Industrial and simulation analysis of the nitrogen trichloride decomposition process in electrolytic chlorine production.

This work presents the dynamic simulation of the thermal decomposition of nitrogen trichloride (NCl(3)) during electrolytic chlorine (Cl(2)) production, using an industrial plant as a case study. NCl(3) is an extremely unstable and explosive compound and the decomposition process has the following main problems: changeability of the reactor temperature and loss of solvent. The results of this work will be used to establish a more efficient and safe control strategy and to analyze the loss of solvent during the dynamic period. The implemented model will also be used to study the use of a new solvent, considering that currently used solvent will be prohibited from commercial use in 2010. The process was simulated by using the commercial simulator Aspen and the simulations were validated with plant data. From the results of the simulation it can be concluded that the rate of decomposition depends strongly on the temperature of the reactor, which has a stronger relationship to the liquid Cl(2) (reflux) and gaseous Cl(2) flow rates which feed the system. The results also showed that the loss of solvent changes strongly during the dynamic period.

Seroprevalence of hepatitis B and C in the Western Brazilian Amazon region (Rio Branco, Acre): a pilot study carried out during a hepatitis B vaccination program.

In 1999, on the occasion of the application of the first vaccine dose during the state vaccination campaign against hepatitis B virus (HBV), 390 individuals from the town of Rio Branco, Acre, aged two or more years were selected for the determination of the seroprevalence of HBV and HCV. HBV markers (HBsAg, anti-HBs, and anti-HBc IgG) were determined on this occasion and anti-HBs antibodies were also assessed 30 days after the third vaccine dose. At the time of vaccination, 39% of the individuals were still susceptible to HBV, while 61% presented serologic evidence of previous HBV contact or previous vaccination. The individuals with previous HBV contact were significantly older (p<0.001) than those without HBV markers. Of the 192 individuals who returned for reexamination, 30 days after the third dose, 158 (82.3%) had received three vaccine doses, and only 60 (31.2%) belonged to the group without HBV markers. In these individuals, the seroconversion rate after the third dose was 92% (55/60). In conclusion, we found considerable HBV in this population, indicating the need for pursuing the immunization programs. We also found high rates of vaccination coverage in the Western Brazilian Amazon region.

Seroprevalence of hepatitis B and C in the Western Brazilian Amazon region (Rio Branco, Acre): a pilot study carried out during a hepatitis B vaccination program

In 1999, on the occasion of the application of the first vaccine dose during the state vaccination campaign against hepatitis B virus (HBV), 390 individuals from the town of Rio Branco, Acre, aged two or more years were selected for the determination of the seroprevalence of HBV and HCV. HBV markers (HBsAg, anti-HBs, and anti-HBc IgG) were determined on this occasion and anti-HBs antibodies were also assessed 30 days after the third vaccine dose. At the time of vaccination, 39 percent of the individuals were still susceptible to HBV, while 61 percent presented serologic evidence of previous HBV contact or previous vaccination. The individuals with previous HBV contact were significantly older (p<0.001) than those without HBV markers. Of the 192 individuals who returned for reexamination, 30 days after the third dose, 158 (82.3 percent) had received three vaccine doses, and only 60 (31.2 percent) belonged to the group without HBV markers. In these individuals, the seroconversion rate after the third dose was 92 percent (55/60). In conclusion, we found considerable HBV in this population, indicating the need for pursuing the immunization programs. We also found high rates of vaccination coverage in the Western Brazilian Amazon region.

Chronic ulcers and myasis as ports of entry for Clostridium tetani.

Evaluating tetanus immune status is not yet the usual clinical practice regarding patients with chronic ulcers or myasis. However, of 858 tetanus patients at Hospital Couto Maia (Salvador, Bahia, Brazil) aged 1 year or above, 2 had pressure ulcers and 17 had chronic ulceration of the lower limbs where these skin lesions were the ports of entry for Clostridium tetani. In these 19 cases, the following predisposing factors were described: venous insufficiency (n=6), sickle cell anemia (n=2), Hansen s disease (n=1), malnutrition (n=1), diabetes mellitus (n=1), trauma (n=1) and unknown factors (n=7). In 6 other cases, in addition to the Hansen s disease patient, the port of entry for tetanus was the site of extraction of Tunga penetrans larvae. In these 25 cases, the majority of patients (68%) were over 40 years old (17/25) and all of these patients stated that they had either not followed a tetanus toxoid vaccination regimen (19/25), or had partially completed such a regimen, or did not give precise information (6/25). Among the same series studied, over half (52%) of the patients died (13/25). We conclude that tetanus prevention must be included in the treatment of chronic skin ulcer patients, vaccination coverage should be increased among older people, and strategies aimed at improving coverage for all age groups must be reviewed.

