Koko Otsuki

Molecular Epidemiology of Human T-Lymphotropic Virus Type II Infection in Amerindian and Urban Populations of the Amazon Region of Brazil

Molecular characterization of human T-cell lymphotropic virus II (HTLV-II) isolates in North America and Europe has shown the existence of two principal subtypes of the virus, HTLV-IIa and HTLV-IIb. Subsequent studies on HTLV-II isolates from Brazil have suggested the existence of a unique variant phylogenetically related to HTLV-IIa but phenotypically similar to HTLV-IIb with respect to the transactivatory protein, Tax. This variant has been designated HTLV-IIc. To better clarify the variability and distribution of HTLV-II in Brazil, the viruses present in two population groups from the Amazon region were tested for the presence of HTLV-II using serological and molecular assays. The groups consisted of blood donors from three Amerindian communities and of HIV-1/HTLV-II coinfected patients residing in Belém, an urban area. Nucleotide sequences and phylogenetic analysis confirmed the presence of HTLV-IIc subtype among Amerindian populations and, for the first time, the presence of the same virus among urban groups in Belém. The isolated occurrence of the HTLV-IIc subtype among Amerindian populations in the Amazon region could be attributed to (1) the different migratory pathways and founder effect, or (2) the local origin of a proto-HTLV-II carried by Amerindian ancestors who migrated to the Amazon circa 11,000 to 13,000 years ago. These results suggest that not only is HTLV-IIc unique to this region, but that its presence in urban areas of Brazil has resulted from admixture processes during the colonization of the country.

Serologic and molecular typing of human T-lymphotropic virus among blood donors in Maputo City, Mozambique

BACKGROUND: Screening for human T‐lymphotropic virus‐1/2 (HTLV‐1/2) infection is not performed in blood banks in Mozambique. The aim was to determine the prevalence of HTLV‐1/2 among blood donors of the Maputo Central Hospital Blood Bank and measure the coinfection rate of HTLV‐1/2 with human immunodeficiency virus (HIV), hepatitis B virus (HBV), and syphilis.

Molecular Analysis of 23 Exons of the CFTR Gene in Brazilian Patients Leads to the Finding of Rare Cystic Fibrosis Mutations

To define mutations present in 23 exons and flanking intronic sequences of the cystic fibrosis transmembrane conductance regulator (CFTR) gene in 95 patients from Rio de Janeiro, Brazil, we carried out single-strand conformation polymorphism analysis and automated direct sequencing. Mutation detection was achieved in 45% of the alleles presented, and complete genotyping (two mutated alleles) was accomplished in 34.7% of the patients. Twenty patients (21.1%) were found to carry only one mutation, whereas mutated alleles could not be observed in 42 patients (44.2%). Eleven mutations were found, of which four were characterized as rare mutations: P205S (1.05%), Y1092X (0.53%), S549R (0.53%), and S4X (0.53%). The DF508 mutation in this population sample showed a frequency of 28.42%. The low number of individuals (10 of 95; 10.5%) with compound heterozygous (DF508/non-DF508) genotypes could indicate the presence of another severe mutation leading to the premature death of these individuals. In 4 of the aforementioned 10 individuals with compound heterozygous genotypes, the D-7-2-1-2 (XV2c-KM19-IVS6a-TUB9-M470-T854) haplotype was defined.

Genetic Variability of HIV-1 Protease from Nigeria and Correlation with Protease Inhibitors Drug Resistance

In Nigeria, the most populous country in Africa, the characterization of HIV-1 strains has been limited. In this study we evaluated the genetic diversity of the protease coding region, one of the anti-retroviral therapy target, and investigated the presence of mutations related to resistance to HIV protease inhibitors. We analyzed samples collected during 1996 and all patients were anti-retroviral drug naı¨ves. Ten samples were evaluated by sequencing of the protease gene. The majority, 80%, were classified as subtype A and the two others were unclassified-divergent strains, something in between A and G subtypes. The gag region from these outliners were sequenced and the phylogenetic analysis classified them as subtype G. The protease amino acid consensus sequence of the Nigerian subtype A are in complete agreement with the consensus A differing from the USA subtype B consensus in 10 positions (L10V, I13V, K14R, I15V, K20I, M36I, R41K, P63L, H69K and L89M).The secondary substitutions associated with protease inhibitor resistance were observed in all Nigerian sequences at the positions L10V, M36I and L89M. The majority of sequence variation was concentrated in the interval between aminoacids 70–90 where the protease substrate binding region is located.

