Ebola is a deadly disease which affects humans and certain animals. The causative agents for Ebola Virus Disease (EVD) belongs to the genus Ebolavirus. Of the viruses in this family only four namely Ebola, Sudan, Tai Forest, and Bundibugyo are known to cause this disease.
Animal to Human Transmission of EBD
Ebola virus is animal-borne. Fruit bats are its prime carriers who transmit it to animals like apes, monkeys etc. Zoonotic transmission to humans occurs through inadvertent contact with bodily secretions and tissues of infected sick or dead animals.
Human to Human Transmission of EBD
Within humans, the virus transmission is through direct contact via injured skin or mucous membranes of eyes, nose, and mouth with
- Infected living or dead person’s bodily secretions which include saliva, mucus, vomit, urine, semen, feces or blood
- Contaminated articles like clothing, medical equipment or surfaces in contact with the infected living or dead person
- Sexual contact with an infected
Symptoms of EBD
The symptoms manifest between 2 to 21 days after infection with the virus. Initial symptoms include a sore throat, fever, headache, muscle pain, fatigue. This is then followed by vomiting, diarrhea, abdominal pain, dysfunctions of liver and kidneys, with internal and external hemorrhage. Decreased white blood cells (WBC) and platelet counts and elevated liver enzymes readings are reported.
Diagnosis in the initial stage is quite difficult as the symptoms mimic other common diseases like malaria, meningitis or typhoid. Various diagnostic tests are available that can help confirm the presence of the disease.
There is no effective treatment for Ebola so far. However, there are a number of drug and immune therapies which are undergoing clinical trials.
Factors for its Rapid Spread
- Failure in regulating human encroachment on the wild forest areas resulted in the zoonotic transmission of the virus to humans.
- The absence of approved antivirals and vaccines to fight the Ebola virus, underdeveloped healthcare systems, and infrastructure, bad governance, shortage of funds are some main factors.
- In countries having endemic infectious diseases like malaria, meningitis etc, the diagnosis of Ebola could not be made in the early stages of the disease as its symptoms are similar to those diseases.
- The early outbreaks of Ebola were restricted to rural areas in Africa. However, the latest outbreaks spread to the thickly populated cities and slum areas made it difficult to confine the spread of Ebola.
- Unchecked population movement across international borders posed a grave risk of transmission of the virus to other nations. Ineffective screening of suspected sick travelers at international airports increased the risk.
- In some places, as the risk perception of outbreak reduced, stringent procedures for patient handling, hygiene etc were not strictly followed. Many health workers got infected and deaths followed.
- In some areas of Africa, funeral practices that involve contact with infected corpses and the dependence of poor on traditional healers for treatment have caused further outbreaks.
- The international response to these outbreaks in terms of medical supplies, precaution equipment, trained medical teams etc could not keep up with the rising outbreaks of the disease across a wide geographical area.