Publications (20)48.73 Total impact
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Article: Continued Circulation of G12P[6] Rotaviruses Over 28 Months in Nepal: Successive Replacement of Predominant Strains.
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ABSTRACT: Rotavirus A causes severe diarrhoea in infants and young children worldwide. The migration pattern (electropherotype) of the double-stranded RNA genome upon polyacrylamide gel electrophoresis has been used to define "strains" in molecular epidemiology. In temperate countries, distinct electropherotypes (strains) appear after the annual, off-seasonal interruption of rotavirus circulation. In Nepal, rotavirus circulated year-round and an uncommon genotype G12P[6] predominated and persisted, providing a unique opportunity to examine whether the same electropherotype (the same strain) persisted or new electropherotypes (new strains) emerged successively under the same G12P[6] predominance. A total of 147 G12P[6] rotaviruses, collected from diarrhoeal children in Nepal between 2007 and 2010, were classified into 15 distinct electropherotypes (strains). Of these, three electropherotypes (strains), LP1, LP24, and LP27, accounted for 10%, 32% and 38% of the G12P[6] rotaviruses, respectively. Each of the three major strains successively appeared, dominated, and disappeared. This study provided new evidence for the hypothesis that rotavirus constantly changes its strains to predominate in the local population even under conditions where a single genotype predominates and persists. Such dynamic strain replacement, the constant takeover of one predominant strain by another, fitter strain, is probably gives a competitive edge to the survival of rotavirus in nature.Tropical Medicine and Health 03/2013; 41(1):7-12. -
Article: Molecular characterization of multidrug-resistant Mycobacterium tuberculosis isolated in Nepal.
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ABSTRACT: Despite the fact that Nepal is one of the first countries globally to introduce multidrug-resistant tuberculosis (MDR-TB) case management, the number of MDR-TB cases is continuing to rise in Nepal. Rapid molecular tests applicable in this setting to identify resistant organisms would be an effective tool in reversing this trend. To develop such tools, information about the frequency and distribution of mutations that are associated with phenotypic drug resistance in Mycobacterium tuberculosis is required. In the present study, we investigated the prevalence of mutations in rpoB and katG genes and the inhA promoter region in 158 M. tuberculosis isolates (109 phenotypically MDR and 49 non-MDR isolates collected in Nepal) by DNA sequencing. Mutations affecting the 81-bp rifampin (RIF) resistance-determining region (RRDR) of rpoB were identified in 106 of 109 (97.3%) RIF-resistant isolates. Codons 531, 526, and 516 were the most commonly affected, at percentages of 58.7, 15.6, and 15.6%, respectively. Of 113 isoniazid (INH)-resistant isolates, 99 (87.6%) had mutations in the katG gene, with Ser315Thr being the most prevalent (81.4%) substitution. Mutations in the inhA promoter region were detected in 14 (12.4%) INH-resistant isolates. The results from this study provide an overview of the current situation of RIF and INH resistance in M. tuberculosis in Nepal and can serve as a basis for developing or improving rapid molecular tests to monitor drug-resistant strains in this country.Antimicrobial Agents and Chemotherapy 03/2012; 56(6):2831-6. · 4.84 Impact Factor -
Article: Pandemic (H1N1) 2009 virus outbreak in Nepal.
Japanese journal of infectious diseases. 09/2011; 64(5):444-5. -
Article: Changing trends in visceral leishmaniasis: 10 years' experience at a referral hospital in Nepal.
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ABSTRACT: Visceral leishmaniasis (VL) is mainly confined to the southeast area in the Terai region of Nepal. This study aimed to assess time trends and geographical distribution of VL at a referral hospital over a 10-year period in Kathmandu, Nepal. A total of 1521 patients were admitted to the hospital during the study period (April 1999 to March 2009). Overall, 88% of cases were from endemic areas and 10% were from non-endemic areas. There was a significant decreasing trend in the number of VL cases in this hospital during the study period. However, VL is being increasingly diagnosed in patients from non-endemic areas of Nepal. Whether VL in non-endemic areas is imported or autochthonous remains to be elucidated. This study therefore reinforces the need for urgent VL and entomological surveillance in newly reported areas to allow effective VL control strategies to be developed for the future.Transactions of the Royal Society of Tropical Medicine and Hygiene 08/2011; 105(10):550-4. · 2.16 Impact Factor -
Article: Case report: Expansion of visceral leishmaniasis to the western hilly part of Nepal.
