Inhibiting the NLRP3 inflammasome with MCC950 promotes non-phlogistic clearance of amyloid-ß and cognitive function in APP/PS1 mice.

Activation of the inflammasome is implicated in the pathogenesis of an increasing number of inflammatory diseases, including Alzheimer's disease (AD). Research reporting inflammatory changes in post mortem brain tissue of individuals with AD and GWAS data have convincingly demonstrated that neuroinflammation is likely to be a key driver of the disease. This, together with the evidence that genetic variants in the NLRP3 gene impact on the risk of developing late-onset AD, indicates that targetting inflammation offers a therapeutic opportunity. Here, we examined the effect of the small molecule inhibitor of the NLRP3 inflammasome, MCC950, on microglia in vitro and in vivo. The findings indicate that MCC950 inhibited LPS+Aß-induced caspase 1 activation in microglia and this was accompanied by IL-1ß release, without inducing pyroptosis. We demonstrate that MCC950 also inhibited inflammasome activation and microglial activation in the APP/PS1 mouse model of AD. Furthermore, MCC950 stimulated Aß phagocytosis in vitro, and it reduced Aß accumulation in APP/PS1 mice, which was associated with improved cognitive function. These data suggest that activation of the inflammasome contributes to amyloid accumulation and to the deterioration of neuronal function in APP/PS1 mice and demonstrate that blocking assembly of the inflammasome may prove to be a valuable strategy for attenuating changes that negatively impact on neuronal function.

Lower respiratory tract infections in Inuit infants on Baffin Island.

BACKGROUND: It has long been suspected that Canadian Inuit children suffer from frequent severe lower respiratory tract infections (LRTIs), but the causes and risk factors have not been documented. This study assessed the infectious causes and other epidemiologic factors that may contribute to the severity of LRTI in young Inuit children on Baffin Island. METHODS: A prospective case study was carried out at the Baffin Regional Hospital in Iqaluit, Nunavut, of infants less than 6 months of age, who were admitted to hospital between October 1997 and June 1998 with a diagnosis of LRTI. Immunofluorescent antibody testing was used to identify respiratory viruses, and enzyme immunoassay (EIA) and polymerase chain reaction (PCR) were used to test for Chlamydia trachomatis. Demographic and risk factor data were obtained through a questionnaire. RESULTS: The annualized incidence rate of admission to hospital for bronchiolitis at Baffin Regional Hospital was 484 per 1000 infants who were less than 6 months of age; 12% of the infants were intubated. Probable pathogens were identified for 18 of the 27 cases considered in our study. A single agent was identified for 14 infants: 8 had respiratory syncytial virus, 2 adenovirus, 1 rhinovirus, 1 influenza A, 1 parainfluenza 3 and 1 had cytomegalovirus. For 4 infants, 2 infectious agents were identified: these were enterovirus and Bordetella pertussis, adenovirus and enterovirus, cytomegalovirus and respiratory syncytial virus, and respiratory syncytial virus and adenovirus. C. trachomatis was not identified by either EIA or PCR. All infants were exposed to maternal smoking in utero, second-hand smoke at home and generally lived in crowded conditions. INTERPRETATION: Inuit infants in the Baffin Region suffer from an extremely high rate of hospital admissions for LRTI. The high frequency and severity of these infections calls for serious public health attention.

Toxic and nutrient element concentrations in soft tissues of zebra and quagga mussels from Lakes Erie and Ontario.

Zebra and quagga mussels were collected from Lakes Erie and Ontario in 1997 and the soft mussel tissues were analyzed for Ca, Cd, Cr, Cu, Fe, Hg, K, Mg, Mn, Mo, Na, Ni, Pb, Se, Sr, V and Zn. No consistent relationships were apparent when comparing element concentrations in soft mussel tissues and mussel type, size range or sampling location. Literature dealing with the absorption of metals by both mussel types is reviewed.

Mutational analysis of the promoter region of the porA gene of Neisseria meningitidis.

