The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform

Clive R. Davies - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of PCR as a Diagnostic Mass-Screening Tool To Detect Leishmania (Viannia) spp. in Domestic Dogs (Canis familiaris)
    Journal of clinical microbiology, 2003
    Co-Authors: Richard Reithinger, Juan Canales Espinoza, Orin Courtenay, Clive R. Davies
    Abstract:

    Several studies have suggested that the PCR could be used in epidemiological mass-screening surveys to detect Leishmania (Viannia) spp. infection in human and animal hosts. Dogs from an area of Leishmania braziliensis and Leishmania peruviana endemicity were screened for American cutaneous leishmaniasis (ACL) infection by established PCR-based and enzyme-linked immunosorbent antibody test (ELISA) protocols. PCR detected Leishmania (Viannia) infection in a total of 90 of 1,066 (8.4%) dogs: 32 of 368 (8.7%), 65 of 769 (8.5%), and 7 of 42 (16.7%) dogs were PCR positive by testing of whole Blood, Buffy Coat, and bone marrow aspirates, respectively. ELISA detected infection in 221 of 1,059 (20.9%) tested dogs. The high prevalence of Leishmania (Viannia) detected by PCR and ELISA in both asymptomatic (7.5 and 19.2%, respectively) and symptomatic (32 and 62.5%, respectively) dogs is further circumstantial evidence for their suspected role as reservoir hosts of ACL. However, the low sensitivity of PCR (31%) compared to ELISA (81%) indicates that PCR cannot be used for mass screening of samples in ACL epidemiological studies. Unless more-sensitive PCR protocols were to be developed, its use should be restricted to the diagnosis of active (canine and human) cases and to the parasitological monitoring of patients after chemotherapy.

  • Use of PCR To Detect Leishmania(Viannia) spp. in Dog Blood and Bone Marrow
    Journal of clinical microbiology, 2000
    Co-Authors: Richard Reithinger, Bronwen E. Lambson, Douglas C. Barker, Clive R. Davies
    Abstract:

    A PCR-based protocol for the detection of Leishmania ( Viannia ) parasites in canine Blood, Buffy Coat, and bone marrow was developed and was then tested with field samples taken from a random sample of 545 dogs from villages in Peru where Leishmania ( Viannia ) braziliensis and Leishmania ( Viannia ) peruviana are endemic. Comparative tests with cultured parasites mixed with dog Blood showed that the PCR assay9s sensitivity was significantly dependent on the DNA extraction protocol and the PCR primers used. Mass screening of field samples by the preferred PCR protocol detected American cutaneous leishmaniasis (ACL) in 44 of 545 (8.1%) dogs; 31 of 402 (7.7%), 20 of 223 (9.0%), and 8 of 46 (17.4%) were PCR positive when whole Blood, Buffy Coat, and bone marrow aspirates, respectively, were tested. The high prevalence of Leishmania in both asymptomatic (7.6%) and symptomatic (18.0%) dogs provides further circumstantial evidence for their suspected role as reservoir hosts of ACL and indicates that hematogenous dissemination of parasites may be a more common pathological phenomenon than has previously been acknowledged. However, unlike for zoonotic visceral leishmaniasis, the comparatively low prevalence of Leishmania ( Viannia ) in the Blood of symptomatic dogs indicates that PCR with Blood cannot be the “gold standard” for the (mass) screening of samples in epidemiological studies.

Dinesh Mondal - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of PCR-based diagnoses for visceral leishmaniasis in Bangladesh.
    Parasitology international, 2013
    Co-Authors: Gulam Musawwir Khan, Khondaker Rifat Hasan Bhaskar, Dinesh Mondal, Mihoko Kikuchi, M. A. Salam, Tania Akther, Rashidul Haque, Shinjiro Hamano
    Abstract:

