Blood tests reveal broad extent of Zika infection

A new study by UC Berkeley researchers shows that nearly half of the population of Managua, Nicaragua, has been infected with the Zika virus.

Previous infection with the Zika virus imparts immunity to the disease and can help quell future outbreaks.

“Knowing that 50 percent of the population was infected in only a three-month period during the epidemic is important because it means that another epidemic of that size and ferocity in the near future is very unlikely,” said Eva Harris, professor of Infectious Diseases and Vaccinology at the School of Public Health and director of the UC Berkeley Center for Global Public Health.

The researchers tested blood samples of 3,740 children and 1,074 adults from a district in Managua for antibodies to the Zika virus. Thirty percent of children and 56 percent of adults tested positive for Zika virus antibodies; the overall rate was 46 percent.

The team also used the infection rate, known as the seroprevalence, to determine demographic, biological, spatial and environmental risk factors for Zika infection. They found a greater seroprevalence in females than in males, and found that seroprevalence increased with age in children and leveled off with adulthood.

“Seroprevalence studies are important for public health officials and the international scientific community to understand the extent of the Zika epidemic in Nicaragua, and by extension, in Latin America,” says Harris.