Mauro Bendinelli

Human Metapneumovirus Associated with Respiratory Tract Infections in a 3-Year Study of Nasal Swabs from Infants in Italy

ABSTRACT The newly described human metapneumovirus (hMPV) is reported here to be more commonly associated with lower respiratory tract disease. The present study examined nasal swab specimens from 90 infants with acute respiratory tract infections in Pisa, Italy, over a period of three respiratory virus seasons. The incidence of infection varied in each of the 3 years, with the rates of positivity for hMPV being 7% in 2001 but 37 and 43% in 2000 and 2002, respectively. hMPV was noted to occur seasonally in a pattern typical of the frequency of occurrence of respiratory syncytial virus. More than one-half (14 of 23) of the infants infected with hMPV had bronchopneumonia. One-third (9 of 23) of the hMPV-infected patients were also infected with another respiratory virus, a relationship that has not previously been reported. Mixed infections did not account for a higher percentage of cases of bronchopneumonia than hMPV infection alone did. Furthermore, 7 of 17 infants whose plasma was also tested for hMPV RNA were demonstrated to have virus in both nasal swab and blood specimens. The study indicates that hMPV is seen as commonly as other respiratory viruses, may be associated with severe respiratory disease in infants, can establish mixed infections with other respiratory viruses, and has a seasonal occurrence.

Molecular Properties, Biology, and Clinical Implications of TT Virus, a Recently Identified Widespread Infectious Agent of Humans

SUMMARY TT virus (TTV) was first described in 1997 by representational difference analysis of sera from non-A to non-G posttransfusion hepatitis patients and hence intensively investigated as a possible addition to the list of hepatitis-inducing viruses. The TTV genome is a covalently closed single-stranded DNA of approximately 3.8 kb with a number of characteristics typical of animal circoviruses, especially the chicken anemia virus. TTV is genetically highly heterogeneous, which has led investigators to group isolates into numerous genotypes and subtypes and has limited the sensitivity of many PCR assays used for virus detection. The most remarkable feature of TTV is the extraordinarily high prevalence of chronic viremia in apparently healthy people, up to nearly 100% in some countries. The original hypothesis that it might be an important cause of cryptogenic hepatitis has not been borne out, although the possibility that it may produce liver damage under specific circumstances has not been excluded. The virus has not yet been etiologically linked to any other human disease. Thus, TTV should be considered an orphan virus.

TT virus in the nasal secretions of children with acute respiratory diseases: relations to viremia and disease severity.

ABSTRACT The natural history and pathogenic potential of the recently identified TT virus (TTV) are currently a matter of intensive investigation. In an attempt to shed some light on these issues, nasal and blood specimens of 1- to 24-month-old children hospitalized with a clinical diagnosis of acute respiratory disease (ARD) were examined for the presence, load, and genetic characteristics of TTV. The results have indicated that at least in young children, the respiratory tract not only represents a route by which abundant TTV can be shed into the environment but also may be a site of primary infection and continual replication. Although we found no compelling evidence that TTV was the direct cause of ARD in some of the children studied, the average loads of TTV were considerably higher in patients with bronchopneumonia (BP) than in those with milder ARD, raising interesting questions about the pathophysiological significance of TTV at this site. Furthermore, group 4 TTV was detected almost exclusively in children with BP.

Pseudomonas aeruginosa as an Opportunistic Pathogen

Provides balanced coverage of epidemiology, pathogenesis, clinical features, and control measures in 19 chapters contributed by authorities on specific aspects of P. aeruginosa research. The volume should prove useful to physicians and surgeons who have in their care patients infested, or at risk of

Fungal Infections and Immune Responses

Introduction to Fungal Infections and Immune Responses J.W. Murphy. Superficial Fungal Infections P.G. Sohnle. Dermatophytosis P.G. Sohnle. Introduction to Candida-Systemic Candidiasis J.E. Domer, R.I. Lehrer. Chronic Mucocutaneous Candidiasis S.G. Filler, J.E. Edwards. Sporotrichosis E.N. Scott, H.G. Muchmore. Blastomycosis A.M. Sugar. Coccidioidomycosis R.A. Cox. Histoplasmosis B. Wu Hsieh, D.H. Howard. Paracoccidioidomycosis A. RestrepoMoreno. Cryptococcosis T.R. Kozel. Chromoblastomycosis G.E. Hollick. Mycotic Mycetoma M.M. El-Zaatari, M.R. McGinnis. Pseudallescheriasis C.R. Cooper, Jr., I.F. Salkin. Aspergillosis J.C. Rhodes. Phaeohyphomycosis M.M. El-Zaatari, M.R. McGinnis. Fungal Allergy V.P. Kurup, J.N. Fink. Fungal Infections in the Immunocompromised Host H. Chmel. Immunochemistry of Fungal Antigens E. Reiss. 6 additional articles. Index.

