Distribution of hepatitis B infection in Brazil: the epidemiological situation at the beginning of the 21 st century

Abstract Brazil was formerly considered a country with intermediate hepatitis B endemicity, with large heterogeneity between Brazilian regions and areas of high prevalence, especially in the Amazon basin. Systematic vaccination of children was initiated in 1998. Between 2004 and 2009, a large population-based study reported decreased prevalence in all regions of Brazil. This review analyzed the current hepatitis B epidemiological situation in Brazil through a systematic search of the scientific literature in MEDLINE, LILACS, and CAPES thesis database, as well as disease notifications to the Information System for Notifiable Diseases. The search strategy identified 87 articles and 13 theses, resulting in 100 total publications. The most recent results indicate reduced hepatitis B prevalence nationwide, classifying Brazil as having low endemicity. Most studies showed HBV carrier prevalence less than 1%. However, there are still isolated regions with increased prevalence, particularly the Amazon, as well as specific groups, such as homeless people in large cities and isolated Afro-descendant communities in the center of the country. This review alsao detected successful vaccination coverage reported in a few studies around the country. The prevalence of anti-HBs alone ranged from 50% to 90%. However, isolated and distant localities still have low coverage rates. This review reinforces the downward trend of hepatitis B prevalence in Brazil and the need to intensify vaccination strategies for young people and adults in specific regions with persisting higher HBV infection prevalence.

Orientation of the snail Biomphalaria straminea (Dunker, 1848) in response to light in a situation of selection

The behavioral response of Biomphalaria straminea to light was evaluted in terms of location of the snail in a Y-shaped aquarium in a situation of selection and of the rate (cm/hour) and direction of locomotion under homogeneous 9vertical) or differential (horizontal) lighting upon only one arm of the aquarium. The light source consisted of daylight fluorescent lamps with a spectrum close to that of natural light, with illumination varying from 28 to 350 lux. Analysis of the data showed that all animals, whether in groups or isolated, were attracted to light, although the time needed to approach the light source was 50% shorter for the former than for the latter. The rate of locomotion of B. straminea was 35% higher than observed in B. glabrata and 51% higher than that observed in B. tenagophila studied under similar conditions. The results are discussed in terms of social factors and geographical distribution of the three species.

Onchocerciasis in Ecuador: the situation in 1989

Details are given of the prevalence rates of onchocerciasis from the most recent surveys (1989) conducted in northern Ecuador. The disease has intensified and dispersed considerably due to migration of infected individuals and the presence of a highly efficient vector. Comparison of these data with those from two previous surveys carried out in 1982/83 and 1986 and correlated with entomological findings highly the danger of the formation of new foci of onchocerciasis in areas currently free of the disease. Recommendations are made for further entomological studies in areas either recently or likely to be affected by the disease where potential vectors are unknown or different to those registred in the Santiago focus. Invermectin treatment with local vector control in specific areas is advocated to reduce the disease to a low level of public health importance.

Dengue in Brazil - situation, transmission and control: a proposal for ecological control

This article discusses dengue in terms of its conceptual and historical aspects, epidemiological and clinical/pathological nature, and evolution up to the present situation in Brazil. The author discusses the ecological relationship in both the production of dengue and its control. Comparison is made between traditional dengue-control programs and a proposed socially-controlled program of an ecological nature without the use of insecticides. Stress is placed on interdisciplinary technical and scientific activity, broadbased participation by communities in discussing methodological aspects involving them, and prospective evaluation comparing the communities selected for intervention and control communities with regard to clinical and subclinical dengue cases and vector infestation rates in relation to climatic, socio-economic, and behavioural factors.

The situation of hepatosplenic schistosomiasis in Brazil today

Specific chemotherapy against schistosomiasis together with environmental changes occurring in endemic areas of Brazil are causing a revolution in the clinico-pathological presentation of the disease when comparing to date from 10 to 15 years ago. To update the subject, an inquire was made among the most experienced Brazilian investigators in this field. They agree that a decrease of about 50 to 70% in prevalence, and an even higher decrease in incidence are taking place in Brazil today. The prevalence of schistosome-infection has decreased in some areas and increased in other, with spreading sometimes occurring to peri-urban regions, indicating that schistosomiasis control depends on the application of multiple measures. General clinical and pathological manifestations related to hepatosplenic disease, such as ascites, gastric hemorrhages, big-spleen syndrome, cor pulmonale, glomerulopathy, etc. are also less severe nowadays than they used to be in the past

Therapy of Human African Trypanosomiasis: Current Situation

This paper is a review of the current situation of the treatment of human African trypanosomiasis. The existing approved drugs are old, toxic and/or expensive. Therapeutic failures are common. Several factors may contribute to the problems of chemotherapy, including differences in the epidemiology of the disease, difficulties in the diagnosis and staging of the infection, availability, distribution and pharmacologic properties of drugs, standardization of treatment regimens, response to therapy, follow-up period, and relapses and clinical trials. The new therapeutic approaches include the development and approval of new drugs, the use of new therapeutic regimens, the study of drug combinations, and the development of new formulations.

