Yellow Fever

Reportable by Providers and Laboratories

About this Reportable Disease

Infectious agent:  Yellow Fever Virus is an RNA virus that belonging to the genus Flavivirus.

Description of illness: The majority of persons infected with yellow fever virus have no illness or only mild illness. In persons who develop symptoms, the incubation period (time from infection until illness) is typically 3–6 days. The initial symptoms include sudden onset of fever, chills, severe headache, back pain, general body aches, nausea, and vomiting, fatigue, and weakness. Most persons improve after the initial presentation. After a brief remission of hours to a day, roughly 15% of cases progress to develop a more severe form of the disease. The severe form is characterized by high fever, jaundice, bleeding, and eventually shock and failure of multiple organs. No specific treatments have been found to benefit patients with yellow fever. Whenever possible, yellow fever patients should be hospitalized for supportive care and close observation. Treatment is symptomatic. Rest, fluids, and use of pain relievers and medication to reduce fever may relieve symptoms of aching and fever.

Laboratory Reporting for this Disease

Reporting requirements apply to all laboratories located within Tennessee, as well as laboratories outside of Tennessee that test residents of Tennessee, including laboratories located within healthcare facilities. Healthcare providers and laboratories in the same healthcare facility both have a duty to report. The type of organisms and analytes laboratories must report to TDH for 2026 are indicated, and there are several ways laboratories can report results to TDH.

Information about this Reportable Disease for Healthcare Providers

Clinical Summary

  • Scope and agent: Yellow fever is an acute viral hemorrhagic disease caused by the yellow fever virus, a mosquito-borne flavivirus. It is endemic in parts of sub-Saharan Africa and tropical South America.
  • Clinical presentation: Illness ranges from a nonspecific febrile syndrome (fever, headache, myalgia, nausea/vomiting) to severe disease characterized by jaundice, hepatitis, hemorrhage, renal failure, and shock. After initial improvement, some patients progress to a toxic phase with multisystem involvement. Case fatality is high among patients who develop severe disease.
  • Transmission and epidemiology: Transmitted through the bite of infected mosquitoes (Aedes and Haemagogus species). Occurs in jungle (sylvatic), intermediate, and urban transmission cycles. Not spread by casual person-to-person contact.
  • Clinical approach: Consider in patients with acute febrile illness and jaundice who have recent travel to or residence in endemic areas. Obtain travel history and assess vaccination status. Laboratory confirmation requires specialized testing (e.g., serology or PCR) coordinated with public health authorities.
  • Treatment and prevention: No specific antiviral therapy; management is supportive. Prevention relies on mosquito avoidance and vaccination. The yellow fever vaccine is highly effective and required for entry into some countries.
  • Reporting: Yellow fever is nationally notifiable. Immediately report suspected cases to public health authorities to facilitate testing and response.

Healthcare Provider Reporting

Healthcare reporting requirements apply to all providers located within Tennessee, as well as providers whose patients reside in Tennessee.

Providers must report cases of all diseases and conditions listed through one of these methods:

• Mail or fax a completed PH-1600 form to your local health department or fax to the state health office at (615) 741-3857

• Send automatically via electronic case reporting (eCR). See this TDH webpage for more information on eCR, register at the Trader Partner Registration website, or contact MU.Health@tn.gov for assistance.

• Submit online via NBS. NBS is TDH's reportable disease system. To request an NBS account for reporting Complete this user survey to request an NBS account for reporting. 

• Blood lead levels can be sent via fax ( (615) 741-3857), entered online, or reported using the instructions at this link. 

Information about this Reportable Disease for the Public

What It Is

Yellow fever is a viral disease transmitted to humans by infected mosquitoes, primarily in tropical and subtropical regions of Africa and South America. It belongs to the genus Flavivirus, similar to dengue and West Nile viruses. It can range from a mild febrile illness to a severe hemorrhagic form affecting multiple organs. Because there is no specific antiviral therapy, prevention (especially vaccination and mosquito control) is essential. 

Types

Yellow fever virus cycles in nature via three main transmission modes: sylvatic (jungle), intermediate (savannah), and urban. In the sylvatic cycle, forest mosquitoes transmit the virus between non-human primates (e.g., monkeys) and, occasionally, humans entering the jungle. The intermediate (or savannah) cycle involves semi-domestic mosquitoes that infect both monkeys and humans, common in rural Africa. The urban cycle is driven by Aedes mosquitoes, which transmit the virus between humans, enabling large outbreaks in densely populated areas. 

Signs and Symptoms

After an incubation period of about 3 to 6 days, many infections remain asymptomatic. When symptoms appear, they often begin abruptly with fever, chills, severe headache, back pain, muscle aches, nausea, vomiting, fatigue, and weakness. Most recover within a week, but in about 15% of symptomatic patients, the disease enters a more toxic phase.  In the severe form, high fever recurs, and patients may develop jaundice (yellowing of skin and eyes), dark urine, abdominal pain, bleeding (e.g., from mouth, nose, GI tract), renal impairment, shock, and multi-organ failure; fatality among severe cases can reach 30-60%.

Treatment

There is no specific antiviral treatment for yellow fever; care is largely supportive.  Mild cases are managed with rest, hydration, and use of antipyretics and analgesics (avoiding NSAIDs that may increase bleeding risk).  Patients with severe disease should be hospitalized for close monitoring and supportive care (e.g., management of bleeding, shock, renal or hepatic failure).  Blood products, dialysis, and intensive care may be needed depending on complications.  Prevention is critical: vaccination before travel or residence in endemic zones, and rigorous mosquito bite avoidance. 

This Page Last Updated: March 25, 2026 at 8:53 PM