A 1-year study of the epidemiology of hepatitis A virus in Tunisia

Abstract

This 1-year (September 2000 to August 2001) prospective study investigated the presence of hepatitis A virus (HAV) in the population of Monastir, Tunisia (86 serum samples), in the influents and effluents of two wastewater treatment plants, and in shellfish harvested in the coastal areas of Monastir, Bizerte and Sfax (January 2001 to May 2001). The virus was detected by RT-PCR using primers targeted at the VP3-VP1 region. An epidemic of HAV infection was observed during the winter months, with a peak in January. The presence of the virus was relatively constant in the influents and effluents of the wastewater treatment plants, and the virus was found in shellfish from the Monastir area during the months of January and February. The genotype IA strain was recovered most frequently from human serum and wastewater samples. The observation that the peak of the epidemic was during the winter months suggests that transmission of HAV is related to climatic factors and, presumably, to shellfish consumption.

Detection and Molecular Characterization of Hepatitis A Virus from Tunisian Wastewater Treatment Plants with Different Secondary Treatments

“…Despite of the improvement of hygiene conditions in many urban areas, the incidence of hepatitis has been not reduced in those areas. This result is in accordance with environmental studies conducted in the country, including analysis of wastewater samples, where HAV rates ranged between 46% and 68.3% (4,31,40). Seroprevalence data in Tunisia and in some regions of the Middle East and North Africa showed high HAV endemicity also, with levels ranging between 83% and 96.4% (12,31,36,37).…”

“…Results of the phylogenetic analysis of HAV sequences obtained from wastewater samples were in accordance with several epidemiological studies showing the predominance of subgenotype IA in Tunisia over several years (4,31,42). Interestingly, some strains belonging to this subgenotype were closely related to European strains, confirming the circulation of this subgenotype variant in the Mediterranean region (49).…”

“…HAV is still endemic in Tunisia, with a high/intermediate ranking (4,12,31,36,37), and in the Mediterranean region (8,38,39). Despite the potential public health hazard linked to the use of contaminated treated sewage, few studies have been carried out on the prevalence of HAV in wastewater and its seasonal and geographical distribution in Tunisia.…”

“…The obtained sequences, including 14 reference sequences retrieved from GenBank, were corrected using the DNASTAR Lasergene SeqMan program (DNASTAR, USA) and then aligned using MEGA6 and the Clustal W algorithm (30). In addition, three subgenotype IA sequences, two corresponding to clinical strains TunS-01-01and TunS-05-01, identified in serum samples collected in 2001 from Jammel and Monastir hospitals, and the third corresponding to environmental strain TunEU-05-01, collected from raw wastewater in the Monastir region (2001) (31), were also included in the analysis. Inter-and intragenotype nucleotide identity percentages were calculated using the DNASTAR Lasergene MegAlign program.…”

Seroprevalence and Molecular Characterisation of Human Hepatitis A virus in Serum Samples of Tunisian Patients with Clinical Symptoms of Viral Hepatitis

“…Although HAV incidence in Tunisia was studied [14], the surveillance of this infection need to be continued and the acquired data about this infection need to be updated and evaluated. Unfortunately, the surveillance of this infection was not done in a continued manner lack of facilities and sometimes practical reasons.…”