Food-Borne Viral Infections: Diagnosis & Control Measures

Foodborne viral infections are caused by viruses that can contaminate foods during all stages of the food supply chain. The most common types of foodborne viral infections are noroviruses and hepatitis A virus (HAV). Rotavirus is also associated with foodborne illness.

Foodborne viruses originate from the human intestine and are excreted in high numbers in the faeces or through emesis. The low infectious dose and robust survival in food and various environments facilitates the spread of viral infections.

General Disease Control Methods​

i) Increasing the host resistance​

You can achieve this in two ways:

1. Proper and improved nutrition
2. Vaccination

ii) Taming the environment​

Here, you eliminate or reduce the hazards / predisposing factors to the disease. You can achieve this through environmental sanitation, e.g.

1. Water should be safe and adequate
2. The housing should be sound to eliminate physical and biological hazards
3. Food hygiene should be high throughout all the stages of production. Check and control the type of soil, the food storage premises, and even the chemicals used in production. Inspect and reduce all sources of contamination (including the health of human handlers). Refrigerate stored foods at the right temperature.
4. Conduct mass education on food hygiene
5. Disinfect areas where the sick animals stay to avoid contamination and cross-contamination to a healthy host. You can use chemical disinfectants or irradiation for this purpose.
6. Practice proper waste and sewage disposal. Properly manage and dispose industrial wastes as well
7. Control the quality of the air you breathe through sanitation or filtering
8. Minimize contact with animals to reduce chances of spread of zoonotic diseases

Some of the most common food-borne viral infections include:

 

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Infectious Hepatitis​

Hepatitis is a common / prevalent infection that is easy to diagnose. It is caused by virus types A and B.

Aetiology​

• When the disease occurs, the virus is shed through the blood, stool, and urine of the infected person.
• The disease is more severe in children. Adults experience a protracted period of the disease.

Transmission​

• Majorly transmitted through oral consumption of contaminated water by stool or urine of an infected person.
• You can also get it through contact with the blood of an infected person.
• Hepatitis type B can be transmitted through sexual contact.

Symptoms​

Incubation period is between two and six weeks.

It takes quite long to get a slight manifestation. Some of the noticeable symptoms include:

• Slight increase in body fever
• General malaise
• Faintness and weakness
• Anorexia
• Nausea
• Abdominal discomfort
• Liver failure symptoms (jaundice)
• Ascites (accumulation of fluid in the abdomen)
• Changes in urine colour due to presence of bile

Diagnosis​

Once the incubation period is complete, the onset of the symptoms is characteristic.

Test the liver functions and identify the virus in the blood or urine through cultural isolation.

Control measures​

• Vaccination is the most effective way.
• Maintain high hygiene standards for food, water, and self.
• Proper sewage treatment and disposal channels.

 

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Poliomyelitis​

This disease can occur in apparent forms (i.e. cases where the disease is present but the patients do not show any symptom). It is caused by polio virus 1, 2, and 3.

Aetiology​

The virus is shed through the stool and pharyngeal excretions. People catch the virus through consumption of contaminated water, milk, and other fluid foods.

Symptoms​

Incubation takes between seven and 10 days.

• It starts with fever followed by headache
• General malaise
• Constipation
• Stiffness of the neck
• Paralysis of limbs
• Meningitis may also occur

Diagnosis​

• The symptoms are helpful in making a tentative diagnosis.
• Isolate the virus from the stool and other secretions of the body.
• Serological tests are also helpful in diagnosing this disease.

Control measures​

• Vaccination is very effective; done only once and remains effective for life.
• Maintaining high standards of personal hygiene is crucial. Food and must be kept clean and uncontaminated.