Showing papers by "Giovanni Rezza published in 2006"

Molecular epidemiology: HIV-1 and HCV sequences from Libyan outbreak

Abstract: In 1998, outbreaks of human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV) infection were reported in children attending Al-Fateh Hospital in Benghazi, Libya. Here we use molecular phylogenetic techniques to analyse new virus sequences from these outbreaks. We find that the HIV-1 and HCV strains were already circulating and prevalent in this hospital and its environs before the arrival in March 1998 of the foreign medical staff (five Bulgarian nurses and a Palestinian doctor) who stand accused of transmitting the HIV strain to the children.

Associations of classic Kaposi sarcoma with common variants in genes that modulate host immunity.

Abstract: Classic Kaposi sarcoma (CKS) is an inflammatory-mediated neoplasm primarily caused by Kaposi sarcoma–associated herpesvirus (KSHV). Kaposi sarcoma lesions are characterized, in part, by the presence of proinflammatory cytokines and growth factors thought to regulate KSHV replication and CKS pathogenesis. Using genomic DNA extracted from 133 CKS cases and 172 KSHV-latent nuclear antigen-positive, population-based controls in Italy without HIV infection, we examined the risk of CKS associated with 28 common genetic variants in 14 immune-modulating genes. Haplotypes were estimated for IL1A, IL1B, IL4, IL8, IL8RB, IL10, IL12A, IL13 , and TNF . Compared with controls, CKS risk was decreased with 1235T/−1010G–containing diplotypes of IL8RB (odds ratio, 0.49; 95% confidence interval, 0.30-0.78; P = 0.003), whereas risk was increased with diplotypes of IL13 containing the promoter region variant 98A (rs20541, alias +130; odds ratio, 1.88; 95% confidence interval, 1.15-3.08; P = 0.01) when considered in multivariate analysis. Risk estimates did not substantially vary by age, sex, incident disease, or disease burden. Our data provide preliminary evidence for variants in immune-modulating genes that could influence the risk of CKS. Among KSHV-seropositive Italians, CKS risk was associated with diplotypes of IL8RB and IL13 , supporting laboratory evidence of immune-mediated pathogenesis. (Cancer Epidemiol Biomarkers Prev 2006;15(5):926–34)

Bacterial isolates from severe infections and their antibiotic susceptibility patterns in Italy: a nationwide study in the hospital setting.

Abstract: The most frequent agents of severe bacterial infections and their antibiotic susceptibility patterns were determined in patients admitted to 45 Italian hospitals over the years 2002-2003. The most common diagnoses were: sepsis (33.8%), pneumonia (9.4%), intravascular catheter-associated infections (9.3%) and ventilator-associated pneumonia (8.1%). Overall, 5115 bacterial isolates were identified from 4228 patients. Three bacterial species, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli, accounted for more than 50% of the isolates. Other prevalent bacterial isolates were Staphylococcus epidermidis and Enterococcus faecalis, while Acinetobacter baumanii ranked third among all Intensive Care Unit (ICU) isolates. 7% of S. aureus had intermediate resistance to vancomycin. Although E. faecalis displayed no vancomycin resistance, 34% of vancomycin-resistant isolates were found among Enterococcus faecium, one of the highest rates found to date, emphasizing the difference between these two enterococcal species. All the Gram-positive pathogens were susceptible to linezolid, with the exception of approximately 2% of the enterococcal isolates that were intermediate with a minimum inhibitory concentration (MIC)=4 microg/ml. Almost 10% of Escherichia coli, 14% of Klebsiella pneumoniae, 22% of Serratia marcescens and 50% of Enterobacter cloacae were non-susceptible to cefotaxime. Amikacin was the most active antibiotic against P. aeruginosa that showed lack of susceptibility to ceftazidime, gentamicin, piperacillin and ciprofloxacin ranging from 20 to 35%. Finally, Acinetobacter baumanii showed a high level of resistance to all the antibiotics tested including imipenem (58%). The results obtained in this study, the first of its kind in Italy, offer indications for guiding empirical therapy and implementing specific interventions to fight antibiotic-resistant bacterial infections and their transmission in the hospital setting in Italy.

H5N1 influenza virus evolution: a comparison of different epidemics in birds and humans (1997-2004).

Abstract: The selection pressure acting along the entire genome sequence of H5N1 avian influenza viruses isolated from several bird species and humans infected in the 1997 and 2004 outbreaks, and on the HA1 genes from H5N1 viruses isolated during the entire study period, in eastern Asia was evaluated. According to maximum-likelihood analysis, viral genes appeared to be, in both epidemics, under strong purifying selection, with only the PB2, HA and NS1 genes under positive selection. Specific codons under positive selection were detected by using codon-based substitution models. Positive-selection analysis performed on single-codon sites might be helpful in clarifying the driving force of avian and human influenza virus evolution and in selecting specific targets for vaccines and antiviral drugs.

An outbreak of influenza in a residential drug-rehabilitation community.

