scholarly journals Detection of Orientia tsutsugamushi in Novel Trombiculid Mite Species in Northern Tamil Nadu, India: Use of Targeting the Multicopy traD Gene

2021 ◽  
Author(s):  
John Antony Jude Prakash ◽  
Kannan Kamarasu ◽  
P Philip Samuel ◽  
Renu Govindarajan ◽  
Punitha Govindasamy ◽  
...  
Keyword(s):  
Nested Pcr ◽  
Tamil Nadu ◽  
Scrub Typhus ◽  
Specific Antigen ◽  
Single Copy ◽  
Mite Species ◽  
The Novel ◽  
Orientia Tsutsugamushi ◽  
Potential Vector ◽  
Trombiculid Mite

Abstract Detection of Orientia tsutsugamushi DNA in a trombiculid mite chigger species suggests that it might be a potential vector of scrub typhus in an endemic area. Over a period of 20 mo, 85 rats were trapped, 57 had chiggers that were identified by standard morphometric techniques. The chigger pools were assessed by performing PCR assays targeting fragments of the single-copy genes 56 kDa type-specific antigen gene (TSA56) by nested PCR and the 47 kDa (htrA) quantitative real-time PCR (qPCR). The novel traD SYBR green assay that detects a multicopy gene was also performed. In total, 27 chigger pools were positive by traD qPCR, of which only 7 were positive by 47 kDa qPCR and in 3 of these, 56 kDa gene was amplified by nested PCR. Orientia tsutsugamushi-specific DNA was detected in Ascoschoengastia spp., Schoengastiella ligula, Leptotrombidium rajasthanense, Leptotrombidium deliense, and Leptotrombidium jayawickremei chigger pools. Therefore, they could be potential vectors of scrub typhus in Southern India. The three 56 kDa sequences belonged to TA716 genotype and Kato genogroup. Further studies are needed to confirm these chigger species as scrub typhus vectors in Northern Tamil Nadu.

Protective Immunity of 56-kDa Type-Specific Antigen of Orientia tsutsugamushi Causing Scrub Typhus

2014 ◽  
Vol 24 (12) ◽  
pp. 1728-1735 ◽  
Author(s):  
Sangho Choi ◽  
Hang Jin Jeong ◽  
Young Ran Ju ◽  
Byoungchul Gill ◽  
Kyu-Jam Hwang ◽  
...  
Keyword(s):  
Protective Immunity ◽  
Scrub Typhus ◽  
Specific Antigen ◽  
Orientia Tsutsugamushi

scholarly journals Assessment of a Sensitive qPCR Assay Targeting a Multiple-Copy Gene to Detect Orientia tsutsugamushi DNA

2019 ◽  
Vol 4 (3) ◽  
pp. 113 ◽  
Author(s):  
Chao ◽  
Belinskaya ◽  
Zhang ◽  
Jiang ◽  
Ching
Keyword(s):  
Clinical Utility ◽  
Scrub Typhus ◽  
Limit Of Detection ◽  
Single Copy ◽  
Immunofluorescence Assay ◽  
Clinical Settings ◽  
Orientia Tsutsugamushi ◽  
Multiple Copy ◽  
Molecular Assays ◽  
Copy Gene

Scrub typhus is caused by an obligated intracellular organism, Orientia tsutsugamushi (Orientia). The disease was traditionally thought to be limited in the tsutsugamushi triangle. Recently, scrub typhus has been confirmed in areas outside the triangle. Serological diagnosis of scrub typhus relies on indirect immunofluorescence assay (IFA). Molecular assays such as PCR, qPCR, loop-mediated isothermal amplification, and recombinase polymerase amplification are often targeting a single copy gene. These assays are sensitive and specific, yet they are not broadly used in clinical settings possibly due to low circulating Orientia in blood. In this study, we compared qPCR results using a multiple copy (traD) gene with those using a single copy (47 kDa) gene to assess the improvement of sensitivity and limit of detection. Our results demonstrate that the qPCR using the traD gene provides superior sensitivity in 15 Orientia strains. The limit of detection is below single Orientia genome equivalent and the assay retains specificity with excessive DNA from mouse, chiggers and human. The clinical utility was evaluated using confirmed scrub typhus positive and negative samples. The results show 100% sensitivity and specificity in these samples suggesting that the traD gene qPCR may be useful for clinical diagnosis of Orientia infection.

