Predicting the detection of leprosy in a hyperendemic area of Brazil: Using time series analysis

Abstract

Background: Brazil has the second highest prevalence of leprosy worldwide. Autoregressive integrated moving average models are useful tools in surveillance systems because they provide reliable forecasts from epidemiological time series. Aim: To evaluate the temporal patterns of leprosy detection from 2001 to 2015 and forecast for 2020 in a hyperendemic area in northeastern Brazil. Methods: A cross-sectional study was conducted using monthly leprosy detection from the Brazil information system for notifiable diseases. The Box–Jenkins method was applied to fit a seasonal autoregressive integrated moving average model. Forecasting models (95% prediction interval) were developed to predict leprosy detection for 2020. Results: A total of 44,578 cases were registered with a mean of 247.7 cases per month. The best-fitted model to make forecasts was the seasonal autoregressive integrated moving average ((1,1,1); (1,1,1)). It was predicted 0.32 cases/100,000 inhabitants to January of 2016 and 0.38 cases/100,000 inhabitants to December of 2020. Limitations: This study used secondary data from Brazil information system for notifiable diseases; hence, leprosy data may be underreported. Conclusion: The forecast for leprosy detection rate for December 2020 was < 1 case/100,000 inhabitants. Seasonal autoregressive integrated moving average model has been shown to be appropriate and could be used to forecast leprosy detection rates. Thus, this strategy can be used to facilitate prevention and elimination programmes.

Epidemiological characteristics of leprosy from 2000 to 2019 in a state with low endemicity in southern Brazil

“…As for the level of schooling, not having finished Elementary School was similar to that found in other studies. 16 , 19 , 20 , 21 , 23 As for the area of residence, 84.3% of patients lived in urban areas, data that corroborate the population characteristics of the state of Rio Grande do Sul, where only 15% of people live in rural areas. 10 The sociodemographic variables are similar in different regions of Brazil, with a predominance of males, economically active age group, low level of schooling, and urban residence, with only a certain variation in skin color depending on the region.…”

“…The predominance of cases in these age groups, between 30 and 60 years old, as well as in persons white skin color, is in agreement with data found in the literature. 16 , 19 , 20 , 21 …”

Epidemiological characteristics of leprosy during the period 2005–2020: A retrospective study based on the Chinese surveillance system

“…Furthermore, we observed a higher concentration of new cases detected between July and October, while the lowest was in March. Although leprosy is not traditionally considered a seasonal disease, studies have considered the highest positivity rate for Mycobacterium leprae in the nasal mucosa during the monsoon season ( 39 , 53 ). Our results may support the idea.…”

Leprosy prevalence spatial distribution and trend in a health region in Northeast Brazil, 2008-2017: an ecological study

“…As for the leprosy endemicity pattern, the geographic areas within the UGRSI considered to be of very high endemicity, with emphasis on the municipalities of Governador Edson Lobão, Senador La Rocque, Imperatriz and Davinópolis, have areas that are devoid and/or deficient in terms of basic sanitation and proper waste disposal, as well as environments with high demographic density, which contribute to the maintenance of the pathogen transmission chain and are positively correlated with higher leprosy prevalence. 25 , 26 …”