HTLV Type 1 Genetic Types among Native Descendants in Argentina

The province of San Salvador de Jujuy, located in the northwest of Argentina, is a highly endemic area for HTLV-1 infection and a foci of tropical spastic paraparesis/HTLV-1-associated myelopathy (HAM/TSP). Therefore, to better understand this, we carried out a genetic characterization of a large set of HTLV-1 strains (n = 65) of descendants of Amerindians from this region. The LTR and env regions were analyzed. The genetic analysis showed that all of these new HTLV-1 isolates from Argentina belong to the Transcontinental subgroup A of the HTLV-1a Cosmopolitan subtype, with the exception of three isolates that cluster within the Japanese subgroup B. Interestingly, the majority of the sequences from Jujuy province belonged to a distinct cluster within the Latin America Transcontinental subgroup, referred to here as the Jujuy subcluster, and were characterized by specific signatures in the LTR. Given that the samples analyzed in this study belong to the Amerindian population and the high prevalence of HTLV-1 in Jujuy in contrast to the low prevalence of this virus in the country, it could be that HTLV-1aA was spread in Argentina from the Amerindians to the cosmopolitan population. Moreover, this is the first report of an HTLV-1aB or Japanese subgroup in descendants of non-Japanese people in South America.

Presence of the cfxA gene in Bacteroides distasonis.

In this study we investigated the presence of the cfxA gene (encoding a class A beta-lactamase) in 73 strains of the Bacteroides fragilis group belonging to the species B. distasonis (34), B. vulgatus (14), B. thetaiotaomicron (8), B. merdae (6), B. caccae (9) and B. ovatus (2) isolated from human intestinal microflora of healthy children and adults. Employing specific primers to the cfxA gene, a 312-bp amplified fragment was obtained in 2 strains of B. vulgatus and 9 strains, the majority from children, of B. distasonis. The expression of this enzyme was analysed by determining the MICs to cefoxitin and cefotaxime and values varied from 2 to >256 microg/ml of both cefoxitin and cefotaxime. Sequence analysis of the amplicons corresponding to the cfxA gene from B. distasonis and B. vulgatus revealed identical sequences between these isolates and high similarity with other beta-lactamase genes of anaerobes such as cfxA of B. vulgatus (99%) and cfxA2 of Prevotella intermedia (99%), both sequences of which deposited in Genbank under accession numbers U38243 and AF118110, respectively. However, a fragment obtained from a B. distasonis strain (EC17-4) showed a unique RFLP profile and 87% nucleotide similarity with cfxA and cfxA2 genes. These results seem to suggest a dissemination of these resistance determinants among Bacteroides species.

High Prevalence of HTLV-1 Infection among Japanese Immigrants in Non-endemic Area of Brazil

Background Human T-lymphotropic virus type 1 (HTLV-1) has worldwide distribution and is considered endemic in many world regions, including southwestern Japan and Brazil. Japanese immigrants and their descendants have a high risk of acquiring this infection due to intense population exchange between Brazil and Japan. Objective This cross-sectional study aimed to estimate the prevalence of HTLV, analyze the main risk factors associated with this infection, identify the main circulating types and subtypes of HTLV in Japanese immigrants and descendants living in Campo Grande-MS (Middle-West Brazil), as well as analyze the phylogenetic relationship among isolates of HTLV. Study Design A total of 219 individuals were interviewed and submitted to blood collection. All collected blood samples were submitted for detection of anti-HTLV-1/2 using the immunoassay ELISA and confirmed by immunoblot method. The proviral DNA of the 14 samples HTLV- 1 positive were genotyped by nucleotide sequencing. Results The overall prevalence of HTLV-1 was 6.8% (IC 95%: 3,5-10,2). Descriptive analysis of behavioral risk factors showed statistical association between HTLV-1 and age greater than or equal to 45 years. The proviral DNA of HTLV-1 was detected in all HTLV-1 positive samples. Of these, 14 were sequenced and classified as Cosmopolitan subtype, and 50% (7/14) belonged to subgroup A (transcontinental) and 50% (7/14) to the subgroup B (Japanese). Conclusion The high prevalence of HTLV-1 found evidence of the importance of early diagnosis and counseling of individuals infected with HTLV-1 for the control and prevention of the spread of this infection among Japanese immigrants and their descendants in Central Brazil.

Prevalence of infection due to HTLV-1 in remnant quilombos in Central Brazil.

