Temporal Profile of Nipah Virus Infection
Incubation Period and Initial Presentation
The incubation period for Nipah virus infection ranges from 4 to 14 days following exposure, after which patients develop acute onset of fever, headache, and rapidly progressive neurological or respiratory symptoms. 1, 2, 3
Acute Phase Timeline (Days 1-7)
Early Clinical Course (First 24-48 Hours)
- Fever, headache, myalgia, and vomiting develop acutely at symptom onset 3, 4
- Respiratory symptoms may appear early, particularly in Bangladesh/India strains 4, 5
- Altered consciousness can develop within the first 24-48 hours in severe cases 2, 6
Progression to Severe Disease (Days 3-7)
- Encephalitis manifestations emerge rapidly, with myoclonic jerks showing characteristic 1:1 relationship to EEG periodic complexes 6
- Severe hypoxemia requiring mechanical ventilation typically develops within 3-7 days of symptom onset 1, 2
- Neurological deterioration with dystonia, areflexia, and hypotonia indicates poor prognosis 1, 6
Critical Decision Points
Early intubation and invasive mechanical ventilation must be initiated promptly for severe hypoxemia rather than attempting prolonged trials of non-invasive ventilation, which increase both mortality and healthcare worker exposure risk during emergency intubation. 1, 2, 6
Physiological Monitoring Timeline
- RT-PCR diagnostic testing should be performed immediately upon clinical suspicion using throat swabs, respiratory specimens, CSF, or urine 1, 2
- Continuous monitoring of vital signs, oxygen saturation, neurological status, and acid-base balance is mandatory throughout the acute phase 6
- Factors associated with poor prognosis include low/falling pH, high APACHE II score, and severe neurological manifestations 1
Convalescent Phase (Beyond 7-14 Days)
Survivors
- Serology (IgM and IgG antibodies) becomes positive during the convalescent phase but is not useful for acute diagnosis 1, 2
- 30-50% of survivors develop long-term neurological sequelae including seizures, cognitive deficits, motor weakness, and behavioral problems 2
Fatal Cases
- Case-fatality ratio ranges from 40-75%, with systematic reviews reporting 73.9% mortality 1, 2
- Death typically occurs within 7-14 days of symptom onset in fatal cases 3, 5, 7
Transmission Timeline Considerations
Person-to-person transmission occurs in approximately 50% of cases, making healthcare workers extremely high-risk throughout the entire clinical course, particularly during aerosol-generating procedures. 1, 2, 6
- Airborne precautions with N-95 respirators, gowns, aprons, and face shields are mandatory from the moment of clinical suspicion through complete recovery or death 1, 2
- Viable virus on healthcare workers' mobile phones and hospital equipment can cause nosocomial transmission, requiring continuous surface decontamination 1
- Transmission can occur after only minutes of exposure, necessitating strict precautions even during brief patient encounters 1
Common Pitfalls to Avoid
- Do not delay intubation by attempting prolonged non-invasive ventilation trials—this increases mortality and staff exposure during emergency intubation 1, 2, 6
- Do not discharge patients without comprehensive follow-up plans, as neurological sequelae may emerge later in the convalescent phase 6
- Do not underestimate transmission risk at any point during the clinical course, as person-to-person spread occurs in approximately 50% of cases 1, 2