Disease Associated With Viruses


Viral disease:

A Virus is a genetic entity that comprises of either DNA or RNA, surrounded by a protein coat and require a host to survive. Viral disease is a condition, when a pathogenic virus attacks host, weakens its immune system and replicate inside host cells to further spread the infection.

Origin of virus:

Human infectious viruses have emerged from non-human reservoirs like – poultry, farm mammals, wild animals and rarely arthropods. About 75% of emerging human infectious viruses are due to zoonosis, which means spread of virus from animals or insects to humans. Viruses generally reside in nose, throat, upper or lower respiratory system and also attacks gastrointestinal, nervous and reproductive systems of the host. Common viral reservoirs include: deer, rat, pigs, bats, boar, mangoose, camel, goat, ferret, rabbit etc.

Figure 1: Animal to human viral transfer

Spread of virus:

  • Unprocessed foods
  •  Uncooked meat – zoonotic viral reservoirs
  • Infectious air droplets that spread through air
  • Poor personal sanitization and hospital environment
  • Unsterilized hospital equipment
  • Insect/animal bite
  • Sexual transmission
Figure 2: Common viral diseases symptoms.

Major types of viral diseases were stated in the following table with all the information like – symptoms, mode of transmission, treatment, prevention along with the examples.

Type of viral diseaseSymptomsMode of transmissionTreatmentPreventionExamples
Gastrointestinal viral disease: Virus attacks digestive system of the host and lead to inflammation of stomach and small intestine called gastroenteritis. .-Abdominal cramps -Diarrhea -Vomiting-Food/water contaminated with virus containing feces. -sharing objects infected with the virus-Intake of lots of water to prevent dehydration because of vomiting/diarrhea-Proper sterilization of cooking utensils. -Disinfection of surroundings -Proper washing of hands before food intake and after toilet usage-Rotavirus -Norvovirus – Astrovirus
Respiratory viral disease: Virus that invades nose, throat, upper air ways and deep lungs-Cough -Cold -Runny nose -Fever Body pains-Droplets of cough and sneeze. -Contaminated objects with contagious droplets like door knobs etc-Over the counter medication like pain relievers, cough suppressants, decongestants, antiviral drugs  -Personal hygiene -Social distance -Covering mouth face during cough and sneeze-Influenza virus -Common cold -Respiratory syncytial virus -Severe acute respiratory syndrome (SARS) – SARS-CoV-2  
Hepatic viral disease: Virus that infects liver and cause inflammation -Bodily fluids – Viral infected objects -Contaminated food/water-Anti viral drugs -Intake of fluids-Vaccination – No sharing of blades/razors – Safe sex-Hepatitis A – Hepatitis B -Hepatitis C
Neurologic viral disease: Virus that infects brain and associated systems-Fever -Drowsiness -Seizures -Confusion-Infected animal/insect -Contaminated objects-Rest -Intake of fluids -Anti inflammatory drugs-Proper rest -Intake of fluids – Anti-inflammatory drugs-Polio -Rabies -Viral Encephalitis -Viral meningitis
Exanthematous viral disease: Virus that causes skin rashes  -Fever -Body pains-Droplets of cough and sneeze. -Contact with infectious skin lesions -Mosquito bite (Chickun gunya virus)-Fever reducing medication -Pain relievers-Vaccination – Protecting from viral vectors (mosquitoes)-Measles – Rubella -Chicken pox -Chikun gunya

Treatment to viral diseases:

Most viral symptoms are mild and go away in a few days in most of the people. Only a few, with weak immune system suffers. Treatment against viral diseases comprise mainly of over-the-counter medications to relieve symptoms, subside cold or cough irritations. Drinking plenty of fluids – to keep hydrated, self isolation – to prevent spread of the virus, act as effective as a drug. Not a single antiviral medication is effective against viruses. Anti viral medicines act on viruses by preventing – viral entry into host cells, viral DNA/RNA replication, viral machinery assembly and spread. However, anti viral drugs are effective when taken during the early onset of infection or during outbreak of virus in a particular season.

Viral vaccines:

Vaccines against viruses stimulate host’s immune system to be defensive against the invading virus. Viral vaccines include: measles/mumps/rubella, polio, hepatitis A, hepatitis B, chicken pox, human papillomavirus, rotavirus, yellow fever and other common viruses.

Over all, prevention is better than cure. Maintaining personal hygiene, minimal social contact, intake of healthy food, fully cooked meet are the best way to prevent the spread of viruses, both existing and the emerging ones.

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