A New Possibility for Surveillance: Do We Identify All Cases of Leptospirosis?

Abstract

SUMMARYLeptospirosis is a febrile disease with a typically underestimated global incidence, especially in regions where dengue is endemic. Therefore, it is difficult to accurately determine the number of leptospirosis cases in these areas, which contributes to significant under-reporting this disease. In this study, we estimated the number of possible leptospirosis cases among dengue-like cases that were reported during 2008, 2010, and 2012 in the city of Fortaleza, northeast Brazil. Patients were evaluated for dengue and leptospirosis using immunoenzymatic tests for IgM antibodies that were specific to each pathogen. Among the suspected cases of dengue that resulted as negative in laboratory tests, 10.8% (2008), 19.2% (2010), and 30.8% (2012) were confirmed to be leptospirosis. Considering the cases reported by the surveillance authority as dengue that were subsequently discarded based on the laboratory test results, we estimate that the number of actual leptospirosis cases may be 26 to 49 times higher than those diagnosed and reported by the Health Services. Furthermore, we believe that approximately 20% of dengue-like cases may be leptospirosis cases in areas where the two diseases are endemic.

Human leptospirosis in the Federal District, Brazil, 2011-2015: eco-epidemiological characterization

“…This fi nding reinforces the need for public health policies and management in the FD regarding leptospirosis and other acute febrile diseases (hantavirus, yellow fever, and infl uenza) in addition to dengue fever, which are considered one of the most important public health issues in Brazil 4,15 . Despite leptospirosis having less morbidity than dengue fever in the FD, the lethality of the disease is higher than infections caused by the dengue virus 11 .…”

“…This shows that the highrisk environments for leptospirosis are found throughout the territory, contradicting the idea of restricted areas for disease occurrence 2,6 . However, the absence of PIPs in some regions during the studied period does not exclude the existence of risk environments in these areas and even the occurrence of infection, due to undetected cases 4 .…”

“…Despite leptospirosis having less morbidity than dengue fever in the FD, the lethality of the disease is higher than infections caused by the dengue virus 11 . Another point to consider is that human leptospirosis in the FD may not have all cases reported due to the failure to recognize and diagnose the disease by the public health network 4,5 .…”

“…It is a febrile infectious disease caused by bacteria of the genus Leptospira. The serovars Leptospira icterohaemorraghiae and Leptospira copenhagueni are mainly responsible for severe cases of this disease in humans 3,4 .…”

“…Moreover, bacterium is present in the urine of infected animals and under favorable conditions can remain viable in the environment for months 1,[4][5][6] .…”