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PubMed2005

Prevalence, incidence, and residual risk of human immunodeficiency virus among community and replacement first-time blood donors in São Paulo, Brazil.

BACKGROUND: Concerted efforts have been directed toward recruitment of community rather than replacement donors in Brazil. Time trends and demographic correlates of human immunodeficiency (HIV) prevalence and incidence among first-time (FT) donors in Brazil were examined by donation type. HIV residual risk from FT-donor transfusions, and projected yield of p24 antigen and nucleic acid test (NAT) screening were estimated. STUDY DESIGN AND METHODS: HIV prevalence data and seroreactive specimens were obtained at Fundação Pró-Sangue/Hemocentro-de-São Paulo from 1995 to 2001. To estimate incidence, confirmed-positive samples from July 1998 through December 2001 were tested with a less-sensitive (detuned) enzyme immunoassay to detect recent seroconversions. Incidence data were used to estimate residual risk and p24 and NAT yield based on published window periods (WPs). RESULTS: HIV prevalence was 22 percent higher among the FT community donors than replacement donors (19.6 vs. 16.1 per 10,000; p < 0.01) and 48 percent higher among men than women (19.1 vs. 12.9; p < 0.01). In the multivariable logistic regression, both variables remained significant predictors of HIV prevalence. HIV prevalence decreased from 20.4 (1995) to 13.1 per 10,000 FT donations (2001). HIV incidence was 2.7 per 10,000 person-years. The estimated rate of infected antibody-negative donations was 14.9 per 1,000,000 units (95% confidence interval, 9.8-20.0). It was estimated that addition of p24 antigen, minipool NAT, and individual-donation NAT assays would detect 3.9 (2.0-5.8), 8.3 (5.3-11.3), and 10.8 (7.1-14.5) WP units per 1,000,000 FT donations, respectively. CONCLUSION: HIV incidence and residual transfusion risk estimates are approximately 10 times higher in Brazil FT donors compared to US and European FT donors. Community FT donors had higher HIV prevalence than replacement FT donors. The yield of p24 antigen or RNA screening will be low in Brazilian donors, but substantially higher than in US donors.

Adult↗
PubMed2000

Prevalence of celiac disease among blood donors in Brazil.

OBJECTIVE: There are no studies on the prevalence of celiac disease (CD) in either Brazil or, as far as we know, South America. The aim of this study was to determine the prevalence of CD in healthy blood donors in the city of Brasilia, Brazil. METHODS: Sera were obtained, independently of age and gender, from an unselected group of 2045 blood donors attending the Hematological Center of Brasilia. An IgG antigliadin antibody (AGA) test was used as a first-level screening step, followed by IgA-AGA test, serum IgA antiendomysium (EMA), and total serum IgA determination performed in all sera showing abnormally high IgG-AGA results. Jejunal biopsy was suggested for all subjects showing at least one of the following: IgA-EMA positivity; IgG-AGA and IgA-AGA positivity; IgG-AGA positivity and selective IgA deficiency. AGA was determined by an enzyme-linked immunosorbent assay (ELISA) technique and IgA-EMA was ascertained by indirect immunofluorescence on cryostat sections of monkey esophagus. Jejunal mucosa samples were obtained with a Watson capsule. RESULTS: Sixty-two (3.03%) blood donors had IgG-AGA above the cut-off values. Fifty-eight individuals showed isolated high values of IgG-AGA, whereas four had simultaneously increased IgG and IgA-AGA. Three patients had positive IgA-EMA test (one with both IgG- and IgA-AGA and two with only IgG-AGA) and underwent jejunal biopsies that disclosed complete villous atrophy associated with an increased number of intraepithelial lymphocytes and hypertrophic criptae. In this study group, the prevalence of biopsy-proven celiac disease was 1.47 +/- 1.66 in 1000 subjects. CONCLUSIONS: We found a prevalence of undiagnosed CD of 1:681 among apparently healthy blood donors. These preliminary results support the view that CD is not a rare disease in Brazil.

Adolescent↗
PubMed1997

Moyamoya disease in Brazil.

INTRODUCTION: Moyamoya disease was first believed to be confined to Japan, but over the years it has been reported all over the world. We report seven cases from the University Hospital of the Faculty of Medicine of Ribeirão Preto, University of São Paulo with a review of the previously described cases in Brazil. MATERIAL AND METHODS: The diagnosis was based on the diagnostic criteria of the Research Committee on Spontaneous Occlusion of the Circle of Willis. RESULTS: Five patients presented ischemic and two hemorrhagic events. The meta-analysis of the six cases previously described in Brazil showed that only two were true moyamoya disease according to the diagnostic criteria. CONCLUSION: We can assume that the real frequency of moyamoya disease has been underestimated in Brazil.

