Impact of antihelminthic treatment on infection by Ascaris lumbricoides, Trichuris trichiura and hookworms in Covas, a rural community of Pernambuco, Brazil

This work aims to evaluate the impact of drug treatment on infection by Ascaris lumbricoides (Al), Trichuris trichiura (Tt) and hookworms (Hook) in a rural community from the sugar-cane zone of Pernambuco, Brazil. Four parasitological surveys were carried out from March 2001 to March 2002. Individual diagnosis was based on eight slides (four by the Kato-Katz method and four by the Hoffman method) per survey. Infected subjects were assigned to two groups for treatment with either albendazole (n = 62) or mebendazole (n = 57). Prevalence of infection fell significantly (p < 0.05) one month after treatment: Al (from 47.7% to 6.6%); Tt (from 45.7% to 31.8%) and Hook (from 47.7% to 24.5%). One year after treatment, infections by Tt and Hook remained significantly below pre-control levels. A substantial decrease in single-infection cases and multiple infections was found. Egg-negative rate was significant for Al (94.0%), Hook (68.3%) but not for Tt (45.5%), and did not differ significantly between subjects treated with mebendazole or albendazole. Egg counts fell significantly in the individuals remaining positive for Tt. It is recommended that antihelminthic treatment should be selective and given at yearly intervals preferably with albendazole, due to its cost-effectiveness.

Replacing oxamniquine by praziquantel against Schistosoma mansoni infection in a rural community from the sugar-cane zone of Northeast Brazil: an epidemiological follow-up

A group of 52 villagers was followed-up for three years regarding Schistosoma mansoni infection. All villagers were periodically surveyed by the Kato-Katz method. In March 1997 and March 1998 the positives were treated with oxamniquine (15-20 mg/kg), and in March 1999, with praziquantel (60 mg/kg). All infection indices decreased substantially between March 1999 and March 2000: prevalence of infection (from 32.7% to 21.2%), prevalence of moderate/heavy infection (from 7.7% to 1.9%), intensity of infection (from 23.1 epg to 7.4 epg) and reinfection (from 35.7% to 14.3%). Negativation increased from 53.8 to 82.4. An optimistic prognostic is assumed in the short term for the introduction of praziquantel in the study area.

Specific situations related to acute schistosomiasis in Pernambuco, Brazil

The present work reports on two epidemiological episodes resulting in acute schistosomiasis involving wealthy persons living in the State of Pernambuco, Brazil. The authors discuss the epidemiological, clinical and serologic characteristics of the acute infections and also the way in which the conditions for transmission occurred.

Evolutionary relationships and biogeography of Biomphalaria (Gastropoda: Planorbidae) with implications regarding its role as host of the human bloodfluke, Schistosoma mansoni

The wide geographic distribution of Schistosoma mansoni, a digenetic trematode and parasite of humans, is determined by the occurrence of its intermediate hosts, freshwater snails of the genus Biomphalaria (Preston 1910). We present phylogenetic analyses of 23 species of Biomphalaria, 16 Neotropical and seven African, including the most important schistosome hosts, using partial mitochondrial ribosomal 16S and complete nuclear ribosomal ITS1 and ITS2 nucleotide sequences. A dramatically better resolution was obtained by combining the data sets as opposed to analyzing each separately, indicating that there is additive congruent signal in each data set. Neotropical species are basal, and all African species are derived, suggesting an American origin for the genus. We confirm that a proto-Biomphalaria glabrata gave rise to all African species through a trans-Atlantic colonization of Africa. In addition, genetic distances among African species are smaller compared with those among Neotropical species, indicating a more recent origin. There are two species-rich clades, one African with B. glabrata as its base, and the other Neotropical. Within the African clade, a wide-ranging tropical savannah species, B. pfeifferi, and a Nilotic species complex, have both colonized Rift Valley lakes and produced endemic lacustrine forms. Within the Neotropical clade, two newly acquired natural hosts for S. mansoni (B. straminea and B. tenagophila) are not the closest relatives of each other, suggesting two separate acquisition events. Basal to these two species-rich clades are several Neotropical lineages with large genetic distances between them, indicating multiple lineages within the genus. Interesting patterns occur regarding schistosome susceptibility: (1) the most susceptible hosts belong to a single clade, comprising B. glabrata and the African species, (2) several susceptible Neotropical species are sister groups to apparently refractory species, and (3) some basal lineages are susceptible. These patterns suggest the existence of both inherent susceptibility and resistance, but also underscore the ability of S. mansoni to adapt to and acquire previously unsusceptible species as hosts. Biomphalaria schrammi appears to be distantly related to other Biomphalaria as well as to Helisoma, and may represent a separate or intermediate lineage.