[The immune state against yellow fever vaccinal virus (17D) in 2 populations of Bahia State, Brazil]. / Estado imune contra o vírus vacinal (17D) da febre amarela em duas populações do Estado da Bahia.

The occurrence of cases of yellow fever (YF) and also the extensive distribution of A. aegypti in Brazil, inspired a study about the estimate of immunity against vaccinal virus (17D) among the residents at two cities of the Bahia State, Ipupiara (n = 461) and Prado (n = 228). At this non-endemic area of YF, the search for serology antibody against 17D (Ab17D) and 18 another arbovirus was made thereby hemagglutination inhibition (HI). Only 1.2% (8/689) showed Ab17D, six of those with monotypic sort. The heterotypic sort for flavivirus (FLV) was interpreted as associated to immunity against 17D too, being much frequent in Prado (30.3%) than in Ipupiara (23.2%). The age > or = 50 years and residence in another states were related to seropositive for FLV, the same way that vaccination's history (17D). However, the history of vaccination presented low percentages of sensibility (< or = 45.4%) and predictive-positive value (< or = 38.4%), but high specificity (> or = 70.8%) and predictive-negative value (> or = 78.8%). Therefore, the frequency of residents with Ab17D was low (1.2%), although the higher frequency (25.5%) of antibody FLV carrier's, what signifies that 26.7% of the studied population should present protection against the YF virus.

[A dengue epidemic in Ipupiara and Prado, Bahia. A seroepidemiologic survey]. / Epidemia de dengue em Ipupiara e Prado, Bahia. Inquérito soro-epidemiológico.

Serologic studies in Brazil have indicated a 25% to 56% prevalence of dengue virus infections. However, these studies were carried out in populations of middle-sized and larger cities. The present study describes two epidemics of classic dengue fever in two small cities in the State of Bahia. The first occurred in 1987, in Ipupiara and was caused by dengue serotype-1 (DEN-1), the second occurred in 1995, in Prado and was caused by dengue serotype-2 (DEN-2). The laboratory diagnosis was made by the hemagglutination-inhibition test. 461 serum samples were collected in 1995 in Ipupiara (district of Chapada Diamantina) out of a population of 3,868 and 228 samples out of a total of 9,126 inhabitants of Prado (in the southernmost coastal region). The seropositivity of the samples was 11.9% (55/461) in Ipupiara and 17.5% (40/228) in Prado. These were no statistically significant differences as to age and sex between seropositive and seronegative individuals of the two cities studied. However, the seropositive cases in Ipupiara indicated a higher percentage (15.9% vs. 9.3%) of residency in or travel to other states of Brazil (p<0.03). Based on these data we estimate the occurrence of 460 and 1,597 cases of infection in Ipupiara and Prado, respectively. In conclusion, dengue virus infections in smaller cities probably have singular characteristics, since they exhibit a lesser prevalence of seropositivity caused by decreased breeding possibilities of Aedes aegypti.

Clonally related penicillin-nonsusceptible Streptococcus pneumoniae serotype 14 from cases of meningitis in Salvador, Brazil.

Active hospital-based surveillance in the city of Salvador, Brazil, from December 1995 through October 1998, identified 221 patients with confirmed pneumococcal meningitis. Of these 221 patients, 29 (13%) had isolates with intermediate-level resistance to penicillin. Infection with these penicillin-nonsusceptible isolates was significantly associated with age of <2 years (P<.0019), previous antibiotic use (P<.0006), and coresistance to trimethoprim-sulfamethoxazole (P<.0000). Serotype 14 was the most prevalent serotype (55.2%) of penicillin-nonsusceptible isolates. Strain typing by repetitive element BOX polymerase chain reaction (PCR) analysis showed that penicillin-nonsusceptible serotype 14 isolates had closely related BOX PCR patterns, whereas penicillin-susceptible serotype 14 isolates each had distinct, unrelated patterns. Penicillin-nonsusceptible serotype 14 isolates from Salvador and other Brazilian cities had similar BOX PCR patterns. These observations indicate that in Brazil a large proportion of cases of penicillin-nonsusceptible pneumococcal meningitis appear to be caused by a closely related group of serotype 14 strains that may have disseminated to widely separate geographic areas.