Adolescent↗
PubMed1992

Persistent diarrhea in northeast Brazil: etiologies and interactions with malnutrition.

With the improved control of acute diarrheal illness mortality with oral rehydration therapy, persistent diarrhea is now emerging as a major cause of childhood mortality in tropical developing areas like the impoverished populations in Brazil's Northeast. "Graveyard surveillance" in the rural community of Guaiuba in northeastern Brazil revealed fully half of the 70% diarrhea mortality was due to persistent diarrheal illnesses. Furthermore, 11% of 14 or more diarrheal illnesses per child per year in an urban slum in Fortaleza persisted beyond 14 days, a definition that clearly identified the high risk children for heavy diarrhea burdens. Not only did heavy diarrhea burdens ablate the key "catch-up" growth seen in severely malnourished children and in children following previous diarrheal illnesses, but malnutrition significantly predisposed children to a greater incidence and duration of diarrhea as well as a greater incidence of persistent diarrhea. Etiologic studies of 37 children presenting with persistent diarrhea to Hospital das Clinicas in Fortaleza revealed that Cryptosporidium (in 13%) and enteroadherent E. coli (36% with aggregative, 29% with diffuse and 13% with localized adherence to HEp-2 cells) were the predominant potential pathogens found in the stool or upper small bowel. These findings suggest that persistent diarrhea is emerging as an important health problem in Brazil's Northeast, that it identifies a high risk child for heavy diarrhea burdens, that important interactions occur with malnutrition and that Cryptosporidium and enteroadherent E. coli warrant further study as potential etiologies of this major cause of morbidity and mortality.

Animals↗
PubMed2001

Serosubtypes and PorA types of Neisseria meningitidis serogroup B isolated in Brazil during 1997--1998: overview and implications for vaccine development.

Meningococcal disease caused by N. meningitidis serogroup B (MenB) has been endemic in Brazil since 1997. In this study, we determined the prevalence of serosubtypes of MenB isolated in 10 Brazilian states and the Federal District during 1997 and 1998 and investigated the extent of PorA VR sequence variation among the most prevalent serosubtypes to evaluate the possible use of an outer membrane vesicle (OMV)-, PorA-based vaccine to prevent meningococcal disease in Brazil. During this period, a total of 8,932 cases of meningococcal disease were reported. Only 42% (n = 3,751) of the reported cases were laboratory confirmed, and about 60% (n = 2,255) of those were identified as MenB. Among 1,297 MenB strains selected for this study, the most prevalent serosubtypes were P1.19,15 (66%), P1.7,1 (11%), and P1.7,16 (4%). PorA VR typing showed that 91% of the P1.19,15 strains analyzed had VR1 and VR2 sequences identical to those of the prototype strain. No sequence variation was detected among the 40 strains representing all isolated MenB P1.7,16 strains in the three southern states, where this serosubtype accounts for 75% of the serosubtypes identified. Similarly, all P1.7,1 strains were identified by PorA typing as P1.7-1,1. Although further improvements in the reporting of cases and collection of strains in Brazil are needed, our data suggest that a trivalent OMV-based vaccine prepared with PorA types P1.19,15, P1.7-1,1, and P1.7,16 may be appropriate to control serogroup B meningococcal disease in most of the Brazilian states.

Brazil↗
PubMed2026

Healthcare-facility-based SARS-CoV-2 genomic surveillance in Brazil: experience from the global action in healthcare network.