[Evaluation of control measures implemented from 1977 to 1996 in the endemic area of schistosomiasis in Pernambuco, Brazil]

This study assesses the evolution of schistosomiasis in the endemic area of Pernambuco, using data from five campaigns of chemotherapy control carried out by national health programmes from 1977 to 1996. Analysis of the data showed that: a) the proportion of municipalities with prevalence above 25% was significantly higher in the coastal-forest zone than in the zone of transitional vegetation Agreste in the four evaluations made in the endemic area; b) the prevalence of infection decreased in both zones even when the interval between campaigns were more than five years. The last survey (1996) indicated a predominance of municipalities with prevalences below 25%. However, the majority of these municipalities had localities with prevalence above 50%. A proposal is presented for the identification of the problematic localities, where complementary measures to chemotherapy, such as systematic snail control, improved sanitation, health education and community mobilization, are still necessary.

[An outbreak of acute schistosomiasis at Porto de Galinhas beach, Pernambuco, Brazil]

We recently confirmed several cases of acute schistosomiasis in Porto de Galinhas beach, Northeast Brazil. A total of 662 patients were diagnosed by parasitological and clinical examinations. The infection likely occurred during the September 7 national holiday, when heavy rainfall flooded the Ipojuca River and people were infected when the water covered their yards. Families were continuously exposed to infection for a period of three weeks until the water had completely dried up. Previous investigation suggests that snail vectors were introduced as a result of landfill in marshy areas. The swamp-flooding of such areas facilitated the emergence of slums surrounded by snail breeding sites. Heavy rainfall caused open-air sewage ditches to overflow, allowing for infection of snails by Schistosoma mansoni. Thus, continuous floods were responsible for the spread of human infection. Clinical and laboratory results identified 62% of acute cases of S. mansoni. Complementary studies are being conducted to define the impact and epidemiological meaning of the acute schistosomiasis outbreak.

[Ecoepidemiology of urban schistosomiasis in Itamaracá Island, Pernambuco, Brazil]

INTRODUCTION

In 1988, 22 autochthonous cases from accidental exposure were registered in Forte Orange beach, Itamaracá Island, Pernambuco, Brazil. All cases occurred in middle-to-upper class individuals who were vacationing in the island. After the cases were identified, the major objective was to find breeding sites of schistosomiasis vectors and correlate the biological factors with the environmental conditions.

METHODS

The environmental characteristics of the beach before human occupation were obtained from several documents. Also, a one-year malacological survey was conducted with monthly collection of mollusks, and the determination of their infectivity rates.

RESULTS/CONCLUSIONS

The malacological survey was able to identify 20 breeding sites of Biomphalaria glabrata and 28 capture station were set up. Snails were collected and examined each month throughout a whole year. The results show a seasonal variation in the mollusk population density associated with infection rates and types of breeding sites. The importance of this new epidemiological profile of schistosomiasis in the State of Pernambuco relies on the fact that it can be related with the drastic human interference on the environment. Ecological, environmental, and demographic factors as well as the epidemiological characteristics of the disease have social and economic repercussions.

[Occurrence of snail vectors of schistosomiasis in a dam of the semi-arid region of Pernambuco State, Brazil]

The semi-arid region of Pernambuco state is not an endemic or focal area for schistosomiasis. The present work registers the occurrence of Biomphalaria straminea in a local dam with favorable chemical-physical characteristics to the proliferation of these mollusks. This observation gets the attention for the possibility of the introduction of the disease in this semi-arid region due to the growing multiplication of these dams.

[Intestinal schistosomiasis and its control in North-East Brazil]

Intestinal schistosomiasis is endemic in the sugar cane belt near the coast of North-East Brazil. The environment and poor living conditions of the agricultural workers of this area combine to perpetuate the transmission of this disease. However, a new epidemiological pattern is emerging on the coast of Pernambuco State, where workers from the endemic area are building weekend homes without proper drainage. National control programs have led to a dramatic reduction in severe infections. However, they have not yet succeeded in stopping disease transmission altogether. The transfer of responsibility for control to local public health structures, which is currently underway, should improve the situation.

Schistosomiasis control based on repeated chemotherapy in a rural village of the sugar-cane zone in northeast Brazil

A schedule of repeated chemotherapy with oxamniquine, consisting of biannual treatment of school-aged (7-13 years) children and annual treatment of all other age groups, was used in a representative rural village from a highly endemic area of schistosomiasis in Pernambuco. Significant reductions in infection were obtained only after two cycles of treatment, as the overall prevalence decreased from 72.6% to 41.7% and the geometric mean egg counts per gram of faeces among positives fell from 188.4 to 76. In a school-aged cohort (n = 29) three treatments at six-month intervals were necessary to significantly reduce the proportion of positives (from 75.9% to 51.7%). In a cohort of children under 7 years of age (n = 20) the proportion of positives actually increased (from 30% to 45%) despite two annual treatments. Water contact was intense and host snail density was relatively high. As there is no short-term perspective of improved sanitation, auxiliary measures such as focal mollusciciding are needed for an adequate control of schistosomiasis in this and alike areas.

