As of this month, the WHO stated that Zika is likely a cause of microcephaly in infants and Guillain-Barré syndrome in some aults. Zika has also been linked to spontaneous abortion and stillbirth. Most cases of Zika in adults are asymptomatic, but 1 in 5 individuals experience a rash and fever. Zika is most commonly spread by the Aedes aegypti mosquito and there is some evidence it may be sexually transmitted.
This new mouse model of Zika infection is one of the first to be established since 1976. Previous models were not clinically relevant because they required the virus to be injected directly into the brain to establish infection. In the new model, mice can be infected through the skin, mimicking infection via a mosquito bite.
Because Zika does not normally infect mice, the researchers had to engineer immune-deficient mice that would be susceptible to the virus. These immune-deficient mice lacked the interferon receptor gene Ifnar1.
The researchers then infected mice with various strains of Zika. The immune-deficient mice died within 10 days, regardless of the strain used. As in humans, the virus accumulated in the brains and spinal cords of the mice. Curiously, they also found virus in the testes of mice, lending support to the idea that Zika can be sexually transmitted.
Wild type mice survived, unless they were infected as newborns; human infants are also susceptible to Zika, but adults are usually not affected. According to study author Michael Diamond, “it appears that pregnant women infected with Zika can pass the virus to babies in utero and that newborns also may be susceptible to infection … other than in infants, we don't really see severe disease in most people with Zika, except for a small fraction who develop Guillian-Barré”.
Source: Cell Host & Microbe, Science Daily, Wikipedia, WHO