UNLABELLED: Genomic sequencing is essential to effectively monitor the SARS-CoV-2 evolution and spread of its lineages. Healthcare-facility-based SARS-CoV-2 genomic surveillance has been proposed as a valuable strategy, considering the characteristics of its target population. As part of the Centers for Disease Control and Prevention's Global Action in Healthcare Network program, this study aimed to describe the distribution and frequency of SARS-CoV-2 lineages in two tertiary-care hospitals in Brazil, where the genomic sequencing capacity is limited. Whole-genome sequencing of SARS-CoV-2 samples obtained from 993 healthcare workers (75.4%) and inpatients (24.6%) was analyzed between February 2023 and August 2024. In total, 113 distinct lineages were identified. Notably, we observed a temporal replacement of predominant lineages corresponding to three distinct epidemic waves: the first wave dominated by XBB.1.5 and XBB.2.3 (February 2023 to June 2023), the second by GK.1.1 and JD.1.1 (September 2023 to December 2023), and the third by JN.1 and JN.1.9 (January 2024 to April 2024). JN.1.9 was the only lineage with a significantly higher prevalence among healthcare workers compared to inpatients. Additionally, we identified cases of co-infection with genetically distinct variants, underscoring the potential for healthcare-based monitoring to capture events relevant to viral evolution. Overall, our findings were consistent with those observed across Brazil, suggesting that this strategy may be valuable for SARS-CoV-2 genomic surveillance. They also indicate a clear temporal pattern of lineage replacement, reflecting successive waves driven by emerging variants and rapid global dissemination. IMPORTANCE: Genomic surveillance of SARS-CoV-2 remains essential for identifying emerging variants with increased transmissibility, immune escape, or pathogenicity. While most genomic surveillance efforts focus on community-based sampling, a healthcare-facility-based strategy may offer a complementary approach. In this study, we describe SARS-CoV-2 lineage dynamics over an 18-month period among healthcare workers and hospitalized patients in southern Brazil. Our findings align closely with regional and national trends, supporting the value of healthcare-facility-based SARS-CoV-2 genomic surveillance for documenting the local genomic landscape and demonstrating the feasibility and value of this approach in settings with limited genome sequencing capacity. Additionally, this approach may be applicable to other respiratory viruses in healthcare settings; however, further studies would be needed to confirm this.

Humans↗
PubMed1993

Health care in Brazil.

Brazil has great geopolitical importance because of its size, environmental resources, and potential economic power. The organisation of its health care system reflects the schisms within Brazilian society. High technology private care is available to the rich and inadequate public care to the poor. Limited financial resources have been overconcentrated on health care in the hospital sector and health professionals are generally inappropriately trained to meet the needs of the community. However, recent changes in the organisation of health care are taking power away from federal government to state and local authorities. This should help the process of reform, but many vested interests remain to be overcome. A link programme between Britain and Brazil focusing on primary care has resulted in exchange of ideas and staff between the two countries. If primary care in Brazil can be improved it could help to narrow the health divide between rich and poor.

Brazil↗
PubMed2006

Evaluation of the impact of the Family Health Program on infant mortality in Brazil, 1990-2002.

OBJECTIVE: To use publicly available secondary data to assess the impact of Brazil's Family Health Program on state level infant mortality rates (IMR) during the 1990s. DESIGN: Longitudinal ecological analysis using panel data from secondary sources. Analyses controlled for state level measures of access to clean water and sanitation, average income, women's literacy and fertility, physicians and nurses per 10,000 population, and hospital beds per 1,000 population. Additional analyses controlled for immunisation coverage and tested interactions between Family Health Program and proportionate mortality from diarrhoea and acute respiratory infections. SETTING: 13 years (1990-2002) of data from 27 Brazilian states. MAIN RESULTS: From 1990 to 2002 IMR declined from 49.7 to 28.9 per 1,000 live births. During the same period average Family Health Program coverage increased from 0% to 36%. A 10% increase in Family Health Program coverage was associated with a 4.5% decrease in IMR, controlling for all other health determinants (p<0.01). Access to clean water and hospital beds per 1,000 were negatively associated with IMR, while female illiteracy, fertility rates, and mean income were positively associated with IMR. Examination of interactions between Family Health Program coverage and diarrhoea deaths suggests the programme may reduce IMR at least partly through reductions in diarrhoea deaths. Interactions with deaths from acute respiratory infections were ambiguous. CONCLUSIONS: The Family Health Program is associated with reduced IMR, suggesting it is an important, although not unique, contributor to declining infant mortality in Brazil. Existing secondary datasets provide an important tool for evaluation of the effectiveness of health services in Brazil.

Brazil↗
PubMed2004

A survey of indigenous microbial hydrocarbon degradation genes in soils from Antarctica and Brazil.

