Fiocruz works to develop an unprecedented test for diagnosing acute diarrhea

Developed with the participation of the Oswaldo Cruz Institute (IOC/Fiocruz), the first molecular diagnostic kit for rotavirus and norovirus in Brazil should contribute to the surveillance of pathogens and the investigation of outbreaks of acute diarrhea. The innovation has been approved by the Brazilian Health Regulatory Agency (Anvisa). The quadriplex test allows for four simultaneous investigations, including rotavirus, two norovirus genogroups and an internal control, which increases the reliability of the results.

The kit was developed by the Molecular Biology Institute of Paraná (IBMP) in partnership with the three reference laboratories for rotaviruses in the country, at the request of the General Coordination of Public Health Laboratories of the Ministry of Health (CGLAB/MS). The IOC/Fiocruz participated in the development of the test through the Laboratory of Comparative and Environmental Virology, which acts as a regional reference for rotaviruses with the Ministry of Health and the World Health Organization (WHO). The regional reference laboratory of the Adolfo Lutz Institute (IAL) and the national reference laboratory of the Evandro Chagas Institute (IEC) were also involved.

Experts highlight the importance of the test for public health, considering that norovirus and rotavirus are the main viruses causing acute diarrhea in Brazil and worldwide, with an impact mainly on the health of children under five and the elderly, who are most vulnerable to the disease.

"The kit will enable faster diagnosis in cases of acute diarrhea. This is important during outbreaks, to adopt control measures and, in the context of surveillance, to detect early changes in the transmission of these viruses. It also helps to monitor the effectiveness of rotavirus vaccination, which has significantly reduced infections in Brazil, protecting children from severe cases of diarrhea caused by this agent," says the coordinator of the Regional Reference Laboratory for Rotaviruses at IOC/Fiocruz, Tulio Fumian.

"The kit allows methodological standardization in the country's laboratories, making the results more comparable. Moreover, it is produced with 100% national inputs, which strengthens knowledge and technology in Brazil," says IBMP's in vitro diagnostics coordinator, Irina Riediger.

Molecular diagnosis of rotavirus and norovirus is based on detecting the genetic material of the pathogens in stool samples. Currently, the country's three reference laboratories carry out this detection with their own methodologies, called in-house, using inputs from different suppliers. The new diagnostic kit standardizes the methodology and brings together all the inputs needed for the test, with national reagents produced by the IBMP.

The coordinators of the reference laboratories provided scientific advice for the development of the kit, which underwent two rounds of validation tests, the first at the IBMP, which manufactured the product, and the second at the reference laboratories. "With the in-house methodology, three separate tests are carried out, one for rotavirus and two for norovirus. With the kit, all three tests are carried out at once and the internal control indicates whether the RNA extraction procedure was conducted correctly. This greatly speeds up the tests and makes the results more reliable," explains Fernanda Burlandy, deputy coordinator of the Regional Reference Laboratory for Rotaviruses at IOC/Fiocruz.

The test took around two years to develop. With Anvisa's approval, the kit can be marketed. The adoption of the technology in the Unified Health System (SUS) depends on an evaluation by the National Commission for the Incorporation of Technologies in the SUS (Conitec) and a decision by the Ministry of Health.

According to experts, the test being carried out at the Central Public Health Laboratories (Lacens) in the states could speed up the diagnosis of infections even more. "Today, all states need to send samples to reference laboratories to obtain the molecular diagnosis. With the kit, we will be able to train the Lacens to carry out this test, offering a faster diagnosis," says Tulio.

Public health issue

Acute diarrhea is a serious public health issue. According to the World Health Organization (WHO), this is the third leading cause of death in children under five worldwide. Infections by viruses, bacteria and other parasites are among the most common causes of the disease.

Laboratory diagnosis is important to identify the microorganisms circulating in each location, to guide control measures when outbreaks occur and to monitor the effectiveness of rotavirus vaccination. In Brazil, most cases of diarrhea caused by viruses are associated with norovirus, since rotavirus infections fell after the introduction of the vaccine in 2006.

On the international scene, the impact of the immunizer was confirmed in a study with the participation of IOC/Fiocruz. Based on the monitoring of 28 countries in the Americas, Africa, Europe, Asia and Oceania, the study found that rotaviruses are responsible for 33% of hospitalizations for diarrhea in children under five. The rate drops by half where there is immunization.

In addition to vaccination, access to drinking water and adequate sanitation conditions, as well as hygiene habits, are important measures to prevent infections.