs were investigated in parotid lymph nodes for ten days following inoculation. Lambs were infected by the subcutaneous route into the right eyelid with a virulent strain of C. pseudotuberculosis. Multiple microscopic acute abscesses, predominantly infiltrated with polymorphonuclear (PMN) leucocytes, were seen in the right parotid lymph node on the 1st day post-inoculation (PI). This massive PMN infiltration coincided with a peripheral blood granulocytosis. On day 3 PI, an influx of histiocytes was observed, while the microabscesses became confluent. From day 3 to day 10 PI, these lesions became enlarged and transformed into typical pyogranulomas with a central necrosis and a peripheral mantle of mononuclear cells composed of macrophages, epithelioid cells and lymphocytes; these histological changes were associated with a bacterial dissemination limited to the superficial lymph nodes. A lymphoid hyperplasia with prominent germinal centers was observed in the draining lymph nodes from day 3 PI. These results illustrate the dual role of granulomatous lesions in chronic bacterial infections: although they limit bacterial dissemination, the granulomas do not impair the persistence of infectious organisms in the host, leading to focal tissue damage.     

Survival, immune responses and tissue cyst production in outbred (Swiss white) and inbred (CBA/Ca) strains of mice experimentally infected with Neospora caninum tachyzoites

The present work compared inbred (CBA/Ca) and outbred (Swiss white) strains of mice for their capacity to cope with a Neospora caninum infection and to consistently produce tissue cysts. In each experiment Swiss white and CBA/Ca mice were given three different doses of NC-1 tachyzoites. Lymphoproliferative and humoral responses as well as cytokine production were evaluated eight weeks after infection (PI) whereas tissue cyst production and histopathology were assessed 4, 6 and 10 weeks PI in immunosuppressed mice. Tissue cysts were observed 10 weeks after infection only in CBA/Ca mice receiving the two highest inoculum doses. Furthermore this strain showed the highest specific lymphoproliferative response. A mixed cytokine response with elevated IFN-gamma and fairly low IL-4 and IL-10 secretion was recorded. In both strains, no lesions were observed in the tissues of infected mice. This study indicates that CBA/Ca female mice infected with 5 x 10(6) NC-1 tachyzoites represent a useful model for the study of specific maternal immune responses in pregnant animals.