Poultry production plays a vital role in ensuring food and nutritional security in Bangladesh by supplying affordable sources of animal protein, namely, meat and eggs, and generating income for millions. Due to their wide availability, low cost, and absence of religious restrictions, poultry products have become a major source of animal protein in the country. This narrative review examines the profiles of ectoparasites, endoparasites, and haemoparasites commonly found in Bangladeshi poultry, all of which contribute to reduced growth performance and productivity. A comprehensive search of peer-reviewed studies from databases such as Google Scholar, PubMed, and ScienceDirect was conducted to gather data on the prevalence, distribution, and health impact of these parasites. Gastrointestinal parasites, including nematodes, cestodes, trematodes, and coccidian protozoa, are widely reported in poultry populations. Several ectoparasites have also been identified, including lice; three mite species (Dermanyssus gallinae, Knemidocoptes mutans, and Trombicula spp.); one flea species (Echinophaga gallinacea); and two fly species (Simulium spp. and Pseudolynchia canariensis). In addition, three haemoparasites, Plasmodium spp., Haemoproteus spp., and Leucocytozoon spp., have been observed in various poultry species across the country. The prevalence and distribution of these parasites vary by poultry type and geographic region, which are exacerbated by factors such as poor sanitation, inadequate deworming practices, limited public awareness, favorable climatic conditions, and the presence of intermediate and susceptible hosts. By addressing these challenges, Bangladesh can significantly reduce the burden of poultry parasites, improve overall veterinary and public health outcomes, and ensure sustainable development.

Linguatulosis, caused by Linguatula serrata, commonly known as the tongue worm, primarily affects food animals and carnivores and poses a potential zoonotic risk. This systematic review and meta-analysis aimed to evaluate the global prevalence of L. serrata in these hosts. A comprehensive search identified 55 studies involving 36,242 samples from food animals and 1530 samples from carnivores across four continents. The results indicated significant variability in prevalence rates, with food animals showing a pooled prevalence of 19.1 %, and carnivores exhibiting a higher pooled prevalence of 35.5 %. The prevalence in food animals varied across species, with goats having the highest prevalence at 32.6 %, followed by camels (19.3 %), cattle (15.8 %), sheep (13.6 %), and buffalo (10.6 %). The analysis showed substantial heterogeneity (I² = 98.9 % for food animals and I² = 96.6 % for carnivores), which was influenced by factors such as host species, diagnostic methods, and sample types. Meta-regression analysis showed that host species was a significant moderator of prevalence. Sensitivity analysis and bias tests confirmed the robustness of the findings, with consistent pooled prevalence estimates and no significant publication bias. Geographic analysis showed regional differences, with particularly high prevalence rates in Bangladesh, India, Iran, and Nigeria. The study also observed temporal fluctuations, with peak prevalence recorded during 2016-2020 for food animals and 2006-2010 for carnivores. These findings emphasize the need for targeted surveillance and control strategies, particularly in regions with high transmission risks, and the importance of standardized diagnostic methods to reduce variability in future studies.

Cryptosporidium spp. and Giardia duodenalis are intestinal protozoan parasites of zoonotic concern that cause gastrointestinal diseases in humans and various animals, including cats and dogs. This study investigates the prevalence, risk factors, and genetic diversity of Cryptosporidium spp. and G. duodenalis in domestic cats and dogs in Bangladesh to assess their zoonotic potential. Fecal samples were collected from 197 cats and 120 dogs in Dhaka and Gazipur metropolitan areas. We performed nested PCR targeting the small subunit ribosomal RNA (SSU rRNA) gene for Cryptosporidium and the β-giardin (bg), glutamate dehydrogenase (gdh), and triosephosphate isomerase (tpi) genes for G. duodenalis, followed by nucleotide sequencing and analysis. The overall prevalence of Cryptosporidium was 8.1 % in cats and 4.2 % in dogs, whereas G. duodenalis was more common, detected in 29.9 % of cats and 25 % of dogs. Among examined variables, only sex and food types were significantly associated with G. duodenalis infection in dogs and cats, respectively. Molecular analysis identified three Cryptosporidium spp. in cats, including C. felis (81.3 %), C. baileyi (12.5 %), and C. canis (6.3 %), whereas 100 % of Cryptosporidium isolates from dogs were identified as C. canis. Multilocus genotyping of G. duodenalis revealed both host-adapted and zoonotic assemblages. Assemblage A predominated in both cats and dogs, followed by F and C in cats and C and D in dogs, with mixed infections observed in both hosts. The detection of zoonotic species and assemblages underscores the potential role of cats and dogs as reservoirs for human infection. These findings highlight the importance of monitoring intestinal protozoa in companion animals and promoting appropriate hygiene practices within a One Health framework.

