Skip to Content
800-533-8762
  • Careers
  • Newsroom
  • Health Care Professionals
  • About Us
  • Contact Us
UPMC
  • Find a Doctor
  • Services
    • Frequently Searched Services
    • Frequently Searched Services
      Allergy & Immunology Behavioral & Mental Health Cancer Ear, Nose & Throat Endocrinology Gastroenterology Heart & Vascular Imaging Neurosciences Orthopaedics
      Physical Rehabilitation Plastic & Reconstructive Surgery Primary Care Senior Services Sports Medicine Telemedicine Transplant Surgery Walk-In Care Weight Management Women’s Health
      See all Services
    • Services by Region
    • Find a UPMC health care facility close to you quickly by browsing by region.
      UPMC in Western Pa. Western Pa. and New York
      UPMC in Central Pa. Central Pa.
      UPMC in North Central Pa. North Central Pa.
      UPMC in Western Md. Maryland & West Virginia
    • See All Services
  • Locations
    • Locations by Type
    • Locations by Type
      UPMC hospitals
      Hospitals
      Physical Therapy
      Physical Therapy
      Urgent care
      Walk-In Care
      UPMC Outpatient Centers
      Outpatient Centers
      UPMC Imaging Services
      Imaging
      Community Health Centers
      Community Health Centers
      See All Locations
    • Locations by Region
    • Locations by Region
      UPMC in Southwest Pa. Southwest Pa.
      UPMC in North Central Pa. North Central Pa.
      UPMC in Northwest Pa and Ny. Northwest Pa. & Western N.Y.
      UPMC in West Central Pa. West Central Pa.
      UPMC in Central Pa. Central Pa.
      UPMC in Western Md. Maryland & West Virginia
    • See All Locations
  • Patients & Visitors
    • Patient & Visitor Resources
    • Patient & Visitor Resources
      Patients and Visitors Resources Pay a Bill Classes & Events Medical Records Health Library Patient Information
      Patient Portals Privacy Information Shared Decision Making Traveling Patients Visitor Information
      Man uses mobile phone
      Pay a Bill
      Nurse reviews medical chart
      Request Medical Records
  • Patient Portals
  • Find Covid-19 updates
  • Schedule an appointment
  • Request medical records
  • Pay a bill
  • Learn about financial assistance
  • Find classes & events
  • Send a patient an eCard
  • Make a donation
  • Volunteer
  • Read HealthBeat blog
  • Explore UPMC Careers
Skip to Content
UPMC
  • Patient Portals
  • For Patients & Visitors
    • Find a Doctor
    • Locations
    • Patient & Visitor Resources
    • Pay a Bill
    • Services
    • More
      • Medical Records
      • Financial Assistance
      • Classes & Events
      • HealthBeat Blog
      • Health Library
  • About UPMC
    • Why UPMC
    • Facts & Stats
    • Supply Chain Management
    • Community Commitment
    • More
      • Financials
      • Support UPMC
      • UPMC Apps
      • UPMC Enterprises
      • UPMC International
  • For Health Care Professionals
    • Physician Information
    • Resources
    • Education & Training
    • Departments
    • Credentialing
  • Careers
  • Contact Us
  • Newsroom
  • UPMC >
  • Our Services >
  • UPMC Center for Care of Infectious Diseases >
  • Conditions We Treat >
  • Sloth Fever
UPMC Center for Care of Infectious Diseases
Conditions We Treat
Antibiotic Resistance
Cellulitis
Clostridioides difficile (C. difficile or C. diff)
Coronavirus
Eastern Equine Encephalitis
Fungal Infections
HIV Infection and AIDS
Meningitis
Mpox (Monkeypox)
Necrotizing Fasciitis
Nontuberculous Mycobacteria
Osteomyelitis
Pneumonia
Respiratory Syncytial Virus Infection (RSV)
Sepsis
Sloth Fever
Tuberculosis and TB Screening
Our Services
Our Experts
Research and Training
Your Visit
Telemedicine
Contact Us
UPMC Center for Care of Infectious Diseases
Conditions We Treat
Antibiotic Resistance
Cellulitis
Clostridioides difficile (C. difficile or C. diff)
Coronavirus
Eastern Equine Encephalitis
Fungal Infections
HIV Infection and AIDS
Meningitis
Mpox (Monkeypox)
Necrotizing Fasciitis
Nontuberculous Mycobacteria
Osteomyelitis
Pneumonia
Respiratory Syncytial Virus Infection (RSV)
Sepsis
Sloth Fever
Tuberculosis and TB Screening
Our Services
Our Experts
Research and Training
Your Visit
Telemedicine
Contact Us

