Comparative Studies of Ebola, Influenza, HIV and Zika Viruses Paper Example

Introduction

There are different viruses that can affect the health of people in society such as HIV and Zika. It is important to understand their properties and pathogenesis to determine how risky they are on human health. Below is a comparative study of HIV, Influenza, Zika and Ebola viruses on their structure and properties, pathogenesis and epidemiology.

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Structure and Properties

Zika virus is a virus within the Flaviviridae family. Its genome is a single-stranded RNA while the proteome is a single polyprotein approximately 11kb long. The genome has an open reading frame which encodes 7 nonstructural proteins and 3 structural proteins. The non-structural proteins take part in viral replication while the structural proteins take part in the pathogenicity and viral assembly (Nitatpattana et al., 1). Zika virus has a coat of associate membrane proteins and Envelope proteins on the outer surface which enables it to survive in the environment. The virus has about 12 to 25 mutations annually.

Ebola virus is a single-stranded genome RNA virus. It is 80nm wide and has a glycoprotein that is 7 to 10nm long (Beniac and Booth, para 2). The virus cannot replicate on its own as it is an enveloped virus. It leaves with part of the host cell's membrane when leaving a cell. It has one non-structural protein and seven structural proteins. The Ebola virus mutates after every 9.5 days hence has a high mutation rate.

Influenza is an enveloped virus that has glycoproteins. It has rapid mutations of 7.1 x 10-6 per nucleotide in every cell which make it hard to develop vaccines. The virus is about 80 to 120 nm in diameter. Its viral RNA is negative-stranded and has to be copied into positive strands to act as a protein template (Noda and Kawaoka, 8797). Influenza A and B genomes have 8 pieces of single-stranded RNA while influenza C has 7 strands of RNA. Neuraminidase and hemagglutinin are the proteins that take part in the attachment of the virus to a host cell.

HIV virus is within the Retroviridae family and has two identical single-stranded RNA particles. It has a high mutation rate of 4 x 10 -3 per base in each cell. The genetic material of HIV in the center is single-stranded RNA while a viral nucleocapsid protein encloses it on the outside (LI and De Clercq, 681). The virus is about 100 nm in diameter. Transmembrane protein and surface protein envelope the mature HIV particle and assist in replication.

Pathogenesis

When the Zika virus enters a person's body, it infects the cells and evades any detection in the immune system. Some of the organs that are attacked by the virus include reproductive tracts, skin, and eyes (Nayak et al., 267). Most people infected with the virus do not develop symptoms, however, there are mild symptoms such as headaches, joint pains, muscle pains, fever, conjunctivitis and rash seen in the first two to seven days (WHO c, para 6). The main areas in the body affected by the virus are the brain and immune system. Zika mortality rates are rare hence low (Beckham et al., 877).

Ebola virus has an incubation period of 2 to 21 days before the onset of symptoms. Its symptoms include diarrhea, vomiting, rash as well as internal and external bleeding. The virus affects the immune organs and systems (Falasca et al., para 26). The internal and external bleeding occurs inside a person's body, eyes, nose, and ears. Some of the organs attacked by the virus include the liver, lungs, and kidneys.

The Influenza virus affects the respiratory system which comprises of the throat, nose, and tubes leading to the lungs (WHO a, para 2). The virus mainly affects the epithelial cells. Its symptoms include a sore throat, phlegmy cough, and runny nose. In some cases, people have headaches and muscle aches.

The HIV virus affects the immune system and different organs such as the liver, heart, brain, eyes, bones, and kidneys. A HIV infected person has symptoms such as a sore throat, diarrhea, night sweats, joint pain, headache, fatigue, and swollen lymph glands. The main cell affected by the virus is the CD4 helper cell whose role is fighting off infections.

Epidemiology

Zika virus is transmitted through infected Aedes mosquitoes to a human being (WHO c, para 2). It is also transmitted through transfusion of blood products, sexual contact or mother to fetus during pregnancy. According to the World Health Organisation (WHO), 86 countries have reported evidence of Zika virus in their regions. The virus has low report cases as in 2017 there were 452 Zika virus cases reported in the US while the US territories reported 666 cases (CDC c, para 2). The mortality rate of the virus is about 8.3%.

People acquire Ebola from infected animals such as gorillas, chimpanzees, porcupines, and fruit bats and later spread to humans through human to human transmission. It is transmitted through secretions, blood and bodily fluids from infected people (CDC a, para 5). Direct contact with material and surfaces with contaminated fluids such as bedding and clothing also leads to transmission of the virus. Ebola outbreaks differ every year as there are years with close to no Ebola cases, however, there are years with high cases due to Ebola outbreak. For instance, there were 8 reported cases in 2017 and about 28,000 reported cases in 2014 (CDC b, para 3). The mortality rate of Ebola is high as up to 79% of infected people lose their lives.