Differences in hepatitis C virus quasispecies composition between liver, peripheral blood mononuclear cells and plasma

Hepatitis C virus (HCV) exists in vivo as a highly variable mixture of closely related genomes (quasispecies), but the pathogenetic significance of such heterogeneity is still largely unknown. To investigate this issue, we compared the composition of HCV quasispecies found in the liver, peripheral blood mononuclear cells (PBMC) and plasma of ten patients by single-strand conformation polymorphism analysis of the E2/NS1 region and sequencing of the variants detected. We found considerable quasispecies differences between the liver and PBMC in all the patients, involving variant numbers, relative quantities and relative electrophoretic mobilities, but no apparent tissue-specific trend. Genome variants present in the liver and/or PBMC were not detected in the corresponding plasma samples, while certain HCV variants were present only in plasma. No dominant amino acids or amino acid pattern characteristic of variants present solely in the PBMC were detected in the E2/NS1 region sequenced.

Prevalence of feline immunodeficiency virus and other retroviral infections in sick cats in Italy

Two hundred and seventy-seven sick pet cats living in Italy were tested for antibodies to feline immunodeficiency virus (FIV) and for feline leukemia virus (FeLV) antigen. Overall, 24% of the cats resulted positive for anti-FIV antibody and 18% for FeLV antigen. FIV was isolated from the peripheral mononuclear blood cells of ten out of 15 seropositive cats examined and from one out of eight saliva samples. No FIV isolations were obtained from six serum samples cultured. Feline syncytium forming virus (FeSFV) could be isolated from blood and/or saliva in ten out of 11 FIV seropositive cats examined, in six out of nine FeLV antigen positive cats, in two cats found positive for both infection markers, and in three out of 11 cats negative for both markers. Thus, the probability of isolating FeSFV was enhanced by infection with other exogenous retroviruses.

High Prevalence of TT Virus Viremia in Italian Patients, Regardless of Age, Clinical Diagnosis, and Previous Interferon Treatment

The pathogenic potential of the newly discovered TT virus (TTV) is currently a matter of conjecture. Its presence was investigated in the serum of 660 patients, by polymerase chain reaction. TTV was detected in 50% of 221 patients with unselected pathologies, and no significant differences related to age, sex, or organ disease were noted. TTV was present at a significantly higher rate in hemophiliacs (73%) and at lower rates in patients with cirrhosis (30%) and rheumatoid arthritis (28%). Patients with other liver diseases, systemic lupus erythematosus, or psoriasis or receiving hemodialysis had rates of infection similar to those in unselected patients. TTV-positive patients treated with interferon-alpha for underlying type C hepatitis showed no appreciable changes of TTV viremia levels. Type 1b was by far the most frequent viral genotype (92%), followed by types 2c (5%) and 1a (3%).

Detection and quasispecies analysis of hepatitis C virus in the cerebrospinal fluid of infected patients.

Hepatitis C virus (HCV) is a leading cause of liver damage and has also been implicated in extrahepatic pathologies. We examined for HCV RNA paired CSF and plasma samples from 12 viremia positive patients using PCR. The CSF from 5/5 HIV-infected patients and 5/7 HIV-negative patients were HCV RNA positive. Branched DNA analysis showed that HCV loads in CSF were much lower than in plasma. Several HCV-positive CSF showed no evidence of blood contamination, impaired blood-brain barrier, or intrathecal IgG production. Comparison of HCV quasispecies in three sets of samples suggested that the virus in CSF was of plasma origin.

Retrovirus-induced acquired immunodeficiencies.

Publisher Summary This chapter discusses the Retrovirus (RV)-induced acquired immunodeficiency. It deals primarily with the former type of mechanisms, but emphasizes that distinguishing between tumors-unrelated and tumor-dependent immunodepressive events may be exceedingly difficult. RV can adversely affect the functioning of the immune system. In a limited number of infections of lower animals, a multiplicity of phenomena pertaining to the whole organism and to isolated immunocompetent cells has been described. Infected hosts have been shown to mount reduced responses against a variety of immunogens and to present a subnormal resistance to superinfecting agents. Functional tests have established that all classes of immunocytes exhibit potentially important alterations in their effectors, inducer, or immunoregulatory activities, and several pieces of evidence have suggested the centrality of macrophage impairment. Attempts to clarify the underlying mechanisms have indicated that many factors may contribute, but the direct interaction of the infecting virus with immunocompetent cells is of great importance. Even though it seems likely that active infection is a prerequisite for such cells to become grossly or permanently malfunctioning, the mere physical contact with the virion or with virion components has been shown to perturb both lymphocytes and macrophages.