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Biomedical subjects

N Katz

Publications and source records attributed to N Katz.

At least 271 records · Page 15Linked to original sources
PubMedDate not supplied

Validity of selected clinical signs and symptoms in diagnosis of Schistosoma mansoni infection.

Sensitivity, specificity and positive predictive values of selected clinical signs and symptoms in the diagnosis of Schistosoma mansoni infection were evaluated in 403 individuals (69% of inhabitants over 1 year of age) in an endemic area in Brazil (Divino). Highest sensitivity (13%) was found for blood in stools. Specificity over 90% was found for blood in stools, palpable liver with normal consistency and palpable hardened liver at middle clavicular (MCL) or middle sternal lines (MSL). Hardened liver at MSL (83%) or MCL (75%), and blood in stools (78%) presented higher positive predictive values for S. mansoni infection, while palpable liver with normal consistency at MCL (45%) or MSL (48%) presented smaller values. Enlarged liver without specification of its consistency has been traditionally used as an indicator of the infection in areas where malaria or Kala-azar are not endemic. Our results demonstrate that the probability that a person with blood in stools or hardened palpable liver is infected is higher than among those with palpable liver with normal consistency.

Brazil↗
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A multivariate analysis of socio-demographic factors, water contact patterns and Schistosoma mansoni infection in an endemic area in Brazil.

Associations between socio-demographic factors, water contact patterns and Schistosoma mansoni infection were investigated in 506 individuals (87% of inhabitants over 1 year of age) in an endemic area in Brazil (Divino), aiming at determining priorities for public health measures to prevent the infection. Those who eliminated S. mansoni eggs (n = 198) were compared to those without eggs in the stools (n = 308). The following explanatory variables were considered: age, sex, color, previous treatment with schistosomicide, place of birth, quality of the houses, water supply for the household, distance from houses to stream, and frequency and reasons for water contact. Factors found to be independently associated with the infection were age (10-19 and > or = 20 yrs old), and water contact for agricultural activities, fishing, and swimming or bathing (Adjusted relative odds = 5.0, 2.4, 3.2, 2.1 and 2.0, respectively). This suggests the need for public health measures to prevent the infection, emphasizing water contact for leisure and agricultural activities in this endemic area.

Adolescent↗
PubMedDate not supplied

A municipal level approach to the management of schistosomiasis control in Peri-Peri, MG, Brazil.

A schistosomiasis control program was implemented between 1974/87 in Peri-Peri, MG (622 inhabitants). Molluscicide (niclosamide) was applied at three monthly intervals in water sources with Biomphalaria glabrata, and individuals eliminating Schistosoma mansoni eggs in the feces were treated annually with oxamniquine. From 1974 to 1983 the control measures were undertaken by staff of the "René Rachou" Research Center FIOCRUZ (CPqRR), and from 1984 to 1987 these measures were included in the Capim Branco basic health network activities. During both periods, the prevalence, incidence, intensity of infection and hepatosplenic form as well as the number of infected snails decreased significantly. The prevalence decreased from 43.5 to 4.4%, the incidence from 19.0 to 2.9%, the overall intensity of S. mansoni from 281 to 87 and of the hepatosplenic form from 5.9 to 0.0%. The results obtained suggest that the municipal management of control measures was as effective as the vertical program conducted by CPqRR staff.

Adolescent↗
PubMedDate not supplied

Stool examination and rectal biopsy in the diagnosis and evaluation of therapy of schistosomiasis mansoni.

From each of a group of 217 adult males selected through enzyme-immunoassay or skin-test (Group A), six stool samples were examined by both the Lutz/Hoffman, Pons & Janer (Lutz/HPJ) and Kato/Katz methods. In addition, one oogram of the rectal mucosa was performed. By these methods, schistosomiasis was detected in 44.7%, 47.5% and 40.1% of the individuals respectively. To evaluate the methods in the assessment of cure, the last 40 patients from group A, treated with a single oral dose of oxamniquine at 15 mg/kg were followed up for six months (Group B). The criteria for parasitological cure included three stool examinations by Kato/Katz and Lutz/HPJ methods, one, three and six months post-treatment and a rectal biopsy between the fourth and sixth months post-treatment. The examinations were negative in 87.5%, 90% and 95% of the patients, respectively. The efficacy of oxamniquine was 82.5% when the three methods were considered together and there was no statistically significant difference between the sensitivity of the individual methods.

