Zika virus is a type of arthropod-borne flavivirus transmitted by mosquitoes. This virus is related to other flaviviruses that most of you might be familiar with--dengue, yellow fever, and West Nile virus. To clarify, this is NOT a new virus. It was first discovered in 1947 isolated from a captive rhesus monkey by scientists conducting routine surveillance for yellow fever in the Zika forest of Uganda, hence, the given name Zika. In 1948, it was then recovered from the mosquito Aedes africanus caught on a tree platform in the same forest. The first human cases were in 1952 detected in Uganda and the United Republic of Tanzania.
Fast forward to 2007 when the first major recognized outbreak occurred in the Yap Islands of Micronesia with more than 70 percent of the population infected were older than three years old; Followed by a larger outbreak in French Polynesia in 2013 to 2014, affecting about 32,000 of its population. Zika virus infection appeared in the Western hemisphere in February 2014 on Chile’s Easter Island with the first infection in Brazil confirmed in May 2015.
Zika virus infection has also been detected in the United States territories of Puerto Rico, the US Virgin Islands, and American Samoa.Currently, there has been no reported outbreak of Zika virus infection in the Philippines, but there has been serologic evidence that this virus have been isolated in the Philippines and other South East Asian countries including Thailand, Vietnam, Malaysia and Indonesia.
Transmission of the virus
There have been several media accounts reporting several modes of transmission of the Zika virus, but the fact remains that the primary transmission to humans occur via the bite of an infected Aedes mosquito. It is true that there are other modes of transmission of the Zika virus. A current “hot topic” is its transmission from an infected pregnant mother to the fetus during pregnancy or around the time of birth. Zika virus is also found to be transmissible via blood products, laboratory exposure and organ or tissue transplantation. Sexual transmission has also been described with detection of Zika virus in semen for 62 days; however, further studies still need to be conducted regarding the viral persistence in semen.
What are the clinical manifestations of an infection?
Once bitten by a mosquito, onset of symptoms is typically 2 to 14 days. The symptoms occur to about 20-25 percent who becomes infected with Zika virus. In adults, majority of clinical manifestations include a low-grade fever, skin rashes, joint pain mostly in the hands and feet, and conjunctivitis. There are also other symptoms reported that are less common to include body pain, headaches, abdominal pain, itching all over body, nausea and diarrhea. In infants and young children, symptoms may include irritability, walking with a limp, difficulty moving or refusing to move arms or legs.
There have been several accounts on intrauterine Zika virus infection in pregnant women associated with microcephaly. Microcephaly is a rare condition where a baby has an abnormally small head due to abnormal brain development of the baby in the womb or during infancy. These cases were mostly observed in Brazil.
There may be an association with Zika virus infection and development of Guillain-Barre syndrome (progressive muscle weakness), however, this has not been definitively established.
How about treatment?
Currently, there is no specific treatment for Zika Virus infection. Management consists of rest and treating the symptoms by drinking a lot of fluids to prevent dehydration and taking acetaminophen to relieve fever and pain.
It all starts with prevention
Currently, there is no vaccine to prevent Zika virus infection.
The best protection from Zika virus is to avoid mosquito bites. If you’re in an area with risk for transmission, protect yourself by wearing long sleeves and long pants; use insect repellant and if you do not have to be outside, stay indoors with window/door screens and mosquito nets. It is also important to empty, clean and cover containers that can hold even small amounts of water such as buckets, flower pots, bottles and jars. Refer to your local and district health departments on what they are doing to help eliminate potential mosquito breeding sites.
If you are pregnant, make sure to follow personal protective measures closely. Consider postponing any upcoming trips to areas where transmission of Zika virus is high.
If someone is infected or exposed to Zika virus, it is very important to abstain from any sexual activity (vaginal, anal, and oral sex) or use condoms as barrier protection.