Zika May Be Linked to Joint Defects, Study Says

     (CN) — There may be a connection between the Zika virus and a brutal birth defect that leads to severe joint deformities, according to a new study published Tuesday.
     The study demonstrates the possible link between the mosquito-borne virus and arthrogryposis, which causes joint deformities at birth, specifically in the legs and arms.
     While microcephaly — a congenital disorder that leads to abnormally small heads — and other fetal brain defects are the primary conditions associated with Zika infection during pregnancy, other potential health problems stemming from the virus may also exist.
     Children suffering from arthrogryposis have limited movement in joins, and sometimes the joints are stuck in a position and cannot bend. The condition is typically not painful, however.
     The condition was not connected to a maternal viral infection before 2015, and was typically linked to fetal akinesia, when a fetus does not move around enough in the womb for various reasons. The condition affects 1 in 3,000 children.
     Following the initial outbreak of Zika in mid-2015, two reports suggested a connection between the virus and arthrogryposis but did not describe the physical deformities in detail.
     In order to analyze the potential connection, a research team in Recife, Brazil — the city at the center of the Zika epidemic — investigated the potential causes of the joint abnormalities.
     The group studied detailed brain and joint images of seven children with arthrogryposis and a diagnosis of congenital infection, likely caused by Zika.
     Each of the children tested negative for five other primary infectious causes of microcephaly, including toxoplasmosis, rubella, cytomegalovirus, syphilis, and HIV.
     The subjects showed signs of brain calcification — a condition that leads to calcium build-up in the brain. The researchers believe the calcification is the result of Zika destroying brain cells and forming lesions where calcium is deposited.
     High-definition scans of the joints and surrounding tissues presented no evidence of joint abnormalities.
     Based on this, the researchers say that the arthrogryposis “did not result from abnormalities of the joints themselves, but was likely to be of neurogenic origin” — a process involving motor neurones, the cells that control the relaxation or contraction of muscles. The neurogenic damage leads to fixed postures in the womb and corresponding deformities.
     While definitive conclusions cannot be drawn since the researchers conducted an observational study, the team suggests that the condition might be related to how motor neurons transport signals to the baby’s muscles, or to problems with arteries and veins.

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