Semsettin Ustacelebi

Diagnosis of herpes simplex virus infections

Herpes simplex virus (HSV) infections of humans have been recognized since ancient times. Two biologically distinct serotypes, HSV type 1 (HSV-1) and HSV type 2 (HSV-2) were identified (Rawls, 1985) and the serological techniques with various specificity and sensitivity were developed to identify HSV infections in order to understand epidemiology and pathogenesis of these infections in human host (Wentworth et al., 1971; Corey et al., 1983; Whitley, 1990). The prevalence of HSV1 infections increases gradually from childhood, reaching up to 80–90% in adult age. However HSV-2 infections are sexually acquired, so its incidence begins to increase in adolescence (Whitley, Johnson et al., 1989). The prevalence rates for HSV-2 infections range from about 20–60% in various countries. In general, primary HSV-1 and HSV-2 infections are entirely asymptomatic. As with most herpesvirus family members initial infections with HSV-1 and HSV-2 results in establishment of viral latency. Under certain circumstances both viruses are reactivated from the latent state and cause symptomatic infections. The classical manifestation of primary HSV-1 infection is called herpes gingivostomatitis. Gingivostomatitis is characterized with painful vesicular lesions of the oral mucosa, particularly of gingiva with a high temperature and submandibular lymphadenopathy. Conjunctivitis, keratitis, herpetic whitlow and sporadic acute necrotizing encephalitis are the other clinical manifestations of HSV-1 infection. Encephalitis occurs in older children and adults with high mortality if not treated (Whitley, 1988). HSV-2 infections are manifested as herpes genitalis and infection is characterized by the appearance of extensive, bilaterally located ulcers in genitalia accompanied by fever, inguinal lymphadenopathy and dysuria (Corey et al., 1983). Approximately 85% of primary symptomatic HSV genital infections are caused by HSV-2. HSV-1 only contributes 15% of the primary genital infections. However, most of the recurrent genital infections are due to HSV-2 (Gleaves et al., 1985). Most primary infections with HSV-1 and HSV2 do not manifest characteristic clinical disease and are almost entirely asymptomatic and followed by latent infection of neuronal cells in the trigeminal and dorsal root ganglia. HSV-1 and HSV-2 are classified in the alphaherpesvirus subfamily of herpesviruses (Roizman and Batterson, 1985). All herpesviruses are morphologically similar. They have icosahedral capsids containing 162 capsomers enclosing a core structure containing double-stranded linear viral DNA. Complete virion mature by budding off through the nuclear membrane acquiring phospholipid-rich viral envelope. The space between viral capsid and envelope is called viral tegument

West Nile virus studies in the Sanliurfa Province of Turkey

ABSTRACT We attempted to isolate West Nile virus from mosquitoes collected in the field for the first time in Turkey. A total of 6, 457 mosquito specimens from Culex pipiens Linnaeus, Ochlerotatus caspius (Pallas) and Aedes spp. species were included in this study. Culex pipiens samples made up 56% of the total species, O. caspius 24% and Aedes spp 20%. There were no positive results after studying mosquito samples using Real-time PCR, VecTest, and Vero cell culture. In serological tests of 181 human serum samples, 29 (16%) were found to be West Nile positive. On the basis of these results, we intend to collect more mosquito samples especially from those areas from which positive serum samples were obtained.

Testicular persistence of Parvovirus B19: evidence for preferential infection of germ cell tumors.

Human Parvovirus B19 has previously been implicated in the pathogenesis of testicular germ cell tumors, but this could not have been confirmed. This study was designed to investigate the testicular persistence of Parvovirus B19 and possible associations with germ cell tumors. Paraffin-embedded or fresh tissues from 36 germ cell tumors, 20 germ cell aplasias, 26 normal testicular tissues, 20 liver tissues, and 20 spleen tissues were evaluated by two different molecular assays: a nested PCR for Parvovirus B19 capsid genes and a commercial quantitative real-time PCR. Positive results were further confirmed by another commercial real-time PCR assay. Viral DNA was detected in 3 of 36 (8.3%) germ cell tumors, but not in other groups. Viral loads observed in all positive samples were less than 20 IU/reaction, suggesting very low levels of viral replication or latency. These results either directly or indirectly imply the involvement of Parvovirus B19 with testicular germ cell tumors. Viral persistence in normal testis, germ cell aplasia tissues, or hepatic/splenic tissues was not observed in this study.

