MOSQUITO
All mosquitoes need water to complete their life cycle. This water can range in quality from melted snow water to sewage effluent and it can be in any container. The type of water in which the mosquito larvae is found can be an aid to the identification of which species it may be. The adult mosquitoes show a very distinct preference for the types of sources in which to lay their eggs. They lay their eggs in places such as tree holes that periodically hold water, tide water pools in salt marshes, sewage effluent ponds, irrigated pastures, rain water ponds, etc. Each species therefore has unique environmental requirements for the maintenance of its life cycle.
In the bloodsucking species, only the female mosquito
sucks blood. Male mosquitoes do not
bite, but feed on the nectar of flowers. Mosquitoes that do carry important
diseases, neither all species of mosquitoes, nor or all strains of a given
species transmit the same kinds of diseases, nor do they all transmit the
diseases under the same circumstances. Their habits differ. Some species attack
people in houses and residential/public places and others prefer to attack
people walking in forests.
Mosquitoes that bite humans routinely act as vectors for a number of infectious
diseases affecting large number of people every year. Others that do not
routinely bite humans, but are the vectors for animal diseases, may become
disastrous agents for propagation of new diseases when their habitat is
disturbed, for instance by sudden deforestation, expanstion of
industrialization,etc.
As far as their life style is considered, like
other flies, mosquitoes go through four stages in their life cycle: egg,
larva,
pupa, and adult or imago. In most species, adult
females lay their eggs in stagnant water. Some lay eggs near the water's edge;
others attach their eggs to aquatic plants. They lay eggs in dwellings at
darker places of the house. Each species selects the situation of the water
into which it lays its eggs and does so according to its own ecological
adaptations. Such differences are important because certain ecological
preferences keep mosquitoes away from most humans, whereas other preferences
bring them right into houses at night.
FEMALE MOSQUITO
FEMALE MOSQUITO
The eggs hatch to become larvae, which grow until
they are able to change into pupae. The adult mosquito emerges from the mature pupa as it
floats on the water surface or the place it was laid. Bloodsucking mosquitoes,
depending on species, gender, and weather conditions, have potential adult lifespan
ranging from one week to as long as several months.
The mosquito larva has a well-developed head with
mouth brushes used for feeding, a large thorax with no legs, and a segmented abdomen.
Larvae develop through four stages, after which they metamorphose
into pupae.
At the end of each stage, the larvae molt, sheds its skin to allow for further
growth.
Some species of mosquitoes develop
from egg to adult in as little as five days where as a more typical period of
development in tropical conditions would be around even 40 days or more for
most species. The variation of the body size in adult mosquitoes depends on the
density of the larval population and food supply within the breeding water.Mosquitoes act as a vector for many disease-causing viruses and parasites. Infected mosquitoes carry these organisms from person to person without exhibiting symptoms themselves. Mosquito-borne diseases include: Viral diseases, such as Yellow fever, Dengue fever and Chiken-gunya. Dengue fever is the most common cause of fever in travelers returning from the Caribbean, Central America, and South Central Asia. This disease is spread through the bites of infected mosquitoes and cannot be spread person to person. Dendue fever is seen in India also.
With good and timely treatment, less than 1% of
patients die from dengue. Other transmitted viruses are as follows:
- The parasitic disease malaria, carried by mosquitoes of the genus Anopheles
- Lymphatic filariasis (the main cause of elephantiasis)
- West Nile virus is a concern in the United States, but there are no reliable statistics on worldwide cases.
- Tularemia, a bacterial disease caused by Francisella tularensis, is variously transmitted, including by biting flies. Culex and Culiseta, are vectors of tularemia as well as virus infections such as West Nile Virus.
Various species of mosquitoes transmit various types of disease. It is said
that at least two million people annually die of these diseases, and the morbidity
rates are many times higher still.
Methods used to prevent the spread of disease, or to protect individuals in
areas where disease is endemic, include:
Vector
control aimed at mosquito
control or eradication
Disease
prevention, using prophylactic drugs and developing vaccines
There are variety of chemical based repellents in the market sold by
different companies.Though they are not safe public got accustomed to use coils
and liquid repellents as there is no alternate.Tha Public Health Departments have all facilities to control the breeding of Mosquitoes