[Outbreak of American cutaneous leishmaniasis in Canoa, Santo Amaro, Bahia, Brazil]. / Surto de leishmaniose tegumentar americana em Canoa, Santo Amaro, Bahia, Brasil.

An outbreak of American cutaneous leishmaniasis (ACL) was detected in the village of Canoa in 1993. A prospective observational study was outlined to determine the frequency rates and to clinically characterize the disease. A total of 555 people were followed up. There were 29 cases of ACL, 11 cases of probably previous ACL (scars) and 529 healthy individuals. Of these 529 individuals, 65 had a positive Montenegro reaction without any present or past evidence of leishmaniasis. The prevalence of ACL during the two years was 5.2% (29/555). The leishmania involved was Leishmania braziliensis and the vector, Lutzomyia intermedia. Evidence of infection was detected in dogs and horses. The high frequency of the disease among children under ten years, the similar sex distribution of cases and a component of familial aggregation suggest a peri- or intra-domiciliary transmission.

[Anti-Hantavirus antibodies in school children in Salvador, Bahia]. / Anticorpos anti-hantavírus em escolares de Salvador, Bahia.

Hantavirosis are emerging diseases in the Americas. Although considered rare in children, among the five cases diagnosed in Brazil, one was in this age group. To know the serum-prevalence of hantavirosis in the pediatric group (schoolchildren) of low social economic level in Salvador, Bahia State, and to associate demographic, socio-economic and environmental factors to the serologic results, a standard questionnaire was applied and blood samples were collected from 379 students of two public schools. Sera were tested by indirect Immunofluorescent Antibody (IFA) IgG for Hantaan Virus (HTN) and Immunoenzymatic test (ELISA) for Sin Nombre viruses. Ages varied from five to seventeen years with a mean age of 10.2 years. The proportion of sera positive to HTN virus was 13.2%, and there were no positive antibodies to SN virus. The frequency of positivity was higher in the older group, similar among sexes and racial groups, and there was no association with the exposure to urban rodents. The antibodies anti-HTN serum-prevalence in low social economic level school children is high and confirm the circulation of hantaviruses in Salvador-Bahia, Brazil; the nonobservation of antibodies anti-SN indicates that the species are other than Sin Nombre Virus.

Anticorpos anti-hantavírus em escolares de Salvador, Bahia / Anti-Hantavirus antibodies in school children in Salvador, Bahia

Hantavirosis are emerging diseases in the Americas. Although considered rare in children, among the five cases diagnosed in Brazil, one was in this age group. To know the serum-prevalence of hantavirosis in the pediatric group (schoolchildren) of low social economic level in Salvador, Bahia State, and to associate demographic, socio-economic and environmental factors to the serologic results, a standard questionnaire was applied and blood samples were collected from 379 students of two public schools. Sera were tested by indirect Immunofluorescent Antibody (IFA) IgG for Hantaan Virus (HTN) and Immunoenzymatic test (ELISA) for Sin Nombre viruses. Ages varied from five to seventeen years with a mean age of 10.2 years. The proportion of sera positive to HTN virus was 13.2%, and there were no positive antibodies to SN virus. The frequency of positivity was higher in the older group, similar among sexes and racial groups, and there was no association with the exposure to urban rodents. The antibodies anti-HTN serum-prevalence in low social economic level school children is high and confirm the circulation of hantaviruses in Salvador-Bahia, Brazil; the nonobservation of antibodies anti-SN indicates that the species are other than Sin Nombre Virus.

As hantaviroses são doenças emergentes nas Américas e, em todo o mundo, os casos clínicos descritos foram infreqüentes entre crianças. O objetivo de investigar a freqüência de escolares portadores de anticorpos (IgG) anti-hantavírus justifica-se porque poucos estudos soroepidemiológicos pesquisaram a infecção por hantavírus no grupo pediátrico. Nos espécimes séricos de 379 escolares, de duas Escolas públicas da cidade do Salvador, Bahia, foram pesquisados os anticorpos anti-Hantaan (HTN) e anti-Sin Nombre (SN). A soropositividade de anticorpos anti-HTN foi de 13,2% (50/379) e todos os escolares foram soronegativos para o vírus SN. A soropositividade anti-HTN aumentou proporcionalmente com a idade. Não houve associação entre a soropositividade anti-HTN e as características relacionadas à exposição a roedores urbanos. A soroprevalência de anticorpos anti-HTN nos escolares estudados foi elevada e reforçou a hipótese de circulação de hantavírus em Salvador. A não observação de portadores de anticorpos anti-SN indica, provavelmente, a circulação de outros sorotipos nesta região, mais relacionados antigenicamente ao sorotipo Hantaan.

