Biomedical subjects

F M Ruggeri

Publications and source records attributed to F M Ruggeri.

At least 19 recordsLinked to original sources

PubMed2007

The magnitude and distribution of infectious intestinal disease in Malta: a population-based study.

Routine sources of information on infectious intestinal disease (IID) capture a fraction of the actual disease burden. Population studies are required to measure the burden of illness. A retrospective age-stratified cross-sectional telephone study was carried out in Malta in order to estimate the magnitude and distribution of IID at population level. A random sample of 3504 persons was interviewed by a structured questionnaire between April 2004 and December 2005. The response rate was 99.7%. From the study, the observed standardized monthly prevalence was 3.18% (95% CI 0.7-5.74) with 0.421 (95% CI 0.092-0.771) episodes of IID per person per year. The monthly prevalence was higher in the <5 years age group and in females aged 31-44 years. The mean duration of illness was 6.8 days and a median duration of 3 days. A bimodal seasonal distribution was observed with peaks in June-July and October-November.

Adolescent↗

PubMed2006

Public health implications of a case of haemolytic-uraemic syndrome associated with a concomitant outbreak of mild gastroenteritis in a small rural community.

The concomitant occurrence of a case of haemolytic-uraemic syndrome (HUS) and 62 cases of mild gastroenteritis in schools of a small rural community in southern Italy induced the health authorities to suspect a foodborne outbreak of shiga-toxin-producing Escherichia coli (STEC) infection. The schools were closed and the catering service involved was investigated. However, STEC were not isolated from the HUS case or from the 56 cases of gastroenteritis examined, and the HUS case and the outbreak of gastroenteritis were probably just coincidental. A retrospective cohort study failed to show any correlation with consumption of school meals and suggested that the outbreak probably started outside the school setting and then spread within the schools by person-to-person transmission. All the cases examined were negative for common enteric pathogens and the responsible agent for the cases of gastroenteritis was not identified. The concern raised in the small community by the occurrence of a severe case of HUS and the lack of a rapid epidemiological assessment excluding the occurrence of a STEC outbreak, turned an epidemic episode of mild gastroenteritis into a public health emergency with relevant socioeconomic consequences. Prompt intervention in outbreaks following timely and effective risk communication are crucial for taking the most appropriate control measures and avoiding the spread of fear and panic in the community.

Child↗

PubMed2006

Detection of swine torque teno virus in Italian pig herds.

Anellovirus is a recently created, floating genus of viruses. Torque teno virus (TTV), the type species in the genus, was first discovered in a human patient with a post-transfusion hepatitis of unknown aetiology. Recently, TTV genetically related to but distinct from those discovered in humans have also been found in animals, including pigs. The aims of this study were to estimate the prevalence of swine TTV in Italian pig herds and some risk factors possibly associated with this infection. Serum samples from 179 healthy pigs from 10 farms located in north-central Italy were tested by polymerase chain reaction for the presence of swine TTV DNA. Viral DNA was found in the sera of 43 pigs (24.0%), coming from eight of the 10 farms examined. Prevalence was significantly higher in finishing herds (40.1%) than in farrow-to-finish herds (11.0%) and did not depend on the size of the herd. Within the finishing herds the prevalence was significantly higher in weaners (57.4%) than in fatteners (22.9%), but this difference was not observed in farrow-to-finish herds. No relationship was observed between the prevalence of swine TTV and the implementation of some general hygiene practices and biosecurity procedures within the herds.

Animal Husbandry↗

PubMed2005

Sequence analysis of the VP7 and VP4 genes identifies a novel VP7 gene allele of porcine rotaviruses, sharing a common evolutionary origin with human G2 rotaviruses.

During an epidemiological survey encompassing several porcine herds in Saragoza, Spain, the VP7 and VP4 of a rotavirus-positive sample, 34461-4, could not be predicted by using multiple sets of G- and P-type-specific primers. Sequence analysis of the VP7 gene revealed a low amino acid (aa) identity with those of well-established G serotypes, ranging between 58.33% and 88.88%, with the highest identity being to human G2 rotaviruses. Analysis of the VP4 gene revealed a P[23] VP4 specificity, as its VP8* aa sequence was 95.9% identical to that of the P14[23],G5 porcine strain A34, while analysis of the VP6 indicated a genogroup I, that is predictive of subgroup I specificity. Analysis of the 10th and 11th RNA segments revealed close identity to strains of porcine and human origin, respectively. The relatively low overall aa sequence conservation (<89% aa) to G2 human rotaviruses, the lack of N-glycosylation sites that are usually highly conserved in G2 rotaviruses, and the presence of several amino acid substitutions in the major antigenic hypervariable regions hampered an unambiguous classification of the porcine strain 34461-4 as G2 serotype on the basis of sequence analysis alone. The identification of a borderline, G2-like, VP7 gene allele in pigs, while reinforcing the hypotheses of a tight relationship in the evolution of human and animal rotaviruses, provides additional evidence for the wide genetic/antigenic diversity of group A rotaviruses.

