We hypothesized that the stress of cardiac surgery and cardiopulmonary bypass can cause reactivation of a latent CMV infection and that reactivation might be more prevalent in patients with complicated post-operative course. The study aims are:

• To study whether cardiac surgery is a trigger for latent CMV reactivation and to compare reactivation rate between sub groups of patient with complicated post-operative course and non complicated post operative course.
• To study the relationship between expression IL28 SNP rs12979860 and the risk of CMV replication in the non immunocompromised patient undergoing cardiac surgery.

The study population will be screened at the cardiothorathic surgery ward Soroka Medical Center. A member of the study research team will approach individual subjects who are potential candidates (if all inclusion criteria are fulfilled and if there are no exclusion criteria) for participation in the study. The study member will explain the purpose, procedures and intent of the study to each potential participant. Interested patients will be asked to provide written consent prior to performing any study procedure. Each patient will be associated to one group, according to the CMV test results, which will be done at the enrollment.

Study Group - the Study group will comprise of seropositive CMV patients undergoing cardiothorathic surgery and having a complicated postoperative course.

Control Group 1 - the first control group will be comprised of patients who are seropositive CMV undergoing cardiothorathic surgery and having a normal postoperative course.

Control Group 2 - the second control group will include seronegative patients for CMV undergoing cardiothorathic surgery with complicated and uncomplicated post-operative course.

Visit 1 - Screening and enrollment:

After the patient will provide written inform consent data collection will be done by a study member and includes: demographics, clinical and medical information. In addition, vital signs will be taken and blood work: CMV Ab, CMV PCR, CBC, INR, Chemistry and IL28.

Visit 2 - follow up (on the 7th post operative day):

For patients with uncomplicated post operative (post op) course follow up at the cartiothorathic post op clinic one week after discharge. In addition to the routine blood works and medical follow up, a second blood test panel will be drowned including a second CMV PCR for the control group 1. For those patients with complicated post-operative course and prolonged hospitalization a follow up will be done in the cardiothorathic ward and will include medical tracking and blood test for a second CMV PCR for the study group. For control group 2: medical follow up and routine blood works.

Visit 3- follow up 2 (on the 14 th post operative day):

This visit is a follow up for patients still hospitalized post operatively. We will keep medical tracking and draw the last blood test for the 3rd CMV PCR for the study group. For control groups 1 and 2: medical follow up and routine blood works.

Visit 4 - follow up 3 (90 days post op):

Data collection from computerized medical records for all patients.

Inclusion Criteria:

1. Patients admitted for cardiac surgery.
2. Age 18 and above.

Exclusion Criteria:

1. Immunosuppressed patients including: HIV, active cancer, biological chemotherapy, steroid use equivalent to prednisone dosage above 1 mg/Kg a day, post organ transplantation.

The study population will be screened at the cardiothorathic surgery ward Soroka Medical Center.