The experience of two laboratories at the Instituto Oswaldo Cruz (IOC/Fiocruz), which act as reference services in respiratory viruses and arboviruses, was presented to representatives of Nicaragua at an exchange meeting promoted by the Ministry of Health and the Pan American Health Organization (PAHO). The Nicaraguan delegation was in Brasília, between June 6th and 10th, with the aim of getting to know the health surveillance structures in Brazil. Researchers Paola Resende, from the Laboratory of Respiratory Viruses and Measles, and Ana Bispo de Filippis, head of the Flavivirus Laboratory, participated in activities related to laboratory surveillance.

Reference in respiratory viruses with the Ministry of Health, the Laboratory of Respiratory Viruses and Measles was named as reference in Covid-19 in the Americas by the World Health Organization (WHO) in April 2020. It also acts as a reference in sequencing in the Regional Network of Covid-19 Genomic Surveillance (VOC|GEN) by OPAS. Since 1951, the Laboratory has acted as the National Influenza Center, integrating the global system of surveillance and response to influenza viruses, which is coordinated by the WHO.

In the presentation, Paola Resende detailed the performance of the Genomic Network Fiocruzi in SARS-CoV-2 and influenza surveillance. Made up of F unitsiocruz in nine states and partner institutions, with the collaboration of the Central Public Health Laboratories (Lacens), the network sequenced more than 47 coronavirus genomes, accounting for 32% of the sequencing carried out in Brazil. In addition to fortnightly technical reports sent to the Ministry of Health, the group has been presenting reports on the circulation of SARS-CoV-2 strains, in order to support public policies.

The Network also works with the surveillance of seasonal influenza epidemics, contributing, for example, to the identification of cases of influenza A(H3N2) in 2021 and 2022. According to the scientist, the expansion of the Network's sequencing capacity for genomic sequencing it was an achievement for Brazil during the pandemic period. During this period, as a reference in the COV|GEN network, the Laboratory of Respiratory Viruses and Measles also supported eight countries in the Americas, participating in the sequencing or analysis of 701 SARS-CoV-2 genomes.

The Flavivirus Laboratory of the IOC acts as a regional reference service for different arboviruses with the Ministry of Health, including dengue, yellow fever, chikungunya, Zika and West Nile virus, providing advice to the Ministry of Health and PAHO/WHO. Since the 1980s, the laboratory has been at the forefront of pioneering actions, such as the isolation of different serotypes of the dengue virus in Rio de Janeiro and Brazil and the first detection of the Zika virus genome in the amniotic fluid of women pregnant with babies with microcephaly.

In the lecture, Ana Bispo presented the epidemiological panorama of Brazil, where there is simultaneous circulation of several arboviruses, and the methodologies and algorithms used for the laboratory diagnosis of diseases. Among other topics, the researcher discussed the challenges of this work. In Brazil, between 2017 and 2022, molecular diagnosis was performed in 11% of dengue cases, 21% of chikungunya cases and 40% of Zika cases. The index is reduced because the identification of the genome of the viruses in the blood is only possible in the first days of symptoms of the diseases.

In other cases, the diagnosis is based on serological tests, which detect antibodies in the blood. In this situation, researchers have to deal with the high rate of cross-reactivity that makes it difficult to distinguish between dengue and Zika cases. In addition, there are no commercial serologic tests for yellow fever, Mayaro, and Saint Louis. As for the West Nile virus, commercial tests are not available in Brazil. According to Ana Bispo, 'in house' tests, which use compounds produced in the laboratories themselves, are an alternative in these cases, but the procedure can be difficult outside reference centers.

From the meeting, the researchers of the IOC made themselves available to support Nicaragua in the field of virology. The country is one of the poorest in Latin America. In the ranking of the Human Development Index, released by the United Nations Development Program (UNDP) based on data from 2019, Nicaragua occupies the 128th position, ahead only of Honduras and Haiti, among the countries in the region. Brazil is in position 84.