Recognising Early Signs Of Lassa Fever

Lassa fever is a viral illness spread by the common African rat. It is an animal-borne disease that can cause serious health problems in humans if not treated and monitored at an early stage. This article will give you all the information you need about Lassa fever, its causes and treatments, and, crucially, its early signs and symptoms.

What is lassa fever?

Lassa fever is a highly contagious and potentially fatal animal-borne disease that can be transmitted from rodents to humans. It is mainly endemic to West African countries such as Guinea, Liberia, Nigeria, and Sierra Leone, but a few cases have been reported in other African countries. The disease is caused by the Lassa fever virus (LSAV) and, in severe cases, can cause hemorrhagic fever and systemic illness.

Since its discovery in Nigeria in 1969, Lassa fever outbreaks have continually occurred in West Africa, posing a significant public health challenge. The World Health Organization (WHO) has included Lassa fever on its list of priority pathogens and has highlighted the need for scientific and social developments to address it. Even more concerningly, travel-associated Lassa fever cases have been reported in several countries outside West Africa in recent years, including the United States, Canada, the United Kingdom, the Netherlands, Israel, Sweden, and Germany, raising concerns about the global spread of the disease.¹ 

Transmission

It is important to understand how this disease is transmitted. 

The host for the Lassa virus is the "multimammate rat" (Mastomys natalensis), which is widespread in West Africa. This rodent excretes the virus in its urine, posing a severe and immediate risk to human health. The virus is primarily transmitted through ingestion or inhalation, as well as direct contact with contaminated materials or exposure to open wounds.

Given that Mastomys rodents are highly adaptable and frequently inhabit homes and areas where food is stored, the risk of direct contact transmission is significantly high. Furthermore, the virus can be transmitted by inhaling any tiny airborne particles contaminated with infected rodent excretions, which can occur whilst sweeping or dusting.

It is crucial to note that the transmission of the Lassa virus can also occur through person-to-person contact, particularly in healthcare settings where proper personal protective equipment (PPE) is not used. The virus can be spread through exposure to infected bodily fluids, tissues, secretions, or excretions, and contaminated medical equipment, such as reused needles.

Proper hygiene practices, minimising exposure to contaminated materials, and using appropriate personal protective equipment (PPE) in healthcare settings are all essential in preventing the spread of the Lassa virus. However, it is also important to raise awareness and educate the public about how to prevent Lassa fever from spreading, especially in areas where the virus is prevalent, to help prevent further outbreaks.²

Early signs and symptoms of lassa fever

It is important to be aware that signs and symptoms of Lassa fever may not appear right away. Typically, they show up 1-3 weeks after a person comes into contact with the virus. In around 80% of cases, the symptoms are mild - which allows Lassa fever to go undetected and undiagnosed in the community. Mild symptoms include:

• Fever
• Cough
• Tiredness
• Sore throat
• Headache 

It is important to seek medical attention if you suspect you may have been exposed to the virus and are experiencing any of these symptoms. If the infected individual is not treated at an early stage, the disease may progress to more serious symptoms including:^1,3

• Difficulty breathing
• Neck, chest, or stomach pain
• Severe vomiting or diarrhoea
• Facial swelling
• Bleeding from your eyes, nose, mouth, or other mucous membranes
• Seizures
• Confusion

Complications

Various complications can be seen in people with Lassa fever. It is reported that 1 in 3 people with Lassa fever has partial or complete hearing loss, even in mild cases. This may be temporary or permanent.

Patients with severe Lassa fever can have life-threatening complications such as:³

• Loss of the foetus happens in over 75% of pregnancies when the pregnant parent is infected with the Lassa virus
• Inflammation and infection of organs, such as the liver (hepatitis)
• Uncontrolled bleeding 
• Sudden kidney failure (acute kidney injury)
• Inflammation of the lining around the heart (pericarditis)
• Issues with brain function (encephalopathy)
• Formation of fluid around the lungs (pleural effusion)
• Low oxygen saturation (Acute respiratory distress syndrome (ARDS))
• Blood clotting disorders (disseminated intravascular coagulation/DIC)
• Sepsis which is a severe reaction to infection