Epidemiology and anthropology: an integrated approach dealing with bio-socio-cultural aspects as strategy for the control of endemic diseases

The control of endemic diseases has not attained the desired level of effectiveness in spite of the use of modern efficient technologies. The classic interventionist approach for the control of schistosomiasis is centered on systemic control of the snail hosts combined to large scale medical treatment and is usually carried out without social preoccupation due to the assisted communities. It is easy to understand the interest and the ethical compromise of public health research while producing studies in which the biological and social determinants as well as the cultural components should be considered and also encompass the historical dimensions and symbolic representations. In face of the recent political decision in favor of decentralizations of health administration to municipal level, we suggest, in the present paper, an integrated approach for the epidemiological diagnosis of an endemic situation at local level. Theoretical and methodological aspects from both, epidemiology and anthropology are discussed. Epidemiological methods can be used to detect the dependent variables (those related to the human infection) and the independent variables (demographic, economic, sanitary and social). Another methodological approach of anthropological/ethnographic nature can be conducted in order to make an articulation of the knowledge on the various dimensions or determinant levels of the disease. Mutual comprehension, between researchers and the people under investigation, on the dynamic transmission process would be relevant for a joint construction, at local level, of programmed actions for the control of endemic diseases. This would extend reflections on the health/disease process as a whole.

Primary leiomyosarcoma of bone: report of two cases in extragnathic bones

Primary leiomyosarcoma of extragnathic bone is rare; fewer than 50 cases are found in the literature. We report on two patients, adult men, with tumors located on the long bones (close to the knee joint). Radiographically, the tumors were shown as purely destructive, osteolytic, and infiltrative lesions. The diagnosis was based on light microscopy, including immunohistochemistry and ultrastructural examination. The tumor cells were uniformly positive for vimentin and muscle actin, but not for desmin. In one case, the cells were also positive for alpha-smooth muscle actin. Electron microscopy showed definitive smooth muscle differentiation, including cytoplasmic filaments with focal densities. Both patients died of pulmonary metastases.

Factors involved in Schistosoma mansoni infection in rural areas of northeast Brazil

Two contiguous villages in Tracunhaém county (State of Pernambuco), endemic for schistosomiasis, were studied: Itapinassu (138 inhabitants) and São Joaquim (91 inhabitants). Agriculture predominates in the former region while ceramics is the main activity in the latter. Although no statistical difference was found regarding prevalence, severe infection (> 400 epg) predominated in Itapinassu, probably related to the kind of occupation. No association was found between parasite burden and severity of disease, in spite of the high infection rates for Schistosoma mansoni in both communities (approx. 60%). Typical epidemiological features of schistosomiasis such as age-related prevalences and intensities of infection (high in children, low in adults) were also mutual characteristics. Nutritional status determined through anthropometric evaluation was carried out by measuring specific anthropometric indicators. A deficit of energy intake, as well as vitamin A and riboflavin deficiencies were detected. The prevalence of moderate or severe undernutrition in patients under 18 years old was 21.9% in Itapinassu and 24.1% in São Joaquim. In this group an association was found between prevalence of schistosomiasis and chronic undernutrition. Similarly, for patients over 18 year old the prevalence of undernutrition was higher than 20%. However, in this case no association between nutritional status and either prevalence of schistosomiasis or parasite burden could be detected. The two communities had not been treated for eight years.

[Schistosomiasis: reproduction and expansion of the endemia to the state of Pernambuco in Brazil]

Schistosomiasis mansoni can be considered an important public health problem in Northeastern Brazil, in spite of the reduction in the prevalence of the hepatosplenic clinical forms which have been attributed to the large scale use of chemotherapy in this country. However, the rise in the prevalence rates and the spread of this endemic disease to new areas show that schistosomiasis is assuming its must cruel expression: less lethal but more greatly incapacitating in terms of irreversible physical and moral damage to human beings. The state of Pernambuco presents growing rates for schistosomiasis infection in humans. The epidemiological profile of this disease displays high and consistent prevalence rates (up to 80%) in rural areas, and new cases of acute infection on the coast, where schistosomiasis has recently been introduced. The reproduction and expansion of this endemic disease can be better understood on the basic of a conception of structural and historical causation. The disease construction process should be reconstructed in the light of biological as well as the social, political and cultural factors which are jointly responsible for the present endemic situation. Within that frame work, the historical and socioeconomic features that interact with the parasite and give rise to the present proportions of the schistosomiasis epidemic in Pernambuco are discussed. The mode of occupation and use of the land, unemployment, under-nutrition, migration, etc., raise the question of the growing difficulties confronting the control of the disease, both in rural areas where populations are extremely mobile as well as in the poorly organized urban population. Epidemiological investigation is fulfilling its role in its attempts to understand the complex relationships of an intrinsecally social nature of the health/disease process between health problems and the quality of life for the purpose of producing consistent disease control models.