The porA gene encodes the class 1 outer membrane protein (OMP1) in Neisseria meningitidis and is under transcriptional control. Promoter regions of porA from different clinical isolates were sequenced and were found to differ in the number of guanosine residues in a poly(G) track located upstream of the -10 region. Isolates that did not express OMP1 had up to nine G residues in the poly(G) track or an adenosine residue within this poly(G) track. Using beta-galactosidase as a reporter gene, the transcriptional activities of the promoter regions of the porA gene from three strains, two of which do not express OMP1, were assayed in both Escherichia coli and N. meningitidis. Mutations in the poly(G) track were created by site-directed mutagenesis and promoter fusions were further analyzed in E. coli and N. meningitidis. The number of nucleotides in the poly(G) track influenced promoter activity: reduction of a poly(G) track of 12nt by one and by two guanosine residues reduced promoter activity. Within the poly(G) track, replacement of an adenosine residue by a guanosine residue increased the promoter activity; replacement of a guanosine residue by an adenosine residue decreased the activity. The similar transcriptional activities for the mutated promoters in E. coli and N. meningitidis are compatible with similar control mechanisms for transcriptional control in both organisms.

Sequencing of porA from clinical isolates of Neisseria meningitidis defines a subtyping scheme and its genetic regulation.

Subtyping Neisseria meningitidis by methods that rely on monoclonal antibody (mAb) reactivity results in an unusually high number of strains that are not subtypeable. To subtype 48 strains isolated (1993-1994) in the province of Quebec that were not subtypeable by mAb-based techniques, we used DNA sequencing of the variable regions of porA, a gene that encodes the class 1 outer membrane protein. We assigned subtypes to all the previously nonserosubtypeable isolates and identified some novel subtypes. Because our sequencing strategy included the promoter region of porA, different isolates were compared in their sequences of the porA promoter region. A poly(G) stretch lies between the -10 and -35 regions of the promoter; replacement of a G residue by an A residue in this region resulted in loss of expression of porA. No correlation was found between the number of G residues in the poly(G) stretch and the level of expression; a minimum of 10 G residues is required in this stretch for expression of porA. One isolate expressed no class 1 outer membrane protein because of the insertion sequence IS1301 in the coding region of porA. Another isolate did not express the protein owing to a frame-shift mutation within the coding region of porA. Sequencing of porA allowed assignments of subtypes to previously uncharacterized isolates and provided insights about the regulation of expression of this gene in N. meningitidis.

Acute-phase neurologic complications of Haemophilus influenzae type b meningitis: association with developmental problems at school age.

The purposes of this study were to describe the incidence of acute-phase neurologic complications in a sample of 126 children with Haemophilus influenzae type b meningitis, and to determine if these complications were associated with higher rates of learning and behavior problems at school age. Risks were assessed by comparing rates of adverse psychoeducational outcomes in the 53 children in the sample with complications to corresponding outcome rates in the 67 children who were free of neurologic complications and who did not have abnormal electroencephalograms (EEGs) or computed tomographic (CT) scans. Comparisons were made by means of logistic regression analysis. Twenty-nine children (23% of the sample) had seizures, 16 (13%) were comatose or obtunded, 15 (12%) had sensorineural hearing loss, 8 (6%) had hemiparesis, and 7 (6%) had cranial nerve deficits other than hearing loss. Relative to children without complications, those with complications had higher rates of grade repetition and substandard performance on neuropsychological and achievement testing. Adverse outcomes, however, consisted primarily of more subtle cognitive and learning problems; only two of the children in the sample obtained prorated IQ scores below 70. Sequelae were associated with persistent neurologic deficits and bilateral hearing loss, as well as with transient symptoms including seizures, coma, and hemiparesis. While study findings argue against adverse consequences for the vast majority of children treated for this disease, the results clarify learning and behavior outcomes and indicate which children are at greatest risk.

Parental willingness to enter a child in a controlled vaccine trial.

OBJECTIVE: To determine the reasons that motivate parents to enrol or not enrol their child in a randomized, controlled vaccine trial. DESIGN: Cross-sectional survey. SETTING: Offices of primary care physicians in Dartmouth, Nova Scotia, and Montreal, Quebec. PARTICIPANTS: At the 2 sites, parents of 2-month-old infants at their first immunization visit who had decided to enrol (221) or not enrol (208) their child in 2 randomized pertussis vaccine trials. OUTCOME MEASURES: Rates of enrolment in vaccine trials; attitudes about medical research; sources of information about pertussis. RESULTS: Enrolment rates were 68% and 43% at the 2 sites. All parents agreed to answer questions about their decision to enrol or not enrol their child. The most common concerns resulting in nonenrolment were extra immunization 54% (26/48) and blood procurement 42% (20/48). Parents who did enrol their children were motivated to participate by the desire to contribute to medical knowledge (77% [170/221]), the desire to help others (48% [106/221]) and by the participation of their family physician (54% [120/221]). The enrollees' major sources of information about pertussis was health professionals or study personnel rather than the media. CONCLUSIONS: Altruistic reasons motivate parents' decision to enrol a child in a randomized, controlled vaccine trial. Nonparticipating parents seem most concerned about painful procedures in the study. Parents' decisions regarding participation do not appear to be affected by adverse media attention regarding the purported adverse sequelae of pertussis vaccines.

