A motorcyclist drives past a street sign for the Institute of Lassa Fever Research and Control in Irrua Specialist Teaching Hospital in Irrua, Edo State, midwest Nigeria, on March 6, 2018Share on Pinterest
A motorcyclist drives past a street sign for the Institute of Lassa Fever Research and Control in Irrua Specialist Teaching Hospital in Irrua, Edo State, midwest Nigeria, on March 6, 2018. PIUS UTOMI EKPEI/AFP via Getty Images
  • A recent article in the Journal of Medical Virology discusses the dual impact of Lassa fever and COVID-19 in Africa.
  • The authors say that the emergence of COVID-19 has directed resources away from other infectious diseases, including Lassa fever.
  • To contain the disease, they recommend a mix of public hygiene information, enhanced research, and the development of treatments and vaccines.

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Lassa fever is an infectious disease transmitted from rodents to humans. Approximately 2 million people get Lassa fever each year, resulting in 5,000–10,000 deaths. The disease is endemic in West African countries, such as Guinea, Liberia, Nigeria, and Sierra Leone.

One of the major challenges when diagnosing the disease is the similarity of its symptoms, including sore throat, joint pains, and weakness, with many other diseases, such as dengue and typhoid fever.

Because of this, the condition is commonly under- and misdiagnosed.

The emergence of COVID-19 has further aggravated the identification and treatment of the condition due to the extra burden placed on public health systems around the world.

Earlier this year, an international team of researchers published an article highlighting the situation of Lassa fever in Africa following COVID-19, alongside public health strategies to contain it.

“Lassa fever is endemic to West Africa, “ Matt Price, Ph.D., told Medical News Today. Dr. Price is director of epidemiology at the International AIDS Vaccine Initiative (IAVI) and assistant clinical professor of epidemiology and biostatistics at the University of California San Francisco (UCSF). He was not involved in the article.

“However, reporting on the disease in the past has not been systematic, and our understanding of the epidemiology is incomplete. In recent years, Nigeria has been the epicenter for annual outbreaks of the disease, with case numbers peaking in 2020,” he added.

“Active disease surveillance is ongoing in Nigeria, and large, population-based epidemiology studies are underway in Sierra Leone, Guinea, Liberia, and Benin. This work will help us get a better understanding of the epidemiology of Lassa fever, “ he explained.

The article appears in the Journal of Medical Virology.

Currently, early diagnosis of Lassa fever is key for effective treatment. Doctors recommend Ribavirin, an antiviral medication, within the first 6 days of contracting the virus. If left untreated, the disease can lead to:

  • swollen airways
  • abdominal pains
  • diarrhea
  • vomiting
  • respiratory symptoms
  • loss of hearing
  • acute hemorrhagic fever
  • multiple organ failure
  • death

After the declaration that COVID-19 was a pandemic, medical resources were directed towards COVID-19, leading to compromised care for infectious diseases with higher fatality ratios, such as Lassa fever.

“Amid epidemiological Week 9 of 2020, when the first affirmed case of COVID‐19 was recorded in Nigeria, there was an increase in the number of affirmed [Lassa fever] cases,” write the researchers.

“Indeed, with steady care and treatment with ribavirin, case fatalities were still as high as 24%–33% in tertiary clinic settings […] whereas almost 13.5% of survivors [had] sensorineural hearing loss. Also, [Lassa fever] accounts for almost 22% of hospital maternal mortality in endemic ranges,” they add.

When asked how COVID-19 has impacted the management of Lassa fever in Africa,Dr. Price said:

“Lassa fever is of concern due to the severity of symptoms, risk of death, and concern over the potential of the virus as a bioweapon. In the wake of the Ebola crisis of 2014–2016, the international community has allocated funds to develop a safe and effective vaccine against Lassa fever.”

“As part of the efforts to prepare for Lassa fever vaccine clinical trials, large-scale, population-based epidemiology studies were planned in endemic regions to help guide clinical trial site selection — to ensure that the vaccines were tested where they were needed most,” he told MNT.

