Hepatitis E virus: Western Cape, South Africa

Abstract

Aim: To conduct a prospective assessment of anti-hepatitis E virus (HEV) IgG seroprevalence in the Western Cape Province of South Africa in conjunction with evaluating risk factors for exposure.

Methods: Consenting participants attending clinics and wards of Groote Schuur, Red Cross Children's Hospital and their affiliated teaching hospitals in Cape Town, South Africa, were sampled. Healthy adults attending blood donor clinics were also recruited. Patients with known liver disease were excluded and all major ethnic/race groups were included to broadly represent local demographics. Relevant demographic data was captured at the time of sampling using an interviewer-administered confidential questionnaire. Human immunodeficiency virus (HIV) status was self-disclosed. HEV IgG testing was performed using the Wantai^® assay.

Results: HEV is endemic in the region with a seroprevalence of 27.9% (n = 324/1161) 95%CI: 25.3%-30.5% (21.9% when age-adjusted) with no significant differences between ethnic groups or HIV status. Seroprevalence in children is low but rapidly increases in early adulthood. With univariate analysis, age ≥ 30 years old, pork and bacon/ham consumption suggested risk. In the multivariate analysis, the highest risk factor for HEV IgG seropositivity (OR = 7.679, 95%CI: 5.38-10.96, P < 0.001) was being 30 years or older followed by pork consumption (OR = 2.052, 95%CI: 1.39-3.03, P < 0.001). A recent clinical case demonstrates that HEV genotype 3 may be currently circulating in the Western Cape.

Conclusion: Hepatitis E seroprevalence was considerably higher than previously thought suggesting that hepatitis E warrants consideration in any patient presenting with an unexplained hepatitis in the Western Cape, irrespective of travel history, age or ethnicity.

Keywords: Genotype; Hepatitis E; Pork consumption; Seroprevalence; South Africa.

Figure 1

Overall seroprevalence curve and individual seroprevalence curves in 3 racial groups in Western Cape, South Africa. Anti-HEV IgG seroprevalence by age in Western Cape, South Africa.

Figure 2

A maximum likelihood tree constructed in MEGA6 from an alignment of a 301nt fragment of ORF2. Bootstrap support above 60% is shown. Our patient’s viral sequence, GenBank accession KT833800, is highlighted in red. The tree is rooted on the HEV reference sequence (genotype 1). Sequences for comparison have names starting with genotype, followed by Genbank accession number, followed by country ISO 3166-1 abbreviation (CA: Canada; ES: Spain; GB: United Kingdom; JP: Japan; NL: The Netherlands; TW: Taiwan; US: United States of America; ZA: South Africa), and ending in source (D: Deer; H: Human; P: Pig). The patient’s viral sequence clusters within genotype 3 (with subgenotype 3e), in keeping with other viruses recently described in South Africa[11,12,24].