What is Zika Virus
Zika virus belongs to the flavi virus family. It is closely related to dengue and chikungunya virus. It can be transmitted by the same mosquito that transmits the dengue virus. It was first isolated in Rhesus monkey in the Zika forest of Uganda in 1947, which is how it got its name. Human infections were identified in the 1950s and the disease is endemic in parts of Africa and Asia. An outbreak of the Zika virus infection occurred on Yap Island in the Federated States of Micronesia in 2007
Zika virus is primarily transmitted to humans through bites from Aedes mosquitos. India has a huge reservoir of the Aedes aegypti mosquito which transmits dengue and chikungunya.
Rarely Zika virus can be transmitted via blood transfusion, perinatal transmission and sexual transmission. The incubation period (time from exposure to symptoms) is typically between 2 and 7 days.
Signs and symptoms of Zika Virus
Not all people who are infected have symptoms. About 1 in 5 people develop symptoms.
Zika virus infection is characterized by low grade fever, accompanied by a rash.
Other symptoms include muscle pain, joint pain with possible swelling, headache, pain behind the eyes and conjunctivitis.
Symptoms are often mild, and most people recover without severe complications.
Cases of Guillain-Barre disease have been reported.
Investigations are ongoing to assess the possibility of microcephaly (small brain) in babies due to maternal infection with Zika virus.
Death due to Zika virus is rare.
The virus usually remains in the blood of an infected person for a few days but it can be found longer in some people.
Diagnosis for Zika Virus
RT-PCR of serum sample can be used to diagnose infection in the initial phase. Saliva or urine samples can be tested between days 3-5 for detection of Zika virus.
Serological tests may indicate the presence of anti-Zika virus IgM and IgG antibodies. Serological tests can have cross reactivity with other flavi viruses like dengue, chikungunya etc.. and interpreted with caution.
Treatment for Zika
There is no vaccine or specific antiviral treatment for Zika virus infection. Treatment is to control symptoms:
o Fluids to prevent dehydration
o Paracetamol to relieve fever and pain
o Aspirin and NSAIDS are not advisable
Prevention from Zika Virus
Prevention and control relies on reducing the breeding of mosquitoes and reducing contact between mosquitoes and people.
Basic precautions for protection from mosquito bites should be taken by people traveling to high risk areas. These include use of repellents, wearing light colored, long sleeved shirts and pants and ensuring rooms are fitted with screens to prevent mosquitoes from entering.
• If you have Zika, avoid mosquito bites for the first week of your illness.
o During the first week of infection, Zika virus can be found in the blood and passed from an infected person to another mosquito through mosquito bites.
o An infected mosquito can then spread the virus to other people.
CDC recommends that pregnant women in any trimester should consider postponing travel to an area where Zika virus transmission is ongoing. If a pregnant woman is considering travel to one of these areas, she should talk to her healthcare provider. If she travels, she should strictly follow steps to avoid mosquito bites during the trip.
Specific areas where Zika virus transmission is ongoing are often difficult to determine and are likely to change over time.
Dr. Suneetha Narreddy, MD, ABIM
Consultant, Infectious Diseases