Total community DNA from 29 noncontaminated soils and soils impacted by petroleum hydrocarbons and chloro-organics from Antarctica and Brazil were screened for the presence of nine catabolic genes, encoding alkane monooxygenase or aromatic dioxygenases, from known bacterial biodegradation pathways. Specific primers and probes targeting alkane monooxygenase genes were derived from Pseudomonas putida ATCC 29347 (Pp alkB), Rhodococcus sp. strain Q15 (Rh alkB1, Rh alkB2), and Acinetobacter sp. ADP-1 (Ac alkM). In addition, primers and probes detecting aromatic dioxygenase genes were derived from P. putida ATCC 17484 (ndoB), P. putida F1 (todC1), P. putida ATCC 33015 (xylE and cat23), and P. pseudoalcaligenes KF707 (bphA). The primers and probes were used to analyze total community DNA extracts by using PCR and hybridization analysis. All the catabolic genes, except the Ac alkM, were detected in contaminated and control soils from both geographic regions, with a higher frequency in the Antarctic soils. The alkane monooxygenase genes, Rh alkB1 and Rh alkB2, were the most frequently detected alk genes in both regions, while Pp alkB was not detected in Brazil soils. Genes encoding the aromatic dioxygenases toluene dioxygenase (todC1) and biphenyl dioxygenase (bphA) were the most frequently detected in Antarctica, and todC1 and catechol-2,3-dioxygenase (cat23) were the most frequent in Brazil soils. Hybridization analysis confirmed the PCR results, indicating that the probes used had a high degree of homology to the genes detected in the soil extracts and were effective in detecting biodegradative potential in the indigenous microbial population.

Acinetobacter↗
PubMed2006

International student exchange and the medical curriculum: evaluation of a medical sciences translational physiology course in Brazil.

The objective of the present study was to conduct a short-term international course on translational physiology for medical students from Wright State University and the University of Iowa. The goals were to 1) provide students with an exposure to the academic, cultural, and medical environments in Brazil; 2) promote awareness of the global medical community; and 3) provide an academic course focused on translational physiology. An evaluation of the students was conducted to determine whether such a short-term course might be useful in the medical curriculum. The 2-wk course was held in the summer of 2005 at the University of São Paulo School of Medicine in Ribeirão Preto, Brazil, for 23 American students. The program included presentations of basic and clinical topics, meetings with medical students, and clinical presentations. The program finished with student attendance at a scientific meeting sponsored by the Brazilian Society of Hypertension. Student surveys evaluated issues related to perceived treatment, Brazilian medical school environment, culture and personal attributes, and career aspirations. The international Medical Sciences Translational Physiology course for medical students provided a brief, but intense, experience. It gave students a picture of the medical environment in Brazil and an appreciation for the differences and similarities in cultures. Most students reported that it was a positive experience that would be beneficial to their careers. In conclusion, a short-term international course provides an efficient means for medical students to experience aspects of global medical science.

Brazil↗
PubMed2007

Quality of life of older adults in Canada and Brazil.

In this study, we examined the factors contributing to quality of life (QOL) of older adults in regions of Canada and Brazil. The WHOQOL-BREF and a demographic data sheet were administered to random samples of 202 older adults from Canada and 288 from Brazil. Ratings on overall QOL and on the physical, psychological, and environmental domains were higher in the Canadian sample. Social domain scores were not significantly different. The authors found the same pattern of factors (health satisfaction, enough money, meaning in life, and opportunities for leisure activities) contributed to the variance of QOL in both countries, except for physical environment, which was significant in Brazil and not in Canada. Health satisfaction was the strongest contributor to QOL in both samples, and satisfaction with personal relationships was not significant in either country.

Activities of Daily Living↗
PubMed2003

Hospital waste operational procedures: a case study in Brazil.

This study analysed the hospital waste management practices and their implications to public health in the city of Belo Horizonte, south eastern Brazil. Belo Horizonte is a regional capital city located 300 miles from the famous city of Rio de Janeiro, Brazil. It is only 100 years old and is the first city planned in Brazil. It was originally planned for 300,000 people but, today, it is home to more than 2 million people. This study assessed the operational procedures at five hospitals (170 to 450 beds) with different medical specialties in order to analyse their major waste problems. This study also gathered data on different types of treatment and disposal procedures used by waste generators, which enabled an estimate on the amount of on-site and off-site waste generated.

Brazil↗
PubMedDate not supplied

Role of drug injection in the spread of HIV in Argentina and Brazil.

Drug injectors' have become the second largest HIV transmission category in Argentina and Brazil, as is the case in many pattern I countries, making up more than one-quarter of all AIDS cases reported by 1991. HIV seroprevalence data suggest that the expanding proportion of AIDS cases attributable to drug injection stems from an absolute increase in the number of AIDS cases among drug injectors, and is not merely reflective of a decline in the proportion of cases reported in other transmission categories. Results of a review of studies in Argentina and Brazil indicate that HIV seroprevalence is increasing rapidly, contrary to the situation in some pattern I countries in which HIV seroprevalence among drug injectors is either stably high or increasing only slightly. Also contrary to most pattern I countries, cocaine rather than heroin is the injected drug of choice in Argentina and Brazil. Given that injectors of cocaine are more likely to be HIV infected than are heroin injectors, differences in the type of drug injected between countries may have distinct epidemiological consequences on the spread of HIV.

