Mapeamento hidrológico na região do alto rio Guamá, PA, a partir de imagens PLANET-NICFI.

Na região do Alto Rio Guamá, PA, o processo de ocupação só foi efetivado com a ampliação da malha viária, a partir de 1970. Devido à carência de produtos cartográficos em escala de detalhe, este trabalho visa oferecer uma alternativa para atender demandas locais. Assim, foi realizado o delineamento da rede hidrográfica, considerando a aplicação do Modelo Linear de Mistura Espectral em imagens Planet-NICFI de 2021. Foi observada a eficiência dessas imagens para o mapeamento proposto, reflexo de sua resolução espacial bem fina. Ainda assim, foram observados alguns setores das imagens não classificados pelo método, por não apresentarem em sua construção consistência espectral. Entretanto, a margem de erro do mapeamento foi considerada bem aceitável, pois apenas 40% do total da área associada aos padrões de interesse foram passíveis de ediçõe

Specialized active leprosy search strategies in an endemic area of the Brazilian Amazon identifies a hypermutated Mycobacterium leprae strain causing primary drug resistance

INTRODUCTION: Leprosy, an infectious disease caused by Mycobacterium leprae, remains a public health concern in endemic countries, particularly in Brazil. In this study, we conducted an active surveillance campaign in the hyperendemic city of Castanhal in the northeastern part of the state of Pará using clinical signs and symptoms combined with serological and molecular tools to diagnose new cases and to identify drug resistance of circulating M. leprae strains and their distribution in the community. METHODS: During an active surveillance of one week, we enrolled 318 individuals using three different strategies to enroll subjects for this study: (i) an active survey of previously treated cases from 2006 to 2016 found in the Brazil National Notifiable Disease Information System database (n = 23) and their healthy household contacts (HHC) (n = 57); (ii) an active survey of school children (SC) from two primary public schools in low-income neighborhoods (n = 178), followed by visits to the houses of these newly diagnosed SC (n = 7) to examine their HHC (n = 34) where we diagnosed additional new cases (n = 6); (iii) and those people who spontaneously presented themselves to our team or the local health center with clinical signs and/or symptoms of leprosy (n = 6) with subsequent follow-up of their HHC when the case was confirmed (n = 20) where we diagnosed two additional cases (n = 2). Individuals received a dermato-neurological examination, 5 ml of peripheral blood was collected to assess the anti-PGL-I titer by ELISA and intradermal earlobe skin scrapings were taken from HHC and cases for amplification of the M. leprae RLEP region by qPCR. RESULTS: Anti-PGL-I positivity was highest in the new leprosy case group (52%) followed by the treated group (40.9%), HHC (40%) and lowest in SC (24.6%). RLEP qPCR from SSS was performed on 124 individuals, 22 in treated cases, 24 in newly diagnosed leprosy cases, and 78 in HHC. We detected 29.0% (36/124) positivity overall in this sample set. The positivity in treated cases was 31.8% (7/22), while in newly diagnosed leprosy cases the number of positives were higher, 45.8% (11/23) and lower in HHC at 23.7% (18/76). Whole genome sequencing of M. leprae from biopsies of three infected individuals from one extended family revealed a hypermutated M. leprae strain in an unusual case of primary drug resistance while the other two strains were drug sensitive. DISCUSSION: This study represents the extent of leprosy in an active surveillance campaign during a single week in the city of Castanhal, a city that we have previously surveyed several times during the past ten years. Our results indicate the continuing high transmission of leprosy that includes fairly high rates of new cases detected in children indicating recent spread by multiple foci of infection in the community. An unusual case of a hypermutated M. leprae strain in a case of primary drug resistance was discovered. It also revealed a high hidden prevalence of overt disease and subclinical infection that remains a challenge for correct clinical diagnosis by signs and symptoms that may be aided using adjunct laboratory tests, such as RLEP qPCR and anti-PGL-I serology

Decreased in vitro susceptibility of Plasmodium falciparum isolates to artesunate, mefloquine, chloroquine, and quinine in Cambodia from 2001 to 2007

This study describes the results of in vitro antimalarial susceptibility assays and molecular polymorphisms of Plasmodium falciparum isolates from Cambodia. The samples were collected from patients enrolled in therapeutic efficacy studies (TES) conducted by the Cambodian National Malaria Control Program for the routine efficacy monitoring of artemisinin-based combination therapy (ACT) (artesunate-mefloquine and artemether-lumefantrine combinations). The isolates (n = 2,041) were obtained from nine sentinel sites during the years 2001 to 2007. Among these, 1,588 were examined for their in vitro susceptibilities to four antimalarials (artesunate, mefloquine, chloroquine, and quinine), and 851 isolates were genotyped for single nucleotide polymorphisms (SNPs). The geometric means of the 50% inhibitory concentrations (GMIC(50)s) of the four drugs tested were significantly higher for isolates from western Cambodia than for those from eastern Cambodia. GMIC(50)s for isolates from participants who failed artesunate-mefloquine therapy were significantly higher than those for patients who were cured (P, >0.001). In vitro correlation of artesunate with the other drugs was observed. The distributions of the SNPs differed between eastern and western Cambodia, suggesting different genetic backgrounds of the parasite populations in these two parts of the country. The GMIC(50)s of the four drugs tested increased significantly in eastern Cambodia during 2006 to 2007. These results are worrisome, because they may signal deterioration of the efficacy of artesunate-mefloquine beyond the Cambodian-Thai borde