Adolescent↗
PubMedDate not supplied

Characterization of the non-apparent clinical form in the initial phase of schistosomiasis mansoni.

In this paper the history of 115 recruits that had bathed simultaneously in streams contaminated with Schistosoma mansoni, during military maneuvers, is reported. Thirty four of the infected patients presented the initial phase of the infection diagnosed through epidemiologic, clinical and laboratory parameters. Three out of the 34 patients did not reveal the clinical picture of the infection, thus being considered representatives of the non-apparent form of the disease. Differences between the intensity of blood eosinophilia, the area of immediate cutaneous reaction and the number of Schistosoma eggs eliminated in the stools proved not to be statistically significant (p > 0.05) when the non-apparent and acute cases of schistosomiasis were compared. These cases actually may be considered evidences of the non-apparent form hitherto merely taken for granted in the literature.

Adolescent↗
PubMedDate not supplied

[Preliminary trials of Guaiacum officinale L. as a molluscicide].

Aqueous suspensions of fruit's pericarp, leaves, root's bark and seeds of Guaiacum officinale were tested at different concentrations as molluscicide, cercaricide and piscicide. In the laboratory the suspension of fruit's pericarp produced 100% mortality for egg masses of B. glabrata at 100 ppm, for adult snails of Biomphalaria glabrata, B. straminea and B. tenagophila at 20 ppm, for Lebistes reticulatus (fishes) at 5 ppm and Schistosoma mansoni's cercariae at 1 ppm. The ethanolic extract of fruit's pericarp was not active against adult snails of B. glabrata. The lethal dose for adult snails(DL90) of the aqueous suspension of fruit's pericarp after 24 hours exposure, were: 15 ppm for B. glabrata; 14 ppm for B. straminea and 18 ppm for B. tenagophila. The DL90 of aqueous suspensions of root's bark, seeds and leaves were 57 ppm, 33 ppm and 15 ppm, respectively. In the field, B. glabrata adult snail mortality was 68% at 20 ppm and 100% at 40 ppm, when using suspension of fruit's pericarp.

Animals↗
PubMedDate not supplied

Identification of factors and groups at risk of infection with Schistosoma mansoni: a strategy for the implementation of control measures?

A fourteen year schistosomiasis control program in Peri-Peri (Capim Branco, MG) reduced prevalence from 43.5 to 4.4%; incidence from 19.0 to 2.9%, the geometric mean of the number of eggs from 281 to 87 and the level of the hepatoesplenic form cases from 5.9 to 0.0%. In 1991, three years after the interruption of the program, the prevalence had risen to 19.6%. The district consists of Barbosa (a rural area) and Peri-Peri itself (an urban area). In 1991, the prevalence in the two areas was 28.4% and 16.0% respectively. A multivariate analysis of risk factors for schistosomiasis indicated the domestic agricultural activity with population attributive risk (PAR) of 29.82%, the distance (< 10m) from home to water source (PAR = 25.93%) and weekly fishing (PAR = 17.21%) as being responsible for infections in the rural area. The recommended control measures for this area are non-manual irrigation and removal of homes to more than ten meters from irrigation ditches. In the urban area, it was observed that swimming at weekly intervals (PAR = 20.71%), daily domestic agricultural activity (PAR = 4.07%) and the absence of drinking water in the home (PAR = 4.29%) were responsible for infections. Thus, in the urban area the recommended control measures are the substitution of manual irrigation with an irrigation method that avoids contact with water, the creation of leisure options of the population and the provision of a domestic water supply.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Pulmonary manifestations in the initial phase of schistosomiasis mansoni.