scholarly journals Detection and Molecular Characterization of Orientia tsutsugamushi from Suspected Scrub Typhus Patients in Mizoram, India

2021 ◽  
Vol 10 (10) ◽  
pp. 514-523
Author(s):  
Vanramliana Gabriel Rosangkima ◽  
Lalnunnemi Ralte Lalremruata ◽  
Christine Vanlalbiakdiki Sailo Hunropuia ◽  
Deborah Lalnghakmawii Lalfakzuala Pautu
Keyword(s):  
Nested Pcr ◽  
Scrub Typhus ◽  
Specific Antigen ◽  
Serum Samples ◽  
Antigen Gene ◽  
Molecular Tests ◽  
Related Genotype ◽  
High Degree ◽  
Higher Sensitivity

Serologic and molecular tests were performed for the diagnosis and to detect O. tsutsugamushi genotypes that are circulating in the state of Mizoram, India. Blood samples from scrub typhus-suspected patients were collected from Synod Hospital, Durtlang, Mizoram. Weil-Felix and immunochromatographic test (ICT) were performed from the serum samples. Nested PCR (nPCR) amplification of 47kDa outer membrane protein antigen gene and 56kDa type-specific antigen gene were done from the whole blood. 141/177 (79.66%) and 134/177 (75.7%) cases showed the presence of antibody against scrub typhus by Weil-Felix and ICT assays respectively. 76/177 (42.93%) patients showed the presence of 47kDa OMP antigen gene by nPCR while 55/177 (31.07%) showed the presence of 56kDa TSA gene by nPCR. Phylogenetic analysis of 56kDa TSA gene sequence revealed that Karp-related genotype was the most common genotype in the study area followed by Kato-related genotype. In this study, a high degree of diversity of O. tsutsugamushi was observed similar to the observations reported from other parts of India. Nested PCR of 47kDa OMP antigen gene showed higher sensitivity as compared to nPCR amplification of 56kDa TSA gene suggesting it as the assay of choice for diagnosis of scrub typhus disease.

scholarly journals Genetic Typing, Based on the 56-Kilodalton Type-Specific Antigen Gene, of Orientia tsutsugamushi Strains Isolated from Chiggers Collected from Wild-Caught Rodents in Taiwan

2011 ◽  
Vol 77 (10) ◽  
pp. 3398-3405 ◽  
Author(s):  
Pey-Ru Lin ◽  
Hui-Ping Tsai ◽  
Pei-Yi Tsui ◽  
Ming-Hui Weng ◽  
Ming-Der Kuo ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Scrub Typhus ◽  
Sequence Similarity ◽  
Specific Antigen ◽  
Febrile Illness ◽  
Prototype Strain ◽  
Asia Pacific ◽  
Orientia Tsutsugamushi ◽  
Content Type ◽  
Strain Characterization

ABSTRACTOrientia tsutsugamushiis the etiological agent of scrub typhus, a mite-borne, febrile illness that occurs in the Asia-Pacific region. We conducted strain characterization ofO. tsutsugamushiisolates from chiggers obtained from rodents based the nucleotide sequence of the 56-kDa outer membrane protein gene. With the use of PCR, a total of 68 DNA sequences of 56-kDa antigen genes were amplified. Phylogenetic analysis revealed that there were at least six definable clusters among the 68 isolates: 37% Karp-related strains (25/68), 27% TA763 strains (18/68), 12% JG-related strains (8/68), 19% Kato-related strains (13/68), 4% divergent strains (3/68), and 1% representing a Gilliam prototype strain (1/68). Overall, theO. tsutsugamushigenotypes exhibited a high degree of diversity, similar to that seen in strains from the rest of the areas where scrub typhus is endemic. Moreover, the 56-kDa protein sequence similarity betweenO. tsutsugamushiisolates from mites and those from human patients (H. Y. Lu et al., Am. J. Trop. Med. Hyg. 83:658-663, 2010) were striking, thus highlighting potential risk factors for this emerging zoonotic disease.

scholarly journals A CASE SERIES ON SCRUB TYPHUS

2021 ◽  
Vol 12 (1) ◽  
pp. 26-28
Author(s):  
Shamsudeen Moideen ◽  
Muhammed Thoyyib MK ◽  
Fathima Zerin Haris ◽  
Anjala Sunny ◽  
Neetha VP
Keyword(s):  
South India ◽  
Scrub Typhus ◽  
Case Series ◽  
Antimicrobial Treatment ◽  
Orientia Tsutsugamushi ◽  
High Grade Fever ◽  
Rickettsial Disease ◽  
Drug Of Choice ◽  
Trombiculid Mite ◽  
Immunofluorescence Antibody

