Epidemiology of pneumococcal infections in Swedish children

Objective: This paper provides an overview of pneumococcal infections in Swedish children.
Method: Data supplied by the Swedish Institute for Infectious Disease Control (SMI) provided information on invasive pneumococcal isolates and on isolates with reduced susceptibility to penicillin. Disease burden was estimated from data collected in northern Stockholm and Malmöhus County. Results: Only 3–6% of the total number of invasive pneumococcal isolates came from children 0–15 years of age. Predominant serotypes in descending frequency were 7, 6, 14, and 23. Strains from all sources with reduced sensitivity to penicillin (MIC 0.5 mg/l) were found in 3% of children and varied between 0.2% and 11%, with the highest value found in Southern Sweden (predominating strains were 9, 19, 15, 6, and 23). A 10-year review of all cases of meningitis in Northern Stockholm reflected an incidence of 10/100000 (0–2 years) or 5.8/100000 (0–5 years), with severe sequelae occurring in 20% of children. This information can be used to predict an annual incidence of 30 cases of meningitis in Sweden.
Conclusion: The large proportion of serotype 7 among invasive isolates is distressing since this serotype is not represented in the present 7- and 9-valent protein-conjugated vaccines under development. However, the heptavalent vaccine, including serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F would (at a serotype level) provide coverage against 83% of the resistant isolates in Southern Sweden.     

Epidemiology of Haemophilus influenzae Type b Infections among Children in Denmark in 1985 and 1986

ABSTRACT. A retrospective epidemiological study of invasive Haemophilus influenzae type b infections among children in Denmark 1985 and 1986 was carried out and 226 cases were identified. Of these 93% occurred in patients younger than five, corresponding to an annual incidence of 40 cases per 100 000 children aged 0-4 years, 68% occurred in patients younger than two years of age, and 6% in patients younger than six months. The annual incidences of meningitis and epiglottitis were 27 and 8 cases, respectively, per 100000 children aged 0-4 years. Of the 156 cases with meningitis four patients died and seven had severe neurological sequelae. Only 67% of the cases of meningitis had been notified.     

Invasive Haemophilus influenzae type B diseases in Bangladesh, with increased resistance to antibiotics

OBJECTIVE: To determine the prevalence, age-group distribution, serotype, and antibiotic susceptibility patterns of invasive Haemophilus influenzae type b (Hib) isolates in Bangladeshi children because data regarding Hib diseases in developing countries are scarce, which has led to delay of the introduction of Hib vaccine in these countries. METHODS: Children diagnosed with meningitis (n = 1412) and pneumonia (n = 2434) were enrolled in this surveillance study for Hib invasive diseases. Cerebrospinal fluid (CSF) and blood specimens, and the subsequent isolates, were processed using standard procedures. RESULTS: During 1993 to 2003, 455 H influenzae strains were isolated from patients with meningitis (n = 425) and pneumonia (n = 30), and an additional 68 Hib meningitis cases were detected by latex agglutination (LA) testing. Overall, 35% of pyogenic meningitis cases were a result of H influenzae, 97.1% of which were Hib. Most (91.4%) cases occurred during the first year of life. Resistance to ampicillin, chloramphenicol, and cotrimoxazole was 32.5%, 21.5%, and 49.2%, respectively. There was a trend toward increasing resistance for all three drugs. Resistance to ampicillin and chloramphenicol was almost universally coexistent and was associated with increased sequelae compared with the patients infected with susceptible strains (31% [23/75] vs 11% [21/183]; P <.001). CONCLUSION: Hib is the most predominant cause of meningitis in young Bangladeshi children. Resistance to ampicillin and chloramphenicol and the high cost of third-generation cephalosporin highlight the importance of disease prevention through vaccination against Hib.     

