Foodborne infections are described as the illness caused by consumption of contaminated food. It is described as a growing public health burden worldwide. Among all infections viral meat borne illnesses have come up as the significant cause of Foodborne infection.
- Mechanism of viral infection
Mechanism of viral infection to the host cell is not random, they have specific predilection site found in group of cells or hosts. Once viruses enter the host, they take complete hold of host synthetic machinery and redirect it to synthesize viral proteins and genomic material by using host’s cellular enzymes.
How viral meat contamination occurs?
Viral meat contamination occurs by two ways; Clinical contamination and Environmental contamination.
- Clinical contamination
Clinical contamination involves the entry and replication of virus in the host products of which are then served to the consumers without virus being inactivated.
- Environmental contamination
Environmental contamination refers to the direct contamination of food during handling and processing by infected workers i.e. via sneezing, coughing, and fecal material.
Inside food material viral replication is stopped as they require some living medium for this, so viruses don’t affect the colour, smell and taste of food. Viruses that are most commonly associated with meat borne infections are Norovirus, Hepatovirus A, Orthohepevirus A (Hepatitis E virus).
- Norovirus (NoV)
Norovirus (NoV) is non-enveloped, ssRNA that is 27-30 nm and Icosahedral in symmetry. After ingestion it is replicated in small intestine causing mucosal lesions.
It is reported by Centers of Disease Control and Prevention that 50% of Foodborne outbreaks occur by NoV. NoV infection is characterized by nausea, vomiting, diarrhoea, myalgias, abdominal pain and enterocolitis in infants.
- Hepatitis A 2 virus (HAV)
Hepatitis A 2 virus (HAV) belongs Picornaviridae family having 27-32nm protein capsid and RNA genome. Contamination of meat from HAV is by sewage water and is transmitted by faecal-oral route.
Minimum infectious dose of HAV is 10 to 100 infectious particles with an incubation period of 10-50 days. The virus replicates in liver cells characterized by fever, malaise, nausea, joint pain, dark coloured urine, pale stools, anorexia, abdominal discomfort and jaundice.
- Hepatitis E (HEV)
Hepatitue E virus (HEV) has significant importance as an emerging infection. It is a non-enveloped, positive-sensed RNA, with 27-34nm diameter and an icosahedral in symmetry.
HEV replicates in liver and gall-bladder, also seen in small intestine, lymph nodes, and salivary glands. Incubation period of HEV is 3-8 weeks. Infection goes usually asymptomatic in children.
In adults it has symptoms like jaundice, malaise, anorexia, enlarged tender liver, abdominal pain, arthralgia, hepatomegaly, fever and vomiting. Increased mortality and morbidity is associated with highly immuno compromised patients.
- Diagnosis
Detection of viruses in food by culturing method is very difficult, but it can be directly detected in food extracts using RT-PCR. Gastroenteric viruses are diagnosed by examining stool samples with electron microscopy, agglutination and ELISA can also be done in order to diagnose viruses in meat and meat products.
- Control
For controlling and preventing viral diseases with food borne transmission diagnostic methods and surveillance systems must be improved. Contaminated meat should be discarded immediately to prevent the human exposure to these infections.
- Conclusion
The fact that meat sector is contributing 1.4% in overall GDP emphasizes the consideration of meat borne viral infections as a serious concern. Unlike bacterial infections, current food safety guidelines have not been validated for Foodborne viruses.
Therefore, there is a lack in understanding the efficacy of control on viruses and currently no reliable indicator organisms of viruses are present.
As viral contamination of food can occur anywhere in the process “from farm to fork” so good agricultural and manufacturing practices are needed.
Authors: Shunazia Saquib *1, M. Tariq Javed1, Aisha Khatoon 1, Ashiq Ali1, Sania Saeed1, Farwa Rabab 1.
1 Department of Pathology, Faculty of Veterinary Science, University of Agriculture Faisalabad, Pakistan.
* Corresponding Author Email: shunazia_saquib@yahoo.com