Ageing with Trypanosoma cruzi infection in a community where the transmission has been interrupted: the Bambuí Health and Ageing Study (BHAS).

BACKGROUND: The prevalence of Chagas' disease is decreasing in Brazil. Due to cohort effect, the disease might remain a public health problem for some time among older individuals. The present burden of Trypanosoma cruzi infection for the elderly living in areas where the transmission has been interrupted has not been studied. METHODS: The prevalence of T. cruzi infection and its association with indicators of health status and health services use were assessed among the elderly living in one of the oldest endemic areas in Brazil (Bambuí, MG). Seropositivity was determined by blood tests (IHA and ELISA) performed in 85.6% of all residents aged 60+ (1496/1742) and in 83.1% of sampled residents aged 5-59 years (1212/1458). RESULTS: Seropositivity showed a cohort effect, with no cases below 20 years and high prevalence among those aged 60+ years (37.7%). After adjustment for confounders, seropositivity was associated with self-rated health reasonable (OR = 1.43; 95% CI : 1.03-1.98) and bad/very bad (OR = 1.89; 95% CI : 1.30-2.75), staying in bed in past 2 weeks (OR = 1.88; 95% CI : 1.21-2.92), hospitalization in past 12 months (OR = 1.41; 95% CI : 1.05-1.89) and use of 5+ prescribed medications in past 3 months (OR = 1.75; 95% CI : 1.15-2.59). IMPLICATIONS: Our results are an example of how survival of individuals with past exposure to infectious disease may lead to a different picture of ageing in the developing world. Policy makers need to consider the extra burden imposed by increasing rates of non-infectious disease among the elderly (as observed in Brazil) including the consequences of T. cruzi infection in areas where the infection was widespread in the past.

The control of schistosomiasis in Brazil: an ethnoepidemiological study of the effectiveness of a community mobilization program for health education.

This study combined anthropological and epidemiological approaches to assess the effectiveness of community mobilization for health education, developed as part of the Brazilian program for the control of schistosomiasis. The study was carried out in two villages in the state of Minas Gerais, SE Brazil, exposed to the same established schistosomiaisis control strategies. Residents of one village were also exposed to the community mobilization for health education (study area) while those from the other community were not exposed to this program (control area). Schistosoma mansoni prevalence rates for the study and control villages were compared over time. A population-based survey was carried out in the two villages to obtain information on socio-demographic factors, water contact patterns and knowledge of S. mansoni transmission. Intensive ethnographic interviews with key informants in each locality were employed to determine the knowledge, attitudes and practices of the communities regarding schistosomiasis. Ethnographic data were analysed using the model of systems of signs, meanings and actions. Differences were observed in prevalence trends between the study and control areas but they could not be explained by the existence of the community mobilization program in the former. It was also found that educational actions carried out by the Brazilian Ministry of Health transmitted information on schistosomiasis but were ineffective in transforming the information received into preventive behaviour related to water contact. With regard to disease, the population studied tended to distinguish minor symptoms, which they associated with water contact, from major symptoms, which they attributed to lack of medical treatment. This distinction mediated perceptions of the severity of "xistose" and reduced the importance of avoiding contact with potentially infested waters. The perception of protection conferred by treatment observed in the present study might also apply to other communities where access to treatment is readily available and free. The extent to which this perception exists in endemic areas needs to be determined so that apparent contradictions of this type can be addressed in future educational programs.

American cutaneous leishmaniasis: use of a skin test as a predictor of relapse after treatment.

While relapses following clinical cure of American cutaneous leishmaniasis are frequent, no test has been described until now to predict such relapses. A cohort of 318 American cutaneous leishmaniasis patients was followed up for two years after treatment with meglumine antimoniate, during which time 32 relapses occurred, 30 in the first year and two in the second (accumulated risk: 10.5%). No association was found between these relapses and the parasite-specific antibody response before and after treatment, or between the relapses and stratification by sociodemographic and clinical characteristics. However when Leishmania was used as antigen, patients with a negative skin test at the time of diagnosis presented a 3.4-fold higher risk (hazard risk = 3.4; 95% confidence interval, 1.7-7.0) of American cutaneous leishmaniasis relapse, compared with patients with a positive response. This result shows that the skin test can be a predictor of American cutaneous leishmaniasis relapse after treatment.

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.

[Effectiveness of the yellow fever vaccine 17D: an epidemiologic evaluation in health services]. / Efetividade da vacina antiamarílica 17D: uma avaliação epidemiológica em serviços de saúde.

