An overview of Zika virus genotypes and their infectivity

ABSTRACT Zika virus (ZIKV) is an enveloped, single-stranded RNA arbovirus belonging to the genus Flavivirus. It was first isolated from a sentinel monkey in Uganda in 1947. More recently, ZIKV has undergone rapid geographic expansion and has been responsible for outbreaks in Southeast Asia, the Pacific Islands, and America. In this review, we have highlighted the influence of viral genetic variants on ZIKV pathogenesis. Two major ZIKV genotypes (African and Asian) have been identified. The Asian genotype is subdivided into Southwest Asia, Pacific Island, and American strains, and is responsible for most outbreaks. Non-synonymous mutations in ZIKV proteins C, prM, E, NS1, NS2A, NS2B, NS3, and NS4B were found to have a higher prevalence and association with virulent strains of the Asian genotype. Consequently, the Asian genotype appears to have acquired higher cellular permissiveness, tissue persistence, and viral tropism in human neural cells. Therefore, mutations in specific coding regions of the Asian genotype may enhance ZIKV infectivity. Considering that mutations in the genomes of emerging viruses may lead to new virulent variants in humans, there is a potential for the re-emergence of new ZIKV cases in the future.

HIV-1 mother-to-child transmission in Brazil (1994-2016): a time series modeling

Abstract HIV-1 mother-to-child transmission (HIV-1 MTCT), is an important cause of children mortality worldwide. Brazil has been traditionally praised by its HIV/Aids program, which provides free-of-charge care for people living with HIV-1. Using public epidemiology and demographic databases, we aimed at modeling HIV-1 MTCT prevalence in Brazil through the years (1994-2016) and elaborate a statistical model for forecasting, contributing to HIV-1 epidemiologic surveillance and healthcare decision-making. We downloaded sets of live births and mothers' data alongside HIV-1 cases notification in children one year old or less. Through time series modeling, we estimated prevalence along the years in Brazil, and observed a remarkable decrease of HIV-1 MTCT between 1994 (10 cases per 100,000 live births) and 2016 (five cases per 100,000 live births), a reduction of 50%. Using our model, we elaborated a prognosis for each Brazilian state to help HIV-1 surveillance decision making, indicating which states are in theory in risk of experiencing a rise in HIV-1 MTCT prevalence. Ten states had good (37%), nine had mild (33%), and eight had poor prognostics (30%). Stratifying the prognostics by Brazilian region, we observed that the Northeast region had more states with poor prognosis, followed by North and Midwest, Southeast and South with one state of poor prognosis each. Brazil undoubtedly advanced in the fight against HIV-1 MTCT in the past two decades. We hope our model will help indicating where HIV-1 MTCT prevalence may rise in the future and support government decision makers regarding HIV-1 surveillance and prevention.

Antiretroviral therapy immunologic non-response in a Brazilian population: association study using pharmaco- and immunogenetic markers

ABSTRACT Background: Antiretroviral therapy (ART) saved millions from HIV-1 infection and AIDS, but some patients do not experience adequate CD4+ T cells gain despite achieving viral suppression. The genetic component of this condition is not yet completely elucidated. Objective: To identify predictive genetic markers of immune response to ART. Methods: Case-control study. Out of 176 HIV-infected patients recruited in the city of Recife, Northeast Brazil, 67 patients with no immunologic response were the cases and the remaining 109 patients who responded were the controls. A set of 94 selected single nucleotide polymorphisms (SNPs) involved in antiretroviral drugs pharmacodynamic pathways and immune system homeostasis were genotyped, while the remaining 48 were ancestry informative markers (AIMs) for controlling for eventual hidden population structure. Results: Male patients were overrepresented in non-responder group (p = 0.01). Non-responders also started with lower absolute CD4+ T cell counts (p < 0.001). We found five SNPs significantly associated with the outcome, being three more frequent in non-responders than responders: rs2243250 (IL4) A allele (p = 0.04), rs1128503 (ABCB1) A allele (p = 0.03) and rs707265 (CYP2B6) A allele (p = 0.02), whereas the other two were less frequent in non-responders: rs2069762 (IL2) C allele (p = 0.004) and rs4646437 (CYP3A4) A allele (p = 0.04). Conclusion: Some significant univariate associations remained independently associated at multivariate survival analysis modeling, such as pre-treatment CD4+ T cells counts, IL2 and ABCB1 genotypes, and use of protease inhibitors, yielding a predictive model for the probability for immune response. More studies are needed to unravel the genetic basis of ART immunological non-response.

