Prevalence of tuberculosis infection among teen-agers in Tuscany.

INTRODUCTION: In Tuscany, Tuberculosis incidence is more than triplicate from 1982 to the beginning of the third millennium. The impact of this trend on open population is not known, as updated studies on Tuberculosis prevalence are not available. Tuberculin skin test provides the currently most widely used tool for assessing Tuberculosis transmission in a community and the prevalence of infection as well. The objective of this investigation was the evaluation of tuberculin index by means of the Mantoux test in adolescents eighteen-years old. RESULTS: The study was carried out in 21 secondary schools of Siena and its Province; 1,138 students participated to this survey. The overall prevalence of subjects with a skin reaction size > 5 mm was 1.6%; if the standard cut-off of 10 mm was used, the overall prevalence of a positive skin reaction was 0.4%. Risk factors for a doubtful or positive reaction were previous immunization with BCG and migration from high-endemicity countries. DISCUSSION: In Italy, studies on tuberculin index in young adults are scanty and controversial: our results show a very low Tuberculosis prevalence and an epidemiological pattern typical of countries with low Tuberculosis endemicity. CONCLUSIONS: The slightly increase in Tuberculosis incidence has no impact on the prevalence of latent Tuberculosis infection on our geographical area. We conclude that skin-test screening for Tuberculosis should be addressed to high risk population as migrants from Countries reporting high transmission rate, those recently exposed to an infectious case and health-workers.

[Retrospective study of tuberculosis in the Province of Siena]. / Studio retrospettivo sui ricoveri per tubercolosi nella Provincia di Siena.

We report here the results of a retrospective study carried out on 200 tuberculosis cases admitted to the Hospital of Siena during the period 1994-2003. For each case, epidemiological, clinical and microbiological data were collected in order to analyze the trend of tuberculosis over the years and to compare our experience with similar studies. Indigenous patients were significantly older than immigrants (60.1 vs 34.2 yrs) more frequently affected by underlying chronic diseases. Overcrowding and HIV infection were predisposing conditions in 30 subjects (15% of cases) recently arrived from high endemicity countries. Pulmonary tuberculosis (TB) was diagnosed in 71% of cases, irrespective of origin. The death rate was 5%. Microbiological investigation was positive in 74.4% of examined subjects; 9.8% of isolates were resistant to one or more antituberculous drugs. The number of cases admitted to the Hospital seems to have slowly decreased in the last few years; factors that may influence this trend are discussed. Our results confirm a distinct epidemiological pattern of the disease between indigenous patients and immigrants, which is typical of low-endemicity countries. The delay in the diagnosis and management of the disease observed in this case-series report underlines the need to improve information on TB and skill in treatment, and to maintain specialized centres.

Epidemiology of streptococcus group A in school aged children in Pemba.

BACKGROUND: In Pemba (Zanzibar) all the risk factors which favour Group A Streptococci spreading, infections and late sequelae are present, though GAS epidemiology is unknown. OBJECTIVE: To determine the prevalence of GAS pharyngeal carriers among school-aged-children. DESIGN: Community-based cross sectional study, carried out at the end of the dry season (January-February 2001). SETTING: Eight primary schools over the four Pemba districts were included in the study. SUBJECTS AND METHODS: Two thousand two hundred and eighty six children aged 7-10 years were selected by random sampling and submitted to throat-swab after informed consent. Swabs were processed according to the "Lennette Manual of Clinical Microbiology" 7th Ed. Isolated were tested for antibiotic susceptibility toward penicillins, erythromycin, clindamycin, josamycin, cloramphenicol, levofloxacin, rifampin and tetracyclines. RESULTS: Twenty seven point six percent of school-aged children harboured beta-haemolytic Streptococci in their pharynx; most of the isolates were serologically identified as non Group A streptococci group C and G represented more than 70% of all strains, 38.8% of whom were identified as group G; the prevalence of group A streptococci carriers among healthy children all over the island was 8.6%; group A streptococci isolates were sensitive to all the antibiotic tested, except tetracyclines, towards which 83.2% of strains were resistant. CONCLUSION: This is the first research in the field of bacteriology carried out in Pemba. According to the epidemiology of group A streptococci and to the environmental and underlying factors which predispose to late group A streptococci sequelae, we suggest to consider antibiotic treatment for children presenting with sore throat with fever and swollen cervical lymphonodes without cough or coryza.

Toscana virus infections of the central nervous system in children: a report of 14 cases.