Abstract: Influenza outbreaks can be difficult to control in confined settings where high-risk individuals are concentrated. Following the occurrence of a large number of cases of influenza-like illness in a rehabilitation community for drug users, between February and March 2004, surveillance activities were implemented. Attack rates of influenza-like illness were calculated, and risk factors for the development of disease and complications were evaluated through the use of relative risks (RR) with 95% confidence intervals (CI). Nasal-pharyngeal samples were collected for virological studies. Of 1,310 persons who were living in the community, 209 were diagnosed with influenza-like illness: the attack rate (15.9% overall) was higher for HIV-infected persons (RR: 1.77, 95% CI: 1.32-2.37), older individuals, and dormitory residents. HIV-infected participants were also more likely to develop complications compared with HIV-uninfected persons diagnosed with influenza-like illness (RR: 5.13, 95% CI: 2.52-10.20). The outbreak was attributable to Christchurch-like influenza A strains. Vaccination was ineffective because of the mismatch between wild and vaccine strains.

Respiratory viruses and influenza-like illness: a survey in the area of Rome, winter 2004-2005.

Abstract: Limited information is available on the viral aetiology of influenza-like illness (ILI) in Southern European countries. Hereby we report the main findings of a survey conducted in the area of Rome during the 2004-2005 winter season.ILI cases were defined as individuals with fever >37.5 degrees C and at least one constitutional symptom and one respiratory symptom, recruited during the survey period. Influenza and other respiratory viruses were identified using polymerase chain reaction (PCR) on throat swabs. Basic individual information was collected through a standard form. Of 173 ILI cases enrolled, 74 tested positive for one virus, and two tested positive for two viruses. Overall, 33.5% of the cases were positive for influenza viruses, 5.2% for adenoviruses, 3.5% for parainfluenza viruses, 1.7% for coronaviruses, and 1.2% for the respiratory syncitial virus. The proportion of influenza virus detection was higher in the 'high influenza activity' period. The distribution of viral agents varied across age groups, influenza viruses being more likely to be detected in younger patients. Viral pathogens were identified in less than 50% of ILI cases occurred during a high activity influenza season. The detection of other than influenza viruses was sporadic, without evidence of large outbreaks due to specific agents.

Evidence for lack of cervical cancer screening among HIV-positive women in Italy.

Abstract: Human immunodeficiency virus (HIV)-positive women are at greatly increased risk for infection with human papillomavirus (HPV), the main cause of cervical cancer, compared with HIV-negative women (Strickler et al., 2005). They also have an increased probability of harbouring multiple HPV types and developing persistent HPV infection (Strickler et al., 2005) and cervical cancer (Dal Maso et al., 2003). Invasive cervical cancer was included among AIDS-defining illnesses in 1993 (Ancelle-Park, 1993). Whereas highly active antiretroviral therapy (HAART) has been very effective in reducing the incidence of Kaposi sarcoma and non-Hodgkin lymphoma among HIV-positive individuals (Clifford et al., 2005), its effect on HPV infection and HPV-related cancer is modest at best (Heard et al., 2004; Clifford et al., 2005).

Prevalence of antibodies against A and B influenza viruses in South-Western Papua New Guinea.

Abstract: Influenza viruses remain a major cause of respiratory disease in both developed and developing countries. Nevertheless, there is little information on the prevalence of this respiratory infection in many developing countries, such as Papua New Guinea, since most of the available data originate from studies carried out in industrialized countries. In the present study, a serosurvey among residents of 47 remote villages of Papua New Guinea was conducted to evaluate the intensity of exposure to human influenza A and B viruses. The data obtained confirm the co-circulation of these antigenic variants, reported having circulated in the Southern Hemisphere. Variations in seroprevalence of influenza A and B virus infection were found within the study area. J. Med. Virol. 78:820–824, 2006. © 2006 Wiley-Liss, Inc.

The principle of precaution-based prevention: a Popperian paradox?

Abstract: One may suppose that prevention, as well as treatment, should be based on scientific evidence. However, no decision regarding public-health policy depends solely on epidemiological or toxicological data. To this regard, Rothman affirms that ‘the optimists among us hope that the fruit of scientific labour will enlighten the political process that ultimately decides the policy, but let us not be deluded into thinking that policies are or should be chosen solely by the evaluation of data’.1 In fact, public health is not necessarily a science but a form of ‘social activism’,2 and decision makers may be unaware of, or even choose to ignore, scientific results. Although it would be desirable to implement an intervention only when there is strong evidence of a causal relationship between exposure to a given factor and a disease event, other factors influence public-health decision-making (e.g., social, religious, cultural, and political factors, such as rights and liberties and economic considerations), which …

L'epidemia da HIV/AIDS in Provincia di Sassari nell'era della terapia antiretrovirale combinata

Abstract: Combined antiretroviral therapy has reduced both AIDS mortality and morbidity. An unknown proportion of patients is identified early and starts therapy before developing AIDS, thus escaping epidemiological surveillance. For this reason it is important to monitor the trend of new diagnoses of HIV infection. From the comparison of patients living in the Province of Sassari with new diagnoses of HIV infection or AIDS in the period 1997-2003 some differences emerge. Males are the most affected, but the difference tends to decrease among new HIV cases. Sexual contact is the most common route of transmission among new HIV diagnoses, whereas the parenteral route prevails among AIDS cases. An increase in the percentage of foreigners has been found only among new HIV cases. The difference found between new AIDS and HIV cases emphasises the importance to implement HIV infection based surveillance systems, in order to better guide informative campaigns and other interventions.