TRANSFUSION-TRANSMITTED VIRUS PREVALANCE IN TURKISH PATIENTS WITH THALASSEMIA

In hematology patients on chronic transfusion regimes, liver diseases are frequent, and mostly related to the agents transmitted by blood products and concominant iron deposition in liver. Besides hepatitis B (HBV) and C (HCV) viruses, new viral agents like hepatitis G virus (HGV) and TorqueTeno virus (TTV) are identified in these patients, although their association with any pathology or disease is not yet proved. In the present work, the authors studied the clinical importance of TTV in Turkish multitransfused patients with thalassemia. Forty-six healthy and 57 thalassemic patients were enrolled in the study. TTV was detected in serum samples by 3′-UTR nested PCR. Transaminase and ferritin levels, hepatitis B and C virus markers and number of transfusions were interpreted for possible association with TTV infection. As a result, TTV was detected in 63% of the thalassemia and 54% of the control patients. Prevalence of TTV infection, clinical features, laboratory data, and annual transfusion numbers of TTV-positive and -negative patients were not observed to be statistically significant. In conclusion, in Turkish patients with thalassemia, TTV infection cannot be considered as a risk factor for liver disease.

Identifying the etiologic role of Parvovirus B19 in non-immune hydrops fetalis by histopathology, immunohistochemistry and nucleic acid testing: a retrospective study

Intrauterine Parvovirus B19 infections may cause fetal anemia, non-immune hydrops fetalis or abortion. This study focuses on the pathogenic role of Parvovirus B19 in non-immune hydrops fetalis at Hacettepe University, a major reference hospital in Turkey. Twenty-two cases of non-immune hydrops fetalis were retrospectively selected out of a total of 431 hydrops fetalis specimens from the Department of Pathology archieves. Paraffine embedded tissue sections from placental and liver tissues from each case were evaluated by histopathology, immunohistochemistry, nested PCR and commercial quantitative Real-time PCR. Viral DNA was detected in placental tissues by Real-time PCR in 2 cases (2/22, 9.1%) where histopathology also revealed changes suggestive of Parvovirus B19 infection. No significant histopathologic changes were observed for the remaining sections. Nested PCR that targets the VP1 region of the viral genome and immunohistochemistry for viral capsid antigens were negative for all cases. As a result, Parvovirus B19 is identified as the etiologic agent for the development of non-immune hydrops fetalis for 9.1% of the cases in Hacettepe University, Turkey. Real-time PCR is observed to be an effective diagnostic tool for nucleic acid detection from paraffine embedded tissues. Part of this study was presented as a poster at XIIIth International Congress of Virology, San Francisco, USA (Abstract V-572).

Performance of three PCR methods targeting different regions of viral genome for the detection of TTV in Non A-E hepatitis, chronic B and C hepatitis and healthy blood donors

TT virus (TTV) was suggested to be the etiologic agent for non A-E hepatitis but this could not yet be proven due to high detection rates not only in hepatitis but also in healthy persons and sensitivity differences of PCR methods employed. The aim of this study was to evaluate TTV DNA positivity in non A-E hepatitis cases, chronic HBV and HCV hepatitis cases and healthy blood donors via PCR systems that target all regions of the viral genome used for viral detection. 23 non A-E hepatitis, 28 chronic HCV, 21 chronic HBV cases and 56 healthy blood donors were included in the study and evaluated by PCR protocols that target 5′-UTR, 3′-UTR and N22 (ORF1) regions. As a result, 3′-UTR and 5′-UTR PCR had comparable detection rates that were higher than N22 PCR. Differences in detection rates among study groups were not statistically significant for any PCR method. Hepatic enzyme levels of the patients were not correlated with the presence of TTV DNA. Detection rate was significantly higher for Non A-E hepatitis group when positivity rates from all methods were combined. These results suggest an alteration of viral genotypes in Non A-E hepatitis which might be associated with pathogenesis.