Subscribe to Email Updates

The influence that Viruses have on symptoms/diseases in the human body


Dengue Virus

Dengue virus is responsible for causing a disease known as dengue fever. This viral infection continually poses a threat to the lives of people living in the tropical and sub-tropical regions of the world [1, 2]. The virus is transmitted by mosquitoes (Aedes aegypti), and effective control is to eliminate mosquitoes from the region having dengue fever incidents.

Dengue fever is associated with a severe headache and pain in either of the two including eye, joint, muscle besides rashes and bleeding. The viral infections also lead to decrease in the number of platelets count. Unfortunately, there is no effective approved vaccine or antiviral for controlling dengue fever. Only palliative measures and immune boosting strategies help in patient recovery.

Ebola Virus

This virus causes a disease which is known as Ebola hemorrhagic fever. This is a highly dangerous virus, and person to person transmission is mainly through bodily secretions of an infected human or sometimes animals bites. The virus is supposed to be transmitted from bats. In recent past, an Ebola outbreak and associated deaths in West Africa manifested the morbidity and mortality associated with this viral infection.

According to the Center for Disease Control (CDC) reports among ~28000 cases there were 11000 reported deaths as of April 13, 2016 [3]. Upon acquiring infection onset of symptoms is very rapid. It starts with a headache and sore throat leading to extreme internal and external bleeding and further progresses to multiple organ failures leading to ultimate death. 

Hepatitis Viruses

There are five different viruses causing hepatitis among human, i.e. Hepatitis A -E, however, among these Hepatitis caused by virus type A, B, and C are most prevalent [4]. The Hepatitis A is transmitted through fecal-oral routes, person to person contact, besides viral contaminated food and water. Hepatitis B is spread through bodily secretions including blood, semen, and other fluids, whereas the most common Hepatitis C is only transmitted through blood.

All these three and the other two D and E are responsible for causing inflammation of the liver leading to failure of this vital body organ. Hepatitis viruses are affecting the lives of millions, and several ongoing strategies are being used to control disease mainly the Hepatitis C.

Human Immunodeficiency Virus (HIV)

The HIV is responsible for causing a disease known as Acquired Immunodeficiency Syndrome (AIDS). This virus destroys the human body immune system mainly the CD4 positive T cells exposing the victim to several others diseases and infection. Unlike other viruses, it is impossible to get rid of this virus once a person is infected with the virus integrated into the human genome.

The viral transmission is through body secretions including blood and semen. This virus is mainly recognized as a sexually transmitted virus. Unfortunately, there is no cure for the viral disease; only the highly active antiretroviral therapy can keep a check on the disease and is considered as a standard treatment.

The viral infection associated neurological ailments known as AIDS dementia complex has been a major problem for the people who are infected with this virus. Efforts are ongoing to find an effective vaccine.

Influenza Virus

Influenza virus infection is the most common among humans. The relative recovery from this viral infection is fast as an individual immune system control the disease. However, we have to remember the “Spanish flu” a viral infection that killed 50 million people and created enormous morbidity [5, 6]. Recent events of bird flu and Middle East Respiratory Syndrome Virus (MERS) also belong to influenza viruses’ family [7-10].

In human, there are four types of seasonal influenza viruses, and new species keep emerging. The transmission of the flu virus is mainly through coughing, sneezing, touch and so on. The infection is manifested as fever, cough, sore throat, muscles and body aches besides fatigue.


The poliovirus causes a debilitating disease among children. The virus has the capability to transfer into the brain and damage the neurons thus leading to paralysis and deformities. Other symptoms associated with poliovirus are a sore throat, headache, stomach pain and lethargic conditions. This virus is highly contagious in nature and people mainly acquire this infection through person-to-person contact. Transmission is through fecal-oral routes and less common through sneezing or coughing [11].

An efficient and effective poliovirus vaccine is available, and mass vaccination is ongoing to eradicate this disease altogether. Except few, several countries have declared as polio free. The World Health Organization is very hopeful about overcoming this viral infection [12]

Rabies Virus

Rabies is a virus known to mankind since ancient times. This virus is transmitted by the bite of an infected animal to human although new studies suggest viral infection transmission through other routes also [13, 14]. The development of a vaccine for this virus although resulted in the decline of its occurrence but it’s still present in developing countries.

The pathogenesis of this virus is mediated through its entry into the central nervous system (CNS). The disease caused by this virus can be treated by vaccines. However, if it is left untreated, it is fatal without a doubt. Dogs are the most common source of this infection and an encounter with an infected dog can lead to a life threatening condition.  


This virus has a wheel like structure, and hence the name rotavirus was used on its discovery. It causes significant morbidity and mortality among infants and children. The viral transmission is through fecal-oral routes. The virus mainly damages the intestinal linings through leading to excessive fluid losses thus causing dehydration as a primary manifestation. Several antibiotics and alternative treatments are used for controlling the disease [15]. Major defining symptoms of rotavirus infection are vomiting and diarrhea.