Subtyping of Neisseria meningitidis strains isolated in Quebec, Canada: correlation between deduced amino acid sequences and serosubtyping techniques.

Routine serosubtyping of Neisseria meningitidis relies upon reactivity of whole cells to monoclonal antibodies (mAbs). This procedure is limited in providing maximum serosubtype information because some epitopes in whole cells are masked and because mAbs are currently unavailable for some epitopes. To address masking of epitopes in whole cells, we isolated outer membrane vesicles (OMVs) from nine representative meningococcal strains that were isolated (1991-1993) in the province of Quebec, Canada; the OMVs were used in enzyme-linked immunosorbent assay for reactivity to mAbs, and improved serosubtyping information was obtained. A recent proposal assigns subtypes based on deduced amino acid sequences in the variable regions of the class 1 outer membrane protein. This scheme maintains the subtyping nomenclature that is based on reactivity to mAbs by defining the sequences in the epitopes recognized by the mAbs. We used this technique to assign subtypes to the meningococcal strains isolated in Quebec. For the strains tested, serosubtyping using mAbs and subtyping based on deduced amino acid sequences were in complete agreement. Subtyping using deduced amino acid sequences is superior because it does not depend on the availability of mAbs.

Outer membrane proteins and serosubtyping with outer membrane vesicles from clinical isolates of Neisseria meningitidis.

The currently practiced protocol for routine serosubtyping of Neisseria meningitidis relies on reactivity of whole cells to monoclonal antibodies against the class 1 outer membrane protein (OMP) in ELISAs or dot-blots. This procedure, however, failed to yield serosubtyping information in 28% (48/174) of clinical isolates (1993-1994) in the province of Québec, Canada. These 48 strains were characterized by OMP profiles and ELISAs with outer membrane vesicles (OMVs). Forty out of the 48 strains expressed class 1 OMP, indicating that the inability to assign a serosubtype was not owing to the absence of the class 1 OMP. Of these, 15 (38%) were serosubtypable in ELISAs with outer membrane vesicles. Thus, 81% (141/174) of all meningococcal strains were serosubtypable with ELISAs using whole-cells or OMVs. Because the routinely used procedure for serosubtyping of meningococci is limited in providing serosubtype information, alternate procedures are proposed to obtain comprehensive information for epidemiological identification of this bacterium.

Biochemical mediators of meningeal inflammatory response to group B streptococcus in the newborn piglet model.

The meningeal inflammatory response to a heat-killed mutant unencapsulated strain of type III group B Streptococcus (GBS) was studied in a newborn piglet model. GBS (10(9) colony-forming unit equivalents) or saline (control) was inoculated intraventricularly. Serial cerebrospinal fluid measurements were done at baseline and over the course of the next 24 h for cytochemical changes and production of tumor necrosis factor (TNF) and prostaglandins. In separate experiments, we defined the time course of early changes during the first 6 h and dose response relationship over a range of inocula 10(6) to 10(9) colony-forming unit equivalents. The intraventricular inoculation of the heat-killed unencapsulated GBS induced marked leukocytosis and increased protein by 6 h. These changes were preceded by a several hundredfold increase in TNF (maximum at 2 h) and prostaglandins (maximum at 2-4 h). The early and sharp rise in TNF suggests its pivotal role in initiating the inflammatory cascade. The magnitude of the inflammatory response increased with increasing bacterial dose over the range studied. To study the effect of encapsulation of GBS in the induction of meningeal inflammation, we compared the response to the unencapsulated mutant strain with that to the encapsulated parent strain. The encapsulated strain produced much smaller inflammatory changes, and only with high doses of bacteria. The GBS cell wall appeared to be the primary bacterial product triggering inflammation. Intraventricular injection of the heat-killed unencapsulated GBS with exposed cell wall can serve as a valid model for studying neonatal meningitis.

