Maria Manuela da Fonseca Moura

The association of genetic markers and malaria infection in the Brazilian Western Amazonian region

Almost all individuals (182) belonging to an Amazonian riverine population (Portuchuelo, RO, Brazil) were investigated for ascertaining data on epidemiological aspects of malaria. Thirteen genetic blood polymorphisms were investigated (ABO, MNSs, Rh, Kell, and Duffy systems, haptoglobins, hemoglobins, and the enzymes glucose-6-phosphate dehydrogenase, glyoxalase, phosphoglucomutase, carbonic anhydrase, red cell acid phosphatase, and esterase D). The results indicated that the Duffy system is associated with susceptibility to malaria, as observed in other endemic areas. Moreover, suggestions also arose indicating that the EsD and Rh loci may be significantly associated with resistance to malaria. If statistical type II errors and sample stratification could be ruled out, hypotheses on the existence of a causal mechanism or an unknown closely linked locus involved in susceptibility to malaria infection may explain the present findings.

Nontuberculous mycobacteria in respiratory samples from patients with pulmonary tuberculosis in the state of Rondonia, Brazil

The main cause of pulmonary tuberculosis (TB) is infection with Mycobacterium tuberculosis (MTB). We aimed to evaluate the contribution of nontuberculous mycobacteria (NTM) to pulmonary disease in patients from the state of Rondônia using respiratory samples and epidemiological data from TB cases. Mycobacterium isolates were identified using a combination of conventional tests, polymerase chain reaction-based restriction enzyme analysis of hsp65 gene and hsp65 gene sequencing. Among the 1,812 cases suspected of having pulmonary TB, 444 yielded bacterial cultures, including 369 cases positive for MTB and 75 cases positive for NTM. Within the latter group, 14 species were identified as Mycobacterium abscessus, Mycobacterium avium, Mycobacterium fortuitum, Mycobacterium intracellulare, Mycobacterium gilvum, Mycobacterium gordonae, Mycobacterium asiaticum, Mycobacterium tusciae, Mycobacterium porcinum, Mycobacterium novocastrense, Mycobacterium simiae, Mycobacterium szulgai, Mycobacterium phlei and Mycobacterium holsaticum and 13 isolates could not be identified at the species level. The majority of NTM cases were observed in Porto Velho and the relative frequency of NTM compared with MTB was highest in Ji-Paraná. In approximately half of the TB subjects with NTM, a second sample containing NTM was obtained, confirming this as the disease-causing agent. The most frequently observed NTM species were M. abscessus and M. avium and because the former species is resistant to many antibiotics and displays unsatisfactory cure rates, the implementation of rapid identification of mycobacterium species is of considerable importance.

Genotyping of Mycobacterium leprae present on Ziehl-Neelsen-stained microscopic slides and in skin biopsy samples from leprosy patients in different geographic regions of Brazil

We analysed 16 variable number tandem repeats (VNTR) and three single-nucleotide polymorphisms (SNP) in Mycobacterium leprae present on 115 Ziehl-Neelsen (Z-N)-stained slides and in 51 skin biopsy samples derived from leprosy patients from Ceará (n = 23), Pernambuco (n = 41), Rio de Janeiro (n = 22) and Rondônia (RO) (n = 78). All skin biopsies yielded SNP-based genotypes, while 48 of the samples (94.1%) yielded complete VNTR genotypes. We evaluated two procedures for extracting M. leprae DNA from Z-N-stained slides: the first including Chelex and the other combining proteinase and sodium dodecyl sulfate. Of the 76 samples processed using the first procedure, 30.2% were positive for 16 or 15 VNTRs, whereas of the 39 samples processed using the second procedure, 28.2% yielded genotypes defined by at least 10 VNTRs. Combined VNTR and SNP analysis revealed large variability in genotypes, but a high prevalence of SNP genotype 4 in the Northeast Region of Brazil. Our observation of two samples from RO with an identical genotype and seven groups with similar genotypes, including four derived from residents of the same state or region, suggest a tendency to form groups according to the origin of the isolates. This study demonstrates the existence of geographically related M. leprae genotypes and that Z-N-stained slides are an alternative source for M. leprae genotyping.

