Md. Ariful Islam

A review of Brucella seroprevalence among humans and animals in Bangladesh with special emphasis on epidemiology, risk factors and control opportunities

Brucellosis is a neglected bacterial zoonotic disease in many countries affecting both humans and animals. The aim of this paper is to review published reports of the seroprevalence of brucellosis in humans and animals (cattle, buffalo, sheep, goats and dogs) in Bangladesh. The prevalence studies are based primarily on the following serological tests: rose bengal plate agglutination test (RBT), plate agglutination test (PAT), tube agglutination test (TAT), mercaptoethanol agglutination test (MET), standard tube agglutination test (STAT), slow agglutination test (SAT), milk ring test (MRT), indirect enzyme-linked immunosorbant assay (I-ELISA), competitive ELISA (C-ELISA) and fluorescent polarization assay (FPA). Seroprevalences of brucellosis were found to be affected by the sensitivity and specificity of serological tests employed. Brucellosis prevalence varied based on occupations of people (2.5-18.6%) and species of animals (3.7% in cattle, 4.0% in buffalo, 3.6% in goats and 7.3% in sheep). The prevalence of brucellosis in humans was reported in livestock farmers (2.6-21.6%), milkers (18.6%), butchers (2.5%) and veterinarians (5.3-11.1%) who have direct contact with animal and its products or who consume raw milk. According to published reports brucellosis does affect people and livestock of Bangladesh. There is an immediate need for a concerted effort to control and eradicate brucellosis from domesticated animals in Bangladesh.

Simple synthesis process for ZnO sphere-decorated CNT fiber and its electrical, optical, thermal, and mechanical properties

An easy process to produce ZnO sphere-decorated CNT (ZSDC) fibers was established. The prepared ZSDC fibers showed aggregated ZnO nanoparticles deposited homogenously as spheres on the CNT fiber surfaces and non-aggregated ZnO nanoparticles invading the inside of the fiber and occupying the gaps among the individual CNTs. The ZnO nanoparticles inside the fiber acted as cross linkers of the individual CNTs by chemical bonding, which improved the Youngs modulus and tensile strength of the ZSDC fiber by 340% and 60%, respectively, when compared with bare CNT fiber. The ZSDC fiber exhibited superior light absorption properties throughout the entire region of the visible to near-IR (NIR) spectrum (400–2100 nm) as well as higher thermal stability at 880 °C in a nitrogen environment compared to the bare CNT fiber. In addition, the composite fiber showed very high electrical conductivity (983 S cm−1). This high electrical conductivity suggests that electron movement through the fiber is not hampered by the semi-conductive ZnO nanoparticles. A unique high intensity radial breathing mode (RBM) peak was observed in the Raman spectrum of the ZSDC fiber, whereas the bare CNT fiber did not show a RBM peak. This RBM peak of the ZSDC fiber indicates that there is a special arrangement of ZnO nanoparticles caused by chemical bonding that generates this RBM mode of the CNT fiber in ZSDC.

Novel synthesis process for solar-light-active porous carbon-doped CuO nanoribbon and its photocatalytic application for the degradation of an organic dye

A simple, one-step novel solution process was developed for the synthesis of carbon-doped CuO (C-CuO) nanoribbons without the use of a catalyst, template, substrate, or costly instrumentation at room temperature. The precursor materials used were converted into C-CuO nanoribbons in ethanol (95%) at high concentrations (4.37 mg mL−1) as a colloidal solution with very high dispersion stability. The simplicity, reaction time, production cost, production yield, and environmental friendliness of this process make it suitable for the large-scale industrial production of C-CuO nanoribbons. The prepared nanoribbon is also separable and redispersible in other organic solvents. The dispersibility in multiple solvents highlights its versatility as a platform for depositing other nanomaterials on its surface in organic media to improve its additional properties as a candidate for other applications. Its three-dimensional surface morphology was characterized, which suggested that the prepared C-CuO nanoribbon was highly porous. Free-standing C-CuO nanoribbon films were also prepared using a simple process. The prepared film of porous C-CuO nanoribbon exhibited excellent light absorption ability in the range from visible to near-IR light with higher intensity. The superior light absorption properties of the C-CuO nanoribbons were utilized in a photocatalyst to decompose an organic dye in visible light. The degradation of the organic dye (96.64%), recycling performance (93.94%), number of cycles (24), and degradation time (120 min) highlight its potential as a very good photocatalyst.