Mercury content of small pan fish from New York State waters.

Yellow perch (Perca flavescens) and pumpkin seed (Lepomis gibbosus) were sampled from 16 waters in New York-State and analyzed for total mercury concentration. The levels of mercury in the fish were all well below the safe guideline for human consumption (1 ppm of mercury, fresh weight) of the U.S. Food and Drug Administration. Factors affecting the mobility, methylation and absorption of mercury by fish are discussed.

Urine testing in young febrile children: a risk-benefit analysis.

OBJECTIVE: To assess the relative risks and benefits of 10 potential urine testing strategies (compared with no testing) involving urinalysis and urine culture for children aged 3 to 24 months with fever but no focus of bacterial infection. DESIGN: Decision analysis based on the literature. The 10 testing strategies consist of five pairs; within each pair of strategies, one calls for urinalysis and urine culture of a clean-voided (bag) specimen, and urine culture, and in the other, the urine specimen is sent for culture only if the result of the urinalysis is abnormal. The five pairs differ in selectivity for testing: all children, girls only, temperature > or = 39 degrees C only, fever only (no respiratory or gastrointestinal symptoms), or temperature > or = 40 degrees C only. The results of the decision analysis are expressed as the preventive fraction (the proportion of cases prevented) for end-stage renal disease (ESRD) and hypertension, and as two risk/benefit (RB) ratios: the number of children tested per case of ESRD prevented (RB1), and the number of children with false-positive diagnosis and treatment of urinary tract infection per case of ESRD prevented (RB2). RESULTS: On the basis of the available evidence, none of the testing strategies succeeds in preventing the majority of cases of ESRD and hypertension (preventive fraction = 0.10 to 0.50), and all are associated with high ratios of children tested (RB1 = 4167 to 12,500) and false-positive diagnosis and treatment (RB2 = 563 to 1800) per case of ESRD prevented. A strategy of combined urinalysis and urine culture in children with temperature > or = 39 degrees C is associated with the most favorable RB profile: preventive fraction = 0.45, RB1 = 5556; RB2 = 776. Sensitivity analyses indicate that the relative ranking of the strategies is relatively robust in regard to alterations in the estimates of the sensitivity or specificity of the urinalysis, the relative risk of renal scarring associated with delayed diagnosis and treatment, and the risk of scarring-induced hypertension or ESRD. CONCLUSIONS: Up to 50% of the long-term sequelae of occult urinary tract infections in young febrile children appear preventable by urine testing, but even the most favorable strategies require testing of thousands of children, and unnecessarily treating hundreds, for every case prevented. Our analysis reveals those strategies with more favorable RB profiles and emphasizes the need for rapid and convenient urine tests with much higher sensitivity and specificity or the need for less aggressive management strategies for febrile infants and young children with urinary tract infection.

Parents' versus physicians' values for clinical outcomes in young febrile children.

OBJECTIVE: To compare how parents and physicians value potential clinical outcomes in young children who have a fever but no focus of bacterial infection. METHODS: Cross-sectional study of 100 parents of well children aged 3 to 24 months, 61 parents of febrile children aged 3 to 24 months, and 56 attending staff physicians working in a children's hospital emergency department. A pretested visual analog scale was used to assess values on a 0-to-1 scale (where 0 is the value of the worst possible outcome, and 1 is the value for the best) for 22 scenarios, grouped in three categories according to severity. Based on the three or four common attributes comprising the scenarios in a given group, each respondent's value function was estimated statistically based on multiattribute utility theory. RESULTS: For outcomes in group 1 (rapidly resolving viral infection with one or more diagnostic tests), no significant group differences were observed. For outcomes in groups 2 (acute infections without long-term sequelae) and 3 (long-term sequelae of urinary tract infection or bacterial meningitis), parents of well children and parents of febrile children had values that were similar to each other but significantly lower than physicians' values for pneumonia with delayed diagnosis, false-positive diagnosis of urinary tract infection, viral meningitis, and unilateral hearing loss. For bacterial meningitis with or without delay, however, the reverse pattern was observed; physicians' values were lower than parents'. In arriving at their judgment for group 2 and 3 scenarios, parents gave significantly greater weight to attributes involving the pain and discomfort of diagnostic tests and to diagnostic error, whereas physicians gave significantly greater weight to attributes involving both short- and long-term morbidity and long-term worry and inconvenience. Parents were significantly more likely to be risk-seeking in the way they weighted the attributes comprising group 2 and 3 scenarios than physicians, ie, they were more willing to risk rare but severe morbidity to avoid the short-term adverse effects of testing. CONCLUSIONS: Parents and physicians show fundamental value differences concerning diagnostic testing, diagnostic error, and short- and long-term morbidity; these differences have important implications for diagnostic decision making in the young febrile child.

