Co-Infection of Lassa Fever-Malaria (LF) in Endemic Settings: Influence on LF Case Detection in Health Facilities in Ondo State, Nigeria
Abstract:
In malaria-endemic settings, a positive malaria result may explain fever while Lassa fever (LF) remains clinically possible. This study assessed LF-malaria co-infection, probable missed LF suspicion, and diagnostic delays in selected health facilities in Ondo State, Nigeria. A convergent mixed-methods design combined retrospective review of 463 LF and malaria records from 2021 – 2023 across 10 purposively selected facilities in five high-burden LGAs with nine key-informant interviews. Co-infection required positive LF and malaria laboratory results. Quantitative data were analysed using descriptive statistics, chi-square tests and logistic regression; qualitative findings were analysed thematically and integrated through a joint display. All 463 records were purposefully selected as confirmed LF cases. Of these, 297 (64.1%) had positive LF and malaria results. Malaria was suspected in 440 (95.0%) records, and 324 (70.0%) had prior malaria treatment. Probable missed LF suspicion occurred in 103 (22.2%) records. Malaria positivity was associated with missed suspicion (adjusted odds ratio [aOR] 5.30, 95% CI 2.13–13.19; p < 0.001). Interviews highlighted symptom overlap, malaria-first reasoning, treatment failure, restricted RT-PCR access, specimen-transport barriers, notification gaps and uneven refresher training. Overall, 386 (83.4%) patients recovered and 53 (11.4%) died; the case-fatality proportion among confirmed LF records was 11.4%. In this selected sample, malaria appeared to mask LF rather than establish an independent cause of mortality. Malaria confirmation should not close the LF detection pathway. Parallel assessment, timely LF specimen collection, reliable transport, effective surveillance communication and practical diagnostic algorithms may support earlier detection.References:
[1].
Akinbodewa AA, Gbala MO, Ige OO, Bello O, Akinkunmi BF,
Fabusuyi G. Lassa fever: knowledge deficits among nurses and non-nurses at a
tertiary hospital in Ondo, southwest Nigeria. Magna Sci. Adv. Biol. Pharm.
2023;9(2):14-23. Available from: https://doi.org/10.30574/msabp.2023.9.2.0026
[2].
Chandra NL, Bolt
H, Dan-Nwafor C, Ipadeola O, Ilori E, Namara G, et al. Factors
associated with delayed presentation to healthcare facilities for Lassa fever
cases, Nigeria 2019: a retrospective cohort study. BMC Infect Dis. 2021;21:143.
Available from: https://doi.org/10.1186/s12879-021-05822-4
[3].
Ilori EA, Furuse Y, Ipadeola OB, Dan-Nwafor CC, Abubakar A,
Womi-Eteng OE, et al. Epidemiologic and clinical features of Lassa fever
outbreak in Nigeria, January 1-May 6, 2018. Emerg. Infect. Dis.
2019;25(6):1066-74. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC6537738/
[4].
Ipadeola AF,
Olasehinde GI, Akinnola OO, Kolawole OM, Ejikeme AR, Ipadeola OB. Factors
associated with late presentation for Lassa fever treatment among symptomatic
cases in Ondo State, Nigeria. PAMJ One Health. 2023;10:6. Available from: https://doi.org/10.11604/pamj-oh.2023.10.6.39071
[5].
Okokhere PO,
Asogun DA, Okogbenin SA. The effect of malaria on the outcome of Lassa fever
[conference abstract]. Int. J. Infect. Dis. 2010;14(Suppl 1):e333. Available
from: https://doi.org/10.1016/j.ijid.2010.02.2233
[6].
Cadmus SI, Taiwo OJ, Akinseye VO, Cadmus EO, Famokun G,
Fagbemi S, et al. Ecological correlates and predictors of Lassa fever incidence
in Ondo State, Nigeria, 2017-2021: an emerging urban trend. Sci Rep.
2023;13:20855. Available from: https://doi.org/10.1038/s41598-023-47820-3
[7].
Asogun DA, Günther S, Akpede GO, Ihekweazu C, Zumla A. Lassa
fever: epidemiology, clinical features, diagnosis, management and prevention.
Infect. Dis. Clin. North Am. 2019;33(4):933-51. Available from: https://doi.org/10.1016/j.idc.2019.08.002
[8].
Ashcroft JW, Olayinka A, Ndodo N, Lewandowski K, Curran MD,
Nwafor CD, et al. Pathogens that cause illness clinically indistinguishable
from Lassa fever, Nigeria, 2018. Emerg Infect Dis. 2022;28(5):994-7. Available
from: https://doi.org/10.3201/eid2805.211153
[9].