Invasive Haemophilus influenzae type b infections in Singapore children: a hospital-based study

OBJECTIVE: A 6-year (1990-95) hospital-based retrospective study was carried out to investigate the pattern of invasive Haemophilus influenzae type b (Hib) disease. METHODOLOGY: Cases with Hib isolated from sterile sites (blood, cerebrospinal fluid, or joint aspirate) were identified from the hospital's microbiological records, and their reviewed case records. Patients with pyogenic meningitis in the same study period were also identified to estimate the incidence of Hib meningitis. RESULTS: Twelve patients had positive cultures from sterile sites, of whom nine children were less than 5 years of age. These included seven cases of meningitis, one patient with acute epiglottitis, and one case of pneumonia. Three of the seven patients with meningitis had significant long-term sequelae. Our data also suggests a relatively low proportion of ethnic Chinese children with invasive disease. It was estimated that 18.4% to 41.1% of pyogenic meningitis in children admitted to the National University Hospital were due to Hib. The estimated annual attack rate of invasive Hib disease was at most 3.3 per 100 000 children aged less than 5 years (95% confidence interval: 2.6-3.5/100 000). CONCLUSION:: Invasive Hib infections are relatively uncommon in our community. This justifies the need for a cost effectiveness study before a universal Hib vaccination program is implemented.     

Upper respiratory tract bacterial carriage in Aboriginal and non-Aboriginal children in a semi-arid area of Western Australia

BACKGROUND: Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis are associated with otitis media (OM). Indigenous children experience particularly high rates of OM. Few studies worldwide have described upper respiratory tract (URT) carriage in Indigenous and non-Indigenous children living in the same area. AIM: The aim of this study was to describe URT bacterial carriage in Aboriginal and non-Aboriginal children in the Kalgoorlie-Boulder area, Western Australia, as part of an investigation into causal pathways to OM. METHODS: Five hundred four and 1045 nasopharyngeal aspirates were collected from 100 Aboriginal and 180 non-Aboriginal children, respectively, followed from birth to age 2 years. Standard procedures were used to identify bacteria. RESULTS: Overall carriage rates of S. pneumoniae, M. catarrhalis and H. influenzae in Aboriginal children were 49%, 50% and 41%, respectively, and 25%, 25% and 11% in non-Aboriginal children. By age 2 months S. pneumoniae and M. catarrhalis had been isolated from 37% and 36% of Aboriginal children and from 11% and 12% of non-Aboriginal children, respectively. From age 3 months onward, carriage rates in Aboriginal children were 51% to 67% for S. pneumoniae and M. catarrhalis and 42% to 62% for H. influenzae; corresponding figures for non-Aboriginal children were 26% to 37% for S. pneumoniae and M. catarrhalis and 11% to 18% for H. influenzae. Non-Aboriginal children had higher carriage rates in winter than in summer, but season had little effect in Aboriginal children. Staphylococcus aureus carriage was highest under age 1 month (55% Aboriginal, 61% non-Aboriginal) and was always higher in non-Aboriginal than Aboriginal children. CONCLUSIONS: Interventions are needed to reduce high transmission and carriage rates, particularly in Aboriginal communities, to avoid the serious consequences of OM.     

Small bowel intestinal permeability in Australian aboriginal children

OBJECTIVE: To show that the severity of diarrheal disease in Aboriginal children in tropical Australia is a consequence of underlying small intestinal mucosal damage. STUDY DESIGN: A prospective study of 338 Aboriginal admissions compared to 37 non-Aboriginal children, both diarrhea cases and controls. Intestinal permeability was measured by lactulose-rhamnose (L/R) ratios on a timed 90-minute blood test. RESULTS: For diarrheal admissions, significantly more Aboriginal (vs. non-Aboriginal children) had hypokalemia (70 vs. 10%), acidosis (65 vs. 29%), moderate to severe dehydration (52 vs. 19%) and a longer mean length of stay (mean 8.9 vs. 3.9 days). Mean L/R ratios (95% confidence intervals) in Aboriginal children (diarrhea vs. controls) were 16.5 (14.6-18.7) vs. 4.5 (3.8-5.3) compared to 7.7 (4.4-13.3) vs. 2.5 (1.8-3.4), respectively, in non-Aboriginals. Abnormal permeability ratios (> 5.6) consistent with tropical-environmental enteropathy syndrome were found in 36% (27/75) of Aboriginal controls compared to none of the non-Aboriginal controls. On multiple regression, the factors associated with high L/R ratios were diarrheal severity ( < 0.001), acidosis ( = 0.007) and hypokalemia ( = 0.04). CONCLUSIONS: An underlying tropical-environmental enteropathy contributes to the severity of acute gastroenteritis in Aboriginal children. Diarrheal complications, such as acidosis, hypokalemia, and osmotic diarrhea are associated with high L/R ratios, reflecting greater small intestinal mucosal damage.     

