ZIKV Diagnostics: Current Scenario and Future Directions

Abstract

Since the discovery of the Zika virus in Uganda in 1947, diagnostic challenges remain, especially when we take into account the epidemiological context of the surveyed population. Genetic similarities with other flavivirus are responsible for cross-reac tivity during serological evaluation that would often be the only resources to confirm the infection in asymptomatic cases or samples collected after the short window of viral RNA detection. The importance of Zika virus infection diagnosis is undoubtedly useful for pregnant women. This statement became evident after 2015 Brazil's Zika outbreak when a significant increase in cases of newborn with microcephaly was observed. Reverse transcriptase realtime PCR is the most reliable tool for Zika virus infection diagnosis. It detects viral RNA in both biological fluids and tissues and contributes to clinical case classification for initial description of developmental changes observed in neonates exposed congenitally to Zika virus. In conclusion, advances in serological diagnostic are urgent. The safest pathway for these studies requires laborious, subjective, and low throughput PRNT evaluations. Consequently, critical public health questions remain unanswered: how serum prevalent is the general population and pregnant women; can we define risk for congenital Zika syndrome (CZS) and Guillain-Barré syndrome; and how to assess vaccine efficacy and long-term protection.

Zika virus vertical transmission in children with confirmed antenatal exposure

“…As is the case with most congenitally acquired viral infections, such as CMV, rubella, or HIV, PCR of urine and serum (combined) was superior in diagnosing ZIKV infection as compared to serology alone. Urine PCR appeared to be most sensitive yielding the highest proportion of positive results 23 . As urine specimens were collected in 56% of the children in the cohort, higher rates of vertical transmission might have been observed if more urine specimens were obtained.…”

Zika Virus Vertical Transmission in Children With Confirmed Antenatal Exposure

“…As is the case with most congenitally acquired viral infections, such as CMV, rubella, or HIV, PCR of urine and serum (combined) was superior in diagnosing ZIKV infection as compared to serology alone. Urine PCR appeared to be most sensitive yielding the highest proportion of positive results 33 . As urine specimens were collected in 56% of the children in the cohort, higher rates of vertical transmission might have been observed if more urine specimens were obtained.…”