Trend of Lassa fever cases and factors associated with mortality in Liberia, 2016 - 2021: a secondary data analysis.

Introduction: Lassa fever (LF) is endemic in Liberia and is immediately reportable. Suspected cases are confirmed at the National Public Health Reference Laboratory. However, there is limited information on the trend and factors associated with mortality. We described the epidemiological characteristics of LF cases and determined factors associated with mortality in Liberia from 2016 to 2021. Methods: we reviewed 867 case-based LF surveillance data from 2016 to 2021 obtained from the National Public Health Institute of Liberia (NPHIL). The cases that met the suspected LF case definition were tested with RT-PCR. Using Epi Info 7.2.5.0. We conducted univariate, bivariate, and multivariate and analysis. We calculated frequencies, proportions. Positivity rate, case fatality rate, and factors associated with LF mortality using chi-square statistics and logistics regression at 5% level of significance. Results: eighty-five percent (737/867) of the suspected cases were tested and 26.0% (192/737) were confirmed LF positive. The median age of confirmed LF cases was 21(IQR: 12-34) years. Age 10-19 years accounted for 24.5% (47/192) and females 54.2% (104/192). Bong 33.9% (65/192), Grand Bassa 31.8% (61/192), and Nimba counties, 21.9% (42/192) accounted for most of the cases. The median duration from symptom onset to hospital admission was 6 (IQR: 3-9) days. A majority, 66% (126/192) of the cases were reported during the dry season (October-March) and annual incidence was highest at 12 cases per 1,000,000 population in 2019 and 2020. The overall case fatality rate was 44.8%. Non-endemic counties, Margibi, 77.8% and Montserrado, 66.7% accounted for the highest case fatality rate (CFR), while 2018, 66.7% and 2021, 60.0% recorded the highest CFR during the period. Age ≥30 years (aOR=2.1,95% CI: 1.08-4.11, p=0.027) and residing in Grand Bassa County (aOR=0.3, 95% CI: 0.13-0.73, p=0.007) were associated with LF mortality. Conclusion: Lassa fever was endemic in three of the fifteen counties of Liberia, case fatality rate remained generally high and widely varied. The high fatality of LF has been reported to the NPHIL and is currently being further investigated. There is a need to continuously train healthcare workers, especially in non-endemic counties to improve the LF treatment outcome.

Strengthening laboratory biosafety in Liberia during the COVID-19 pandemic: Experience from the Global Laboratory Leadership Programme.

Background: The Global Laboratory Leadership Programme (GLLP) has biosafety and biosecurity as one of its core competencies and advocates for a One Health approach involving all relevant sectors across the human-animal-environment interface to empower national laboratory systems and strengthen health security. Decentralization of SARS-CoV-2 testing in Liberia coupled with an increase in the number of COVID-19 infections among laboratory professionals raised biosafety concerns. In response, a set of trainings on laboratory biosafety was launched for lab personnel across the country under the framework of the GLLP. The goal was to deliver a comprehensive package for laboratory biosafety in the context of SARS-CoV-2 through active learning. Methods: Three one-day workshops were conducted between September and October 2020, training personnel from human, animal and environmental laboratories through a One Health approach. Concepts critical to laboratory biosafety were delivered in an interactive engagement format to ensure effective learning and retention of concepts. Pre- and post-training assessments were performed, and a paired t-test was used to assess knowledge gain. Results: Of the 67 participants, 64 were from the human health sector, one from veterinary sector and two from environmental health sector. The average pre-test score was 41%. The main gaps identified were failure to acknowledge surgical antisepsis as a form of hand hygiene and recognition of PPE as the best risk control measure. The average post-test score was 75.5%. The mean difference of pre-test and post-test scores was statistically significant (p-value <0.001). Participants indicated satisfaction with the workshop content, mode of delivery and trainers' proficiency. Conclusions: The workshops were impactful as evidenced by significant improvement (34.5%) in the post-test scores and positive participant feedback. Repeated refresher trainings are vital to addressing the gaps, ensuring compliance, and promoting biosafety culture. GLLP's approach to cultivating multisectoral national laboratory leaders ready to take responsibility and ownership for capacity building provides a sustainable solution for attaining strong national laboratory systems better prepared for health emergencies and pandemics like COVID-19.

