Outbreak of type A foodborne botulism at a boarding school, Uganda, 2008.

Botulism has rarely been reported in Africa. In October 2008, botulism was reported in three Ugandan boarding-school students. All were hospitalized and one died. A cohort study was performed to assess food exposures among students, and clinical specimens and available food samples were tested for botulinum toxin. Three case-patients were identified; a homemade, oil-based condiment was eaten by all three. In the cohort study, no foods were significantly associated with illness. Botulinum toxin type A was confirmed in clinical samples. This is the first confirmed outbreak of foodborne botulism in Uganda. A homemade, oil-based condiment was the probable source. Consumption of homemade oil-based condiments is widespread in Ugandan schools, putting children at risk. Clinicians and public health authorities in Uganda should consider botulism when clusters of acute flaccid paralysis are seen. Additionally, schools should be warned of the hazard of homemade oil-based condiments, and take steps to prevent their use.

Dielectric relaxation of alpha -tocopherol acetate (vitamin E).

Dielectric loss spectra are reported for alpha -tocopherol acetate (an isomer of vitamin E) in the supercooled and glassy states. The alpha -relaxation times, tau_{alpha} , measured over a 190 degrees range of temperatures, T , at pressures, P , up to 400MPa can be expressed as a single function of TV3.9 ( V is specific volume, measured herein as a function of T and P ). At ambient pressure, there is no dynamic crossover over eight decades of measured tau_{alpha} . The relaxation spectra above the glass transition temperature T_{g} show ionic conductivity and an excess wing on the high-frequency flank of the alpha -relaxation loss peak. Temperature-pressure superpositioning is valid for the alpha process; moreover, the peak shape is constant (stretch exponent equal to 0.65). However, application of pressure changes the shape of the dielectric spectrum at higher frequencies due to the shift of the excess wing to form a resolved peak. Additionally, another relaxation process, absent at atmospheric pressure, emerges on the high-frequency side of the alpha -process. We propose that this new peak reflects a more compact conformation of the alpha -tocopherol acetate molecule. Drawing on the coupling model, the experimentally determined relaxation times, activation energy, and activation volume for the Johari-Goldstein process are compared to values calculated from the properties of the alpha relaxation. The agreement is generally satisfactory, at least for T

Adult botulism type F in the United States, 1981-2002.

BACKGROUND: Clostridium botulinum neurotoxin types A, B, and E cause most cases of the paralytic disease botulism. Little is known about the epidemiology, clinical features, or microbiology of botulism type F. METHODS: Cases of adult type F botulism were identified by review of data collected by CDC's National Botulism Surveillance System between 1981 and 2002. A case was either an individual whose serum or stool demonstrated type F toxin or whose stool culture yielded an organism producing toxin type F. A detailed review of cases' medical charts and laboratory data from CDC and local health departments was performed. RESULTS: Between 1981 and 2002, 1,269 cases of botulism among adults and infants were reported to CDC; 13 (1%) were adult type F. The median age of type F cases was 54 years; 7 (54%) were female. None were part of outbreaks. A toxigenic Clostridium baratii was identified in 9 (69%) of 13 cases. Among 11 cases for which clinical data were available, all required mechanical ventilation for a median duration of 17 days (range, 10 to 84); 8 (73%) were intubated within 24 hours of symptom onset. All patients had nearly complete or complete quadriplegia at the nadir of neurologic dysfunction, which occurred on average on day 5. On average by day 8, improvement in neuromuscular function was noted. The median duration of acute hospitalization was 31 days (range, 20 to 60). No deaths were reported. In only one case was a possible foodborne etiology identified. CONCLUSIONS: Toxigenic C baratii are the sole documented causes of type F botulism in the United States since 1981. These cases are characterized by a fulminant course with rapid progression to respiratory failure and paralysis, making early recognition and intervention critical to appropriate management.

Primary and secondary relaxations in bis-5-hydroxypentylphthalate.

