Deadly Viral Diseases spread by Vectors (mosquitos) in Monsoon
Dengue-Dengue fever is a viral fever where the virus is transmitted by mosquitoes, known
as the Aedes Aegypti breed, commonly also called the Tiger mosquito. This mosquito has
black and white stripes and bites in the morning or at dawn.
Patients with dengue fever have high grade fever with severe joint and muscle pain, (hence
the common name is break bone fever), lymph node swelling, headache, and a viral rash.
Sometimes this fever gets complicated and the patient develops what is called the Dengue
haemorrhagic fever (DHF). The patient tends to have a low platelet count and may develop
circulatory collapse and shock. Dengue Haemorrhagic fever is more common in children
under the age of 10 years. Most of the dengue fevers are however self-limiting and the fever
subsides in 5 to 7 days
In Monsoons any viral fever should be investigated for dengue due to its life threatening
complications. A Haemogram or Complete Blood Count (CBC) is advised along with specific
tests like dengue serology for IgG and IgM antibodies. The presence of IgM antibodies
indicates a recent infection and these antibodies become positive normally after the third
day of fever. To diagnose this condition early another test called the NS1 antigen is done,
which becomes positive in the 2 nd day of fever. Dengue PCR is also another investigation that
can be done to diagnose dengue on Day 1 of the illness. However this test is more expensive
and is not required to be done in most cases .If the dengue test is positive regular Platelet
count is important.
Rest and maintaining good hydration is the only treatment and medications such as aspirin
and brufen should not be taken. Simple paracetamol can be given to decrease the fever and
to relieve the pain.
Preventive measures include using a strong insect repellent, wearing full sleeve clothing,
and preventing the breeding of the mosquitoes. Dengue mosquito bites in the day time and
breeds in clean, fresh water so water stagnation should not be allowed.
Chikungunya – Chikungunya is another mosquito borne viral illness. Almost all the people
infected by this will develop the symptoms of this disease. The symptoms start
approximately 4-7 days after the bite by an infected mosquito. The patient complains of
high grade fever with, head ache and severe joint pains known as arthralgia. Most people
start getting better in a week’s time, however in some cases the arthralgia may remain for
many years. This disease is not life threatening but the joint pains are very severe and
disabling. Young children, new-borns and adults over 65 years are at higher risk of
The diagnosis of Chikungunya is done by estimating the IgG and the IgM antibodies against
the Chikungunia virus. The IgM antibodies indicate a current infection and the IgG
antibodies indicate an older infection. These antibodies usually become positive 7-10 days
after the infection and are not useful in diagnosis in early cases. The test of choice for early
diagnosis is Chikungunia PCR which becomes positive from the first day of fever.
Preventing the breeding of mosquitos, wearing long sleeves to prevent mosquito bite and
using mosquito repellents are the best methods of prevention of this disease
Zika – Zika virus disease is another infection spread by the day time biting Aedis mosquitoes
Infection due to this virus is called the Zika Virus disease and the symptoms of this disease is
like a mild form of dengue or any other viral fever. These mild symptoms can be treated
according with Zika virus (ZIKV) is a member of the virus family Flaviviridae. It is spread by
daytime-active Aedes mosquitoes, such as A. aegypti and A. albopictus. Its name comes
from the Zika Forest of Uganda, where the virus was first isolated in 1947. Zika virus is
related to the dengue, yellow fever, Japanese encephalitis, and West Nile viruses. Since the
1950s, it has been known to occur within a narrow equatorial belt from Africa to Asia. From
2007 to 2016, the virus spread eastward, across the Pacific Ocean to the Americas, leading
to the 2015–16 Zika virus epidemic.
In January 2016, the United States Centres for Disease Control and Prevention (CDC) issued
travel guidance on affected countries, including the use of enhanced precautions, and
guidelines for pregnant women including considering postponing travel. Other governments
or health agencies also issued similar travel warnings, while Colombia, the Dominican
Republic, Puerto Rico, Ecuador, El Salvador, and Jamaica advised women to postpone
getting pregnant until more is known about the risks.
However when pregnant women develop this infection it spreads to the baby causing
congenital anomalies like microcephaly, brain malformations and many other congenital
anomalies . The infection with this virus can be detected by doing a Zika virus PCR