Chat Keywords List

  • cancel or exit: Stops your conversation
  • start over: Restarts your current scenario
  • help: Shows what this bot can do
  • terms: Shows terms of use and privacy statement
  • feedback: Give us feedback
Continue
Chat with UPMC
RESTART
MENU
CLOSE

Sloth Fever

Sloth fever, also known as the Oropouche virus, is an emerging virus that was reported in the United States in 2024. The virus is spread by infected biting midges and mosquitos.

Common symptoms include a fever, headaches, chills, and muscle and joint pain. Americans should prevent insect bites while traveling, and pregnant people may want to defer travel to areas experiencing outbreaks of sloth fever.


Looking for Sloth Fever Care?

Related services include:

  • Infectious Diseases

Find a Provider


On this page:

  • What Is Sloth Fever?
  • What Are the Symptoms of Sloth Fever?
  • How Do You Diagnose Sloth Fever?
  • How Do You Treat Sloth Fever?

What Is Sloth Fever?  

The Oropouche virus — also called sloth fever — was identified in late 2023 as the cause of large outbreaks in the Amazon region. The virus was then found in more areas of South America and in the Caribbean. Between January and August 2024, more than 8,000 cases were reported.

First detected in 1955 in Trinidad and Tobago, sloth fever is endemic in the Amazon basin, meaning it's common in that region. The current outbreak is happening in both endemic areas of the Amazon basin and in other countries, including Brazil, Bolivia, Colombia, Cuba, and Peru.

In summer 2024, travel-associated cases of Oropouche virus were found in Europeans returning from Brazil and Cuba. In August 2024, 21 sloth fever cases were found in U.S. travelers returning from Cuba.

Although infection usually causes a fever that resolves on its own, two people have died from the virus. In addition, concerns have been raised for pregnant people as five cases of fetal death or congenital abnormalities have been reported from sloth fever.  

What causes sloth fever?  

The virus is thought to involve certain vertebrate hosts, such as birds, nonhuman primates, and sloths. Biting midges and possibly mosquitoes sting the infected vertebrates and then sting humans, passing the virus on through the bite.

Can sloth fever be transmitted from person to person?

There's no documented evidence that sloth fever is spread through direct contact with infected people. It's spread through the bites of small biting flies called midges and certain mosquitoes.

What are sloth fever risk factors?  

Sloth fever risk factors  

Risk factors for contracting sloth fever include:

  • Traveling in the Amazon basin, affected countries in South America, or Cuba.
  • Getting bitten by a biting midge or mosquito while you’re there.

Sloth fever complications

The most serious complication of sloth fever is death. Two nonpregnant women died from their illnesses in the Brazil exposure. Other serious pregnancy complications were found in five cases, including fetal death and congenital abnormalities like microcephaly.

These deaths and associated adverse birth outcomes were the first reported serious complications of Oropouche virus.

How can I prevent sloth fever?

You can reduce your risk of contracting Oropouche virus by taking precautions while traveling in South America and the Caribbean.

Protect yourself from insect bites by:

  • Staying away from standing water where insects breed.
  • Treating clothing and gear with insect repellent.
  • Using an EPA-approved insect repellent.
  • Wearing long-sleeved, loose-fitting shirts and pants.

