N. Toplu

Dual Infection of Fetal and Neonatal Small Ruminants with Border Disease Virus and Peste des Petits Ruminants Virus (PPRV): Neuronal Tropism of PPRV as a Novel Finding

Dual infection of 26 fetal and neonatal small ruminants with border disease virus (BDV) and peste des petits ruminants virus (PPRV) is reported. The animals included five aborted lamb fetuses, 19 neonatal lambs and two neonatal kids from flocks in regions of the Black Sea and the Aegean region. BDV and PPRV antigens were detected immunohistochemically in the brain, oral mucosa, intestine and lung of infected animals. Reverse transcriptase-polymerase chain reaction was used to demonstrate PPRV and BDV in samples of the spleen, lymph node, lung and brain from infected animals. On the basis of observations made, it is concluded that brain damage following intrauterine infection with BDV facilitates the passage of PPRV to the brain and results in infection of neuronal and glial cells by PPRV.

An immunohistochemical study in cases with usual and unusual clinicopathological findings of canine visceral leishmaniosis

The present study describes pathologic findings and immunohistochemical diagnosis of canine visceral leishmaniasis (CVL) in 22 dogs who died naturally in the Aegean region of Turkey. At necropsy, lymphadenomegaly, hepatosplenomegaly, hepatic, and nephrosclerotic lesions were conspicuous. Histopathologically, chronic inflammatory reactions of the spleen, lymph nodes, bone marrow, liver, and skin were marked findings. Cytological and histological examinations showed macrophages loaded with Leishmania amastigotes in these organs. Immunohistochemistry revealed that immunolabeling of amastigotes and/or parasite antigen, especially in the lymph nodes, spleen, bone marrow, liver, and skin, and occasionally, in the kidneys, intestines and lungs. Our laboratory results showed that immunohistochemistry should be included, along with cytological and histological examinations, in the diagnosis of CVL.

Neuropathologic Study of Border Disease Virus in Naturally Infected Fetal and Neonatal Small Ruminants and Its Association With Apoptosis

The present study describes the pathologic changes and cellular apoptosis in the central nervous system (CNS) of fetal and neonatal small ruminants infected with border disease virus (BDV), as demonstrated by immunohistochemistry and in situ hybridization. Abortions of ewes and goats were observed, as were births of lambs and kids with poor survival rates and nervous signs. Lesions included cerebellar hypoplasia, porencephaly, hydranencephaly, and nonsuppurative meningoencephalomyelitis with hypomyelinogenesis. Viral antigens and RNA were present in neuropil, glial, and neuronal cells, especially in periventricular areas, cerebellum, and brainstem. TUNEL positivity and labeling of anti-bax and anti-caspases 3, 8, and 9 were detected in BDV-infected CNSs, especially in glial and neuronal cells. The double immunostaining and TUNEL assay revealed that in BDV-infected animals, not only were BDV-infected glial and neuronal cells undergoing apoptosis, but so were uninfected cells in close vicinity of BDV-infected cells. The expression of activated caspases 3, 8, 9; bax; and TUNEL in glial and neuronal cells of the infected fetal and neonatal kids were significantly (P < .05) higher than those of the infected fetal and neonatal lambs. Yet, the expression of bcl-2 in the CNSs of the infected fetal and neonatal lambs was higher (P < .05) in neuronal and glial cells than in those of the infected fetal and neonatal kids. The results suggest that cell death in the BDV-infected CNS is induced by intrinsic and extrinsic cascades of apoptotic pathways.

Avian encephalomyelitis in naturally infected pigeons in Turkey

The pathological and immunohistochemical findings of avian encephalomyelitis (AE) were described in various tissues of naturally infected pigeons of a flock from a outbreak in Turkey. Clinically, paresis, paralysis, circling movement and torticollis of the head associated with nervous signs were marked symptoms among the diseased pigeons. At necropsy, small or large white–greyish foci were detected in the pancreas, and erosive-ulcerative foci along with petechial hemorrhages in ingluves. Histopathologically, lesions in central nervous system, particularly in the cerebullum molecular layer, consisted of non-suppurative encephalomyelitis. Lesions in the pancreas revealed non-suppurative pancreatitis along with acinar degeneration and necrosis and/or lymphoid aggregations. Immunohistochemical staining of formalin-fixed, paraffin-embedded tissues was performed using a direct-fluorescein antibody technique with chicken anti-AE virus serum flourescein isothiocyanate conjugate. Viral antigen was strongly stained in cytoplasm of epithelial cells of the exocrin glands, and neurons of the cerebral hemispheres and midbrain. In addition, viral antigen was also marked in the kidneys and tissues of the digestive system. Consequently, this article is, to our knowledge, the first report of natural AE in pigeons.

