A herpes-type virus, later named Epstein-Barr virus (EBV), has been frequently detected in cell lines derived from Burkitt's lymphomas, leukemic tissues, and buffy coats of patients and healthy donors. This virus is associated with infectious mononucleosis (IM) and is believed to be a new member of the herpes group. EBV is transmitted to cultured human cells of the hematopoietic system and can be detected by indirect immunofluorescence tests. Serological surveys indicate that EBV infections are common worldwide, with a prevalence similar to other common viruses in children. Although no direct link between EBV and other diseases has been established, the virus is suspected to be the cause of IM. The study found that all acute stage sera from IM patients contained high levels of anti-EBV antibodies, suggesting a strong association. In a prospective study, patients with IM showed a clear progression of EBV infection, with antibodies persisting for many years. The virus is also found in patients with Burkitt's lymphoma and carcinomas of the postnasal space, suggesting a possible role in these diseases. While EBV's oncogenic potential remains unclear, the virus is known to persist in cells and may contribute to the development of certain cancers. The study concludes that EBV is likely the cause of IM and may also be involved in the etiology of Burkitt's lymphoma. The findings support the idea that EBV is a significant pathogen in human health, with wide-ranging implications for public health and medical research.A herpes-type virus, later named Epstein-Barr virus (EBV), has been frequently detected in cell lines derived from Burkitt's lymphomas, leukemic tissues, and buffy coats of patients and healthy donors. This virus is associated with infectious mononucleosis (IM) and is believed to be a new member of the herpes group. EBV is transmitted to cultured human cells of the hematopoietic system and can be detected by indirect immunofluorescence tests. Serological surveys indicate that EBV infections are common worldwide, with a prevalence similar to other common viruses in children. Although no direct link between EBV and other diseases has been established, the virus is suspected to be the cause of IM. The study found that all acute stage sera from IM patients contained high levels of anti-EBV antibodies, suggesting a strong association. In a prospective study, patients with IM showed a clear progression of EBV infection, with antibodies persisting for many years. The virus is also found in patients with Burkitt's lymphoma and carcinomas of the postnasal space, suggesting a possible role in these diseases. While EBV's oncogenic potential remains unclear, the virus is known to persist in cells and may contribute to the development of certain cancers. The study concludes that EBV is likely the cause of IM and may also be involved in the etiology of Burkitt's lymphoma. The findings support the idea that EBV is a significant pathogen in human health, with wide-ranging implications for public health and medical research.