SPECIAL_ Lassa Fever-what You Should Know

INTRODUCTION
It was first described in the 1950s, however the
virus causing the disease was not identified until
1969, when it's discovered in two missionary
hospitals in the Lassa town of Borno State, the
virus is a single-stranded RNA. Most of the
people infected (about 80%) usually are not
symptomatic. In severe cases, it can result in
multi-organ damage.
Lassa fever is mainly found in Sierra Leone,
Liberia, Guinea, and Nigeria and is spread by
rats. Other neighbouring countries are also at
risk because the type of rat that spreads the
virus is also found throughout the West African
region.
Because the clinical course of the disease is so
variable, detection of the disease in affected
patients has been difficult. However, when
presence of the disease is confirmed in a
community, prompt isolation of affected patients,
good infection protection and control practices
and rigorous contact tracing can stop outbreaks.
TRANSMISSION
It is, 'zoonotic,' or animal-borne. Lassa fever is
endemic in parts of west Africa which include
the following areas:
Liberia
Guinea
Nigeria
Sierra Leone
Humans usually become infected with Lassa
virus from exposure to urine or faeces of
infected Mastomys rats. Lassa virus may also be
spread between humans through direct contact
with the blood, urine, faeces, or other bodily
secretions of a person infected with Lassa fever.
There is no epidemiological evidence supporting
airborne spread between humans. Person-to-
person transmission occurs in both community
and health-care settings, where the virus may be
spread by contaminated medical equipment,
such as re-used needles. Sexual transmission of
Lassa virus has been reported.
Lassa fever occurs in all age groups and both
sexes. Persons at greatest risk are those living in
rural areas where Mastomys are usually found,
especially in communities with poor sanitation or
crowded living conditions. Health workers are at
risk if caring for Lassa fever patients in the
absence of proper barrier nursing and infection
control practices.
The number of people who experience Lassa
fever each year in west Africa is estimated to be
between 100,000 and 300,000, with around 5,000
people dying from the virus.
SIGNS AND SYMPTOMS
The signs and symptoms of Lassa fever
commonly happen 1-3 weeks after a person has
come into contact with the virus. For most of
those with a Lassa fever virus infection; around
80%, symptoms are mild and under-diagnosed.
Mild symptoms include:
Weakness
Headaches
Slight fever
General malaise
Around 20% of infected people; however, the
disease might progress to more serious
symptoms which include:
Bleeding from the infected person's eyes, gums,
or nose and other parts of the body.
Repeated vomiting.
Respiratory distress.
Pain in the back, chest and abdomen.
Facial swelling and shock.
Neurological issues such as tremors, hearing loss
and encephalitis.An infected person may die
within two weeks of their initial symptoms
because of multi-organ failure.The most common
complication of Lassa fever is deafness.
Different degrees of deafness happen in around
one-third of those who become infected.
Between 15-20% of people who are hospitalized
for Lassa fever die from the illness. Only 1% of
all Lassa virus infections; however, result in the
person's death. The death rates for women in
the third trimester of pregnancy are
exceptionally high.
DIAGNOSIS
The symptoms of Lassa fever are varied and
non-specific, clinical diagnosis is often difficult,
especially early in the course of the disease.
Definitive diagnosis requires testing that is
available only in specialized laboratories.
Laboratory specimens may be hazardous and
must be handled with extreme care. Lassa virus
infections can only be diagnosed definitively in
the laboratory using the following tests:
antibody enzyme-linked immunosorbent assay
(ELISA)
antigen detection tests
reverse transcriptase polymerase chain reaction
(RT-PCR) assay
virus isolation by cell culture.
TREATMENT
'Ribavirin,' is an antiviral drug that has been used
with success in people affected by Lassa fever
in its early stage.
Supportive care that consists of maintenance of:
1. Oxygenation.
2. Blood pressure.
3. Treatment of complicating infections.
4. Appropriate fluid and electrolyte balance.
PREVENTION
Prevention of Lassa fever relies on promoting
good "community hygiene" to discourage rodents
from entering homes. Effective measures include
storing grain and other foodstuffs in rodent-proof
containers, disposing of garbage far from the
home, maintaining clean households and keeping
cats. Because Mastomys are so abundant in
endemic areas, it is not possible to completely
eliminate them from the environment. Family
members should always be careful to avoid
contact with blood and body fluids while caring
for sick persons.
In health-care settings, staff should always apply
standard infection prevention and control
precautions when caring for patients, regardless
of their presumed diagnosis. These include basic
hand hygiene, respiratory hygiene, use of
personal protective equipment (to block splashes
or other contact with infected materials), safe
injection practices and safe burial practices.
Health workers caring for patients with
suspected or confirmed Lassa fever should apply
extra infection control measures to prevent
contact with the patient's blood and body fluids
and contaminated surfaces or materials such as
clothing and bedding. When in close contact
(within 1 metre) of patients with Lassa fever,
health-care workers should wear face protection
(a face shield or a medical mask and goggles), a
clean, non-sterile long-sleeved gown, and gloves
(sterile gloves for some procedures).
Laboratory workers are also at risk. Samples
taken from humans and animals for investigation
of Lassa virus infection should be handled by
trained staff and processed in suitably equipped
laboratories.
On rare occasions, travellers from areas where
Lassa fever is endemic export the disease to
other countries. Although malaria, typhoid fever,
and many other tropical infections are much
more common, the diagnosis of Lassa fever
should be considered in febrile patients returning
from West Africa, especially if they have had
exposures in rural areas or hospitals in countries
where Lassa fever is known to be endemic.
Health-care workers seeing a patient suspected
to have Lassa fever should immediately contact
local and national experts for advice and to
arrange for laboratory testing.