A comparative cross-sectional study on the prevalence and morbidity of schistosomiasis in a community in northeastern Brazil (1979-2010)

A cross-sectional study on the prevalence and morbidity of schistosomiasis was conducted in the main settlement of the municipality of Alhandra, in the southern coastal region of the state of Paraíba, in 2010. The results of this study were compared with the results of a previous study conducted in the same area in 1979. The systematic sampling per family conglomerate included approximately 10% of the resident population in the urban area of Alhandra. Faecal examinations were performed using the Kato-Katz method. The clinical forms of the disease were classified in accordance with FS Barbosa as Type I - intestinal form, Type II - hepatointestinal form and Type III - hepatosplenic form. The prevalence of the infection in 2010 was 10.05%, whereas in 1979 it was 46.6% among untreated patients. The percentages of the three clinical forms in 2010 were as follows: 95.3% Type I, 4.6% Type II and 0% Type III; in 1979, the percentages were 94.4%, 3% and 2.6% for Types I, II and III, respectively. In 1979, 6.07% of the Biomphalaria glabrata specimens (the intermediate host in this area) excreted cercariae, where in 2010 only 1.27% of the specimens caught excreted the parasite.

A comparative cross-sectional study on the prevalence and morbidity of schistosomiasis in a community in northeastern Brazil (1979-2010).

A cross-sectional study on the prevalence and morbidity of schistosomiasis was conducted in the main settlement of the municipality of Alhandra, in the southern coastal region of the state of Paraíba, in 2010. The results of this study were compared with the results of a previous study conducted in the same area in 1979. The systematic sampling per family conglomerate included approximately 10% of the resident population in the urban area of Alhandra. Faecal examinations were performed using the Kato-Katz method. The clinical forms of the disease were classified in accordance with FS Barbosa as Type I - intestinal form, Type II - hepatointestinal form and Type III - hepatosplenic form. The prevalence of the infection in 2010 was 10.05%, whereas in 1979 it was 46.6% among untreated patients. The percentages of the three clinical forms in 2010 were as follows: 95.3% Type I, 4.6% Type II and 0% Type III; in 1979, the percentages were 94.4%, 3% and 2.6% for Types I, II and III, respectively. In 1979, 6.07% of the Biomphalaria glabrata specimens (the intermediate host in this area) excreted cercariae, where in 2010 only 1.27% of the specimens caught excreted the parasite.

Prevalence and Morbidity Data on Schistosoma mansoni Infection in Two Rural Areas of Jequitinhonha and Rio Doce Valleys in Minas Gerais, Brazil.

Objective. This study aimed to compare the prevalence and morbidity data on Schistosoma mansoni infection in two rural areas: the Jequitinhonha valley (area 1) and the Rio Doce valley (area 2) in the state of Minas Gerais, Brazil, covering the period from 2007 to 2010. Material and Methods. The parasitological stool tests were based on the quantitative method of Kato modified by Katz et al. Three clinical forms were considered: type I-schistosomiasis infection, type II-hepatointestinal form, and type III-hepatosplenic form. Results. The prevalence of infection among inhabitants of area 1 was 22.9%, with 2.1% presenting the hepatosplenic form and two cases of schistosomal myeloradiculopathy. The infection prevalence rate in area 2 was 20.2%, with 3.3% presenting the hepatosplenic form. Conclusion and Recommendation. There was no difference in the prevalence and in the morbidity of Schistosoma mansoni infection between the two areas, but it was predominant in young men with a low intensity of infection. The cases of schistosomal myeloradiculopathy in area 1 can be highlighted: these emphasize that schistosomiasis should not be neglected in Brazil. The lack of infection control in both areas may be related to the poor sanitation system, the absence of previous treatment, and the reinfection process.

Specific schistosomiasis treatment as a strategy for disease control.

The great hope for schistosomiasis treatment began with the development of oxamniquine and praziquantel. These drugs can be administered orally in a single dose and have a high curative power with minor side effects. In this study, we carried out a field experiment involving a population of 3,782 people. The population was examined at four localities in Minas Gerais within the valleys of the Doce and Jequitinhonha Rivers. In this cohort, there were 1,790 patients infected with Schistosoma mansoni (47.3%) and we showed that only 1,403 (78.4%) could be treated with oxamniquine in a single dose of 12.5-20 mg/kg orally. The other 387 (21.6%) were not treated during the first stage because of contraindications (pregnancy or impeditive diseases), absences or refusals. It was observed that, on average, 8.8-17% of the infected patients continued to excrete S. mansoni eggs at the end of the 2nd month after treatment and 30-32% of the cohort was infected by the end of the 24th month. In one of the areas that we followed-up for a total of 30 years, the prevalence of the infection with S. mansoni fell from 60.8-19.3% and the hepatosplenic form of the disease dropped from 5.8-1.3%. We conclude that specific treatment of schistosomiasis reduces the prevalence of infection in the short-term and the morbidity due to schistosomiasis in medium to long-term time frames, but does not help to control disease transmission.