Prevalence of Guillain-Barré syndrome among Zika virus infected cases: a systematic review and meta-analysis

ABSTRACT Zika virus (ZIKV) is an emergent flavivirus transmitted mainly through Aedes spp. mosquitoes that is posing challenge to healthcare services in countries experiencing an outbreak. Usually ZIKV infection is mild, but in some cases it has been reported to progress into neurological diseases such as microcephaly in infants and Guillain-Barré syndrome (GBS) in adults. GBS is a debilitating autoimmune disorder that affects peripheral nerves. Since ZIKV caused massive outbreaks in South America in the past few years, we aimed to systematically review the literature and perform a meta-analysis to estimate the prevalence of GBS among ZIKV-infected individuals. We searched PubMed and Cochrane databases and selected three studies for a meta-analysis. We estimated the prevalence of ZIKV-associated GBS to be 1.23% (95% CI = 1.17-1.29%). Limitations include paucity of data regarding previous flavivirus infections and ZIKV-infection confirmation issues. Our estimate seems to be low, but cannot be ignored, since ZIKV outbreaks affects an overwhelming number of individuals and GBS is a life-threatening debilitating condition, especially in pregnant women. ZIKV infection cases must be closely followed to assure prompt care to reduce the impact of GBS associated-sequelae on the quality of life of those affected.

Influence of IL-6, IL-8, and TGF-β 1 gene polymorphisms on the risk of human papillomavirus-infection in women from Pernambuco, Brazil

Human papillomavirus (HPV) infections are strongly associated with the development of cervical intraepithelial neoplasias and invasive cervical cancer. Polymorphisms in cytokine-encoding genes and behavioural cofactors could play an important role in protecting an individual against viral infections and cancer. Here, we investigated whether IL-6 -174 G>C, IL-8 +396 G>T, and TGF-β1 +869 G>C and +915 G>C polymorphisms were associated with susceptibility to HPV infection in women from north-east (Pernambuco) Brazil. We analysed 108 healthy uninfected women (HC) and 108 HPV-positive women with cervical lesions. Genetic polymorphisms were assessed using Sanger sequencing and polymerase chain reaction-restriction fragment length polymorphism. Comparison of the distribution of the genotypic and allelic frequencies of the IL-18 +396 T>G polymorphism between HPV infected woman an uninfected controls showed that the GG genotype and G allele were both more frequent in the HC group, and were associated with protection from HPV infection (p = 0.0015; OR = 0.29 CI95% = 0.13-0.61; p = 0.0005; OR = 0.45 CI95% 0.29-0.7, respectively). Individuals from the control group could have previously had HPV infection that was spontaneously eliminated; however, it was undetectable at the time of sample collection. Based on our findings, we hypothesize that the IL-8 +396 G>T polymorphism could interfere with susceptibility to HPV infection, by modulating the ability of immune system to fight the virus.

Dentifrice Containing Extract of Rosmarinus officinalis Linn: An Antimicrobial Evaluation

Abstract This study aimed to evaluate the antimicrobial activity of a dentifrice containing an alcoholic extract of rosemary on oral bacteria, compared to a commercially available herbal dentifrice. Standard strains of Streptococcus mutans (ATCC 25175), Streptococcus oralis (ATCC 9811) and Lactobacillus rhamnosus (ATCC 7469) were used, as well as different toothpastes based on rosemary (TR), on propolis (TH), triclosan (positive control) (TPC) and non-fluoridated dentifrice (negative control) (TNC). Bacteria were seeded in Petri dishes and paper discs soaked with dilutions of dentifrice placed on the plates. The inhibition halos were analyzed. It was observed that TR did not show statistical difference in relation to the TH to inhibit S. mutans and S. oralis, while TH was more active against L. rhamnosus. The toothpaste containing rosemary extract had the ability to inhibit the growth of S. mutans, S. oralis and L. rhamnosus, revealing an antimicrobial activity similar to commercially available toothpastes for inhibition of S. mutans and S. oralis.