Iron deficiency in Bourke children

Abstract A study of 121 Aboriginal and 91 non-Aboriginal children aged 6 years and under was carried out in Bourke during 6 months of 1986. These children were selected either because they were admitted to hospital and had an incidental blood test or were screened at various childcare and preschool facilities in the town. A haemoglobin level of below 100 g/l was found in 12.4% of Aboriginal children compared with only 3.3% of non-Aboriginal children. A mean corpuscular volume of less than 80 was found in 15.7% of Aboriginal children and 3.3% of non-Aboriginal children. Of the total sample, 17.4% of Aboriginal children and 6.6% of non-Aboriginal children had a serum ferritin level of less than 10 ng/ml. These markers of iron deficiency were associated with low weight and crowded living conditions in Aboriginal children. The prevalence of haemoglobin below 100 g/l among Aboriginal children under 5 years has fallen from 24.7% in 1971 to 14.1% in 1986.     

Invasive pneumococcal infection in children, 1981-92: A hospital-based study

Objective: To document the pattern and sequelae of invasive pneumococcal infection in hospitalized children.
Methodology Retrospective review of Streptococcus pneumoniae (Sp) isolates from normally sterile sites from 1981 to 1992 at three paediatric centres in Sydney for demographic data, spectrum of disease, predisposing conditions, mortality, and sequelae from meningitis.
Results: Four hundred and thirty-one episodes in 417 patients were identified. Foci of infection were: meningitis, 34%; pneumonia, 29%; bacteraemia without apparent focus, 30%; and other foci, 7%. Sixty-one per cent of all cases and 64% of cases with meningitis were less than 2 years old. Predisposing conditions were present in 37%, were significantly more common in patients over age 2 years and were more common with foci other than meningitis. Overall mortality was 6.6% whereas the mortality for those with meningitis was 8%. Neurological sequelae were identified in 34% of previously normal children, and severe hearing loss occurred in 11.5%.
Conclusions The high morbidity and mortality from invasive pneumococcal infection in children justifies further evaluation of preventive strategies.     

Diverging trends for lower respiratory infections in non-Aboriginal and Aboriginal children

AIM: To investigate temporal trends in admission rates for acute lower respiratory infections (ALRI) in a total population birth cohort of non-Aboriginal and Aboriginal children. METHODS: Retrospective analysis of linked population-based data using the Western Australian Data Linkage System. All singleton live births in Western Australia between 1990 and 2000 were included. Hospital admission rates per 1000 live births for ALRI before age 2 years and linear time trends for ALRI admission rates were investigated. RESULTS: ALRI admission rates were 7.5 (95% confidence interval (CI) 7.2-7.7) times higher in Aboriginal than non-Aboriginal children (337 vs. 45 per 1000 live births); pneumonia rates were 13.5 (95% CI 12.8-14.4) times higher and bronchiolitis rates were 5.8 (95% CI 5.3-6.0) times higher. ALRI admission rates rose in non-Aboriginal children (<12 months, 6%/year, P<0.002; 12-23 months, 11%/year, P<0.001) but declined in Aboriginal children aged 12-23 months (4%/year, P=0.003). Bronchiolitis rates rose in all children, especially non-Aboriginal infants aged <12 months (13%/year, P<0.001), while pneumonia rates rose in non-Aboriginal children but declined in Aboriginal children. Declines in bronchitis and asthma were also noted. CONCLUSION: There has been an increase in incidence of bronchiolitis before age 12 months. For children aged 12-23 months a diagnostic shift from asthma and bronchitis to bronchiolitis and changes in health service utilisation are likely explanations for diverging temporal trends. The continuing disparity between Aboriginal and non-Aboriginal children needs to be addressed and appropriate preventative measures for ALRI, and in particular bronchiolitis, are urgently needed.     