Specific schistosomiasis treatment as a strategy for disease control

The great hope for schistosomiasis treatment began with the development of oxamniquine and praziquantel. These drugs can be administered orally in a single dose and have a high curative power with minor side effects. In this study, we carried out a field experiment involving a population of 3,782 people. The population was examined at four localities in Minas Gerais within the valleys of the Doce and Jequitinhonha Rivers. In this cohort, there were 1,790 patients infected with Schistosoma mansoni (47.3 percent) and we showed that only 1,403 (78.4 percent) could be treated with oxamniquine in a single dose of 12.5-20 mg/kg orally. The other 387 (21.6 percent) were not treated during the first stage because of contraindications (pregnancy or impeditive diseases), absences or refusals. It was observed that, on average, 8.8-17 percent of the infected patients continued to excrete S. mansoni eggs at the end of the 2nd month after treatment and 30-32 percent of the cohort was infected by the end of the 24th month. In one of the areas that we followed-up for a total of 30 years, the prevalence of the infection with S. mansoni fell from 60.8-19.3 percent and the hepatosplenic form of the disease dropped from 5.8-1.3 percent. We conclude that specific treatment of schistosomiasis reduces the prevalence of infection in the short-term and the morbidity due to schistosomiasis in medium to long-term time frames, but does not help to control disease transmission.

Schistosomiasis haematobia: histopathological course determined by cystoscopy in a patient in whom praziquantel treatment failed.

Schistosomiasis haematobia or urinary schistosomiasis is one of the main public health problems in Africa and the Middle East. A single dose of 40 mg praziquantel per kg body weight continues to be the treatment of choice for this infection. The aims of this follow-up were to study the post-treatment course of a patient infected with S. haematobium and not submitted to re-exposure, and to identify complications of the disease and/or therapeutic failure after praziquantel treatment by histopathological analysis. Treatments were repeated under medical supervision to ensure the correct use of the drug. In view of the suspicion of lesions in cystoscopy, the patient was submitted to bladder biopsy. The histopathological characteristics observed in biopsies obtained, after each treatment, indicated viability of parasite eggs and activity of granulomas.

Schistosomiasis haematobia: histopathological course determined by cystoscopy in a patient in whom praziquantel treatment failed / Esquistossomíase hematóbica: seguimento histopatológico determinado por cistoscopia em um paciente com falha terapêutica ao praziquantel

Schistosomiasis haematobia or urinary schistosomiasis is one of the main public health problems in Africa and the Middle East. A single dose of 40 mg praziquantel per kg body weight continues to be the treatment of choice for this infection. The aims of this follow-up were to study the post-treatment course of a patient infected with S. haematobium and not submitted to re-exposure, and to identify complications of the disease and/or therapeutic failure after praziquantel treatment by histopathological analysis. Treatments were repeated under medical supervision to ensure the correct use of the drug. In view of the suspicion of lesions in cystoscopy, the patient was submitted to bladder biopsy. The histopathological characteristics observed in biopsies obtained, after each treatment, indicated viability of parasite eggs and activity of granulomas.

A Esquistossomíase Hematóbica ou Esquistossomíase Urinária é um dos principais problemas de Saúde Pública na África e no Oriente Médio. Uma única dose de praziquantel 40 mg/kg de peso, continua sendo o tratamento de escolha para esta infecção. Os objetivos deste seguimento foram: avaliar o período pós-tratamento de um paciente infectado com Schistosoma haematobium e não submetido à re-exposição e, identificar as complicações da doença e/ou falha terapêutica, após o tratamento com praziquantel, por análise histopatológica de material obtido por biópsia vesical. O tratamento foi repetido sob supervisão médica para assegurar o uso correto do medicamento. Na presença de lesões suspeitas a cistoscopia, o paciente foi submetido a biópsia vesical. As características histopatológicas observadas nos materiais obtidos por biópsia, após cada tratamento, indicaram viabilidade de ovos e atividade dos granulomas.

Human study and experimental behavior of Schistosoma mansoni isolates from patients with different clinical forms of schistosomiasis.

Twenty Schistosoma mansoni strains were isolated from three groups of patients (intestinal, hepatointestinal and hepatosplenic clinical forms) born and living in the town of Capitão Andrade, Minas Gerais, Brazil. Schistosomal isolate from each group was inoculated into three sets of mice with 25, 50 and 100 cercariae. The animals were killed 90 and 180 days after infection and submitted to extensive histopathological study of the liver, lung, intestine and spleen to determine qualitative and quantitative morphological characteristics, mainly of the granulomas. The histopathological changes caused the same patterns of infection in mice and were proportional to the inoculum and the time of infection, confirming the relevance of quantitative aspects in the determination of the disease. These data indicate three possibilities: (1) mouse model is not adequate to predict possible differences in the S. mansoni isolates obtained from patients; (2) field isolates are probably genetic polymorphic and undifferentiated; (3) schistosomiasis in human does not depend on parasite intrinsic factors, but on multivariable factors, such as intensity and duration of infection, time of infection, age and gender and other characteristics such as host response.

