The researchers studied newborns with joint deformities. They concluded that these were probably due to the Zika virus, and that they would have a neurological cause.
One of the main visible features of Zika virus infection is microcephaly in babies. But this virus could also cause other apparent damage to the joints, in connection with neurological damage. A team of researchers based in Recife (Brazil) publishes in the journal BMJ a study cases in seven children. All of them are born with deformities of the arms and legs, with a diagnosis of congenital infection, probably caused by the Zika virus. The five main known infectious causes of microcephaly (toxoplasmosis, cytomegalovirus, rubella, syphilis and HIV) have been ruled out in these newborns.
Brain and joint abnormalities
Using MRI (magnetic resonance imaging) and tomography techniques, scientists have observed calcification in the brains of infants. They hypothesize that the virus destroys brain cells and forms scar-like lesions, on which calcium settles. In addition to the calcification, the images revealed a malformation in the development of the cortex and a reduction in brain volume.
The researchers also explored the many joint malformations of the small participants, united under the term arthrogryposis. Among them, contractures of the knees or hips, rotations, hyperextensions, or pronounced joint dislocations, or club feet. All these irregularities were analyzed by high definition scanning of the joints and surrounding tissues. Results: The abnormalities do not result from the joints themselves, and there is therefore an external cause for arthrogryposis in infants.
A neurological explanation
Two previous reports published recently suggested an association between congenital viral infection and arthrogryposis. The joint study of the brain and the joints allows researchers to make a connection between the two and to provide a probable explanation for the joint deformities. These could indeed be neurogenic, that is to say they involve motor neurons. These neurons control the contraction and relaxation of muscles, which can lead to fixed postures in utero, and therefore deformities.
The authors of this work propose to add Zika to the diagnosis of congenital infection linked to arthrogryposis, even if they concede that the results of their case study do not make it possible to rule on a cause and effect phenomenon. They recommend orthopedic follow-up for affected children because they could develop musculoskeletal malformations following neurological deterioration.
.