Epidemiological characteristics of Lassa fever cases in Liberia: a retrospective analysis of surveillance data, 2019-2020.

OBJECTIVES: Liberia is endemic to Lassa fever (LF) and has the largest reported per capita incidence of LF patients in the West African region. Cases of the disease increased unprecedentedly in 2019 and 2020, characterized by a geographical drift in epidemiology and seasonal variation of occurrence. This study aims to describe the epidemiological and clinical characteristics of LF in Liberia from 2019 to 2020. METHODS: A retrospective study was conducted on cases of LF confirmed at the National Public Health Reference Laboratory from January 2019 to December 2020. Medical records were reviewed, and epidemiological and clinical data were collected in an organized manner. Descriptive and inferential statistics were carried out using Epi Info (version 7.2.5.0). RESULTS: A total of 382 suspected LF cases were reported, of which 103 were laboratory-confirmed, yielding a case positivity rate of 27% (103/382). The median age of the LF cases was 20 (IQR: 9-30). Children younger than 18 years accounted for 40.8% (42/103) of the cases and healthcare workers' cases constituted 7.7% of the cases. Bong, Nimba, and Grand Bass accounted for 87.4% of the cases with cases in new counties like Lofa, Margibi, and Grand Kru. Hemorrhage (aOR:10.2; 95% CI: 3.11-33.81), patients who did not receive ribavirin (aOR: 4.4; 95% CI: 1.12-17.57, P = 0.034), and patients aged 40 years or older (aOR: 6.2; 95% CI: 1.19-32.53, P = 0.049) were associated with LF mortality. CONCLUSION: The LF cases in 2019 and 2020 had a high case fatality rate and spread to new counties that had not previously reported LF. The disease occurred during most of the rainy season instead of the usual dry season. There is an urgent need to lower morbidity and mortality, improve early presentation to the hospital, and early initiation of appropriate medical care.

Artesunate-amodiaquine and artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in Liberia: in vivo efficacy and frequency of molecular markers.

BACKGROUND: Artesunate-amodiaquine (ASAQ) and Artemether-lumefantrine (AL) are the recommended treatment for uncomplicated Plasmodium falciparum malaria in Liberia. Intermittent preventive treatment with sulfadoxine/pyrimethamine is also recommended for pregnant women. The therapeutic efficacy of Artesunate-amodiaquine and Artemether-lumefantrine, and the frequency of molecular markers associated with anti-malarial drug resistance were investigated. METHODS: The therapeutic efficacy of ASAQ and AL was evaluated using the standard World Health Organization protocol (WHO. Methods for Surveillance of Antimalarial Drug Efficacy. Geneva: World Health Organization; 2009. https://www.who.int/malaria/publications/atoz/9789241597531/en/ ). Eligible children were recruited and monitored clinically and parasitologically for 28 days. Polymorphisms in the Pfkelch 13, chloroquine resistance transporter (Pfcrt), multidrug resistance 1 (Pfmdr-1), dihydrofolate reductase (Pfdhfr), and dihydropteroate synthase (Pfdhps) genes and copy number variations in the plasmepsin-2 (Pfpm2) gene were assessed in pretreatment samples. RESULTS: Of the 359 children enrolled, 180 were treated with ASAQ (89 in Saclepea and 91 in Bensonville) and 179 with AL (90 in Sinje and 89 in Kakata). Of the recruited children, 332 (92.5%) reached study endpoints. PCR-corrected per-protocol analysis showed ACPR of 90.2% (95% CI: 78.6-96.7%) in Bensonville and 92.7% (95% CI: 83.4.8-96.5%) in Saclepea for ASAQ, while ACPR of 100% was observed in Kakata and Sinje for AL. In both treatment groups, only two patients had parasites on day 3. No artemisinin resistance associated Pfkelch13 mutations or multiple copies of Pfpm2 were found. Most samples tested had the Pfcrt 76 T mutation (80/91, 87.9%), while the Pfmdr-1 86Y (40/91, 44%) and 184F (47/91, 51.6%) mutations were less frequent. The Pfdhfr triple mutant (51I/59R/108 N) was the predominant allele (49.2%). For the Pfdhps gene, it was the 540E mutant (16.0%), and the 436A mutant (14.3%). The quintuple allele (51I/59R/108 N-437G/540E) was detected in only one isolate (1/357). CONCLUSION: This study reports a decline in the efficacy of ASAQ treatment, while AL remained highly effective, supporting the recent decision by NMCP to replace ASAQ with AL as first-line treatment for uncomplicated falciparum malaria. No association between the presence of the mutations in Pfcrt and Pfmdr-1 and the risk of parasite recrudescence in patients treated with ASAQ was observed. Parasites with signatures known to be associated with artemisinin and piperaquine resistance were not detected. The very low frequency of the quintuple Pfdhfr/Pfdhps mutant haplotype supports the continued use of SP for IPTp. Monitoring of efficacy and resistance markers of routinely used anti-malarials is necessary to inform malaria treatment policy. Trial registration ACTRN12617001064392.