The purpose of this study was to evaluate the efficacy of the 17D yellow fever vaccine in the conditions under which it is used in public health services. In 1989, a nonconcurrent prospective study was carried out in Bocaiúva, Minas Gerais State, Brazil, 6 months after mass vaccination of the population. The study population was made up of first-grade students from all the schools in Bocaiúva. The exposed group consisted of a simple random sample of vaccinated students (n = 173) and the unexposed group consisted of all those who had not been vaccinated (n = 55). Serum samples were examined with the neutralization test in mice; these tests were conducted blind, that is, the examiner did not know the vaccination status of the subject. The serology results were as follows: of those vaccinated, 75% were seropositive, 17% were seronegative, and 7% showed an inconclusive result; in the unvaccinated children, these results were 9%, 87%, and 4%, respectively. The age-adjusted seropositivity ratio between vaccinated and unvaccinated children was 7.6 (95% CI: 3.4 to 16.7). The proportion of seropositivity attributable to vaccination, adjusted for age, was 86.8% (95% CI: 70.6 to 94.0). The results showed that the efficacy of the vaccine, defined by means of seropositivity for the virus, was below the levels expected for the 17D vaccine. This may have been due to operational failures in the conservation or application of the vaccine. The results point to the need for routine systematic evaluations by the health services after mass utilization of the vaccine.

[Evaluation of a program for the control of schistosomiasis in municipalities located on the basin of the Sao Francisco River, Minas Gerais, Brazil]. / Avaliação do programa de controle da esquistossomose (pce/pcden) em municípios situados na Bacia do Rio São Francisco, Minas Gerais, Brasil.

An evaluation of the control program on schistosomiasis (PCE/PCDEN) was performed in the region of São Francisco river in MInas Gerais. The study area comprises six municipalities, with 130,000 inhabitants and 916 localities situated in an area with 10,722 km2. The activities initiated in 1983-85 in four municipalities and in 1987 in the other two. The main measures of control were repeated treatment with oxamniquine and use of niclosamide. The prevalence of infection by Schistosoma mansoni in the first four municipalities, that was initially around 18 and 32%, dropped abruptly after the first intervention (1983/85) and remained in levels below the initial ones until the last assessment (1990-94); similar trends were observed for the proportion of infected snails. In these municipalities, the proportion of localities without infection or with prevalence below 5% increased in relation to those with higher prevalence. In the other two municipalities, with initial prevalence below 5%, there were no substantial changes in S. mansoni prevalence or proportion of infected snails; the cost benefit of the program in these municipalities need to be assessed and the priorities redirected to eradicate focal areas and prevent spread to non infected localities. The authors call attention to the difficulties in the long term of a control program based on repeated treatments. Information on factors associated with S. mansoni infection in each locality, or in groups of similar localities, would allow to develop additional measures to treatment that could last longer and be less dependent on the continuous use of chemotherapy.

Effect of skin colour and selected physical characteristics on Schistosoma mansoni dependent morbidity

O efeito da cor da morbidade associada ao Schistosoma mansoni foi estudado em duas areas endemicas situadas no Estado de Minas Gerais, Brasil. Dos 2773 habitantes elegiveis, 1971 (71,1 por cento) participaram do estudo: 545 (27,6 por cento) foram classificados como brancos, 719 (36,5 por cento) como intermediarios e 707 (35,9 por cento) como negros. Os sinais e sintomas dos individuos que eliminavam ovos de S. mansoni nas fezes (casos) foram comparados aos daqueles que nao apresentavam ovos do parasita neste exame (controles). As razoes de chance foram ajustadas por idade, genero, tratamento anterior para a esquistossomose, area endemica e qualidade do domicilio. Nao houve evidencia de um efeito modificador da cor para a ocorrencia de diarreia, sangue nas fezes ou dor abdominal. Um efeito modificador da cor foi evidente entre aqueles com maiores contagens de ovos nas fezes (>=400opg), no que se refere a hepatomegalia: as razoes de chance foram menores entre individuos classificados como negros (5,4 e 6,5 para presenca de figado palpavel nas linhas hemiclavicular e metodo esternal, respectivamente) e maiores entre aqueles classificados como brancos...

Effect of skin colour and selected physical characteristics on Schistosoma mansoni dependent morbidity.

The effect of the colour group on the morbidity due to Schistosoma mansoni was examined in two endemic areas situated in the State of Minas Gerais, Brazil. Of the 2773 eligible inhabitants, 1971 (71.1%) participated in the study: 545 (27.6%) were classified as white, 719 (36.5%) as intermediate and 707 (35.9%) as black. For each colour group, signs and symptoms of individuals who eliminated S.mansoni eggs (cases) were compared to those who did not present eggs in the faeces (controls). The odds ratios were adjusted by age, gender, previous treatment for schistosomiasis, endemic area and quality of the household. There was no evidence of a modifier effect of colour on diarrhea, bloody faeces or abdominal pain. A modifier effect of colour on hepatomegaly was evident among those heaviest infected (> or = 400 epg): the adjusted odds ratios for palpable liver at the middle clavicular and the middle sternal lines were smaller among blacks (5.4 and 6.5, respectively) and higher among whites (10.6 and 12.9) and intermediates (10.4 and 10.1, respectively). These results point out the existence of some degree of protection against hepatomegaly among blacks heaviest infected in the studied areas.