The First Detection of Brucella canis in Cattle in the Republic of Korea

Twenty mammary lymph node samples were collected from cattle on a farm in the Republic of Korea. These cattle were serologically negative for Brucella by tube agglutination test (≤1 : 50) and serum agglutination test (≤1 : 50). Out of 20 lymph node samples, two samples were positive for Brucella growth on Brucella agar as well as blood agar. Tests for urease, hydrogen sulphide and reactions against monospecific sera A and M indicated that these two isolates (No. 15 and 16) belong to the genus Brucella. Genus specific, AMOS (abortus, melitensis, ovis, suis) and Bruce‐ladder multiplex polymerase chain reaction (PCR) assays confirmed the Brucella isolates as either a B. abortus or a B. canis strain. This is the first report of the occurrence of a B. canis infection in cattle in Korea. More survey data are needed to determine whether B. canis is a significant aetiology in the cases of cattle brucellosis in Korea.

Prevalence of colibacillosis in chickens in greater Mymensingh district of Bangladesh

Aim: This study was conducted for determination of the prevalence of colibacillosis in chicken in poultry farms in Mymensingh and Tangail districts. Isolation, identification, and antibiogram profile of Escherichia coli were also performed. Materials and Methods: A total of 25 chickens manifested clinical signs of colibacillosis were collected from five different poultry farms during natural outbreaks. Results: In broiler, the prevalence of colibacillosis was 0.84%, and in layer, prevalence was 0.80%. The prevalence of colibacillosis was 1.0% and 0.5% in 25-30 days old and 31-35 days old broiler, respectively. In case of layer birds, the prevalence was 0.6% in 40-45 days old bird and 1% in 46-50 days old bird. Identity of the E. coli isolate of chicken was confirmed by sugar fermentation, biochemical tests, and polymerase chain reaction assay. Antibiogram profile of E. coli isolate of chicken revealed that it was multidrug resistant (resistant against two antibiotics, such as ampicillin and cefalexin). Conclusion: Data of this study suggest that colibacillosis is prevalent in the study areas which underscore the need of implementation of prevention and control measure against this disease.

Efficacy of strain RB51 vaccine in protecting infection and vertical transmission against Brucella abortus in Sprague-Dawley rats

Immunizing animals in the wild against Brucella (B.) abortus is essential to control bovine brucellosis because cattle can get the disease through close contact with infected wildlife. The aim of this experiment was to evaluate the effectiveness of the B. abortus strain RB51 vaccine in protecting infection as well as vertical transmission in Sprague-Dawley (SD) rats against B. abortus biotype 1. Virgin female SD rats (n = 48) two months of age were divided into two groups: one group (n = 24) received RB51 vaccine intraperitoneally with 3 × 1010 colony forming units (CFU) and the other group (n = 24) was used as non-vaccinated control. Non-vaccinated and RB51-vaccinated rats were challenged with 1.5 × 109 CFU of virulent B. abortus biotype 1 six weeks after vaccination. Three weeks after challenge, all rats were bred. Verification of RB51-vaccine induced protection in SD rats was determined by bacteriological, serological and molecular screening of maternal and fetal tissues at necropsy. The RB51 vaccine elicited 81.25% protection in SD rats against infection with B. abortus biotype 1. Offspring from rats vaccinated with RB51 had a decreased (p < 0.05) prevalence of vertical transmission of B. abortus biotype 1 compared to the offspring from non-vaccinated rats (20.23% and 87.50%, respectively). This is the first report of RB51 vaccination efficacy against the vertical transmission of B. abortus in the SD rat model.

Molecular Detection of Brucella spp. from Milk of Seronegative Cows from Some Selected Area in Bangladesh

Brucellosis is endemic in Bangladesh both in humans and in animals. A number of reasons complicate the diagnosis, as bovine brucellosis can be diagnosed by various serological tests. But the tests have a limitation; when the organism remains intracellular, the disease goes into chronic stage and the antibody titres may decline. The present study was conducted for isolation and detection of Brucella spp. by polymerase chain reaction (PCR) from seronegative cows. A total of 360 dairy cows from three geographical regions were screened serologically by Rose Bengal Plate Test (RBPT) where 24 samples were serologically positive and the rest of the samples were serologically negative. Among the 24 seropositive individuals, 11 were culture positive and 6 were culture positive from serologically negative dairy cows. The overall seroprevalence of brucellosis in cattle was 6.6% and in disease condition a higher prevalence was recorded in abortion (28.07%) followed by infertility (13.33%). To confirm the Brucella spp. in seronegative dairy cattle, the isolates were extracted and PCR was conducted, which produced 905 bp amplicon size of 6 Brucella spp. from milk sample. So, for the detection or eradication of brucellosis, a bacteriological test and a PCR technique should be performed with the serological test of milk.