Chagas infection transmission control: situation of transfusional transmission in Brazil and other countries of Latin America

The transmission of the transfusion-associated Chagas disease is an important mechanism of its dissemination in several Latin American countries. The transmission risk depends on five factors: prevalence of infection in blood donors, degree of serological coverage, sensibility of used tests, safety of obtained results and infection risk. The Southern Cone Iniciative set off by the Pan-American Health Organization, in 1991, is contributing to the implementation of blood law in each endemic country, and to reduce the risk of transfusional transmission of this horrible disease. Despite the clear improvement of Brasilian hemotherapy after 1980 (with the creation of the Blood National Program - Pró-Sangue) and the significant reduction of the chagasic infection among its blood donors; socio-economic, politic and cultural unlevels, prevent it from reaching the necessary universality and security. In order to assure both, the Brazilian Ministry of Health decided to restructure its blood system. In May, 1998, a great program was launched, to reach a specific goal: Blood - 100% with quality safety in all its process until 2003. It was divided in 12 projects, intends to guarantee the quality and self sufficiency in blood and hemoderivates.

Dengue situation in Brazil by year 2000

Dengue virus types 1 and 2 have been isolated in Brazil by the Department of Virology, Instituto Oswaldo Cruz, in 1986 and 1990 respectively, after many decades of absence. A successful continental Aedes aegypti control program in the Americas, has been able to eradicate the vector in most countries in the 60's, but the program could not be sustained along the years. Dengue viruses were reintroduced in the American region and the infection became endemic in Brazil, like in most Central and SouthAmerican countries and in the Caribbean region, due to the weaning of the vector control programs in these countries. High demographic densities and poor housing conditions in large urban communities, made the ideal conditions for vector spreading. All four dengue types are circulating in the continent and there is a high risk of the introduction in the country of the other two dengue types in Brazil, with the development of large epidemics. After the Cuban episode in 1981, when by the first time a large epidemic of dengue hemorrhagic fever and dengue shock syndrome have been described in the Americas, both clinical presentations are observed, specially in the countries like Brazil, with circulation of more than one dengue virus type. A tetravalent potent vaccine seems to be the only possible way to control the disease in the future, besides rapid clinical and laboratory diagnosis, in order to offer supportive treatment to the more severe clinical infections.

Information and education in schistosomiasis control: an analysis of the situation in the State of Minas Gerais, Brazil

This paper presents the main ideas discussed in the round-table "Social and Educacional Aspects of Schistosomiasis Control", during the VII International Symposium of Schistosomiais. Considering the perspectives of schistosomiasis control in Brazil, it is described the example of the State of Minas Gerais , where the disease has been registered for more than seven decades. The importance of an extensive evaluation is now more important, considering the recent change in the Brazilian health system, since the Federal responsibility for the tropical diseases control programs have been replaced by the municipalities coordination. In this way, it is urgent to develop effective alternatives to assist the municipal staffs in the control task. In the specific case of health education, one observes a wide gap between the planned objectives and what is in fact carried out. Instant objectives and the utilization of traditional techniques prevail, which do not take into account the active participation of the population involved. Based on the authors' experience in the scientific and health education, the paper analyzes: (1) some data from a case study in the metropolitan region of Belo Horizonte, which presents the social representation and perception of schistosomiasis by the population; (2) an analysis of 35 different informative and educative materials used in Brazil since the sixties, and (3) some recommendations resulted from the studies that were carried out.

