Newswise — Chapel Hill, North Carolina– A new study led by researchers at the Institute for Global Health and Infectious Diseases at the University of North Carolina School of Medicine in Chapel Hill shows that improvements in the detection and treatment of Lassa fever are urgently needed. lancet infection.

Lassa fever is a severe Ebola-like disease that has been designated by the World Health Organization as one of the world’s greatest pandemic threats and causes thousands of deaths each year, primarily in Nigeria, Liberia and Sierra Leone. The virus is primarily transmitted by rodents, but it can also be passed from person to person through direct contact with the blood, body fluids, or secretions of an infected person. Outside of West Africa, more than 32 imported cases have been reported around the world, including the United States, of which one-third have been fatal, underscoring its international importance.

“Lassa fever remains a major public health threat in West Africa, with high infection and mortality rates, often exceeding 20% ​​in some settings,” he said. William A. Fisher Director of Emerging Pathogens at the Institute, who led the PREPARE study with Dr. II. david wall. The two are co-directors of the UNC Project-Liberia.

“Many of these deaths can be prevented by increasing access to early diagnosis and supportive care, and in some cases initiating effective treatments. Additionally, with more than 30 imported cases of Lassa fever reported in non-endemic countries, one-third of which are fatal, the importance of early detection and treatment extends beyond West Africa,” said Dr. Fisher, associate professor of pulmonary and critical care medicine.

Testing is currently limited, even in countries where Lassa fever is endemic, and many cases go undiagnosed. The UNC-Liberia team, in collaboration with the hospital and Liberia’s National Institute of Public Health, installed a real-time PCR test for Lassa virus at Phebe Hospital in rural Liberia as the centerpiece of UNC’s on-site research efforts.

However, as Dr. Wall points out, a lack of diagnostic testing is only part of the reason why Lassa fever is underdiagnosed.

“Before ordering a test, you must have a clinical suspicion that Lassa fever may be causing the patient’s illness. Although we have known about Lassa fever for decades, we do not fully understand the spectrum of symptoms of this infection.”

research design

The Prevalence, Etiology, and Persistence (PREPARE) study was conducted from July 2018 to August 2024 at two hospitals in central Liberia: Phoebe Hospital and CB Dunbar Hospital. Researchers at UNC and Phoebe Hospital enrolled 435 patients aged 5 years and older who were hospitalized with febrile illness or clinical suspicion of Lassa fever.

All participants in this study underwent plasma LASV RNA RT-PCR testing, and participants with confirmed infection were followed during hospitalization and for up to 1 year after discharge to assess viral dynamics, immune responses, and clinical outcomes.

Research results

• The prevalence of Lassa fever was high in hospitalizations for fever, with 11% of febrile patients having Lassa fever, even though it was not clinically suspected.
• Mortality was related to viral load and immune response, with patients who died having higher viral loads and weaker antibody responses.
• Children are particularly affected, with 43% of confirmed cases being between the ages of 5 and 17.
• Diagnostic gaps still exist. Limited access to PCR testing and overlap in symptoms with other common infections contribute to underdiagnosis.

“These findings highlight how easily patients can bypass routine clinical screening,” said Dr. Wall, professor of medicine. “Our data make clear that unless we expand our diagnostic breadth beyond what is expected of routine diagnosis, a significant number of Lassa virus infections will be missed.”

Missed cases not only worsen patient outcomes, but also expose healthcare workers to infection and increase the risk of person-to-person transmission in clinical settings. Long-term data showing that severe Lassa fever is correlated with increased viral load, organ damage, and worse outcome emphasizes the importance of early detection and antiviral treatment. Complications usually appear during the second week of illness, so the window for effective intervention is narrow.

“Early detection of Lassa fever can help those infected and prevent this dangerous pathogen from becoming a threat to those near and far,” added Dr. Fisher.

An editorial review of the study was also published. lancet infectionhighlights the impact of missed diagnoses, recognizing the need to scale up point-of-care diagnostics, vaccines, and treatments to reduce mortality, prevent epidemics, and ultimately work towards eradicating Lassa fever in Liberia and other endemic areas. Early detection and effective treatment are essential to save lives.

The PREPARE study was funded by the National Institute of Allergy and Infectious Diseases and the National Institutes of Health.

UNC Institute for Global Health and Infectious Diseases

UNC founded in 2007 Institute for Global Health and Infectious Diseases Research at UNC School of Medicine began more than 30 years ago with infectious disease physician researchers studying HIV in China and Malawi. Over the years, our work has expanded to include emerging pathogens, cancer, women’s health and vector-borne diseases such as malaria, and we have shaped policy through evidence-based research around the world. Through research, training, and service, UNC-Chapel Hill develops emerging scientists who advance patient care and practice, addressing the most important global health issues of our time while promoting research excellence.