Lassa virus, the pathogen that causes Lassa fever, remains a major public health threat in West Africa, demanding critical attention and rigorous research efforts, particularly to develop an effective vaccine. In this first LEAP4WA student blog post, Tiangay delves into the compelling reasons why research on Lassa fever should be prioritized and the role that early career researchers can play in this effort.
Lassa fever is endemic in West Africa, particularly in Nigeria, Liberia, Guinea, and Sierra Leone, where I live and work. Despite being identified over 50 years ago, Lassa fever continues to pose a substantial public health threat causing about 300,000 people to fall sick and over 5000 people to die each year. While progress is being made in developing medical countermeasures to tackle Lassa fever, there remain significant challenges in the diagnosis and treatment of Lassa fever. Current clinical diagnostic approaches rely on serology assays (i.e., testing samples of bodily fluids), including ELISA, which have sensitivity and specificity issues due to the genetic diversity of Lassa virus, the pathogen that causes Lassa fever. No Lassa fever-specific therapeutic is currently available. Ribavirin is at present the drug of choice; however, its effectiveness is highly dependent on how early it is administered, and it is known to result in toxicity in some patients. Most concerningly, there is still no licensed vaccine to prevent Lassa fever. Moreover, in this era of heightened global connectivity, international travel, and the climate crisis, Lassa virus poses a growing epidemic threat as it risks being exported or expanding to non-endemic areas. There is a critical need for more research to better understand the pathogenesis, genetic diversity, and host interactions of Lassa virus and to urgently develop an effective vaccine and cost-effective antiviral treatments.
In Kenema District of Sierra Leone where Lassa fever is endemic, most people are aware of Lassa fever and that it is spread by its natural vector, the Natal multimammate mouse. However, because the early clinical symptoms of Lassa fever (including fever, weakness, body pains, and vomiting) are similar to other endemic disease such as malaria, Lassa fever diagnosis is often delayed, which can lead to fatal outcomes by the time an individual suffering from Lassa fever is diagnosed. In individuals who survive severe Lassa fever infection, side effects can be debilitating, including loss of hearing.
I work at the Kenema Government Hospital (KGH), Viral Hemorrhagic Fever (VHF) laboratory in Sierra Leone. I’m also an MSc candidate at the London School of Hygiene and Tropical Medicine and one of the LEAP4WA scholars. As an emerging Laboratory scientist, I am involved in routine laboratory diagnosis, viral genomic sequencing, and research activities on Lassa virus (LASV). I routinely perform a range of diagnostic assays, including Lassa virus-specific RDT and ELISA, to detect LASV-specific proteins and antibodies against the virus in samples collected from patients reporting to the hospital with symptoms that meet the case definition of Lassa fever. I also perform molecular assays, including RT-PCR, to detect LASV genetic material from suspected samples and monitor viral load in patients admitted to the hospital with Lassa fever. KGH is the national reference laboratory for VHF viruses in Sierra Leone and a reference laboratory in the Mano River Union basin, which includes Liberia. We receive suspected samples from all over Sierra Leone, and sometimes from Liberia, to test for Lassa virus infection.
My work on LASV at KGH helps impact lives and public health decisions in Sierra Leone through the rapid detection of the virus, including by authoring LASV genomic sequences from clinical isolates in Sierra Leone, which are available in GenBank (PRJNA962938). These sequences will further enhance our understanding of LASV epidemiology and will be vital for diagnostics development. In addition to diagnosis, KGH also plays a significant role in ensuring people affected by Lassa fever receive the best care available to recover from the disease and to conduct the necessary surveillance to track the source of infection in the environment.
The work on Lassa fever at KGH has provided substantial knowledge on the burden of disease, clinical characteristics, and genetic diversity of Lassa virus that continue to inform the development of Lassa fever vaccines and diagnostics to detect, diagnose, and prevent Lassa fever. Various research groups from around the world are working together to develop vaccines that can stimulate an effective immune response to prevent Lassa fever. LEAP4WA is one such group that is developing a cutting-edge vaccine candidate to prevent Lassa fever in West Africa, working at a range of sites across the region. I’m proud to be part of this effort to develop an innovative vaccine to one day prevent Lassa fever. It is critically important to support early career researchers like myself to strengthen the capacity of future scientific leaders in the region. We are eager to dive into the science of emerging infectious diseases and passionate about contributing to the development of locally-led and innovative public health solutions.
It is also vital that we advocate for the prioritization of research on Lassa fever due to its impact on public health in West Africa and the serious threat it poses for global health more broadly. Lassa fever is a deadly disease that affects hundreds of thousands of people each year. All of us engaged in the fight against Lassa fever, whether scientists, healthcare workers, or policymakers, can learn from the experiences of people who have been affected by this disease, including healthcare workers who are at the forefront of the growing Lassa fever epidemic. It is crucial that all stakeholders, including community members and healthcare workers, are active contributors to this research. A collaborative effort from the global health community, as seen through LEAP4WA, is crucial to address the multifaceted challenges posed by Lassa fever, and to ultimately safeguard vulnerable populations and foster a world resilient to the threats of infectious diseases.