“Unfortunately, these studies were just getting underway as the COVID-19 pandemic was beginning.”

“With the shutdowns and service interruptions caused by COVID-19,” Dr. Price continued, “comes the potential for incomplete or erratic reporting of cases of Lassa fever, or interruptions of care and service for those reporting to healthcare centers with symptoms of Lassa fever.”

“Although we understand that infection with SARS-CoV-2 can be complicated by pre-existing conditions, such as obesity and diabetes, we do not know how this virus interacts with Lassa fever.”

– Dr. Price

When asked how similar Lassa fever is to COVID-19, Robert F. Garry, Jr., Ph.D., professor of microbiology and immunology at Tulane Medical School in New Orlean, LA, told MNT:

“Both are animal viruses that spill over to humans, RNA viruses with envelopes (spikes), [have a] large respiratory component/aerosol transmission, and cause economic and social disruption.”

This, however, may be where the similarities finish. Dr. Price added: “They are very different viruses. Lassa fever is an acute viral hemorrhagic fever caused by a single-stranded RNA virus known as Lassa virus — a member of the Arenaviridae family.”

“Infection occurs through ingestion or inhalation,” explained Dr. Price. “Casual contact, for example, skin-to-skin, does not spread the virus. It’s transmitted primarily through contact with the urine and feces of Mastomys rodents (the multimammate rat).”

“Some transmission may occur through bodily fluids, but this is not the primary mode of transmission and not thought to account for many cases.”

“SARS-CoV-2 is a respiratory virus, one of a few coronaviruses that infect humans. It’s highly infectious and easily transmitted from person to person via aerosolized droplets. Coronaviruses, including SARS-CoV-2, are also RNA viruses; however, they are a different family of viruses from Lassa fever, and their genetic makeup is very different,” he explained.

The article’s authors say that preventing Lassa fever can “only be achieved [by] educating people living in endemic areas on ways to protect themselves.”

They stress the importance of good “community hygiene” through using rodent-proof containers inside households and forming dumps away from houses.

They add that healthcare professionals should ensure people with fever receive COVID-19 polymerase chain reaction (PCR) tests to confirm whether or not they have COVID-19 and that lab workers dealing with possibly infectious samples should be trained and work in suitably-equipped labs.

The authors further say that funding for COVID-19 healthcare should be used to create long-term health frameworks.

“National control and prevention strategies should be implemented by providing effective and affordable diagnostics and treatment for [Lassa fever] and COVID‐19, enhancing laboratory diagnostics, clinical management, environmental control, and research,” write the researchers.

“The involvement of the communities affected is highly recommended, and the development of an effective and affordable vaccine would be the key pillars for the absolute management of [Lassa fever], especially during the challenging times of the COVID‐19 pandemic. Hence, the need to create awareness on the vaccine availability and make it readily accessible, in addition to early diagnosis and treatment, is paramount in creating a [Lassa fever]-free society,” they add.

Dr. Garry agreed on prioritizing vaccines and drugs for Lassa fever. He explained, however, that equitable distribution is crucial.

Dr. Price also agreed with the prioritization of vaccines, “The most effective control measures will make use of a safe and effective vaccine against Lassa fever. Improved surveillance will also play a role, as it will be key to identify outbreaks quickly so that additional vaccinations and other control efforts can be quickly implemented,” he added.

“There are several vaccine candidates in development, including one that IAVI is developing. We have gotten excellent support from the international community, with funding from the [The European & Developing Countries Clinical Trials Partnership (EDCTP)], [The Coalition for Epidemic Preparedness Innovations (CEPI)], and Wellcome (the latter funding for observational epidemiology, separate from work on a vaccine for Lassa fever).”

Dr. Price also highlighted the importance of public hygiene information: “Finally, good old-fashioned information and public health will also play an important role. Helping communities understand what Lassa fever is, what are the signs and symptoms, and what to do when they see a case — and what can be done to help communities lower their risk of exposure (e.g., reducing exposure to the animal vector).”