Alleles↗

PubMed2001

Antigenic sites of poliovirus type 3 eliciting IgA monoclonal antibodies in orally immunized mice.

A panel of neutralizing IgA monoclonal antibodies was produced from mice orally inoculated with poliovirus type 3 Sabin and cholera toxin as adjuvant. Low levels of neutralizing antibodies were elicited in mice after several boosts, but only in the presence of cholera toxin. Characterization of IgA MAbs by neutralization-escape virus mutants showed that all but one neutralizing MAbs against type 3 poliovirus were directed to antigenic site N-AgIII, which was previously found by us to be the major target of mucosal immune response to Sabin 1 in the mouse. Our data indicate that residue 236 of VP3, not previously reported, is also involved in forming site N-AgIII in addition to formerly described VP3 (aa 58-59) and VP1 (aa 286-290) residues. Unlike poliovirus type 1 IgA MAbs, all IgA MAbs herein described neutralized the wild-type parental poliovirus.

Adjuvants, Immunologic↗

PubMed1999

Rotavirus infection among children with diarrhoea in Italy.

Despite the absence of a nationwide surveillance system for rotavirus infection, relevant information concerning the epidemiology of this pathogen in Italy can be obtained from hospital-based studies carried out since the early 1980s on patients with acute diarrhoea. A review of more than 50 papers and congress proceedings published in both international and national literature indicates that rotavirus is the most important cause of diarrhoea in Italy among young children requiring hospitalization, with a prevalence ranging from approximately 20% to 40% in different studies. Infection is predominant among children aged 6-24 months, although cases are also common in younger children and in children 2-3 y of age. Despite differences among studies in geographical area, years and age group under investigation, an increase in rotavirus cases is consistently reported in the winter months, with a peak in February through April. Although a few studies have been conducted in non-hospitalized patients, rotavirus infection is significantly less frequent among outpatients with enteritis than among inpatients. Most circulating rotavirus strains typed from 1981 to 1992 belong to serotype 1 and, to a lesser extent, 4. However, untypable rotavirus strains have been found in these years, with prevalences up to 27%, suggesting a possible spread of non-serotype 1 through 4 strains.

Child↗

PubMed1998

Identification of mutations in the rotavirus protein VP4 that alter sialic-acid-dependent infection.

To explore further the role of VP4 as the rotavirus cell attachment protein, VP7 monoreassortants derived from the sialic-acid-dependent simian strain RRV and from the sialic-acid-independent human strains D, DS-1 and ST-3 were tested for susceptibility of infectivity of neuraminidase-treated MA-104 cells. Infectivity of RRV x D VP7 and RRV x ST-3 VP7 monoreassortants decreased when sialic acid was removed from the cell surface. However, of three separate RRV x DS-1 VP7 monoreassortants tested, only one was sialic-acid-dependent. Sequence analysis showed that both sialic-acid-independent strains contained a single amino acid change, Lys to Arg, at position 187. In addition, sialic-acid-independent infectivity was seen in one of 14 RRV VP4 neutralization escape mutants tested, and this strain was found to have a Gly to Glu change at amino acid position 150. These results indicate that positions 150 and 187 of VP4 play an important role in early rotavirus-cell interactions.

Animals↗

PubMed1998

Antirotavirus immunoglobulin A neutralizes virus in vitro after transcytosis through epithelial cells and protects infant mice from diarrhea.

Rotaviruses are the major cause of severe diarrhea in infants and young children worldwide. Due to their restricted site of replication, i.e., mature enterocytes, local intestinal antibodies have been proposed to play a major role in protective immunity. Whether secretory immunoglobulin A (IgA) antibodies alone can provide protection against rotavirus diarrhea has not been fully established. To address this question, a library of IgA monoclonal antibodies (MAbs) previously developed against different proteins of rhesus rotavirus was used. A murine hybridoma "backpack tumor" model was established to examine if a single MAb secreted onto mucosal surfaces via the normal epithelial transport pathway was capable of protecting mice against diarrhea upon oral challenge with rotavirus. Of several IgA and IgG MAbs directed against VP8 and VP6 of rotavirus, only IgA VP8 MAbs (four of four) were found to protect newborn mice from diarrhea. An IgG MAb recognizing the same epitope as one of the IgA MAbs tested failed to protect mice from diarrhea. We also investigated if antibodies could be transcytosed in a biologically active form from the basolateral domain to the apical domain through filter-grown Madin-Darby canine kidney (MDCK) cells expressing the polymeric immunoglobulin receptor. Only IgA antibodies with VP8 specificity (four of four) neutralized apically administered virus. The results support the hypothesis that secretory IgA antibodies play a major role in preventing rotavirus diarrhea. Furthermore, the results show that the in vivo and in vitro methods described are useful tools for exploring the mechanisms of viral mucosal immunity.

