Fellow
students, in the past few days there has been an outbreak in some states such
as Taraba, Niger, Nassarawa, Bauchi, Kano and Rivers States, leaving some
people dead and others hospitalised.
Lassa
virus is a member of the arenavirus family. The disease was first described in
the 1950s, and the virus was identified in 1969, when 2 missionary nurses died
from it in the town of Lassa in Nigeria.
Transmission
Lassa virus
is present in rats, which shed the virus in their urine and droppings. These
are common in rural areas of tropical Africa, and often live in or around
homes. Once infected, rodents shed virus throughout their life.
Transmission
of Lassa virus to humans normally occurs through contamination of broken skin
or mucous membranes via direct or indirect contact with infected rodent
excreta, on floors, home surfaces, in food or water. Transmission is also
possible where rodents are caught and consumed as food.
Person to
person transmission occurs through infected bodily fluids, such as blood,
saliva, urine or semen.
This
transmission can happen:
- in the laboratory
- in a healthcare setting
- via sexual or other close contact
Transmission
to close contacts usually only occurs while the patient has symptoms. However,
a patient can excrete virus in urine for between 3 and 9 weeks after the onset
of illness. Patients can transmit the virus via semen for up to 3 months.
Symptoms
Infection
is mild or asymptomatic in 80% of cases, but can cause severe illness and is
fatal in approximately 1 to 3% of patients. The incubation period for disease
is usually between 7 and 10 days, with a maximum of 21 days.
The onset
of illness is insidious, with:
- fever and shivering
- malaise
- headache
- generalised aching
- sore throat
Nausea,
vomiting, diarrhoea or cough can accompany these symptoms.
An
important diagnostic feature is the appearance of patches of white or yellowish
exudate and occasionally small vesicles or shallow ulcers on the tonsils and
pharynx.
As the
illness progresses the body temperature can rise to 41ºC with daily fluctuations
of 2 to 3ºC.
Extreme
lethargy and exhaustion can occur in severe attacks, that is disproportionate
to the level of fever. During the second week of illness symptoms include:
- oedema of the head and neck
- encephalopathy
- pleural effusion
- ascites.
Renal and
circulatory failure may occur, aggravated by vomiting and diarrhoea.
In the
severest cases bleeding into the skin, mucosae and deeper tissues occurs,
usually leading to death.
Symptoms
in children are similar to those in adults, but infant infection can result in
‘swollen baby syndrome’ with oedema, abdominal distension, bleeding and often
death.
Diagnosis
Clinical
diagnosis of Lassa fever is difficult. It can be confused with other infections
such as severe malaria, typhoid fever, and other viral haemorrhagic fevers.
RT-PCR for nucleic acid detection, virus isolation or
antibody detection methods can diagnose Lassa fever.
Treatment
Treatment
with the antiviral drug ribavirin is most effective when started within the
first 6 days of illness, and should be given intravenously for 6 days.
Supportive
care such as fluid replacement, blood transfusion or other appropriate measures
is also essential.
.
Prevention
and control
There is
no licensed vaccine for Lassa fever. In endemic areas, rodent control and
avoiding contact with rodents and their excreta helps prevent infection.
Infection control includes storing food in rat proof containers.
Avoiding
contact with bodily fluids of an infected patient prevents person to person
spread. In healthcare settings these infection control measures include
- special barrier nursing procedures
- VHF isolation precautions to isolate infected patients
- wearing protective clothing for contact with the patient
Once the
patient has recovered they are only infectious via semen and urine. Patients
must avoid sexual intercourse for 3 months.
People
living in endemic areas of West Africa with high populations of rodents are
most at risk of Lassa fever. Imported cases rarely occur elsewhere in the
world. Such cases are almost exclusively in persons who work in endemic areas
in high risk occupations such as medical or other aid workers.
·
Ensure you store foods in rat proof containers
and cook all foods thoroughly before eating.
·
Discourage rodents from entering the house by
blocking all possible entry points.
·
For food manufacturers and handlers, do not
spread food where rats can have access to it.
·
All fluids from an infected person are
extremely dangerous.
·
Lodge presidents should liaise with their
landlords to fumigate their lodges.
·
Students who go for posting are also advised
to be at alert, wear personal protective equipment, observe universal basic
precautions, nurse suspected cases in isolation and report same to your Unit
head immediately.
·
We have already recommended that the CC Hostel
should be fumigated as a matter of urgency.
SIGNED:
COMR. FII TORNUBARI SAMUEL,
CHS-SAG
PRO
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