OBJECTIVE: To evaluate the pathogenicity of a recently discovered arthropod-transmitted bunyavirus (Toscana virus) on the CNS in children and to provide information on the epidemiologic and clinical aspects of Toscana virus infection. STUDY DESIGN: Case-series analysis of children hospitalized with clinical and cerebrospinal fluid examination compatible with a CNS disease of viral origin. METHODS: Cerebrospinal fluid, acute, and convalescent sera were investigated for conventional neurotropic viruses and for Toscana and tickborne encephalitis viruses. A clinical-epidemiologic analysis was carried out on confirmed Toscana virus cases to clarify the profile of Toscana virus infection in children. RESULTS: The study indicates that (1) Toscana virus has been endemic in the Siena province for at least 15 years; (2) the virus is responsible for at least 80% of acute viral infections of the CNS in children throughout the summertime; (3) the clinical signs and symptoms range from aseptic meningitis to meningoencephalitis; (4) infected children resided habitually or temporarily in rural or suburban areas of the Siena province, where ecological characteristics allow arthropods to be peridomestic in human settlements. CONCLUSIONS: Toscana virus is the most common viral agent involved in acute infections of CNS in children in central Italy.

Phlebotomus-transmitted toscana virus infections of the central nervous system: a seven-year experience in Tuscany.

Toscana virus (TOSv) is a recently discovered Phlebotomus-transmitted human pathogen involved in acute infections of the central nervous system (CNS) occurring during the summer in natural foci in Italy. The purpose of this prospective study was to investigate the role of this virus in 170 patients with meningitis-meningoencephalitis of suspected viral origin, admitted to the Departments of Infectious Diseases at the Siena Hospital from 1990 to 1996. Infections caused by tick-borne encephalitis virus (TBEv) and TOSv or other neurotropic viruses were routinely diagnosed by means of conventional virological methods. 89 cases were attributed to TOSv, about 10% of which were Europeans on vacation in Tuscany. All of the TOSv-positive cases were observed during the summer and were residents of hilly areas in Siena and its province at an altitude not above 500 m. An increase in the number of cases was observed over the years, with a higher incidence among younger people. The clinical picture was similar to that observed in other viral infections of the CNS. Evolution was benign in all cases; in 2 subjects symptoms and signs of encephalitis were present.

Evidence of Toscana virus infections without central nervous system involvement: a serological study.

In central Italy, acute lymphocytic meningitis and meningoencephalitis due to a Phlebotomus transmitted virus (Phlebovirus Toscana, TOSv) occurring throughout the summer are frequently observed. Several serum specimens of patients hospitalized with a clinical picture of viral meningitis/meningoencephalitis showed anti TOS-IgG reactivity suggestive of a previous infection occurring at an unknown time in the past. This observation led us to design a serological investigation of 83 household contacts of 46 summertime CNS infection patients (index cases) with the purpose of evaluating the percentage of both IgG and IgM in seropositive healthy individuals, living, like the index cases, in areas at high risk of phlebotomine sandfly bites. The serological study was carried out using an ELISA method: 22% of the sera showed a reactivity for anti-TOS IgG antibodies and 6% resulted IgG/IgM positive; none of them reported having had any symptoms of CNS involvement; the distribution of seropositive cases was similar in contacts of both TOS-confirmed and TOS-negative cases. Our results indicate: (1) that phlebovirus Toscana is frequently implicated in cases with CNS disease as well as in infections occurring without neurological involvement; (2) in our country the ecological requirements encompass the conditions in and around the human settlements for phlebotomine sandflies to become peridomestic thus amplifying the risk of TOSv infections, which are in fact widespread and frequent in Siena and its surroundings.

[Roseola infantum. Some epidemiologic, clinical and diagnostic aspects revisited. Personal experience]. / Esantema critico. Revisione su alcuni aspetti epidemiologici, clinici e diagnostici. Esperienza personale.

Seventy-five children aged less than 3 yrs, affected by Roseola infantum (maculopapular rash following an acute onset illness characterized by high fever for 2-5 days) were included in this study, 40% of them were admitted with urgency to our clinic for febrile convulsions. Several bacterial or viral agents other than HHV6 were isolated from more than 10% of the children; the role of HHV6 was studied with an immunofluorescence test (IFA) for specific antibodies (seroconversion); 25 single serum samples of the acute phase and 30 acute and convalescent paired sera were available; high positivity was shown in three preexanthematous samples; a serological evidence of HHV6 infection was obtained in only 9 of the 30 paired sera; a coinfection was shown in two subjects belonging to the last group; viral or bacterial agents other than HHV6, were demonstrated in 4 seronegative children. In our experience, the etiologic role of HHV6 in exanthema subitum is not always confirmed; we cannot explain the controversy of our results compared with those of Japanese literature.

Intrafamilial hepatitis A outbreak: projection on the community in an area of Tuscany.

In 1988, 3 intrafamilial cases of hepatitis A occurred in a little town in the nearby of Siena: shellfishes were probably responsible for the index case, close contacts for the two secondary cases, characterized by a very long incubation period (above 60 days). An inapparent infection was detected in one household contact. No other cases of hepatitis A have been observed in that area since the intrafamilial outbreak until now. A seroepidemiological survey was carried out in a group of persons living in the same area, and attending the same school or class-room of one of the secondary intrafamilial cases. 210 sera belonging to 105 teenagers were available; an IgG anti A test was performed on a double serum sample (before and after the outbreak): no seroconversion was observed. Our report underlines the hypoendemicity of hepatitis A infection in our country.