Southern Cone Initiative for the elimination of domestic populations of Triatoma infestans and the interruption of transfusion Chagas disease: historical aspects, present situation, and perspectives

Created in 1991 by the governments of Argentina, Bolivia, Brazil, Chile, Paraguay, and Uruguay, the Southern Cone Initiative (SCI) has been extremely important for Chagas disease control in this region. Its basic objective was to reach the interruption of this disease, chiefly by means of the elimination of the principal vector Triatoma infestans and by the selection of safe donors in the regional blood banks. After a summarized historic of SCI, the text shows the advance of technical and operative activities, emphasizing some factors for the initiative success, as well as some difficulties and constraints. The future of SCI will depend of the continuity of the actions and of political priority. Scientific community has been highly responsible for this initiative and its maintenance. At the side of this, national and international efforts must be involved and reinforced to assure the accomplishment of the final targets of SCI. Very specially, the Pan American Health Organization has cooperated with the Initiative in all its moments and activities,being the most important catalytic and technical factor for SCI success.

Current situation of Chagas disease in Central America

Chagas disease in Central America is known since 1913 when the first human case was reported in El Salvador. The other Central American countries reported their first cases between 1933 and 1967. On October 1997 was launched the Central American Initiative for Chagas Disease Control (IPCA). The objectives of this sub-regional Initiative are: (1) the elimination of Rhodnius prolixus in Central America; (2) the reduction of the domiciliary infestation of Triatoma dimidiata; and (3) the elimination of the transfusion transmission of Trypanosoma cruzi. Significant advancements being close to the elimination of R. prolixus in Central America and the control of the transfusion transmission has been a transcendent achievement for the sub-region. The main challenges that the IPCA will have in the close future are: developing effective strategies for control and surveillance of T. dimidiata; and surveillance of other emerging triatominae species like R. pallescens, T. nitida, and T. ryckmani.

Present situation and new strategies for Chagas disease chemotherapy: a proposal

Treatments for Chagas disease have been administered since the first attempts by Mayer & Rocha Lima (1912, 1914) and up to the drugs currently in use (nifurtimox and benznidazole), along with potential drugs such as allopurinol and first, second and third-generation antifungal agents (imidazoles and triazoles), in separate form. Several diseases such as tuberculosis, leprosy and AIDS only came under control after they were treated with associations of drugs with different mechanisms of action. This not only boosts the action of the different compounds, but also may avoid the development of parasite resistance .To this end, over the short term, we propose experimental studies on laboratory animals and clinical trials with the following associations: (i) nifurtimox (8 mg/kg/day) + benznidazole (5 mg/kg/day) x 60 consecutive days; (ii) nifurtimox (8 mg/kg/day) or benznidazole (5 mg/kg/day) + allopurinol (8-10 mg/kg/day) x 60 days and (iii) nifurtimox (8 mg/kg/day) or benznidazole (5 mg/kg/day) + ketoconazole, fluconazole or itraconazole (5-6 mg/kg/day) x 60 consecutive days. The doses of the drugs and the treatment schedules for the clinical trials must be adapted according to the side effects. From these, other double or triple associations could be made, using drugs with different mechanisms of action. This proposal does not exclude investigations on new drugs over the median and long terms, targeting other aspects of the metabolism of Trypanosoma cruzi. Until such time as the ideal drug for specific treatment of Chagas disease might be discovered, we need to develop new strategies for achieving greater efficacy with the old drugs in associations and to develop rational experimentation with new drugs.

Current situation and perspectives regarding human Chagas disease in midwestern of the state of Minas Gerais, Brazil

Recognising the importance of Chagas disease in Brazil, Bambuí set up epidemiological surveillance for Chagas disease in 1974 and was the first municipality to do so. To ascertain the current epidemiology of Chagas disease in this municipality, 1.782 blood samples from the general population were analysed; 7.7% of samples were found to be seropositive for Chagas disease. A strong positive correlation between increasing age and Chagas disease was evident in both genders, with the highest prevalence in individuals aged over 60 years. Clinically, the cardiodigestive form of Chagas disease was the most common in these samples. These data confirm the interruption of Trypanosoma cruzi transmission, in parallel with a still important residual morbidity of Chagas disease in the county, thus supporting political decisions that will prioritise epidemiological surveillance and medical treatment of Chagas disease in the coming years.

Malaria on the Guiana Shield: a review of the situation in French Guiana

In a climate of growing concern that Plasmodium falciparum may be developing a drug resistance to artemisinin derivatives in the Guiana Shield, this review details our current knowledge of malaria and control strategy in one part of the Shield, French Guiana. Local epidemiology, test-treat-track strategy, the state of parasite drug resistance and vector control measures are summarised. Current issues in terms of mobile populations and legislative limitations are also discussed.