Notes from the Field: Fatal Yellow Fever in a Traveler Returning From Peru — New York, 2016

Alexandra P. Newman, DVM1; Rebecca Becraft2; Amy B. Dean, PhD3; Rene Hull3; Bryon Backenson, MS1; Gillian Hale, MD4; Janeen Laven5; Julu Bhatnagar, PhD4; J. Erin Staples, MD, PhD5 (View author affiliations)

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In October 2016, a male New York resident aged 74 years developed fever, myalgia, nausea, and vomiting while traveling in Peru, 3 days after visiting the northern Amazon area. During the next 2 days, he experienced fever, abdominal pain, and watery diarrhea and was admitted to a hospital in Peru, where Entamoeba histolytica was detected in his stool. He was treated with intravenous fluids and antibiotics and released 1 day after admission. His condition worsened, however, and he returned to New York and immediately sought care at a hospital emergency department, where he was found to be afebrile, slightly confused, and jaundiced. Laboratory tests revealed leukopenia, thrombocytopenia, acute renal failure, liver dysfunction, and a metabolic acidosis (Table). He was transferred from the emergency department to a tertiary care center, where he was admitted and received intravenous fluids, antibiotics, and hemodialysis. During the next 2 days, he developed melena and disseminated intravascular coagulation. He experienced multiple episodes of ventricular fibrillation and died 3 days after admission. Autopsy revealed gastrointestinal hemorrhage and subtotal hepatocellular necrosis. Testing for selected viral, bacterial, and parasitic agents was negative, except for antibody to Salmonella H type A/B (Table). He had not received yellow fever vaccine before traveling. Serum specimens and tissues were sent to Wadsworth Center, the New York State Public Health Laboratory, and CDC to test for yellow fever virus and other pathogens.

A serum specimen collected 7 days after illness onset tested positive for flaviviral RNA by reverse transcription–polymerase chain reaction (RT-PCR), and the amplicon sequencing was consistent with yellow fever virus. A serum specimen obtained at autopsy was positive for yellow fever immunoglobulin M antibodies. Yellow fever RT-PCR assays performed on RNA extracted from formalin-fixed, paraffin-embedded liver tissue were positive; amplicon sequence analysis revealed highest identity with wild-type yellow fever virus strains. An immunohistochemical assay for yellow fever virus performed on the liver tissue demonstrated staining of necrotic hepatocytes throughout the lobules, without mesenchymal staining. The morphologic features of fulminant active hepatitis and the immunohistochemical staining pattern and sequencing results, in combination with the patient’s travel history to a region of Peru where yellow fever is endemic, lack of yellow fever vaccination, and clinical history supported the diagnosis of infection with wild-type yellow fever virus (1).

Yellow fever is a mosquitoborne viral disease endemic to sub-Saharan Africa and tropical areas of South America. Most infections are asymptomatic or result in a nonspecific febrile illness. The severe form of yellow fever results in jaundice and hemorrhage; approximately 50% of severe cases are fatal (2).

During 1970–2015, 11 yellow fever cases were reported among U.S. and European travelers (3). Before the current case, the last yellow fever case diagnosed in a U.S. resident was in 2002 (4). However, after large outbreaks in Africa and South America during 2016–2017, the number of cases confirmed in travelers from countries without endemic yellow fever transmission increased substantially, including at least 11 workers infected in Angola; two travelers in Peru; one each in Suriname and Bolivia; and this case (5,6).

No specific treatment for yellow fever exists; care is based on symptoms. Prevention of infection is through vaccination and avoidance of mosquito bites. Yellow fever vaccine is recommended for persons aged ≥9 months who are traveling to or living in areas at risk for yellow fever virus transmission (3). However, because serious adverse events can occur after yellow fever vaccination, contraindications and precautions to vaccination, such as patient age, should be considered before administering the vaccine. Health care providers should consider and test for yellow fever in unvaccinated persons with fever and jaundice or hemorrhage who live in or have traveled to an area with yellow fever virus transmission. Information on current yellow fever outbreaks and vaccination requirements and recommendations for specific countries are available on CDC Travelers’ Health website (

Conflict of Interest

No conflicts of interest were reported.

Corresponding author: Alexandra Newman,

1New York State Department of Health; 2Chemung County Health Department, Elmira, New York; 3Wadsworth Center, New York State Department of Health; 4Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, CDC; 5Division of Vector-borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, CDC, Ft. Collins, Colorado.


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Return to your place in the textTABLE. Clinical laboratory results* and infectious disease test results for patient with a fatal case of yellow fever — New York, 2016
Laboratory test Result Reference range
White blood cell count 3,600 3,800–10,600/μl
Platelet count 5,300 150,000–400,000/μl
Bicarbonate 10 22–303 mmol/L
Sodium 135 134–145 mmol/L
Potassium 5.7 3.5–5.1 mmol/L
Blood urea nitrogen 151 9–20 mg/dL
Creatinine 13.7 0.8–1.5 mg/dL
Alanine amino transferase 3,584 21–72 U/L
Aspartate amino transferase 3,596 17–59 U/L
Total bilirubin 11.8 0.0–1.0 mg/dL
Alkaline phosphatase 349 38–126 U/L
Albumin 3.4 3.5–5.0 g/dL
Lactic acid 3.6 0.7–2.1 mmol/L
Bacterial cultures (blood) No growth No growth
Leptospiral DNA (urine) Not detected Not detected
Dengue viral RNA (serum) Not detected Not detected
Salmonella H type A/B antibodies (serum) Positive Negative
Q fever antibodies (serum) Negative Negative
Hepatitis A virus antibodies (serum) Nonreactive Nonreactive
Hepatitis B virus antibodies (serum) Nonreactive Nonreactive
Hepatitis C virus antibodies (serum) Nonreactive Nonreactive
Yellow fever virus immunoglobulin M antibodies Positive Negative
Yellow fever virus neutralizing antibodies 640 <10

* Upon hospital admission.
Outside the reference range.

Suggested citation for this article: Newman AP, Becraft R, Dean AB, et al. Notes from the Field: Fatal Yellow Fever in a Traveler Returning From Peru — New York, 2016. MMWR Morb Mortal Wkly Rep 2017;66:914–915. DOI: icon.

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