Tracking the turnover of SARS-CoV-2 VOCs Gamma to Delta in a Brazilian state (Minas Gerais) with a high-vaccination status.

The emergence and global dissemination of Severe Acute Respiratory Syndrome virus 2 (SARS-CoV-2) variants of concern (VOCs) have been described as the main factor driving the Coronavirus Disease 2019 pandemic. In Brazil, the Gamma variant dominated the epidemiological scenario during the first period of 2021. Many Brazilian regions detected the Delta variant after its first description and documented its spread. To monitor the introduction and spread of VOC Delta, we performed Polymerase Chain Reaction (PCR) genotyping and genome sequencing in ten regional sentinel units from June to October 2021 in the State of Minas Gerais (MG). We documented the introduction and spread of Delta, comprising 70 per cent of the cases 8 weeks later. Comparing the viral loads of the Gamma and Delta dominance periods, we provide additional evidence that the latter is more transmissible. The spread and dominance of Delta did not culminate in the increase in cases and deaths, suggesting that the vaccination may have restrained the epidemic growth. Analysis of 224 novel Delta genomes revealed that Rio de Janeiro state was the primary source for disseminating this variant in the state of MG. We present the establishment of Delta, providing evidence of its enhanced transmissibility and showing that this variant shift did not aggravate the epidemiological scenario in a high immunity setting.

Epidemiology and evolution of Zika virus in Minas Gerais, Southeast Brazil.

Autochthonous Zika virus (ZIKV) transmission in Brazil was first identified in April 2015 in Brazil, with the first ZIKV-associated microcephaly cases detected in October 2015. Despite efforts on understanding ZIKV transmission in Brazil, little is known about the virus epidemiology and genetic diversity in Minas Gerais (MG), the second most populous state in the country. We report molecular and genomic findings from the main public health laboratory in MG. Until January 2020, 26,817 ZIKV suspected infections and 86 congenital syndrome cases were reported in MG state. We tested 8552 ZIKV and microcephaly suspected cases. Ten genomes were generated on-site directly from clinical samples. A total of 1723 confirmed cases were detected in Minas Gerais, with two main epidemic waves; the first and larger epidemic wave peaked in March 2016, with the second smaller wave that peaked in March 2017. Dated molecular clock analysis revealed that multiple introductions occurred in Minas Gerais between 2014 and 2015, suggesting that the virus was circulating unnoticed for at least 16 months before the first confirmed laboratory case that we retrospectively identified in December 2015. Our findings highlight the importance of continued genomic surveillance strategies combined with traditional epidemiology to assist public health laboratories in monitoring and understanding the diversity of circulating arboviruses, which might help attenuate the public health impact of infectious diseases.

Biochemical and Molecular Chitotriosidase Profiles in Patients with Gaucher Disease Type 1 in Minas Gerais, Brazil: New Mutation in CHIT1 Gene.

Chitotriosidase (ChT) is a human chitinase secreted by activated macrophages and its activity is used in therapeutic monitoring of Gaucher disease (GD), the most common lysosomal storage disease. About 6% of the population is homozygous for a duplication of 24 bp in exon 11 of the CHIT1 gene (dup24), which is the main polymorphism that results in the absence of ChT. As ChT enzyme activity can be used as a biomarker in GD, it is important to know the CHIT1 genotype of each patient. In this study, ChT activity and CHIT1 genotype were evaluated in 33 GD type 1 patients under treatment in the state of Minas Gerais, Brazil, and compared to healthy controls. As expected, the enzyme activity was found to be higher in GD type 1 patients than in healthy subjects. Four patients had no ChT activity. Their genotype revealed three patients (9%) homozygous for dup24 allele and one patient with two polymorphisms in exon 11: G354R and a 4 bp deletion at the exon-intron 11 boundary (g.16993_16996delGAGT), the later described for the first time in literature. Two other patients with lower ChT activity presented a polymorphism in exon 4 (c.304G>A, p.G102S), without dup24 allele. In conclusion, this study demonstrated that ChT activity can be used for therapeutic monitoring in 82% of GD patients of the state of Minas Gerais, Brazil.