Animals↗

PubMed1997

Poliovirus Sabin type 1 neutralization epitopes recognized by immunoglobulin A monoclonal antibodies.

Immunity to poliomyelitis is largely dependent on humoral neutralizing antibodies, both after natural (wild virus or vaccine) infection and after inactivated poliovirus vaccine inoculation. Although the production of local secretory immunoglobulin A (IgA) antibody in the gut mucosa may play a major role in protection, most of information about the antigenic determinants involved in neutralization of polioviruses derives from studies conducted with humoral monoclonal antibodies (MAbs) generated from parenterally immunized mice. To investigate the specificity of the mucosal immune response to the virus, we have produced a library of IgA MAbs directed at Sabin type 1 poliovirus by oral immunization of mice with live virus in combination with cholera toxin. The epitopes recognized by 13 neutralizing MAbs were characterized by generating neutralization-escape virus mutants. Cross-neutralization analysis of viral mutants with MAbs allowed these epitopes to be divided into four groups of reactivity. To determine the epitope specificity of MAbs, virus variants were sequenced and the mutations responsible for resistance to the antibodies were located. Eight neutralizing MAbs were found to be directed at neutralization site N-AgIII in capsid protein VP3; four more MAbs recognized site N-AgII in VP1 or VP2. One IgA MAb selected a virus variant which presented a unique mutation at amino acid 138 in VP2, not previously described. This site appears to be partially related with site N-AgII and is located in a loop region facing the VP2 N-Ag-II loop around residue 164. Only 2 of 13 MAbs proved able to neutralize the wild-type Mahoney strain of poliovirus. The IgA antibodies studied were found to be produced in the dimeric form needed for recognition by the polyimmunoglobulin receptor mediating secretory antibody transport at the mucosal level.

Animals↗

PubMed1996

Production and characterization of murine IgA monoclonal antibodies to the surface antigens of rhesus rotavirus.

Rotavirus is the single most important cause of severe diarrhea in humans and is diffuse in most animal species worldwide, and an understanding of the antigenic properties of the virus is essential to the design of rational vaccine strategies. To better understand the localization of viral epitopes involved in antibody-mediated neutralization of virus infectivity, we have orally immunized mice with live rhesus rotavirus (RRV) and generated a panel of hybridoma cell clones secreting IgA class monoclonal antibodies. A total of 12 neutralizing IgA MAbs to VP4 and VP7 proteins were studied for their epitope specificity and topographical relationships by hemagglutination-inhibition assays, neutralization assays, and competitive-binding assays with previously mapped MAbs. In addition, neutralization-escape virus mutants were selected and gene segments for each variant were cloned and sequenced. Two IgA MAbs were found to be directed to the antigenic region A of the VP7 protein at amino acid 94, and 10 MAbs were directed at the VP8 trypsin cleavage fragment of VP4. Five of the VP4-specific MAbs identified the same neutralization epitope on the RRV VP8 protein, not previously associated with RRV neutralization. All neutralization-escape variants selected by this antibody group contained mutations at amino acids 132- 135 of VP4. One IgA MAb selected for a mutation at amino acid 190 of VP4, and the corresponding viral mutant failed to agglutinate erythrocytes. This MAb mapped to an epitope recognized by 2 additional IgA MAbs. These results suggest that oral immunization of mice with RRV elicits an IgA immune response which is predominantly directed toward antigenic determinants on the VP8 portion of VP4. As a consequence, the route of immunization may alter immunodominant neutralization responses elicited to rotavirus.

Animals↗

PubMed1995

Immunogenicity, antigenicity, and protection efficacy of baculovirus expressed VP4 trypsin cleavage products, VP5(1)* and VP8* from rhesus rotavirus.

