Ebola Virus Disease Overview

Ebola Virus Disease (EVD)

• EVD is a severe and often deadly disease, but recovery depends on clinical care and immune response.
• Similar symptoms to EVD include influenza, malaria, and typhoid fever, complicating diagnosis.
• Survivors retain antibodies for up to 10 years, suggesting protective immunity to the specific Ebola strain that infected them.

Transmission

• Initial infection occurs through contact with infected animals, like fruit bats or nonhuman primates, in a spillover event.
• Human-to-human transmission occurs through direct contact with:
  • Blood or body fluids from infected individuals.
  • Contaminated objects.
  • Infected animals.
  • Semen from male survivors, possibly for extended periods post-recovery.
• Women do not transmit Ebola through vaginal fluids after recovery.
• Spread only occurs after the symptomatic onset; there’s no evidence of transmission via insects.

Signs and Symptoms

• Symptoms may manifest 2 to 21 days post-exposure, typically average around 8 to 10 days.
• Initial "dry" symptoms include:
  • Fever
  • Severe headache
  • Muscle and joint pains
  • Weakness and fatigue
  • Sore throat
  • Loss of appetite
• Later "wet" symptoms progress to gastrointestinal issues like abdominal pain, diarrhea, and vomiting, alongside unexplained bleeding or bruising.
• Additional symptoms may include red eyes, skin rash, and hiccups, especially in late-stage infections.

Diagnosis

• Diagnosis requires a combination of specific symptoms and exposure history within the last 21 days.
• Ebola virus can be detected in blood after symptoms start, typically taking up to three days after onset for detectable levels.
• Polymerase chain reaction (PCR) is the primary diagnostic method due to its sensitivity.

Drug Treatments

• Inmazeb™ is the first approved treatment (October 2020), made of three monoclonal antibodies (mAbs).
• mAbs act against the glycoprotein on the Ebola virus, preventing its entry into human cells.
• Common side effects of Ebanga treatment include fever, tachycardia, diarrhea, and chills, which overlap with EVD symptoms.
• Discontinue Ebanga in case of hypersensitivity reactions.

Avian Influenza

• Avian influenza primarily impacts the respiratory tract and can result in high mortality rates.
• Caused mainly by influenza A, with influenza B contributing to milder cases.
• Seasonal variation in the virus's hemagglutinin and neuraminidase glycoproteins leads to yearly intensity fluctuation.
• Human infections often stem from contact with sick poultry, particularly in Southeast Asia, with limited person-to-person transmission.
• Symptoms typically appear 1–3 days after exposure, leading to fever, malaise, and cough, with possible severe complications such as viral pneumonia and respiratory failure.

This quiz covers important information about Ebola virus disease (EVD), including its symptoms and comparison to common illnesses like influenza and malaria. It also discusses recovery and the immune response in survivors. Test your knowledge on this severe and often deadly disease.