Field evaluation of validity and feasibility of Pan-Lassa rapid diagnostic test for Lassa fever in Abakaliki, Nigeria: a prospective diagnostic accuracy study.

BACKGROUND: Lassa fever is a viral haemorrhagic fever with few options for diagnosis and treatment; it is also under-researched with knowledge gaps on its epidemiology. A point-of-care bedside test diagnosing Lassa fever, adhering to REASSURED criteria, is not currently available but is urgently needed in west African regions with high Lassa fever burden. We aimed to assess the validity and feasibility of a rapid diagnostic test (RDT) to confirm Lassa fever in people in Nigeria. METHODS: We estimated the diagnostic performance of the ReLASV Pan-Lassa RDT (Zalgen Labs, Frederick, MD, USA) as a research-use-only test, compared to RT-PCR as a reference standard, in 217 participants at a federal tertiary hospital in Abakaliki, Nigeria. We recruited participants between Feb 17, 2022, and April 17, 2023. The RDT was performed using capillary blood at the patient bedside and using plasma at the laboratory. The performance of the test, based on REASSURED criteria, was assessed for user friendliness, rapidity and robustness, sensitivity, and specificity. FINDINGS: Participants were aged between 0 and 85 years, with a median age of 33·0 years (IQR 22·0-44·3), and 24 participants were younger than 18 years. 107 (50%) participants were women and 109 (50%) were men; one participant had missing sex data. Although the specificity of the Pan-Lassa RDT was high (>90%), sensitivity at bedside using capillary blood was estimated as 4% (95% CI 1-14) at 15 min and 10% (3-22) at 25 min, far below the target of 90%. The laboratory-based RDT using plasma showed better sensitivity (46% [32-61] at 15 min and 50% [36-64] at 25 min) but did not reach the target sensitivity. Among the 52 PCR-positive participants with Lassa fever, positive RDT results were associated with lower cycle threshold values (glycoprotein precursor [GPC] gene mean 30·3 [SD 4·3], Large [L] gene mean 32·3 [3·7] vs GPC gene mean 24·5 [3·9], L gene mean 28·0 [3·6]). Personnel conducting the bedside test procedure reported being hindered by the inconvenient use of full personal protective equipment and long waiting procedures before a result could be read. INTERPRETATION: The Pan-Lassa RDT is not currently recommended as a diagnostic or screening tool for suspected Lassa fever cases. Marked improvement in sensitivity and user friendliness is needed for the RDT to be adopted clinically. There remains an urgent need for better Lassa fever diagnostics to promote safety of in-hospital care and better disease outcomes in low-resource settings. FUNDING: Médecins Sans Frontières.

Atypical Mpox in a Nigerian Tertiary Health Facility.

BACKGROUND: We describe diverse clinical characteristics and course of confirmed mpox cases managed in a Nigerian tertiary health facility. METHODS: Clinical and epidemiologic data were analyzed, highlighting the unusual presentations of polymerase chain reaction (PCR)-confirmed mpox cases observed during the 2022 outbreak. RESULTS: Out of 17 suspected cases, 13 (76.4%) were PCR confirmed for mpox. The mean ± SD age for the participants was 28.62 ± 10.29 years (range, 2-55), of which 9 (64.3%) were male. Of the 13 PCR-confirmed cases, 5 (38.5%) had varicella zoster virus coinfection, 2 (15.4%) had HIV coinfection, and 1 (7.7%) had diabetes mellitus comorbidity. All patients experienced rash, with 6 (46.2%) having significant genital lesions and 1 (7.7%) having a severe perianal lesion. A lack of prodromal symptoms was reported in 3 (23.1%), and a prolonged prodrome (>1 week) occurred in 5 (38.5%). Skin lesions were polymorphic in 6 (46.2%), and solitary skin lesions occurred in 3 (23.1%), which persisted for >120 days in 7.7%. CONCLUSIONS: Clinical recognition, diagnosis, and prevention remain a concern in resource-limited settings. Our findings highlight the need to further evaluate unusual skin lesions and to include mpox screening for genital skin lesions that are presumed to be sexually transmitted infections. Revision of clinical case definition and enhanced surveillance are key to early recognition and prevention of spread.

Presence of Burkholderia pseudomallei in Soil, Nigeria, 2019.

