Prevalence of abnormal hemoglobins in newborns in Natal, Rio Grande do Norte, Brazil

Hemoglobinopathies are among the most prevalent hereditary diseases in humans. Studies in different areas of Brazil have identified the prevalence of S and C abnormal hemoglobins. The study analyzed 1,940 cord blood samples of newborns from maternity hospitals in Natal, Rio Grande do Norte State, to investigate the prevalence of abnormal hemoglobins. All samples were submitted to cellulose acetate electrophoresis using a Tris-EDTA-borate buffer at pH 8.5. Electrophoresis in agar gel pH 6.2 was performed on samples presenting abnormal hemoglobin. Some 37 (1.91%) of the newborns presented hemoglobinopathies, as follows: 29 (1.50%) sickle cell trait (Hb FAS), 6 (0.31%) heterozygous Hb C (Hb FAC), one (0.05%) homozygous Hb S (Hb FS), and one (0.05%) Hb Barts suggestive of alpha thalassemia. The results show the need to implement screening for hemoglobinopathies in the neonatal population.     

海南省琼中县3392名中学生地中海贫血血细胞参数与基因检测结果分析

目的研究海南省琼中黎族苗族自治县地中海贫血血细胞参数及基因检测结果,为有效预防和监控该地区地中海贫血提供依据。 方法采集海南省琼中县3392名中学生外周血进行血常规、血红蛋白电泳和脆性试验筛查,阳性样本行基因检测,对基因类型、突变频率及血细胞参数等情况进行分析。 结果3392名受检者中,初筛阳性1439例,经基因检测确认阳性1049例,其中单纯α地贫784例(74.7%);单纯β地贫143例(13.6%);α、β复合型地贫为122例(11.6%)。α地贫以αα/-α^3.7(33.4%)、αα/-α^4.2(31.3%)为主,β地贫中β^CD41-42/β^N(76.2%)突变最常见;除HbA和女性血红蛋白外,其它各血细胞参数在健康组、α地贫、β地贫3组间均存在统计学差异(P<0.05);血常规、血红蛋白成分分析联合初筛效果最佳。 结论琼中县α、β地贫携带率及基因型分布符合海南地区的基本特点,各类地贫血细胞参数与基因相关性、最适初筛方案均可为该地区的地贫防控工作提供依据。     

深圳市南山区2 898例地中海贫血基因检测结果分析

目的 研究深圳市南山区地中海贫血基因型和分布特征,探讨检测该病的优化方案。方法 以2017年3月 - 2018年3月在某院进行地中海贫血检测的2 898例就诊者为研究对象,采用跨越断裂点PCR法、反向斑点杂交法和Sanger测序进行基因分析。结果 2 898例受检者中检出地中海贫血基因变异804例,检出率达27.74%。常规地贫基因检测方法检出α-地中海贫血545例,--SEA/αα检出率（11.84%）最高,其次是-α3.7/αα（3.00%）和-α4.2/αα（1.83%）;β-地中海贫血225例,CD41-42（-TTCT）杂合突变和IVS－Ⅱ－654（C＞T）杂合突变为2种检出率最高的突变类型,检出率为3.00%和2.52%;αβ复合地中海贫血30例;Sanger测序分析检出4例少见杂合变异,分别为:HBA1基因上CD5 (GCC＞ACC );HBB基因CD37G＞A、IVS-Ⅱ-806(G＞C)、IVS-Ⅱ-81C＞T。结论 深圳市南山区地中海贫血发病率较高,基因型与广东省其他地区基本一致。当血液学表型和常规基因检测不相符时,应进行基因测序排除罕见型地中海贫血或异常血红蛋白变异。     

