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Will Brazil's Next Epidemic Come from Another Mosquito-Borne Virus?

JUN 23, 2017 | SARAH ANWAR
Previous studies have shown that co-infection with Chikungunya and Zika may result in prolonged Zika virus RNA shedding, which may increase the severity of infections. “There may be a trend between persistent [Zika virus] RNA shedding and prolonged symptoms,” remarked Contagion® Editorial Advisory Board member Marta G. Cavalcanti, MD, PhD back in February 2017, in a session at the First International Conference on Zika virus. In addition, Dr. Cavalcanti noted that higher morbidity rates were identified among those with Zika and Chikungunya co-infection
Additional research analyzing the impact of the Zika virus epidemic in Brazil was recently published in The Lancet on June 21, 2017. The authors of the Lancet study analyzed the effects of the Zika epidemic in the Brazil between November 2015 and 2016, one year after the Ministry of Health declared Zika a Public Health Emergency of International Concern.
After collecting data on cases of Zika virus infection and microcephaly between January 1, 2015 and November 12, 2016, the authors found that of the total 1,673,272 reported cases of Zika virus in the country, 41,473 (2.5%) were reported to be pregnant women. A total of 1,950 cases of microcephaly resulting from congenital Zika infection were also confirmed.
The researchers discovered that there were “two distinct waves of Zika virus infection” that impacted all regions of Brazil in 2015 and 2016, with most cases occurring in the northeast region of the country after the first wave of Zika. The second wave of Zika was reported to have impacts in all regions of Brazil, and occurred between September 2015 and September 2016. The authors concluded that “occurrence of microcephaly was much lower than that following the first wave of Zika virus infection, reaching epidemic levels in all but the south of Brazil, with estimated monthly peaks varying from 3.2 cases to 15 cases per 10,000 births.”
The Lancet authors concluded, “The distribution of infection-related microcephaly after Zika virus outbreaks has varied across time and Brazilian regions. Reasons for these apparent differences remain to be elucidated.”
Although the Zika epidemic may be over in Brazil, the news of the potential for a Chikungunya epidemic in the same region begs the question, what will the clinical signs be for those with Zika virus infections who also acquire Chikungunya?
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