The CDC announced yesterday that "Scientists at the Centers for Disease Control and Prevention (CDC) have concluded, after careful review of existing evidence, that Zika virus is a cause of microcephaly and other severe fetal brain defects." You can read the press release by clicking here.
The World Health Organization updated their Q&A section today about the Zika Virus and stated that "Based on a growing body of preliminary research, there is scientific consensus that Zika virus is a cause of microcephaly and Guillain-Barré syndrome. While intense efforts continue to reinforce and refine the link between Zika virus and a range of neurological disorders within a rigorous research framework, a stream of recent case report studies as well as a small number of case control and cohort studies, support the conclusion that there exists an association between Zika and microcephaly and Guillain-Barré syndrome."
WHO says that scientists are not ruling out that other factors could be causing the neurological diseases and birth defects, but that more research is needed to make any conclusive statements.
In Haiti, the Zika Virus has not been a large concern. However, travelers are advised to use caution and to protect themselves from mosquito bites (how the disease is transmitted). The travel precuations put out by the CDC are the same as before they made their announcement, "practice enhanced precautions." You can find those travel precautions, specific to Haiti, here.