A 13-year follow-up of treatment and snail control in an area endemic for Schistosoma mansoni in Brazil: incidence of infection and reinfection.

The incidences of Schistosoma mansoni infection and reinfection were investigated in an endemic area of Brazil (Peri-Peri, State of Minas Gerais) where chemotherapy and snail control had been used for 13 years (1974-87). Two cohorts were followed: the first consisted of 584 individuals with no evidence of infection at entry (infection cohort), and the second comprised 296 individuals who were treated and did not eliminate eggs 8-12 months afterwards (reinfection cohort). The incidence of infection (per 100 person-years) decreased from 7.5 in 1974-77 to 3.6 in 1986-87, and that of reinfection from 21.3 in 1974-77 to 3.7 in 1986-87. Calendar period, age at risk, and sex were independently associated with both infection and reinfection, while a heavy S. mansoni egg count prior to treatment (> or = 500 epg (eggs per gram of stools)) was independently associated with reinfection. The geometric mean number of eggs after treatment among those reinfected (47 epg) was approximately half that among those infected for the first time (81.5 epg). Age at risk had the greatest effect on both infection and reinfection. The rate ratios of infection and reinfection were 3 to 6 times higher among individuals younger than 20 years than among those aged > or = 25 years, even after adjusting for confounders. This suggests the existence of a strong protective effect with increased age (because of biological and/or environmental factors) for both infection and reinfection.

PIP: Between 1974 and 1987 in Peri-Peri, Capim Branco Municipality, Minas Gerais State in Brazil, the schistosomiasis control program conducted a snail surveillance every 2-6 months, collected stool samples from village members annually, and administered oxamniquine to every person with Schistosoma mansoni eggs in their stool. Incidence of S. mansoni infection and reinfection steadily fell (from 7.5 to 3.6/100 person-years and from 21.3 to 3.7/100 person-years, respectively; p .001). Males were more likely to be infected or become reinfected than females (9.3 vs. 4.8, p .001 and 12.3 vs. 8, p = .025, respectively). 5-9 and 10-14 year olds had the highest incidence of S. mansoni reinfection (24.2 and 21.2 vs. 15.3 for 15-19 year olds, p .001, respectively). Infection rates were highest in 10-14 and 15-19 year olds (15 and 13.8 vs. 3.1-10.1 for 0-4 and 5-9 year olds, p .001, respectively). Reduced water contact and/or increased resistance/immunity may have accounted for lower infection and reinfection rates in people older than 20 years old. Infected people whose stool had a least 500 S. mansoni eggs/gm (epg) of stools were more likely to become reinfected faster and more frequently than people who had less than 500 epg (rate ratio, 1.7; p .001). Mean number of eggs was lower in the reinfected cohort than in the infected cohort (47 vs. 81.5 [ranges, 12-1320 vs. 12-5544]; p .001), suggesting that treatment protected against heavy reinfections. People whose egg count was at least 500 epg before treatment and were at least 25 years old did not become reinfected at a greater rate, however, further supporting the protective effect of age. These results showed that calendar period, age at risk, and sex were each associated with infection and reinfection and that a heavy egg count before treatment was independently associated only with reinfection.

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.

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

Foi examinada a sensibilidade, a especificidade e os valores preditivos positivos de alguns sinais e sintomas para o diagnostico presumivel da infeccao pelo Schistosoma mansoni em uma area edemica de Minas Gerais (Divino): 403 individuos (69 por cento dos habitantes com mais de 1 ano de idade) participaram da investigacao. Maior sensibilidade foi observada para sangue nas fezes (13 por cento). Especificidades acima de 90 por cento foram encontradas para sangue nas fezes, e para figado palpavel com consistencia normal ou aumentada nas linhas hemi-clavicular (LHC) e medio-esternal (LME). Os maiores valores preditivos positivos para a infeccao foram observados para figado palpavel com consistencia aumentada na LME (83 por cento) ou LHC (75 por cento) e presenca de sangue nas fezes (78 por cento); os menores valores foram para figado palpavel com consistencia normal na LME (48 por cento) e LHC (45 por cento). A presenca de figado palpavel sem especificacao da sua consistencia tem sido tradicionalmente utilizada como um indicador da infeccao em areas onde a malaria ou o Kalazar nao sao endemicos. Nossos resultados mostram que a probabilidade de individuos com sangue nas fezes ou com aumento da consistencia do figado apresentarem a infeccao e maior do que entre aqueles com figago palpavel mas com a consistencia normal.

