http://http://dspace.icddrb.org:80/jspui/handle/123456789/5911 2026-04-05T22:38:28Z 2026-04-05T22:38:28Z Alam, Mohammad Shafiul Ghosh, Debashis Khan, Md Gulam Musawwir Islam, Mohammad Faizul Mondal, Dinesh Itoh, Makoto Islam, Md Nurul Haque, Rashidul http://http://dspace.icddrb.org:80/jspui/handle/123456789/6200 2016-05-22T03:44:10Z 2011-01-01T00:00:00Z

Title: Survey of domestic cattle for anti-Leishmania antibodies and Leishmania DNA in a visceral leishmaniasis endemic area of Bangladesh Authors: Alam, Mohammad Shafiul; Ghosh, Debashis; Khan, Md Gulam Musawwir; Islam, Mohammad Faizul; Mondal, Dinesh; Itoh, Makoto; Islam, Md Nurul; Haque, Rashidul Abstract: Background: Visceral leishmaniasis (VL), caused by an intracellular parasite Leishmania donovani in the Indian subcontinent, is considered to be anthroponotic. The role of domestic animals in its transmission is still unclear. Although cattle are the preferred blood host for Phlebotomus argentipes, the sandfly vector of VL in the Indian subcontinent, very little information is available for their role in the disease transmission. In this study, we examined domestic cattle for serological and molecular evidence of Leishmania infection in a VL-endemic area in Bangladesh. Blood samples from 138 domestic cattle were collected from houses with active or recently-treated VL and post-kala-azar dermal leishmaniasis patients. The presence of anti-leishmanial antibodies in serum was investigated using enzyme-linked immunosorbent assay (ELISA) and then with direct agglutination tests (DAT). Nested PCR (Ln PCR) was performed to amplify the ssu-rRNA gene using the DNA extracted from Buffy coat. Recently-developed molecular assay loop-mediated isothermal amplification (LAMP) was also performed for further sensitive detection of parasite DNA. Results: In this study, 9.4% (n = 13) of the cattle were found to be positive by ELISA. Of the 13 ELISA-positive cattle, only four (30.8%) were positive in DAT. Parasite DNA was not detected in either of the molecular assays (Ln PCR and LAMP). Conclusions: The study confirmed the presence of antibodies against Leishmania parasite in cattle. However, the absence of Leishmania DNA in the cattle indicates clearly that the cattle do not play a role as reservoir host. Similar study needs to be undertaken in the Indian subcontinent to determine the role of other domestic animals on which sandflies feed.

2011-01-01T00:00:00Z Alam, Mohammad Shafiul Mohon, Abu Naser Mustafa, Shariar Khan, Wasif Ali Islam, Nazrul Karim, Mohammad Jahirul Khanum, Hamida Sullivan, David J Jr. Haque, Rashidul http://http://dspace.icddrb.org:80/jspui/handle/123456789/6199 2016-05-22T03:31:25Z 2011-01-01T00:00:00Z

