Yellow fever virus- is a spherical, enveloped virus with a single-stranded, positive- sense RNA genome. 

The main virulence factor is the surface macromolecules on yellow fever virus and it aids in the virus’s entry and cell interactions (11).

Remission This stage is lasts around 48 hours. Fever and of the symptoms usually start to go away. Most people recover during this phase. The virus could still be present in the patient’s bloodstream, but typically starts to diminish (9)

Intoxication About 15-25 % of people enter a more toxic
stage within 24 hours of recovering from the infection stage. Usually can last for 3-8 days. Common signs/symptoms of this stage are: fever, bradycardia, vomiting, nausea, epigastric pain, jaundice- yellowing of the skin and eyes, oliguria and hemorrhaging, dark urine, abdominal pain and bleeding from the mouth, nose, eyes or stomach. Many patients will suffer from multi-organ failure which can be hepatic, renal, hematological and cardiovascular associated. Half of these patients usually die within 7-10 days (9).

                         

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The virus then starts to replicate locally and is then transported to the rest of the body via the the lymphatic system

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The virus proceeds to dominate throughout multiple organ systems. Some of the organs affected are: the heart, kidneys, the adrenal glands, and liver. The body undergoes viremia- presence of virus in the blood. Necrotic masses begin to appear in hepatocytes (liver cells).

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The virus induces cell death of liver cells and other cells such as kidney cells. Cytokines cause hypotension and shock.

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This can lead to multiple organ failures in the body.

Haemagogus mosquitoes are the primary yellow fever virus vector in Southern Brazil and Aedes mosquitoes are a secondary vector.

In tropical rainforests, monkeys (the primary reservoir of yellow fever) are bitten by Aedes and Haemogogus species mosquitoes and then acquires the virus. Sometimes humans in tropical rainforests can be infected, but the virus is mainly passed on to monkeys by infected mosquitoes. 

Semi-domestic mosquitoes- mosquitoes that breed in the wild and households. Semi-domestic mosquitoes infect both monkeys and people. This is the most common type of outbreak in Africa.

Large epidemics occur when infected people carry the virus in areas with high population of Aedes mosquitoes and areas with high population of humans. They can also occur where most people have little/ no immunity (due to lack of vaccination). With these specific conditions, infected mosquitoes are able to transmit the virus from human to human.

Most people recover, but it can take months or even years. In some cases, the damage to the liver and kidney could be reversed. Internal bleeding can occur and in some severe cases, death is a possible outcome. Yellow fever can cause severe complications and illness.

There is currently no medicines to treat or cure yellow fever, however, the best way to prevent yourself from getting it is to get vaccinated.

Banluta, C. “Yellow Fever.” World Health Organization (WHO), (n.d.), https://www.who.int/health-topics/yellow-fever#tab=tab_1. Accessed 20 November 2022.

Centers for Disease Control and Prevention. “Yellow Fever Virus.” CDC, 2021, https://www.cdc.gov/yellowfever/index.html. 

Legg, Timothy J., and Alana Biggers. “Yellow Fever: Symptoms, causes, and prevention.” Medical News Today, 2017, https://www.medicalnewstoday.com/articles/174372#symptoms.

1. Yellow Fever, (n.d.), https://www.gov.mb.ca/health/publichealth/cdc/protocol/yellow.pdf. Accessed 20 November 2022.

2. Banluta, C. “Yellow Fever.” World Health Organization (WHO), (n.d.), https://www.who.int/health-topics/yellow-fever#tab=tab_1. Accessed 20 November 2022.

3. Centers for Disease Control and Prevention. “Yellow Fever Virus.” CDC, 2021, https://www.cdc.gov/yellowfever/index.html. Accessed 20 November 2022.

4. Legg, Timothy J., and Alana Biggers. “Yellow Fever: Symptoms, causes, and prevention.” Medical News Today, 2017, https://www.medicalnewstoday.com/articles/174372#symptoms. Accessed 20 November 2022.

5. National Library of Medicine. “Yellow Fever and Cardiovascular Disease: An Intersection of Epidemics.” NCBI, (n.d.), https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5898767/. Accessed 20 November 2022.

6. National Library of Medicine. “Yellow Fever Virus in Haemagogus leucocelaenus and Aedes serratus Mosquitoes, Southern Brazil, 2008.” NCBI, 2010, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3294583/. Accessed 20 November 2022.

7. National Organization for Rare Disorders. “Yellow Fever - NORD.” National Organization for Rare Disorders, (n.d.), https://rarediseases.org/rare-diseases/yellow-fever/. Accessed 20 November 2022.

8. Pan American Health Organization. “Yellow Fever.” PAHO, (n.d.), https://www.paho.org/en/topics/yellow-fever. Accessed 20 November 2022.

9. Research Occupational Health Program. “Yellow Fever Virus Agent Information Sheet | Research Support.” Boston University, (n.d.), https://www.bu.edu/researchsupport/safety/rohp/agent-information-sheets/yellow-fever-virus-agent-information-sheet/. Accessed 20 November 2022.

10. Ryabov, Eugene V. “Factors Involved in the Apoptotic Cell Death Mechanism in Yellow Fever Hepatitis.” NCBI, 1 June 2022, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9227230/. Accessed 20 November 2022.

11. Sethman, Nathan Storey, and Tyrrell Conway. “Yellow Fever virus - microbewiki.” microbewiki, 11 February 2016, https://microbewiki.kenyon.edu/index.php/Yellow_fever_virus. Accessed 20 November 2022.