The clinical and radiological pulmonary manifestations in the initial phase of schistosomiasis mansoni were studied in thirty previously healthy individuals who were simultaneously infected. The findings were compared with those concerning a control group and related to possible pathogenetic factors. The respiratory manifestations were of light or of moderate intensity, the dry cough being the most common symptom. The significant radiological alterations were: thickening of bronchial walls and beaded micronodulation, predominantly localized in the lower pulmonary fields. It was observed significant association between wheezing and IgE levels, estimated by the area of immediate intradermal reaction, as well as between the number of blood eosinophils and the occurrence of radiological changes. Moreover, there was correlation between the worm burden and the presence of wheezing, thoracic pain and beaded micronodulation. Thus, the clinical and radiological pulmonary manifestations described are significant part of the initial phase of schistosomiasis mansoni and present the worm burden, eosinophilia and levels of IgE as probable pathogenetic factors.

Adolescent↗
PubMedDate not supplied

Questionnaires in the screening for Schistosoma mansoni infection: a study of socio demographic and water contact variables in four communities in Brazil.

The use of questionnaires has been recommended for identifying, at a lower cost, individuals at risk for schistosomiasis. In this study, validity of information obtained by questionnaire in the screening for Schistosoma mansoni infection was assessed in four communities in the State of Minas Gerais, Brazil. Explanatory variables were water contact activities, sociodemographic characteristics and previous treatment for schistosomiasis. From 677, 1474, 766 and 3290 individuals eligible for stool examination in the communities, 89 to 97% participated in the study. The estimated probability of individuals to be infected, if they have all characteristics identified as independently associated with S.mansoni infection, varied from 15% in Canabrava, to 42% in Belo Horizonte, 48% in Comercinho and 80% in São José do Acácio. Our results do not support the hypothesis that a same questionnaire on risk factors could be used in screening for S.mansoni infection in different communities.

Adolescent↗
PubMedDate not supplied

Re-evaluation of schistosomiasis mansoni in Minas Gerais, Brazil. III. "Noroeste de Minas" mesoregion.

This study was conducted to assess the presence of schistosomiasis mansoni in the "Noroeste de Minas" mesoregion, an area considered non-endemic. A malacologic survey and parasitologic stool examinations were undertaken in 13 municipalities of the mesoregion. A sample of 3,283 primary school students was submitted to fecal examination by the Kato-Katz method. A total of 3,627 planorbids was collected and examined. The molluscs were identified as Biomphalaria straminea in seven municipalities (Unaí, Bonfinópolis de Minas, Paracatu, Jaão Pinheiro, Vazante, Lagamar and Lagoa Grande) and as Biomphalaria peregrina in one (Presidente Olegário). All planorbids were negative for Schistosoma mansoni. Four students were diagnosed with schistosomiasis in the municipalities of Buritis, Formoso, Paracatu and Unaí, but none of these cases was considered autochthonous. The data obtained indicate that the "Noroeste de Minas" mesoregion continues to be non-endemic for schistosomiasis mansoni, although the presence of intermediate hosts associated with parasitized individuals emphasizes the need for epidemiological surveillance of schistosomiasis in this mesoregion.

Adolescent↗
PubMedDate not supplied

Rate of action of schistosomicides in mice infected with Schistosoma mansoni.

Mice infected with adult Schistosoma mansoni were dosed with a single oral dose of 125 or 250 mg/kg oltipraz, 50 or 100 mg/kg oxamniquine, or 200 or 400 mg/kg praziquantel. The mortality rate of worms and oogram changes were determined between 1 and 16 weeks after dosing. The time required between dosing and postmortem to obtain maximum effectiveness was 1 week for praziquantel, 2 weeks for oxamniquine and 8 weeks for oltipraz. Changes in oograms persisted throughout most of the experiment, although relapse has been observed at the 4th week on.

Animals↗
PubMedDate not supplied

[Molluscacide and cercariacide activity of different species of Eucalyptus].

Hydrolates and essential oils of several Eucalyptus species were tested on adult snails and egg masses of Biomphalaria glabrata, and cercaria of Schistosoma mansoni. These products were obtained by vapor dragging. Eight out of 21 hydrolates presented activity on snails, nine on egg masses and three on cercaria at 1:4 dilutions. Eleven oils were active on both snails and egg masses at 20 ppm concentrations. The hydrolate of E. deanei was active both on snails, egg masses and cercaria at 1:4 dilution and its essential oil at 20 ppm.

Animals↗