T-2 toxin can cause lesions in hematopoietic, lymphoid, gastrointestinal, and cartilage tissues, especially in physeal cartilage. Fulvic acid present in drinking water damages cartilage cells. Selenium supplementation in selenium deficient areas has been shown to prevent this disease. However, selenium supplementation in some areas showed no significant effect, meaning that deficiency of selenium may not be the dominant cause in KBD. Recently a significant association between SNP rs6910140 of COL9A1 and Kashin–Beck disease was discovered genetically, suggesting a role of COL9A1 in the development of Kashin–Beck disease. Cause
The cause of KBD remains controversial. Studies of the pathogenesis and risk factors of KBD have proposed selenium deficiency, inorganic (e.g. manganese, phosphate) and organic matter (humic and fulvic acids) in drinking water, and fungi on self-produced storage grain (Alternaria sp., Fusarium sp.) producing trichotecene (T2) mycotoxins. Most authors accept that the cause of KBD is multifactorial, selenium deficiency being the underlying factor that predisposes the target cells (chondrocytes) to oxidative stress from free-radical carriers, such as mycotoxins in storage grain and fulvic acid in drinking water. In Tibet, epidemiological studies carried out in 1995–1996 by MSF and coll. showed that KBD was associated with iodine deficiency and with fungal contamination of barley grains by Alternaria sp., Trichotecium sp., Cladosporium sp. and Drechslera sp. Indications existed as well with respect to the role of organic matters in drinking water.
Cytomegalovirus (CMV) (from cyto- cell via Greek κύτος kútos- container + μέγας mégas big, megalo- + -virus via Latin vīrus poison) is a genus of viruses in the order Herpesvirales, in the family Herpesviridae, in the subfamily Betaherpesvirinae. Humans and other primates serve as natural hosts. The 11 species in this genus include human betaherpesvirus 5 (HCMV, human cytomegalovirus, HHV-5), which is the species that infects humans. Diseases associated with HHV-5 include mononucleosis and pneumonia. In the medical literature, most mentions of CMV without further specification refer implicitly to human CMV. Human CMV is the most studied of all cytomegaloviruses.MX2/MXB was identified as a restriction factor for herpesviruses, which acts at a very early stage of the replication cycle and MX2/MXB restriction of herpesvirus requires GTPase activity. Taxonomy
Within the Herpesviridae, CMV belongs to the Betaherpesvirinae subfamily, which also includes the genera Muromegalovirus and Roseolovirus (human herpesvirus 6 and human betaherpesvirus 7). It is also related to other herpesviruses within the Alphaherpesvirinae subfamily, which includes herpes simplex viruses 1 and 2 and varicella-zoster virus, and the Gammaherpesvirinae subfamily, which includes Epstein–Barr virus and Kaposis sarcoma-associated herpesvirus.Several species of Cytomegalovirus have been identified and classified for different mammals. The most studied is Human cytomegalovirus (HCMV), which is also known as Human betaherpesvirus 5 (HHV-5). Other primate CMV species include Chimpanzee cytomegalovirus (CCMV) that infects chimpanzees and orangutans, and Simian cytomegalovirus (SCCMV) and Rhesus cytomegalovirus (RhCMV) that infect macaques; CCMV is known as both Panine beta herpesvirus 2 (PaHV-2) and Pongine betaherpesvirus 4 (PoHV-4).