Rugarabamu S, Rumisha SF, Mwanyika GO, Sindato C, Lim HY,
Misinzo G, et al. Viral haemorrhagic fevers and malaria co-infections among
febrile patients seeking health care in Tanzania. Infect Dis Poverty.
2022;11:33. Available from: https://doi.org/10.1186/s40249-022-00959-z
[10]. Oguzie JU, Petros BA, Oluniyi PE, et al. Metagenomic
surveillance uncovers diverse and novel viral taxa in febrile patients from
Nigeria. Nat Commun. 2023;14:4693. Available from: https://doi.org/10.1038/s41467-023-40247-4
[11]. Babalola SO,
Babatunde JA, Remilekun OM, Amaobichukwu AR, Abiodun AM, Jide I, et al. Lassa
virus RNA detection from suspected cases in Nigeria, 2011-2017. Pan. Afr. Med.
J. 2019;34:76. Available from: https://doi.org/10.11604/pamj.2019.34.76.16425
[12]. Raabe V,
Koehler J. Laboratory diagnosis of Lassa fever. J. Clin Microbiol.
2017;55(6):1629-37. Available from: https://doi.org/10.1128/JCM.00170-17
[13]. Croskerry P.
Clinical cognition and diagnostic error: applications of a dual process model
of reasoning. Adv. Health Sci. Educ. Theory Pract. 2009;14(Suppl 1):27-35.
Available from: https://doi.org/10.1007/s10459-009-9182-2
[14]. Donabedian A.
The quality of care: how can it be assessed? JAMA. 1988;260(12):1743-8.
Available from: https://doi.org/10.1001/jama.1988.03410120089033
[15]. Ijarotimi IT, Ilesanmi OS, Aderinwale A, Abiodun-Adewusi
O, Okon IM. Knowledge
of Lassa fever and use of infection prevention and control facilities among
health care workers during Lassa fever outbreak in Ondo State, Nigeria. Pan Afr
Med J. 2018;30:56. Available from: https://doi.org/10.11604/pamj.2018.30.56.13125
[16]. Nigeria Centre
for Disease Control and Prevention. Lassa fever situation report:
epidemiological week 13, 2024. 2024. Available from: https://www.ncdc.gov.ng/themes/common/files/sitreps/1aabc83ea46f825a772894b4a53ab870.pdf
[17]. Fetters MD,
Curry LA, Creswell JW. Achieving integration in mixed methods
designs-principles and practices. Health Serv Res. 2013;48(6 Pt 2):2134-56.
Available from: https://doi.org/10.1111/1475-6773.12117
[18]. Braun V, Clarke
V. Using thematic analysis in psychology. Qual Res Psychol. 2006;3(2):77-101. Available from: https://doi.org/10.1191/1478088706qp063oa
[19]. Tong A,
Sainsbury P, Craig J. Consolidated criteria for reporting qualitative research
(COREQ): a 32-item checklist for interviews and focus groups. Int. J. Qual.
Health Care. 2007;19(6):349-57. Available from: https://doi.org/10.1093/intqhc/mzm042
[20]. von Elm E,
Altman DG, Egger M, Pocock SJ, Gøtzsche PC, Vandenbroucke JP. The Strengthening
the Reporting of Observational Studies in Epidemiology (STROBE) statement:
guidelines for reporting observational studies. PLoS Med. 2007;4(10):e296.
Available from: https://doi.org/10.1371/journal.pmed.0040296
[21]. Enable Lassa
Research Programme (Enable 1.0) Consortium. Incidence of symptomatic Lassa
virus infection in West African countries (Enable 1.0 Lassa Research Study): a
prospective, multisite, cohort study. Lancet Glob Health. 2026;14(7):103945.
Available from: https://doi.org/10.1016/S2214-109X(26)00090-2
[22]. Okeke IN,
Manning RS, Pfeiffer T. Diagnostic schemes for reducing epidemic size of
African viral hemorrhagic fever outbreaks. J. Infect. Dev. Ctries.
2014;8(9):1148-59. Available from: https://doi.org/10.3855/jidc.4636
[23]. Oloyede TA, Omar NA, Adedire EB, Tarfa MJ, Chikwanda M,
Muhammad BA, et al. Detection timeliness and case fatality patterns of Lassa
fever in Bauchi State, Nigeria: a descriptive epidemiological analysis,
November 2024-February 2025. J. Interv. Epidemiol. Public Health. 2025;8(4):98.
Available from: https://doi.org/10.37432/jieph-d-25-00171
[24]. Adejugbagbe AM, Sunday DD, Orimolade AO, Johnson OF, Fagbemi S, Isere EE, et al. Assessment of Lassa fever reporting among healthcare workers in a Southwest state, Nigeria. Discov Public Health. 2025;22:348. Available from: https://doi.org/10.1186/s12982-025-00744-x