柳州市城镇人群α和β地中海贫血的发生率调查和基因型鉴定

目的 调查广西柳州市城镇人口中α和β地中海贫血（地贫）的发生率和基因突变类型及其构成比。方法 以整群抽样收集1028份其父母双方或一方为柳州市户口的新生儿脐带血及1312份柳州市户口的婚检育龄成人的外周静脉血，分别进行α地贫和β地贫调查；所有样品均进行红细胞（RBC）参数和血红蛋白（Hb)电泳分析，以巴特血红蛋白（Hb Bart's)阳性者为α地贫，平均红细胞体积（MCV＜85fl和HbA2≥4．0％为β地贫阳性表型指标。采用基于PCR的基因分析方法进行α和β地贫及β地贫复合α地贫样品的确诊，对α和β地贫表型阳性而未查出基因者，以家系成员的表型分析诊断。结果 1028份脐带血样品检出α基因携带者112例（包括3例双重杂合子），α地贫基因携带率11．19％，共检出含5种α地贫的等位基因，其构成比依次为37．4％（－－^SEA),31.3%(-α^3.7),17.4%(-α^4.2),12.1%(α^CSα)和0．9％（α^QSα)。1312份成人外周静脉血样品共发现β地贫携带者89例，基因携带率为6．78％。其中有14例伴有胎儿血红蛋白（HbF)增高，检出率1．07％。在89例β地贫阳性样品中，有16例（占18％）为β地贫复合α地贫双重杂合子，共发现9种不同的基因型，检出率为1．22％。该地区3种最常见的基因－βCD41－42（－CTTT）移码突变，βCD17（T－A）无义突变和β－28（A－G）转录突变占突变基因的90％。结论 α和β地中海贫血在柳州地区的发生率很高。     

广西梧州地区地中海贫血儿童地贫基因型构成分析

目的 了解梧州地区地中海贫血高风险儿童地中海贫血的检出率及基因型构成情况,为制定防治策略、降低发病率提供参考.方法 应用跨跃断裂点PCR和PCR结合反向斑点杂交技术对2010—2018年的梧州地区地中海贫血高风险患儿进行α地中海贫血4种缺失型、3种点突变以及β地中海贫血的17种点突变进行检测和构成分析.结果 地中海贫血...     

Prevalence of hemoglobin S in the State of Paraná, Brazil, based on neonatal screening

The Brazilian Ministry of Health created the National Neonatal Screening Program under ruling no. 822/2001, including neonatal screening for hemoglobinopathies. In the State of Paraná, neonatal screening is conducted by the Ecumenical Foundation for the Protection of the Handicapped. The prevalence rates were determined for homozygous and heterozygous hemoglobin S and Sbeta-thalassemia. Blood samples drawn on filter paper were examined by isoelectric focusing (IEF) and high-performance liquid chromatography (HPLC). From January 2002 to December 2004, 548,810 newborns were screened, with the detection of 21 with FS, two FSA/FS, and four FSA. After confirmatory tests at six months of age, 12 were defined as sickle-cell anemia, or a prevalence of 2.2:100,000 newborns; Sbeta-thalassemia was confirmed in 15 (2.7:100,000 newborns); and 8,321 newborns were diagnosed as heterozygous HbS (1,500:100,000 newborns). HbS prevalence in Paraná (in southern Brazil) is lower than in the Central-West, North, and Northeast of the country. Ethnic origin of the population, fetal deaths, and non-random procreation may contribute to the relatively low number of homozygous individuals in the State. Sbeta-thalassemia interaction suggests the presence of Euro-Mediterranean peoples in this population's miscegenation.     

新生儿脐血α地中海贫血筛查研究(附204例报告)

本文总结了1994年4月～12月在我院产科分娩的204例新生儿,进行脐血血红蛋白电泳筛查,发现α地中海贫血标准型基因携带者19例,静止型基因携带者5例,其发生率为11.7%.随访3～6个月复查血红蛋白电泳均正常.提示脐血筛查α地中海贫血及时准确,有利遗传咨询指导婚姻及优生优育.     

黄石地区30554例新生儿地中海贫血筛查的基因型和临床表型分析

目的 了解地中海贫血(地贫)基因在黄石地区的分布情况及不同基因型的临床表现,为该病的筛查预防提供依据。方法 采用毛细管电泳进行地中海贫血初筛,筛查阳性者召回进行地中海贫血基因和血常规检测。结果 2018年1—12月黄石地区活产31 140人,新生儿疾病筛查30 554人,筛查率为98.12%,地贫阳性检出率为1.79%(546/30 554)。α地贫占73.44%(401/546),基因型包含--^SEA/αα(54.11%)、-α^3.7/αα(37.66%)、-α^4.2/αα(6.48%)等,临床表型为轻型221例,静止型177例,中间型3例。β地贫占26.01%(142/546),检出IVS-2-654(50.7%)、CD41-42(19.72%)、CD17(8.45%)等13种突变类型,临床表型为轻型133例,中间型9例。αβ复合型地贫3例,2例东南亚缺失型α地贫可能合并有香港型HKαα。人群中地贫基因携带者贫血发生率为27.29%,轻度贫血占71.81%;α地贫携带者贫血发生率为21.95%,轻度贫血占78.41%;β地贫携带者贫血发生率为42.25%,轻度贫血占63.33%。结论 黄石地区人群地贫阳性以α地贫为主,α地贫以--^SEA/αα最常见,β地贫以IVS-2-654最常见,αβ复合型地贫少见,临床表型均以静止型和轻型为主。在地贫基因携带者中β地贫发生概率高于α地贫。通过开展地中海贫血的筛查,为本地区防控地中海贫血预防出生缺陷提供了参考依据。     