Resumo O estudo teve como objetivo avaliar a atividade antimicrobiana de um dentifrício extrato alcoólico de alecrim sobre bactérias orais, comparando-o a um dentifrício herbal disponível no mercado. Cepas padrão de Streptococcus mutans (ATCC 25175), Streptococcus oralis (ATCC 9811) e Lactobacillus rhamnosus (ATCC 7469) foram utilizadas, bem como diferentes dentifrícios à base de alecrim (TR), própolis (TH), triclosan (controle positivo) (TPC) e sem flúor (controle negativo) (TNC). Placas de Petri foram inoculadas com as bactérias e discos de papel embebidos com diluições de cada dentifrício foram colocados nas placas. Em seguida, foram analisados os halos de inibição. Observou-se que o TR não mostrou diferença estatística em relação ao TH para inibição dos S. mutans e S. oralis, enquanto TH foi mais ativo contra L. rhamnosus. O dentifrício contendo extrato de alecrim foi capaz de inibir o crescimento de S. mutans, S. oralis e L. rhamnosus, revelando uma atividade antimicrobiana semelhante ao dentifrício disponível comercialmente na inibição de S. mutans e S. oralis.

DEFB1 gene polymorphisms and tuberculosis in a Northeastern Brazilian population

Abstract β-Defensin-1, an antimicrobial peptide encoded by the DEFB1 gene, is known to play an important role in lung mucosal immunity. In our association study we analyzed three DEFB1 functional polymorphisms -52G>A (rs1799946), -44C>G (rs1800972) and -20G>A (rs11362) in 92 tuberculosis patients and 286 healthy controls, both from Northeast Brazil: no association was found between the studied DEFB1 polymorphisms and the disease. However we cannot exclude that this lack of association could be due to the low number of subjects analyzed, as suggested by the low statistical power achieved for the three analyzed SNPs (values between 0.16 and 0.50).

CCR2 and CCR5 genes polymorphisms in women with cervical lesions from Pernambuco, Northeast Region of Brazil: a case-control study

Polymorphisms in chemokine receptors play an important role in the progression of cervical intraepithelial neoplasia (CIN) to cervical cancer (CC). Our study examined the association of CCR2-64I (rs1799864) andCCR5-Δ32 (rs333) polymorphisms with susceptibility to develop cervical lesion (CIN and CC) in a Brazilian population. The genotyping of 139 women with cervical lesions and 151 women without cervical lesions for the CCR2-64I and CCR5-Δ32 polymorphisms were performed using polymerase chain reaction-restriction fragment length polymorphism. The individuals carrying heterozygous or homozygous genotypes (GA+AA) for CCR2-64I polymorphisms seem to be at lower risk for cervical lesion [odds ratio (OR) = 0.37, p = 0.0008)]. The same was observed for the A allele (OR = 0.39, p = 0.0002), while no association was detected (p > 0.05) with CCR5-Δ32 polymorphism. Regarding the human papillomavirus (HPV) type, patients carrying the CCR2-64Ipolymorphism were protected against infection by HPV type 16 (OR = 0.35, p = 0.0184). In summary, our study showed a protective effect ofCCR2-64I rs1799864 polymorphism against the development of cervical lesions (CIN and CC) and in the susceptibility of HPV 16 infection.

Lactotransferrin gene functional polymorphisms do not influence susceptibility to human immunodeficiency virus-1 mother-to-child transmission in different ethnic groups

Lactotransferrin, also known as lactoferrin, is an iron binding glycoprotein that displays antiviral activity against many different infectious agents, including human immunodeficiency virus (HIV)-1. Lactotransferrin is present in the breast milk and in the female genitourinary mucosa and it has been hypothesised as a possible candidate to prevent mother-to-child HIV-1 transmission. To verify if two functional polymorphisms, Thr29Ala and Arg47Lys, in the lactotransferrin encoding gene (LTF) could affect HIV-1 infection and vertical transmission, a preliminary association study was performed in 238 HIV-1 positive and 99 HIV-1 negative children from Brazil, Italy, Africa and India. No statistically significant association for the Thr29Ala and Arg47Lys LTF polymorphisms and HIV-1 susceptibility in the studied populations was found. Additionally LTF polymorphisms frequencies were compared between the four different ethnic groups.