Lassa virus circulating in Liberia: a retrospective genomic characterisation.

BACKGROUND: An alarming rise in reported Lassa fever cases continues in west Africa. Liberia has the largest reported per capita incidence of Lassa fever cases in the region, but genomic information on the circulating strains is scarce. The aim of this study was to substantially increase the available pool of data to help foster the generation of targeted diagnostics and therapeutics. METHODS: Clinical serum samples collected from 17 positive Lassa fever cases originating from Liberia (16 cases) and Guinea (one case) within the past decade were processed at the Liberian Institute for Biomedical Research using a targeted-enrichment sequencing approach, producing 17 near-complete genomes. An additional 17 Lassa virus sequences (two from Guinea, seven from Liberia, four from Nigeria, and four from Sierra Leone) were generated from viral stocks at the US Centers for Disease Control and Prevention (Atlanta, GA) from samples originating from the Mano River Union (Guinea, Liberia, and Sierra Leone) region and Nigeria. Sequences were compared with existing Lassa virus genomes and published Lassa virus assays. FINDINGS: The 23 new Liberian Lassa virus genomes grouped within two clades (IV.A and IV.B) and were genetically divergent from those circulating elsewhere in west Africa. A time-calibrated phylogeographic analysis incorporating the new genomes suggests Liberia was the entry point of Lassa virus into the Mano River Union region and estimates the introduction to have occurred between 300-350 years ago. A high level of diversity exists between the Liberian Lassa virus genomes. Nucleotide percent difference between Liberian Lassa virus genomes ranged up to 27% in the L segment and 18% in the S segment. The commonly used Lassa Josiah-MGB assay was up to 25% divergent across the target sites when aligned to the Liberian Lassa virus genomes. INTERPRETATION: The large amount of novel genomic diversity of Lassa virus observed in the Liberian cases emphasises the need to match deployed diagnostic capabilities with locally circulating strains and underscores the importance of evaluating cross-lineage protection in the development of vaccines and therapeutics. FUNDING: Defense Biological Product Assurance Office of the US Department of Defense and the Armed Forces Health Surveillance Branch and its Global Emerging Infections Surveillance and Response Section.

Rapid Laboratory Identification of Neisseria meningitidis Serogroup C as the Cause of an Outbreak - Liberia, 2017.

