As said earlier, the virus is primarily transmitted via the bite of an infected mosquito of the Aedes species. It can be found anywhere in the world, but the species are more dominant in the tropical and subtropical regions of the world. Mosquito bites often increase during spring and summer when these insects are actively breeding.
The mosquito can become a carrier of the virus if it bites an infected person. In the same vein, when the mosquito infected by the virus bites an individual, the virus moves into the bloodstream. In pregnancy, the virus can get into the fetus. Other causes of viral transmission include sexual intercourse and blood transfusion.
Apart from the causes, many factors can put anyone at risk. The risk factors can be modifiable or non-modifiable. This means some can be changed while others may not be altered and put you at higher risk. The factors include:
- Living or traveling to countries where the Zika virus is circulating or where outbreaks have been reported: this is a significant risk factor ever. Living in or traveling to regions of the world in the tropics or subtropics without adequate protection is a big risk factor.
These regions are said to be high-risk. Examples are islands near West Africa and the Pacific region, some countries in Central, South, and North America. Although because this mosquito species can be found all over the world, there is a chance that spread to new regions will continue.
Reports have it that the mosquitoes harboring the virus are found in some regions of the United States. However, many cases of the infection reported were in travelers who returned to the United States from the endemic areas. Evidence of local transmission has also been established in some parts of the U.S.
- Infected blood for blood transfusion: routine blood screening should also include the screening for the Zika virus. If an individual gets transfused with infected blood, that person may not only come down with the infection but will also propagate the spread of the disease when bitten by the mosquito.
- Unprotected sex and multiple sexual partners: sexual intercourse is another major channel for the transmission of the virus. Reports have shown that there are more cases of transmission through sex than ever thought of.
Having unprotected sex with a male or female partner in an endemic region or who traveled to an endemic area puts one at risk. Foy et al. first suggested Zika virus transmission by sexual intercourse.
The study, which was published in 2011, described the case of a male patient who got infected in South-eastern Senegal in 2008 and infected the wife via sex upon return to the United States of America. Since then and until the year 2016, sexual transmission of the virus has been reported in 11 countries, including the United States of America. The transmission was limited to vaginal transmission only. However, in February 2016, the CDC in the United States announced the first case of transmission via anal sex to be documented.
Shortly after that, in April, a case was reported that raised the suspicion of the virus through oral sex. The case was said to have had sexual contact with a partner with symptoms of Zika virus infection.
Transmission through oral sex was suspected because the sexual activity involved vaginal penetration with no condom and no ejaculation, and oral sex with ejaculation. The cases reported up until June 2016 were only from symptomatic males when the transmission was reported between asymptomatic cases.
The Center for Disease Control and Prevention (CDC) advises that if sex partners or a couple travel to an area with the Zika virus circulating, there are two things involved.
For the male, he should use a condom during sex or altogether avoid sex for three months. For female sex partners, on the other hand, it is advised that condoms or sex is avoided for at least two months.
The CDC suggests that abstinence from all forms of sexual activity in pregnancy or if need be for sex, use a condom.