桂林市城镇育龄人群地中海贫血现况调查

目的 调查桂林市城镇育龄人群地中海贫血(地贫)的现况.方法 用红细胞平均容积(MCV)和血红蛋白电泳法对所有调查对象进行地贫筛查,对筛查出疑为α地贫或β地贫标本进一步采用PCR结合反向点杂交法(ROB)进行基因检测,以检出地贫基因来确诊.结果 在1580例受检者中,确定α地贫基因型的有79例,检出率为5.00%,α贫在男女性中检出率分别为5.32%、4.68%,差异无统计学意义(X2=3.04,X2＜X0.05(1)=3.84,P＞0.05);确定β地贫基因型的有114例,检出率为7.22%,β地贫在男女性中检出率分别为7.85%、6.58%,差异无统计学意义(X2=0.95,X2＜X0.05(1)=3.84,P＞0.05);总的地贫检出率为12.22%(193/1580).α地贫共检出10种基因型,以轻型--SEA/αα为主,检出率为3.54%;静止型以-α3.7/αα居多,轻型以--SEA/αα居多,中间型以--SEA/-αCS居多;其构成比分别为7.59%、70.88%、2.53%;B地贫共检出7种基因型,以CD41-42(-TTCT)居多,检出率为3.16%,其中最常见的3种基因型CD41-42(-TTCT)、CDl7(A→T)和IVS-Ⅱ-654(C→T),构成占突变基因的87.71%;β、α复合型地贫检出率为0.63%.结论 桂林市城镇育龄人群地贫检出率较高.     

Neonatal screening for hemoglobinopathies: a one-year experience in the public health system in Rio Grande do Sul State, Brazil

Hemoglobinopathies are the most common inherited disorders in humans; the most frequent are hemoglobins S and C (Hb S and Hb C). Studies in Brazil show the high prevalence of Hb S and Hb C heterozygotes, indicating the need for diagnosis to allow medical care and suitable genetic counseling. This study evaluates the prevalence of hemoglobin patterns in different areas of Rio Grande do Sul State, Brazil, using neonatal data from the public health system. Blood samples from 117,320 newborns, obtained by heel stick, and 2,389 blood samples from parents of newborns, obtained by venopuncture, were submitted to IEF and HPLC. Among the newborns, 1,629 (1.4%) showed abnormal hemoglobin patterns: 1,342 FAS; 225 FAC; 45 FAD; 2 FSC; 1 FS and 26 variant hemoglobin heterozygotes. We conclude that the methods used are able to identify a broad variety of hemoglobin patterns with high specificity and sensitivity. The information is of paramount importance for transmitting knowledge in the public health field, besides facilitating planning and resource allocation.     

Screening for hemoglobinopathies in blood donors from Caxias do Sul, Rio Grande do Sul, Brazil: prevalence in an Italian colony

The high prevalence of beta thalassemia among Italians and their participation in the ethnic formation of Caxias do Sul, Rio Grande do Sul State, Brazil, and neighboring cities prompted us to investigate hemoglobinopathies in 608 blood donors at the Caxias do Sul Regional Blood Center. Despite the ethnic influence, abnormal hemoglobin levels were found in only 1.81% of the donors (0.16% Hb AC, 0.99% Hb AS, and 0.66% Hb AH), similar to the levels observed in a study on qualitative disorders conducted in the rural area of Rio Grande do Sul. In our setting, the most commonly used screening tests for thalassemia, combined with DNA sequencing, were unable to detect quantitative hemoglobin synthesis disorders. This may be attributable to still-unknown genetic disorders, technical limitations, or simply to miscegenation.     