On April 25, 2017, a cluster of unexplained illness and deaths among persons who had attended a funeral during April 21-22 was reported in Sinoe County, Liberia (1). Using a broad initial case definition, 31 cases were identified, including 13 (42%) deaths. Twenty-seven cases were from Sinoe County (1), and two cases each were from Grand Bassa and Monsterrado counties, respectively. On May 5, 2017, initial multipathogen testing of specimens from four fatal cases using the Taqman Array Card (TAC) assay identified Neisseria meningitidis in all specimens. Subsequent testing using direct real-time polymerase chain reaction (PCR) confirmed N. meningitidis in 14 (58%) of 24 patients with available specimens and identified N. meningitidis serogroup C (NmC) in 13 (54%) patients. N. meningitidis was detected in specimens from 11 of the 13 patients who died; no specimens were available from the other two fatal cases. On May 16, 2017, the National Public Health Institute of Liberia and the Ministry of Health of Liberia issued a press release confirming serogroup C meningococcal disease as the cause of this outbreak in Liberia.

Lateral Flow Immunoassays for Ebola Virus Disease Detection in Liberia.

BACKGROUND: Lateral flow immunoassays (LFIs) are point-of-care diagnostic assays that are designed for single use outside a formal laboratory, with in-home pregnancy tests the best-known example of these tests. Although the LFI has some limitations over more-complex immunoassay procedures, such as reduced sensitivity and the potential for false-positive results when using complex sample matrices, the assay has the benefits of a rapid time to result and ease of use. These benefits make it an attractive option for obtaining rapid results in an austere environment. In an outbreak of any magnitude, a field-based rapid diagnostic assay would allow proper patient transport and for safe burials to be conducted without the delay caused by transport of samples between remote villages and testing facilities. Use of such point-of-care instruments in the ongoing Ebola virus disease (EVD) outbreak in West Africa would have distinct advantages in control and prevention of local outbreaks, but proper understanding of the technology and interpretation of results are important. METHODS: In this study, a LFI, originally developed by the Naval Medical Research Center for Ebola virus environmental testing, was evaluated for its ability to detect the virus in clinical samples in Liberia. Clinical blood and plasma samples and post mortem oral swabs submitted to the Liberian Institute for Biomedical Research, the National Public Health Reference Laboratory for EVD testing, were tested and compared to results of real-time reverse transcription-polymerase chain reaction (rRT-PCR), using assays targeting Ebola virus glycoprotein and nucleoprotein. RESULTS: The LFI findings correlated well with those of the real-time RT-PCR assays used as benchmarks. CONCLUSIONS: Rapid antigen-detection tests such as LFIs are attractive alternatives to traditional immunoassays but have reduced sensitivity and specificity, resulting in increases in false-positive and false-negative results. An understanding of the strengths, weaknesses, and limitations of a particular assay lets the diagnostician choose the correct situation to use the correct assay and properly interpret the results.

Molecular Evidence of Sexual Transmission of Ebola Virus.

A suspected case of sexual transmission from a male survivor of Ebola virus disease (EVD) to his female partner (the patient in this report) occurred in Liberia in March 2015. Ebola virus (EBOV) genomes assembled from blood samples from the patient and a semen sample from the survivor were consistent with direct transmission. The genomes shared three substitutions that were absent from all other Western African EBOV sequences and that were distinct from the last documented transmission chain in Liberia before this case. Combined with epidemiologic data, the genomic analysis provides evidence of sexual transmission of EBOV and evidence of the persistence of infective EBOV in semen for 179 days or more after the onset of EVD. (Funded by the Defense Threat Reduction Agency and others.).

Monitoring of Ebola Virus Makona Evolution through Establishment of Advanced Genomic Capability in Liberia.

To support Liberia's response to the ongoing Ebola virus (EBOV) disease epidemic in Western Africa, we established in-country advanced genomic capabilities to monitor EBOV evolution. Twenty-five EBOV genomes were sequenced at the Liberian Institute for Biomedical Research, which provided an in-depth view of EBOV diversity in Liberia during September 2014-February 2015. These sequences were consistent with a single virus introduction to Liberia; however, shared ancestry with isolates from Mali indicated at least 1 additional instance of movement into or out of Liberia. The pace of change is generally consistent with previous estimates of mutation rate. We observed 23 nonsynonymous mutations and 1 nonsense mutation. Six of these changes are within known binding sites for sequence-based EBOV medical countermeasures; however, the diagnostic and therapeutic impact of EBOV evolution within Liberia appears to be low.