Ebola virus is suspected to be zoonotic, transmitted from bats and primates to humans through contact with bodily fluids. It infects macrophages, causing them to release cytokines that produce symptoms like fever and vascular problems. This leads to small blood clots, disruption of coagulation, bleeding, and multi-organ failure. The incubation period is 2-21 days on average. Laboratory diagnosis involves non-specific tests like leukopenia and elevated liver enzymes, as well as specific tests detecting the virus's RNA, proteins, or antibodies.

1. Pathogenesis and Lab diagnosis
of Ebola virus
Dr. Pendru Raghunath

2. Pathogenesis
Suspected to be a zoonotic
(animal-borne)
Suspected reservoirs
Bats
Primates (in some cases, have
been confirmed)

3. Mode of infection
1. Direct contact with contaminated human body fluids such as
blood, urine, vomitus, faeces and semen
2. Contact with contaminated medical products such as
syringe needles
3. Consumption of wild animal meat (“bush meat”)

4. Pathogenesis

5. • Macrophages infected with
Ebola virus produce different
cytokines and nitric oxide (NO)
.
• Breakdown products of
necrotic cells also stimulate
the release of the same
cytokines
• These cytokines are
responsible for the fever,
malaise, vasodilatation,
increased vascular
permeability, hypotension,
and shock of ebola virus
disease

6. • Virus-infected macrophages
synthesize cell-surface tissue
factor (TF), triggering the
extrinsic coagulation pathway
• Liver dysfunction and protein
C synthesis inhibited
• Small blood clots form in
vessels
• Consume all the available
coagulation proteins and
platelets
• Normal coagulation is
disrupted, this leads to
abnormal bleeding
• Disruption of normal blood
flow to organs and multi organ
failure

8. Incubation period
• Patients with Ebola virus disease typically have an abrupt
onset of symptoms 8 to 10 days after exposure (range 2 to
21 days)
• The incubation period for the individual patient depends, in
part, upon the type of exposure (eg, approximately 6 days
for percutaneous exposure versus 10 days for contact
exposure).

9. Clinical manifestations
 Patients with Ebola virus disease initially present with non-specific
influenza-like symptoms and can progress to
multiorgan failure and septic shock
• Stage I (unspecific):
-Extreme asthenia (body weakness)
- headache
- arthralgia (neuralgic pain in joints)
- myalgia (muscular pain or tenderness), back pain
-High fever
- Nonproductive cough and pharyngitis
-diarrhea, nausea and vomiting, anorexia
abdominal pain
- dysphagia (difficulty in swallowing)

10. Late Symptoms
Stage II (specific)
 Bleeding from eyes, ears, and nose
 Bleeding from the mouth and rectum (gastrointestinal bleeding)
 Neuropsychiatric abnormalities (depression)
 Anuria (the absence of urine formation)
 Hiccups
 Eye inflammation (conjunctivitis)
 Genital swelling (labia and scrotum)
 Increased feeling of pain in skin
 Rash over the entire body that often contains blood
 Mucosal redness of the oral cavity
 Seizures, coma, delirium

11. Laboratory diagnosis
• Non-specific methods
• Specific methods

12. Non-specific methods
• Leukopenia — Leukopenia usually presents as lymphopenia
and is then followed by an elevated neutrophil count, with an
increased percentage of immature forms
• Thrombocytopenia — Platelet counts are usually in the range
of 50,000 to 100,000/μl
• Transaminitis —Elevated serum aspartate aminotransferase
(AST) and alanine aminotransferase (ALT) levels
• Coagulation abnormalities — Prothrombin (PT) and partial
thromboplastin times (PTT) are prolonged
• Renal abnormalities — Proteinuria is a common finding, and
renal insufficiency occurs with progression of illness.

13. Specific methods
• The diagnosis is confirmed by isolating the virus, detecting its
RNA or proteins, or detecting antibodies against the virus in a
person's blood
• Isolating the virus by cell culture, detecting the viral RNA
by polymerase chain reaction (PCR) and detecting proteins
by ELISA is effective early and in those who have died from the
disease
• Virions can be seen and identified in cell culture by electron
microscopy due to their unique filamentous shapes, but
electron microscopy cannot tell the difference between the
various filoviruses despite there being some length differences.
• Detecting antibodies against the virus is effective late in the
disease and in those who recover.

14. Immunochromatographic method