    Abstract The diagnosis of visceral leishmaniasis (VL) is performed using multiple methods encompassing parasitological, serological and nucleic acid-based diagnostic tools, each method with its own unique advantages and disadvantages. Conventional parasitological methods are risky for the patient and require skilled personnel to collect specimens from spleen or bone marrow, and hence they are not generally available in impoverished areas. Polymerase chain reaction (PCR) has been validated as an excellent alternative to microscopy in terms of sensitivity and specificity. Here, we evaluate four different PCR assays targeting ITS1, ITS2, mini-exon and small subunit-rRNA (SSUrRNA) using DNA extracted from peripheral Blood Buffy Coat in order to avoid more invasive processes. A total of 61 VL patients and 75 non-VL infected control individuals were enrolled. The VL patients were confirmed to be positive for Leishmania amastigotes in splenic smears by microscopy. Sensitivities of the PCR targeting ITS1, ITS2, SSUrRNA and mini-exon were 96.7%, 91.8%, 88.5% and 34.4%, respectively, while the specificity was 98.7% for all methods. Nested PCR for ITS1 resulted in 100% sensitivity. The efficacy of each PCR was evaluated with various Leishmania amastigote parasite loads in each spleen smear, graded from 1 + to 5 +. The PCR targeting ITS1 showed 100% sensitivity for the detection of Leishmania donovani in all samples from grades ≥ 3, ≥ 4, and ≥ 5, respectively. The restriction fragment length polymorphism observed in ITS1 amplicons digested by Hae III classified the parasite into L. donovani complex. The ITS1 PCR was found to be equal to conventional, but very invasive and risky parasitological diagnoses and superior to other PCR based methods in sensitivity and examination of genetic heterogeneity. We recommend the PCR targeting ITS1 using peripheral Blood Buffy Coat DNA as an alternate, less invasive diagnostic choice for the confirmation of L. donovani infection.

  • peripheral Blood Buffy Coat smear a promising tool for diagnosis of visceral leishmaniasis
    Journal of Clinical Microbiology, 2012
    Co-Authors: Abdus M Salam, Gulam Musawwir M Khan, Khondaker Rifat Hasan Bhaskar, Mokibul Hassan Afrad, Mamun M Huda, Dinesh Mondal
    Abstract:

    Confirmative diagnosis of visceral leishmaniasis (VL) is still a challenge at the primary health care facilities in most of the rural areas of endemicity in the Indian subcontinent. Conventional methods for parasitological confirmation are risky and require skilled personnel, and hence they are unavailable to the poor people in the regions of endemicity. Buffy Coat smear microscopy, as a minimally invasive, simple alternative for the parasitological diagnosis of VL, was evaluated in this prospective study. One hundred twelve VL patients were enrolled in this study. The Buffy Coat was separated from peripheral Blood of all enrolled subjects using Histopaque-1119 solution. Leishman-stained Buffy Coat smears were examined for Leishmania donovani bodies, and Buffy Coat was also utilized for detection of parasite DNA by Leishmania nested PCR (LnPCR) for all cases. Concomitant splenic smears could be examined for L. donovani bodies in 66 cases, and the parasite load was graded on a scale of 1+ to 6+ for L. donovani-positive smears. All splenic smear-positive cases were also found to be positive by LnPCR. Of 112 enrolled VL cases, 103 (92%) were found to be positive for L. donovani bodies in Buffy Coat smear microscopy, which is promising as a confirmative diagnosis tool. We have also found a significant association of the Buffy Coat smear positivity with parasitic burden in the spleen smear. In this preliminary observation in Bangladesh, Buffy Coat smear microscopy has been found to be very simple, minimally invasive, and risk-free method of parasitological diagnosis of VL with a good diagnostic accuracy and potential for field use.

Joo Nam Byun - One of the best experts on this subject based on the ideXlab platform.

  • Effects of Antibiotic Treatment on the Results of Nested PCRs for Scrub Typhus
    Journal of clinical microbiology, 2008
    Co-Authors: Dong-min Kim, Joo Nam Byun
    Abstract:

    In order to determine the effects of antibiotic treatment on the results of nested PCRs for scrub typhus, we investigated the frequency of positive outcomes at various times after antibiotic administration in patients with scrub typhus. The rate of detection by nested PCR with Blood Buffy Coat before antibiotic administration was 90.5%. However, this decreased to 60.5% within 3 days after administration of antibiotics such as doxycycline and rifampin and to 10% by the fourth day following antibiotic administration. Since the sensitivity of nested PCR can be affected by antibiotic administration, clinicians should perform this PCR before antibiotic administration and at the latest within 3 days after antibiotic administration.

Padet Siriyasatien - One of the best experts on this subject based on the ideXlab platform.