C677T polymorphism of the MTHFR gene and variant hemoglobins: a study in newborns from Salvador, Bahia, Brazil

The C677T polymorphism in the methylenetetrahydrofolate reductase gene (MTHFR) is associated with an increase in total homocysteine serum levels (tHcy), described as a risk factor for cardiovascular disease. Eight hundred forty-three neonates from two different maternity hospitals, one public and another private, in Salvador, Bahia, Brazil were screened for this polymorphism by PCR and RFLP. The T-allele frequency in the total sample was 0.23, and the prevalence rates of heterozygous and homozygous carriers were 36.2% and 5.3%, respectively. The T-allele frequency differed and the T/T genotype was more prevalent at the private maternity hospital. The hemoglobin (Hb) profile was investigated by HPLC in 763 newborns. The frequency of variant Hb was higher at the public than at the private maternity hospital. The association of the C677T polymorphism and the Hb profile was investigated in 683 newborns, showing a relatively high frequency of variant Hbs and the T allele. These data could provide an important basis for further studies focusing on potential risks of vaso-occlusive events in these individuals.     

广西南宁市农村育龄人群地中海贫血筛查及基因型和血液学参数分析

目的调查南宁市农村育龄人群地中海贫血（地贫）基因携带率和基因型，分析地贫血液学参数变化特点。方法以血红蛋白（Hb）自动分析仪．VARIANT（HPLC）和Cell Dyn1700全自动血细胞分析仪检测育龄青年2044例，其中430例（地贫筛查中随机选择的75对夫妇以及血细胞分析提示夫妇双方或一方为地贫表型阳性的育龄夫妇140对）同步进行地贫基因分析。结果检出8地贫163例，8地贫基因携带率7．97％，检出HbH病13例，Hb Manitoba2例，HbJ 2例，HbQ1例。α地贫2基冈型以-α^3.7／αα、-α^CS／αα和-α^WS／αα居多，α地贫1以—^SEA／αα为主，β地贫杂合子以41-42为主，α、β复合型地贫有较高的检出率。所有HbH病和β地贫平均红细胞体积（MCV）和平均红细胞Hb含量（MCH）均降低，86例α地贫1中除1例MCH正常外均降低，而66例α地贫2中17例MCV和MCH均正常，69例β地贫杂合子中有32例HbF增高，但没有一例只有HbF增高而HbA2不增高，α、β复合型地贫主要呈现β地贫血液学特点。结论南宁市农村育龄人群地贫基因携带率高，-α^WS／αα和-α^CS／αα基因型α地贫2较多，高发区MCV和MCH降低应疑为地贫。     

The frequency of anaemia,iron deficiency,hemoglobin S and beta thalassemia in the South of Turkey

A survey on the prevalence of anemia, iron deficiency, and hemoglobinopathies (Hb S and beta thalassemia) was carried out in an ethnically mixed and carefully registered population of 45,000 living in an area in the Southern Turkey. A total of 1223 subjects (representing the population with respect to sex and age group) were surveyed. The rate of anemia was found to be 16.9% overall with a highest prevalence of 18.3% in the children (0–2 ages) and 16.3% in the 14+ age group. The prevalence of iron deficiency using low transferrin saturation as criteria was found to be 17.2% overall, being 48.0% in the infant group, 19.6% in the children, and 14.7% in the 14+ age group. The rate of Hb S using the sickling test was found to be 3.9% in the entire population without separating for ethnic groups. It was more prevalent (9.6%) in the Arabic speaking and not found at all in the Kurdish speaking people. The rate of beta thalassemia with a high HbA₂ was 3.4% overall and highest (7.1%) in the Kurdish speaking people.     

Justifications for formula supplementation in low-risk newborns at a Baby-Friendly Hospital

The Baby-Friendly Hospital Initiative recommends not giving newborn infants any food or drink other than breast milk unless medically indicated. This study investigated the prevalence and alleged reasons for giving formula supplementation to rooming-in newborns at a Baby-Friendly Hospital. Participants were 300 formula-supplemented, exclusively rooming-in newborns at a Baby-Friendly Hospital in Rio de Janeiro, Brazil. Reasons for formula supplementation were classified as acceptable or unacceptable in accordance with the WHO/UNICEF Baby-Friendly Hospital Initiative guidelines. A supplementation prevalence of 33.3% was found. The main allegations were: hypogalactia/ agalactia (36.8%), conditions involving risk of hypoglicemia (21.1%), cesarean section (7.9%), stomatognathic system-related conditions (7.4%), maternal conditions (6.3%), and absence of maternal HIV serology (4.5%). Cesarean section was associated with a higher risk of supplementation (RP = 2.1; 95%CI: 1.77-2.55) as compared to vaginal delivery. Supplementation prevalence was high, and only 9% of the allegations were justified.     