Broadband dielectric spectroscopy was used to study the relaxation dynamics in bis-5-hydroxypentylphthalate (BHPP) under both isobaric and isothermal conditions. The relaxation dynamics exhibit complex behavior, arising from hydrogen bonding in the BHPP. At ambient pressure above the glass transition temperature T(g), the dielectric spectrum shows a broad structural relaxation peak with a prominent excess wing toward higher frequencies. As temperature is decreased below T(g), the excess wing transforms into two distinct peaks, both having Arrhenius behavior with activation energies equal to 58.8 and 32.6 kJmol for slower (beta) and faster (gamma) processes, respectively. Furthermore, the relaxation times for the beta process increase with increasing pressure, whereas the faster gamma relaxation is practically insensitive to pressure changes. Analysis of the properties of these secondary relaxations suggests that the beta peak can be identified as an intermolecular Johari-Goldstein (JG) process. However, its separation in frequency from the alpha relaxation, and both its activation energy and activation volume, differ substantially from values calculated from the breadth of the structural relaxation peak. Thus, the dynamics of BHPP appear to be an exception to the usual correlation between the respective properties of the structural and the JG secondary relaxations.

Effects of water on the primary and secondary relaxation of xylitol and sorbitol: implication on the origin of the Johari-Goldstein relaxation.

Dielectric spectroscopy was employed to study the effects of water on the primary alpha -relaxation and the secondary beta -relaxation of xylitol. The measurements were made on anhydrous xylitol and mixtures of xylitol with water with three different water concentrations over a temperature range from 173 K to 293 K. The alpha -relaxation speeds up with increasing concentration of water in xylitol, whereas the rate of the beta -relaxation is essentially unchanged. Some systematic differences in the behavior of alpha -relaxation for anhydrous xylitol and the mixtures were observed. Our findings confirm all the observations of Nozaki et al. [J. Non-Cryst. Solids 307, 349 (2002)]] in sorbitol/water mixtures. Effects of water on both the alpha - and beta -relaxation dynamics in xylitol and sorbitol are explained by using the coupling model.

Effect of pressure on dynamic heterogeneity in dendrimeric alkyd resin.

Broadband dielectric spectroscopy is employed to investigate the non-Debye relaxation behavior in a dendrimeric alkyd resin. From temperature-dependent measurements at ambient pressure, we found a very broad distribution of relaxation times. This is attributed to the complex geometrical topology of the molecule. However, compression significantly reduces the non-Debye character of the dielectric response; thus, pressure induces dynamic homogeneity in the dendrimeric alkyd resin.

Molecular subtyping of Clostridium perfringens by pulsed-field gel electrophoresis to facilitate food-borne-disease outbreak investigations.

Clostridium perfringens is a common cause of food-borne illness. The illness is characterized by profuse diarrhea and acute abdominal pain. Since the illness is usually self-limiting, many cases are undiagnosed and/or not reported. Investigations are often pursued after an outbreak involving large numbers of people in institutions, at restaurants, or at catered meals. Serotyping has been used in the past to assist epidemiologic investigations of C. perfringens outbreaks. However, serotyping reagents are not widely available, and many isolates are often untypeable with existing reagents. We developed a pulsed-field gel electrophoresis (PFGE) method for molecular subtyping of C. perfringens isolates to aid in epidemiologic investigations of food-borne outbreaks. Six restriction endonucleases (SmaI, ApaI, FspI, MluI, KspI, and XbaI) were evaluated with a select panel of C. perfringens strains. SmaI was chosen for further studies because it produced 11 to 13 well-distributed bands of 40 to approximately 1,100 kb which provided good discrimination between isolates. Seventeen distinct patterns were obtained with 62 isolates from seven outbreak investigations or control strains. In general, multiple isolates from a single individual had indistinguishable PFGE patterns. Epidemiologically unrelated isolates (outbreak or control strains) had unique patterns; isolates from different individuals within an outbreak had similar, if not identical, patterns. PFGE identifies clonal relationships of isolates which will assist epidemiologic investigations of food-borne-disease outbreaks caused by C. perfringens.

Outbreak of type A botulism and development of a botulism surveillance and antitoxin release system in Argentina.