Role of the complete blood count in detecting occult focal bacterial infection in the young febrile child.

Previous studies of the value of the complete blood count (CBC) in distinguishing viral from bacterial infection in young febrile children have failed to exclude children with clinically evident bacterial infection and thus have inflated the positive predictive value of the test for occult focal infection. We prospectively studied 2492 children 3-24 months of age who presented to a children's hospital emergency department between March 1989 and August 1990 with fever (> or = 38.0 degrees C) of acute (< or = 4 days) onset but no evident bacterial focus of infection, 433 (17.4%) of whom received a CBC. We also carried out an 8-year retrospective analysis to estimate prior, or pre-test, probabilities (prevalences) and examine CBC results for rare occult bacterial infections (meningitis, osteomyelitis, and septic arthritis). Estimated prior probabilities for the four most common categories of infection that can be diagnosed at the initial visit were: non-pneumonitic viral infection, 88.6% in boys and 86.0% in girls; pneumonia, 8.5% in both sexes; urinary tract infection (UTI), 3.0% in boys and 5.5% in girls; and bacterial meningitis, 0.0066% in both sexes. The likelihood (sensitivity) of a total white blood cell (WBC) count > or = 15,000/mm3 was 25.5, 64.5, 62.5, and 50.0% for viral infection, pneumonia, UTI, and meningitis, respectively. Among children with a high total white blood cell count, neither a total polymorphonuclear count > or = 10,000/mm3 nor a band count > or = 500/mm3 was associated with significantly elevated likelihoods for occult pneumonia or UTI, a finding confirmed by multiple logistic regression analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

The sequelae of Haemophilus influenzae meningitis in school-age children.

BACKGROUND: Previous data on the consequences of Haemophilus influenzae type b meningitis for school-age children have been inconsistent, and much of the information on risk factors has been inconclusive. The present study was designed to evaluate the sequelae of this disease with a protocol for the comprehensive assessment of neuropsychological function. METHODS: Ninety-seven school-age children (mean age, 9.6 years), each of whom had a school-age sibling, were recruited from a survey of the medical records of 519 children treated for H. influenzae type b meningitis between 1972 and 1984 (at a mean age of 17 months) at the children's hospitals of Toronto, Ottawa, and Montreal. Of the 97 children, 41 had had an acute neurologic complication. Sequelae were assessed by comparing the index children with their nearest siblings on the basis of standardized measures of cognitive, academic, and behavioral status. RESULTS: Only 14 children (14 percent) had persisting neurologic sequelae: sensorineural hearing loss in 11 (unilateral in 6 and bilateral in 5), seizure disorder in 2, and hemiplegia and mental retardation in 1. Although the total sample of index children scored slightly below the siblings in reading ability, the 56 children without acute-phase neurologic complications (58 percent) were indistinguishable from their siblings on all measures. The differences between the groups were small even for the 41 pairs in which the index child had had an acute neurologic complication (mean full-scale IQ, 102 for the index children vs. 109 for the siblings). Sequelae were also associated with lower socioeconomic status and a lower ratio of glucose in cerebrospinal fluid to that in blood at the time of the meningitis. Behavioral problems were more prominent in index boys than index girls and in those who were older at the time of testing, but sex and age were not related to cognitive or academic sequelae. CONCLUSIONS: We find a favorable prognosis for the majority of children who are treated for meningitis caused by H. influenzae type b.

Comparative studies of microscopically determined aggregation, degranulation, and light transmission after chemotactic activation of adult and newborn neutrophils.

