Evidence of Ebola Viral Markers Found in Lung of Recovering Patient

Highlights

• Ebola virus causes a severe hemorrhagic fever that is often fatal with no proven treatment or vaccine.
• The pathogenesis of the infection still remains unclear; understanding the pathogenesis is critical to develop new drugs or vaccines
• Evidence for the replication of the virus in the lung during recovery has been shown by presence of viral markers.
• This finding might offer insights into the pathogenesis of the illness and help in future research activities.

Ebola virus may persist and multiply in the lungs of patients recovering from the infection, according to a recent research published in PLOS Pathogens.

Aim of the Research

Based on animal studies and observations made on evacuated patients, there have been speculations that Ebola virus might cause damage to the lungs by replicating in lung tissue. However, no evidence has been shown till now that lung is infected by the Ebola virus.

In order to determine the possible presence of the Ebola virus in the lung, Dr. Ippolito of the National Institute for Infectious Diseases "Lazzaro Spallanzani", Rome, and colleagues closely studied a single health care worker who was evacuated from Africa and underwent treatment in Rome. They looked for the presence of viral genetic material in the lung of the patient while he underwent treatment and during his recovery phase.

Details and Observations of the Research

The research team looked for the occurrence of viral RNA fragments known to be involved in viral replication and compared these levels with viral RNA markers in the blood of the patient.

They noticed that viral RNA and replication markers were present in the lung even five days after they became undetectable in the blood.  This provided undeniable evidence that the virus was present and actively replicated in the lung tissue.

What the Findings Imply

This finding is important because it might offer new understanding into the pathogenesis of the disease which remains largely unknown. Until now there has been no evidence to indicate that Ebola virus infects the lung tissue.

Earlier studies on Ebola virus disease have shown minimal or very mild changes in lungs that were not clinically significant.  Respiratory symptoms or respiratory failure is not a feature of Ebola viral illness.

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"We demonstrated a long persistence EBOV replication markers within the respiratory tract, compared to plasma," the authors explain. "This suggests a major role of the respiratory tissues in the pathogenesis of Ebola virus disease."

Ebola Virus Disease (EVD) in Brief

Ebola virus disease or Ebola hemorrhagic fever is a serious and often fatal disease unless promptly treated. Five species of the virus exist and the recent outbreak in 2014 in West Africa was caused by the Zaire species.

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The infection is transmitted from one person to another by close skin contact, body fluid and secretions and sexual contact.

It is characterized by the onset of

• Fever with sore throat, muscle pain and fatigue
• Diarrhea and vomiting accompanied by a rash are also reported
• Impaired kidney and liver function 
• External as well as internal hemorrhage
• Low platelet and white cell counts and elevated liver enzymes

There is no specific treatment or vaccine and treatment is mainly supportive with oral and intravenous fluids and management of the symptoms.

Education and creating awareness of mode of spread in both the community as well as the healthcare setting is crucial to reducing human to human transmission.

Scope of Future Research

Further research is necessary to delineate the role of lungs in the pathogenesis of the disease and to determine if they are also involved in disease transmission. It might also aid development of newer drug treatment and vaccines for this deadly disease.

Reference:

1. Biava M, Caglioti C, Bordi L, Castilletti C, Colavita F, Quartu S, et al. Detection of Viral RNA in Tissues following Plasma Clearance from an Ebola Virus Infected Patient. PLoS Pathogen (2017) DOI: 10.1371/journal.ppat.1006065
2. Ebola virus disease - (http://www.who.int/mediacentre/factsheets/fs103/en/)

Source-Medindia