Marta Torres Santo Domingo

Identification of porcine circovirus in tissues of pigs with porcine dermatitis and nephropathy syndrome

Thirty-three pigs affected by porcine dermatitis and nephropathy syndrome, 30 from Spain and three from the USA, were investigated in order to detect porcine circovirus (Pcv) in their tissues. A standard in situ hybridisation technique using a specific DNA 317-bp probe based on a well-conserved sequence of Pcv (which recognises both Pcv-i and PCV-2) was applied to formalin-fixed, paraffin-embedded tissues. Twentyeight of the 30 Spanish pigs and all three American pigs had Pcv in at least one tissue. Viral nucleic acid was detected mainly in lymphoid organs, and especially the lymph nodes. The viral genome was also found, in order of decreasing quantity, in Peyers patches, tonsil, lung, spleen, kidney, liver, and skin. Viral nucleic acid was located mainly within the cytoplasm of monocyte/macrophage lineage cells, including follicular dendritic cells, macrophages, histiocytes and Kupffer cells. No viral nucleic acid was found in damaged glomeruli or arteriolar walls. In frozen samples available from three Spanish pigs, the virus was identified as type 2 by using the polymerase chain reaction and restriction fragment length polymorphism. Most of the pigs from which serum was available were seropositive against porcine respiratory and reproductive syndrome virus (PRRSV), and PRRSV antigen was detected in the lung of two of the Spanish pigs. These results suggested that Pcv is present in tissues of almost all pigs affected by PDNS, and Pcv has to be considered as a possible agent involved in the pathogenesis of the syndrome.

First report of post-weaning multisystemic wasting syndrome in pigs in Spain

Surgery or cryosurgery is one of the most common treatments for squamous cell carcinoma (Kwa and others 1992, Withrow and Madewell 1996). However, in the flock studied the location of the tumour on the eyelid rendered this type of treatment unsuitable. Bovine squamous cell carcinoma are responsive to immunotherapy, which results in the complete or partial regression of the tumours in the majority of cases (Spradbrow and others 1977). However, the application of immunotherapy to the condition in sheep has so far proved negative, and has resulted in the enhancement of tumour growth and -an increased risk of metastasis (Jun 1978, Jun and others 1979, Swan and others 1983). Chemotherapy with cyclophosphamide (200 mg weekly for 10 weeks) induced the partial or complete regression of the early lesions in a flock of sheep (Jun and Johnson 1979); the treatment was subsequently recommended for all the sheep in the flock with early lesions, but owing to the cost, the owner decided not to apply it. The clinical and pathological characteristics of the outbreak of squamous cell carcinoma described here suggest that the breed of sheep, its lack of skin pigmentation, the farms southern latitude, and factors related to the type of farming played a decisive role in the development of squamous cell carcinoma in these sheep.

Hepatitis and staging of hepatic damage in pigs naturally infected with porcine circovirus type 2.

A total of 100 liver samples from pigs with postweaning multisystemic wasting syndrome (PMWS) were studied. All livers were evaluated microscopically and were staged based on the severity and localization of lesions. Presence of porcine circovirus type 2 (PCV-2) was evaluated using an in situ hybridization technique. Eighty-eight of 100 livers (88%) had a variable degree of lymphohistiocytic hepatitis, with apoptotic bodies, disorganization of hepatic plates, and/or perilobular fibrosis. Twelve pigs did not have microscopic liver lesions. Four stages of hepatic damage were established based on intensity and distribution of the lesions. Viral nucleic acid was detected in 70 of 100 livers (70%). Target cells for PCV-2 infection included Kupffer cells, hepatocytes, and inflammatory infiltrates. According to distribution of PCV-2 nucleic acid, four basic labeling patterns were identified. This study shows that liver damage is a frequent microscopic finding in cases of PMWS and hepatocytes are a target cell for PCV-2 infection and replication. Therefore, PCV-2 should be considered a new hepatitis-inducing viral agent in pigs.

