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Food-borne infections are the most serious food safety problem in the world. In fact, they are responsible of millions of illnesses and thousand of deaths. Non-typhoid Salmonella infection is frequent world-wide and, although mild and self-limiting illness in normal subjects, it may cause a severe disease in patients with an immune-deficiency. Changes in the agents and in the vehicles of transmission and a higher number of patients with immune-depression have determined a world-spread of non-typhoid Salmonella infection in the last decades. The increased frequency of international travels and food commerce have been associated with outbreaks of unusual serotype of Salmonella. Moreover, drug-resistant Salmonella are emerged recently, as Ampicillin and Doxiciclin-resistant S. enteritidis or DT-104 multidrug-resistant S. typhimurium. The outbreak of Salmonella disease is also linked to diffusion of HIV infection and of other immunodeficiencies. The lack of controls in food industry, the frequent contamination of mass-distributed food products and the decreased opportunities to transmit for instruction on food safety, both in school and inside the family, are the causes of large-scale outbreaks

To evaluate the interference between HBV, HCV and HDV and the clinical impact of coinfection as compared with single HBV or HCV infection, we unrolled 618 HBsAg and/or anti-HCV positive subjects (337 with liver biopsy and 281 without liver biopsy) at their first observation at one of the seven Italian Liver Units from 1993 to 1997 (Padova, Rome, Sassari, Naples, Bari, Messina, Palermo). Serum HBV-DNA by dot-blot was found more frequently in patients with HBV infection alone (52% of 133 cases) than in those with HBV-HCV coinfection (28% of 64 cases, p<0.005) or in those with HBV-HDV-HCV coinfection (12% of 25 cases, p<0.0005) or with HBV-HDV coinfection (13% of 8 cases, p<0.05). We observed a higher prevalence of HCV-RNA positive cases in the patients with HCV infection alone (91.2% of 114 cases) than in those with HBV-HCV coinfection (64.5% of 62 cases, p<0.0001) or with HBV-HDV-HCV infection (19% of 21 cases, p<0.0001). These observations suggest a reciprocal inhibition of HBV and HCV genome in multiple hepatitis viral infection. A severe liver disease was more frequently observed in patients with HBV-HCV coinfection (66%) than in those with a single HBV infection (43%, p<0.05) or HCV infection (46%, p<0.05). Anti-HCV positive/anti-HBc positive patients, lacking both HBsAg and anti-HBs, compared with the anti-HCV positive/anti HBc negative ones, more frequently showed severe clinical presentation and less frequently had a sustained response to a-IFN treatment.

The infective diarrhoea show a high morbility in infants of all countries and a high mortality in infants and children of developing countries. In developed countries there is a high frequency of "traveler's diarrhoea". The different pathogenesis of infectious diarrhoeas (intestinal invasion, intestinal adherence, citonecrotic or citotonic toxins) influences the clinical presentation (watery diarrhoea or diarrhoea with blood and mucos, presence or assence of fever). The key factor in the management of acute watery diarrhoea is the restoration of water and electrolyte balance; but frequently an antimicrobial treatment is needed.

Following the decrease in HAV endemic levels in the last decades, nowadays in Italy most people aged less than 30 years are susceptible to the infection. We have tested for serum anti HAV IgG 194 chronic hepatitis patients from Naples to evaluate the level of protection against HAV in a category of patients in whom an acute necrosis due to HAV might induce liver failure. The study shows that 90.7% of Neapolitan chronic hepatitis patients has serologic evidence of prior HAV infection. Specifically, 98.1% of the patients over 40 years of age, but only 54.6% of those under 40 tested positive for anti HAV IgG. 102 patients had cirrhosis and only one tested negative. The data suggest that HAV vaccination in susceptible chronic hepatitis patients should be judged by the physicians in care on the basis of the severity of disease, patient's age, real risk of exposure to the infection, and level of education.

To detect HIV antigens in circulating complement fixing immune complexes (ICs) we assessed an ELISA using wells of microtitre plates coated with F(ab)2 anti-C3b and monoclonal antibodies anti-HIV gp120 and anti-HIV p24. We tested 24 anti-HIV positive subjects (Group A), 10 anti-HIV negative subjects at risk of acquiring HIV infection (Group B), 20 normal controls (Group C) and 2 seroconversion panels. We found HIV antigens in ICs in all sera from seroconversion panels, in 25.5% of sera from subjects in Group A, in 28.6% of sera from subjects in Group B and in no serum from subjects in Group C. A subject in Group B acquired HIV infection during the observation. HIV antigens in ICs by our assay were detected 8 months before Anti-HIV and Ag by commercial ELISA.