West Nile Virus Infection in Horses: Detection by Immunohistochemistry, In Situ Hybridization, and ELISA

This study describes the clinicopathologic findings in naturally occurring West Nile virus (WNV) infection in horses. WNV was diagnosed in a foal by immunohistochemical and in situ hybridization methods, and the presence of WNV antibodies was detected in 5 other horses with clinical signs suggestive of WNV infection. At necropsy of the foal, lymph nodes were edematous and enlarged, and the intestines showed diffuse congestion and focal hemorrhages. The most significant histologic lesions in this case were nonsuppurative meningoencephalomyelitis, particularly in the brainstem and spinal cord. Identification of viral RNA by in situ hybridization and viral antigen by immunohistochemistry was concentrated primarily in nerve fibers, glial cells, and their processes in brainstem and spinal cord and, to a lesser extent, within the cerebral hemispheres and cerebellum.

Pathomorphological, immunohistochemical and bacteriological findings in budgerigars (Melopsittacus undulatus) naturally infected with S. Gallinarum

The present study describes the pathological and bacteriological findings and diagnosis by immunoperoxidase and immunofluorescence methods in budgerigars (Melopsittacus undulatus) naturally infected with Salmonella gallinarum obtained from three commercial budgerigar rearing farms. The course of the disease in young budgerigars was peracute or acute, whereas in adult budgerigars the disease was acute or chronic. Clinically, yellow–white diarrhoea was observed in the young budgerigars with the acute form. In the adult budgerigars with the acute and chronic forms, a decrease in feed and water consumption with loss in body condition together with greenish-yellow diarrhoea was generally noted. Peritonitis and pericarditis were the most common findings in young budgerigars at necropsy, while in adult budgerigars scattered grey–white necrotic foci were found in the livers. Histopathologically, the lesions in young budgerigars were characterized with fibrinonecrotic peritonitis and/or pericarditis and necrotic hepatitis. In adult budgerigars with acute infection, hepatic necrosis with focal heterophil infiltration was present; whilst lesions in the chronic cases were granulomatous in nature with the infiltration of macrophages, lymphocytes and histiocytes. For the detection of S. Gallinarum in formalin-fixed, paraffin-embedded tissues, the avidin–biotin peroxidase complex and immunofluorescence methods were used. Both methods showed bacteria to be localized in the liver, kidney, peritoneum, heart, spleen and intestines of both young and adult budgerigars. The results of the present study indicate that the avidin–biotin peroxidase complex method was more sensitive than the immunofluorescence method in the detection of the bacteria.

First molecular detection and characterization of Akabane virus in small ruminants in Turkey.

Abortion outbreaks associated with congenital malformations in two distinct small-ruminant flocks were reported in Turkey in 2013-2014. This paper describes the first molecular characterization of Turkish Akabane virus strains in small-ruminant flocks using partial sequence analysis of the S segment and pathological findings.

Author’s Responses to Dr Del Piero’s Critique

Critique 1. Regarding the staining method in Figure 3. Response: Please see the editor’s note. Critique 2. Regarding the specificity of the clinical signs. Response: Absolutely, clinical signs described were not specific for WNV and also could be seen in other infectious diseases with brain lesions. Consideration of the clinical signs for a pathologist are one of the diagnostic steps. In this article, diagnosis of WNV was confirmed by ISH and IHC together with histopathological changes. Critique 3. Regarding the endothelia and periendothelial staining and the specificity of the staining. Response: We repeated our test and had similar results. Figure 2 is clear and includes cytoplasmic granular labeling in neurons and glial cells, while the nonspecific neuropil staining represents background staining. In addition, a recent report on WNV from Turkey reported that IHC showed marked vascular localization of WNV antigen (‘‘Perinatal West Nile Virus Infection in a Foal in Turkey,’’ Özkul et al, presented at the 9th annual meeting of Epizoone, 2015, p 242). Our result and this result indicate that vascular localization and the abundant presence of antigen could be associated with WNV circulating in Turkey. Critique 4. Regarding the cross-reaction of the competitive ELISA kit with Japanese encephalitis viruses and the tickborne encephalitis virus. Response: Absolutely, the immunological methods with polyclonal antibody could show cross-reaction with Japanese encephalitis and tick-borne encephalitis. However, the ISH methods with specific probes confirmed WNV in the foal of this article.