Candidatus Orientia chiloensis causes scrub typhus over a wide geographical range in southern Chile. The life cycle, including vectors and reservoirs of this novel rickettsial pathogen, is incompletely understood. We analyzed rodent tissue and rodent-associated mite samples collected during a field study in six localities on Chiloé Island, where human scrub typhus cases have occurred. Using molecular methods, we detected Orientia DNA in 24.8% of rodents, belonging to five of seven captured species. Orientia-infection rates showed geographical variations, but were not influenced by rodent species, sex, age, and mite infestation. Phylogenetic analysis showed that Orientia sequences from trombiculid mites (Proschoengastia eloisae) were identical to those from scrub typhus patients from the same region. The results suggest that these rodent-associated mites serve as vectors and play an important role in the ecology of scrub typhus in southern Chile. Further studies are required to determine whether Orientia-infected rodents can also serve as reservoir of Orientia in Chile.
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http://dx.doi.org/10.1186/s13071-024-06602-0 | DOI Listing |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC11658049 | PMC |
Parasit Vectors
December 2024
Laboratorio Clínico, Facultad de Medicina Clínica Alemana, Clínica Alemana de Santiago, Universidad del Desarrollo, Santiago, Chile.
Candidatus Orientia chiloensis causes scrub typhus over a wide geographical range in southern Chile. The life cycle, including vectors and reservoirs of this novel rickettsial pathogen, is incompletely understood. We analyzed rodent tissue and rodent-associated mite samples collected during a field study in six localities on Chiloé Island, where human scrub typhus cases have occurred.
View Article and Find Full Text PDFCureus
November 2024
Pharmacology, All India Institute of Medical Sciences, Kalyani, IND.
Introduction Leptospirosis is a zoonotic infection caused by bacteria, which is reemerging in various regions and often poses a diagnostic challenge due to its nonspecific symptoms. While most infections are mild, severe cases occur in 5-10% of patients and are associated with high mortality, especially in areas with poor sanitation and urbanization. This study aims to investigate the association of specific parameters with leptospirosis diagnosis using a machine learning model and geographic mapping tools to identify spatial patterns and high-risk areas for the disease.
View Article and Find Full Text PDFAnimals (Basel)
November 2024
Division of Forest Science, Kangwon National University, Chuncheon 24341, Republic of Korea.
While urbanization leads to habitat loss for medium and large mammals, small mammals can survive in fragmented habitats. As they are known to be the primary hosts of chigger mites (Acari: Trombiculidae) that transmit scrub typhus, their habitat can be considered the primary distribution area for chigger mites. This study aims to examine the distribution of small mammals and chigger mites in four habitat types and analyzed species richness, mean intensity (MI), dominance, and infestation rate (IR).
View Article and Find Full Text PDFJ Assoc Physicians India
December 2024
Professor, Department of Medicine, Indira Gandhi Medical College, Shimla, Himachal Pradesh, India, Corresponding Author.
Aim: To study abnormalities of lipids in patients suffering from severe scrub typhus and their relationship with complications.
Methods: This cohort study was conducted in patients of severe scrub typhus [immunoglobulin (IgM) positive by enzyme-linked immunosorbent assay (ELISA)] admitted to our institute from 1 August 2020 through 31 July 2021. The lipid profile was estimated initially at the time of hospitalization.
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