Male rats transmit Brucella abortus biotype 1 through sexual intercourse

The aim of this study was to evaluate transmission of Brucella abortus biotype 1 via sexual intercourse in rats. Male and female virgin Sprague-Dawley (SD) rats were experimentally infected intraperitoneally with 1×10(9)colony forming units (CFU) of B. abortus biotype 1, a Korean bovine isolate. At 14 days after infection, infected male rats (n=10) were housed with uninfected female rats (n=10) and infected female rats (n=10) were housed with uninfected male rats (n=10) for a period of one month. During this period all uninfected female rats became pregnant and 6 of 10 infected female rats became pregnant. Serum from two out of 10 female uninfected rats had positive reactions in the Rose Bengal Plate Agglutination Test (RBPAT), Tube Agglutination Test (TAT) or the Enzyme-Linked Immunosorbent Assay (ELISA); whereas none of the uninfected male rat had positive reactions in these tests. Using bacteriological culture and AMOS-PCR assay, B. abortus biotype 1 was isolated and identified from two uninfected female rats and all of the uninfected male rats were found negative for B. abortus biotype 1. It was concluded that transmission of B. abortus biotype 1 from infected male to uninfected female rats resulted from sexual intercourse.

Immunoglobulin profiles in acute Brucellosis experimentally induced by Brucella canis in BALB/c mice.

This study evaluated profiles of immunoglobulin (Ig; IgA, IgG, IgG1, and IgG2a) response in experimental brucellosis induced with Brucella canis in BALB/c mice during an 8-week infection period. Six- to 8-week-old BALB/c mice (n = 36) were experimentally infected with 1 × 10(9) CFU of B. canis via the intraperitoneal route. Serial serum samples were collected from the mice at 0, 3, 7, 14, 21, 28, 35, 42, 49, and 56 days after inoculation. The sera were tested by the rapid slide agglutination test (RSAT) and 2-mercaptoethanol-RSAT and indirect enzyme-linked immunosorbent assay. Sera tested positive for B. canis by the RSAT and 2-mercaptoethanol-RSAT beginning from 7 days after inoculation until the end of the experiment. The IgA response was detected at 14 days after infection and reached peak levels at 21 days after infection. The IgG antibody responses were detected at 7 days after infection and reached the peak value at 35 days after infection. Data of our study demonstrated IgG2a-dominant responses over IgG1 during the course of infection (p > 0.05).

Isolation and identification of bacteria from fresh guava (Psidium guajava) sold at local markets in Mymensingh and their antibiogram profile

Aim: The study was conducted for the isolation, identification, and antibiogram of bacteria obtained from fresh guava (Psidium guajava). Materials and Methods: A total of 25 fresh guavas were collected from five markets located in Mymensingh city. Guava samples were cultured onto various selective media such as eosin methylene blue, xylose lysine deoxycholate, thiosulfate-citrate-bile salts-sucrose, blood agar, and mannitol salt agar for the isolation of bacteria. Biochemical tests (dextrose, maltose, lactose, sucrose, mannitol, methyl red, Voges–Proskauer, and indole) were performed to identify the bacteria. Results: Total viable counts of guava were ranged between log 6.56 colony-forming unit (cfu)/ml and 6.62 cfu/ml. A total of 106 bacterial isolates belonged to five genera (Escherichia coli, Salmonella spp., Vibrio spp., Bacillus spp., and Staphylococcus spp.) were identified. Salmonella spp. (23.6%) was the most prevalent, followed by E. coli (22.64%), Bacillus spp. (19.81%), Staphylococcus spp. (17.92%), and Vibrio spp. (16.03%). The results of antibiotic sensitivity test showed that Salmonella spp., Bacillus spp., and E. coli were sensitive to chloramphenicol, ciprofloxacin, and gentamicin and resistant to ampicillin and cephalexin. Vibrio spp. was sensitive to chloramphenicol and gentamicin, intermediately sensitive to ciprofloxacin and ampicillin and resistant to cephalexin. Conclusion: The results of this study indicate that fresh guava contains multidrug-resistant bacteria which might pose a public health risk.