Impact of the COVID-19 pandemic on the diagnosis of leprosy in Brazil: An ecological and population-based study

Epidemiological, clinical, and geographical characterization of Leprosy in the County of Santarém-Pará: Insights for effective control and targeted intervention

Leprosy is an infectious disease characterized by slow and chronic evolution, caused by Mycobacterium leprae and or Mycobacterium lepromatosis, an intracellular alcohol-acid-resistant (BAAR) bacillus. The objective of this study was to provide an epidemiological, clinical, and geographic characterization of leprosy in the city of Santarém-Pará during the period 2011-2020. A cross-sectional, descriptive, and quantitative approach was used, employing maps and tables to illustrate clinical and epidemiological variables, including: sex, age, race, area of residence, operational classification, clinical form, number of skin lesions, number of affected nerves, and health units. During the analyzed period, 581 cases of leprosy were diagnosed, resulting in the following cumulative incidence rates: male (60%); age over 15 years (94%); urban area (73%); multibacillary (74%); borderline form (46%); skin lesions greater than 5 (34%); and no nerves affected (68%). In the urban perimeter, a higher cumulative incidence of cases was observed in the central area with 133 cases. However, the health unit reporting the largest number of cases belonged to the southern area, specifically the Basic Health Unit of Nova República, with 48 cases. This study highlights the need to characterize the nuances of leprosy and its variability within the urban environment, according to different areas. Further research is essential to inform the implementation of public policies aimed at addressing the population with the highest vulnerability index, thereby reducing leprosy rates in Santarém.

Spatiotemporal pattern of leprosy in southwest China from 2010 to 2020: an ecological study

BACKGROUND

Despite many efforts to control leprosy worldwide, it is still a significant public health problem in low- and middle-income regions. It has been endemic in China for thousands of years, and southwest China has the highest leprosy burden in the country.

METHODS

This observational study was conducted with all newly detected leprosy cases in southwest China from 2010 to 2020. Data were extracted from the Leprosy Management Information System (LEPMIS) database in China. The Joinpoint model was used to determine the time trends in the study area. Spatial autocorrelation statistics was performed to understand spatial distribution of leprosy cases. Spatial scan statistics was applied to identify significant clusters with high rate.

RESULTS

A total of 4801 newly detected leprosy cases were reported in southwest China over 11 years. The temporal trends declined stably. The new case detection rate (NCDR) dropped from 4.38/1,000,000 population in 2010 to 1.25/1,000,000 population in 2020, with an average decrease of 12.24% (95% CI: -14.0 to - 10.5; P < 0.001). Results of global spatial autocorrelation showed that leprosy cases presented clustering distribution in the study area. Most likely clusters were identified during the study period and were frequently located at Yunnan or the border areas between Yunnan and Guizhou Provinces. Secondary clusters were always located in the western counties, the border areas between Yunnan and Sichuan Provinces.

CONCLUSIONS

Geographic regions characterized by clusters with high rates were considered as leprosy high-risk areas. The findings of this study could be used to design leprosy control measures and provide indications to strengthen the surveillance of high-risk areas. These areas should be prioritized in the allocation of resources.

ncRNAs: an unexplored cellular defense mechanism in leprosy

Leprosy is an infectious disease primarily caused by the obligate intracellular parasite Mycobacterium leprae. Although it has been considered eradicated in many countries, leprosy continues to be a health issue in developing nations. Besides the social stigma associated with it, individuals affected by leprosy may experience nerve damage leading to physical disabilities if the disease is not properly treated or early diagnosed. Leprosy is recognized as a complex disease wherein socioenvironmental factors, immune response, and host genetics interact to contribute to its development. Recently, a new field of study called epigenetics has emerged, revealing that the immune response and other mechanisms related to infectious diseases can be influenced by noncoding RNAs. This review aims to summarize the significant advancements concerning non-coding RNAs in leprosy, discussing the key perspectives on this novel approach to comprehending the pathophysiology of the disease and identifying molecular markers. In our view, investigations on non-coding RNAs in leprosy hold promise and warrant increased attention from researches in this field.