Changes in the light transmission of suspensions of activated neutrophils are widely used to measure the dynamics of neutrophil aggregation. Such studies have suggested, for example, that aggregation is irreversible for human newborn neutrophils but fully reversible for adult cells. We have evaluated aggregation directly by microscopic particle counting and compared it with changes in light transmission (delta T) and with release from three granule subsets for neutrophils activated with N-formyl-methionyl-leucyl-phenylalanine (FMLP). Maximal increases in %T in response to 0.5 micromol/L FMLP were approximately 25% larger for newborn than for adult neutrophils, and were only partially reversible by 8 minutes, while %T increases for adult neutrophils were fully reversible. However, measurements of neutrophil aggregation using light microscopy showed that both newborn and adult neutrophils fully deaggregated. A further independence of delta T from aggregation was found by pretreating adult neutrophils with cytochalasin B (5 micrograms/mL) in the presence of 0.5% gelatin, a pretreatment that blocked FMLP-induced neutrophil aggregation while allowing large increases in %T and degranulation. In response to FMLP, newborn neutrophils released more enzyme from each granule subset than did adult neutrophils. Our results suggest that cellular events associated with neutrophil activation (other than aggregation) are implicated in light transmission responses and that these differ for adults and newborns. These results also suggest that reports of neutrophil aggregation should be based on direct particle counting methods rather than on %T responses.

Epiglottitis in Canada: A multiregional review.

Epiglottitis is an acute, life threatening infection usually caused by Haemophilus influenzae type b. Although antibiotic therapy is an important part of management, the optimal route and duration is unknown. A multicentre retrospective review of 305 children with epiglottitis was carried out in order to relate antibiotic therapy to hospital course and outcome, as well as to examine regional variation in patient demographics, clinical presentation and course of disease. A standardized form was used to extract data from hospital records. Although management varied significantly among the six centres in terms of mean duration of intubation (46 to 81 h), intravenous antibiotic therapy (3.8 to 5.7 days) and hospital stay (5.3 to 8.4 days), there were no significant centre-related differences in epidemiology, clinical course or outcome of epiglottitis. An extraepiglottic focus of infection was present in 15% of patients and included three with septic arthritis and one with meningitis. The duration of fever in hospital and maximum recorded temperature in hospital were significantly greater for children with extraepiglottic infection compared to those with epiglottitis alone. The data presented in this review suggest that most children with epiglottitis have an uncomplicated course and respond rapidly to antimicrobial therapy following airway securement. A short period of intravenous and oral antibiotic therapy is likely adequate for most children with epiglottitis. A well designed multicentre prospective trial is still needed to determine the optimal duration of antibiotic therapy.

Should blood cultures be obtained in the evaluation of young febrile children without evident focus of bacterial infection? A decision analysis of diagnostic management strategies.

The technique of decision analysis was used to compare the benefits (prevention of major infectious sequelae of bacteremia) and risks (unnecessary hospitalization and intravenous antibiotic treatment of children whose bacteremia would have resolved spontaneously, discomfort of venipuncture) of alternative diagnostic management strategies in the evaluation of children 3 to 24 months of age with fever (rectal temperature greater than or equal to 39 degrees C) of acute (less than or equal to 4 days) onset and without evident focus of bacterial infection. The diagnostic strategies compared at the initial visit were blood culture in all, blood culture in none, and selective blood culture (restricted to children judged to be at high risk). Probability estimates were based on published epidemiologic studies and case series, and utilities were elicited from mothers of 3- to 24-month-old children and from pediatricians. Based on initial probabilities and utilities, the "no blood culture" strategy had the highest expected utility, followed closely by the "selective blood culture" strategy, with the "blood culture all" strategy a distant third. Sensitivity analyses based on increased risk of major infectious sequelae or of bacteremia had no effect on the ranking of the three initial management options. Eliminating the "disutility" of venipuncture or augmenting the disutility of major infectious sequelae also failed to alter the ranking. Even when an extreme relative disutility for major sequelae was assumed, the "blood culture all" strategy was not favored. Thus, the risk of unnecessary hospitalization and intravenous antibiotic treatment of the relatively large number of children whose bacteremia spontaneously resolves appears to outweigh the benefit of preventing serious infectious sequelae in the few children in whom positive blood culture results permit timely intervention. The explicitness and coherence of the decision analysis approach should help in developing a rational diagnostic approach to the young febrile child.