Zika Virus Disease in Colombia — Preliminary Report

Abstract

Background Colombia began official surveillance for Zika virus disease (ZVD) in August 2015. In October 2015, an outbreak of ZVD was declared after laboratory-confirmed disease was identified in nine patients. Methods Using the national population-based surveillance system, we assessed patients with clinical symptoms of ZVD from August 9, 2015, to April 2, 2016. Laboratory test results and pregnancy outcomes were evaluated for a subgroup of pregnant women. Concurrently, we investigated reports of microcephaly for evidence of congenital ZVD. Results By April 2, 2016, there were 65,726 cases of ZVD reported in Colombia, of which 2485 (4%) were confirmed by means of reverse-transcriptase-polymerase-chain-reaction (RT-PCR) assay. The overall reported incidence of ZVD among female patients was twice that in male patients. A total of 11,944 pregnant women with ZVD were reported in Colombia, with 1484 (12%) of these cases confirmed on RT-PCR assay. In a subgroup of 1850 pregnant women, more than 90% of women who were reportedly infected during the third trimester had given birth, and no infants with apparent abnormalities, including microcephaly, have been identified. A majority of the women who contracted ZVD in the first or second trimester were still pregnant at the time of this report. Among the cases of microcephaly investigated from January 2016 through April 2016, four patients had laboratory evidence of congenital ZVD; all were born to asymptomatic mothers who were not included in the ZVD surveillance system. Conclusions Preliminary surveillance data in Colombia suggest that maternal infection with the Zika virus during the third trimester of pregnancy is not linked to structural abnormalities in the fetus. However, the monitoring of the effect of ZVD on pregnant women in Colombia is ongoing. (Funded by Colombian Instituto Nacional de Salud and the Centers for Disease Control and Prevention.).

Impact of Sexual Transmission to Sex-specific Attack Rates in Zika Epidemics

“…Figure 5 shows the ratio AR W (120)/AR M (120) in terms of the intensities of both sexual and vectorial transmission. This effect has been observed in Zika incidence data 10,13,22 but it was frequently confounded with gender-related underreporting, but from our estimates of the male underreporting, we conclude that it can account for only a 20% drop, with the rest of the difference being explained by the excess in female cases due to sexual transmission. This is true even when R 0 < 1, as illustrated in figure 5.…”

Joint Estimation of Relative Risk for Dengue and Zika Infections, Colombia, 2015–2016

“…The Zika epidemic started on August 9, 2015 ( 26 ). Up to the first epidemiologic week of 2017, Colombia reported 106,659 Zika cases (219 cases/100,000 population) that were suspected by clinical signs and confirmed by laboratory.…”

Simulation Model to the Zika Virus Considering Asymptomatic Population

“…Pacheco et al (2016), presented a study on the general context of ZIKV in Colombia, demonstrating the relationship between the virus and microcephaly. At the same time, he gave a report about asymptomatic people to this illness [19]. When the reproduction number varies between 1.9 and 2.8 based on estimates for Antioquia-Colombia, the attack rate varies between 4% and 26% for a low (below 10%) effectiveness of interventions in blunting the ZIKV transmission from symptomatic cases to mosquitoes [20].…”