The Impact of the Zika Virus on the State of Illinois

The Prairie Research Institute has drafted the following memorandum on the impact of the Zika virus on the State of Illinois:

"Zika is Cause for Concern in Illinois

The Zika virus is not currently transmitted by mosqitoes in Illinois or in the nation, yet Zika can be sexually transmitted from citizens who have had the virus who have traveled to affected areas. For this reason, it’s important to know why Zika is a critical issue now and how citizens can protect their families.

What is the Zika virus?

The Zika virus was first identified in 1943 from a Rhesus monkey in the Zika Forrest in NE Uganda. This type of virus originates in a species that is a natural host; in this case the hosts are monkeys and orangutans. These species do not get sick from the virus, so the virus is continually present in particular primate populations at low levels. Mosquitoes transmit the virus within the population, but also to other species, including humans.

What species of mosquitoes transmit the virus?

Several Aedes species of mosquitoes have been identified that transmit Zika in various areas, such as Africa, French Polynesia, and Brazil. The species implicated in a Brazilian outbreak of the illness does occur in the southern United States, but usually only as far north as central Kentucky.

Related species of mosquito are found in Illinois and elsewhere in the U.S.; thus research projects are needed to evaluate the ability of certain mosquito species to transmit Zika.

Why is Zika a health issue?

Symptoms of the infection typically include a rash, fever, and pink eye, and thus are not particularly dangerous. While thousands of Zika-like symptoms were reported from an outbreak in Brazil in 2015, only 2 deaths were linked to Zika, and other causes were involved. Only a small percentage of people who are exposed to the virus show any symptoms.

However, pediatricians in Brazil began to suspect a correlation between a history of Zika infection in mothers who had given birth to infants with microcephaly, in which an infant’s head and brain are underdeveloped. How Zika causes microcephaly has not been shown, and since many factors can cause microcephaly in infants, including poor nutrition, drinking, and smoking the link has not technically been proven, but the correlation between Zika infection and a severe form of microcephaly is so strong the Centers for Disease Control and Prevention has recently concluded Zika is likely the cause. Zika infection during the first trimester of pregnancy carries the greatest risk for microcephaly, though a few third trimester cases have been identified.

Evidence is now growing about a link between cases of Guillain-Barre syndrome and the Zika infection in areas where Zika outbreaks have occurred. Guillain-Barre syndrome is a disorder in which the immune system attacks the nerves and causes paralysis.

In February, the World Health Organization declared the Zika virus a global health emergency. Also that month, the Centers for Disease Control and Prevention confirmed the first case of Zika transmitted by sexual contact, which happened in Texas.

What is the situation in Illinois?

As of April 2016, all investigated cases of Zika in Illinois and the continental U.S. have been found to be travel-related, with no mosquito transmission suspected, though local transmission of Zika by mosquitoes is routinely being reported in Puerto Rico. Still, it is important to understand that travel-related infections can be sexually transmitted to partners. Women of child-bearing years who have the potential to become pregnant should avoid traveling to areas where Zika infections have been reported, or women should take extreme measures to avoid pregnancy and to avoid exposure to mosquito bites.

What needs to be done about this issue?

The Prairie Research Institute (PRI) at the University of Illinois is addressing this issue by convening a group of scientists who have expertise in the area of mosquito and other vector control. According to these experts, if local transmission of Zika is established in the U.S., Florida, Alabama, and Louisiana are the most vulnerable states due to their near sub-tropical climate and the presence of the Aedes aegypti species of mosquito, the same species that transmitted the virus in the Brazilian outbreak.

PRI scientists recommend the following if local transmission occurs in Illinois and the nation:

- Increased vigilance and more aggressive control measures are needed, particularly for various mosquito species implicated or closely related to those in Zika outbreaks; the funding for Mosquito Abatement Districts and local government mosquito control programs needs to be restored and potentially increased.

- Increased enforcement of used tire storage needs to be implemented; 

- Research should be conducted on the potential ability of the Zika virus to survive overwintering;

- Assessments should be taken on whether rodents or small mammals might be serving as hosts for the virus in tropical areas were primates do not occur; 

-Genetically engineered mosquito gut bacteria capable of intercepting and neutralizing viruses should be developed. PRI is currently assessing the potential for developing this new technology."

Contact for more information: Brian Anderson, Prairie Research Institute; (217) 333-5111