Melioidosis, caused by the soil-dwelling bacterium Burkholderia pseudomallei, is predicted to be endemic in Nigeria but is only occasionally reported. This report documents the systematic identification of the presence of B. pseudomallei and B. thailandensis in the soil across multiple states in Nigeria.

Humoral and cellular immune responses to Lassa fever virus in Lassa fever survivors and their exposed contacts in Southern Nigeria.

Elucidating the adaptive immune characteristics of natural protection to Lassa fever (LF) is vital in designing and selecting optimal vaccine candidates. With rejuvenated interest in LF and a call for accelerated research on the Lassa virus (LASV) vaccine, there is a need to define the correlates of natural protective immune responses to LF. Here, we describe cellular and antibody immune responses present in survivors of LF (N = 370) and their exposed contacts (N = 170) in a LASV endemic region in Nigeria. Interestingly, our data showed comparable T cell and binding antibody responses from both survivors and their contacts, while neutralizing antibody responses were primarily seen in the LF survivors and not their contacts. Neutralizing antibody responses were found to be cross-reactive against all five lineages of LASV with a strong bias to Lineage II, the prevalent strain in southern Nigeria. We demonstrated that both T cell and antibody responses were not detectable in peripheral blood after a decade in LF survivors. Notably LF survivors maintained high levels of detectable binding antibody response for six months while their contacts did not. Lastly, as potential vaccine targets, we identified the regions of the LASV Glycoprotein (GP) and Nucleoprotein (NP) that induced the broadest peptide-specific T cell responses. Taken together this data informs immunological readouts and potential benchmarks for clinical trials evaluating LASV vaccine candidates.

Early onset of neurological features differentiates two outbreaks of Lassa fever in Ebonyi state, Nigeria during 2017-2018.

Lassa fever (LF) is an acute viral haemorrhagic illness with various non-specific clinical manifestations. Neurological symptoms are rare at the early stage of the disease, but may be seen in late stages, in severely ill patients.The aim of this study was to describe the epidemiological evolution, socio-demographic profiles, clinical characteristics, and outcomes of patients seen during two Lassa fever outbreaks in Ebonyi State, between December 2017 and December 2018. Routinely collected clinical data from all patients admitted to the Virology Centre of the hospital during the period were analysed retrospectively. Out of a total of 83 cases, 70(84.3%) were RT-PCR confirmed while 13 (15.7%) were probable cases. Sixty-nine (83.1%) patients were seen in outbreak 1 of whom 53.6% were urban residents, while 19%, 15%, and 10% were farmers, students and health workers respectively. There were 14 (16.8%) patients, seen in second outbreak with 92.9% rural residents. There were differences in clinical symptoms, signs and laboratory findings between the two outbreaks. The case fatality rates were 29.9% in outbreak 1 and 85.7% for outbreak 2. Neurological features and abnormal laboratory test results were associated with higher mortality rate, seen in outbreak 2. This study revealed significant differences between the two outbreaks. Of particular concern was the higher case fatality during the outbreak 2 which may be from a more virulent strain of the Lassa virus. This has important public health implications and further molecular studies are needed to better define its characteristics.

Prevalence and outcome of Lassa fever among hospitalized patients in Ebonyi State, Nigeria, 2018-2019.

Lassa fever (LF) is a viral hemorrhagic illness endemic in West Africa. Annually, about 300,000-500,000 people are being infected, with about 5000 deaths. Symptoms of LF include high grade fever, headache, malaise, abdominal pain, vomiting, diarrhea, or sore throat. Terminal features may include bleeding from all orifices (mouth, nose, ear, anus and vagina), facial and neck oedema or pleural effusion. People of all ages, gender, and occupations were included in this study. A total of 440 patients' samples and Bio data were used for this study. The samples were analyzed for Lassa fever virus RNA using Real Time Reverse Transcriptase Polymerase Chain Reaction. The data obtained were analyzed using SPSS 20.0 and version 7 of Epi-Info statistical software. Analysis of these samples showed LASV prevalence of 25.7%. Chi-square analysis (p ≤ 0.05) showed that LASV infection does not depend on age, gender, or occupation. Our research re-emphasized the fact that LASV is a serious cause of fatality in humans. Our data showed that among 327 negative patients, 19 died. On the contrary, 113 LASV confirmed positive cases had 42 deaths. This result is highly significant. More so, Lassa fever disease outcome was compared across gender. There was no significant difference between the two genders. Death or recovery from LF infection does not depend on sex. However, recovery from LF significantly depends on age of the patient. Fatal outcome is significantly higher among adults/elderly. We aim to raise awareness to the recurrence of LASV in Ebonyi State and urgent need for other medical interventions, including other therapeutic measures, and possible vaccine production, considering the impact of this virus.

