Detection of hepatitis A virus in shellfish (Mytilus galloprovincialis) with RT-PCR

New approaches in microbial pathogen detection

Viruses are common causes of foodborne outbreaks. Viral diseases have low fatality rates but transmission to humans via food is important due to the high probability of consuming fecally contaminated food or water because of poor food handling. Because of the low infectious doses of some foodborne viruses, there is a need for standardization and the development of new sensitive methods for detecting viruses. The focus is on molecular and non-molecular approaches, and emerging methods for the detection of foodborne viruses. The detection of noroviruses, hepatitis A and E viruses, rotaviruses and adenoviruses will be discussed. The chapter will conclude with insights into future research directions.

Hepatitis A virus detection in food: current and future prospects

Hepatitis A virus (HAV) is responsible for around half of the total number of hepatitis infections diagnosed worldwide. HAV infection is mainly propagated via the faecal-oral route and as a consequence of globalisation, transnational outbreaks of foodborne infections are reported with increasing frequency. Molecular procedures are now available and should be employed for the direct surveillance of HAV in food and environmental samples.

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

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.

Diagnosis of hepatitis a virus infection: a molecular approach

Current serologic tests provide the foundation for diagnosis of hepatitis A and hepatitis A virus (HAV) infection. Recent advances in methods to identify and characterize nucleic acid markers of viral infections have provided the foundation for the field of molecular epidemiology and increased our knowledge of the molecular biology and epidemiology of HAV. Although HAV is primarily shed in feces, there is a strong viremic phase during infection which has allowed easy access to virus isolates and the use of molecular markers to determine their genetic relatedness. Molecular epidemiologic studies have provided new information on the types and extent of HAV infection and transmission in the United States. In addition, these new diagnostic methods have provided tools for the rapid detection of food-borne HAV transmission and identification of the potential source of the food contamination.