2. What is ebola virus
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 is however NOT AN AIRBORNE VIRUS
3. EXTREMELY deadly:
About 90% of people
that catch Ebola will
die from it.
It’s one of the
deadliest diseases in
the world, killing in
just a few weeks.
4.
5. To determine geographic
range for Ebola virus:
276 bats in Bangladesh
Five (3.5%) bats were
positive for antibodies
against Ebola Zaire and
Reston viruses
These bats might be a
reservoir for Ebola or
Ebola-like viruses, and
extend the range of
filoviruses to mainland
Asia.
6. Filoviruses are zoonotic pathogens that cause
episodic, lethal, hemorrhagic outbreaks among
humans and nonhuman primates and case-fatality
rates up to 80%
Despite their role in human disease, natural reservoirs of filoviruses
have remained elusive for decades. Reports suggest that bats (Order
Chiroptera) are the primary natural hosts, including Old World
insectivorous bats (genera Rhinolophus and Miniopterus) and
frugivorous bats (familyPteropodidae).
Fruit bats of the genus Rousettus have been implicated as a reservoir
of filoviruses in Africa (4–7) and REBOV in the Philippines (8).
We screened bats of several species from Bangladesh for Ebola virus
infection to determine whether the geographic range of this virus
extends to southern Asia.
7. 50–800 μL of blood were collected from brachial or cephalic veins of each bat, and diluted it
1:4 with phosphate-buffered saline in the field before serum was separated, as described
throat, urine/urogenital, and fecal swab specimens were also collected which were placed in
750 μL of NucliSENS lysis buffer. All samples were collected in cryovials, placed in liquid
nitrogen in the field, and maintained at −80°C until testing.
Fifteen (11%) of 141 R. lescehnaulti, 6 (8%) of 75 Cynopterus spp., and 4 (7%) of 56 M.
lyra bats were potentially positive after initial screening.
8. Conclusion:
Our study provides evidence of Ebola virus infection in wildlife from
mainland Asia and corroborates the observation that filoviruses are
harbored across a much larger geographic range then assumed.
Preferential reactivity to ZEBOV suggests exposure to an Ebola virus that
is distinct from REBOV, the only filovirus currently found in Asia.
We consider the likelihood of cross-reactivity with MARV as low
because there is only a 35% aa identity between nucleoprotein genes of
REBOV/ZEBOV and MARV. However, we cannot rule out co-infection
with multiple filoviruses.
9. Genus Ebolavirus is 1 of 3 members of the Filoviridae family
(filovirus), along with genus Marburgvirus and genus
Cuevavirus. Genus Ebolavirus comprises 5 distinct species:
Bundibugyo ebolavirus (BDBV)
Zaire ebolavirus (EBOV)
Reston ebolavirus (RESTV)
Sudan ebolavirus (SUDV)
Taï Forest ebolavirus (TAFV).
BDBV, EBOV, and SUDV have been associated with large EVD outbreaks in Africa,
whereas RESTV and TAFV have not. The RESTV species, found in Philippines
and the People’s Republic of China, can infect humans, but no illness or death
in humans from this species has been reported to date.
10. Transmission:
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 documented through the handling of infected chimpanzees,
gorillas, fruit bats, monkeys, forest antelope and porcupines 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.
Burial ceremonies in which mourners have direct contact with the body of the deceased
person can also play a role in the transmission of Ebola.
Men who have recovered from the disease can still transmit the virus through their semen for
up to 7 weeks after recovery from illness.
11. 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, diarrhea, rash, impaired kidney and liver function,
and in some cases, both internal and external bleeding. Laboratory findings
include low white blood cell and platelet counts and elevated liver enzymes.
People are infectious as long as their blood and secretions contain the virus.
Ebola virus was isolated from semen 61 days after onset of illness in a man who
was infected in a laboratory.
The incubation period, that is, the time interval from infection with the virus to
onset of symptoms, is 2 to 21 days.
12.
13. Diagnosis
• Other diseases that should be ruled out before a diagnosis of EVD can
be made include: malaria, typhoid fever, shigellosis, cholera,
leptospirosis, plague, rickettsiosis, relapsing fever, meningitis,
hepatitis and other viral hemorrhagic fevers.
Ebola virus infections can be diagnosed definitively in a laboratory through
several types of tests:
antibody-capture enzyme-linked immunosorbent assay (ELISA)
antigen detection tests
serum neutralization test
reverse transcriptase polymerase chain reaction (RT-PCR) assay
electron microscopy
virus isolation by cell culture
14. Vaccine and
treatment
No licensed vaccine for EVD is 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.
No specific treatment is available. New drug therapies are being
evaluated.
15. Natural host of Ebola
virus
In Africa, fruit bats, particularly species of the
genera Hypsignathus monstrosus, Epomops
franqueti and Myonycteris torquata, are
considered possible natural hosts for Ebola
virus. As a result, the geographic distribution
of Ebolaviruses may overlap with the range of
the fruit bats.
16. Ebola virus in
animals
RESTV has caused severe EVD outbreaks in macaque
monkeys (Macaca fascicularis) farmed in Philippines
and detected in monkeys imported into the USA in
1989, 1990 and 1996, and in monkeys imported to
Italy from Philippines in 1992.
Since 2008, RESTV viruses have been detected during
several outbreaks of a deadly disease in pigs in
People’s Republic of China and Philippines.
Asymptomatic infection in pigs has been reported and
experimental inoculations have shown that RESTV
cannot cause disease in pigs.
17.
18. Prevention
and Control
Controlling Reston ebola virus in domestic animals
No animal vaccine against RESTV 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 RESTV outbreaks 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.
19. Reducing the risk of Ebola infection in people
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.
Reducing the risk of wildlife-to-human transmission from contact with infected fruit bats or
monkeys/apes and the consumption of their raw meat.
Animals should be handled with gloves and other appropriate protective clothing. Animal products
(blood and meat) should be thoroughly cooked before consumption.
Reducing the risk of human-to-human transmission in the community arising from direct or close
contact with infected patients, particularly with their bodily fluids.
Close physical contact with Ebola patients should be avoided.
Gloves and appropriate personal protective equipment should be worn when taking care of ill
patients at home.
Regular hand washing is required after visiting patients in hospital, as well as after taking care of
patients at home.
Communities affected by Ebola should inform the population about the nature of the disease and
about outbreak containment measures, including burial of the dead.
People who have died from Ebola should be promptly and safely buried.