This review examines molecular techniques for the detection and genotyping of Toxoplasma gondii across livestock, wildlife, companion animals (including cats) and humans to evaluate their diagnostic utility and epidemiological relevance globally. Detection techniques, including conventional PCR, nested PCR, real-time PCR, and LAMP, are preferred for their high sensitivity and specificity. Advanced methods, including PCR-RFLP, microsatellite analysis, and MLST, are utilized to identify T. gondii genotypes. Molecular analyses revealed considerable genetic diversity, including clonal Types I, II, and III, and atypical recombinant genotypes. Type III predominated in Asia and North America, Type II in Europe and Australia, and atypical genotypes in South America and Africa. Type II was most common among humans and cattle, while genotypes in cats, pigs, sheep, and wildlife varied by geographical region. Integrating sensitive detection with high-resolution genotyping strengthens outbreak investigation and surveillance. However, methodological inconsistencies between PCR-RFLP and MLST hinder global comparisons. Standardizing genotyping approaches is critical for tracking emerging recombinant strains and improving toxoplasmosis control strategies worldwide.

Nipah virus (NiV) infection is a highly fatal zoonotic disease and remains a major public health concern in Bangladesh. This narrative review comprehensively examines the epidemiology, outbreak pattern, transmission dynamics, clinical manifestations, ecological drivers, public health interventions, surveillance systems, therapeutic progress, and vaccine development related to NiV infection in Bangladesh. The review was conducted through a comprehensive analysis of published literature and relevant reports from 2001 to February 2026, retrieved from PubMed, Scopus, and Google Scholar. During this period, Bangladesh reported 348 confirmed NiV cases across 35 districts, with 250 deaths and an overall case fatality rate of 71.84%. Outbreaks were concentrated mainly in the central and northwestern regions, commonly referred to as the “Nipah belt.” The principal route of transmission was consumption of raw date palm sap contaminated by greater Indian fruit bat (Pteropus medius), while person-to-person transmission through close contact with infected individuals also played an important role. Clinical features were dominated by fever, unconsciousness, respiratory distress, headache, vomiting, and other neurological symptoms. Seasonal outbreaks were strongly associated with winter sap collection, bat feeding behavior, environmental conditions, and cultural practices. Although bamboo skirts, awareness campaigns, boiling of sap, and hospital-based surveillance have contributed to prevention efforts, sustained community adoption remains limited. Bangladesh still lacks approved vaccines, specific antiviral therapy, rapid point-of-care diagnostics, and advanced biosafety infrastructure. Expanding surveillance, improving early diagnosis, implementing ecological interventions, and advancing vaccine and therapeutic research are essential to reduce future spillover and human-to-human transmission.

Toxoplasma gondii is a globally prevalent zoonotic protozoan parasite with a complex life cycle, using felids as definitive hosts and various warm-blooded animals as intermediate hosts. This study aimed to assess the sero-molecular prevalence and risk factors of T. gondii infection in domestic cats in the Dhaka Metropolitan Area, Bangladesh. Blood and fecal samples from 184 cats were collected and analyzed using both enzyme-linked immunosorbent assay (ELISA) and conventional polymerase chain reaction (PCR) targeting the REP-529 gene. The seroprevalence of T. gondii was determined as 9.78% (18/184), while molecular analysis detected a slightly lower prevalence of 8.15% (15/184) among the sampled cats. Several host- and management-related factors were significantly associated with T. gondii infection in cats. ELISA positivity was significantly higher in non-dewormed cats, those with outdoor access, and those defecating outdoors, while PCR positivity was significantly associated with outdoor access and outdoor defecation. Multivariable logistic regression revealed that age, deworming status, and outdoor access were significant risk factors based on ELISA. In contrast, outdoor access alone was identified as a risk factor by PCR detection. The results indicate that T. gondii infection is common among domestic cats in Bangladesh, posing a potential risk of zoonotic transmission to humans. These findings highlight the importance of raising cat owners' awareness, enhancing public health education, and promoting preventive veterinary care to reduce the transmission of T. gondii between cats and humans.

