Lassa fever caused by Lassa virus (LASV) is a deadly hemorrhagic fever that was neglected in recent decades following its discovery and characterization [1,2,3]. It is endemic in many parts of West Africa, predominantly in Ghana, Benin, Côte d’Ivoire, Mali, Sierra Leone, Guinea, Liberia, and Nigeria [2,3,4,5]. The disease is transmitted to humans by the primary reservoir host of the multimammate rodent called Mastomys nataliensis, which lives in association with humans in the greater part of Sub-Saharan Africa, including Cameroon [2, 5, 6]. Other primary reservoir hosts include Mastomys erythroleucus, Hylomyscus pamfi, Rattus rattus, and Mus musculus [5]. As such, most human infections with LASV result from rodent-to-human transmission, as well as human-to-human infection [4, 7]. There are an estimated 300,000–500,000 cases of Lassa fever each year [1, 5, 8, 9], with a case fatality rate of 15-33% for hospitalized patients and as high as 50% during an epidemic [4,5,6, 9, 10]. However, accurate estimates of the number of Lassa fever cases and deaths are not possible because of the limited availability of epidemiological data since most people infected with LASV have mild symptoms or are asymptomatic [4].

The application of strict quarantine strategies in endemic and nonendemic areas and the rapid diagnosis of the Lassa virus are needed for effective therapeutic intervention and prevention. However, current knowledge of Lassa cases is hindered by clinical diagnoses since the majority of infected patients are asymptomatic or present with flu-like and gastrointestinal symptoms such as fever, headache, malaise, abdominal pain, vomiting, body pains, and diarrhea, which are common to other febrile illnesses, such as malaria, typhoid fever, leptospirosis, and arbovirus diseases, which are common in West African hospitals [2, 7]. Thus, it is necessary to carry out a laboratory diagnosis of the disease. Laboratory diagnosis of LASV is a challenge due to the absence of proper infrastructure and equipment [2, 6, 7].

The definitive diagnosis of a Lassa virus infection to date depends on virus isolation or serological and molecular techniques [11]. Examples of molecular techniques include Reverse Transcription -Polymerase Chain Reaction (RT‒PCR), and quantitative PCR. Nevertheless, the lack of infrastructure, equipment and funds in some developing countries in Africa makes it almost impossible to use [2, 11]. Considering that most Lassa-infected patients develop specific immunoglobulin M (IgM) and G (IgG) antibodies during the first days of illness, diagnostic immunoassays such as enzyme-linked immunosorbent assays (ELISAs), immunofluorescence assays (IFAs), and rapid diagnostic tests have been developed for the detection of antigens and antibodies with high sensitivity (> 88%) and specificity (90%) [2, 4, 11]. As such, laboratory diagnosis in West Africa relies on the detection of LASV antigen (Ag) via immunoassays. The porosity of the borders of Nigeria–Cameroon [12]and increased movement across countries in West Africa put Cameroon at risk of this important zoonotic pathogen. The possible migration of animals borderlessly remains a big risk factor in disease transmission. Interestingly, there have been no reports of Lassa fever diseases in Cameroon.

Recently, an outbreak of Lassa fever in Ghana, another country in West Africa [13], was a clear indication of a possible Lassa outbreak. As such, with the possibility of recurrent Lassa infection, there is a need for a robust surveillance system to quickly detect and respond to cases and a need to expand clinical research capacity since early identification of infected individuals is important for the prompt implementation of appropriate preventive barriers.

There is a dearth of data on the prevalence of Lassa virus disease in Africa, with no reports of LASV cases in Cameroon as a whole. Thus, it is important to evaluate the exposure of this virus among the immunocompromised population for proper clinical management and surveillance for adequate management during disease epidemiology.

Cameroon is one of the countries with a high prevalence of human immunodeficiency virus (HIV) in the West and Central African Sub Region [14]. The prevalence of HIV in this country stands at 2.9% [15]. HIV decreases the white blood cells of the human body, thereby weakening the immune system and making them susceptible to opportunistic infections [16]. Since the onset of HIV morbidity and mortality rates among people living with HIV have been increasing [17]. While cases of LASV continue to spread in West Africa, the effort to control the spread, especially in immunocompromised patients like HIV patients is vital for healthcare management. Cases of Lassa fever co-infection with HIV have been reported in Nigeria [17, 18]. However, reported cases of coinfection of Lassa virus and HIV are lacking in Bamenda which trans-boarded Nigeria with an outbreak of LASV [6]. Considering that HIV suppresses cellular immunity and elevates inflammatory conditions that can lead to aggravated symptoms in persons with co-infections it is necessary to investigate the prevalence of LASV among HIV patients [19]. Thus, it is important to evaluate the exposure of this virus among the immunocompromised population for proper clinical management and surveillance for adequate management during disease epidemiology.

This study therefore sought to evaluate the seroprevalence of Lassa virus antibodies among HIV patients in the northwestern region of Cameroon. The data obtained from this study address the knowledge gap with a renewed commitment to prevent and control Lassa fever.