Acquired Immunodeficiency Syndrome↗
PubMed2005

Public health policies as guides for local public policies: the experience of Sobral-Ceará, Brazil.

The accelerated urbanisation process that Brazil has gone through in the last 50 years has given rise to daunting challenges for public managers, especially in terms of local public policy management for the building of "healthy cities". In Sobral, a municipality of 173,000 inhabitants in Ceará in the North-eastern region of Brazil, a number of municipal policies were initiated beginning in 1997, many in partnership with the federal and state governments. They were inspired by the vision of a healthy and equitable city and were marked by strategic planning and the implementation of intersectoral projects. This article lays out some of the actions and their results, including an increase in the public supply of drinking water from 65% to 97% of households; an increase in sewage networks from 7% to 65%; an increase in public refuse collection from 42% to 90%; the expansion of green areas; the construction of nine kilometres of bicycle paths; the universalisation of integral health care through the Family Health Strategy through a network with specialised out-patient and hospital services; and a 148% increase in the number of children enrolled in primary school. These initiatives also resulted in the improvement of quality of life indicators, including a reduction in infant mortality from 61.4 to 19.0 per thousand live births, a drop in the mortality rate from traffic accidents from 33.40 per 100,000 inhabitants in 2001 to 15.25 in 2003; and a jump in literacy rates among children in the first cycle of primary school from 40 to 90.7%. In the present article, the authors describe some of the successful strategies and projects initiated between 1997 and 2003, and discuss how this experience could be reproduced in other communities across Brazil and around the world.

Adult↗
PubMed2002

Risk factors for hepatitis C virus infection among blood donors in southern Brazil: a case-control study.

BACKGROUND: In Brazil, it is estimated that between 2.5 and 4.9% of the general population present anti-hepatitis C virus (HCV) antibodies, which corresponds to as many as 3.9 to 7.6 million chronic carriers. Chronic liver disease is associated with HCV infection in 20% to 58% of the Brazilian patients. The objective of this case-control study was to investigate the risk factors for presence of anti-HCV antibody in blood donors in southern Brazil. METHODS: One hundred and seventy eight blood donors with two positive ELISA results for anti-HCV were cases, and 356 controls tested negative. A standardized questionnaire was used to collect data concerning demographic and socioeconomic aspects, history of previous hepatitis infection, social and sexual behaviors, and number of donations. Variables were grouped into sets of hierarchical categories. Cases and controls were compared using logistic regression, odds ratios, and 95% confidence intervals. The statistical significance of the associations was assessed through likelihood ratio tests based on a P value < 0.05. RESULTS: The prevalence of anti-HCV among blood donors was 1.1%. Most of the donors were white and males. In the multivariate analysis, independent predictors of anti-HCV positivity were: intravenous drug use, blood transfusion >10 years earlier, having had two to four sexually transmitted diseases, incarceration, tattooing, sex with a hepatitis B or C virus carrier or with intravenous drug users. CONCLUSION: Intravenous drug use, blood transfusion, and tattooing were the main risk factors for anti-HCV positivity among blood donors from southern Brazil, but sexual HCV transmission should also be considered.

Blood Donors↗
PubMed2006

Higher urine 1-hydroxy pyrene glucuronide (1-OHPG) is associated with tobacco smoke exposure and drinking maté in healthy subjects from Rio Grande do Sul, Brazil.

BACKGROUND: The highest rates of esophageal squamous cell carcinoma (ESCC) in Brazil occur in Rio Grande do Sul, the most southern state, which has incidence rates of 20.4/100,000/year for men and 6.5/100,000/year for women. Exposure to carcinogenic polycyclic aromatic hydrocarbons (PAHs) through tobacco smoke and other sources may increase the risk of ESCC. The aims of the current study were to investigate the degree and sources of PAH exposure of the inhabitants of this region of southern Brazil. METHODS: Two hundred healthy adults (half smokers, half non smokers, half male and half female) were recruited, given a standardized questionnaire, and asked to provide a urine sample for measurement of 1-hydroxypyrene glucuronide (1-OHPG), a PAH metabolite). Urine 1-OHPG concentrations were measured using immunoaffinity chromatography and synchronous fluorescence spectroscopy and urine cotinine was measured using a dipstick test. We examined factors associated with 1-OHPG concentration using Wilcoxon tests and multiple linear regression. RESULTS: Urine 1-hydroxypyrene glucuronide (1-OHPG) was successfully measured on 199 subjects. The median (interquartile range) of urine 1-OHPG in the 199 participants was 2.09 pmol/mL (0.51, 5.84). Tobacco smoke exposure and maté drinking were statistically significantly associated with higher urine 1-OHPG concentrations in the multivariate linear regression model. CONCLUSION: Tobacco smoke and maté both contribute to high levels of benzo[a]pyrene exposure in the people of southern Brazil. This high PAH exposure may contribute to the high rates of ESCC observed in this population. The increased urine 1-OHPG concentrations associated with maté suggest that contaminants, not just thermal injury, may help explain the increased risk of ESCC previously reported for maté consumption.

