Background & Objectives: Human cases of scrub typhus are reported every year from Puducherry and adjoining areas in southern India. However, information on the presence of causative agent, Orientia tsutsugamushi, and its vectors is lacking. Hence, the objective of the study was to find out the vector as well as pathogen distribution in rodents and shrews present in the scrub typhus-reported areas in southern India.
Methods: Trombiculid mites were collected by combing rats and shrews collected using Sherman traps and identified to species level following standard taxonomical keys. The serum samples of the animals were used for Weil-Felix test and the clots containing blood cells were used for DNA extraction and polymerase chain reaction (PCR).
Results: A total of 181 animals comprising four rodent species and one shrew species were collected from 12 villages. High proportion of chiggers was collected from the shrew, Suncus murinus (79.1%) and Rattus rattus (47.6%). A total of 10,491 trombiculid mites belonging to nine species were collected. Leptotrombidium deliense, the known vector of scrub typhus pathogen, was the predominant species (71.0%) and the chigger (L. deliense) index was 41.1 per animal. Of the 50 animals screened for the pathogen, 28 showed agglutination against OX-K in Weil-Felix test indicating the presence of antibodies against O. tsutsugamushi, the causative agent of scrub typhus. PCR carried out with the DNA extracted from blood samples of two of the animals were positive for GroEl gene of O. tsutsugamushi.
Interpretation & Conclusions: L. deliense index was well above the critical limit of chigger load, indicating that all the villages were receptive for high risk of transmission of scrub typhus to human. Pathogen positivity was higher among animals collected from villages recorded for higher chigger indices due to active transmission between the chigger mites and reservoir host animals. The results are suggestive of routine vector/pathogen surveillance at hot spots to initiate timely preventive measures.
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http://dx.doi.org/10.4103/ijmr.IJMR_1390_15 | DOI Listing |
Infect Chemother
December 2024
Division of Infectious Diseases, Department of Internal Medicine, Inha University School of Medicine, Incheon, Korea.
Tsutsugamushi disease is a febrile mite-borne disease caused by . Before 1945, this disease had been prevalent in Niigata, Akita, and Yamagata prefectures for centuries, occurring in areas along major rivers in these prefectures every summer about a month after floods. The patients affected were farmers, possibly new settlers on reclaimed lands, who contracted the disease following bites of tiny red bugs.
View Article and Find Full Text PDFIndian Pediatr
January 2025
ICMR Regional Medical Research Centre, Gorakhpur, Uttar Pradesh, India. Correspondence to: Dr Manoj Murhekar, Director-in-Charge, ICMR-Regional Medical Research Centre, Gorakhpur, Uttar Pradesh, India 273013.
Objective: To estimate the proportion of children with acute febrile illness (AFI) attending the peripheral health facilities in Gorakhpur, Uttar Pradesh, India, due to Orientia tsutsugamushi (Ots) and re-evaluate the strategy of presumptive administration of doxycycline/azithromycin (PDA) to patients with AFI.
Methods: Children aged 2-18 years with AFI attending 16 peripheral health facilities in Gorakhpur, Uttar Pradesh, were enrolled in September 2023. Blood samples were tested for O.
Indian J Pediatr
December 2024
Department of Pediatrics, Gauhati Medical College, Guwahati, 781032, India.
New Microbes New Infect
December 2024
National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 102206, Changping District, Beijing City, China.
Acute encephalitis syndrome (AES) is a significant public health issue in India, attributed to various etiologies. In eastern Uttar Pradesh, Japanese encephalitis (JE) was the leading cause of AES (10-14% of total AES) until scrub typhus (ST), caused by , was identified in cerebrospinal fluid and blood samples of AES patients contributing more than 60% of AES cases. This study investigates the prevalence of JE-ST coinfection and compares clinical outcomes among JE mono-infection, ST mono-infection, and JE-ST coinfection.
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