NLRP3 polymorphism is associated with protection against human T-lymphotropic virus 1 infection

Inter-individual heterogeneity in the response to human T-lymphotropic virus 1 (HTLV-1) infection has been partially attributed to host genetic background. The antiviral activity of the inflammasome cytoplasmic complex recognises viral molecular patterns and regulates immune responses via the activation of interleukin (IL)-1 family (IL-1, IL-18 and IL-33) members. The association between polymorphisms in the inflammasome receptors NLRP1 and NLRP3 and HTLV-1 infection was evaluated in a northeastern Brazilian population (84 HTLV-1 carriers and 155 healthy controls). NLRP3 rs10754558 G/G was associated with protection against HTLV-1 infection (p = 0.012; odds ratio = 0.37). rs10754558 affects NLRP3 mRNA stability; therefore, our results suggest that higher NLRP3 expression may augment first-line defences, leading to the effective protection against HTLV-1 infection.

DEFB1 polymorphisms are involved in susceptibility to human papillomavirus infection in Brazilian gynaecological patients

The human beta defensin 1 (hBD-1) antimicrobial peptide is a member of the innate immune system known to act in the first line of defence against microorganisms, including viruses such as human papillomavirus (HPV). In this study, five functional polymorphisms (namely g-52G>A, g-44C>G and g-20G>A in the 5’UTR and c.*5G>A and c.*87A>G in the 3’UTR) in the DEFB1 gene encoding for hBD-1 were analysed to investigate the possible involvement of these genetic variants in susceptibility to HPV infection and in the development of HPV-associated lesions in a population of Brazilian women. The DEFB1 g-52G>A and c.*5G>A single-nucleotide polymorphisms (SNPs) and the GCAAA haplotype showed associations with HPV-negative status; in particular, the c.*5G>A SNP was significantly associated after multiple test corrections. These findings suggest a possible role for the constitutively expressed beta defensin-1 peptide as a natural defence against HPV in the genital tract mucosa.

Evaluation of a nested-pcr for Mycobacterium tuberculosis detection in blood and urine samples

The polymerase chain reaction (PCR) and its variations, such as the nested-PCR, have been described as promising techniques for rapid diagnosis of tuberculosis (TB). With the aim of evaluating the usefulness of a nested-PCR method on samples of blood and urine of patients suspected of tuberculosis we analyzed 192 clinical samples, using as a molecular target the insertion element IS6110 specific of M. tuberculosis genome. Nested-PCR method showed higher sensitivity in patients with extrapulmonary tuberculosis (47.8 percent and 52 percent in blood and urine) when compared to patients with the pulmonary form of the disease (sensitivity of 29 percent and 26.9 percent in blood and urine), regardless of the type of biological sample used. The nested-PCR is a rapid technique that, even if not showing a good sensitivity, should be considered as a helpful tool especially in the extrapulmonary cases or in cases where confirmatory diagnosis is quite difficult to be achieved by routine methods. The performance of PCR-based techniques should be considered and tested in future works on other types of biological specimens besides sputum, like blood and urine, readily obtainable in most cases. The improving of M. tuberculosis nested-PCR detection in TB affected patients will give the possibility of an earlier detection of bacilli thus interrupting the transmission chain of the disease.

Fequency distribution of HLA DQ2 and DQ8 in celiac patients and first-degree relatives in Recife, northeastern Brazil

AIMS: The aim of this study was to evaluate the frequencies of the HLA genotypes DQ2 and DQ8 and the alleles A1*05, A1*0201, B1*0201 and B1*0302 in individuals with celiac disease in Recife, northeastern Brazil. METHODS: HLA DQ2 and DQ8 genotyping was performed for 73 individuals with celiac disease and 126 first-degree relatives with negative transglutaminase serology. The alleles DQA1*05, DQA1*0201, DQB1*02 and DQB1*0302 were identified by sequencing using specific primers and the EU-DQ kit from the Eurospital Laboratory, Trieste, Italy and double-checked by the All Set SPP kit (Dynal). RESULTS: Among the 73 cases, 50 (68.5 percent) had the genotype DQ2, 13 (17.8 percent) had DQ8, 5 (6.8 percent) had DQ2 and DQ8, and 5 did not have any of these genotypes. Among the 5 negative individuals, four had the B1*02 allele and one did not have any of the alleles studied. B1*02 was the most frequent allele in both groups (94 percent in the patients and 89 percent in the control relatives). CONCLUSIONS: In this study, celiac disease was associated with the genotypes DQ2 and DQ8. DQ2 predominated, but the distribution of the frequencies was different from what has been found in European populations and was closer to what has been found in the Americas. The high frequencies of the HLA genotypes DQ2 and DQ8 that were found in first-degree relatives would make it difficult to use these HLA genotypes for routine diagnosis of celiac disease in this group.

