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Abstract Background Visceral leishmaniasis (VL) is a protozoan diseases caused in Europe by Leishmania (L.) infantum. Asymptomatic Leishmania infection is more frequent than clinically apparent disease. Among HIV infected patients the risk of clinical VL is increased due to immunosuppression, which can reactivate a latent infection. The aims of our study were to assess the prevalence of asymptomatic L. infantum infection in HIV infected patients and to study a possible correlation between Leishmania parasitemia and HIV infection markers. Methods One hundred and forty-five HIV infected patients were screened for the presence of anti-Leishmania antibodies and L. infantum DNA in peripheral blood. Statistical analysis was carried out by using a univariate regression analysis. Results Antibodies to L. infantum were detected in 1.4% of patients. L. infantum DNA was detected in 16.5% of patients. Significant association for PCR-Leishmania levels with plasma viral load was documented (p = 0.0001). Conclusion In our area a considerable proportion of HIV infected patients are asymptomatic carriers of L. infantum infection. A relationship between high HIV viral load and high parasitemic burden, possibly related to a higher risk of developing symptomatic disease, is suggested. PCR could be used for periodic screening of HIV patients to individuate those with higher risk of reactivation of L. infantum infection.

To the Editor: During the early 20th century, at the end of World War I, and during World War II, louseborne relapsing fever (LBRF) caused by Borrelia recurrentis was a [...]

To the Editor: The number of new rickettsial species that cause diseases in humans is rapidly increasing (1). Moreover, many of the species first described in ticks have been recently [...]

To the Editor: Mediterranean spotted fever (MSF) is endemic in Italy, where it is a reportable disease. From 1992 to 1998, the Italian Ministry of Health was notified of approximately [...]

Background: Imported cases of infections due to Dengue (DENV) and Chikungunya (CHIKV) viruses and, more recently, Zika virus (ZIKV) are commonly reported among travelers returning from endemic regions. In areas where potentially competent vectors are present, the risk of autochthonous transmission of these vector-borne pathogens is relatively high. Laboratory surveillance is crucial to rapidly detect imported cases in order to reduce the risk of transmission. This study describes the laboratory activity performed by the National Reference Laboratory for Arboviruses (NRLA) at the Italian National Institute of Health in the period from July 2014 to October 2015.Methods: Samples from 180 patients visited/hospitalized with a suspected DENV/CHIKV/ZIKV infection were sent to the NRLA from several Italian Hospitals and from Regional Reference Laboratories for Arboviruses, in agreement with the National Plan on human surveillance of vector-borne diseases. Both serological (ELISA IgM test and Plaque Reduction Neutralization Test-PRNT) and molecular assays (Real Time PCR tests, RT-PCR plus nested PCR and sequencing of positive samples) were performed.Results: DENV infection was the most frequently diagnosed (80 confirmed/probable cases), and all four genotypes were detected. However, an increase in imported CHIKV cases (41 confirmed/probable cases) was observed, along with the detection of the first ZIKV cases (4 confirmed cases), as a consequence of the recent spread of both CHIKV and ZIKV in the Americas.Conclusions: Main diagnostic issues highlighted in our study are sensitivity limitations of molecular tests, and the importance of PRNT to confirm serological results for differential diagnosis of Arboviruses. The continuous evaluation of diagnostic strategy, and the implementation of laboratories networks involved in surveillance activities is essential to ensure correct diagnosis, and to improve the preparedness for a rapid and proper identification of viral threats. [ABSTRACT FROM AUTHOR]

The pathophysiological hallmark of spotted fever group rickettsioses comprises vascular inflammation. Based on the emerging importance of the wingless (Wnt) pathways in inflammation and vascular biology, we hypothesized that Dickkopf-1 (DKK-1), as a major modulator of Wnt signaling, could be involved in the pathogenesis in rickettsial infections. Our major findings were: (i) While baseline concentration of DKK-1 in patients with R. conorii infection (n = 32) were not different from levels in controls (n = 24), DKK-1 rose significantly from presentation to first follow-up sample (median 7 days after baseline). (ii) In vitro experiments in human umbilical vein endothelial cells (HUVECs) showed that while heatinactivated R. conorii enhanced the release of interleukin-6 (IL-6) and IL-8, it down-regulated the release of endothelialderived DKK-1 in a time- and dose-dependent manner. (iii) Silencing of DKK-1 attenuated the release of IL-6, IL-8 and growth-related oncogene (GRO)α in R. conorii-exposed HUVECs, suggesting inflammatory effects of DKK-1. (iv) Silencing of DKK-1 attenuated the expression of tissue factor and enhanced the expression of thrombomodulin in R. conorii-exposed HUVECs suggesting pro-thrombotic effects of DKK-1. The capacity of R. conorii to down-regulate endothelial-derived DKK-1 and the ability of silencing DKK-1 to attenuate R. conorii-induced inflammation in endothelial cells could potentially reflect a novel mechanism by which R. conorii escapes the immune response at the site of infection. [ABSTRACT FROM AUTHOR]

To evaluate seroprevalence of B. henselae infection both in Sicilian children and healthy blood donors. Furthermore, circulation of Bartonella in the natural reservoir was also studied. Two hundred forty-three children, living in Sicily (Palermo), affected by various diseases, without clinical features suggesting B. henselae infection, together with 122 healthy blood donors were serologically investigated for IgG and IgM antibodies by indirect fluorescent antibody test (IFAT). One hundred twenty stray and 62 pet cats were also analyzed only for IgG. Among children 25.1% had IgG antibodies to B. henselae; 18.5% showed a titer 1:64, 2.4% 1:128, 2.4% 1:256, 0.8% 1:512, 0.4% 1:1024, and 0.4% 1:5120. Among healthy blood donors 11.4% had IgG class antibodies to B. henselae; 9.8% showed a titer 1:64 and 1.6% 1:128. All the human serum samples did not show positive results for B. henselae IgM class antibodies. Stray cats (68.3%) and pet cats (35.4%) also had IgG class antibodies to B. henselae. We demonstrated high frequency of serologic evidence of past B. henselae infection, in young Italian children, affected by various diseases, apparently free of any clinical features suggesting B. henselae infection. This observation is supported by high circulation of Bartonella in cats. [ABSTRACT FROM PUBLISHER]

The potential involvement of apoptosis in the pathogenesis of visceral leishmaniasis (VL) was examined by studying spontaneous andLeishmaniaantigen (LAg)-induced apoptosis using cryopreserved peripheral blood mononuclear cells (PBMC) of Sicilian patients with VL. Results indicate that monocytes and T lymphocytes from acute VL patients show a significantly higher level of apoptosis compared with that observed in healed subjects. The percentage of apoptotic cells was higher in monocytes than in T lymphocytes. T cells involved in programmed cell death (PCD) were mainly of the CD4+ phenotype. In particular, the T helper 1-type (Th1) subset, as evaluated by chemokine receptor-5 (CCR5) expression, is involved in this process. Cell death in Th1-type uses a CD95-mediated mechanism. Furthermore, Th1-type CCR5+ cells are prone to cell suicide in an autocrine or paracrine way, as attested by enhanced expression of CD95L in acute VL patients. The reduction in Th1-type cells by apoptosis was confirmed by the decrease in interferon-γ secretion. In conclusion, apoptosis of monocytes, CD4+ and CD4+ CCR5+ T cells could be involved in the failure of cell mediated immunity that is responsible for severe immune-depression in VL. [ABSTRACT FROM AUTHOR]