The Influenza virus is transmitted through direct contact with contaminated objects, infected individuals and inhaling aerosols that are virus-laden. Based on World Health Organisation, influenza leads to 3 to 5 million cases annually and 290 000 to 650 000 deaths (WHO a, para 4).

The HIV virus is transmitted through vaginal fluid, semen, blood and breast milk. In 2017, there were 1.8 million new HIV cases and the total number of people living with HIV in the year was 36.9 million. WHO reported that about 940 000 people died from HIV in 2017 globally. The rate is reducing as it was 34% more in 2010 (WHO b, para 1).

Conclusion

HIV is a non-contagious infection which results to about 1.8 million infections annually. ZIka virus is a non-contagious infection that causes about 452 infections annually. Influenza virus is contagious and causes about 3 million cases annually. Ebola virus is contagious and causes about 28,000 new infections annually. Zika, Ebola, Influenza, and HIV have high mutation rates hence have high abilities to mutate. The mortality rate of Zika is low at about 8.3% while that of Ebola virus is 79% hence high. HIV has a high mortality rate of 940 000 deaths annually while Influenza causes about 650 000 deaths annually. Ebola and Zika virus have low outbreaks annually compared to HIV and Influenza. Among the four viruses, HIV is the most dangerous to the human population as it infects a high number of people and leads to more deaths compared to the other viruses.

Works Cited

Beckham, J. David, Beckham, J. David, Daniel M. Pastula, Aaron Massey, and Kenneth L. Tyler. "Zika virus as an emerging global pathogen: neurological complications of Zika virus." JAMA neurology 73.7 (2016): 875-879.

Beniac, Daniel R., and Timothy F. Booth. "Structure of the Ebola virus glycoprotein spike within the virion envelope at 11 A resolution." Scientific reports 7 (2017): 46374.

CDC a. "History of Ebola Virus Disease | 2014-2016 Outbreak West Africa | History | Ebola (Ebola Virus Disease) | CDC". Cdc.Gov, 2018, https://www.cdc.gov/vhf/ebola/history/summaries.html.

CDC b. "Years of Ebola Virus Disease Outbreaks | 2014-2016 Outbreak West Africa | History | Ebola (Ebola Virus Disease) | CDC". Cdc.Gov, 2018, https://www.cdc.gov/vhf/ebola/history/chronology.html.

CDC c. "Zika Virus 2017 Case Counts In The US". CDC, 2018, https://www.cdc.gov/zika/reporting/2017-case-counts.html.

Falasca, L., C. Agrati, N. Petrosillo, A. Di Caro, M. R. Capobianchi, G. Ippolito, and M. Piacentini. "Molecular mechanisms of Ebola virus pathogenesis: focus on cell death." Cell death and differentiation 22.8 (2015): 1250.

Li, Guangdi, and Erik De Clercq. "HIV genome-wide protein associations: a review of 30 years of research." Microbiology and Molecular Biology Reviews 80.3 (2016): 679-731.

Nayak, Shriddha, Jun Lei, Andrew Pekosz, Sabra Klein, and Irina Burd. "Pathogenesis and molecular mechanisms of Zika virus." Seminars in reproductive medicine. Vol. 34. No. 05. Theme Medical Publishers, 2016.

Nitatpattana, Narong, Nitatpattana, Narong, Kumchol Chaiyo, Supoth Rajakam, Kanya Poolam, Kusuma Chansiprasert, Norapath Pesirikan, Supanat Buree, Ekkarat Rodpai, and Sutee Yoksan. "Complete Genome Sequence of a Zika Virus Strain Isolated from the Serum of an Infected Patient in Thailand in 2006." Genome announcements 6.10 (2018): e00121-18.

Noda, Takeshi, and Yoshihiro Kawaoka. "Packaging of influenza virus genome: robustness of selection." Proceedings of the National Academy of Sciences 109.23 (2012): 8797-8798.

WHO a. "Influenza (Seasonal)". World Health Organization, 2018, http://www.who.int/news-room/fact-sheets/detail/influenza-(seasonal).

WHO b. "Number of Deaths Due to HIV/AIDS". World Health Organization, 2018, http://www.who.int/gho/hiv/epidemic_status/deaths_text/en/.

WHO c. "Zika Virus". World Health Organization, 2018, http://www.who.int/en/news-room/fact-sheets/detail/zika-virus.