Larger studies about the link between arthrogryposis and Zika virus infection need to be conducted to better understand the neurological problems that may underlie the condition according to researchers. After the outbreak of microcephaly in Brazil associated with Zika virus, two reports suggested an association, but they did not describe the deformities in detail. But all of the babies had the pattern of abnormalities on their brain scans that would be expected with a congenital Zika syndrome, said lead researcher Dr. Vanessa van der Linden. The virus can cross the placenta from the mother to her unborn child.
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The deformities of arthrogryposis, or crooked joints, are caused by faulty muscles – some too tight or contracted and some too flaccid – that have pulled and held the baby’s growing body in unnatural positions.
For the study, the researchers followed up two previous report linking Zika with arthrogryposis.
“It is becoming increasingly clear that this virus can cause a wide range of other abnormalities, including visual and hearing defects and brain damage in babies with normal-sized heads”, he told Reuters.
Florida is the only US state with known cases of locally acquired Zika infection – 16 so far.
The seven babies with suspected Zika infection that they studied in hospital had been born with hip, knee, ankle, elbow, wrist and/or finger joint problems that fit with a medical diagnosis called arthrogryposis.
The researchers concluded: “Congenital Zika syndrome should be added to the differential diagnosis of congenital infections and arthrogryposis”.
Scientists found the children tested negative for the five other main infectious causes of microcephaly – toxoplasmosis, cytomegalovirus, rubella, syphilis and HIV. None of the children had these infections. The subjects showed signs of brain calcification – a condition that leads to calcium build-up in the brain.
The theory is that the Zika virus destroys brain cells, and forms lesions where the calcium is deposited.
Investigators have established a strong link between Zika virus infection during pregnancy and microcephaly in infants, but Dr. Jimmy Whitworth, a professor of global public health at the London School of Hygiene and Tropical Medicine, said the latest findings also reveal more of Zika’s harmful consequences.
A baby with microcephaly undergoes physical therapy at a therapy treatment center in Joao Pessoa. Researchers believe that Zika virus could have caused neurological problems that affected the ability of the fetuses to move around the womb.
In other Zika research developments today, a team led by the University of Kansas unveiled a new Zika risk map that accounts for more factors that earlier maps.
“Follow-up studies to determine the exact mechanism responsible for these complications – and to firmly identify Zika as a cause – will be needed”, he said.
The new Zika risk map was recently published on the fast-track publication site of Brazil’s Oswaldo Cruz Institute.
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The U.S. Centers for Disease Control and Prevention provides more information on mosquito-borne diseases.
