The impact of the Catholic Jubilee in 2000 on infectious diseases. A case-control study of giardiasis, Rome, Italy 2000-2001.

Mass gatherings are believed to increase the transmission of infectious diseases although surveillance systems have shown a low impact. The Catholic Jubilee was held in Rome, Italy in 2000. We conducted a case-control study to analyse the risk factors of giardiasis among residents. All diseases reported to the laboratory surveillance system from January 2000 to May 2001 were compared with hospital controls concurrently selected in the same season as cases and frequency-matched for age and birth country. Fifty-two cases (44.1%) and 72 controls were enrolled. In the multivariable analysis factors associated with giardiasis among adults were: travelling abroad (OR 24.2, P>0.01), exposure to surface water (OR 4.80, P=0.05), high educational level (OR 3.8, P=0.03). Having a maid from a high-prevalence country was independently associated (OR 2.3) although not statistically significant. This is the only exposure that changed during the Jubilee.

Effects of vaccination against bluetongue on milk production and quality in cattle vaccinated with live-attenuated monovalent type 2 vaccine.

The first epidemic of bluetongue (BT) to affect the three regions of Sardinia, Sicily and Calabria (Italy) in 2000 induced high economic losses caused by the disease itself and by the cessation of ruminant movements both within, and out of, the infected areas. In order to reduce virus circulation, and to create a resistant livestock population, the Italian Ministry of Health ruled, in May 2001, that all sheep, cattle, goats and water buffalo, in infected and in neighbouring regions, be vaccinated. The live-attenuated BTV-2 monovalent vaccine produced by Onderstepoort Biological Products in South Africa was to be used. Accordingly, in 2002, 98.6% of the sheep and goats, and 88.1% of the cattle, on Sardinia were vaccinated. Included was the vaccination of >70% of the cattle in the province of Oristano where >18,000 dairy cows in >220 herds are concentrated in the municipality of Arborea (Oristano) and which account for 65-70% of the milk produced in Sardinia. Using data collected at the centralised dairy co-operative since 1999 the quantity and quality of milk produced before vaccination against bluetongue was compared to that produced after vaccination. The following variables were analysed: average milk production/cow/month, monthly average fat content (%), monthly average protein content (%), average monthly somatic cell count and average monthly platelet count. The findings indicate that vaccination against BTV-2 in Sardinian dairy cattle did not impact negatively upon milk quantity nor milk quality.

Monovalent modified-live vaccine against bluetongue virus serotype 2: immunity studies in cows.

A challenge study was conducted to determine the efficacy of vaccination against bluetongue (BT) virus (BTV) serotype 2 in protecting cattle against infection. A group of 30 cows, vaccinated seven months previously with monovalent BTV-2 modified-live vaccine produced by Onderstepoort Biological Products in South Africa, were challenged subcutaneously with 2x 10(5.8)TCID50/ml of BTV-2 field isolate. All cattle originated from the same population in the Sardinian province of Oristano. Eight unvaccinated calves from a BTV-free herd also participated in this study; four were inoculated with BTV-2 and used as positive controls whilst the remaining four were used as negative controls to confirm that no BTV was circulating locally. Blood samples were taken from all animals three times a week for two months. Serum samples were tested for antibody against BTV using the competitive enzyme-linked immunosorbent assay (c-ELISA) and the virus neutralisation (VN) test. Virus isolation was attempted on the blood samples by intravenous egg inoculation followed by two blind passages in Vero cells. Virus titres following challenge were determined also. Of the 30 cows vaccinated, 29 were positive in the c-ELISA and demonstrated neutralising antibodies. At the time of challenge, 11 cows had no virus neutralising antibody while the remainder had low titres ranging from 1:10 (11 cows) to 1:20 (6 cows); two cows showed titres of 1:40 and 1:80, respectively. None of the cows showed signs of disease after challenge and no BTV was isolated from the blood of the 29 cows that had developed antibodies after vaccination. Commencing on day 9 post challenge, BTV-2 was isolated from the blood of the single cow that had not seroconverted following vaccination and from the blood of the unvaccinated controls. Viraemia lasted until day 21 post challenge. Neither BTV nor antibody was detected in the blood samples taken from the negative control group. These observations indicate that the monovalent BTV-2 modified-live vaccine protects most animals when challenged with field virus seven months post vaccination.