This virus is considered as the leading cause of diarrheal illness among young children. The availability of a vaccine against this virus has significantly reduced its occurrence, but the infection resulting from these infections are still a major killer in developing countries where there is no proper rehydration treatments and vaccine available [16].

Smallpox virus

The Smallpox virus causes a disease known as smallpox that no longer exists on this Earth. Historical records show that smallpox virus disease used to be present in 300 BC. Thanks to an effective vaccine and appropriate vaccination strategies that helped in eradicating this disease from this Earth. It is important to describe here that this virus used to be transmitted by prolonged facial contacts between people.

Generally, the symptoms of this disease were fever, rash, raised fluid filled blisters or oozing pustules that developed on the skin. The disease manifestation was small sores all across the body and upon acquiring the first sore the infected person used to be highly contagious till he completely recovers from the illness [7].

Zika virus

The Zika virus infection is associated with a disease hindering the development of the brain in fetus leading to a condition known as microcephaly. This viral infection is transmitted by two mosquito species Aedes aegypti and Aedes albopictus and is associated with initial symptoms like fever, rash, muscular pains, and headache.

Pregnant women are at major risk of transmitting Zika to their fetus as the virus can transmit through the barrier protecting the baby in mother womb [17]. The virus basically stops all the ongoing brain tissue growth, and the newborn usually have a head circumference smaller than non-infected infants. There were several recent outbreaks of the Zika virus [18, 19].

Professor Dr. Muhammad Mukhtar


1. Cucunawangsih and N.P.H. Lugito, Trends of Dengue Disease Epidemiology. Virology (Auckl), 2017. 8: p. 1178122X17695836.

2. Sharp, T.M., et al., A New Look at an Old Disease: Recent Insights into the Global Epidemiology of Dengue. Curr Epidemiol Rep, 2017. 4(1): p. 11-21.

3. CDC, 2014-2016 Ebola Outbreak in West Africa., 2017.

4. Chak, E.W., S. Sarkar, and C. Bowlus, Improving Healthcare Systems to Reduce Healthcare Disparities in Viral Hepatitis. Dig Dis Sci, 2016. 61(10): p. 2776-2783.

5. Borza, T., [Spanish flu in Norway 1918-19]. Tidsskr Nor Laegeforen, 2001. 121(30): p. 3551-4.

6. Gottfredsson, M., [The Spanish flu in Iceland 1918. Lessons in medicine and history]. Laeknabladid, 2008. 94(11): p. 737-45.

7. Virology: What makes bird flu jump species? Nature, 2017. 543(7647): p. 593.

8. Lakoff, A., A fragile assemblage: Mutant bird flu and the limits of risk assessment. Soc Stud Sci, 2017. 47(3): p. 376-397.

9. Rabaan, A.A., et al., Molecular aspects of MERS-CoV. Front Med, 2017.

10. Widagdo, W., et al., MERS-coronavirus: From discovery to intervention. One Health, 2017. 3: p. 11-16.

11. Martinez-Bakker, M., A.A. King, and P. Rohani, Unraveling the Transmission Ecology of Polio. PLoS Biol, 2015. 13(6): p. e1002172.

12. Global polio eradication: progress towards containment of poliovirus type 2, worldwide 2017. Wkly Epidemiol Rec, 2017. 92(25): p. 350-6.

13. Gong, C., et al., Rabies transmission following organ transplantation in China. J Infect, 2017. 74(4): p. 427-431.

14. Ruan, S., Modeling the transmission dynamics and control of rabies in China. Math Biosci, 2017. 286: p. 65-93.

15. Gonzalez-Ochoa, G., et al., Modulation of rotavirus severe gastroenteritis by the combination of probiotics and prebiotics. Arch Microbiol, 2017.

16. Kotirum, S., et al., Global economic evaluations of rotavirus vaccines: A systematic review. Vaccine, 2017. 35(26): p. 3364-3386.

17. Duarte, G., et al., Zika Virus Infection in Pregnant Women and Microcephaly. Rev Bras Ginecol Obstet, 2017. 39(5): p. 235-248.

18. Berenson, A.B., et al., Knowledge and Prevention Practices among U.S. Pregnant Immigrants from Zika Virus Outbreak Areas. Am J Trop Med Hyg, 2017. 97(1): p. 155-162.

19. Garcia Serpa Osorio-de-Castro, C., et al., The Zika Virus Outbreak in Brazil: Knowledge Gaps and Challenges for Risk Reduction. Am J Public Health, 2017. 107(6): p. 960-965.

Topics: Viruses

Professor Dr. Muhammad Mukhtar

Written by Professor Dr. Muhammad Mukhtar

Professor Dr. Muhammad Mukhtar has over 25 years teaching experience in biomedical sciences. Besides teaching, he has a very strong portfolio of academic administration and he is an accomplished researcher in the area of infectious diseases. Dr. Mukhtar received his Ph.D. in Biosciences from the Drexel University of Philadelphia, USA, and also completed a Graduate Certificate in Research Management from Thomas Jefferson University of Philadelphia, USA. He served in various academic/administrative positions in the USA on an outstanding scientist (O-1) visa.