Behaviour is not really at risk after surviving meningitis in childhood

AIM: To examine behaviour problems, personality, self-perceived competence and academic deficits in children who had recovered from non-Haemophilus influenzae type b (Hib) bacterial meningitis (BM) without obvious medical sequelae. METHODS: Assessments in 182 children, mean age 10 (range 5-14) years, 4-10 years after surviving meningitis, were compared to scores of norm reference groups. RESULTS: More children were estimated to have academic deficits (27%) than behaviour problems as perceived by the parents (9%). The mean deviation from normal was absent to moderate on behaviour problems, personality variables and self-perceived competence. CONCLUSION: Children who survived non-Hib BM without severe medical sequelae hardly differ from normal children with respect to personality and self-perceived competence. A small proportion deviates from normal in behaviour problems.     

Iron deficiency in Bourke children

A study of 121 Aboriginal and 91 non-Aboriginal children aged 6 years and under was carried out in Bourke during 6 months of 1986. These children were selected either because they were admitted to hospital and had an incidental blood test or were screened at various childcare and preschool facilities in the town. A haemoglobin level of below 100 g/l was found in 12.4% of Aboriginal children compared with only 3.3% of non-Aboriginal children. A mean corpuscular volume of less than 80 was found in 15.7% of Aboriginal children and 3.3% of non-Aboriginal children. Of the total sample, 17.4% of Aboriginal children and 6.6% of non-Aboriginal children had a serum ferritin level of less than 10 ng/ml. These markers of iron deficiency were associated with low weight and crowded living conditions in Aboriginal children. The prevalence of haemoglobin below 100 g/l among Aboriginal children under 5 years has fallen from 24.7% in 1971 to 14.1% in 1986.     

Epidemiology of meningitis and bacteraemia due to Streptococcus pneumoniae in The Netherlands

In The Netherlands, accurate data on the epidemiology of pneumococcal meningitis are available through a clinical microbiology laboratory-based national surveillance of cerebrospinal fluid isolates. The Netherlands Reference Laboratory for Bacterial Meningitis receives isolates of about 80% of all meningitis cases and about 40% of bacteraemic cases. The incidence of pneumococcal meningitis has increased slowly from 1.0/100000 in 1990 to 1.5/100000 since 1996. The highest age-specific incidence of meningitis was observed in children <5y of age (8.2/100000 in 1999). Of all isolates, 35% were from children <5 y of age. The number of isolates from non-meningitis patients with bacteraemia increased considerably since the early 1990s, especially among the elderly. The highest incidence was found in 1996, probably owing to a relatively severe winter. During 1995–1999, pneumococcal meningitis in The Netherlands was caused mainly by serotypes 3, 6B, 7F, 9V, 14, 18C, 19F, and 23F. Of the cases in children <15y, almost half were caused by serotypes 6B, 14, 18C, and 19F. The serotypes present in the 23-valent polysaccharide and 7-valent conjugate vaccines accounted for 87% and 47% of all meningitis cases, respectively. Pneumococcal resistance to penicillin in The Netherlands is still low, at about 1%. Genotypically, resistant strains belong to many clones. Horizontal transfer of capsular genes occurs among these isolates. In The Netherlands, 45% of cases of pneumococcal meningitis have severe predisposing factors. The case-fatality rate was significantly higher among patients with impaired immunity than among those with a break in the integrity of the dura.     

