The nesting and breeding ecology of the Great Egret was studied in north and northeastern Bangladesh from 2017 to 2023. Out of 199 colony sites, 111 (55.78 %) were actively breeding, 38 (19.10 %) served as night roosts, and 50 (25.12 %) were abandoned. The active breeding colony sites covered a total of 92.12 hectares, with the majority situated on private land (89.92 ha) and only a small portion on government land (2.20 ha). The highest number of active breeding colonies occurred in Naogaon (n = 22), followed by Sylhet (n = 14) and Habiganj (n = 9), while Bogura, Natore, Rajshahi, and Jamalpur each had only one (n = 1). Of the 5,755 nests counted, the largest proportion was in Naogaon (20.94%), followed by Netrokona (17.74%) and Sylhet (7.91%), with the lowest in Bogura (0.21%). Active breeding colonies were predominantly in paddy field-dominated habitats (71.17%, n = 79), with smaller proportions in wetlands (9.91%, n = 11), mixed agriculture (9.01%, n = 10), tea gardens (4.50%, n = 5), orchards (2.70%, n = 3), and homestead areas (2.70%, n = 3). Breeding occurred from April to September, with colony sizes ranging from 2 to 302 nests. Nesting occurred on 1,258 plants across 34 species, with a preference for Bambusa spp. (40.31%), followed by Mangifera indica (15.57%), Swietenia mahagoni (8.98%), and Tamarindus indica (8.06%); the average nesting height was 10.39 ± 2.41 m (range 5.2-16.41 m, n = 1,258). Clutches averaged 2-4 eggs (mean 2.78 ± 0.71, n = 18), laid over 4-9 days. The incubation period lasted 23–28 days, chicks fledged after 40-55 days, and overall breeding success was 74%. Bangladesh J. Zool. 53(3): 373-388, 2025

Helicobacter pylori is an extensively prevalent gastrointestinal pathogen that continues to pose a noteworthy public health challenge worldwide, predominantly in low and middle-income countries where overcrowding, poor hygiene, and limited access to healthcare persist common. The current study was undertaken to address this knowledge paucity by evaluating the prevalence of H. pylori infection during early pregnancy and reconnoitering its potential health implications among women residing in an urban slum in Dhaka. It was a descriptive, hospital-based cross-sectional study, conducted between August 2017 and April 2018. A total of 45 women, permanent residents of Kamrangir Char in their early trimester (9 to 16 weeks) of pregnancy, were enrolled after securing informed consent from Maternal and Child Health Training Institute (MCHTI), Azimpur. Stool samples were collected from each participant and analyzed for the detection of H. pylori antigen using a clinically authorized enzyme-linked immunosorbent assay (ELISA). Laboratory procedures, data entry, and statistical analyses, were carried out at the Nutrition, Immunology, and Toxicology Laboratory of International Centre for diarrheal disease research, Bangladesh icddr,b in accordance with standardized quality-control protocols. The results revealed a high prevalence of H. pylori infection, with 75.6% of the participants testing positive. Supplementary stratification of the data by maternal age and gestational age did not demonstrate any statistically significant variation in infection prevalence. The socio-demographic profile of the study population reflected widespread poverty, low levels of formal education, and limited dietary diversity factors that collectively increase susceptibility to chronic infections and nutritional deficiencies during pregnancy. Given the pathogen’s potential to impair nutrient absorption and contribute to poor maternal and fetal outcomes, the integration of H. pylori screening, targeted nutritional interventions, and health education into routine antenatal care is strongly recommended for high-risk populations in similar settings. Bangladesh J. Zool. 53(3): 297-309, 2025

A study was conducted on the physico-chemical parameters in the Buriganga River at Wise Ghat and Postogola Bridge, Dhaka, Bangladesh, on a monthly basis from October 2023 to September 2024. The purpose of this study is to evaluate the present water quality status based on six selected physico-chemical properties of water including water temperature, transparency, total dissolved solids (TDS), electrical conductivity (EC), pH and dissolved oxygen (DO). Minimum average temperature was observed 19.4 °C in January while maximum average temperature was 33.6 °C in November. The Minimum and the maximum value of average transparency of the river water was determined as 21.8 cm in May and 52.6 cm in October, respectively. Minimum average TDS was 85 ppm in July and maximum average TDS was 403 ppm in May. Minimum average EC was 150 µS/cm in October and maximum average was 589.5 µS/cm in May. pH of the water found more stable round the year which ranged from 7.4 to 7.8 and annual mean pH value was 7.62. DO of the water showed a greater fluctuation, which ranged from 0.9 ppm in May to 7.25 ppm in September. Some parameters were not within the standard limit for aquatic life. A regular monitoring system could be developed to prevent further deterioration of water condition and restoration of the ecosystem of the Buriganga River. Bangladesh J. Zool. 53(3): 285-296, 2025