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ABSTRACT: We report the first case of visceral leishmaniasis (VL) from the non-endemic western hilly region of Nepal. The patient presented with a history of high-grade fever, abdominal distension, anemia, and weight loss. The case was confirmed as VL by microscopical detection of the Leishmania species amastigote in bone marrow aspiration and by a positive result for the rK39 test. The patient was treated with 0.5-1.0 mg/kg of Amphotericin B for 14 days (total of 405 mg), and amastigotes were negative on discharge. Five months later, this patient again developed fever, abdominal distension, and anemia. Clinical and hematological examinations suggested a relapse of VL. The patient was treated with 1 mg/kg of Amphotericin B for 18 days (total of 515 mg) and was clinically improved on discharge.The American journal of tropical medicine and hygiene 01/2011; 84(1):107-8. · 2.59 Impact Factor -
Article: Diagnosis of visceral leishmaniasis by polymerase chain reaction of DNA extracted from Giemsa's solution-stained slides.
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ABSTRACT: Visceral leishmaniasis (VL) is caused by the protozoan parasite Leishmania donovani and is a potentially fatal disease in endemic areas of the world. Nepal is an endemic area in which VL causes major public health problems in the lowland areas of the southeast regions. The aim of the present study was to evaluate the sensitivity of polymerase chain reaction (PCR) amplification for the detection of Leishmania DNA from Giemsa's solution-stained bone marrow slides. Bone marrow samples were aspirated from a total of 115 VL suspected patients and used to prepare smears on glass slides and for the initiation of in vitro culture. Bone marrow slides were used for microscopic observation, DNA extraction, and subsequent PCR amplification. PCR analysis showed that all the positive samples were of Leishmania parasites. The PCR assay also showed a higher sensitivity (69%) than microscopic examination (57%) and culture (21%). In addition, PCR was able to detect VL in 12% of samples which were negative by microscopy. PCR of DNA extracted from Giemsa's solution-stained bone marrow slides is a suitable tool for confirming diagnosis in patients with VL and may also be useful in the diagnosis of difficult cases. Bone marrow smears are easily stored and can be easily sent to research centers where PCR is available. This makes PCR a good option for diagnosis in the field.Parasitology Research 05/2010; 107(3):727-30. · 2.15 Impact Factor -
Article: Molecular epidemiology of rotavirus diarrhea among children aged <5 years in nepal: predominance of emergent G12 strains during 2 years.
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ABSTRACT: A 2-year surveillance was performed in Kathmandu, Nepal, by collection of stool specimens from 1139 children aged <5 years who were hospitalized for acute diarrhea from November 2005 through October 2007. Of the 1139 samples, 379 (33%) had rotavirus strains identified by enzyme-linked immunosorbent assay; the most prevalent G type was G12, accounting for 50% of typed strains in 2005-2006 and 29% in 2006-2007, followed by G1 (26%) in 2005-2006 and by G9 (28%) and G2 (20%) in 2006-2007. The most prevalent P type was P[8], accounting for 47% of strains in 2005-2006 and 35% in 2006-2007, followed by P[6] (37% in 2005-2006 and 33% in 2006-2007) and P[4] (10% in 2005-2006 and 24% in 2006-2007). Of combined genotypes, G12P[6] was the most prevalent, accounting for 34% of strains in 2005-2006 and 24% in 2006-2007, followed by G1P[8] (23%) in 2005-2006 and G2P[4] (20%) in 2006-2007. An unusually high detection of G12 strains underscores the importance of continued surveillance of rotavirus strains.The Journal of Infectious Diseases 11/2009; 200 Suppl 1:S182-7. · 6.41 Impact Factor -
Article: Loop-mediated isothermal amplification (LAMP) for the direct detection of human pulmonary infections with environmental (nontuberculosis) mycobacteria.
