Detection and quantification of hepatitis E virus in the absence of IgG and IgM anti-HEV in HIV-positive patients

AIMS

To improve RT-qPCR with an internal control and a synthetic standard curve to detect HEV in HIV co-infected patients.

METHODS AND RESULTS

A single-stranded RNA (ssRNA) and a double-stranded DNA (dsDNA) synthetic curve were designed, compared to the international reference panel for HEV genotypes, and tested to quantify and detect a reference panel for HEV genotypes. The detection limit of the RNA synthetic curve (50 copies per ml) was better than the DNA synthetic curve (100 copies per ml) and the WHO standard curve (250 copies per ml). Then, 280 serum samples from HIV-positive patients were tested for HEV RNA, which was detected in 3·6% of serum samples. The viral load ranged from 2 × 10² copies per ml to 4·78 × 10⁸ copies per ml. HEV IgM/IgG antibodies were not detected in the RNA-positive patients. Sequencing analysis of HEV showed that the virus belongs to genotype 3 (HEV GT3).

CONCLUSIONS

Real-time PCR was a useful tool to estimate co-infection with HEV/HIV, even in patients with low viral loads and undetectable anti-HEV IgG and IgM antibodies.

SIGNIFICANCE AND IMPACT OF THE STUDY

Hepatitis E virus genotype 3 (HEV GT3) has been associated with silent chronic hepatitis and cirrhosis in HIV-positive subjects worldwide, but there is a lack of data on this co-infection in Brazil.

Phylogenetic analyses of the hemagglutinin gene of wild-type strains of canine distemper virus in southern Brazil

This study examined the phylogenetic relationship of strains of canine distemper virus (CDV) collected from Paraná State, Brazil, based on the hemagglutinin gene. Urine samples were collected from 4 dogs from northern Paraná State that demonstrated clinical manifestations of canine distemper. The participation of CDV was initially confirmed by RT-PCR targeting the nucleocapsid protein, after which the complete hemagglutinin gene was sequenced from each sample. Sequences were deposited in and compared with those already in GenBank. Phylogenetic analyses, using amino acid and nucleotide sequences based on the hemagglutinin gene, demonstrated that these strains of CDV are closely related to those from the Europe 1 lineage of CDV, with marked differences from other recognized geographical clusters of CDV isolates and from the vaccine strains. The strains of CDV from this region of southern Brazil appear to be related to those from Europe 1.

Molecular detection and characterization of hepatitis E virus in naturally infected pigs from Brazilian herds

The aim of this study was to investigate the presence of swine hepatitis E virus (HEV) from pigs of different production categories and from different pig farms in South Brazil. A total of 170 porcine faecal samples from breeder sows, boars, suckling piglets, weaned and growing pigs were collected from 14 pig farms. The faecal samples were screened by nested RT-PCR using primers targeting the ORF2 region of HEV genome. The samples that were positive from this screening were used in a nested RT-PCR targeting the ORF1 region. The screening detected HEV RNA in 62.5% of the pig farms and in 15.3% of the faecal samples. In 15 faecal samples, it was possible to amplify the HEV RNA with both the ORF1 and ORF2 regions. The phylogenetic analyses obtained for both ORFs confirmed that all of the Brazilian swine HEV isolates clustered with genotype 3b, the same genotype described previously in humans in Brazil.