Scrub typhus is a rickettsial disease caused by Orientia tsutsugamushi. It is transmitted to humans via infected chiggers (larva of trombiculid mite). Eschar is a characteristic feature for the diagnosis of scrub typhus and other mite or tick-borne rickettsiosis. Immunofluorescence Antibody (IFA) test is the gold standard for the diagnosis, and doxycycline is the drug of choice for treatment of scrub typhus. We present a case series of scrub typhus in three patients from South India. All three patients presented with high grade fever and IgM scrub typhus was positive status in all cases. Doxycycline 100 mg twice daily for 7 days along with supportive care was effective in all the cases. Serum creatinine levels dropped to normal and renal status of all patients improved well with antimicrobial treatment. Early diagnosis of the infection is necessary as the disease as it can have multiple system involvement and serious complications.

scholarly journals A Clinical Case of Scrub Typhus in the United States Forces Korea Patient with Eschar and Genetic Identification of Orientia tsutsugamushi Using Multiplex PCR-Based Next-Generation Sequencing

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 424
Author(s):  
Seungchan Cho ◽  
Jon C. Allison ◽  
Kkothanahreum Park ◽  
Jin Sun No ◽  
Seung-Ho Lee ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Multiplex Pcr ◽  
Scrub Typhus ◽  
Specific Antigen ◽  
Maculopapular Rash ◽  
The United States ◽  
Genetic Identification ◽  
Orientia Tsutsugamushi ◽  
Next Generation ◽  
Generation Sequencing

An epidemiological investigation was conducted for a scrub typhus case reported in a U.S. Forces Korea military patient in the Republic of Korea in November 2018. The patient had a fever, maculopapular rash, and an eschar. The full-length sequence of Orientia tsutsugamushi 56-kDa type-specific antigen (TSA) gene was obtained from eschar tissue by multiplex PCR-based Next Generation Sequencing for genetic identification. Based on the 56-kDa TSA gene, the O. tsutsugamushi aligned most closely with the Boryong strain.

Multiple eschars in scrub typhus: a case report

2016 ◽  
Vol 47 (1) ◽  
pp. 67-69
Author(s):  
Munegowda Koraluru ◽  
Manideep Nandigam ◽  
Indira Bairy ◽  
Sudha Vidyasagar ◽  
Muralidhar Varma
Keyword(s):  
Scrub Typhus ◽  
Specific Antigen ◽  
Orientia Tsutsugamushi ◽  
Febrile Patient ◽  
Chain Reaction ◽  
Rare Presentation ◽  
Nested Polymerase Chain Reaction ◽  
Appropriate Therapy ◽  
Polymerase Chain ◽  
Edta Blood

Eschar in scrub typhus aids in early diagnosis and institution of appropriate therapy; however, the eschar positivity rates vary greatly in endemic regions. Multiple eschars in scrub typhus are a rare presentation. Our patient presented with fever and multiple eschars and was empirically started on doxycycline. Nested polymerase chain reaction from all the four eschars and from EDTA blood were positive for 56-kDa type-specific antigen which is specific for Orientia tsutsugamushi. The patient recovered completely after 7 days of antibiotic treatment. He was from an area where scrub typhus was not observed previously. An eschar in an acute febrile patient from the “tsutsugamushi triangle” is a valuable sign in scrub typhus diagnosis. A search for multiple eschars in scrub typhus must be made by clinicians.

scholarly journals Abundance & distribution of trombiculid mites & Orientia tsutsugamushi, the vectors & pathogen of scrub typhus in rodents & shrews collected from Puducherry & Tamil Nadu, India

2016 ◽  
Vol 144 (6) ◽  
pp. 893 ◽  
Author(s):  
Sadanandane Candasamy ◽  
Elango Ayyanar ◽  
Kummankottil Paily ◽  
PatriciaAnitha Karthikeyan ◽  
Agatheswaran Sundararajan ◽  
...  
Keyword(s):  
Tamil Nadu ◽  
Scrub Typhus ◽  
Orientia Tsutsugamushi ◽  
Abundance Distribution ◽  
Trombiculid Mites
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