- 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.
may persist and multiply in the
lungs of patients recovering from the infection, according to a recent research
published in PLOS
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.
‘Persistence of Ebola viral markers in the lung of recovering patient suggest that lungs may have a major role to play in the pathogenesis and human to human transmission.’
In order to determine the possible presence of the Ebola virus in the
, 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 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.
"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
The infection is transmitted from one
person to another by close skin contact, body fluid and secretions and sexual
It is characterized by the
with sore throat, muscle pain and fatigue
and vomiting accompanied by a rash are also reported
kidney and liver function
as well as internal hemorrhage
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.
- 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
- Ebola virus disease - (http://www.who.int/mediacentre/factsheets/fs103/en/)