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ABSTRACT: Most first-line anti-tuberculosis drugs have less in vitro activity against atypical mycobacteria. Loop-mediated isothermal amplification (LAMP) was used for the rapid diagnosis of mycobacterial species. The sensitivity of LAMP was 96.1% (49/51) in smear-positive and culture-positive sputum samples and 85.0% (17/20) in smear-negative and culture-positive samples. Of the 77 total LAMP-positive samples, 75 (97.4%) were identified as Mycobacterium tuberculosis and 2 (2.6%) as M. intracellulare. One of the M. intracellulare-infected cases was identified in a patient with suspected mycobacteriosis and another was found in a follow-up patient.Japanese journal of infectious diseases 06/2009; 62(3):212-4. · 1.49 Impact Factor -
Article: Relapse of visceral leishmaniasis after miltefosine treatment in a Nepalese patient.
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ABSTRACT: We report the first case of visceral leishmaniasis (VL) relapse in a healthy individual after complete miltefosine treatment. The patient attended hospital with a history of fever for 2 months, splenomegaly, hepatomegaly, and weight loss. The case was confirmed as VL by microscopical detection of Leishmania parasites in a bone marrow specimen and by a positive result for the immunochromatography-based test targeting the Leishmania donovani rK39 antibody. A polymerase chain reaction (PCR) specific for the Leishmania kinetoplast minicircle gene was positive, and subsequent sequencing of the PCR-amplified product confirmed that this case was a L. donovani infection. The patient was treated with miltefosine for 28 days, during which time the response was good, and the Leishman-Donovan body (LD body) was negative on discharge. Ten months later, however, this patient again developed high fever and splenomegaly, and LD bodies and rK39 antibody were positive, thus indicating a relapse of VL. The patient was subsequently treated with 1 mg/kg of amphotericin B for a total of 14 days and recovered completely.The American journal of tropical medicine and hygiene 05/2009; 80(4):580-2. · 2.59 Impact Factor -
Article: Molecular characterization of Blastocystis isolates from children and rhesus monkeys in Kathmandu, Nepal.
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ABSTRACT: To investigate the possible transmission of Blastocystis organisms between local rhesus monkeys and children in Kathmandu, Nepal, we compared the subtype (ST) and sequence of Blastocystis isolates from children with gastrointestinal symptoms and local rhesus monkeys. Twenty and 10 Blastocystis isolates were established from 82 and 10 fecal samples obtained from children and monkeys, respectively. Subtype analysis with seven sequence-tagged site (STS) primers indicated that the prevalence of Blastocystis sp. ST1, ST2 and ST3 was 20%, 20% and 60% in the child isolates, respectively. In contrast to human isolates, ST3 was not found in monkey isolates and the prevalence of ST1 and ST2 was 50% and 70%, respectively, including three mixed STs1 and 2 and one isolate not amplified by any STS primers, respectively. Since Blastocystis sp. ST2 has been reported as the most dominant genotype in the survey of Blastocystis infection among the various monkey species, sequence comparison of the 150bp variable region of the small subunit rRNA (SSU rRNA) gene was conducted among ST2 isolates of humans and monkeys. Sequence alignment of 24 clones developed from ST2 isolates of 4 humans and 4 monkeys showed three distinct subgroups, defined as ST2A, ST2B and ST2C. These three subgroups were shared between the child and monkey isolates. These results suggest that the local rhesus monkeys are a possible source of Blastocystis sp. ST2 infection of humans in Kathmandu.Veterinary Parasitology 01/2009; 160(3-4):295-300. · 2.58 Impact Factor -
Article: Molecular detection of Leishmania parasites from whole bodies of sandflies collected in Nepal.