Development of immunoglobulin M-antibodies after rubella immunization with RA27/3 attenuated live vaccine in teen-agers: remaining problems.

Four-hundred-fourty-two rubella seronegative teen-agers living in Siena and the surroundings were vaccinated with RA 27/3 live attenuated rubella over a two years period (1985-1987). One-hundred-twenty seven vaccinees' sera were randomly selected for the rubella specific antibodies of the IgM class detection with two Elisa Methods; the sera were collected 10 and 30 days after the challenge; in 58 girls a serum sample was also obtained 1 yr later. None of the sera showed reactivity for RF. The comparison between the two Elisa methods gave satisfactory results, the percentage of discrepancies being low (3.9%). Ten days after the immunization the IgM positive sera were only 7.56% (Elisa Abbott) and 5.88% (Elisa Enzygnost Behringwerke). One month later, 86.61% of the specimens showed reactivity for specific IgM antibodies. None of 58 sera gave positive results after 1 yr. Rubella antibodies of the IgG class could be demonstrated in the "screening" sera of 3 IgM negative subjects, when an Elisa method was applied. Nine subjects (7%) repeatedly resulted IgM negative one month after the challenge although a seroconversion was observed using both HAI and EIA. A serum sample was also obtained in 6/9 IgM "non responders" after a rubella epidemic observed in 1988-1989; no subclinical reinfection due to the wild virus was detected in this group, no changes in HAI antibody title nor evidence of IgM class specific response were observed. Although most of the diagnostic aspects related with rubella and rubella vaccination appear to be resolved, it should be underlined that there are several remaining problems especially associated with IgM detection.

Decline of HBsAg antibodies after immunization with hepatitis B vaccines and after natural infection.

The long-term persistence of anti-HBsAg above 10 mUI is conventionally believed to protect against natural infection with hepatitis B virus, while it is not yet clear what is the clinical significance of the fall to below 10 mUI in antibody levels. In our opinion, an important method for evaluating the effectiveness of the vaccine lies in comparing the duration of vaccine-immunity with that following the disease, the later being held to provide life-long protection. In this view, we examined the sera samples of 69 subjects (56 healthy people, and 13 drug-addicts) previously affected from HBV infection looking for anti-HBsAg with an Elisa method. The subjects were aged between 4 months and 73 years and had all suffered from acute fully recovered icteric hepatitis in the previous 2 to 10 years. All the drug addicts (13 males) and 4 healthy children from the group had no or negligible levels of antibodies; 3 out of 8 old people (60 or more yrs old) showed no antibodies only 4-5 yrs after having been infected. In the remaining group of 44 healthy people 14 cases were observed which had antibody levels 10 mUI, regardless of age, sex or occupation; the greater the time between the infection and the test, the greater the probability of finding negligible antibody levels. We conclude that the reduction in antibody levels may not be indicative of a loss of immunity: many of our cases have shown low or undetectable antibody levels, a few years after full recovery from an acute attack of hepatitis B.

Impact of hepatitis A in Siena: a "traveller's disease"?

Over a period of seven years (from 1980 to 1987) 58 acute viral hepatitis A cases were admitted to the Departments for Infectious Diseases. This number represents 10.76% of all viral hepatitis patients. Most of the patients had travelled to foreign countries or to areas in Italy with high hepatitis A virus (HAV) circulation. An assessment of specific immunization against HAV in normal healthy people aged 1-60, performed by ELISA, showed a very low number of sero-positive subjects. The disappearance of HAV in Italy, which is similar to other western European countries, is probably due to the improved socio-economical conditions; the "imported cases" seem to have little impact on public health.

Seroepidemiological research on hepatitis A (HA) in the city of Siena.

The circulation of Hepatitis A Virus in the city of Siena and the tight neighbouring area appears to be fairly rare. In fact, the number of cases suffering from Hepatitis A, admitted into the Clinic of Infectious Diseases of the University of Siena, has been 33 out of 4,905 patients (yrs 1975-1985). Of these, only 6 were patients resident in Siena. Seroepidemiological research, carried out with the ELISA method on 275 people of an age between 1 and 20 years, has confirmed a specifically low immunization as regards to Hepatitis Virus A (in fact the total antibodies were present only in 1.54% of the cases tested). This report is a long way off the one indicated in other Italian cities in the south as well as the central north of Italy; it can be put in relation to the peculiar demographical situation of the city or to the general fall of Hepatitis A Virus infection also indicated in other areas of the world.

[Role of viruses in acute gastroenteritis]. / Inquadramento etiopatogenetico delle enteriti acute virali.

In a two years screening carried out on Florentine children we confirmed that Rotaviruses are the most important ethiological agents of acute gastroenteritis in infants less than two years old, irrespective of sex. We had evidence that Rotavirus diarrhea does not occur with the same incidence every year. Rotavirus gastroenteritis is characterized by profuse diarrhea, vomiting, fever and often by respiratory symptoms. Severe complications have not been observed.