Zika, dengue and chikungunya population prevalence in Rio de Janeiro city, Brazil, and the importance of seroprevalence studies to estimate the real number of infected individuals

Abstract

In the last 40 years, Latin America countries, including Brazil, have suffered from the emergence and reemergence of arboviruses, first Dengue (DENV) and recently Zika (ZIKV) and Chikungunya (CHIKV). All three arboviruses are currently endemic in Brazil and have caused major outbreaks in recent years. Rio de Janeiro city, host of the last Summer Olympic Games and the Football World Cup, has been specially affected by them. A surveillance system based on symptomatic reports is in place in Rio, but the true number of affected individuals is unknown due to the great number of Zika, Dengue and Chikungunya asymptomatic cases. Seroprevalence studies are more suitable to evaluate the real number of cases in a given population. We performed a populational seroprevalence survey in Rio, with recruitment of a sample of volunteers of all ages and gender from July to October 2018, within randomly selected census tracts and household. A total of 2,120 volunteers were interviewed and tested with rapid immunochromatographic test for ZIKV, DENV and CHIKV. Individuals with positive results for IgG and/or IgM from only one virus were classified accordingly, while those with test results positive for both ZIKV and DENV were classified as flaviviruses. We corrected for sample design and non-response in data analysis, and calculated point estimate prevalence and 95% confidence intervals for each virus. Arbovirus prevalence in the Rio's population (n = 6,688,927) was estimated at 48.6% [95% CI 44.8–52.4] (n = 3,254,121) for flaviviruses and at 18.0% [95% CI 14.8–21.2] (n = 1,204,765) for CHIKV. Approximately 17.0% [95% CI 14.1–20.1] (n = 1,145,674) of Rio´s population had no contact with any of the three arboviruses. The reported cases of Zika, Dengue and Chikungunya by the current surveillance system in place is insufficient to estimate their real numbers, and our data indicate that Zika seroprevalence could be at least five times and Chikungunya 45 times bigger. The high number of individuals having never been infected by any of the three arboviruses, may indicate a proper scenario for future outbreaks.

National Holidays and Social Mobility Behaviors: Alternatives for Forecasting COVID-19 Deaths in Brazil

“…To date, the Brazilian scenario has demonstrated that the pandemic just deepened the already-existing political, social, and economic issues in the country [ 7 ]. Although the universal Brazilian public health system has been an example to the world struggling to manage other major outbreaks such as dengue fever, measles, Zika, and chikungunya viruses [ 12 , 13 ], the country has been coping with the several issues that affect COVID-19 prevention. The main ones are the lack of water supply, limited access to hand sanitizers and masks, and the lack of community engagement [ 7 ].…”

Chikungunya virus seroprevalence in asymptomatic blood donors during an outbreak in the Federal District of Brazil

“…The isolated IgG seroprevalence in an urban slum from Salvador (Bahia State) was 11.79% 19 . In Rio de Janeiro city (Southeastern of Brazil), which is distantly located from CHIKV endemic regions, the estimated CHIKV seroprevalence was also higher (17.50%) 20 but this is the main touristic center of Brazil where there might have been different viral introductions. Other factors which can be responsible for the observed low prevalence are the specific year range of the tested donors (34.4 years old) and no history of viral infection prior to donation which might have excluded potentially CHIKV IgG positive individuals from donation of blood.…”

A Chikungunya Virus Multiepitope Recombinant Protein Expressed from the Binary System Insect Cell/Recombinant Baculovirus Is Useful for Laboratorial Diagnosis of Chikungunya

“…Previous studies have shown that the IgG is a more sensitive marker than IgM, in CHIKV infections after a DENV infection [ 53 , 54 ], and the MULTREC IgG-ELISA has proven to be highly reliable for the diagnosis of those cases. Moreover, it is the marker of choice for seroprevalence studies [ 19 , 28 , 29 , 30 ].…”

“…In-house IgG-ELISA has been reported as an accurate and reliable approach to characterize the human immune responses in CHIKV infections [ 1 ]. Moreover, the detection of specific anti-CHIKV IgG antibodies is a consistent strategy used in seroprevalence studies in those areas where DENV and ZIKV co-circulate [ 19 , 28 , 29 , 30 ]. However, in-house ELISAs, a more affordable approach, require viral antigens produced in a limited quantity, by the growth of CHIKV in the brains of mice, which is insufficient for the large-scale serological screening necessary for the spread of the virus.…”