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

Foi examinada a existencia de associacao entre fatores socio-demograficos, padroes de contatos com a agua e a infeccao pelo Schistosoma mansoni em uma area endemica em Minas Gerais (Divino), com o objetivo de determinar medidas prioritarias para prevenir a infeccao; 506 individuos (87 por cento dos habitantes com mais de 1 ano de idade) participaram do estudo. Aqueles que apresentavam ovos (n=198) foram comparados aos que nao apresentavam ovos de S. mansoni nas fezes (n=308). As seguintes variaveis exploratorias foram consideradas: idade, sexo, cor, tratamento anterior com esquistossomicida, local de nascimento, qualidade da habitacao, origem da agua para o domicilio, distancia do domicilio em relacao ao corrego, frequencia e motivos de contatos com agua. As variaveis que apresentaram associacoes independentes com a infeccao foram: idade (10-19 e * 20 anos), contato com aguas para trabalho agricola, pesca e natacao ou banho (Odds relativas ajustadas = 5.0, 2.4, 3.2, 2.1 e 2.0, respectivamente). Estes resultados sugerem que medidas para prevenir a infeccao devem priorizar os contatos com aguas para o trabalho e o lazer nesta area endemica.

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.

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.

Factors associated with AIDS and AIDS-like syndrome among homosexual and bisexual men in Minas Gerais, Brazil.

A case-control study to determine factors associated with AIDS and AIDS-like syndrome among homosexual/bisexual men was conducted in the State of Minas Gerais (Brazil). Eighty-three per cent (45 patients) of all AIDS/AIDS-like syndrome cases in homosexual/bisexual men reported in Minas Gerais between February, 1986 and June, 1987 were compared to 133 seronegative controls seen at the same clinic. Blood samples were tested by ELISA and confirmed by Western blot. Sex with men from the USA, sex with someone who developed AIDS, number of male partners (greater than or equal to 100 lifetime), age (greater than or equal to 30 years old) and ethnicity (white) were independently associated with AIDS/AIDS-like syndrome (Odds Ratios = 5.5, 4.3, 3.9, 3.5 and 2.7, respectively). Thirty-nine per cent of cases and 44% of controls reported bisexual activity during the previous two years. From these, a high proportion reported anal intercourse with women in the same period (53% of bisexual cases and 33% of bisexual controls). Bisexual men had more male partners than female partners in the previous two years (median male partners = 20 for cases and five for controls; median female partners = three for both cases and controls). This explains in part why the epidemic has increased more rapidly among men then among women in Minas Gerais, despite the large proportion of bisexuals with the disease.

PIP: A case control study to determine factors associated with AIDS and AIDS- like syndrome among homosexual/bisexual men was conducted in the state of Minas Gerais, Brazil. 83% (45 patients) of all AIDS/AIDS-like syndrome cases in this group of men reported in Minas Gerais between February 1986-June 1987 were compared to 133 seronegative controls seen at the same clinic. Blood samples were tested by ELISA and confirmed by western blot. Sex with men from the US, with someone who developed AIDS, number of male partners ( or = 100 lifetime), age ( or = 30 years old), and ethnicity (white) were independently associated with AIDS/AIDS-like syndrome (odds ratio=5.5, 4.3, 3.9, 3.5, and 2.7, respectively). 39% of cases and 44% of controls reported bisexual activity over the previous 2 years. From these, a high proportion reported anal intercourse with women in the same period (53% of bisexual cases and 33% of bisexual controls). Bisexual men had more male partners than female ones in the previous 2 years (median number=20 for cases and 5 for controls; median number of female partners=3 for both cases and controls). This explains in part why the epidemic has increased more rapidly among men than women in Minas Gerais, despite the large proportion of bisexuals with the disease.

Anthropometric measures in relation to Schistosomiasis mansoni and socioeconomic variables.

A cross-sectional study of anthropometric measures and their association with socioeconomic variables, infection by Schistosoma mansoni, intensity of infection and splenomegaly was carried out in an endemic area for schistosomiasis in Brazil (Comercinho), using multiple logistic regression methods. Eighty-seven per cent of all 1.5-14.4 year-old children in the area participated in the study. Children below the 5th percentile (USA Ten State Survey) for height-for-age, weight-for-age and arm muscle area-for-age were compared to those greater than the 5th percentile. There was no association between low anthropometric measures and schistosomiasis or socioeconomic variables in children under five years of age. For the 4.4-14.4 year-old children, poor condition of the heads of family and poorer housing were independently associated with low height and arm muscle area. Heavy excretion of S. mansoni eggs (greater than or equal to 500 epg) was related to low height, and splenomegaly was the variable which showed the strongest association with low height, weight and arm muscle area (odds ratios adjusted for socioeconomic variables were 6.4, 3.5 and 3.7 respectively). This indicates that there is a biological component for low anthropometric measures in the severe form of schistosomiasis and this reinforces the need for public health measures to prevent the development of splenomegalies in endemic areas.