Gastrointestinal (GI) parasitism, a major concern in pig farming, causes economic losses and poses zoonotic risks. This study aimed to investigate the prevalence and risk factors of GI parasites in domestic pigs in the Chattogram Hill Tracts (CHT) of Bangladesh, as well as assess their potential zoonotic risk to the region’s ethnic communities. A cross-sectional study was conducted in Rangamati, Khagrachari, and Bandarban districts, where 488 fresh fecal samples were collected and analyzed using direct smear, sedimentation, and flotation techniques to identify parasite species. The overall prevalence of GI parasites was 82.5

Parasitic zoonoses pose a significant public health threat in Bangladesh, yet a comprehensive synthesis of available evidence has been lacking. This review compiled peer-reviewed studies published between 2000 and 2025 to summarize the epidemiology, transmission dynamics, risk factors, and control strategies for major zoonotic parasites affecting humans, livestock, pets, and wildlife across diverse ecological settings in Bangladesh. Among protozoan parasites, Cryptosporidium spp. were detected in 2.77–9.20% of human samples and 5.00–15.70% of cattle samples, with three novel zoonotic subtypes recently identified in shared human-calf environments. Giardia duodenalis was found across 12.71–80.89% of human samples and 5.70–22.00% of calves, with assemblages A and B predominating, while Toxoplasma gondii was detected in aborted fetuses of sheep and goats, underscoring its reproductive impact in small ruminants. Fascioliasis prevalence in ruminants was up to 66.14%, with hybrid Fasciola species documented in flood-prone lowlands. Strongyloides stercoralis had a prevalence of 23.10–25.00% in humans; schistosomiasis affected 1.50–47.50% of surveyed animals; and human cercarial dermatitis was reported in 53.30% of river-basin communities. Soil-transmitted helminths persisted despite sanitation improvements, and vector-borne parasites transmitted by ticks, fleas, and sandflies were documented across multiple host species. Parasite diversity was highest in the Dhaka and Chattogram divisions. Key risk factors included seasonal flooding, poor sanitation, open defecation, close human-livestock contact, inadequate deworming, and limited diagnostic capacity. Collectively, these findings reveal critical surveillance gaps and underscore the urgent need for an integrated One Health approach combining molecular diagnostics, targeted deworming, vector control, and intersectoral coordination to reduce the burden of parasitic zoonoses in Bangladesh. Data availability Boolean search strings for PubMed are available in Supplementary file 1.

Enterocytozoon bieneusi, a microsporidian fungus, and Blastocystis, a protist, are zoonotic enteric microbes causing gastrointestinal disorders in humans and various animals, including cats and dogs. This study aimed to determine the molecular prevalence, associated risk factors, genetic diversity, and zoonotic potential of these pathogens in feline and canine populations in Dhaka and Gazipur metropolitan areas. Fecal samples were collected from 197 cats and 120 dogs and analyzed using nested PCR targeting the internal transcribed spacer (ITS) region of the ribosomal RNA (rRNA) gene for E. bieneusi and a conventional PCR targeting the small subunit ribosomal (SSU) rRNA gene for Blastocystis. The overall prevalence of E. bieneusi was 9.1% in cats and 11.7% in dogs. Blastocystis was detected in 3.6% of cats and 10.0% of dogs, with feline infection occurring exclusively in kittens (<1 year). Multivariable analysis identified female sex and young age as the sole significant risk factors for E. bieneusi in dogs and for Blastocystis in cats, respectively. Molecular characterization identified four E. bieneusi genotypes (D, Henan V, BANEB17, and BANEB4) in cats and seven genotypes (PtEb IX, D, EbpC, Type IV, BANEB14, BANEB15, and BANEB16) in dogs. Phylogenetic grouping and sequence comparison confirmed genetic identity between several isolates and genotypes circulating in Bangladeshi children. Among these, four genotypes (BANEB14, BANEB15, BANEB16, and BANEB17) were novel, and the majority exhibited zoonotic potential. Similarly, six Blastocystis subtypes (ST1, ST3, ST4, ST6, ST23, and ST44) were identified in both cats and dogs, with ST1, ST3, and ST4 recognized for their zoonotic potential. These findings suggest a potential role for companion animals in zoonotic transmission, necessitating integrated One Health surveillance strategies.