To detect HlV proviral DNA in lymphocytes from subjects at risk of acquiring HIV infection, we assessed a Polymerase Chain Reaction Assay using the SK38 and SK39 primers for the amplification and the SK19 probe for the hybridization. The detection of amplified HIV-DNA was obtained by a new colorimetric method, the DNA enzyme immunoassay (DEIA). The PCR we performed allowed to detect HIV-pDNA in lymphocytes of 13 out of 64 subjects at risk of acquiring HIV infection. Seven of these 13 became anti-HIV positive during a follow up of 8 months.

The incidence rate of hepatocellular carcinoma (HCC) has been increasing over the last 20 years. HCC is a worldwide, but the incidence is very high in countries of South East Asia, China, sub-Saharan Africa and southern Europe. Liver cirrhosis is the most important risk factor for the development of HCC, through necrotic-proliferative and dysplastic activity. HBV is indicated as a carcinogen agent, while it is unknown the real role of HCV in hepatocarcinogenesis. The role played by aflatoxins, ethanol, hemochromatosis, familiarity and sex hormones is still undefined. The clinical presentation of HCC is similar to that of chronic hepatitis and cirrhosis indicating the need of a periodic screening (even 4-6 months) with alpha-fetoprotein determination and abdominal ultrasound scan. Hepatic resection, liver transplantation and percutaneous ethanol injection are the options more frequently chosen for treating patients with HCC.

To detect the presence of anti-HIV IgA in HIV infected subjects and in seronegative subjects at risk of infection, we assessed a Western Blot using nitrocellulose strips with HIV separated proteins. We tested at least 2 different serum samples from 9 anti-HIV positive subjects (Group A), 9 anti-HIV negative subjects at risk of infection (Group B) and 9 controls (Group C). One subject in Group B became anti-HIV positive during the observation. Anti-HIV IgA were detected in all patients of Group A, in 66.6% of patients of Group B and in no patient of Group C. The subject who seroconverted during the observation showed positivity for IgA anti-HIV in both serum samples, while anti-HIV IgG became detectable only on the second serum sample. A newborn from a seropositive mother showed maternal anti-HIV IgG on the first 2 out of 3 serum samples while showed anti-HIV IgA positivity on the third sample only. This child is still anti-HIV negative.

The diagnosis of HIV infection is generally lead using two different ELISAs to detect specific anti-HIV antibodies, the eventual reactivity must then be confirmed by a Western Blot The antibodies can be detected only 1-6 months after the infection; in fact in the earliest phases neither the antibodies, for their low titre, nor the specific antigens, for the antibodies could form immune complexes, can be detected by the achieved methods. Only the viral isolation can reveal the presence of the virus in this early phase, but the isolation must be conducted only in adequately safe laboratories (P3 laboratories). The only test able to replace the viral isolation is the Polymerase Chain Reaction (PCR). The PCR technique can be useful to reveal an HIV infection in its early phase and to monitor the infection progression and the efficacy of an antiretroviral treatment

Vertical transmission of hepatitis B virus (HBV) was studied in 21 mother-infant pairs. A transient HBs-antigenemia was observed in 60% of the 10 children born to HBsAg healthy carrier mothers and 91% of the 11 babies born to mothers with HBsAg-positive CAH. Among the 16 children showing HBs-antigenemia, 3 developed acute viral hepatitis two of whom showed progression to chronicity.

Eighty-eight drug addicts from the "BAN Center" in Torre Annunziata (Naples) and 88 normal subjects pair-matched for age and sex were tested for IgG to human immunodeficiency virus (HIV), herpes simplex virus (HSV) type 1 and 2 and cytomegalovirus (CMV). A high prevalence of subjects with antibodies to HSV-1 and CMV (80.7% and 65.9%) were recorded in the control group testifying to the high level of these infections in Campania. Prevalences were higher in drug addicts, and drug abuse was identified as a risk factor for the acquisition of CMV infection (odds ratio = 2.3). Moreover, drug addiction is also a risk factor for HSV-2 and HIV infection as demonstrated by the observation that drug abusers were anti-HSV-2 (9.1 vs. 1.1%, odds ratio = 6.16) or anti-HIV (11.4 vs. 0%, odds ratio = 23.6) positive more frequently than normal controls. Thus, drug addiction is a risk factor for the acquisition of HIV, HSV-2 and CMV infections. This is probably due to similar habits, frequent among drug addicts from our geographic area and uncommon in the normal population, such as tattooing, needle-sharing needlestick and unsafe sex. Some of these habits, such as unsafe sex and tattooing, seem to be, per se, risk factors for the acquisition of both HIV and CMV infections. The data also suggest that HIV infection was probably introduced in Campania more recently than in northern and central Italy where the prevalence of anti-HIV positive cases among drug addicts is definitely higher.