A team of researchers from the University of Arizona (UA) has identified U.S.-Mexico borderland region as the area which is at an increased risk of Zika transmission. The researchers have based their conclusion on the history of dengue outbreaks in the region.

UA associate professor Kacey Ernst recently presented a testimony to the Congressional House Committee on Science, Space and Technology. The researcher said that the environmental conditions that persist at the U.S.-Mexico border are suitable for the growth of Aedes aegypti mosquito, which is also responsible for the transmission of Zika virus.

Zika is transmitted by the bite of an infected mosquito. It belongs to a group of viruses called flavivirus. So far, seven travel-related cases of Zika infection have been identified among Arizonians, including one in Pima County.

According to the federal health authorities, once a person gets infected by Zika virus, it is unlikely that he or she will get infected by the virus once again in the future. A person infected by the virus shows symptoms such as fever, conjunctivitis, rash and joint pain. However, the most immediate concern remains the appearance of serious birth defects among infants born to infected mothers.

The risk of Zika outbreak along the U.S.-Mexico border became visible to a group of environmentalists trying to manage the problem in the area. During the surveillance, the research team discovered a foul-smelling pile of waste along the recreational trail in the Tijuana River Regional Park near the Californian border.

The pile of waster is, in fact, a combination of raw sewage, trash, and mud that invaded into San Diego County from Mexico when storms hit the region. The trash that enters the US from Mexico includes a significant amount of tires, which forms a suitable habitat for the Aedes aegypti mosquito to grow.