Molecular surveillance of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli in environmental reservoirs is essential for understanding antimicrobial resistance (AMR) transmission within the One Health framework. This study aimed to characterize the genetic diversity and phylogenetic relationships of blaCTX-M and blaTEM genes in ESBL-producing E. coli isolated from hospital wastewater in Manila and Quezon City, Philippines. Seventeen isolates carrying blaCTX-M-1, blaCTX-M-9, and blaTEM-1 genes, confirmed by multiplex PCR, were subjected to DNA sequencing and phylogenetic analysis alongside global reference strains. Phylogenetic analysis of the blaCTX-M gene sequences revealed two distinct clusters: six blaCTX-M-15 variants clustered within the CTX-M-1 clade, showing close relatedness to strains from Thailand, Iran, and neighboring Southeast Asian clinical and environmental samples, while two blaCTX-M-27 clustered within the CTX-M-9 group, closely related to isolates from India, Australia, and Spain. All blaTEM-1 gene sequences aligned with globally disseminated TEM-1 references. The co-occurrence of multiple ESBL gene variants in individual effluent samples underscores active horizontal gene transfer facilitated by mobile genetic elements in wastewater environments. These findings reveal substantial genetic diversity of ESBL determinants and demonstrate the convergence of clinical and environmental AMR reservoirs through hospital effluents. Incorporating genetic surveillance of hospital wastewater into national AMR action plans can enhance detection of emerging resistance variants, inform risk assessment, and guide targeted interventions to mitigate environmental dissemination. Future work should integrate whole-genome sequencing to elucidate plasmid dynamics and resistance gene mobilization mechanisms, advancing One Health strategies to curb the AMR threat.

Cryptosporidium and Giardia are significant causes of gastrointestinal diseases in humans and animals worldwide, especially in pigs. This study investigated the molecular occurrence, genetic diversity, and zoonotic potential of Cryptosporidium spp. and Giardia duodenalis in domestic pigs in the Chattogram Hill Tracts (CHT), Bangladesh. A total of 408 fecal samples were collected from Rangamati, Khagrachari, and Bandarban districts and examined using nested PCR, targeting the SSU rRNA gene for Cryptosporidium and the β-giardin (bg), glutamate dehydrogenase (gdh), and triosephosphate isomerase (tpi) genes for G. duodenalis. Nucleotide sequencing and phylogenetic analysis were conducted for molecular characterization. The prevalence of Cryptosporidium was 3.43

Gastrointestinal (GI) parasites in companion animals pose significant veterinary and public health challenges, especially in densely populated urban areas anddeveloping regions such as Dhaka, Bangladesh. Thus, this study was designed to determine the prevalence of GI parasitic infections in pet dogsand cats, identify the parasite species, and analyze the associated risk factors. Across-sectional survey was conducted from January to June 2024, involving 120 dogs and 197 cats in Dhaka City. Fresh fecal samples were collected from the dogs and cats and analyzed for parasitic eggs, cysts, and oocysts using microscopic methods, including direct smear, fecal flotation, and sedimentation techniques. The results revealed an overall parasitic prevalence of 63.33 % in dogs and 58.37 % in cats, with a total of 15 parasitic species identified in both pets. The presence of both shared and host-specific parasites highlights the risks of environmental contamination, with Toxocara spp. being the most commonly identified parasite in dogs and cats. Among the parasites, Alaria spp., Ancylostoma spp., Ascaris spp., Balantidium coli, Capillaria spp., Entamoeba coli, Schistosoma spp., Spirometra spp., Strongyloides spp., Taenia spp., Toxocara canis/cati, Trichuris spp. can infect humans and have zoonotic transmission potential. The key risk factors identified for dogs include the absence of deworming, male sex, age under one year,and hunting behavior. For cats, the primary significant factors were the absence of deworming and being crossbred. The findings highlight the importance of regular deworming, proper pet management, and strengthened public health measures to mitigate veterinary and public health risks. This study can aid veterinarians and public health authorities in formulating strategies to control gastrointestinal parasitic infections while encouraging pet owners to adopt responsible pet care practices.

Heat stress (HS) is a concerning issue for the health and performance of cattle and is manifested by various behavioral and physiological changes. HS leads to a decrease in dry matter intake, rumen activity, growth performance, and milk yield in animals. Extreme HS for at least three consecutive days increases the risk of death. HS also causes a decline in the ruminal microbiota, pH, and acetate concentration, and an increase in lactate-producing bacteria and the lactate concentration. Reduced feed and water intake lead to a decline in milk production. The milk protein and casein content go down due to insulin resistance and apoptosis of mammary epithelial cells caused by oxidative stress, but urea concentrations become higher. Milk’s metabolomes, glycine, proline, isoleucine, and phosphocreatine have been found to decrease, while citrate, acetone, and β-hydroxybutyric acid concentrations evidently increase. Blood cell count, glucose, protein, and IgG concentrations also fall due to HS. Short estrus, impaired follicular development, poor quality oocytes and spermatozoa, a reduced conception rate, and decreased semen quality have become very common. For all of this, the present study demonstrates the various effects of HS on cattle health, production, and reproduction.

