Write a short note on viral haemorrhagic fevers, including Ebola virus disease.

Definition

Viral haemorrhagic fevers (VHFs) are a group of severe systemic illnesses caused by RNA viruses from four families, characterised by fever, increased vascular permeability, coagulopathy and multi-organ dysfunction, with a variable tendency to bleeding. They are of major public health importance because several are highly transmissible, have high case fatality, and have epidemic potential.

Indian relevance: dengue is endemic nationwide; Crimean-Congo haemorrhagic fever has caused outbreaks in Gujarat and Rajasthan with nosocomial transmission to healthcare workers; and Kyasanur Forest disease ("monkey fever") is endemic in the Western Ghats, particularly Karnataka, transmitted by ticks with monkeys as amplifying hosts, and is preventable by vaccination in endemic areas. Nipah virus (a paramyxovirus, not strictly a VHF but managed with the same precautions) has caused outbreaks in Kerala with high mortality.

Pathogenesis

Viral replication in dendritic cells and macrophages causes impaired interferon response and immune dysregulation, with massive cytokine release, endothelial injury and increased vascular permeability, platelet dysfunction and consumption, and disseminated intravascular coagulation with hepatic dysfunction reducing clotting factor synthesis. Death results from shock and multi-organ failure, more often than from exsanguination — a point frequently misunderstood.

Clinical Features — a Common Pattern

• Non-specific prodrome: abrupt fever, severe headache, myalgia and profound prostration, sore throat, conjunctival injection, and often a maculopapular rash.
• Gastrointestinal: nausea, vomiting, profuse watery diarrhoea and abdominal pain — in Ebola these dominate and cause massive fluid loss.
• Haemorrhagic phase (in a minority — under half in Ebola): petechiae, purpura, mucosal bleeding from gums and injection sites, haematemesis, melaena, haematuria.
• Organ dysfunction: hepatitis, acute kidney injury, encephalopathy, and shock with multi-organ failure.
• Recovery, when it occurs, is slow, with prolonged weakness; survivors of Ebola may have persistent virus in immune-privileged sites (eye, CNS, testis) with uveitis, and sexual transmission months after recovery.

Ebola Virus Disease — Specifics

• Incubation 2–21 days. The patient is not infectious until symptomatic — a fact central to contact tracing and quarantine policy.
• Transmission is by direct contact with blood, body fluids, or contaminated materials of a symptomatic or deceased patient, and through unsafe burial practices, which have driven several epidemics. It is not airborne.
• Healthcare workers are at very high risk, and nosocomial amplification has been a feature of every major outbreak.
• Case fatality has ranged from about 25% to 90% across outbreaks, dependent on strain and quality of supportive care.
• Vaccines (rVSV-ZEBOV) and monoclonal antibody treatments now exist and have substantially altered outbreak management.

Investigations

• Alert the laboratory before sending any sample — VHF specimens require high-level containment (BSL-3/4) and must be handled by trained staff with strict protocols.
• RT-PCR is the diagnostic test of choice; antigen detection ELISA; IgM/IgG serology later in the illness; viral culture only in reference laboratories.
• Supporting tests: CBC (leucopenia then leucocytosis, thrombocytopenia), coagulation profile with D-dimer (DIC), transaminases (markedly raised, with AST > ALT), renal function and electrolytes, blood glucose, arterial blood gas.
• Exclude the treatable mimics urgently and in parallel — malaria above all, and also typhoid, leptospirosis, meningococcaemia, rickettsial disease, dengue and severe sepsis. A patient with fever returning from an endemic area has malaria until proved otherwise, and missing it while focusing on VHF is a real risk.

Management

1. Isolation and infection control — the immediate priority

• Isolate the patient in a single room with dedicated equipment and restricted, logged staff access.
• Full personal protective equipment — impermeable gown, double gloves, face shield or goggles, N95 respirator, boots — with supervised donning and, critically, doffing, which is when most healthcare worker infections occur.
• Safe handling of sharps and body fluids; disinfection with appropriate agents; safe and dignified burial practices.
• Notify public health authorities immediately and initiate contact tracing with 21-day monitoring of contacts.

2. Supportive care — the mainstay, and the intervention that most improves survival

• Aggressive fluid and electrolyte replacement — in Ebola, losses from vomiting and diarrhoea are enormous, and good fluid management markedly reduces mortality.
• Correct electrolyte disturbance, particularly potassium; monitor glucose.
• Blood and blood product transfusion for bleeding and coagulopathy.
• Organ support — oxygen, renal replacement therapy, vasopressors as needed.
• Treat co-infections empirically — antimalarials and broad-spectrum antibiotics, because co-infection is common and clinical distinction is impossible.
• Antipyretics and analgesia — avoid NSAIDs and aspirin, which worsen bleeding risk.

3. Specific therapy

Monoclonal antibody preparations for Ebola; ribavirin for Lassa fever and CCHF (most effective given early); vaccination for Ebola (including ring vaccination of contacts), yellow fever, and KFD in endemic districts of Karnataka.