Rhesus rotavirus (RRV) VP4 trypsin cleavage product VP5(1)*, a truncated form of VP5*, was expressed in baculovirus and found by immunoprecipitation to be antigenically similar to VP5* on the virion. Immunization of mice with VP5(1)* elicited neutralizing antibody that was found to be cross-reactive with viruses representing P genotypes 1, 3, 4, 6, 7, and 8. Baculovirus expressed trypsin cleavage products, VP8* (amino acids 1-246) and VP5(1)* (amino acids 247-474), were tested for their ability to elicit a protective response in a murine model of passive protection. These results were compared to those obtained with baculovirus expressed RRV VP4. Dams immunized with baculovirus expressed RRV VP4 gave birth to pups protected from RRV virus challenge. Neither VP5(1)* nor VP8* was as effective at generating protective immunity as full length VP4. However, antibody to VP5(1)* was more effective than antibody to VP8* at mediating protection even though the neutralizing antibody titers as measured by hemagglutination inhibition and focus reduction neutralization were similar.

Animals↗

PubMed1995

Antigenicity, immunogenicity and passive protection induced by immunization of mice with baculovirus-expressed VP7 protein from rhesus rotavirus.

The major neutralization antigen VP7 of rhesus rotavirus (RRV) was expressed in a baculovirus recombinant system. The expressed VP7 showed the same molecular mass as native VP7, and was recognized by hyperimmune sera as well as neutralizing and non-neutralizing monoclonal antibodies (MAbs) raised against RRV. Intraperitoneal administration of the expressed VP7 in mice elicited the production of serum antibodies which were able to immunoprecipitate VP7 from RRV-infected cell lysates and to neutralize the virus in vitro. Sera from immunized mice competed for binding to RRV in an ELISA with both neutralizing and non-neutralizing MAbs specific for VP7. Using a passive protection model of rotavirus disease, vaccination of mice with the recombinant VP7 induced partial protection from infection. These results suggest that the baculovirus-expressed VP7 may be useful in priming a protective immune response to rotavirus infection.

Animals↗

PubMed1994

Oral immunoglobulins for treatment of acute rotaviral gastroenteritis.

OBJECTIVE: Preliminary evidence has been reported on the antirotavirus effect of human serum immunoglobulin administered orally. The aim was to see whether such treatment might be effective in rotavirus acute gastroenteritis. METHODS: A prospective, double-blind, placebo-controlled study was performed. Ninety-eight children admitted with acute gastroenteritis were enrolled and randomly assigned to groups A (treated) and B (control). Children in group A received a single oral dose of 300 mg/kg body weight of human serum immunoglobulin. Parameters of efficacy were clinical condition, frequency and consistency of stools, duration of diarrhea, duration of viral excretion, and length of hospital stay. Antirotaviral activity was determined in the immunoglobulin preparation by a specific neutralization assay. RESULTS: Seventy-one of the 98 children enrolled had rotaviral gastroenteritis; 36 belonged to group A. Children who received immunoglobulin had significantly faster clinical improvement of clinical condition and stool pattern than control children. Mean total duration of rotaviral diarrhea was 76 hours in group A and 131 in group B (P < .01). Viral excretion lasted 114 and 180 hours, respectively (P < .01). Hospital stay was significantly reduced in children in group A. Neutralizing antibodies against rotavirus were detected in the immunoglobulin preparation. CONCLUSION: Oral administration of immunoglobulin is associated with a faster recovery from acute gastroenteritis and should be given to children hospitalized with this illness.

Acute Disease↗

PubMed1992

Laboratory diagnosis of rotavirus infection in diarrhoeal patients by immunoenzymatic and latex-agglutination assays.

One hundred stool samples from children with acute diarrhoea were examined by six commercial latex and immunoenzymatic assays for the diagnosis of rotavirus infection in four different laboratories. Samples were also analyzed by solid-phase immune electron microscopy using a rabbit anti-group A rotavirus antiserum. With electron microscopy as a basis for comparison, sensitivity and specificity for the latex and ELISA assays varied from 91.1 to 92.9% and from 94.2 to 99.4%, respectively. Statistically significant differences were revealed in the confirmation rate of electron microscopy-negative samples between different commercial assays. Significant variability was also found between results obtained by the laboratories taking part in the study.

Antigens, Viral↗

PubMed1991

Antibodies to the trypsin cleavage peptide VP8 neutralize rotavirus by inhibiting binding of virions to target cells in culture.