Alcohol Drinking↗
PubMed2006

Quality and effectiveness of different approaches to primary care delivery in Brazil.

BACKGROUND: Since 1994, Brazil has developed a primary care system based on multidisciplinary teams which include not only a physician and a nurse, but also 4-6 lay community health workers. This system now consists of 26,650 teams, covering 46% of the Brazilian population. Yet relatively few investigations have examined its effectiveness, especially in contrast with that of the traditional multi-specialty physician team approach it is replacing, or that of other existing family medicine approaches placing less emphasis on lay community health workers. Primary health care can be defined through its domains of access to first contact, continuity, coordination, comprehensiveness, community orientation and family orientation. These attributes can be ascertained via instruments such as the Primary Care Assessment Tool (PCATool), and correlated with the effectiveness of care. The objectives of our study are to validate the adult version of this instrument in Portuguese, identify the extent (quality) of primary care present in different models of primary care services, and correlate this extent with measures of process and outcomes in patients with diabetes, hypertension and coronary heart disease (CHD). METHODS/DESIGN: We are conducting a population-based cross-sectional study of primary care in the municipality of Porto Alegre. We will interview a random sample totaling 3000 adults residing in geographic areas covered by four distinct models of primary care of the Brazilian national health system or, alternatively, by one nationally prominent complementary health care service, as well as the physicians and nurses of the health teams of these services. Interviews query perceived quality of care (PCATool-Adult Version), patient satisfaction, and process indicators of management of diabetes, hypertension and known CHD. We are measuring blood pressure, anthropometrics and, in adults with known diabetes, glycated hemoglobin. DISCUSSION: We hope to contribute not only by validating the PCATool-Adult Version for use in Brazil, but also by furnishing ample data concerning the appropriate mix of health care professionals in the primary care team, a question of international import. Once validated, future use of this instrument should help direct advances aiming at improving the quality of primary care in Brazil.

Adult↗
PubMed2003

Genetic relatedness of Plasmodium falciparum isolates and the origin of allelic diversity at the merozoite surface protein-1 (MSP-1) locus in Brazil and Vietnam.

BACKGROUND: Despite the extensive polymorphism at the merozoite surface protein-1 (MSP-1) locus of Plasmodium falciparum, that encodes a major repetitive malaria vaccine candidate antigen, identical and nearly identical alleles frequently occur in sympatric parasites. Here we used microsatellite haplotyping to estimate the genetic distance between isolates carrying identical and nearly identical MSP-1 alleles. METHODS: We analyzed 28 isolates from hypoendemic areas in north-western Brazil, collected between 1985 and 1998, and 23 isolates obtained in mesoendemic southern Vietnam in 1996. MSP-1 alleles were characterized by combining PCR typing with allele-specific primers and partial DNA sequencing. The following single-copy microsatellite markers were typed : Polyalpha, TA42 (only for Brazilian samples), TA81, TA1, TA87, TA109 (only for Brazilian samples), 2490, ARAII, PfG377, PfPK2, and TA60. RESULTS: The low pair-wise average genetic distance between microsatellite haplotypes of isolates sharing identical MSP-1 alleles indicates that epidemic propagation of discrete parasite clones originated most identical MSP-1 alleles in parasite populations from Brazil and Vietnam. At least one epidemic clone propagating in Brazil remained relatively unchanged over more than one decade. Moreover, we found no evidence that rearrangements of MSP-1 repeats, putatively created by mitotic recombination events, generated new alleles within clonal lineages of parasites in either country. CONCLUSION: Identical MSP-1 alleles originated from co-ancestry in both populations, whereas nearly identical MSP-1 alleles have probably appeared independently in unrelated parasite lineages.

Alleles↗