CONTEXT: Botulism is an important public health problem in Argentina, but obtaining antitoxin rapidly has been difficult because global supplies are limited. In January 1998, a botulism outbreak occurred in Buenos Aires. OBJECTIVES: To determine the source of the outbreak, improve botulism surveillance, and establish an antitoxin supply and release system in Argentina. DESIGN, SETTING, AND PARTICIPANTS: Cohort study in January 1998 of 21 drivers of a specific bus route in urban Buenos Aires. MAIN OUTCOME MEASURE: Occurrence of botulism and implication of a particular food as the vehicle causing this outbreak. RESULTS: Nine (43%) of 21 bus drivers developed botulism, presenting with gastroenteritis, symptoms of acute cranial nerve dysfunction including ptosis, dysphagia, blurred vision, and motor weakness. One driver experienced respiratory failure. Type A toxin was detected from 3 of 9 patients' serum samples. All drivers received botulism antitoxin; there were no fatalities. Consumption of matambre (Argentine meat roll) was significantly associated with illness. Among 11 persons who ate matambre, 9 developed illness, compared with none of those who did not eat it (P<.001). The matambre had been cooked in water at 78 degrees C to 80 degrees C for 4 hours, sealed in heat-shrinked plastic wrap, and stored in refrigerators that did not cool adequately. Subsequently, a botulism surveillance and antitoxin release system was established. CONCLUSIONS: Insufficient cooking time and temperatures, storage in heat-shrinked plastic wrap, and inadequate refrigeration likely contributed to Clostridium botulinum spore survival, germination, and toxin production. A rapid-response botulism surveillance and antitoxin release system in Argentina should provide more timely distribution of antitoxin to patients and may serve as a model for other nations.

A modified enzyme-linked immunosorbent assay for measurement of antibody responses to meningococcal C polysaccharide that correlate with bactericidal responses.

The standardized enzyme-linked immunosorbent assay (ELISA) for measurement of serum immunoglobulin G (IgG) antibody responses to meningococcal C polysaccharide has been modified to employ assay conditions that ensure specificity and favor detection primarily of high-avidity antibodies. The modified and standard assays were used to measure IgG antibody concentrations in sera of toddlers vaccinated with meningococcal polysaccharide vaccine or a meningococcal C conjugate vaccine. The results were compared to the respective complement-mediated bactericidal antibody titers. In sera obtained after one or two doses of vaccine, the correlation coefficients, r, for the results of the standard assay and bactericidal antibody titers were 0.45 and 0.29, compared to 0.85 and 0.87, respectively, for the modified assay. With the standard assay, there were no significant differences between the geometric mean antibody responses of the two vaccine groups. In contrast, with the modified assay, 5- to 20-fold higher postvaccination antibody concentrations were measured in the conjugate than in the polysaccharide group. Importantly, the results of the modified assay, but not the standard ELISA, paralleled the respective geometric mean bactericidal antibody titers. Thus, by employing conditions that favor detection of higher-avidity IgG antibody, the modified ELISA provides results that correlate closely with measurements of antibody functional activity that are thought to be important in protection against meningococcal disease.

Age-dependent Neisseria meningitidis serogroup C class-specific antibody concentrations and bactericidal titers in sera from young children from Montana immunized with a licensed polysaccharide vaccine.

Neisseria meningitidis serogroup C bactericidal titers and class-specific enzyme-linked immunosorbent assay (ELISA) antibody concentrations were measured in sera from 173 children (1 to 5 years old) before and 6 weeks and 7 months following vaccination with a quadrivalent (A/C/Y/W-135) polysaccharide vaccine. The immune responses of the children were compared with those of 40 adults 6 weeks postvaccination. Both bactericidal titers and ELISA antibody concentrations were significantly higher in the adults than in the children (P < 0.05). In addition, the ratio of immunoglobulin G (IgG) to IgM was higher in the children than in the adults. With an ELISA total antibody concentration of >/=2 microg/ml used as a measure of seroconversion, >/=84% of the individuals from each age group responded to the serogroup C polysaccharide. However, with a >/=4-fold-increase in bactericidal titer used, only 18% of 1-year-olds, 32% of 2-year-olds, and 50 to 60% of 3-, 4-, and 5-year-olds seroconverted. The ELISA results suggest that >50% of all children retained >/=2 microg of total antibody per ml at 7 months postimmunization. However, the bactericidal titers suggest that <10% of children <4 years old retained a >/=4-fold increase at 7 months following vaccination. Of particular note, 59 of 79 sera (75%) from the 1- and 2-year-olds had high ELISA antibody concentrations (2 to 20 microg/ml) with no associated bactericidal titer (<1:8). Discordant results between bactericidal titers and ELISA antibody concentrations were not explained by the presence of IgA blocking antibody or relative levels of IgG and IgM. The bactericidal results show age-dependent differences in the production and retention of antibody in young children immunized with serogroup C polysaccharide; these differences are not evident with the ELISA data.

