Zika virus

Introduction

Zika virus disease is caused by a virus transmitted by Aedes mosquitoes. It is an emerging mosquito-borne virus that was first identified in Uganda in 1947 in rhesus monkeys. Outbreaks of Zika virus disease have been recorded in Africa, the Americas, Asia and the Pacific.

Symptoms

Symptoms of Zika virus infections are similar to other arbovirus infections such as dengue. Like:-

• Fever
• Skin rashes
• Conjunctivitis
• Muscle and joint pain
• Malaise, and headache

National health authorities in Brazil have reported potential neurological and auto-immune complications of Zika virus disease. Agencies investigating the Zika outbreaks are finding an increasing body of evidence about the link between Zika virus and microcephaly.

Transmission

• Zika virus is transmitted to people through the bite of an infected mosquito from the Aedes genus.
• This is the same mosquito that transmits dengue, chikungunya, and yellow fever.
• Zika virus can migrate between humans through sexual contact
• it can also cross the placenta, affecting an unborn fetus
• An infected mother can pass on the virus to her newborn around the time of birth.
• The vertebrate hosts of the virus are primarily monkeys and humans.

Threat

• Zika virus outbreak in Latin America could be a bigger threat to global health than the Ebola epidemic.
• There is currently no vaccine available for this disease.
• Most virus carriers of Zika virus are symptomless.
• It is a silent infection in a group of highly vulnerable individuals – pregnant women.
• However, Zika virus infection during pregnancy can cause a serious birth defect.

• With at least 80% of those infected showing no symptoms, tracking the disease is extremely difficult.
• Only extreme measures like DDT are likely to contain the Zika threat, which will be environmentally harmful.

Prevention

• Prevention and control rely on reducing mosquitoes through source reduction.
• Reducing contact between mosquitoes and people.
• This can be done by using insect repellent; wearing clothes (preferably light-colored).
• Using physical barriers such as screens, closed doors and windows, and sleeping under mosquito nets.
• Special attention and help should be given to those who may not be able to protect themselves adequately.
• Zika virus is diagnosed through PCR (polymerase chain reaction) and virus isolation from blood samples.

How does virus attack?

• Viruses are tiny organisms that may lead to mild to severe illnesses in humans, animals, and plants.
• Viruses by themselves are not alive. They cannot grow or multiply on their own and need to enter a human or animal cell and take over the cell to help them multiply.
• Viruses lie around our environment all of the time just waiting for a host cell to come along. They can enter us through the nose, mouth or breaks in the skin.
• Once inside, they find a host cell to infect.
• For example, cold and flu viruses will attack cells that line the respiratory or digestive tracts.
• It then begins making copies of the viral genetic instructions and new viral proteins using the virus’s genetic instructions and the cells enzyme machinery.
• The new copies of the viral genetic instructions are packaged inside the new protein coats to make new viruses.

Regardless of the type of host cell, all viruses follow the same basic steps:-

• A virus particle attaches to a host cell.
• The particle releases its genetic instructions into the host cell.
• The injected genetic material recruits the host cell’s enzymes.
• The enzymes make parts for more new virus particles.
• The new particles assemble the parts into new viruses.
• The new particles break free from the host cell Once inside the cell, the viral enzymes take over those enzymes of the host cell.
  

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