Mannose binding lectin genes (MBL2) polymorpshisms and the periodontal disease in diabetic patients / Polimorfimos da lectina de ligação da manose (MBL2) e doença periodontal em pacientes diabéticos

PURPOSE: To assess the association between the polymorphism in exon-1 of the MBL2 gene and the periodontal disease in type 2 diabetic patients. METHODS: The sample comprised of 100 patients, who were submitted to a clinical periodontal examination that evaluated in six sites per tooth the probing depth (PD), bleeding on probing (BOP), clinical attachment loss (CAL), plaque index (PI) and the number of teeth present. Periodontal disease was defined as at least four sites with loss of attachment of >5 mm, with one or more of those sites having a pocket of > 4 mm. The collection of scaling cells from the oral mucosa was carried out and the detection of MBL2 polymorphism was made by real time PCR and melting temperature curve analysis. RESULTS: In a type 2 diabetic population, no significant statistical differences in MBL2 polymorphisms genotype or allele frequencies were observed among subjects with periodontal disease. CONCLUSION: This study indicates that the polymorphisms in exon-1 of the MBL2 gene are not related to periodontal disease in a type 2 diabetic population.

OBJETIVO: Avaliar a associação entre o polimorfismo no exon-1 do gene MBL2 e a doença periodontal em pacientes diabéticos tipo 2. MÉTODO: A amostra foi composta por 100 pacientes que foram submetidos a um exame clínico periodontal que avaliou seis sítios por dente a profundidade de sondagem (PS), sangramento à sondagem (SS), perda de inserção clínica (PIC), índice de placa (IP) e o número de dentes presente. A doença periodontal foi definida como pelo menos quatro sítios com perda de inserção de >5mm, com um ou mais destes sítios tendo uma bolsa de >4mm. Foram coletadas células de descamação da mucosa oral e a detecção do polimorfismo foi feita através da PCR em tempo real e análise da temperatura de melting. RESULTADOS: Em uma população de diabéticos tipo 2, não houve diferenças estatisticamente significantes nos genótipos do polimorfismo da MBL2 ou freqüência alélica observadas entre os indivíduos com doença periodontal. CONCLUSÃO: Este estudo indicou que o polimorfimos no exon-1 do gene da MBL2 não foi relacionado à doença periodontal em uma população de diabéticos tipo 2.

Infecção cervical por papilomavírus humano: genotipagem viral e fatores de risco para lesão intraepitelial de alto grau e câncer de colo do útero / Human papillomavirus cervical infection: viral genotyping and risk factors for high-grade squamous intraepithelial lesion and cervix cancer

OBJETIVO: analisar, em mulheres com HPV em colo do útero, as características da infecção viral e os fatores de risco para lesão intraepitelial de alto grau e carcinoma cervical. MÉTODOS: realizou-se um estudo caso-controle com mulheres com HPV em colo do útero atendidas em serviço de Ginecologia de referência vinculado ao SUS, em Recife, Nordeste do Brasil. No grupo de casos (72 mulheres com lesão intraepitelial de alto grau ou carcinoma cervical) e de controles (176 mulheres com colpocitologia normal ou com alterações benignas), foram pesquisados seis genótipos virais (HPV 16, 18, 31, 33, 6 e 11) em material da ecto- e endocérvice com primers MY09/MY11. As variáveis independentes foram hierarquizadas em três níveis de determinação: distal (sociodemográficas), intermediário (comportamentais) e proximal (realização anterior de colpocitologia). A homogeneidade das proporções foi testada (χ2). Obtiveram-se ORs não ajustadas e, na modelagem final, realizou-se regressão logística hierarquizada com o ajuste do efeito de cada variável sobre o desfecho pelas variáveis do mesmo nível e de níveis anteriores de causalidade. RESULTADOS: em 76,6 por cento das 248 mulheres participantes do estudo, o genótipo viral da infecção cervical foi identificado. Predominaram genótipos de alto risco oncogênico (83,4 por cento nos casos e 67,1 por cento nos controles), principalmente HPV 16 e 31. Foram identificados como fatores de risco (a) distais: residir em zona rural (OR=2,7; IC95 por cento: 1,1-6,2), menos de três anos de estudo (OR=3,9; IC95 por cento: 2,0-7,5) e renda familiar inferior a dois salários mínimos (OR=3,3; IC95 por cento: 1,0-10,5); (b) intermediário: número de gestações igual ou superior a quatro (OR=2,0; IC95 por cento: 1,0-3,7); (c) proximal: ausência de colpocitologia anterior (OR=9,7; IC95 por cento: 2,4-38,2). CONCLUSÕES: em mulheres usuárias do SUS do Nordeste do Brasil predominam os genótipos virais 16 e 31 em infecções cervicais ...

