The Zika virus is transmitted to people in most cases by means of being bitten by the Aedes mosquito species, but there is evidence that it can also be transmitted perinatal, in utero, sexually and from asymptomatic blood donors or transfusion during an outbreak.
The Aedes mosquito lives and breeds in standing fresh water, typically found in the poorer sections or rural areas of countries where domestic water is often found in open container type vessels due to the lack of adequate water systems in the individual homes. It is for this reason the Zika virus has caused such major outbreaks in South American countries.
At this time the Centers for Disease Control (CDC) and the World Health Organization (WHO) does not know enough about the Zika virus to make any “definitive statements” about what illnesses the virus causes, but studies and investigations are under way and recommendations are being based on what these organizations have seen thus far.
Is The Zika Virus Sexually Transmitted?
As stated before in this article there is not enough studies on the Zika virus to know for certain yet, but there is very strong evidence to suggest it is sexually transmitted. In fact on February 3, 2016 the Centers for Disease Control and Prevention announced that a patient in Dallas County, Texas contracted the virus after having sex with a person who had returned from a country where the Zika virus was circulating (meaning the virus outbreak was currently spreading).
According to the CDC there is another case they are relying on to come to the conclusion that the Zika virus is spread sexually. In Colorado in 2008, two scientists had returned home after spending months in Senegal where they had been bitten by the Aedes mosquito. One of the scientist’s wives became infected with the Zika virus, despite the fact that his wife had not traveled outside of the United States in numerous years. The couple noticed bloody semen a few days prior to the wife getting sick and subsequently testing positive for the virus. In the Texas and Colorado cases the infections occurred during the winter months when it is too cold for the Aedes mosquito to be out spreading the Zika virus. Therefore, making those two particular cases impossible to have been spread by the mosquito, hence the conclusion it was contracted through human sexual intercourse.
But there is additional information too, in 2013 in the midst of a Zika outbreak there was a man in Tahiti who had not had Zika symptoms for more than two weeks, yet the virus was “isolated” from his bloody semen. The virus was not present in his blood, but it was found in his urine and his semen contained live virus capable of being transmitted to others.
Also researchers in Japan studied boars infected with a virus of the same family as Zika and again were able to isolate virus from the urine and semen from the boars and then artificially inseminate a female boar which in turn infected the female with the virus. And so it is because of this cumulative information that the CDC was prompted to come out with their announcement today that the Zika virus can be sexually transmitted.
What Diseases are Associated with the Zika Virus?
There are no conclusive studies out yet, but the significant increase in birth defects in newborn babies in Brazil has led a surge in research in this area and the basis for the warnings for pregnant women; in particular microcephaly a drastic birth defect in the brain of newborn babies and an increase in Guillain-Barre Syndrome, as well as other suspected associated birth defects.
What are the Symptoms of the Zika Virus and Where Does It Show Up?
In adults the Zika virus often has no noticeable or apparent symptoms, or very mild ones which don’t last long such as; slight fever, joint pain, rash and conjunctivitis (pink eye). However, as mentioned above men may have bloody semen even after the Zika symptoms have disappeared if they showed up at all. According to the CDC only one in five people will present Zika symptoms. http://www.cdc.gov/zika/hc-providers/clinicalevaluation.html
Research conducted on a French Polynesia outbreak, the largest to date, has led to the most information on how and where the Zika virus shows up. In one study the virus showed up in the saliva of patients just after the onset of Zika symptoms. While another study in New Caledonia found that the virus could be detected in the urine of patients as many as ten days after their first symptoms appeared and one week after it was undetectable in their blood.
And in a third study two babies that tested positive for the Zika virus after just a few days of their birth led researchers to conclude that the infants contracted it from their mother’s bodily fluids during the birth process or breast milk. Researchers do not know how the virus remains viable in a pregnant woman’s bodily fluids or breast milk, but suspect it “may hide in white blood cells,” says Dr. Robert Tesh, a professor at the University of Texas Medical Branch who studies emerging infectious diseases. http://www.npr.org/sections/health-shots/2016/02/03/465339603/what-we-know-so-far-about-sexual-transmission-of-zika-virus
How Is the Zika Virus Diagnosed?
An initial diagnosis may be based on a patient’s symptoms, places and dates of travel, as well as activities. Based on the patient meeting the Zika virus criteria a confirmatory diagnosis typically is done through laboratory testing of serum or plasma (blood tests).
What Countries Have Zika Virus Travel Warnings?
Below you will find Zika Travel Notices directly from the Centers for Disease Control:
Zika Travel Notices
- Zika Virus in Cape Verde
- Zika Virus in the Caribbean
Currently includes: Barbados; Curaçao; Dominican Republic; Guadeloupe; Haiti; Jamaica; Martinique; the Commonwealth of Puerto Rico, a U.S. territory; Saint Martin; U.S. Virgin Islands
- Zika Virus in Central America
Currently includes: Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Panama
- Zika Virus in Mexico
- Zika Virus in the Pacific Islands
Currently includes: American Samoa, Samoa, Tonga
- Zika Virus in South America
Currently includes: Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Suriname, Venezuela
There have been cases of the Zika virus in the United States but these cases have been directly linked to people who traveled to countries with Zika outbreaks or had sex with someone who has. There is no Aedes mosquito bite driven cases in the U.S. at this time.