The Zika virus has recently come into prominence and is causing
alarm in concerned circle. The virus is
spreading rapidly - it is spreading so fast that it is expected to infect nearly four million people in the Americas in the
next 12 months.
The World Health Organisation is set to convene an
international health regulations emergency committee on Zika virus on February
1 in Geneva to
ascertain whether the outbreak constitutes a public health emergency of
international concern.
World Health Organization
Director-General Margaret Chan said, "The level of alarm is extremely
high," which is why they are considering declaring a public emergency.
Map showing spread of the Zika virus
Why is the spread of the Zika virus being taken so
seriously? What disease does it cause?
The chief apprehension with
the Zika virus is that it has
been associated with neurological problems in babies born to mothers infected
with the virus during pregnancy.
The virus can pass through the placenta and amniotic fluid
in infected pregnant women and may
trigger brain damage with failure in development of the brain. Because the brain does
not grow at a normal pace, the skull doesn’t, either. This causes the brain as well
as the skull to be smaller in size – this abnormality is known as microcephaly (abnormally small head) in
new-born babies. This is a serious condition which can cause severe abnormalities in babies.
The affected babies may have mental retardation, delayed
motor and speech functions, seizures, facial distortions, dwarfism,
hyperactivity and spasticity and a difficulty in balance and coordination of
the body.
Women who are infected in the first trimester is believed to
be at an increased risk for having a child with microcephaly. Scientists do not yet have sufficient knowledge of effects
of the infection in the second and third
trimester.
The link between Zika infection and microcephaly has not been
conclusively proved but the association is strong enough to cause health
officials to caution pregnant women to avoid travelling to countries at risk of
Zika virus transmission. Women in high risk areas have also been advised not to
get pregnant for at least 2 years.
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| Microcephaly |
The main symptoms of GBS are muscle weakness, tingling and numbness of the body which starts at the
fingers and toes, difficulty in walking steadily, low back pain and difficulty
in moving the eyes or face, talking chewing and swallowing. The condition may
spread rapidly throughout the body with muscle weakness leading to paralysis.
If the respiratory muscles are affected by GBS, it is an acute emergency and may lead to death.
Spread of the Zika virus
The virus is spread by bites from an infected Aedes mosquito,
especially A. aegypti. The Aedes mosquito is a daytime
mosquito, characterized by whitish bands on its legs and markings on its body. It is more common in urban areas and breeds in
stagnant water in containers in and
around the house.
The Aedes Mosquito
The female mosquito
needs human blood to get nutrients for the developing eggs and transmits the
virus through its saliva at the time of biting.
The Aedes mosquito also transmits other diseases like
malaria, dengue and chikungunya.
Incubation period
The first symptoms begin 2-7 days after the bite of an infected
mosquito. The Zika virus passes very quickly through the bloodstream and in
most cases, the virus would clear from the bloodstream within about a week.
Symptoms of Zika
-Mild and only one in five humans bitten by the mosquito
will develop the disease. Most people may be unaware that they are infected. Those people then become carriers during the time
they have symptoms.
- Common symptoms
are fever, headache, rash and possible pink
eye (conjunctivitis). Other symptoms are muscle pain and headache. A feeling of
general ill health may persist for weeks.
- Symptoms may last for several days to a week.
- Complications or death is
rare.
Diagnosis of Zika
In most cases, diagnosis of Zika is based on the clinical
symptoms and the outbreak of the disease
in the locality.
Virological (PCR)
tests may be positive in the first 3-5 days of infection when the virus is in
the blood. Serological tests which detect the presence of antibodies to the
virus are useful only after 5 days of the infection when the antibody levels
become detectable in the blood.
No commercial tests are available to diagnose Zika but blood
tests can be done at state laboratories
Treatment of Zika
infection
- There is no specific medicine for Zika. Treatment is
symptomatic to relieve the symptoms and support the patient through the infective phase.
- Medicines like acetaminophen or paracetamol should be
taken to decrease muscle pain and fever. NSAIDS like Ibuprofen and Naproxen
should be avoided since they increase the risk of bleeding from the mucus
membrane.
- Adequate fluids should be taken to avoid dehydration.
- Rest is necessary since the viral infection may cause
fatigue .
- Contraceptives should be used to avoid getting pregnant when there is a known
case of Zika in the locality.
- No vaccines are presently available to prevent Zika
although may become available in about 3 years..
Prevention of Zika
Infection
Zika can be prevented by (a)
not allowing mosquitoes to breed (b) avoiding mosquito bites.
(a) Preventing breeding of mosquitoes
- Outdoor containers in which water can collect(flower pots, bottles etc) should
be emptied out and removed.
- Accumulated
garbage, including piles of leaves or that around waste bins should be cleaned. Restaurants and other
eateries in the locality should be checked for proper garbage disposal.
- Water tanks in the house or outdoor ponds should be covered to prevent mosquitoes from
getting in and laying eggs.
- Screens and mosquitoes nets should be attached to doors
and windows to prevent mosquitoes from entering the house.
- Drains and pipes which can accumulate water should be
cleaned out and covered.
(b) Avoiding mosquito bites.
- Long sleeved shirts and blouses at should be worn at all
times and more specially during the day since the mosquito bites mainly during
the day.
- Mosquito repellants should used at all times.
- Sleeping under
mosquito nets should be encouraged.
Conditions which
have symptoms similar to Zika
Dengue
Chikungunya
Yellow fever
Malaria
Leptospirosis
Rickettsia
Measles