Standardization and a multilaboratory comparison of Neisseria meningitidis serogroup A and C serum bactericidal assays. The Multilaboratory Study Group.

A standardized serum bactericidal assay (SBA) is required to evaluate the functional activity of antibody produced in response to Neisseria meningitidis serogroup A and C vaccines. We evaluated assay parameters (assay buffer, target strains, growth of target cells, target cell number, complement source and concentration, and methods for growth of surviving bacteria) which may affect the reproducibility of SBA titers. The various assay parameters and specificity of anticapsular antibody to five serogroup A strains (A1, ATCC 13077, F8238, F9205, and F7485) and four serogroup C strains (C11, G7880, G8050, and 1002-90) were evaluated with Centers for Disease Control and Prevention meningococcal quality control sera. The critical assay parameters for the reproducible measurement of SBA titers were found to include the target strain, assay incubation time, and complement. The resulting standardized SBA was used by 10 laboratories to measure functional anticapsular antibody against serogroup A strains F8238 and serogroup C strain C11. In the multilaboratory study, SBA titers were measured in duplicate for 14 pairs of sera (seven adults and seven children) before and after immunization with a quadrivalent polysaccharide (A, C, Y, and W-135) vaccine. The standardized SBA was reliable in all laboratories regardless of experience in performing SBAs. For most sera, intralaboratory reproducibility was +/- 1 dilution; interlaboratory reproducibility was +/- 2 dilutions. The correlation between median titers (interlaboratory) and enzyme-linked immunosorbent assay total antibody concentrations was high for both serogroup A (r = 0.86; P < 0.001; slope = 0.5) and serogroup C (n = 0.86; P < 0.001; slope = 0.7). The specified assay, which includes the critical parameters of target strain, incubation time, and complement source, will facilitate interlaboratory comparisons of the functional antibody produced in response to current or developing serogroup A and C meningococcal vaccines.

Assignment of Neisseria meningitidis serogroup A and C class-specific anticapsular antibody concentrations to the new standard reference serum CDC1992.

A new standard meningococcal reference serum designated CDC1992 was prepared to replace meningococcal reference sera ECG and PB-2, which are not available in sufficient quantities for continued use as primary reference sera. CDC1992 was prepared from 14 healthy adult volunteers who underwent plasmapheresis 4 to 12 weeks postvaccination with a single dose of a Neisseria meningitidis quadrivalent polysaccharide vaccine. Total and/or class-specific meningococcal serogroup A and C anticapsular antibody concentrations (in micrograms per milliliter) were assigned to CDC1992 by using homologous and heterologous enzyme-linked immunosorbent assay (ELISA) formats. The reference serum ECG was used as a reference standard to assign total anticapsular antibody concentrations to CDC1992 by a homologous ELISA format. A heterologous ELISA format, with the Haemophilus influenzae type b standard reference serum FDA 1983, was used to assign total and class-specific antibody concentrations to CDC1992. Alkaline phosphatase-labeled mouse anti-human monoclonal antibody conjugates were used as secondary antibodies in both ELISA formats. The total, immunoglobulin G (IgG), IgA, and IgM antibody concentrations, assigned to CDC1992 for serogroup A were 135.8, 91.8, 20.1, and 23.9 micrograms/ml, respectively, and those for serogroup C were 32.0, 24.1, 5.9, and 2.0 micrograms/ml, respectively. Meningococcal serogroup A and C antibody concentrations were in good agreement when homologous and heterologous ELISA format results were compared. Total and class-specific serogroup A and C antibody concentrations were determined in six adult quality control serum samples from the Centers for Disease Control and Prevention by using the homologous ELISA and our assigned antibody concentrations for CDC1992. Antibody concentrations in reference sera ECG and PB-2 were measured in order to provide a historical link to previous studies. The general acceptance of CDC1992 as the standard reference serum and the assigned antibody concentrations will allow investigators to compare antibody levels in serum to those in a single reference preparation.