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ABSTRACT: Visceral leishmaniasis is endemic in the southern part of the Terai region of Nepal. Natural infections of Phlebotomus species with Leishmania parasites in these endemic areas were analyzed by a polymerase chain reaction (PCR) amplification-based assay. A total of 401 Phlebotomus argentipes and 202 P. papatasi female sandflies were captured in the Dhanusa district from 2004 to 2006 and analyzed. It was found that 6.7% of P. argentipes, but no P. papatasi, were positive for Leishmania parasites, suggesting that P. argentipes is a major vector in these areas. The infectivity of P. argentipes with Leishmania was consistent with the infection rates reported from other areas of the world. This is the first report of naturally infected Leishmania parasites in sandflies collected from Nepal.Parasitology Research 08/2008; 103(2):293-7. · 2.15 Impact Factor -
Article: Development of an in-house loop-mediated isothermal amplification (LAMP) assay for detection of Mycobacterium tuberculosis and evaluation in sputum samples of Nepalese patients.
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ABSTRACT: A number of nucleic acid amplification assays (NAAs) have been employed to detect tubercle bacilli in clinical specimens for tuberculosis (TB) diagnosis. Among these, loop-mediated isothermal amplification (LAMP) is an NAA possessing superior isothermal reaction characteristics. In the present study, a set of six specific primers targeting the Mycobacterium tuberculosis 16S rRNA gene with high sensitivity was selected and a LAMP system (MTB-LAMP) was developed. Using this system, a total of 200 sputum samples from Nepalese patients were investigated. The sensitivity of MTB-LAMP in culture-positive samples was 100 % (96/96), and the specificity in culture-negative samples was 94.2 % (98/104, 95 % confidence interval 90.5-97.9 %). The positive and negative predictive values of MTB-LAMP were 94.1 and 100 %, respectively. These results indicate that this MTB-LAMP method may prove to be a powerful tool for the early diagnosis of TB.Journal of Medical Microbiology 05/2008; 57(Pt 4):439-43. · 2.50 Impact Factor -
Article: Dengue virus, Nepal.
Emerging Infectious Diseases 04/2008; 14(3):514-5. · 6.79 Impact Factor -
Article: Characterization of Leishmania isolates from Nepalese patients with visceral leishmaniasis.
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ABSTRACT: In Nepal, visceral leishmaniasis (VL) is endemic in 13 districts of the central and eastern regions. A total of 166 bone-marrow aspirates were obtained from patients with suspected VL. Ninety-seven were identified as positive by microscopy, and 29 of those were successfully isolated and cultured. We characterized these isolates by molecular analysis and by their ability to infect mice. PCR-restriction fragment length polymorphism analysis of the mini-exon and the cysteine proteinase b gene showed that all isolates were Leishmania donovani, and the restriction pattern of the Nepalese isolates corresponded to the standard Indian strain of L. donovani but differed from that of the Kenyan strain. The single-strand conformation polymorphism analysis of ribosomal internal transcribed spacer showed no genetic heterogeneity within Nepalese isolates. Intraperitoneal inoculation with the promastigotes of all isolates resulted in amastigote proliferation in the spleen of 20 nude mice, of which ten isolates were highly infective, and ten were moderately infective, including one BALB/c mouse. Of the 20 amastigotes isolated from the spleen of nude mice, only the ten highly infective isolates infected BALB/c mice, of which, two isolates were considered to have low infectivity, three isolates were considered to be moderately infective, and five isolates were considered to be highly infective.Parasitology Research 06/2007; 100(6):1361-9. · 2.15 Impact Factor -
Article: Detection of G12 human rotaviruses in Nepal.
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ABSTRACT: Of 731 stool specimens collected from children with diarrhea in Kathmandu, Nepal, from August 2004 through July 2005, 170 (23.3%) tested positive for rotavirus. Reverse transcription-PCR, including a revised G12-specific primer set, identified 56 (32.9%) as G2P[4] and 39 (23.0%) as G12 with P[6], P[8], or P[4].Emerging infectious diseases 04/2007; 13(3):482-4. · 6.17 Impact Factor -
Article: Molecular epidemiology of rotavirus diarrhea among children and adults in Nepal: detection of G12 strains with P[6] or P[8] and a G11P[25] strain.