This study aimed to determine the prevalence of HTLV-1 infection among remnant black quilombo communities in Central Brazil. A total of 1,837 individuals were evaluated, among whom nine were HTLV-1/2 seropositive according to ELISA. All of them were positive for HTLV-1 by means of Western blot and/or PCR, thus resulting in a prevalence of 0.5% (95% CI: 0.2-1.0). The HTLV-1 infected individuals ranged in age from 11 to 82 years. The majority of them were females. Regarding risk characteristics, histories of breastfeeding, blood transfusion, multiple sexual partners and sexually transmitted diseases were reported by these individuals. The findings from this study indicate the importance of identifying HTLV-1 infected individuals, as a strategy for infection control and prevention in these remnant quilombos.This study aimed to determine the prevalence of HTLV-1 infection among remnant black quilombo communities in Central Brazil. A total of 1,837 individuals were evaluated, among whom nine were HTLV-1/2 seropositive according to ELISA. All of them were positive for HTLV-1 by means of Western blot and/or PCR, thus resulting in a prevalence of 0.5% (95% CI: 0.2-1.0). The HTLV-1 infected individuals ranged in age from 11 to 82 years. The majority of them were females. Regarding risk characteristics, histories of breastfeeding, blood transfusion, multiple sexual partners and sexually transmitted diseases were reported by these individuals. The findings from this study indicate the importance of identifying HTLV-1 infected individuals, as a strategy for infection control and prevention in these remnant quilombos.

Genetic Characterization of Human T-Cell Lymphotropic Virus Type 1 in Mozambique: Transcontinental Lineages Drive the HTLV-1 Endemic

Background Human T-Cell Lymphotropic Virus Type 1 (HTLV-1) is the etiological agent of adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). It has been estimated that 10–20 million people are infected worldwide, but no successful treatment is available. Recently, the epidemiology of this virus was addressed in blood donors from Maputo, showing rates from 0.9 to 1.2%. However, the origin and impact of HTLV endemic in this population is unknown. Objective To assess the HTLV-1 molecular epidemiology in Mozambique and to investigate their relationship with HTLV-1 lineages circulating worldwide. Methods Blood donors and HIV patients were screened for HTLV antibodies by using enzyme immunoassay, followed by Western Blot. PCR and sequencing of HTLV-1 LTR region were applied and genetic HTLV-1 subtypes were assigned by the neighbor-joining method. The mean genetic distance of Mozambican HTLV-1 lineages among the genetic clusters were determined. Human mitochondrial (mt) DNA analysis was performed and individuals classified in mtDNA haplogroups. Results LTR HTLV-1 analysis demonstrated that all isolates belong to the Transcontinental subgroup of the Cosmopolitan subtype. Mozambican HTLV-1 sequences had a high inter-strain genetic distance, reflecting in three major clusters. One cluster is associated with the South Africa sequences, one is related with Middle East and India strains and the third is a specific Mozambican cluster. Interestingly, 83.3% of HIV/HTLV-1 co-infection was observed in the Mozambican cluster. The human mtDNA haplotypes revealed that all belong to the African macrohaplogroup L with frequencies representatives of the country. Conclusions The Mozambican HTLV-1 genetic diversity detected in this study reveals that although the strains belong to the most prevalent and worldwide distributed Transcontinental subgroup of the Cosmopolitan subtype, there is a high HTLV diversity that could be correlated with at least 3 different HTLV-1 introductions in the country. The significant rate of HTLV-1a/HIV-1C co-infection, particularly in the Mozambican cluster, has important implications for the controls programs of both viruses.

Prevalence and genetic characterisation of HTLV-1 and 2 dual infections in patients with pulmonary tuberculosis in Central-West Brazil

Human T-cell lymphotropic virus (HTLV) may impact the clinical course of tuberculosis (TB). Both infections are highly endemic in Brazil. The aim of this study was to assess the prevalence of HTLV-1/2 in TB patients in Central-West Brazil and to perform a genetic characterisation of the respective isolates. Of the 402 patients, six (1.49%) were positive for anti-HTLV and five (1.24%; 95% confidence interval: 0.46-3.05) were infected with HTLV-1/2. Genetic characterisation demonstrated that the four HTLV-1 isolates belonged to the Transcontinental subgroup A of the Cosmopolitan subtype a and that the HTLV-2 isolate belonged to subtype a (HTLV-2a/c). The prevalence of HTLV infection observed in this study is higher than that observed in local blood donors and the HTLV-1 and 2 subtypes identified are consistent with those circulating in Brazil.