Two distinct patterns of neutralization were identified by comparing the neutralization curves of monoclonal antibodies (MAbs) directed at the two surface proteins, VP4 and VP7, of rhesus rotavirus. VP7-specific MAbs were able to neutralize virus efficiently, and slight increases in antibody concentration resulted in a sharp decline in infectivity. On the other hand, MAbs to VP4 proved much less efficient at neutralizing rhesus rotavirus, and the fraction of infectious virus decreased gradually throughout a wide range of antibody concentrations. MAbs directed at VP8*, the smaller trypsin cleavage fragment of VP4, were shown to efficiently prevent binding of radiolabeled virions to MA104 cell monolayers, to an extent and at concentrations comparable to those required for neutralization of infectivity. Conversely, MAbs recognizing VP7 or the larger VP4 trypsin cleavage product, VP5*, showed little or no inhibitory effect on virus binding to cells. All MAbs studied were able to neutralize rotavirus that was already bound to the surface of cells. The MAbs directed at VP8*, but not those recognizing VP5* or VP7, were shown to mediate release of radiolabeled virus from the surface of the cells. With MAbs directed at VP7, papain digestion of virus-bound antibody molecules led to an almost complete recovery of infectivity. Neutralization could be fully restored by incubation of virus-Fab complexes with anti-mouse immunoglobulin G antiserum. Neutralization with MAbs directed at VP8* proved insensitive to digestion with papain as well as to the addition of anti-immunoglobulin antibodies.

Antibodies, Monoclonal↗

PubMed1989

Morphological changes in HAV-infected Frp/3 cells and immunolocalization of HAAg.

Electron and immunoelectron microscopic studies were carried out on HAV-infected Frp/3 cells. The infection led to a distinctive cytopathic effect (CPE) arising on day 3 up to the complete detachment of monolayers on day 7. Infected cells exhibited progressive modifications, beginning from the formation of long helical polyribosomes. Subsequently, hypertrophy, cisternal dilatation and degranulation of the RER could be observed. Furthermore, the formation of concentric membranous bodies (CMB), large myelin-like structures and annulate lamellae could be revealed at later times of infection. 24-27 nm virus-like particles were observed within cytoplasmic vesicles or outside extensively degenerated cells. Indirect immunoperoxidase staining were used to localize HAV antigen (HAAg) in thin sectioned infected Frp/3 cells. Vesicular inclusion bodies, often seen to contain electron-lucent particles, resulted darkly stained as well as tracts of the RER and myelin-like structures. Negatively stained preparations from cell lysates revealed small clusters of HAV particles which sometimes appeared to be still associated with residual membrane fragments. Our findings seem to suggest that HAV replication occurs in close association with cytoplasmic membranes and a direct involvement of the RER seems to be demonstrated.

Antigens, Viral↗

PubMed1989

Relationship between cytotoxic necrotizing factor production and serotype in hemolytic Escherichia coli.

We examined the relationship between serotype and cytotoxic necrotizing factor (CNF) production in 123 hemolytic strains of Escherichia coli isolated from both stools and extraintestinal infections. Of 76 strains producing both hemolysin (Hly) and CNF, 66 (87%) belonged to one of six serogroups (O2, O4, O6, O22, O75, and O83). In contrast, 47 E. coli strains producing Hly only belonged to 21 different O serogroups, and only 2 of these (O6 and O18ac) were widely represented. Generally, CNF-positive and CNF-negative hemolytic isolates were assigned to different O serogroups, with the exception of O6, often present in both categories of isolates. Serogroups O4 and O18ac were significantly more prevalent among strains from extraintestinal infections than among those from stools. In contrast, the Hly-positive, CNF-negative isolates, belonging to numerous less common serogroups, were hardly ever isolated from extraintestinal infections. Serological typing further confirmed that hemolytic isolates of E. coli may grossly be divided into two main populations on the basis of the ability to produce CNF. Examination of hemolytic E. coli for this property may also be useful in achieving a more detailed characterization of pathogenic clones.

Bacterial Outer Membrane Proteins↗

PubMed1989

Four-year study of rotavirus electropherotypes from cases of infantile diarrhea in Rome.

Rotavirus infections were detected in 210 of 675 children with acute diarrhea admitted to a major pediatric hospital in Rome from January 1982 through December 1985. Most of the patients with rotavirus infections were admitted during the winter season in both 1982 and 1985, whereas during the two intermediate years, cases occurred in all months. Among 84 rotavirus samples examined, 14 different electropherotypes were recognized, 2 of which largely predominated over the others. The two electropherotypes were particularly frequent in the 2 epidemic years, altogether accounting for 70.2% of the samples typed, and circulated in distinct periods. None of the viruses showed a short pattern of electrophoretic migration of the genome, indicating a minor involvement of subgroup I rotaviruses in hospitalization-requiring diarrheas occurring in the area surveyed.

Acute Disease↗