Abstract not Available Bangladesh J. Zool. 53(1): 125-129, 2025

The Asian house gecko (Hemidactylus frenatus) is a unique species among lizards, commonly found in human habitats and often regarded as a pest. Like all vertebrates, these geckos are susceptible to parasites. In this investigation, a total of 54 H. frenatus specimens were collected from randomly selected households in various locations throughout Dhaka city to examine parasitic infections. The study's results revealed that 61.11% of the geckos were infected with endoparasites. The infection rate for female geckos (63.64%) was higher than that for males (59.38%). A total of 61 parasites were collected from different organs including the body cavity, stomach, intestine, and lungs of the house geckos. Four species of parasites were identified, belonging to the groups trematode (Ganeo kumaonensis), nematoda (Strongyloides cruzi and Neopharyngodon gecko), and pentastomida (Raillietiella frenatus). Notably, the pentastomid Raillietiella frenatus had not been previously recorded in H. frenatus in Bangladesh. The prevalence of the identified parasites was as follows: Ganeo kumaonensis (9.26%), Strongyloides cruzi (7.41%), Neopharyngodon gecko (37.04%), and Raillietiella frenatus (18.52%). Among these, the nematode exhibited the highest prevalence at 44.44%, while the trematode showed the lowest at 9.26%. A significant number of parasites were also collected from the stomach, accounting for 27.78% of the total. Additionally, when examining various length groups, those geckos measuring 9.5-10.49 cm in length showed a higher susceptibility to parasitic infections (88.23%) compared to other length groups. Similarly, in different weight groups, geckos weighting 2.5-3.49 grams were found to have a higher susceptibility to parasitic infections (78.12%). Furthermore, a positive correlation was observed between the host's weight and the parasite burden. The significance of the current study lies in identifying the parasites that infect this unique species within the study area. Bangladesh J. Zool. 53(1): 57-66, 2025

Abstract not available Bangladesh J. Zool. 53(1): 01-02, 2025

Abstract not available Bangladesh J. Zool. 52(3): 341-348, 2024

Histopathological alterations in the selected organs of a freshwater fish Oreochromis niloticus (L.), exposed to sub lethal concentration (17.5 ppm) of cadmium chloride (CdCl2), were studied at laboratory conditions. Static bioassay test was carried out to determine the sub lethal concentration. The changes in gill, liver, kidney, stomach and intestine of the fish were observed after 7 and 30 days exposure. The degenerative changes exhibited in fish organs were more severe and pronounced at long term exposure than that of at short term. The histopathological changes observed in the gills were fusion of secondary lamellae due to hyperplasia and hypertrophy, lifting and rupture of lamellar epithelium, oedema of primary lamellar tip, necrosis, damage of pillar cell system, congestion in blood vessels and haemorrhagic gill rays. Changes in the liver included disruption of cords, highly chromatic and irregular shaped shrunken hepatocytes, pyknotic nuclei, rupture and loss of cell boundaries, congestion in blood vessels and sinusoid, and presence of yellow brown bodies. Degeneration of tubular epithelium, tubular lumen with cellular debris, necrotic and swollen glomeruli, and haemopoietic tissue degeneration were marked in the kidney of exposed fish. Stomach tissues revealed rupture and separation of mucosal epithelium, swollen epithelial cells, degeneration of gastric gland cells, scattered blood cells all over the tissue and necrosis in the mucosal epithelium and lamina propria. In intestine, disintegration and rupture in mucosal epithelium, sloughing off epithelial and mucous cells, blood congestion in lamina propria, increased goblet cells, etc., were observed during the present study. Bangladesh J. Zool. 52(2): 237-251, 2024

Abstract not available Bangladesh J. Zool. 52(2): 271-275, 2024

The flower shape, size and color preferences of four bee species belonging to the family Apidae was observed. The observed species were Apis cerana Fabricius, Apis dorsata Fabricius, Apis florea Fabricius, and Xylocopa aestuans Linnaeus. The bees were observed and collected from two areas of Dhaka city- Curzon Hall and Ramna Park from February 2022 to December 2022. During the study period it was observed that the abundance of A. florea was the highest (about 35.18% of the total population) and X. aestuans was the least (about 10.26% of the total population). Preference over a particular size was an important attribute among pollinators. Flowers with mean diameter greater than 50 mm (Dahlia sp., Couroupita guianensis, Tagetes sp. Calendula officinalis, Mesua ferrea) were more visited by the pollinators. Flowers of different shapes were examined in the study and pollinators showed different preferences for different shaped flower. A. cerana mostly preferred rounded and rotate shaped flowers (Dahlia sp. 45% and C. sulphureus 41.16%). A.florea had a preference towards the star shaped flower (L.indica, 69.39%) followed by globe shaped flower (Tagetes sp., 50.70%). A. dorsata had a choice over trumpet shaped flower (Tecoma stans, 35.5%), followed by rounded shaped flower (Dahlia sp. 22%). X. aestuans had preferred orchid shaped flower the most (Bauhinia sp., 30.45%) followed by cruciate shaped flower (M. ferrea, 22.91%). Preference for any particular color was also examined in the study. Among them, A. cerana preferred the red color most (about 45% relative abundance in Dahlia sp.) followed by the color orange (about 41.16% relative abundance in C. sulphureus). A. dorsata preferred the yellow color the most (35.5% relative abundance in T. stans) followed by the color red (22% in Dahlia sp.). A. florea had a preference for color pink (69.39% in L. indica and 46.45% in C. guianensis) followed by the color orange (Tagetes sp., 51.61%). X. aestuans preferred the purple color most in the study (30.45% in Bauhinia sp.). The correlation between proboscis length of pollinators and different floral parameters of flowers were also investigated. The results showed that those parameters were not significantly correlated. Bangladesh J. Zool. 52(1): 27-37, 2024