Caracterização molecular de enterovírus detectados em crianças com diarreia aguda e em amostras ambientais em Moçambique

Enteroviruses (EV) are enteric pathogens showing global distribution and are etiologic agents of infections ranging from asymptomatic cases to cases of acute gastroenteritis (AGE) and infections in the central nervous system. Due to different clinical effects of that EV infection in the organism, active surveillance system is relevant to provide important information and support to public health policies for prevention and control. The purpose of this study was to characterize EV infection in clinical and environmental samples collected in Mozambique between 2014 and 2018. Two studies were carried out, one in cases of diarrhea and the other in sewage. In the study of cases of diarrhea, 327 fecal samples from children less than 5 years old hospitalized with AGE in health care units in Maputo, Nampula, Sofala and Zambezia provinces from Mozambique between June 2014 and March 2018. Samples were tested by real-time RT-PCR, viral isolation (RD and HEp2C) and subsequent nucleotide sequence of types. Overall, the frequency of EV positive was 15.9% (52/327). The age group from 12 to 23 months was the most affected (p<0.045). Higher positivity of enteroviruses was found in samples with negative results for other enteric pathogens (p<0.011). Enterovirus B was the most prevalent species (40.4%), followed by Enterovirus C with (32.7%) and finally Enterovirus A with (26.9%). Twenty-six types of enteroviruses were detected, and EV-A11 and EV-C99 serotypes the most frequent (17.3% and 15.4, respectively). The EV AGE cases were severe, especially in the 12 to 23-month aged range, with a longer duration of symptoms and hospitalization. Co-detection between enterovirus and other agents was found in 17.3% (09/52). Temperature was positively correlated with enterovirus infection (p<0.006). For the environmental surveillance, sewage samples were collected in the city of Maputo, Mozambique, between January and November 2018. Viral concentration was performed by the silica absorption method and concentrates were inoculated in the RD and L20B cell lines for viral isolation, followed by RT-PCR analysis and subsequent nucleotide sequencing. Of the 63 analyzed samples, 25 (39.7%) were positive for enterovirus, with a high frequency of Enterovirus B species (96%). The coxsackievirus B3 and echovirus 11 were the most frequent types (64%). Phylogenetic analysis of environmental samples revealed that the isolates were closely related to strains associated with neurological diseases. This study identified a wide variety of enteroviruses, including unusual types, in both types of samples studied in Mozambique. The results reinforce the high frequency of EV among cases of GA and the indication of environmental surveillance as a powerful tool to monitor silent viral circulation and the appearance or resurgence of EV, providing valuable information in the context of polio eradication.