Giardia carriage in Aboriginal and non-Aboriginal children attending urban day-care centres in South Australia

Abstract A survey of Giardia lamblia prevalence was carried out in Adelaide, South Australia, among Aboriginal and non-Aboriginal children attending day-care centres. A single-stool examination in 178 children aged 6 years and under revealed an overall prevalence rate of 10.7% with all carriers being 1-4 years of age. Within this age group, Giardia prevalence among Aboriginal children (11/32) was significantly higher than that among non-Aboriginal children (eight of 99) (Chi-square analysis, P > 0.001). Furthermore, among Aboriginal children, a significant association ( P > 0.05) was found between giardia carriage and the family's contact with rural Aboriginal settlements or people from these areas. Aboriginal children with no rural contact had a giardia prevalence similar to non-Aboriginal children.     

Detection of antigenuria for diagnosis of invasive Haemophilus influenzae type b disease

BACKGROUND: Haemophilus influenzae type b (Hib) diseases are responsible for an estimated 400,000 childhood deaths, mostly in developing countries. OBJECTIVES: To determine the value of the Wellcogen quantitative latex agglutination test (LA) in urine for the diagnosis of Hib pneumonia and meningitis. METHODS: Healthy and sick children aged <5 y were enrolled in Dhaka Shishu (Children's) Hospital. Boiled and non-concentrated urine specimens underwent LA testing. In vaccinated subjects, urine was tested by LA at 24 h, 4-6 and 7-10 d after vaccination. RESULTS: Of 1302 enrolled cases, 201 were healthy (90 Hib vaccine recipients and 111 provided NP) and 1101 were sick with either pneumonia (n=974) or meningitis (n=127). Among the healthy children enrolled, 41 (41/111, 37%) were colonised with Hib and two (2/41, 5%) were positive by LA test. Hib antigenuria among the children who had received Hib vaccination was mainly detected only on day 1 (7/90, 8%) of vaccination. Among the sick children, LA test for Hib antigen was positive for all confirmed cases of Hib pneumonia (10) and meningitis (35). In contrast, none of the urine specimens from the cases with a known aetiology other than Hib (n=104) was positive. Quantitative analysis of antigenuria of sick children showed that it is positive at least up to 1:8 and 1:16 dilutions for pneumonia and meningitis, respectively, in contrast with or=1:8 dilutions. CONCLUSIONS: The Wellcogen LA test for Hib using boiled and non-concentrated urine is more sensitive than blood culture alone and is highly specific.     

Epidemiology of invasive childhood pneumococcal infections in Greece

A retrospective study was conducted to identify the epidemiologic characteristics of invasive pneumococcal infections among children <14y of age in our geographic region. During a 5-y period, from 1995 to 1999, 590 cases of invasive pneumococcal infection were identified in Aghia Sophia Children's Hospital, Athens, Greece. The male to female ratio was 1.4:1 and 64% of patients were younger than 5 y of age. The overall annual incidence rate was estimated as 44/ 100000 children <14y of age, whereas the incidence rate for children <5y of age was 100/ 100000. The most common types of infections were pneumonia (472 cases; 133 definite and 339 probable), bacteraemia without focus (79 cases), and meningitis (33 cases). A seasonal variation of invasive pneumococcal infections was noted, with two peaks-one during spring and the other during autumn. Only two cases with meningitis died and one developed permanent neurological sequelae, representing a case-fatality rate for meningitis of 6%. Serogroups 14, 19, 6, 18, 23, 4 and 9 were the most prevalent, comprising 77% of 92 serotyped isolates.
Conclusion: Invasive pneumococcal infections cause considerable morbidity in the paediatric population in the Athens metropolitan area. Sixty-six percent of the serotypes causing invasive pneumococcal disease in our region are included in the 7-valent conjugate vaccine.     

