Hepatitis E virus infection in Thai blood donors.

BACKGROUND: Hepatitis E virus (HEV) infection in several industrialized and developing countries is associated with the consumption of pork and other meat products, an exposure risk among the majority of blood donors. We aimed to evaluate the prevalence of HEV in plasma from healthy blood donors in Thailand. STUDY DESIGN AND METHODS: We screened blood samples collected between October and December 2015, from 30,115 individual blood donors in 5020 pools of six, for HEV RNA using in-house real-time reverse-transcription polymerase chain reaction (RT-PCR). Thrice-reactive samples were subjected to a commercial real-time RT-PCR (cobas HEV test) and evaluated for anti-HEV immunoglobulin M and immunoglobulin G antibodies. Genotyping using nested RT-PCR, nucleotide sequencing, and phylogenetic analysis was performed. RESULTS: Twenty-six donors were positive for HEV RNA by the in-house assay, nine of whom were also positive by cobas test. None of the latter were reactive for anti-HEV immunoglobulin M or immunoglobulin G antibodies. Six samples were successfully genotyped and found to be HEV genotype 3. Thus, the frequency of HEV infection among healthy Thai blood donors is 1 in 1158. CONCLUSION: The presence of HEV RNA in the Thai blood supply was comparable to the rates reported in western European countries, but higher than in North America and Australia.

Response of Severe EV71-Infected Patients to Hyperimmune Plasma Treatment: A Pilot Study.

Hand, foot, and mouth disease (HFMD) is highly prevalent in East and Southeast Asia. It particularly affects children under five years of age. The most common causative agents are coxsackieviruses A6 and A16, and enterovirus A71 (EV71). The clinical presentation is usually mild and self-limited, but, in some cases, severe and fatal complications develop. To date, no specific therapy or worldwide vaccine is available. In general, viral infection invokes both antibody and cell-mediated immune responses. Passive immunity transfer can ameliorate the severe symptoms of diseases such as COVID-19, influenza, MERS, and SARS. Hyperimmune plasma (HIP) from healthy donors with high anti-EV71 neutralizing titer were used to transfuse confirmed EV71-infected children with neurological involvement (n = 6). It resulted in recovery within three days, with no neurological sequelae apparent upon examination 14 days later. Following HIP treatment, plasma chemokines were decreased, whereas anti-inflammatory and pro-inflammatory cytokines gradually increased. Interestingly, IL-6 and G-CSF levels in cerebrospinal fluid declined sharply within three days. These findings indicate that HIP has therapeutic potential for HFMD with neurological complications. However, given the small number of patients who have been treated, a larger cohort study should be undertaken. Successful outcomes would stimulate the development of anti-EV71 monoclonal antibody therapy.

A Nationwide Survey of the Seroprevalence of Hepatitis E Virus Infections Among Blood Donors in Thailand.

Hepatitis E virus (HEV) is a common cause of acute hepatitis infections. Our previous 3-year study at two large Thai hospitals established an occurrence of 4-5% of HEV infections from swine HEV genotype 3 in suspected acute hepatitis patients, with the high incidence in older adults. This study was a serosurvey to determine the prevalence of HEV infections among Thai adults. We obtained sera from 630 healthy blood donors with a median age of 38 (18-64) years who attended Thai Red Cross transfusion units throughout Thailand. The donors were domiciled in 16 provinces in the northern (n = 159), central (n = 193), northeastern (n = 158), and southern (n = 120) regions. The seroprevalence of IgG antibody to HEV (anti-HEV) was determined by the EUROIMMUN test kit, using indirect enzyme-linked immunosorbent assay (ELISA) based on recombinant antigens derived from ORF2 of HEV genotypes 1 and 3. Demographic data, including information related to HEV infection risk (the number of pigs and the proportion of Muslims in each province), were also obtained. The overall anti-HEV prevalence among Thai adults was 29.7%. The frequencies of anti-HEV found in the northern (28.9%, 95% confidence interval [CI] = 22.4-36.4), northeastern (34.8%, 95% CI = 27.8-42.5), and central (35.8%, 95% CI = 29.3-42.7) regions were similar, whereas the frequency in the southern (14.2%, 95% CI = 9.0-21.5) region, known to have a large Muslim population, was low. An increasing frequency of the specific antibody was observed among the elderly. A low HEV infection rate was associated with an Islamic population where there are low number of pigs and low swine consumption. Furthermore, the higher anti-HEV incidences in the northeastern provinces might relate to the local cultural practice of consuming undercooked pork. Besides the need for an HEV vaccination in the future, there is a requirement for rapid early diagnosis; the undertaking of prevention-management campaigns might also reduce the number of infected patients.