Evidence of zoonotic leprosy in Pará, Brazilian Amazon, and risks associated with human contact or consumption of armadillos.

Mycobacterium leprae (M. leprae) is a human pathogen and the causative agent for leprosy, a chronic disease characterized by lesions of the skin and peripheral nerve damage. Zoonotic transmission of M. leprae to humans by nine-banded armadillos (Dasypus novemcinctus) has been shown to occur in the southern United States, mainly in Texas, Louisiana, and Florida. Nine-banded armadillos are also common in South America, and residents living in some areas in Brazil hunt and kill armadillos as a dietary source of protein. This study examines the extent of M. leprae infection in wild armadillos and whether these New World mammals may be a natural reservoir for leprosy transmission in Brazil, similar to the situation in the southern states of the U.S. The presence of the M. leprae-specific repetitive sequence RLEP was detected by PCR amplification in purified DNA extracted from armadillo spleen and liver tissue samples. A positive RLEP signal was confirmed in 62% of the armadillos (10/16), indicating high rates of infection with M. leprae. Immunohistochemistry of sections of infected armadillo spleens revealed mycobacterial DNA and cell wall constituents in situ detected by SYBR Gold and auramine/rhodamine staining techniques, respectively. The M. leprae-specific antigen, phenolic glycolipid I (PGL-I) was detected in spleen sections using a rabbit polyclonal antibody specific for PGL-I. Anti-PGL-I titers were assessed by ELISA in sera from 146 inhabitants of Belterra, a hyperendemic city located in western Pará state in Brazil. A positive anti-PGL-I titer is a known biomarker for M. leprae infection in both humans and armadillos. Individuals who consumed armadillo meat most frequently (more than once per month) showed a significantly higher anti-PGL-I titer than those who did not eat or ate less frequently than once per month. Armadillos infected with M. leprae represent a potential environmental reservoir. Consequently, people who hunt, kill, or process or eat armadillo meat are at a higher risk for infection with M. leprae from these animals

Analysis of anti-PGL-I ELISA titer of 146 individuals based on group behaviors.

<p>Behaviors were associated with the type of contact with armadillos, including A) hunting armadillos in the forest, B) handling or preparing armadillo meat for cooking or consumption, C) eating armadillo meat and D) frequency of consuming armadillos in the diet.</p

Staining of mycobacteria <i>in situ</i> in <i>M</i>. <i>leprae</i> infected armadillo spleen sections.

<p>A) SYBR Gold staining (blue) of <i>M</i>. <i>leprae</i> in armadillo spleen A7, arrow denotes stained bacillus. Insert, enlarged area showing stained bacillus. B) SYBR Gold staining (green) of <i>M</i>. <i>leprae</i> in armadillo spleen B7. Arrow denotes stained cluster of bacilli, enlarged in insert. C) Auramine/rhodamine stained cluster (red) of bacilli (arrow) located within an apoptotic cell next to a cell-free necrotic zone (*) in armadillo spleen A7.</p

Hematoxylin and eosin (H&E) and Fite Faraco (acid fast) staining of non-infected and infected armadillo spleen sections.

<p>A) Non-infected control NHDP armadillo spleen (13–02) stained by H&E to show normal splenic architecture; B) <i>M</i>. <i>leprae</i> infected NHDP armadillo spleen (11I302) stained by H&E; C) Non-infected control NHDP armadillo spleen (12–70) stained by Fite Faraco method showing only counterstain; D) Many acid fast bacilli (red clusters) in <i>M</i>. <i>leprae</i> infected NHDP armadillo spleen (11I302) revealed by Fite Faraco stain; E) Wild armadillo (A2) spleen section stained with Fite Faraco, arrow pointing to acid fast bacilli at lower magnification and enlarged in insert; F) Wild armadillo (A2) spleen section stained with Fite Faraco revealing clusters of acid fast bacilli (arrows).</p

Map of study area.

<p>Municipality of Belterra in western Pará, and the villages of São Jorge at Km 92 and Corpus Christi at Km 135 on the Santarém-Cuiabá highway.</p

Risk factors associated with leprosy patients living in rural communities in the municipality of Belterra, Pará.

<p>Risk factors associated with leprosy patients living in rural communities in the municipality of Belterra, Pará.</p