[HTLV-I/II infection in the state of Bahia]. / Infecção pelo HTLV-I/II no Estado da Bahia.

The city of Salvador, capital of Bahia, presents a population with the highest prevalence of HTLV-I infection in Brazil. Until now, only one study has investigated this infection in other cities of this state, even though by using a small sample. With objective to evaluate the prevalence of HTLV-I/II antibodies in four cities of the state of Bahia. Serum samples from 1,539 individuals who lived in Catolândia, Ipupiara, Jacobina and Prado were screened by ELISA, and repeatedly reactive samples confirmed by Western Blot. Forty-seven (3.1%) samples were positive by ELISA, and 44 of them were tested by Western blot: 5 (0.3%) were positive, 8 (0.5%) were indeterminate (all of them from Jacobina) and 31 were negative. The overall prevalence of HTLV-I antibodies was 0.3%. This prevalence varied from 0.0% (Prado) to 0.7% (Jacobina), but differences were not statistically significant (p > 0.21). None of these individuals presented HTLV-II antibodies. Jacobina showed the highest prevalence of HTLV-I infection among the cities studied, although the overall prevalence was low. In conclusion, further epidemiological, clinical and virological studies will be of paramount importance to obtain a better understanding of the natural history of this infection in Jacobina.

Infecção pelo HTLV-I/II no Estado da Bahia / HTLV-I/II infection in the state of Bahia

A cidade do Salvador, capital do Estado da Bahia, apresenta a população com maior prevalência da infecção pelo HTLV-I no Brasil. Todavia, somente um estudo incluiu uma cidade do interior deste Estado, mesmo assim com número amostral pequeno. O objetivo foi o de avaliar a prevalência de anticorpos anti-HTLV-I/II na população de quatro cidades do interior do Estado da Bahia. As amostras de soro proveninentes de 1.539 indivíduos residentes em Catolândia, Ipupiara, Jacobina e Prado foram triadas através do ELISA, e a confirmação dos resultados nas amostras repetidamente positivas foi realizada através do "Western blot". Quarenta e sete (3,1%) amostras foram positivas pelo ELISA, e 44 destas foram submetidas ao Western blot, com 5 resultados positivos (0,3%), 8 (0,5%) indeterminados (todos da cidade de Jacobina) e 31 negativos. A prevalência geral de anticorpos anti-HTLV-I, nas cidades estudadas, foi de 0,3%. Esta prevalência variou de 0,0% (Prado) a 0,7% (Jacobina), porém não houve diferença estatisticamente significante (p > 0,21). Nenhum indivíduo apresentou anticorpos anti-HTLV-II. Em conclusão, a prevalência da infecção pelo HTLV-I no interior do Estado da Bahia foi baixa, contudo, a população da cidade de Jacobina apresentou a maior prevalência. No entanto, outros estudos epidemiológicos, clínicos e virológicos serão necessários para a melhor compreensão da história natural desta infecção em Jacobina.

The city of Salvador, capital of Bahia, presents a population with the highest prevalence of HTLV-I infection in Brazil. Until now, only one study has investigated this infection in other cities of this state, even though by using a small sample. With objective to evaluate the prevalence of HTLV-I/II antibodies in four cities of the state of Bahia. Serum samples from 1,539 individuals who lived in Catolândia, Ipupiara, Jacobina and Prado were screened by ELISA, and repeatedly reactive samples confirmed by Western Blot. Forty-seven (3.1%) samples were positive by ELISA, and 44 of them were tested by Western blot: 5 (0.3%) were positive, 8 (0.5%) were indeterminate (all of them from Jacobina) and 31 were negative. The overall prevalence of HTLV-I antibodies was 0.3%. This prevalence varied from 0.0% (Prado) to 0.7% (Jacobina), but differences were not statistically significant (p > 0.21). None of these individuals presented HTLV-II antibodies. Jacobina showed the highest prevalence of HTLV-I infection among the cities studied, although the overall prevalence was low. In conclusion, further epidemiological, clinical and virological studies will be of paramount importance to obtain a better understanding of the natural history of this infection in Jacobina.