PURPOSE: to analyze the characteristics of viral infection and the risk factors for high-grade squamous intraepithelial lesion and cervical carcinoma in women with cervical HPV infection. METHODS: a case-control study was conducted on women with cervical HPV at a Gynecology reference service enrolled at the Public Health System, located in Recife, Northeastern Brazil. The groups of cases (72 women with high-grade squamous intraepithelial lesion or cervical cancer) and controls (176 women with normal Pap smear or benign alterations) were investigated for six viral genotypes (HPV 16, 18, 31, 33, 6, 11) in ecto- and endocervical material using MY09/MY11 primers. The independent variables were ranked in three levels of determination: distal (sociodemographic), intermediate (behavioral) and proximal (previous Pap smear). The homogeneity of proportions was tested (χ2), unadjusted Odds Ratios (OR) were obtained and hierarchical logistic regression was applied to the final model, with adjustment of the effect of each variable to the outcome based on the variables in the same and previous levels of causality. RESULTS: the viral genotype of cervical infection was identified in 76.6 percent of the 248 women participating in the study. High-risk HPV genotypes (83.4 percent of cases and 67.1 percent of controls) were predominant, especially HPV 16 and 31. The distal risk factors identified were: living in a rural area (OR=2.71, 95 percentCI: 1.18-6.23), less than three years of study (OR=3.97, 95 percentCI: 2.09-7.54) and family income below two minimum wages (OR=3.30, 95 percentCI: 1.04-10.51); intermediate: four or more pregnancies (OR=2.00, 95 percentCI: 1.06-3.76); and proximal: absence of a previous Pap smear (OR=9.74, 95 percentCI: 2.48-38.28). CONCLUSIONS: genotypes 16 and 31 of cervical HPV infection are predominant among women assisted by the Public Health System in Northeastern Brazil. Socioeconomic and reproductive factors, as well ...

Genotipo MLB2 materno influencia a transmissao vertical em crianças brasileiras / MLB2 mothers' genotype influences HIV-1 vertical transmission in Brazilian children

O presente estudo analisa os polimorfismos geneticos no primeiro exon MBL2, em um coorte de 21 pares de maes e filhos infectados por HIV-1 e um coorte de 11 pares constituidos por maes infectadas por HIV-1 e filhos nao infectados, na cidade de Recife(PE), localizada no nordeste do Brasil, com objetivo de avaliar se o genotipo MBL2, de maes infectadas por HIV-1 poderia estar relacionado com transmissibilidade do virus para seus conceptos. Todas criancas nasceram de maes infectadas por HIV-1 que nao haviam recebido nenhum tratamento antiretroviral durante a gravidez e não foram submetidas a parto cesareano para prevenir transmissão. Maes que transmitiram HIV-1 a seus conceptos (MT) tinham frequencia mais alta (14 porcento) de genotipo 00 no MBL2(tipico de maus produtores de MBL) se comparado com frequencia de 0 porcento observada entre maes infectadas que transmitiram o virus para seus filhos (MNT). Esta diferença foi estatisticamente significante. A presença do genotipo 0 e 00 no alelo MBL2 em MT se associou com transmissao viral. O genotipo AA de MBL (associado com produçao normal de MBL) teve frequencia de 82 porcento em MNT, significantemente mais alta que a frequencia de 52 porcento de MT. A presença do alelo A em 91 porcento das MNT conferiu menor risco de transmissao vertical no coorte estudado. Nossos resultados sugerem que a transmissao vertical de HIV-1 depende somente do genotipo MBL2 da crianca e da mae, nas quais os niveis da proteina MBL poderiam desempenhar um importante papel na transmissao do virus