A thirty years follow-up study on Schistosomiasis mansoni in a community of Minas Gerais, Brazil

During thirty years - 1973-2003 - a group of individuals infected by Schistosoma mansoni in Capitão Andrade, Rio Doce Valley, Minas Gerais, Brazil, was evaluated by the same authors, being one of the longest follow-up studies on schistosomiasisis mansoni in an endemic area. The diagnosis of S. mansoni was based on parasitological stool tests. In the clinical classification, three groups were considered: type I - schistosomiasis-infection, type II - hepatointestinal form, and type III- hepatosplenic form. The prevalence of infection were 60.8 percent in 1973, 36.2 percent in 1984, 27.3 percent in 1994, and 19.4 percent in 2003, while the index of hepatosplenomegaly were respectively 5.8 percent, 2.8 percent, 2.3 percent and 1.3 percent. The maintenance of high prevalence and severity of clinical forms are probably related to reinfection.

A thirty years follow-up study on Schistosomiasis mansoni in a community of Minas Gerais, Brazil.

During thirty years - 1973-2003 - a group of individuals infected by Schistosoma mansoni in Capitão Andrade, Rio Doce Valley, Minas Gerais, Brazil, was evaluated by the same authors, being one of the longest follow-up studies on schistosomiasisis mansoni in an endemic area. The diagnosis of S. mansoni was based on parasitological stool tests. In the clinical classification, three groups were considered: type I - schistosomiasis-infection, type II - hepatointestinal form, and type III- hepatosplenic form. The prevalence of infection were 60.8% in 1973, 36.2% in 1984, 27.3% in 1994, and 19.4% in 2003, while the index of hepatosplenomegaly were respectively 5.8%, 2.8%, 2.3% and 1.3%. The maintenance of high prevalence and severity of clinical forms are probably related to reinfection.

Clinical and laboratorial evaluation of urinary schistosomiasis in Brazilians after staying in Mozambique.

We examined 87 Brazilian individuals of a group of 132 that, on July and November 1994, participated in a peace mission in Mozambique. They served in an endemic area for haematobic schistosomiasis, where they swam in Licungo river during leisure time. Their arithmetic mean age was 31 year and all of them were male. Their urine test showed that 30 (34.5%) eliminated S. haematobium eggs and 55 (63.2%) presented positive serology by the enzyme-linked immunoelectrotransfer blot test with purified microsomal antigen of S. haematobium adult worms. Eosinophilia was found in 30 (34.5%), haematuria in 26 (29.9%), dysuria in 32 (36.8%) and lumbar pain in 36 (41.4%). All of those that eliminated eggs through urine had positive serology. Among the 25 patients with positive serology and without S. haematobium eggs in the urine test, 13 were symptomatic and 12 asymptomatic. The treatment with praziquantel for the 30 patients, with urine positive to S. haematobium eggs, presented 70% of parasitological cure.

Clinical and laboratorial evaluation of urinary schistosomiasis in Brazilians after staying in Mozambique

Nós examinamos 87 brasileiros de um grupo de 132 que, entre julho e novembro de 1994, participaram de um missão de paz em Moçambique. Eles serviram em uma área endêmica de esquistossomose haematóbica e nadaram no rio Licungo em períodos de lazer. A idade aritmética deles era 31 anos e todos eram do gênero masculino. O exame de urina revelou que 30 (34,5%) eliminavam ovos de S. haematobium e 55 (63,2%) tinham sorologia positiva pelo teste enzyme-linked immunoelectrotransfer blot com antígeno microsomal purificado de vermes adultos de S. haematobium. Eosinofilia foi encontrada em 30 (34,5%), haematuria em 26(29,9%), disúria em 32(36,8%) e dor lombar em 36(41,4%). Todos que eliminavam ovos pela urina tiveram sorologia positiva. Entre os 25 pacientes com sorologia positiva e sem ovos de S. haematobium no exame de urina, 13 eram sintomáticos e 12 assintomáticos. O tratamento pelo Prazinquantel nos 30 pacientes com urina positiva para ovos de S. haematobium apresentou 70% de cura parasitológica.

Cystoscopy in the diagnosis and follow-up of urinary schistosomiasis in Brazilian soldiers returning from Mozambique, Africa.