Leprosy in French Guiana, 2015 to 2021: Dynamics of a Persistent Public Health Problem

A resurgence of leprosy as a public health problem in French Guiana was reported over the period 2007 to 2014, particularly among Brazilians gold miners. Prolonged multidrug therapy and reversal reactions represent a therapeutic challenge. The objective of this study was to assess the evolution of leprosy in this European overseas territory. All patients with leprosy confirmed in histopathology between 1 January 2015 and 31 December 2021 were included. A total of 86 patients were included, including 64 new cases and 22 previously diagnosed cases. Sixty patients (70%) were male, 6 cases were paediatric. Brazilian gold miners represented 44.1% of reported occupations (15/34). Maroons represented the second community (13 patients, 15%). Multibacillary and paucibacillary forms were found in 53 (71%) and 22 (29%) patients, respectively. The annual prevalence never exceeded the threshold of 1/10,000. The mean incidence and prevalence were significantly lower than during the period 2007 to 2014 (p < 0.0001). Reversal reactions were found in 29 patients and almost always required a long course of steroids. Infliximab allowed a reduction in the length of treatment with steroids in 2/2 cases. In conclusion, the prevalence of leprosy has decreased significantly in French Guiana, but remains driven by the population of illegal gold miners. Anti-tumour necrosis factor (anti-TNF) drugs represent a promising option in the management of reversal reactions.

Impact of the COVID-19 Pandemic on the Diagnosis of Tuberculosis in Brazil: Is the WHO End TB Strategy at Risk?

Background: In 2014, the World Health Organization (WHO) launched the “post-2015 End TB strategy”, that aims to end the global tuberculosis (TB) epidemic by 2030. However, the COVID-19 pandemic has severely impacted global public health and the strict measures to control the coronavirus spread can affect the management of other diseases, such as TB. Herein, we aimed to assess the impact of the COVID-19 pandemic on the diagnosis of TB in Brazil, during 2020.

Methods: We carried out an ecological and population-based study, using spatial analysis techniques. The variables used were the new cases of TB, pulmonary tuberculosis (PTB), and also baciloscopy-positive (BP) cases in Brazil between 2015 and 2020. The percentage of changes (% change) was calculated to verify if there was an increase or decrease of TB cases in 2020, along with time trend analyses given by Joinpoint regression model. Also, interrupted time series analyses were used to assess the trend of TB diagnosis before and after the onset of the COVID-19 in Brazil. Spatial distribution maps were elaborated, considering the % change of each Brazilian state.

Findings: Data analyses showed a reduction in the diagnosis of TB (−8.3%) and PTB (−8.1%) in Brazil after the irruption of the COVID-19 pandemic. Likewise, 22 states depicted a reduction in TB diagnosis. An expressive reduction of BP cases (−17.1%) was also observed. Interestingly, interrupted time series analysis showed decline in TB and PTB diagnoses from March 2020. Spatial analyses revealed that all states had a progressive reduction of TB, PTB and PB cases, from March on, with the highest percentages of reduction in December (−100% to −75%).

Interpretation: Taken together, our analyses demonstrated a reduction in TB diagnosis after the irruption of the COVID-19 pandemic in Brazil and its regions, signaling a serious impact on the WHO “End TB Strategy” global plan.

Modulation of the Response to Mycobacterium leprae and Pathogenesis of Leprosy

The initial infection by the obligate intracellular bacillus Mycobacterium leprae evolves to leprosy in a small subset of the infected individuals. Transmission is believed to occur mainly by exposure to bacilli present in aerosols expelled by infected individuals with high bacillary load. Mycobacterium leprae-specific DNA has been detected in the blood of asymptomatic household contacts of leprosy patients years before active disease onset, suggesting that, following infection, the bacterium reaches the lymphatic drainage and the blood of at least some individuals. The lower temperature and availability of protected microenvironments may provide the initial conditions for the survival of the bacillus in the airways and skin. A subset of skin-resident macrophages and the Schwann cells of peripheral nerves, two M. leprae permissive cells, may protect M. leprae from effector cells in the initial phase of the infection. The interaction of M. leprae with these cells induces metabolic changes, including the formation of lipid droplets, that are associated with macrophage M2 phenotype and the production of mediators that facilitate the differentiation of specific T cells for M. leprae-expressed antigens to a memory regulatory phenotype. Here, we discuss the possible initials steps of M. leprae infection that may lead to active disease onset, mainly focusing on events prior to the manifestation of the established clinical forms of leprosy. We hypothesize that the progressive differentiation of T cells to the Tregs phenotype inhibits effector function against the bacillus, allowing an increase in the bacillary load and evolution of the infection to active disease. Epigenetic and metabolic mechanisms described in other chronic inflammatory diseases are evaluated for potential application to the understanding of leprosy pathogenesis. A potential role for post-exposure prophylaxis of leprosy in reducing M. leprae-induced anti-inflammatory mediators and, in consequence, Treg/T effector ratios is proposed.