AUJESZKY'S DISEASE VIRUS INFECTION CONCURRENT WITH POSTWEANING MULTISYSTEMIC WASTING SYNDROME IN PIGS

BROWNLIE, J., BOOTH, P. J., STEVENS, D. A. &COLLINS, M. E. (1997) Expression ofnon-cytopathogenicbovineviraldiarrhoea virus (BVDV) in oocytes and follicles of persistently infected cattle. Veterinary Record 141, 335-337 HAFEZ, S. M. & LIESS, B. (1972) Studies on bovine viral diarrhea-mucosal disease virus. II. Stability and some physico-chemical properties. Acta Virologica 16, 399-408 HOUE, H. & MEYLING,A. (1991) Prevalence of bovine virus diarrhoea (BVD) in 19 Danish dairy herds and estimation of incidence of infection in early pregnancy. Preventive Veterinary Medicine 11, 9 HOWARD, C. J., BROWNLIE, J. & THOMAS, L. H. (1986) Prevalence of bovine virus diarrhoea viraemia in cattle in the UK. Veterinary Record 119, 628 IETS (1990) Manual of the International Embryo Transfer Society. 2nd edn. Eds D. A. Stringfellow, S. M. Seidel. Champaign, Illinois, IETS PARRISH, J. J., SUSKO-PARRISH, J., LEIBFRIED-RUTLEDGE, M. L., CRITSER, E. S., EYESTONE, W. H. & FIRST, N. L. (1986) Bovine in vitro fertilization with frozen-thawed semen. Theriogenology 25, 591-600 PERONA, R. M. & WASSARMAN, P. M. (1986) Mouse blastocysts hatch in vitro by using a trypsin-like protease associated with the cells of mural trophectoderm. Developmental Biology 114, 42-52 SINGH, E. L., EAGLESOME, M. D., THOMAS, F. C., PAPP-VID, G. & HARE, W. C. D. (1982) Embryo transfer as a means of controlling the transmission of viral infections., I. The in vitro exposure of preimplantation embryos to akabane, bluetongue andbovine viral diarrhea viruses. Theriogenology 17,437-444 STRINGFELLOW, D. A. & WRATHALL, A. E. (1995) Epidemiological implications of the production and transfer of IVF embryos. Theriogenology 43, 89-96 VANROOSE, G., NAUWYNCK, H., VAN SOOM, A., VANOPDENBOSCH, E. & DE KRUIF, A. (1998) Replication of cytopathic and noncytopathic bovine viral diarrhea virus in zona-free and zona-intact in vitro-produced bovine embryos and the effect on embryo quality. Biology ofReproduction 58,857-866

Porcine dermatitis and nephropathy syndrome in Spain

In August 1995, the first case of porcine dermatitis and nephropathy syndrome was diagnosed in the north-eastern part of Spain; the pig showed characteristic dermal and renal lesions. Between then and January 1996, nine further animals from five different herds were diagnosed; they showed signs of anorexia, depression and, sometimes, pyrexia. Diarrhoea, Glässers disease, conjunctivitis and gastric ulcers also occurred on the farms where the diagnoses were made. The affected pigs died of renal failure with diffuse fibrinous glomerulonephritis and a systemic necrotising vasculitis. Chronic interstitial nephritis, glomerulosclerosis and scar-like marks on the skin were observed in chronic cases. Other common findings in both acute and chronic cases were a diffuse depletion of lymph node lymphocytes with infiltration by syncytial cells (50 per cent of cases) and interstitial pneumonia. All the animals tested positive for porcine reproductive and respiratory syndrome virus (PRRSV) by serological tests and virus isolation. Serum urea and creatinine concentrations were above normal in the acutely affected animals. The pathogenesis of the condition is unknown but the lesions and immunopathological observations by other authors suggest that a type III hypersensitivity is a possible aetiology. The occurrence of PRRSV in these pigs suggests that the virus might be implicated in the pathogenesis of porcine dermatitis and nephropathy syndrome.

Granulomatous Enteritis and Lymphadenitis in Iberian Pigs Naturally Infected with Lawsonia intracellularis

Intestinal samples and/or lymph nodes of two Iberian pigs from two different farms were submitted for histopathologic examination. Both pigs had proliferation of ileal and/or cecal crypts with almost complete absence of goblet cells. Infection by Lawsonia intracellularis was demonstrated by immunohistochemistry and polymerase chain reaction assay. The mesenteric lymph node of one pig had moderate lymphocyte depletion with granulomatous inflammation of the lymph node parenchyma. Histiocytes and multinucleated giant cells from the lymph node of one pig contained L. intracellularis antigen within the cytoplasm. This pig had also porcine circovirus type 2 (PCV-2) infection, but nucleic acid and antigen of this virus were not demonstrated in the lymph node. The second pig had lymphocyte depletion and marked granulomatous inflammation in Peyers patches. Histiocytes and multinucleated giant cells in areas of granulomatous inflammation contained L. intracellularis antigen; no PCV-2 nucleic acid or antigen was detected in the tissues of this pig. This is the first description of granulomatous ileitis and lymphadenitis associated with L. intracellularis infection.

Feline infectious peritonitis in servals (Felis serval)

FELINE infectious peritonitis (FHP) has been described both in domestic and exotic cats (Barlough and Stoddart 1990). In captive exotic felines, FHP had been only sporadically documented until an outbreak of FiP and other coronavirus-associated diseases was recorded as the cause of death in 18 of 35 cheetahs (Acinonyx jubatus) in a wildlife reserve in the early 1980s (Evermann and others 1983). Fatal FIP was also reported in three wild-caught cheetahs nine weeks after capture (Van Rensburg and Silkstone 1984). The incidence of FIP in the captive cheetah population has since decreased (Evermann and McKeirnan 1991) but there has been at least one further outbreak causing two deaths (Munson 1993). Recently, FIP has been recognised as the cause of death in five of eight captive adult European wildcats (Felis silvestris)