Neutralising antibody response in cattle after vaccination with monovalent modified-live vaccine against bluetongue virus serotype 2.

The antibody response following bluetongue (BT) vaccination under both field and experimental conditions, and the duration of colostral antibodies in calves born from vaccinated dams, were evaluated. To this end, 1 005 animals of various breeds and ages were selected at random from 10 herds in the Sardinian province of Oristano. During the first year of the vaccination campaign, the animals selected were vaccinated against BT virus (BTV) serotype 2 between July and August 2002. Blood samples were taken from all animals monthly for three months after vaccination and tested for the presence of BT antibodies using the competitive enzyme-linked immunosorbent assay (c-ELISA) and the virus neutralisation (VN) test. Serological results from field vaccinated animals were compared with those obtained following the vaccination of five animals under experimental conditions. Out of 1,005 animals, 994 (98.1%) developed BT antibody following vaccination whereas antibody was detected in all cows vaccinated under experimental conditions. Both groups showed the highest median titres of 1:160 after two months. To assess the duration of colostral antibodies in calves born from vaccinated dams, the sera of 47 calves were screened using the c-ELISA and VN test. Calves were divided into three age groups: Group A included 22 calves aged 1 to 25 days, Group B 13 calves aged 26 to 39 days and Group C 12 calves aged 40 to 60 days. Antibody was detected in calves in Groups A and B (68.2% and 46.1%, respectively) whereas the calves in Group C were serologically negative.

Anaerobic bacteria in postsurgical infections: isolation rate and antimicrobial susceptibility.

Three hundred clinical samples, obtained from post-surgical infections, were evaluated. 37% of samples were positive for anaerobes, 99 samples (33%) for aerobes and anaerobes in mixed culture, and 13 (4%) only for anaerobes. One hundred forty-nine anaerobic strains were isolated: Bacteroides and Clostridia occurred most frequently (34% and 23% respectively). Antimicrobial susceptibility of the isolates was tested by means of a commercial broth microdilution method. In addition, the standardized agar dilution method was performed to evaluate the susceptibility to 8 antibiotics of the 51 Bacteroides strains.

Anaerobic bacteria and bacterial infections: perspectives on treatment and resistance in Italy.

Results of laboratory tests of 2,000 samples obtained from 1984 to 1987 from patients with suspected anaerobic infections and the clinical experience of these patients are reported. Of these samples, 395 were positive for anaerobes; 36.5% of these 395 samples contained single organisms, and 63.5% contained a mixture of anaerobes and aerobes. Abdominal infections were the infections most frequently caused by anaerobes. The Bacteroides fragilis group and strains of Peptostreptococcus were the microorganisms most frequently isolated. In addition, 300 anaerobes isolated from clinical samples at three Italian hospitals were tested for susceptibility to 10 antibiotics (aztreonam, cefotaxime, cefoxitin, ceftazidime, ceftriaxone, clindamycin, imipenem, metronidazole, penicillin, and piperacillin). Imipenem and metronidazole proved to be the most active agents, with low and similar values for the 50% and 90% minimal inhibitory concentrations (MICs). No microorganism showed resistance to these agents. After imipenem and metronidazole, clindamycin was the most effective agent tested. All other antibiotics tested showed elevated MICs against Bacteroides species and Clostridium difficile. In Italy, cefoxitin still maintains satisfactory activity against the majority of anaerobes tested.

HNK-1 peripheral blood lymphocytes in HIV infected patients.