If you're pregnant, insect repellents containing DEET 50% are recommended at any stage of pregnancy if traveling to an outbreak area.

Back to top.


What Are the Signs and Symptoms of Sloth Fever?

Oropouche virus symptoms are similar to those of the chikungunya, dengue, and zika viruses. The incubation period is typically between three and 10 days.

Although illness is usually mild, people may experience a sudden onset of symptoms. Symptoms and their prevalence in people who get sloth fever include:

  • Abdominal pain (29%).
  • Back pain (19%).
  • Diarrhea (48%).
  • Fatigue (62%).
  • Fever (95%).
  • Headache (76%).
  • Joint pain (57%).
  • Mucosal bleeding (5%).
  • Muscle aches and pain (85%).
  • Nausea or vomiting (29%).
  • Rash (29%).
  • Retroorbital (behind the eye) pain (24%).

Sloth fever virus symptoms may also include light sensitivity, chills, bloodshot eyes, and rarely neuroinvasive issues, such as meningitis and meningoencephalitis. 

In addition, a recurrence of symptoms after the initial illness is common with sloth fever.

Back to top.


How Do You Diagnose Sloth Fever?  

Sloth fever is diagnosed by testing blood serum in the pathology laboratory. People with symptoms of neuroinvasive disease may receive a spinal puncture to have their cerebrospinal fluid (CSF) tested.

These tests can be done at some public health labs and at the Centers for Disease Control and Prevention (CDC). Both are working to develop new diagnostic tests for Oropouche virus to limit its spread and create a U.S. response plan.   

Back to top.


How Do You Treat Sloth Fever?  

The goal of Oropouche virus treatment is to manage the symptoms. No specific vaccines exist to prevent sloth fever, and no medications exist to treat it.  

The CDC is providing consultation and guidance to pregnant people and their health care providers. They're also tracking this and other emerging health threats to determine their impact on pregnant people and their newborns.

How effective is treatment?

Of the 21 Oropouche virus cases reported among U.S. travelers returning from Cuba in August 2024, most recovered with limited illness. At least three people experienced recurrent symptoms after the initial illness had resolved.

Back to top.

Additional Resources

  • What Is Sloth Fever (Oropouche Virus)? | UPMC HealthBeat

By UPMC Editorial Staff. Last reviewed on 2024-01-07 by Christiane Hadi, MD.

Health Alert Network (HAN) - 00515 | Increased Oropouche Virus Activity and Associated Risk to Travelers (cdc.gov)

Oropouche Virus Disease Among U.S. Travelers — United States, 2024 | MMWR (cdc.gov)
UPMC
200 Lothrop Street Pittsburgh, PA 15213

412-647-8762 800-533-8762

Patients And Visitors
  • Find a Doctor
  • Locations
  • Pay a Bill
  • Patient & Visitor Resources
  • Disabilities Resource Center
  • Services
  • Medical Records
  • No Surprises Act
  • Price Transparency
  • Financial Assistance
  • Classes & Events
  • Health Library
Health Care Professionals
  • Physician Information
  • Resources
  • Education & Training
  • Departments
  • Credentialing
Newsroom
  • Newsroom Home
  • Inside Life Changing Medicine Blog
  • News Releases
About
  • Why UPMC
  • Facts & Stats
  • Supply Chain Management
  • Community Commitment
  • Financials
  • Supporting UPMC
  • HealthBeat Blog
  • UPMC Apps
  • UPMC Enterprises
  • UPMC Health Plan
  • UPMC International
  • Nondiscrimination Policy
Life changing is...
Follow UPMC
  • Contact Us
  • Website/Email Terms of Use
  • Medical Advice Disclaimer
  • Privacy Information
  • Active Privacy Alerts
  • Sitemap
© 2025 UPMC I Affiliated with the University of Pittsburgh Schools of the Health Sciences Supplemental content provided by Healthwise, Incorporated. To learn more, visit healthwise.org
Find Care
Providers
Video Visit
Portal Login