Title: Real-time PCR assay and rapid diagnostic tests for the diagnosis of clinically suspected malaria patients in Bangladesh Authors: Alam, Mohammad Shafiul; Mohon, Abu Naser; Mustafa, Shariar; Khan, Wasif Ali; Islam, Nazrul; Karim, Mohammad Jahirul; Khanum, Hamida; Sullivan, David J Jr.; Haque, Rashidul Abstract: Background: More than 95% of total malaria cases in Bangladesh are reported from the 13 high endemic districts. Plasmodium falciparum and Plasmodium vivax are the two most abundant malaria parasites in the country. To improve the detection and management of malaria patients, the National Malaria Control Programme (NMCP) has been using rapid diagnostic test (RDT) in the endemic areas. A study was conducted to establish a SYBR Greenbased modified real-time PCR assay as a gold standard to evaluate the performance of four commercially-available malaria RDTs, along with the classical gold standard- microscopy. Methods: Blood samples were collected from 338 febrile patients referred for the diagnosis of malaria by the attending physician at Matiranga Upazila Health Complex (UHC) from May 2009 to August 2010. Paracheck RDT and microscopy were performed at the UHC. The blood samples were preserved in EDTA tubes. A SYBR Green-based real-time PCR assay was performed and evaluated. The performances of the remaining three RDTs (Falcivax, Onsite Pf and Onsite Pf/Pv) were also evaluated against microscopy and real-time PCR using the stored blood samples. Result: In total, 338 febrile patients were enrolled in the study. Malaria parasites were detected in 189 (55.9%) and 188 (55.6%) patients by microscopy and real-time PCR respectively. Among the RDTs, the highest sensitivity for the detection of P. falciparum (including mixed infection) was obtained by Paracheck [98.8%, 95% confidence interval (CI) 95.8-99.9] and Falcivax (97.6%, 95% CI 94.1-99.4) compared to microscopy and real-time PCR respectively. Paracheck and Onsite Pf/Pv gave the highest specificity (98.8%, 95% CI 95.7-99.9) compared to microscopy and Onsite Pf/Pv (98.8, 95% CI 95.8-99.9) compared to real-time PCR respectively for the detection of P. falciparum. On the other hand Falcivax and Onsite Pf/Pv had equal sensitivity (90.5%, 95% CI 69.6-98.8) and almost 100% specificity compared to microscopy for the detection of P. vivax. However, compared to real-time PCR assay RDTs and microscopy gave low sensitivity (76.9%, 95% CI 56.4-91) in detecting of P. vivax although a very high specificity was obtained (99- 100%). Conclusion: The results of this study suggest that the SYBR Green-based real-time PCR assay could be used as an alternative gold standard method in a reference setting. Commercially-available RDTs used in the study are quite sensitive and specific in detecting P. falciparum, although their sensitivity in detecting P. vivax was not satisfactory compared to the real-time PCR assay.

2011-01-01T00:00:00Z Alam, Mohammad Murshid Riyadh, M. Asrafuzzaman Fatema, Kaniz Rahman, Mohammad Arif Akhtar, Nayeema Ahmed, Tanvir Chowdhury, Mohiul Islam Chowdhury, Fahima Calderwood, Stephen B. Harris, Jason B. Ryan, Edward T. Qadri, Firdausi http://http://dspace.icddrb.org:80/jspui/handle/123456789/6198 2016-05-22T03:16:36Z 2011-01-01T00:00:00Z

Title: Antigen-specific memory B-cell responses in Bangladeshi adults after one or two dose oral killed cholera vaccination, and comparison with responses following natural cholera Authors: Alam, Mohammad Murshid; Riyadh, M. Asrafuzzaman; Fatema, Kaniz; Rahman, Mohammad Arif; Akhtar, Nayeema; Ahmed, Tanvir; Chowdhury, Mohiul Islam; Chowdhury, Fahima; Calderwood, Stephen B.; Harris, Jason B.; Ryan, Edward T.; Qadri, Firdausi Abstract: The mediators of protective immunity against cholera are currently unknown, but memory B-cell responses may play a central role in facilitating long-term and anamnestic responses against Vibrio cholerae, the cause of cholera. We compared memory B-cell responses in adults with natural cholera in Bangladesh (n 70) to responses in Bangladeshi adults after one-dose (n 30) or two-dose (n 30) administration of an oral killed cholera vaccine, WC-rBS (Dukoral; Crucell), assessing the responses at the acute stage of disease or prevaccination and then on days 3, 30, 90, 180, 270, and 360. Individuals with natural cholera developed prominent vibriocidal and plasma anti-cholera toxin B subunit (CtxB) and lipopolysaccharide (LPS) IgG and IgA responses, but these responses returned to baseline by 1 year of follow-up. Vaccinees developed plasma anti-CtxB and anti-LPS IgG and IgA responses that were generally comparable to those in individuals recovering from natural disease, but vibriocidal responses were lower in vaccinees than in infected patients. Individuals recovering from natural disease developed memory B-cell IgG and IgA anti-CtxB and anti-LPS responses by day 30, and these responses were detectable through at least days 180 to 360. In contrast, we detected no IgA or IgG memory B-cell responses to LPS in vaccinees; anti-CtxB IgA responses were only detectable on day 30, and anti-CtxB IgG responses were detectable until days 90 to 180, compared to days 270 to 360 in patients. These findings may explain in part the relatively short-term protection afforded by oral cholera vaccination compared to natural disease.

2011-01-01T00:00:00Z