  • Detection of Leishmania martiniquensis DNA in various clinical samples by quantitative PCR.
    Tropical biomedicine, 2015
    Co-Authors: S. Jungudomjaroen, Atchara Phumee, Kanyarat Kraivichian, Sarunyou Chusri, Narissara Jariyapan, Sunchai Payungporn, Padet Siriyasatien
    Abstract:

    Leishmaniasis is a neglected tropical parasitic disease affecting a large number of countries in the world. Early diagnosis of Leishmania infections is essential for therapeutic reasons, as it can decrease morbidity and mortality. L. siamensis and L. martiniquensis are novel Leishmania species recently described in Thailand and Myanmar. The disease is usually found in immunocompromised patients, especially those who have AIDS. Currently, the diagnosis of Leishmania infection in Thailand relies on microscopy, microbial culture, and polymerase chain reaction (PCR). In this study, we established a quantitative PCR (qPCR) method for detection of L. martiniquensis DNA in various types of clinical specimens, including whole Blood, Buffy Coat, saliva, and urine of L. martiniquensis infected patients. The results of the qPCR assay were positive in all saliva samples. The assay is therefore effective to detect L. martiniquensis DNA even in noninvasive specimens, and it could be used for the diagnosis, follow up, and survey of L. martiniquensis infections.

  • Detection of Leishmania siamensis DNA in saliva by polymerase chain reaction.
    The American journal of tropical medicine and hygiene, 2013
    Co-Authors: Atchara Phumee, Kanyarat Kraivichian, Sarunyou Chusri, Nopadon Noppakun, Asda Vibhagool, Vivornpun Sanprasert, Vich Tampanya, Henry Wilde, Padet Siriyasatien
    Abstract:

    Polymerase chain reaction was used to detect Leishmania siamensis DNA from clinical samples collected from six leishmaniasis patients during 2011–2012. The samples used in this study came from bone marrow, Blood, Buffy Coat, saliva, urine, and tissue biopsy specimens. Saliva was a good source for L. siamensis DNA by polymerase chain reaction. L. siamensis DNA was also found in saliva of an asymptomatic case-patient. Levels of L. siamensis DNA in saliva decreased until being undetectable after treatment. These levels could be used as a marker to evaluate efficacy of the treatment. A larger study is needed to evaluate this method as a screening and survey tool to study the silent background of Leishmania infection among the at-risk population.

  • Short Report: Detection of Leishmania siamensis DNA in Saliva by Polymerase Chain Reaction
    2013
    Co-Authors: Atchara Phumee, Kanyarat Kraivichian, Asda Vibhagool, Vich Tampanya, Henry Wilde, Padet Siriyasatien
    Abstract:

    Polymerase chain reaction was used to detect Leishmania siamensis DNA from clinical samples collected from six leishmaniasis patients during 2011-2012. The samples used in this study came from bone marrow, Blood, Buffy Coat, saliva, urine, and tissue biopsy specimens. Saliva was a good source for L. siamensis DNA by polymerase chain reaction. L. siamensis DNA was also found in saliva of an asymptomatic case-patient. Levels of L. siamensis DNA in saliva decreased until being undetectable after treatment. These levels could be used as a marker to evaluate efficacy of the treatment. A larger study is needed to evaluate this method as a screening and survey tool to study the silent background of Leishmania infection among the at-risk population.

Maija Leinonen - One of the best experts on this subject based on the ideXlab platform.

  • Detection of Pneumococcus from whole Blood, Buffy Coat and serum samples by PCR during bacteremia in mice.
    APMIS : acta pathologica microbiologica et immunologica Scandinavica, 1999
    Co-Authors: Paula Salo, Kirsi Laitinen, Maija Leinonen
    Abstract:

    Whole Blood, purified leukocyte fraction and serum were investigated as specimens for the detection of pneumococcal bacteremia by polymerase chain reaction (PCR) in mice. The PCR findings were compared to the Blood culture results. Samples were taken from animals 3 and 12 h after intraperitoneal bacterial challenge. The pneumococcal culture was positive in 27% and 77% of Blood samples at 3 and 12 h after challenge, respectively. All whole Blood samples were positive by PCR at both time points. Of the Buffy Coat samples, two of the three pools were PCR-positive at 3 h and all pools at 12 h after bacterial challenge. In the serum sample group, only 40% of the sera were PCR-positive at 3 h, while at 12 h 90% of the samples were PCR-positive. According to these results, whole Blood seems to be the best specimen for the detection of pneumococcal DNA by PCR in bacteremic mice.