Epidemiologic and clinical investigations during a chikungunya outbreak in Rio Grande do Norte State, Brazil.

The first autochthonous case of chikungunya virus (CHIKV) infection in Brazil was in September 2014 in the State of Amapá, and from there it rapidly spread across the country. The present study was conducted in 2016 in the state of Rio Grande do Norte, and the aims were to describe the epidemiological and the clinical aspects of the CHIKV outbreak. Biological samples from 284 chikungunya suspected cases were screened for CHIKV and Flavivirus (FV) RNA using qRT-PCR. Negative PCR samples were also screened for anti-CHIKV and anti-FVIgM by ELISA. CHIKV RNA were detected in 125 samples mostly occurring from January through March (46%), mainly affecting adults and older adults. We found a gradual decrease in viral RNA over the disease time. Anti-CHIKV IgM was found in 47.5% after negative CHIKV qRT-PCR. Interestingly, 45.0% simultaneously had positive results for CHIKV and FV IgM, suggesting the occurrence of virus co-circulation. The most frequent symptom was fever (91%). Women presented more chance to develop nausea and abdominal pain compared to men. Our data described and allows us to better understand the clinical and epidemiological aspects of the 2016 chikungunya outbreak in Rio Grande do Norte and can help in the early clinical diagnosis of the virus.

Spatio-temporal dynamics of Aedes aegypti and Aedes albopictus oviposition in an urban area of northeastern Brazil.

OBJECTIVE: The objective of this study was to analyse abundance and spatial distribution of Aedes aegypti and Aedes albopictus oviposition in the city of Natal-RN, 2016 to 2018. METHODS: Three hundred and seven oviposition traps were installed covered the whole city and were monitored weekly from January 2016 to December 2018. To verify the abundance of the vector based on its location, the formation of oviposition clusters was studied using the Kernel statistics. Egg Density Index (EDI) and Oviposition Positivity Index (OPI) values were calculated. RESULTS: Temperature and humidity presented weak and very weak correlation, respectively, with the oviposition indicators. The median of oviposition positivity index (OPI) was 60.5%, and the egg density index (EDI) was 45.4 eggs/trap. The OPI (71.1%) was higher in the second quarter of the year. The areas with the most persistent oviposition are located in a continuous strip that extends from the extreme of the northern district and extends along the western district of the city. Also noteworthy is the proximity to the strategic points. CONCLUSION: The spatio-temporal distribution of oviposition revealed that there is spatial segregation and marked seasonality. Therefore, this study highlights the importance of maintaining surveillance targeting and control strategies focused on these areas, especially during the most important period of the year.

OBJECTIF: L'objectif de cette étude était d'analyser l'abondance et la distribution spatiale de la ponte d'Aedes aegypti et d'Aedes albopictus dans la ville de Natal-RN, de 2016 à 2018. MÉTHODES: 307 pièges de ponte ont été installés dans toute la ville et surveillés chaque semaine de janvier 2016 à décembre 2018. Pour vérifier l'abondance du vecteur en fonction de sa localisation, la formation de grappes de ponte a été étudiée à l'aide des statistiques de Kernel. Les valeurs de l'indice de densité des œufs (IDO) et de l'indice de positivité de la ponte(IPP) ont été calculées. RÉSULTATS: La température et l'humidité ont présenté une corrélation faible et très faible, respectivement, avec les indicateurs de ponte. L'indice médian de positivité de ponte (IPP) était de 60,5% et l'indice de densité des œufs (IDO) était de 45,4 œufs/piège. L'IPP (71,1%) était plus élevé au deuxième trimestre de l'année. Les zones avec la ponte la plus persistante sont situées dans une bande continue qui s'étend de l'extrémité du district nord et s'étend le long du district ouest de la ville. A noter également la proximité des points stratégiques. CONCLUSIONS: La distribution spatiotemporelle de la ponte a révélé une ségrégation spatiale et une saisonnalité marquée. Par conséquent, cette étude met en évidence l'importance de maintenir des stratégies de surveillance ciblée et de contrôle axés sur ces zones, en particulier pendant la période la plus importante de l'année.

Identification of surveillance and control priority areas for dengue and other arboviruses transmitted by Aedes aegypti in Natal-RN, Brazil: experience report. / Identificação de áreas prioritárias para a vigilância e controle de dengue e outras arboviroses transmitidas pelo Aedes aegypti no município de Natal-RN: relato de experiência.

OBJECTIVE: to report the vigi@dengue experience, held in the municipality of Natal-RN, Brazil, from October/2015 to May/2016. METHODS: entomological indicators were obtained from the oviposition traps, epidemiological indicators from notifications on the online Information System for Notifiable Diseases (Sinan-dengue), active search for cases and viral RNA detection (RTq-PCR) in arthropods and human serum samples; risk levels have been created based on these indicators; categories of interventions for each risk level have been established. RESULTS: early identification of epidemics in three areas of the municipality, with guidance for field work for the most vulnerable areas; the municipality presented ovitrap positivity index (OPI) of 40% and eggs density index (EDI) of 51 eggs/ovitraps; identification of CHIKV, DENV-1 and DENV-3 in Natal-RN. CONCLUSION: the strategy identified the early emergence of epidemics in specific locations; it was helpful in the guidance of control measures for the areas of major risk.