Vigilância da febre maculosa brasileira na Bahia, 2013 - 2023.

Abstract

Brazilian spotted fever (BSF) is an infectious disease characterized by fever, ranging from mild and atypical forms to severe manifestations, and, if not properly treated, can have a lethality rate of 85.0%. Caused by bacteria of the genus Rickettsia, it is transmitted through the saliva of an infected tick. In Brazil, the most important vector is the tick of the genus Amblyomma. The methodology employed allowed for the identification of registered BSF cases in Bahia between 2013 and 2023, using the Notifiable Diseases Information System (SINAN), Laboratory Environment Manager (GAL), and Mortality Information System (SIM). A descriptive analysis was carried out through an ecological and observational epidemiological study concerning confirmed BSF cases recorded between 2013 and 2023 in Bahia. Results: A total of 176 cases of RMSF were reported, of which 80 were discarded, 51 closed, 28 had no data, and 17 were confirmed, of these 9 by clinical-laboratory criteria and 8 by clinical-epidemiological criteria. Among the reported cases, there was a predominance of males (57.0%) and the most affected age group was 30 to 49 years (21.0%), with a history of contact with ticks. Between July and September, 38.6% of the cases occurred, with August standing out (13.6%). The field 'probable place of infection' had 75.6% incompleteness; among the recorded cases, 12.5% occurred at home, 9.1% at work, 2.8% during leisure, and 1.7% in other settings. The urban area accounted for 61.4% of the notifications, with the Eastern macro-region responsible for 30.7% of the records. The most common signs and symptoms were: fever (81.3%), headache (60.8%), and myalgia (54.5%). Regarding the progression of cases, 51.0% evolved to cure, although the field shows 47.0% incompleteness. As for differential diagnosis (83.5%) and level of education (42.0%) showed incompleteness. FMB was not a direct cause of any death, but two were reported for other causes. Regarding contact with animals, 72.2% reported exposure to ticks, 39.8% to dogs and cats, and 13.6% to cattle. Conclusion: This study revealed that FMB is an important public health concern in the state of Bahia, which has been neglected due to the lack of a specific technical area to monitor it and produce knowledge for the state health surveillance network. State epidemiological surveillance has been able to detect the condition, but only partially, due to many incomplete entries in the SINAN notification and investigation forms, especially in the fields of disease progression, differential diagnosis, probable place of infection, and final classification, which therefore prevented a coherent outline of the epidemiological profile of FMB in Bahia. The analysis also revealed a considerable severity of the disease, as it is distributed across all nine macro-regions of the state. When comparing cases confirmed by SINAN with GAL, no cases were ratified by laboratory analysis according to the Ministry of Health protocol, despite there being two published scientific articles reporting studies of confirmed cases in the state: one in Chapada Diamantina in 2007 and another in the municipality of Ilhéus in 2017. That said, the need for the implementation of active surveillance for FMB in the state of Bahia becomes evident, as well as the qualification of healthcare professionals regarding suspicion, notification, investigation, and timely management of FMB, in order to provide more consistent data that enable more effective assistance to the population as well as characterization of the epidemiological profile of the disease in the state.