Prevalence of cytomegalovirus seropositivity in an urban childhood population in Cameroon.

In 1989, the prevalence of antibody to cytomegalovirus (CMV) was determined by the ELISA method in serum samples from 198 apparently healthy children 4-14 years old in Kumba City (Cameroon). Children were randomly recruited from six primary schools located in different districts of the city. The overall prevalence was 94.0%, increasing from 88.5% in 4-6 years old to 98% in subjects 11-14 years old. A slight male predominance was observed (96.2% versus 92.4%), which was not statistically significant. Family size and father's occupation were not associated with anti-CMV prevalence. These findings demonstrate a virtually total exposure to CMV infection by late childhood in Cameroon. However, the undesirable consequences of congenitally acquired CMV infection are rare, because nearly 100% of the women are seropositive by the time they reach childbearing age.

Seroepidemiology of pertussis in Italy.

During 1988 and 1989 the prevalence of serum IgG antibodies to pertussis toxin in a sample of 3,875 unvaccinated, apparently healthy persons between the ages of 1 year to 19 years was estimated by enzyme-linked immunosorbent assay. The participants were recruited by means of systematic cluster sampling from public and private schools in five geographic areas of Italy. The overall prevalence of IgG antibodies was 80.8%, with a steady increase from 33.5% among 1- to 3-year-old children to 95% among 17- to 19-year-old individuals. The prevalence of natural immunity was 50% and 75% at the ages of 4 and 6 years, respectively. No gender-related difference in immunity was observed. For children greater than 10 years of age, the seroprevalence of pertussis antibodies was significantly higher in northern regions than in southern regions until the age of 17-19 years, when the pattern reversed. There was no association of a child's immune status with the father's number of years of schooling or with family size. For children aged 1-3 years, serologic studies showed that the history of pertussis reported by parents in questionnaires was highly specific (97.6%) in predicting antibody status, with positive and negative predictive values of 90.5% and 79.2%, respectively. However, 20.8% of children had antibodies to pertussis toxin even though they had no history of whooping cough.

Immunity to diphtheria in the 3-19 year age group in Italy.

In Italy, immunization with diphtheria toxoid has been compulsory for all newborns since 1939. The last two clinical cases of diphtheria were reported in 1987. During the period 1987-1989, immunity against diphtheria was assessed by neutralization test in a random sample of 1740 healthy subjects 3-19 years old, from five geographical areas of Italy. Of the total population, 76.5% showed antibody levels considered to be protective (greater than or equal to 0.1 IU ml-1), 17.2% had a relative degree of protection (0.01-0.09 IU ml-1), and 6.3% lacked immunity (less than 0.01 IU ml-1). The percentage of unprotected subjects increased from 6.1% in the age group of 3-5 years to 11.4% in the age group of 18-19 years (p less than 0.01). A smaller proportion of males (5.3%) than of females (7.2%) was unprotected, but this difference was not statistically significant. Subjects residing in the south and the islands were more likely to be unprotected than those residing in the north (7.4 versus 4.1%, p less than 0.01). No association was found between lack of protective antibodies and family size (odds ratio 1.35, confidence interval 95% = 0.77-2.36). However, paternal education of less than 12 years was associated with a higher prevalence of non-responders. In order to maintain a high degree of immunity in the adult population, a routine adult booster dose of diphtheria toxoid is advisable.

Seroepidemiology of pertussis infection in an urban childhood population in Cameroon.

In 1989, the prevalence of IgG antibodies to pertussis toxin (PT) in a sample of 367 unvaccinated apparently healthy children 5-14 years old was estimated by ELISA in Kumba City (Cameroon). Children were recruited using a systematic random sampling from six primary schools located in different districts of the city. The sample was representative of the various socioeconomic classes. The overall prevalence was 75%; it increased from 62% in 5 year old children to 81% in children 12-14 years old (P less than 0.01). IgG antibody prevalence was positively related to the family size. Children belonging to households of nine or more members had a 2.2-fold risk (C.I. 95 per cent = 1.1-4.6) of previous exposure to B. pertussis infection. No association was found with the father's occupation (O.R. = 1). These findings demonstrate a great impact of pertussis infection in Cameroon, with a nearly total exposure by late childhood.

Changing patterns of hepatitis A virus infection in children in Palermo, Italy.

In 1988 in Palermo, Italy, the prevalence of antibodies to hepatitis A virus (anti-HAV) in a sample of 490 children 6-13 years old was 10.6%; it increased from 6.3% among children 6-10 years old to 14.7% in children 11-13 years old (P less than 0.01). Compared with findings from a survey conducted in 1978 in the same area, the results of the present study show a significant (P less than 0.01) reduction in the anti-HAV prevalence in both age groups. Anti-HAV prevalence was inversely related to the father's years of education and positively related to the family size. Children of fathers with less than 6 years of schooling had a 3.2-fold risk (C.I. 95% = 1.3-8.1), and children with five or more members in their households had a 2.7-fold risk (C.I. 95% = 1.1-6.4) of previous exposure to hepatitis A virus (HAV) infection. Our findings indicate that exposure of children in Palermo to HAV is decreasing significantly, probably because of improvements in socio-economic conditions during recent years; however socio-demographic factors appear to be important determinants of infection.

A comparative assay of epidemiological markers for Acinetobacter strains isolated in a hospital.

A comparative assay for epidemiological evaluation of three different Acinetobacter typing procedures, i.e. biotyping, phage-typing, and the analysis of the bacterial envelope protein profiles, was carried out using sixty-four multiresistant Acinetobacter strains isolated from clinical specimens. The antibiotic susceptibility of the strains was also considered. After geno-species identification, biotyping allowed the recognition of a relatively large and long-lasting presence, at an Intensive Therapy Unit, of two A. baumannii biotypes. Phage-typing and the analysis of the susceptibility to antibiotics allowed for the differentiation of strains belonging to different geno-species and biotypes, and in some cases also to the same biotypes. On the contrary, the analysis by polyacrylamide gel electrophoresis of the cell-envelope proteins failed to show any diversity not only within, but also between some of the biotypes of A. baumannii, the most prevalent species of the genus in the hospital environment.

SCP1-dependent Weigle activation of the VP5 phage in Streptomyces coelicolor A3(2).

The kinetics of induction of the UV-irradiated bacteriophage VP5 (Weigle reactivation) in Streptomyces coelicolor A3(2) strains with and without plasmid was investigated. Chloramphenicol (CAF) inhibits Weigle reactivation (WR) in UF strains (SCP1 absent) but not in SCP1+ strains of IF fertility (free plasmid). CAF, moreover, inhibits protein synthesis in non-irradiated UF and IF strains. In UV-irradiated IF strains, on the other hand, protein synthesis takes place irrespective of CAF. Weigle reactivation appears to require protein synthesis: the SCP1 plasmid, by protecting protein synthesis from CAF inhibition in UV-irradiated strains, allows WR. The proteins synthesized after UV induction during the pre-incubation period were investigated and the results suggest that a new UV-induced protein, coded by a gene localized on the plasmid, interacts with the cellular SOS system.