Death can occur within 14 days of onset in fatal cases. Lassa fever can be particularly severe during the late stages of pregnancy, with a high risk of maternal death and foetal loss. Studies have shown that more than 80% of cases during the third-trimester result in such outcomes. It is important for pregnant people to take extra precautions to avoid infection and seek immediate medical attention if they experience any symptoms.⁴

Diagnosis

Lassa fever can be difficult to diagnose as its symptoms are not specific and can mimic other viral haemorrhagic fevers, such as Ebola, as well as other diseases that cause fever, like malaria, typhoid fever, and yellow fever. To make matters more difficult, laboratory specimens used for diagnosis can be hazardous and require extreme care during handling. Lassa virus infections can only be diagnosed in the laboratory using the following tests:³

• Blood tests
• Throat swab
• Urinalysis
• Lumbar puncture (spinal tap)

Treatment

Healthcare providers often treat Lassa fever with an antiviral medication called ribavirin, which has been proven to be effective in treating Lassa fever. Studies show that ribavirin is most effective when administered early in the course of the illness. In severe cases of Lassa fever, ribavirin may be combined with other treatments, such as intravenous fluids, electrolytes, and blood products.⁵ The patient might be given other treatments depending on their condition, such as:³

• Dialysis treatment, if the patient is diagnosed with kidney damage
• If the patient is facing breathing difficulties, supplemental oxygen needs to be provided to help them breathe
• Administration of IV fluids, medications, or supplements to correct electrolyte imbalances

Summary

Lassa fever is a viral disease that can be fatal if not treated promptly and properly. It is essential to be aware of its causes, transmission, early signs, and symptoms to prevent the spread of the virus and seek medical attention right away. Symptoms of mild Lassa fever include fever, tiredness, cough, sore throat, and headache, but the disease can progress to severe symptoms and complications such as chest, neck, or stomach pain, difficulty breathing, and even death. Preventive measures such as avoiding contact with rodents and keeping living spaces clean are essential, and early diagnosis and treatment with the antiviral medication ribavirin are crucial. If you suspect that you may have been exposed to the virus, seek medical attention immediately, especially if you're pregnant.

FAQ’s

Can lassa fever be prevented?

You can reduce your risk of Lassa fever by keeping your living space free of rodents and protecting yourself when you’re around infected people. Other things you can do to reduce your risk of infection are:

• Avoid contact with rodents, especially in areas where Lassa fever is reported. Living spaces should be kept clean always and food should be kept in closed containers so that it does not attract rodents and other pests.
•  Protective coverings should be worn while caring for someone who has or might have Lassa fever. This includes gloves, masks, gowns, goggles and boots.
• If you’re infected with the Lassa virus, you should isolate yourself from others to prevent spreading it.
• Always ensure to take guidance from a healthcare provider regarding the precautions you need to take while treating a patient or if you are a patient yourself.

What can I expect if I have lassa fever?

If you have Lassa fever, it is important to know that healthcare providers and your caretakers will have to take special precautions to protect themselves and others. This includes wearing protective gear and clothing like gloves, masks, goggles, and aprons. They will also isolate you from other people to prevent the spread of the virus.

If you're pregnant and have Lassa fever, you will need to be treated with antiviral medications as soon as possible. Healthcare providers will closely monitor you and your baby's health. It is important to talk to your provider about what to expect and what the best treatment options are for you and your baby's health.

Most cases of Lassa fever are mild and can take a week or longer to recover from. However, if you experience hearing loss, it's important to note that about half of people with this symptom regain their hearing within a few weeks.

When should I see my healthcare provider?

You should seek medical attention immediately if you're experiencing any of the symptoms of Lassa fever mentioned above and you have recently travelled to countries in West Africa. Additionally, if you're pregnant or think you might be pregnant, it is crucial to have a healthcare provider treat and monitor you carefully.

What is the survival rate of lassa fever?

The death rate for Lassa fever is around 1%. During outbreaks, the death rate can be much higher, especially for individuals who require hospitalisation.

For those who need to be hospitalised, the mortality rate for Lassa fever is around 15%. This means that around 15 out of every 100 people who require hospitalisation for Lassa fever will die from the virus.

For pregnant individuals, the mortality rate is even higher, at around 33% or 1 in 3 people. This highlights the importance of seeking medical attention early if you're pregnant and experiencing symptoms of Lassa fever.³