Ebola virus disease (EVD), formerly known as Ebola
hemorrhagic fever, is a severe, often fatal illness
in humans.EVD outbreaks have a case fatality rate of
up to 90%.EVD outbreaks occur primarily in remote
villages in Central and West Africa, near tropical
rainforests. The virus is transmitted to people from
wild animals and spreads in the human population
through human-to-human transmission. Fruit bats of
the Pteropodidae family are considered to be the
natural host of the Ebola virus.
Ebola first appeared in 1976 in two simultaneous
outbreaks, in Nzara, Sudan, and in Yambuku,
Democratic Republic of Congo. The latter was in a
village situated near the Ebola River, from which
the disease takes its name. Although non-human
primates have been a source of infection for humans,
they are not thought to be the reservoir but rather
an accidental host like human beings.
Ebola is introduced into the human population
through close contact with the blood, secretions,
organs or other bodily fluids of infected animals.
In Africa, infection has been noticed among those
handling infected chimpanzees, gorillas, fruit bats,
monkeys, forest antelope found ill or dead or in the
rainforest. Ebola then spreads in the community
through human-to-human transmission, with infection
resulting from direct contact (through broken skin
or mucous membranes) with the blood, secretions,
organs or other bodily fluids of infected people,
and indirect contact with environments contaminated
with such fluids. Men who have recovered from the
disease can still transmit the virus through their
semen for up to 7 weeks after recovery from illness.
Health-care workers have frequently been infected
while treating patients with suspected or confirmed
EVD when infection control precautions are not
Signs and symptoms
EVD is a severe acute viral illness often
characterized by the sudden onset of fever, intense
weakness, muscle pain, headache and sore throat.
This is followed by vomiting, diarrhoea, rash,
impaired kidney and liver function, and in some
cases, both internal and external bleeding. The
incubation period, that is, the time interval from
infection with the virus to onset of symptoms, is 2
to 21 days.
Before a patient is diagnosed as infected with EVD,
one should rule out malaria, typhoid fever,
shigellosis, cholera, leptospirosis, plague,
rickettsiosis, meningitis, hepatitis and other viral
hemorrhagic fevers like dengue, yellow fever and
kyasanur forest disease etc.
Vaccine and treatment
There is no specific treatment nor is any licensed
vaccine for EVD available. Several vaccines are
being tested, but none are available for clinical
use. Severely ill patients require intensive
supportive care. Patients are frequently dehydrated
and require oral rehydration with solutions
containing electrolytes or intravenous fluids.
Prevention and control
No animal vaccine against this is available. Routine
cleaning and disinfection of pig or monkey farms
(with sodium hypochlorite or other detergents)
should be effective in inactivating the virus.
If an outbreak is suspected, the premises should be
quarantined immediately. Culling of infected
animals, with close supervision of burial or
incineration of carcasses, may be necessary to
reduce the risk of animal-to-human transmission.
Restricting or banning the movement of animals from
infected farms to other areas can reduce the spread
of the disease.
As this viral outbreak in pigs and monkeys have
preceded human infections, the establishment of an
active animal health surveillance system to detect
new cases is essential in providing early warning
for veterinary and human public health authorities.
In the absence of effective treatment and a human
vaccine, raising awareness of the risk factors for
Ebola infection and the protective measures
individuals can take is the only way to reduce human
infection and death.
India and EBOLA
There is a risk the deadly virus could be imported
into the country if the large population of Indians
working in the four affected West African nations
returns. There are nearly 45,000 Indian nationals
living and working in Guinea, Liberia, Sierra Leone
and Nigeria - where an outbreak of the disease has
killed 932 people. While the risk of Ebola virus
cases in India is low, preparedness measures are in
place to deal with any case of the virus imported to
India. Government has advised against all
non-essential travel to the four countries, and
authorities will screen travelers who originate from
or transit through affected nations, and track them
after their arrival in India.
The government will also set up facilities at
airports and ports to manage travelers showing
symptoms of the disease. State authorities have been
instructed to designate hospitals with isolation
wards for response to possible cases and to stock
personal protective equipment.
* Dr. H. R. Keshavamurthy is Director (M&C) in PIB
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