Determination of parallelism and nonparallelism in bioassay dilution curves.

There is a lack of consensus among investigators who use a variety of immunoassay techniques (e.g., enzyme-linked immunosorbent assay [ELISA] and radioimmunoassay) regarding the protocols for describing and forming standard reference or calibration curves and interpolating serum antibody concentrations. This confounds the issue of detecting the presence or absence of parallelism between standard reference serum and serially diluted serum sample curves. These curves must be parallel to support the assumption that the antibody-binding characteristics are similar enough to allow the determination of antibody levels in the diluted serum sample. There is no universal and widely adopted strategy for assessing parallelism in bioassays, and without an assurance of parallelism, investigators are not able to calculate reliable estimates for antibody concentrations in serum samples. Furthermore, single-point (dilution) serum assays do not provide information related to parallelism and nonparallelism, and this, too, may lead to considerable error when calculating antibody concentrations. When assay methodology, technique, and precision improve to the extent that standard reference serum and serially diluted serum sample curves are fit with little error, standard analysis of variance techniques are overly sensitive to negligible departures from parallelism. We present a series of guidelines that compose a protocol for assessing parallelism between bioassay dilution curves that are applicable to data derived from ELISAs. These criteria should be applicable, with minor modifications, to most immunoassay experimental situations and, most importantly, are not dependent on the mathematical model used to form the standard reference curve. These guidelines have evolved in our laboratories over the past 4 years during the performance of thousands of ELISAs for antibodies to the capsular polysaccharides of Neisseria meningitidis groups A and C and Haemophilus influenzae type b.

Multicenter comparison of Neisseria meningitidis serogroup C anti-capsular polysaccharide antibody levels measured by a standardized enzyme-linked immunosorbent assay.

A standardized enzyme-linked immunosorbent assay (ELISA) was used by 11 laboratories to measure levels of total serum antibody to Neisseria meningitidis serogroup C capsular polysaccharide in 16 unpaired pre- and postvaccination serum samples. Twelve serum samples were from adults, and four were from children aged 2, 3, 5, and 9. The between-laboratory coefficient of variation for pre- and postvaccination sera ranged from 16 to 59% and 11 to 21%, respectively. The average percent difference (absolute value) from the between-laboratory means for all prevaccination sera measured by each laboratory was 24%, whereas the average percent difference was 13% for all postvaccination sera. A postvaccination quality control serum was diluted three times to give optical densities on the high, middle, and low portions of the standard reference curve. The three dilutions were assayed by the 11 laboratories a total of 241 times and yielded an overall coefficient of variation of 20%. Antibody-binding inhibition curves showed that the standardized ELISA was specific for N. meningitidis serogroup C capsular polysaccharide antibody. Fifty percent inhibition of seven serum samples was obtained after reaction with an average concentration of 0.9 micrograms of meningococcal serogroup C polysaccharide per ml; an average of 93% inhibition was obtained with 50 micrograms of polysaccharide per ml. The acceptance and use of this standardized ELISA will reduce between-laboratory assay variability and ensure a more accurate and reproducible assessment of immunogenicity for vaccines under development.

[A case of Behcet's syndrome]. / Przypadek choroby Behceta.

The author reports a case of Behcet's disease in a girl aged 18 years with recurrent lesions of the oral and vulvar mucosa, eyes and nervous system. The disease had a recurrent character with a tendency for progressing deterioration. Treatment was unsuccessful and the patient died.