Leprosy among children in an area without primary health care coverage in Caratateua Island, Brazilian Amazon.

Introduction: The detection of leprosy in children is an important epidemiological marker of the disease, indicating the community's early exposure to Mycobacterium leprae and active transmission of the infection. Methods: In order to detect new cases among children by combining clinical evaluation and laboratory tests, we conducted an active case finding among individuals under 15 years old on Caratateua Island, located in the city of Belém, in the Pará state, an endemic region in the Amazon. Dermato-neurological examination, collection of 5 mL of peripheral blood for IgM anti-PGL-I antibody titration, and intradermal scraping for bacilloscopy and amplification of the specific RLEP region by qPCR were performed. Results: Out of the 56 examined children, 28/56 (50%) new cases were identified. At the time of evaluation, 38/56 (67.8%) children presented one or more clinical alterations. Seropositivity was detected in 7/27 (25.9%) new cases and 5/24 (20.8%) undiagnosed children. DNA amplification of Mycobacterium leprae was observed in 23/28 (82.1%) of new cases and in 5/26 (19.2%) of non-cases. Out of the total cases, 11/28 (39.2%) were exclusively diagnosed by clinical evaluation performed during the active case finding. Seventeen new cases (60.8%) were detected considering the clinical alterations found in addition to positive results for qPCR. In this group, 3/17 (17.6%) qPCR-positive children presented significant clinical changes 5.5 months after the first evaluation. Discussion: Our research detected a number of cases 5.6 times higher compared to the total number of pediatric cases recorded throughout the year 2021 in the municipality of Belém, which shows a critical scenario of underdiagnosing of leprosy among children under 15 years old in the region. We propose the use of qPCR technique to identify new cases among children with oligosymptomatic or early disease in endemic areas, in addition to the training of Primary Health Care professionals and the implementation of the Family Health Strategy coverage in the visited area.

Amerindian genetic ancestry as a risk factor for tuberculosis in an amazonian population.

In recent years, the incidence of tuberculosis (TB) has declined worldwide, although this disease still occurs at relatively high rates in Amerindian populations. This suggests that the genetic ancestry of Amerindians may be an important factor in the development of infections, and may account for at least some of the variation in infection rates in the different populations. The present study investigated the potential influence of Amerindian genetic ancestry on susceptibility to tuberculosis in an Amazon population. The study included 280 patients diagnosed with tuberculosis and 138 asymptomatic hospital employees with no history of TB, but who were in contact with bacterially active TB patients. Ancestry analysis was run on a set of 61 Ancestry-Informative Markers to estimate European, African, and Amerindian genetic ancestry using STRUCTURE v2.2. The TB group had significantly higher Amerindian ancestry in comparison with the control group, and significantly lower European ancestry. Amerindian ancestry in the 20-60% range was found to be the principal risk factor for increased susceptibility to TB. The results of the study indicate that Amerindian ancestry is an important risk factor for susceptibility to TB in the admixed population of the Brazilian Amazon region.

Effect of ancestry on interleukin-10 haplotypes in chronic periodontitis.

Chronic periodontitis is caused by an inflammatory reaction of the periodontal tissues and alveolar bone. This inflammation is caused by periodontopathic bacteria located in the subgingival biofilm, resulting in inflammatory reactions that may lead to loss of attachment. This tissue destruction is a consequence of host immune and inflammatory responses to specific periodontal pathogens and their metabolic products. Cytokines modulate the immune response, altering its efficiency in the competition against pathogens and increasing periodontal susceptibility. This study investigated genetic polymorphisms in Interleukin 10 (A-1082G, C-819T and C-592A) in 205 individuals from an admixed Brazilian population. A significantly increased risk of developing chronic periodontitis was observed in individuals with low IL-10 production and Amerindian ancestry. These results suggest that the polymorphisms A-1082G, C-819T, and C-592A, which are associated with ancestry, are involved in the susceptibility to the development of chronic periodontitis in an admixed northern Brazilian population.