Development of an RT-LAMP assay for the detection of Lassa viruses in southeast and south-central Nigeria.

Lassa virus (LASV) causes Lassa fever (LF), a viral hemorrhagic fever endemic in West Africa. LASV strains are clustered into six lineages according to their geographic location. To confirm a diagnosis of LF, a laboratory test is required. Here, a reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay using a portable device for the detection of LASV in southeast and south-central Nigeria using three primer sets specific for strains clustered in lineage II was developed. The assay detected in vitro transcribed LASV RNAs within 23 min and was further evaluated for detection in 73 plasma collected from suspected LF patients admitted into two health settings in southern Nigeria. The clinical evaluation using the conventional RT-PCR as the reference test revealed a sensitivity of 50% in general with 100% for samples with a viral titer of 9500 genome equivalent copies (geq)/mL and higher. The detection limit was estimated to be 4214 geq/mL. The assay showed 98% specificity with no cross-reactivity to other viruses which cause similar symptoms. These results suggest that this RT-LAMP assay is a useful molecular diagnostic test for LF during the acute phase, contributing to early patient management, while using a convenient device for field deployment and in resource-poor settings.

Prevalence of helminth infestation during pregnancy and its association with maternal anemia and low birth weight.

OBJECTIVE: To determine the prevalence of helminth infestation during pregnancy and the associated risks of adverse maternal and infant outcomes. METHODS: A cross-sectional study of women with a singleton pregnancy of at least 34 weeks was conducted at a teaching hospital in Benin City, Nigeria, between April 1 and September 30, 2010. Socioeconomic and clinical data were obtained. Stool samples were used to determine helminth infection. Birth weight was recorded at delivery. Multivariable analysis was used to assess the link between helminth infestation and maternal and perinatal outcomes. RESULTS: Among 178 women, 31 (17.4%) had a helminth infestation (15 [8.4%] had ascariasis, 8 [4.5%] trichuriasis, and 25 [14.0%] hookworm infestation). Multivariate analysis found that helminth infestations was associated with maternal anemia (adjusted odds ratio 12.4; 95% confidence interval 4.2-36.3) and low birth weight (adjusted odds ratio 6.8; 95% confidence interval 2.1-21.9). CONCLUSION: Approximately one in five women had a helminth infestation in the third trimester of pregnancy. Maternal helminth infestation significantly increased the risks of maternal anemia and low birth weight, indicating that routine administration of anthelminthic drugs during early pregnancy might improve perinatal outcomes.

Prevalence of parasitemia and associated immunodeficiency among HIV-malaria co-infected adult patients with highly active antiretroviral therapy.

OBJECTIVE: To investigate the malaria parasitemia, CD4(+) cell counts and some haematological indices among HIV-malaria co-infected adult patients with highly active antiretroviral therapy (HAART). METHODS: A total of 342 adult HIV positive subjects were recruited at the consultant outpatient HIV/AIDS clinic, University of Benin Teaching Hospital, Benin City, Nigeria between June 2011 to November 2011. Blood samples were taken for malaria parasite count, CD4(+) cell count and other haematological counts. RESULTS: Out of the 342 adult HIV positive subjects a total of 254 patients (74.3%) were found to have malaria parasitemia. The incidence of malaria parasitemia increased with advancing clinical stage of HIV infection and this was statistically significant (P=0.002). There was no statistical significance when gender was compared with the HIV-malaria status (P >0.05). Of the 254 co-infected patients, 134 (52.8%) had high parasitemia (>1.25 × 10(9)/L). Sixty patients were found to be hyperparasitemic (>2.5 parasites/L). There was a significant association between CD4(+) cell count and having significant parasitemia (P < 0.000 1). About half (50.8%) of co-infected patients had CD4(+) cell count ≤ 200/µL, and majority (44.9%) of this population also had significant parasitemia. Anaemia and thrombocytopenia were not significantly associated with HIV-malaria co-infection (P > 0.05). CONCLUSIONS: The prevalence of parasitemia is high among the HIV/AIDS infected patients.