Lassa Fever Case Report: Challenges in Making Early Diagnosis

Introduction: Lassa fever is a disease of public health importance because of the associated morbidity and high case fatality rate among hospitalized patients. Even after recovery, there may be residual problems such as sensorineural hearing loss. The initial presentation of Lassa fever may be with non-specific symptoms similar to what is seen in the more common febrile illnesses such as malaria or typhoid fever. In such a setting therefore, timely diagnosis of Lassa fever may be difficult. Case Report: We report a case of Lassa fever that presented to our institution. She was a middle aged woman who had non-specific symptoms of febrile illness and who died in less than 48 hours of admission. She had a subtle bleeding on the lip just before death which was what raised the suspicion for Lassa fever. Laboratory confirmation of Lassa fever was made retrospectively. Conclusion: When the presenting symptoms are non-specific, a high index of suspicion is required for timely recognition of Lassa fever. Early diagnosis is important for prompt therapeutic intervention as well as for limiting the spread of the disease. This is the second case of Lassa fever presenting to our hospital, but the first published case of Lassa fever from our hospital.

Advances in Infectious Diseases morbidity as well as high case fatality rate in hospitalized patients. Lassa fever is one of the viral haemorrhagic fevers and it is caused by Lassa virus which is an arenavirus transmitted by Mastomysnatalensis either directly by eating rat or by taking food contaminated by rat's urine or faeces [1] [2]. Lassa fever is endemic in Nigeria and in some other West African countries such as Guinea, Benin, Mali, Ghana and Sierra Leone and Senegal [1] [2]. Lassa fever is also found outside West Africa in countries such as Central African Republic and Democratic Republic of the Congo [1]. Also, there have been reports of imported Lassa fever to other continents of the world [3] [4] [5].
A number of complications can occur in Lassa fever, of which one of the disabling complications is sensorineural hearing loss. In a study done in Sierra Leone [1], a high incidence of sensorineural hearing loss was found among those suffering from Lassa fever. Sensorineural hearing loss was also found among those with serological evidence of past exposure to Lassa virus [1], indicating that hearing loss may persist in some people even after recovery from Lassa fever. Although, majority of subjects (about 80%) with Lassa fever may have mild or no symptoms [8], in hospitalized patients, the case fatality rate may be as high as 28% [9].
The importance of timely diagnosis of Lassa fever is that both the morbidity and mortality associated with Lassa fever can be reduced and also secondary infection from the patient can be prevented. Starting ribavirin early (within the first six days) in addition to supportive care improves clinical outcome in Lassa fever [1].
Up till December 31st, 2019, no confirmed Lassa fever case had been reported from the Enugu State University of Science and Technology Teaching Hospital, Parklane, Enugu, Nigeria. Between January 2020 and February 2020, the first two cases of Lassa fever presented within a space of five weeks of each other to this hospital. The two patients died. However, no health worker was infected even though the diagnosis of Lassa fever was not made early enough. The second of the two cases is presented in this case report in order to highlight the challenges in making timely diagnosis of Lassa fever.

Case Report
On the 18th of February, 2020, a 56 year old female Nigerian who was residing in a suburb near the state capital of Enugu State was referred to our institution when her health condition did not improve following initial treatment. She gave a history of fever and generalized body weakness of a week duration, and difficulty in breathing and abdominal pains of three days duration. The fever was of high grade, intermittent, worse at night and associated with chills and rigors.
There was no history of vomiting, diarrhea or bleeding from any part of the

Discussion
We reported a case of a middle aged woman who presented with non-specific symptoms of febrile illness in a center where malaria and typhoid fever are more common and Lassa fever is rare. She died in less than 48 hours of admission. March, 2020. The patient in this case report had never travelled out of Nigeria.
She had had no contact with anybody from outside the country, at least, in recent times. She was a farmer living in a suburb. Therefore, the possibility of COVID-19 as a differential diagnosis was very unlikely. Multidrug resistance by malaria parasites is a problem in this part of the world. Plasmodium falciparum is the commonest malaria parasite in African countries, including Nigeria [11] and it is one of the two species of malaria parasites notorious for multidrug resistance [12]. Therefore, even if non-specific symptoms persist in a patient after malarial therapy in this part of the world, it still may not rule out the possibility of the person having malaria.
Although, the patient had fever in the early stage of her illness, fever was not prominent when she presented to our hospital and she was not febrile on examination. Bleeding which is considered to be the hallmark of Lassa fever and of other viral haemorrhagic fevers was subtle and a terminal event in this patient. A little bleeding was noticed around her lip just before death which was what raised the suspicion for Lassa fever. In one case-control study in Sierra Leone, mucosal bleeding occurred only in 17% of cases of Lassa fever patients [13]. Un- Woyessa et al. [16] reported two cases of Lassa fever in Liberia which were misdiagnosed by the primary health physician as malaria and respiratory tract disease. The two patients died before laboratory tests confirmed them as cases of

Conclusion and Recommendation
This is the second case of Lassa fever presenting to our hospital, but the first published case of Lassa fever from our hospital. In the part of the world where malaria and other febrile illnesses are common and Lassa fever is rare, a very high index of suspicion is required to be able to recognize a case of Lassa fever early enough. Late presentation of Lassa fever patients to centers capable of managing cases of Lassa fever still remains a major challenge. Timely diagnosis of Lassa fever is important for timely institution of definitive therapy as well as for the containment of the disease.