types of viruses

A virus is a miniscule pocket of protein that contains genetic material. If you placed a virus next to a bacterium, the virus would be dwarfed. For example, the polio virus is around 50 times smaller than a Streptococci bacterium, which itself is only 0.003mm long. Viruses can be described as either RNA or DNA viruses, according to which type of nucleic acid forms their core. 

The four main types of virus include:

Icosahedral – the outer shell (capsid) is made from 20 flat sides, which gives a spherical shape. Most viruses are icosahedral.

Helical – the capsid is shaped like a rod.

Enveloped – the capsid is encased in a baggy membrane, which can change shape but often appears spherical.

Complex – the genetic material is coated, but without a capsid.

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(Useful for UPSC General Studies, APPSC Group 1 Group 2 , Mains Material, Paper 1, Paper 4 Section 1 Section 2 Section 3, ROLE AND IMPACT OF SCIENCE AND TECHNOLOGY IN THE DEVELOPMENT OF INDIA, GENERAL AWARENESS WITH THE MODERN TRENDS IN LIFE SCIENCES, DEVELOPMENT & ENVIRONMENT PROBLEMS) 

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Diseases caused by mosquitoes

Mosquitoes can carry many types of diseases that are caused by bacteria, parasites or viruses. These diseases include:

Malaria - Malaria is caused by a parasite that is transmitted by an Anopheles mosquito. The parasite grows in your bloodstream and can produce symptoms that develop anywhere from six to eight days to several months after infection.The symptoms include fever, chills, headaches, muscle aches and general malaise (similar to flu symptoms). Malaria is a severe disease that can be fatal, but can be treated with antimalarial drugs. Malaria is prevalent in tropical or sub-tropical climates.

Yellow Fever - Yellow fever no longer occurs in the United States or Europe, but it is prevalent in Africa and parts of South America. It is transmitted by the Aedes aegypti mosquito. Yellow fever produces symptoms similar to malaria, but also includes nausea, vomiting and jaundice. Like malaria, yellow fever can be fatal. There is no treatment for the disease itself, only the symptoms. Yellow fever can be controlled by vaccination and mosquito control.

Encephalitis - Encephalitis is caused by viruses that are transmitted by mosquitoes ­such as the Aedes mosquitoes or Culiseta mosquitoes. The symptoms of encephalitis include high fever, stiff neck, headache, confusion and laziness/sleepiness. There are several types of encephalitis that can be transmitted by mosquitoes, including St. Louis, Western equine, Eastern equine, La Crosse and West Nile. West Nile encephalitis is on the rise in the eastern United States, which has raised concerns about mosquito control .

Dengue Fever - Dengue fever is transmitted by the Asian tiger mosquito, which is native to East Asia and was found in the United States in 1985. It is also transmitted by Aedes aegypti in the tropics. Dengue fever is caused by a virus that produces a range of illnesses, from viral flu to hemorrhagic fever. It is especially dangerous for children.

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(Useful for UPSC General Studies, APPSC Group 1 Group 2 , Mains Material, Paper 1, Paper 4 Section 1 Section 2 Section 3, ROLE AND IMPACT OF SCIENCE AND TECHNOLOGY IN THE DEVELOPMENT OF INDIA, GENERAL AWARENESS WITH THE MODERN TRENDS IN LIFE SCIENCES, DEVELOPMENT & ENVIRONMENT PROBLEMS) 

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Life Cycle of Mosquito

1) Egg:
Different species of mosquitos lay their eggs differently. For example: Culiseta species lay their eggs stuck together in rafts of up to 200 while Ades lay their eggs singly. Most of the eggs hatch within 48 hours and water is one of the most essential requirement for their survival.

2) Larva:
Eggs hatch into larvae which lives in the water but comes up to the surface of water for breathing. It grows further by shedding their skin for four times. They grow and become large when they shed their skin. They have siphon tubes which is used for the purpose of breathing and are hung upside down on the surface of water. They feed on the organic matter and microorganisms present in the water.

3) Pupa:
The larva on shedding their skin for the fourth time gets converted into pupa. This stage is often referred to as the resting and the non feeding stage of development. They are mobile and responds to certain changes in the environment and posses a tail which helps them to move to a protective area.

4) Adult:
The complete development of the pupa leads to the splitting of the skin of the pupa resulting in the formation of an adult mosquito. This stays on water for a short period of time hardening its body parts. Once it is completely dry and strong enough, it emerges out of water beginning a new life cycle.

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(Useful for UPSC General Studies, APPSC Group 1 Group 2 , Mains Material, Paper 1, Paper 4 Section 1 Section 2 Section 3, ROLE AND IMPACT OF SCIENCE AND TECHNOLOGY IN THE DEVELOPMENT OF INDIA, GENERAL AWARENESS WITH THE MODERN TRENDS IN LIFE SCIENCES, DEVELOPMENT & ENVIRONMENT PROBLEMS) 

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