The assessment of urinary schistosomiasis in individuals coming from endemic areas often requires diagnostic resources not used in areas of exposure in order to determine complications or to establish more precise criteria of cure. Cystoscopy and 24-hour urine examination were performed, after treatments with praziquantel 40 mg/kg body weight, single dose, on 25 Brazilian military men who were part of a United Nations peace mission to Mozambique in 1994. The median age of the individuals was 29 years and all presented a positive urine parasitological exam. The alterations detected by cystoscopy were hyperemia and granulomas in the vesical submucosa in 59.1% of the individuals and only granulomas in 40.9%. A vesical biopsy revealed granulomas in all patients and viable eggs in 77.3% even after a period during which the patients no longer excreted eggs in urine. Cystoscopy after treatment, followed by biopsy and histopathological evaluation, performed in areas where the evolution of the disease can be better monitored, was found to be a safe criterion of parasitological cure.

Cystoscopy in the diagnosis and follow-up of urinary schistosomiasis in Brazilian soldiers returning from Mozambique, Africa

A avaliação de esquistossomose urinária em indivíduos procedentes de áreas endêmicas, freqüentemente requer recursos diagnósticos não usados nas áreas de exposição, para determinar as complicações ou estabelecer um critério de cura mais preciso. A cistoscopia e o exame de urina de 24 horas foram realizados, após tratamentos com praziquantel na dose de 40 mg/kg de peso, dose única, em 25 militares brasileiros que participaram de uma Missão de Paz pela ONU em Moçambique no ano de 1994. A idade média dos indivíduos foi de 29 anos e todos apresentavam exame parasitológico de urina positivo. As alterações detectadas pela cistoscopia foram hiperemia e granulomas na submucosa vesical em 59.1% dos indivíduos e somente granulomas em 40.9%. A biópsia vesical revelou granulomas em todos os pacientes e ovos viáveis em 77.3%, mesmo após um período durante o qual os pacientes não mais eliminavam ovos pela urina. Após o tratamento, a cistoscopia seguida por biópsia e avaliação histopatológica, realizada em áreas onde a evolução da doença pode ser monitorada melhor, demonstrou ser um critério mais seguro de cura parasitológica.

Therapeutic failure of praziquantel in the treatment of Schistosoma haematobium infection in Brazilians returning from Africa.

Several cases of therapeutic failure of praziquantel used for the treatment of urinary schistosomiasis have been reported. Alternative drugs, like niridazol and metrifonate, have shown a lower therapeutic effect and more side effects than praziquantel. Twenty-six Brazilian military men (median age of 29 years) with a positive urine parasitological exam who were part of a United Nation peace mission in Mozambique in 1994 were treated with 40 mg/kg body weight praziquantel, single dose. They swam in Licungo river (Mocuba city, Mozambique) during the weekends. After this, they presented haematuria, dysuria, polakiuria, and lumbar pain. Control cystoscopy examinations carried out between 6 and 24 months after each treatment (including two additional treatments at a minimum interval of 6 months) revealed the presence of viable eggs. Granulomas in the vesical submucosa were observed in 46.2% (12/26) of the individuals. A vesical biopsy confirmed the presence of granulomas in all of these patients and the presence of viable eggs in 34.3% (9/26) of individuals who no longer excreted eggs in urine. The eggs filled with miracidia showed characteristics of viability. Histopathological examination using different strains demonstrated therapeutic failure and the need for repeated treatment. In this study, we demonstrated a low efficacy of praziquantel in the treatment of schistosomiasis haematobia, and the necessity of the urinary bladder biopsy as criterion of cure.

Therapeutic failure of praziquantel in the treatment of Schistosoma haematobium infection in Brazilians returning from Africa

Several cases of therapeutic failure of praziquantel used for the treatment of urinary schistosomiasis have been reported. Alternative drugs, like niridazol and metrifonate, have shown a lower therapeutic effect and more side effects than praziquantel. Twenty-six Brazilian military men (median age of 29 years) with a positive urine parasitological exam who were part of a United Nation peace mission in Mozambique in 1994 were treated with 40 mg/kg body weight praziquantel, single dose. They swimmed in Licungo river (Mocuba city, Mozambique) during the weekends. After this, they presented haematuria, dysuria, polakiuria, and lumbar pain. Control cystoscopy examinations carried out between 6 and 24 months after each treatment (including two additional treatments at a minimum interval of 6 months) revealed the presence of viable eggs. Granulomas in the vesical submucosa were observed in 46.2 percent (12/26) of the individuals. A vesical biopsy confirmed the presence of granulomas in all of these patients and the presence of viable eggs in 34.3 percent (9/26) of individuals who no longer excreted eggs in urine. The eggs filled with miracidia showed characteristics of viability. Histopathological examination using different strains demonstrated therapeutic failure and the need for repeated treatment. In this study, we demonstrated a low efficacy of praziquantel in the treatment of schistosomiasis haematobia, and the necessity of the urinary bladder biopsy as criterion of cure.