BackgroundMelioidosis, caused by Burkholderia pseudomallei, is an endemic disease in Bangladesh. No systematic study has yet been done to detect the environmental source of the organism and its true extent in Bangladesh. The present study attempted to isolate B. pseudomallei in soil samples and to determine its seroprevalence in several districts in Bangladesh.Methodology and ResultsSoil samples were collected from rural areas of four districts of Bangladesh from where culture confirmed melioidosis cases were detected earlier. Multiple soil samples, collected from 5–7 sampling points of 3–5 sites of each district, were cultured in Ashdown selective media. Suspected colonies of B. pseudomallei were identified by biochemical and serological test, and by polymerase chain reaction (PCR) using 16s rRNA specific primers. Blood samples were collected from 940 healthy individuals of four districts to determine anti- B. pseudomallei IgG antibody levels by indirect enzyme linked immunosorbent assay (ELISA) using sonicated crude antigen. Out of 179 soil samples, B. pseudomallei was isolated from two samples of Gazipur district which is located 58 km north of capital Dhaka city. Both the isolates were phenotypically identical, arabinose negative and showed specific 550bp band in PCR. Out of 940 blood samples, anti- B. pseudomallei IgG antibody, higher than the cut-off value (>0.8), was detected in 21.5% individuals. Seropositivity rate was 22.6%-30.8% in three districts from where melioidosis cases were detected earlier, compared to 9.8% in a district where no melioidosis case was either detected or reported (p<0.01). Seropositivity increased with the advancement of age from 5.3% to 30.4% among individuals aged 1–10 years and > 50 years respectively. The seropositivity rates were 26.0% and 20.6% in male and female respectively, while it was 20–27% among different occupational groups. No significant association was observed with gender (χ2 = 3.441, p = 0.064) or any occupational group (χ2 = 3.835, p = 0.280).ConclusionThis is the first study demonstrating the presence of B. pseudomallei in the environmental (soil) samples of Bangladesh. It also suggested that a large proportion of people, residing in these districts, were exposed to the organism.

Melioidosis is known to occur in Bangladesh, but there are few reports about the condition in the published international literature. We set out to review all known cases of melioidosis in the country to date, using both retrospective and prospective data. A web-based literature search was conducted to identify all published case reports, original articles and conference abstracts. Cases were also included from a prospective study conducted in 2017. Fifty-one cases were identified between 1961 and 2017. Cases have been reported from sixteen out of the 64 districts of Bangladesh. The median age of the patients at presentation was 45 years (IQR 37–52), with a significant male (77%) predominance. Many patients (14/39; 36%) were farmers and 83% had diabetes mellitus. A skin/soft tissue abscess was the most common primary clinical presentation (13/49; 27%), followed by septic arthritis (10/49; 20%), pneumonia, and a deep-seated abscess/organ abscess (7/49; 14%). The major challenges to the diagnosis and treatment of melioidosis in Bangladesh are the lack of resources and the lack of awareness of melioidosis. Capacity development programs are urgently required to define the burden of disease and to tackle the mortality rates.

HLA is crucial for appropriate immune responses in several viral infections, as well as in severe acute respiratory syndrome coronavirus‐2 (SARS CoV‐2). The unpredictable nature of Coronavirus Disease 19 (COVID‐19), observed in both inter‐individual and inter‐population level, raises the question, to what extent the HLA, as part of host genetic factors, contribute to disease susceptibility and prognosis. We aimed to identify significant HLAs, those were investigated till now, for their association with COVID‐19. Three databases were searched (PubMed, Cochrane library, and Web of Science) and articles published between January 2020 and May 2021 were included for in‐depth analysis. Two separate teams including four observers independently extracted the summary data, with discrepancies resolved by consensus. This study is registered with PROSPERO (CRD42021251670). Of 1278 studies identified, 36 articles were included consisting of 794,571 participants. Countries from the European region appeared in the highest number of studies and vice versa for countries from South East Asia. Among 117 significantly altered alleles, 85 (72.65%) were found to have a positive correlation with COVID‐19 and 33 (27.35%) alleles were observed having a negative correlation. HLA A*02 is the most investigated allele (n = 18) and showed contradictory results. Non‐classical HLA E was explored by only one study and it showed that E*01:01 is associated with severity. Both in silico and wet lab data were considered and contrasting results were found from two approaches. Although several HLAs depicted significant association, nothing conclusive could be drawn because of heterogeneity in study designs, HLA typing methods, and so forth. This systematic review shows that, though HLAs play role in COVID‐19 susceptibility, severity, and mortality, more uniformly designed, interrelated studies with the inclusion of global data, for use in evidence‐based medicine are needed.

The newly designed primer MK1F/R could be a better alternative for PCR based diagnosis of VL using less invasive sample, peripheral blood instead of bone marrow or spleen aspirates.