The epidemiology of Haemophilus influenzae type b meningitis in Burkina Faso

BACKGROUND: Haemophilus influenzae type b (Hib) disease burden studies are important to conduct in African countries that plan to introduce vaccine so that vaccine impact can be documented. METHODS: We implemented population-based meningitis surveillance in 3 districts of Burkina Faso for 12 months each during 2002-2003 and 2004-2005 using polymerase chain reaction, culture and antigen detection. RESULTS: Lumbar puncture was performed on 1686 patients and 112 had Hib identified. Persons <1, <5, 5-14 and 15+ years of age had annual Hib meningitis incidences of 97, 34, 2.1 and 0.55 per 100,000, respectively; overall case fatality proportion was 25%. During the historic meningitis epidemic season months of December through April, the proportion of purulent cerebrospinal fluid among children aged <5 years that yielded Hib was 27% compared with 30% during other months. Twenty-five of 98 persons with information available were treated with only one or 2 doses of oily chloramphenicol. Among children age <5 years with Hib meningitis, 28% were pretreated with antimalarials and antimalarial pretreatment was associated with delay in hospitalization. CONCLUSIONS: In Burkina Faso, Hib meningitis incidence and case fatality proportion are high and thus vaccine could have a substantial impact. While awaiting well-implemented routine infant Hib vaccination, empiric case management for pediatric meningitis in sub-Saharan Africa must recognize that Hib is likely even during the epidemic season. In malaria-endemic areas, pediatric Hib meningitis case management may be adversely affected by the similar presentation of these 2 diseases.     

Giardia carriage in aboriginal and non-aboriginal children attending urban day-care centres in South Australia

A survey of Giardia lamblia prevalence was carried out in Adelaide, South Australia, among Aboriginal and non-Aboriginal children attending day-care centres. A single-stool examination in 178 children aged 6 years and under revealed an overall prevalence rate of 10.7% with all carriers being 1-4 years of age. Within this age group, Giardia prevalence among Aboriginal children (11/32) was significantly higher than that among non-Aboriginal children (eight of 99) (Chi-square analysis, P less than 0.001). Furthermore, among Aboriginal children, a significant association (P less than 0.05) was found between giardia carriage and the family's contact with rural Aboriginal settlements or people from these areas. Aboriginal children with no rural contact had a giardia prevalence similar to non-Aboriginal children.     

Infection is the major component of the disease burden in aboriginal and non-aboriginal Australian children: a population-based study

BACKGROUND: Infection accounts for the majority of pediatric mortality and morbidity in developing countries, but there are limited data on the infectious diseases burden in children from developed countries. We investigated reasons for hospitalization before age 2 years in a birth cohort of Western Australian Aboriginal and non-Aboriginal children. METHODS: Data on live births between January 1990 and December 2000, and corresponding deaths and hospitalizations in the first 2 years of life, were obtained through linked population-based data. RESULTS: Almost half the cohort of 270,068 children were hospitalized at least once. Aboriginal children had significantly higher admission rates (2196 vs. 779 per 1000 live births), stayed longer and were more likely to die in hospital than non-Aboriginal children. Infections (mainly respiratory and gastrointestinal) were the most common reason for hospitalization, accounting for 34% of all admissions, with higher rates in Aboriginal (1114 per 1000 live births) than non-Aboriginal children (242 per 1000) (P < 0.001). Over time, admission rates for infections declined in Aboriginal children but increased in non-Aboriginal children. Aboriginal children were admitted 14 times more often for pneumonia than non-Aboriginal children. CONCLUSIONS: Infections are the leading cause of hospitalization in children under 2 years of age. The continuing heavy burden of serious infections, borne disproportionately by Aboriginal children, needs to be alleviated. Public health interventions such as the development and universal implementation of vaccines for respiratory syncytial virus, rotavirus and influenza are needed, while adequate funding must be committed to Indigenous health services and training.