Associated factors and consequences of late preterm births: results from the 2004 Pelotas birth cohort

Although neonatal and infant mortality rates have fallen in recent decades in Brazil, the prevalence of preterm deliveries has increased in certain regions, especially in the number of late preterm births. This study was planned to investigate: (1) maternal antenatal characteristics associated with late preterm births and (2) the consequences of late preterm birth on infant health in the neonatal period and until age 3 months. A population-based birth cohort was enrolled in Pelotas, Southern Brazil, in 2004. Mothers were interviewed and the gestational age of newborns was estimated through last menstrual period, ultrasound and Dubowitz's method. Preterm births between 34 and 36 completed weeks of gestational age were classified as late preterm births. Only singleton live births from mothers living in the urban area of Pelotas were investigated. Three months after birth, mothers were interviewed at home regarding breast feeding, morbidity and hospital admissions. All deaths occurring in the first year of life were recorded. A total of 447 newborns (10.8%) were late preterms. Associations were observed with maternal age <20 years (prevalence ratio [PR] 1.3 [95% CI 1.1, 1.6]), absence of antenatal care (PR 2.4 [1.4, 4.2]) or less than seven prenatal care visits, arterial hypertension (PR 1.3 [1.0, 1.5]), and preterm labour (PR 1.6 [1.3, 1.9]). Compared with term births, late preterm births showed increased risk of depression at birth (Relative risk [RR] 1.7 [1.3, 2.2]), perinatal morbidity (RR 2.8 [2.3, 3.5]), and absence of breast feeding in the first hours after birth (PR 0.9 [0.8, 0.9]). RRs for neonatal and infant mortality were, respectively, 5.1 [1.7, 14.9] and 2.1 [1.0, 4.6] times higher than that observed among term newborns. In conclusion, in our setting, the prevention of all preterm births must be a priority, regardless of whether early or late.     

Anaemia in pregnant Ghanaian women: importance of malaria, iron deficiency, and haemoglobinopathies

In sub-Saharan Africa, anaemia in pregnancy results from multiple causes including malaria, iron deficiency and haemoglobinopathies. In a cross-sectional study among 530 pregnant women in Ghana in November-December 1998, red blood cell indices were analysed with respect to malaria, serum concentrations of ferritin and C-reactive protein (CRP), and the haemoglobin and alpha-globin genotypes. Anaemia (haemoglobin [Hb] < 11 g/dL) was found in 54% of the women; 63% harboured malaria parasites at predominantly low numbers. Ferritin levels were considerably influenced by malaria and inflammatory processes (CRP > 0.6 mg/dL). Depending on the definition applied, the prevalence of iron deficiency ranged between 5% and 46%. The HbAS trait was observed in 14%, HbAC and elevated HbF in 7% each, and sickle cell disease in 1%. Heterozygous beta-thalassaemia was present in 1% of the women and alpha(+)-thalassaemia in 33% (29% heterozygous, 4% homozygous). Women with HbAS had higher malaria parasite densities than those with HbAA. In individuals with highly elevated HbF (> 10%), parasitaemia occurred in 27% only. Low gravidity, second trimester of pregnancy, malaria, raised CRP levels, and homozygous alpha(+)-thalassaemia were independent risk factors for anaemia in multivariate analysis. alpha(+)-Thalassaemia, however, was associated with a lesser degree of malarial anaemia when compared to non-thalassaemic women. Iron deficiency appears not to be a major health problem in this population. Haemoglobinopathies are common but, except for homozygous alpha(+)-thalassaemia, do not substantially contribute to anaemia in pregnancy. alpha(+)-Thalassaemia ameliorates malarial anaemia in pregnant women.     