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ABSTRACT: In anticipation of a rotavirus vaccine in Nepal, this study was undertaken to determine the distribution of the G and P serotypes and electropherotypes of rotaviruses in order to examine if there is any emerging serotype or unusual strain circulating in children and adults in Nepal. Of 1,315 diarrheal stool specimens, rotavirus was detected by an enzyme-linked immunosorbent assay in 116 (17%) of 666 patients less than 5 years of age, in 18 (7%) of 260 patients 5 to 14 years of age, and in 19 (5%) of 358 patients 15 years of age and older. Approximately 75% of rotavirus diarrhea occurred in children less than 5 years of age. Approximately 70% of rotaviruses found in each of the three age groups belonged to serotype G1P[8]. Interestingly, there were 29 (20%) G12 rotaviruses carrying either P[8] or P[6] and one (0.7%) G11 rotavirus carrying an unusual P[25] genotype. RNA polyacrylamide gel electrophoresis discriminated 19 strains (electropherotypes), among which there were three codominant strains carrying G1P[8] and long RNA patterns. Five electropherotypes were discriminated among G12 rotaviruses, all of which had long RNA patterns. The fact that 20% of rotaviruses were G12 strains carrying either P[8] or P[6] and had multiple electropherotypes suggest that G12 strains are not more rare strains but that they pose an emerging challenge to current and future vaccines. The presence of multiple strains as defined by electropherotypes suggests the richness of the rotavirus gene pool in Nepal, where unusual strains may continue to emerge.Journal of Clinical Microbiology 11/2006; 44(10):3499-505. · 4.15 Impact Factor -
Article: First case of cutanous leishmaniasis in Nepalese patient.
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ABSTRACT: Visceral Leishmaniasis (VL) is a serious disease caused by Leishmania donovani (LD) complex and prevalent in the temperate and tropical zones of the earth. VL, endemic in the southern plains of the 14 districts in the Terai region of Nepal, is considered a major public health problem. Cutanous leishmaniasis (CL) is prevalent mainly in the tropics and subtropics, affects nearly 1.5 million people worldwide. No reported cases of CL have been identified in Nepal until now. We report the first case of CL in a Nepalese patient.Nepal Medical College journal : NMCJ. 10/2006; 8(3):213-4. -
Article: First case of Dengue virus infection in Nepal.
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ABSTRACT: Dengue virus transmitted by Aedes mosquito is one of the important cause health problems in world. Dengue fever and more severe and often fatal forms namely dengue hemorrhagic fever and dengue shock syndrome are emerging health problems in many part of the globe. No cases of Dengue virus infection have been reported from Nepal till date and for the first time, we report a case of dengue fever from Nepal.Nepal Medical College journal : NMCJ. 01/2005; 6(2):157-9. -
Article: Etiology of Diarrhoea Among Adult Patients During the Early Monsoon Period in Kathmandu, Nepal
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ABSTRACT: One hundred and eighty-one patients with acute diarrhoea attending the gastroenteritis ward of Sukra Raj Tropical and Infectious Disease Hospital (STIDH) were investigated during the early monsoon, April to May 2001. Bacterial pathogens were isolated in 33% of the patients. Enteropathogenic Escherichia coli was isolated in 8.28%, Shigella species in 13.25% and Vibrio cholerae 01 in 1.1% of the patients. Mixed infections with bacterial pathogens, helminths and protozoan parasites were commonly observed in the study. Trichuris trichiuria was detected in 27.6%, hookworms in 12.7% and Ascaris lumbricoides in 11.04%. Entamoeba histolytica/dispar and Giardia lamblia were observed in 12.7% and 7.73% of the patients, respectively. A large number of Cryptosporidium (7.73%) and Cyclospora species (3.86%) usually present in immunocompromised patients were also detected in acute diarrhoeal cases. The results showed that a wide range of bacterial pathogens was isolated from the inhabitants of Kathmandu, Nepal prior to the monsoon. These findings indicate that the bacterial pathogens, especially diarrhoeaginic E.coli and Shigella, and protozoan parasites, need to be given additional attention in the diagnosis and treatment of acute diarrhoea -
Article: Letters to the Editor
Top co-authors
Top Journals
Institutions
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2006–2013
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Nagasaki University
Nagasaki-shi, Nagasaki-ken, Japan
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2005–2011
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Padma Kanya Multiple Campus
Kathmandu, CR, Nepal
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2009
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Tribhuvan University
Kathmandu, CR, Nepal
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