Ocorrência de papilomavírus humano na cérvice uterina de mulheres da região ocidental da Amazônia Brasileira

A ocorrencia do papiloma virus humano (HPV) e um problema de saude publica, pois tem sido associado ao câncer. O objetivo da pesquisa foi identificar a ocorrencia de papilomavirus humano na cervice uterina de mulheres da regiao ocidental da Amazonia Brasileira. O estudo foi realizado na capital de Rondonia, Porto Velho. Foram identificados os tipos de HPV e resultados moleculares foram correlacionados com aqueles os testes colpocitologicos de amostras provenientes de 334 mulheres que realizaram exames preventivos no Sistema Unico de Saude. Obteve-se o material genetico viral do papilomavirus humano (DNA-HPV) e o fragmento de 450 pb da regiao conservada do gene L1 amplificado e submetido a analise do polimorfismo dos fragmentos de restricao (RFLP). Das 334 amostras analisadas, 31% foram confirmados com a presenca de material viral (DNA-HPV). Confirmou-se a existencia dos tipos: HPVS-16, 18, 33, 53 e 58, que identificam o grupo de alto risco oncogenico com 72% (74/103) de ocorrencia, bem como os HPVS-11, 42 e 44 pertencentes ao grupo de baixo risco oncogenico com 28% de ocorrencia. Os perfis recorrentes durante o desenvolvimento da analise foram do HPV-16 e -18 com 17% e 16%, respectivamente. Os resultados da pesquisa indicam que mais de 80% das amostras analisadas e que continham material viral nao apresentavam nenhuma alteracao celular no teste citologico, o que reforca a necessidade de se difundir o uso das tecnicas moleculares em diagnosticos convencionais.

Brazilian quilombos: A repository of Amerindian alleles

As a consequence of colonization of the Americas and decimation of the native population, an important portion of autochthonous genetic variation has been lost. However, some alleles have been incorporated into the growing populations of admixed mestizos. In this study, we evaluated the potential of African‐derived communities in Brazil to be repositories of Amerindian alleles and, by extension, a source of information on American prehistory.

Y chromosome comparative analysis of Rondônia with other Brazilian populations.

In the present study, a Brazilian population, located in the Rondônia state, was genetically characterized for a set of Y chromosome specific STRs included in the Applied Biosystems kit (AmpFℓSTR®Yfiler™), which allows the simultaneous amplification of 16 markers: DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385a/b, DYS438, DYS439, DYS437, DYS448, DYS456, DYS458, DYS635 and GATA H4. The studied population from Rondônia state, in the North of Brazil, included individuals with admixed Native American, African and European ancestry. When comparing Rondônia with other Brazilian populations no significant genetic distances were found. In the comparison with other worldwide populations, although a predominant male European influence could be detected, there were significant differences with some populations from Central and South America and Africa.

A Major Genetic Mechanism Involved in Resistance to Malaria in Western Amazonia

Abstract Malaria, the world’s most important cause of infectious morbidity and mortality, has a widespread geographical distribution in the tropical region, while its endemicity is very heterogeneous. The Amazonia region, due mainly to its relatively low demographic index, is characterized as an hypo-endemic region. A population of 182 individuals, living in Portuchuelo, State of Rondônia, Brazil, right bank of the Madeira river (8° 37′ S, 63° 49′ W) was surveyed, in order to ascertain data on the epidemiological aspects of malaria and some other infectious diseases. Two main phenotypes involved with Plasmodiuminfection were studied: a) the presence of symptomless infection i.e., presence of Plasmodium, diagnosed either by traditional thick smear or by PCR amplification of Plasmodium ribosomal DNA in blood samples; b) the reported number of previous malaria episodes. Segregation analysis was applied to both phenotypes. There were no evidences of any type of familial mechanisms acting on the distribution of the symptomless phenotype in this population, since there was no significant familial aggregation. As for the number of malarial episodes, this phenotype showed clear signs of Mendelian inheritance. The most parsimonious model includes a co-dominant major gene with frequency of q= 0.15 and a small multifactorial component (H= 0.08). Due to this frequency and the mode of inheritance, this finding seemed to be independent of the Hb, Fy or G-6- PD polymorphisms.