The bioecology of snail vectors for schitosomiasis in Brazil

This paper describes the ecology of two species of Biomphalaria: B.glabrata and B. straminea. These species have been intensively studied in Brazil and in other countries since the 1950s. The literature in this area can be broadly subdivided into three categories, linked to three distinct historical periods: 1) an accumulated store of early studies carried out in the laboratory and in the field; 2) the development of quantitative ecological models; and 3) the development of an alternative methodology for breeding snails under seminatural conditions.

[Malacologic diagnostic methods]

Specific identification of the snail vectors: (a) shell features; (b) animal features (genital organs); (c) biochemical techniques (electrophoresis). The snail infection rates: (a) exposure to light and cercarial identification; (b) snail crushing and identification or the larval forms in the tissues.

Long-term controlled field experiment on the competition between two species of Biomphalaria (Mollusca, Basommatophora), the snail vectors of Schistosoma mansoni in Northeastern Brazil

A long-term controlled field experiment on the interactions of the populations of Biomphalaria glabrata (target population) and B. straminea (competitor) was carried out in the county of Alhandra, state of Paraíba, Brazil, during the period 1980 through 1989. Results obtained in the current paper show that the snail B. straminea has strong competitive advantages over B. glabrata. In six out of nine streams the native population of B. glabrata were totally excluded and replaced by B. straminea. There is evidence showing that seasonal dryness has marked influence on the phenomenon studied in this paper. In all the streams were B. straminea already predominated, return of B. glabrata was never observed.

[Incidence of primary benign and malignant neoplasms and bone pseudotumoral lesions. An epidemiologic analysis of 585 cases diagnosed at the Faculdade de Medicina of the Universidade Federal de Minas Gerais]

The authors present an epidemiological study of 585 primary bone neoplasms and tumor-like lesions in order to investigate their incidence and distribution according to age, sex and skeletal location. A statistical agreement between the pertinent literature and the collected data was found. In this series, the most common benign neoplasms were the osteochondroma (45.3%) followed by chondroma (19.6%). Among the intermediate and malignant neoplasms, osteosarcoma was the most frequent (30.0%) followed by myeloma (16.0%). Fibrous dysplasia accounted for 46.6% of all tumor-like lesions, followed by solitary bone cyst (18.6%).

Phaeohyphomycotic cyst: a clinicopathologic study of the first four cases described from Brazil

Four cases of phaeohyphomycosis in the form of chronic and isolated cysts are presented. The cysts were strictly confined to the subcutaneous tissue, with no involvement of the corresponding skin. Patients were asymptomatic, without satellite lesions or regional lymphadenopathy. The clinicopathologic importance of this type of phaeohyphomycosis is discussed. As far as we know, our cases are the first described from Brazil.

[Precancerous lesions associated with atrophic chronic gastritis and gastric peptic ulcer]

Among the gastric lesions related to an increased risk for gastric cancer (precancerous conditions) two have deserved special attention, i.e., atrophic gastritis and peptic ulcer. In this paper the authors study the incidence of glandular dysplasia in atrophic gastritis and gastric peptic ulcer. In 148 cases of atrophic gastritis dysplastic lesions were diagnosed in 92 (62,0%): 63 cases (68,4%) with mild dysplasia, 25 cases (27,0%) with moderate dysplasia and 4 cases (4,3%) with severe dysplasia. In 329 gastric peptic ulcers examined there were 51 (15,5%) with dysplastic lesions: in 34 cases (66,6%) there was mild dysplasia, 12 cases (23,5%) moderate dysplasia and (9,8%) severe dysplasia. A prospective study with histological multiple sections from the stomach would be helpful for better understanding of these precancerous lesions.

[Vincamine in patients with cerebral vascular insufficiency]

The effects of the treatment with vincamine in 20 patients with cerebral vascular insufficiency are reported. The patients were previously submitted to the following tests: neurologic examination, electroencephalography, laboratory tests, psychometry (memory, intellective capability, concentrated attention, abstract reasoning and personality tests). Patients were medicated with vincamin in a 40 mg dose within 24 hours during approximately a 150 days period, after which were again submitted to an identical analysis. The results obtained revealed that in a reasonable percentage of the cases vincamin is an useful medication in controlling the clinical manifestations of the cerebral vascular insufficiency, an improvement being demonstrated in the retrograde and anterograde deficit rate observed in objective tests. An improvement was also noticed in the electroencephalograpric pattern of a few patients.