Peripheral blood cells with the HNK-1 phenotype were studied in HIV infected patients of which 28 with Asymptomatic Infection (AI), 64 with Persistent Generalized Lymphoadenopathy (PGL), 9 with AIDS Related Complex (ARC), and 12 with AIDS. Eight normal subjects served as controls. Two-color immunofluorescence by flow cytometry analysis showed in all of them a significant increase of the mean percentage of HNK+T3- lymphocytes (greater than 20%) as compared to controls (6%). Only in AI the mean absolute count was significantly higher (776/cmm) than control's one (152/cmm). Percentages and absolute counts of HNK+T3- lymphocytes were similar to normal ones. In AI and PGL HNK+T3+ cells correlated directly with T8 lymphocytes and inversely with T4 cells and T4/T8 ratio. These results indirectly suggests that HNK+T3+ cells represent a subset of suppressor/cytotoxic lymphocytes. The results in ARC and AIDS were somewhat equivocal and deserve further study in larger samples. No correlation was found between HNK+T3+ and HNK+T3- cells. The expansion of HNK+T3+ cells was parallel to that one of T8 lymphocytes expressing CD8 antigen at high surface density which were previously reported as having cytotoxic activity. Follow-up studies of the HNK cell peripheral pattern will clarify if it can be regarded as an early predictor of clinical outcome.

Antibiotic treatment of anaerobic infections.

Many bacterial infections, for example those in chest and abdomen, intracranial infections and infections in the female genital tract have anaerobic or mixed aerobic/anaerobic aetiology. Recent data indicate that anaerobes, alone or together with aerobes, are found in 15% to 30% of all positive bacteriological cultures. In 1988 at our laboratory, 284 (75%) of 379 positive cultures yielded aerobes only, 23 (6%) anaerobes only and 72 (19%) mixed aerobes and anaerobes. The initial choice of antibiotics in infections known or suspected to involve anaerobes should be based on the site of the infection, the anticipated aetiology and the severity of the infection. The place in therapy of antibiotics active against anaerobes is discussed.

Evidence for cross-infection in an outbreak of Clostridium difficile-associated diarrhoea in a surgical unit.

Environmental studies were performed in a hospital outbreak of Clostridium difficile-associated diarrhoea. Transmission was associated with the sluice room and the storage room where medical equipment was found to be contaminated with C.difficile. Typing of isolates by antibiotic-susceptibility patterns and profiles of EDTA-extracted proteins showed the presence of an "epidemic" strain common to the majority of patients and environmental sites. Control of the outbreak was achieved by improvement of environmental hygiene and use of disposable equipment.

Isolation of Clostridium difficile from human jejunum: identification of a reservoir for disease?

The possibility that the small intestine may represent a reservoir for Clostridium difficile was studied, using segments of human jejunum collected at necropsy. Our results (three of 100 specimens positive for C difficile culture) support the hypothesis that C difficile can be found in human jejunum and that it adheres to the normal mucosa as a resident bacterium. These findings suggest that gastrointestinal disease caused by C difficile has an endogenous origin.

[HLA and hypo-responsivity to anti-HBV vaccination (genetic study of non-responder subjects to anti-hepatitis B viral vaccine)]. / HLA e iporesponsività alla vaccinazione anti-HBV (studio genetico di soggetti non-responders al vaccino anti-epatite virale B).

The control of the immunization due to hepatitis B vaccines (HB-VAX and HEVAC B) showed that a low percentage of healthy adults vaccinated develop a non protective title of HBsAb or do not produce antibodies. The correlation between immunity and HLA has already been demonstrated: HLA is at the base of individual immunological response; this correlation directed our genetic study of low-responders or non-responders patients to anti-HBV vaccine. In our study 11 out of 97 subjects vaccinated (11.34%) with HB VAX or HEVAC B resulted hyporesponsive and underwent complete HLA typing to verify the relation between immune deficiency response and genetic system. There was an increase in phenotype HLA-DR7 incidence, with respect to a non-selective population and a decrease of HLA-DR1, as it has already been mentioned in the literature, the variations were not statistically significant taking into account the exiguity of the samples considered.