Introduction And Epidemiology
Lassa Fever (also known as Lassa Hemorrhagic fever – LHF) is a type of viral hemorrhagic fever caused by Lassa virus belonging the arenaviruses family of enveloped RNA-viruses.
The virus is transmitted by ingestion of food contaminated by the urine and faeces of the multimammate rat (Mastomys natalensis).
The disease was discovered in 1969 in Lassa, Borno state, Nigeria from where the illness got its name. It is now endemic in many parts of West Africa including Nigeria, Liberia, Sierra Leone and Guinea.
Since the incident in 1969, Lassa fever has become a major health challenge in West Africa with Nigeria bearing the highest burden.
An estimated 100,000 to 300,000 cases are recorded annually with approximately 5,000 deaths so far.
Statistical data shows that outbreaks are commoner in the dry season of the tropical African climate spanning from November through to May.
Signs And Symptoms
Symptoms begin to appear 1-3 weeks after a patient is exposed to the infected Mastomys rat and they may be mild with the following symptoms;
- Slight fever
- General malaise and weakness
- Headache
In 20% of people infected with the Lassa fever virus, the disease may progress to more severe symptoms.
- Haemorrhaging (in gums, eyes, or nose, etc)
- Respiratory distress
- Repeated vomiting
- Facial swelling
- Pain in the chest, back, and abdomen
- Shock
Neurological problems have also been described, including hearing loss, tremors, and encephalitis. Death may occur within two weeks after symptom onset due to multi-organ failure.
Risk Factors For Infection In Nigeria
Inhalation or ingestion of food contaminated with the urine or faeces of an infected multimammate rat is the single most common and prevalent route of transmission, thus making the disease essentially a zoonitic animal.
However, human contact with other infected humans or objects that have been contaminated can be a very disastrous means of transferring the infection, especially within the health care setting.
This has warranted the need to ensure a very high index of suspicion amongst the health workers within the hospital or health institution.
It has become a common practice for farmers to dry their produce especially cassava flour (Garri) in the open sunlight. In areas where the multimammate rats abound, these farm produce can become contaminated and pose a health risk to consumers of the products and the farmers themselves.
Hence, in the midst of all of these, measures are being put in place to ensure good hygiene and proper processing of agricultural products to prevent their contamination.
Also, the high index of suspicion, prompt management and use of personal protective equipment(PPE), and regular handwashing are highly recommended and emphasized by the health sector.
There is also a place for containment and quarantine of suspected cases and exposed contacts, but yet, there was an anomalous and erroneous approach by the health team in a notable Nigerian health care centre that needs to be immediately repealed and worked upon.
Diagnosis
The disease is confirmed by a procedure known as ELISA (Enzyme-linked Immunosorbent Assay). Other diagnostic methods include Immunohistochemistry (post-mortem), Reverse Transcriptase Polymerase Chain Reaction(RT-PCR), and viral culture.
Treatment And Management
Prevention remains the best means of curtailing the infection and this is carried out by proper environmental hygiene, proper storage of food and proper cooking of food before eating.
Ribavirin, an antiviral agent has however found use in the treatment of Lassa fever especially in the early stages of the disease. Supportive management including fluid and electrolyte support, oxygenation and blood pressure monitoring are also major parts of the management.
The Wrong Approach Adopted In A Nigerian Health Institution
Recently, the outbreak has formed a surge as is expected in this dry season. The first 7 weeks of the year 2020 has experienced up to 586 cases and 103 deaths with a 17.6% fatality ratio in Nigeria.
Only the 7th week of the year (3rd week of February) recorded 115 confirmed cases and 18 deaths nationwide.
The number of new cases is rising expectedly and the health team is supposed to be aware of this and put some more drastic measure in place, especially at this time of the year. What are some of the dangerously wrong approaches adopted by the Nigerian health institutions with Index Institution(name not specified) as a case study?
1. Ignoring High Index Of Suspicion
There should be a high index of suspicion once any suggestive symptom or complaint is noticed. This will ensure that more care is taken in handling such patients and the appropriate management instituted accordingly.
In the index Nigerian health institution, a case was totally missed with the resultant death of the patient and possible contamination of the operating theatre and the enlistment of some health workers as suspected cases. This could have been prevented if there was a high index of suspicion and the appropriate PPE used.
2. Non-enforcement of Personal Protective Equipment Use
Whether the problem is the unavailability of these protective equipment or that their use is not enforced is a question I cannot find answers to at this time, but what should be done must be done.
For special diseases like Lassa hemorrhagic fever and other hemorrhagic fevers, the PPE to be implemented would be significantly different and more sophisticated than the regular hand gloves and ward coats.
Waterproof aprons and total body gowns can be used for suspected cases to minimize contact to the barest minimum and hence, minimize the risk of transmission to health workers and other patients. Quarantine is also very important and would be discussed in the next session.
3. Inadequate Quarantine and Isolation
The index Nigerian institution was reported to quarantine newly suspected health worker cases by sending them home from the hospital. But this is largely insufficient to curtail spread should in case one or more of the suspected cases come down with the disease.
The normal quarantine period for the disease should exceed the incubation period of the disease(1-3 weeks) during which suspects and contacts are to be isolated and declared free before been released.
It looks like a general problem of not being able to adequately handle quarantine in Nigeria and I am yet to fully understand the reasons why that remains a difficult thing yet.
Commendable Actions So Far
In spite of all the shortcomings, the cases management in Nigeria has witnessed come commendable efforts. The establishment of specialised centres in the management of Lassa fever is worth noting.
The index hospital promptly disinfected the rooms that the Lassa fever patient possibly had direct or indirect contact with.
But another thing that needs to be worked upon would involve the area of research which is largely undermined in Nigeria for several reasons, though not all justifiable.
A note of the prevention in the communities, as well as in the hospital is important in the reduction of the number of new cases of Lassa fever in this dry season in West African countries. But more importantly, is the need to remind the health sector of the extra measure that must be put in place to ensure total or drastic reduction at most, of new cases of Lassa Hemorrhagic Fever.
References
Centre for Disease Control(CDC)
Nigeria Centre for Disease Control(NCDC), Weekly Journal, Week 07: 10 -16 February 2020 – Lassa Fever Situation Report
