Literature-informed probability scoring for research and method evaluation. Not validated for diagnosis, triage, treatment, or point-of-care use.
⚠ Important safety information — read before use
This tool does not diagnose Lassa fever. It provides probability estimates to support clinical decision-making. All results require laboratory RT-PCR confirmation. Probability estimates are based on published clinical literature and must not replace clinical judgment.
Report any suspected case to NCDC immediately — do not wait for laboratory results before notifying.
For your own reference only — not currently factored into the probability below.
Section 2 — Major symptoms (higher specificity for Lassa fever)
Section 3 — Other symptoms
Section 4 — Exposure history (last 21 days)
Probability estimate
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Probability estimate based on symptom weights informed by published Lassa fever clinical literature. All results require laboratory RT-PCR confirmation. This is not a diagnostic result.
Risk category and recommended action
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Differential — conditions to consider
Relative likelihoods in a febrile patient presenting in Nigeria. These are illustrative estimates to support the workup, not validated diagnostic probabilities. Lassa fever co-infection with malaria is common and does not exclude either condition.
Recommended clinical actions
☐Place patient in single-room isolation
☐Use full PPE: gloves, gown, N95/FFP2 mask, eye protection
☐Collect blood sample for Lassa RT-PCR (contact NCDC for nearest lab)
☐Notify state epidemiologist now
☐Report to NCDC: 0800-970000-10
☐Document full exposure history and potential contact list
☐If RT-PCR will be delayed more than 24 hours and clinical suspicion remains very high: discuss empirical ribavirin with a senior clinician and NCDC — do not administer without senior clinical oversight.
Medical disclaimer. This prototype provides research-use probability estimates only and does not constitute a medical diagnosis, clinical advice, triage recommendation, or treatment recommendation. The scoring approach is informed by published Lassa fever literature but has not been prospectively validated for clinical use. It must not be used to make patient-care decisions; qualified healthcare professionals should follow approved local protocols and laboratory confirmation.
Data privacy. No symptom data entered in this form is transmitted to any server. All calculations run entirely in your browser. Nothing is stored or logged.