Association between gestational night blindness and serum retinol in mother/newborn pairs in the city of Rio de Janeiro, Brazil

OBJECTIVE: Gestational night blindness (XN) is associated with increased risk of reproductive morbidity and mortality. This study investigated the prevalence of gestational XN among postpartum women treated in a public maternity hospital in the city of Rio de Janeiro, Brazil and evaluated its association with maternal and neonatal (cord blood) serum retinol concentrations. METHODS: XN was evaluated retrospectively, using an interview according to guidelines of the World Health Organization, in 222 postpartum women (< or = 6 h after delivery) after singleton births who had low obstetric risk. Serum retinol concentrations were measured according to the modified Bessey method, with a cutoff point lower than 1.05 micromol/L for inadequate serum retinol concentration. RESULTS: Prevalence of gestational XN was 18%, and inadequate maternal and cord blood serum retinol concentrations were found in 24.4% and 45.5% of samples, respectively. The results associated gestational XN with inadequate maternal serum retinol concentration (P = 0.000), and an association was observed between maternal and neonatal serum retinol concentrations (P = 0.000). A poor association was observed between maternal XN and serum levels of retinol in newborn children (P = 0.06). CONCLUSIONS: The results suggest that prevalence of gestational XN and inadequate serum retinol concentration among postpartum women and newborns is a concern, calling attention to the need for studies in other parts of Brazil. In addition, the risk of inadequate serum retinol in newborns was significantly higher among infants of postpartum women with serum retinol levels below 1.05 micromol/L. Gestational XN was associated with inadequate levels of maternal serum retinol, and the results suggest a poor relation between maternal XN and vitamin A nutritional status of newborns.     

探讨地中海贫血筛查方案及南宁市农村育龄人群基因型分析

目的探讨在地中海贫血（简称地贫）高发区地贫筛查实验的最佳组合，研究最理想且能够推广的筛查路线及分析当地地贫基因型分布情况。方法采用红细胞脆性定性试验、红细胞脆性一管法定量试验、法国MgthicL18全自动血细胞分析仪、法国Sebia公司全自动电泳仪检测育龄人群4050例，Gap—PCR技术和反向斑点杂交技术检测育龄人群1000例，对检测结果进行分析。结果红细胞平均体积（MCV）法、红细胞脆性定性试验、红细胞脆性一管法定量试验筛查地贫灵敏度及特异度分别为90．32％、72．22％、72．38％及85．14％、82．43％、82．16％。其中MCV法在筛查8地贫、HbH病的灵敏度达100％，筛查α地贫，的灵敏度达99．51％。电泳对8地贫、HbH病、Hb Constant Spring（HbCS）的诊断与基因检测相符。β地贫杂合子中41—42、17杂合子分别占38．27％、24．49％；-^SEA／αα基因型占α地贫1的95．63％；-α^3.7／αα、-α^4.2／αα、α^CS／（1（1基因型分别占α地贫2的36．78％、28．74％、22．99％；α、β双重杂合子占筛查检出的β地贫的17．66％。结论MCV法结合Sebia琼脂糖凝胶电泳筛查地贫效果理想，MCV法初筛，操作简单、易于掌握，适合在基层推广。南宁市农村8地贫杂合子基因突变以41—42、17为主；α地贫则以-^SEA／αα、-α^3.7／α、-α^4.2/αα、-α^CS／αα基因型为主。α、β双重杂合子检出率高。     

Seroprevalence of human parvovirus B19 in a suburban population in São Paulo, Brazil

OBJECTIVE: To analyze the prevalence of IgG antibodies to human parvovirus B19. METHODS: Cross-sectional study in a suburban community in S?o Paulo, Southeastern Brazil, between November 1990 and January 1991. Randomly selected (N=435) representative samples of sera were collected from healthy children older than 15 days old and adults up to 40 years old. IgG antibodies were detected using ELISA. RESULTS: High prevalence of IgG antibodies to B19 parvovirus was found in 87% of newborns. The prevalence of maternally derived IgG antibodies exponentially plunged up to the 19th month of age. Low prevalence of antibodies was found in the first 4 years of life, increasing up to 72% in those aged 31-40 years. It was estimated that the average age of first infection in this population is 21 +/- 7 years old and the optimal age for vaccination with a hypothetical vaccine would be 1 year of age. CONCLUSIONS: Parvovirus B19 IgG antibody prevalence was high in newborns and those aged 31-40 years. The analysis by age groups showed a pattern similar to that found in previous studies, i.e., low prevalence of infection in children that increases with age.