Evidências sorológicas da circulação do arbovírus Rocio (Flaviviridae) na Bahia / Serological evidence of the circulation of the Rocio arbovirus (Flaviviridae) in Bahia

Oito casos com anticorpos anti-Rocio são descritos, de quatro cidades do Estado da Bahia, sendo seis portadores de anticorpos IgG (IH e TN) e dois IgM (ELISA e TN). Os autores comentam sobre a circulação deste arbovírus no Estado, e as possibilidades de reações cruzadas com outros vírus antigenicamente relacionados.

Eight antibody anti-Rocio cases, from four distinct cities in the state of Bahia, are described; six of them being carriers of the antibody IgG (HI and NT) and two IgM (ELISA and NT). The authors comment on the circulation of these arboviruses in the state of Bahia and on the possibility of cross reactions with other antigenically related viruses.

[Serological evidence of the circulation of the Rocio arbovirus (Flaviviridae) in Bahia]. / Evidências sorológicas da circulação do arbovírus Rocio (Flaviviridae) na Bahia.

Eight antibody anti-Rocio cases, from four distinct cities in the state of Bahia, are described; six of them being carriers of the antibody IgG (HI and NT) and two IgM (ELISA and NT). The authors comment on the circulation of these arboviruses in the state of Bahia and on the possibility of cross reactions with other antigenically related viruses.

Antibody response to Salmonella typhi in human schistosomiasis mansoni.

Antibody response to Salmonella typhi O and H antigens was evaluated in 24 individuals with either hepatointestinal or hepatosplenic schistosomiasis mansoni before and after typhoid vaccination, and compared with that of non-infected controls. Before vaccination, Schistosoma-infected patients showed a higher frequency of positive antibody to O antigen and the same frequency to H antigen when compared with that of healthy individuals. However, those with hepatosplenic schistosomiasis showed higher titres of antibody to H antigen than those with hepatointestinal disease or healthy individuals. Infected subjects, particularly those with hepatointestinal disease, showed a decreased response after typhoid vaccine. This diminished ability to mount an immune response towards typhoid antigens during schistosomiasis may interfere with the clearance of the bacteria from blood stream and, therefore, play a role in the prolonged survival of salmonella as observed in some patients with chronic salmonellosis associated with schistosomiasis.

[An anti-Listeria seroepidemiological study in Uberaba, MG]. / Inquérito soro-epidemiológico antilistéria em Uberaba, MG.

From a total of 445 individuals, 17.1% had antibodies against L. monocytogenes detected by the agglutination tube test. They were separated in seven groups: bloods donnors (n = 50), Hospital visitors (n = 40), frigorific workers (n = 28), aviculture workers (n = 87), herdsman (n = 31), agriculture students (n = 60) and street-sweepers (n = 51). L1/2a serotype was predominant. Individuals from urban areas (19.5%) and those who had less contact with animals (21.7%) had significantly positive serology when compared with individuals from rural areas (9.4%) and those who had close contact with animals (13.2%). The overall picture is individuals of more specialized occupations had more frequently (25.9%) anti listeria antibodies similar to the results observed in developed countries where listeriosis is a public health problem in urban areas.

[Comparison of two neutralization tests, used in vesiculovirus Piry serodiagnosis]. / Comparação de dois testes de neutralização, utilizados no diagnóstico sorológico do vesiculovírus Piry.

A serological survey of Piry was undertaken of the sera of inhabitants of Catolância-Bahia State, Brazil. Serum results obtained by a vesiculovirus neutralization test of C6/36 cells read by ELISA are compared with those obtained by the classic technique, carried out on newborn mice. The agreement between the results was as high as 98.7% of the 204 sera tested and the neutralization test of C6/36 cells was chosen as the most suitable technique for the sero-survey testing.

[Strongyloidiasis in patients with pemphigus foliaceus]. / Estrongiloidíase em pacientes com pênfigo foliáceo.

In 30 patients with foliaceus pemphigus the frequency of strongyloidiasis was 40%, by three Baermann-Moraes examination. In the "Hospital do Pênfigo", for patients with pemphigus of Uberaba, the frequencies of strongyloidiasis in the employees (n = 14) and students (n = 47), of the annexed nursery, also were high, respectively 35.7% and 23.4%. In 7(58.3) of 12 samples from the soil of the hospital courtyard were found free-life forms of Strongyloides. The environmental factor and the susceptibility of the patients were associated with the high transmission of the strongyloidiasis.