Globally poultry production is increasing to fulfill the protein requirements for human consumption. Poultry waste from farms might contaminate adjacent environments and agricultural products grown in lands that used poultry manure as a soil organic fertilizer. In order to determine the spread of poultry waste bacteria to adjacent water bodies, soils, and agricultural products, Escherichia coli (E. coli) were isolated from poultry fecal wastes as well as from nearby water bodies, soils, and agricultural products grown in lands that used poultry wastes. E. coli of poultry manure and poultry environment (soils, water, and vegetables) were isolated and confirmed by culturing and amplification of malK gene of E. coli by polymerase chain reaction (PCR). Contamination of the nearby environment by poultry waste E. coli was also determined by VT1 (stx1) gene of E. coli. Subsequently, gene sequencing of the positive isolates of E. coli and phylogenetic trees was developed to find out evolutionary dynamics of the poultry environment E. coli. The overall prevalence of E. coli in the poultry environment was 61.02%. E. coli were detected in the manure of all broiler, layer, and Sonali types of poultry farms. E. coli also detected in both chicks and adult layer farms during all the seasons by malK gene. The VT1 (stx1) gene of E. coli was not detected in any of the samples. Contamination by poultry fecal E. coli to adjacent water bodies, soils, and vegetables grown on soils that used poultry waste as manure were also found. Phylogenetic tree denotes there were genetic similarities of poultry manure E. coli of Gazipur, Bangladesh to global isolates of E. coli from livestock, their environment, and humans. These findings will be crucial to undertake measures to limit spread of poultry manure E. coli to the surrounding environment as well as controlling zoonoses.

Blastocystis is a single-celled intestinal protist found worldwide in humans and animals, including pigs, and can cause gastrointestinal disorders. It can hinder pig production and pose a potential zoonotic risk. The parasite exhibits considerable genetic diversity and is currently classified into 44 recognized subtypes (STs). Of these, nine STs have been identified in pigs, eight of which are considered zoonotic. This study aimed to investigate the molecular prevalence, genetic diversity, and zoonotic potential of Blastocystis in pigs raised by the ethnic communities in the Chattogram Hill Tracts of Bangladesh. A total of 408 fresh pig fecal samples were collected from the three hill districts, Rangamati, Khagrachhari, and Bandarban, and analyzed using polymerase chain reaction (PCR) targeting the small subunit ribosomal RNA (SSU rRNA) gene. Molecular analysis revealed an overall prevalence of Blastocystis at 20.83% (85/408). Although prevalence varied across several variables, multivariable logistic regression identified location as the only significant risk factor, with pigs from Khagrachhari being almost 18 times more likely to be infected with Blastocystis compared to those from Bandarban. Among the 85 positive samples, three STs were identified: ST1, ST3, and ST5. The predominant subtype was ST5, which accounted for 92.92% of cases. Notably, all detected STs were zoonotic, underscoring the potential risk of cross-species transmission. This study presents the first report of Blastocystis infection in domestic pigs in Bangladesh and, given its high prevalence, low genetic diversity, and zoonotic potential, underscores the need for further research on its epidemiology, genetic makeup, and transmission across the country.

Toxoplasmosis, caused by Toxoplasma gondii, is a zoonotic disease that affects a wide range of warm-blooded animals, including humans. The parasite undergoes both sexual and asexual reproduction in intermediate hosts (humans and animals) and definitive hosts (cats). Transmission in humans occurs through consuming oocyst-contaminated water, fruits, vegetables, and raw or undercooked meats. In Bangladesh, several factors contribute to an increased risk of contracting toxoplasmosis. The parasite is reported to cause diseases among livestock such as goats and sheep in this country, and it has also been associated with some human illnesses. Toxoplasmosis prevalence varies significantly worldwide, with developing countries like Bangladesh experiencing higher rates. Diagnostic methods include both conventional non-DNA-based tests and molecular detection techniques, while treatment options involve using antiparasitic drugs like sulfadiazine and pyrimethamine. To control toxoplasmosis, essential steps include improving sanitation, promoting safe food handling, and educating the public about risks related to cat ownership and undercooked meat consumption. Implementing prenatal screening and treatment is also important. With the growing popularity of pet ownership in urban areas, it becomes essential to emphasize the veterinary and public health significance of toxoplasmosis in Bangladesh. This article comprehensively reviews various aspects of toxoplasmosis, with a specific focus on the situation in Bangladesh.

Background: Antimicrobial resistance (AMR) poses a significant global threat within the one-health framework. This study aimed to assess the aggregated prevalence of common pathogenic bacteria, and their AMR profiles including resistant genes in livestock and poultry across South Asia from 2014 to 2023. Methods: For data analysis and visualization, metafor, metareg, and other related packages in R programming language were utilized. A random-effect model was applied for pooled prevalence to account for substantial heterogeneity. Meta-regression and sensitivity analysis were conducted to assess and address heterogeneity. Regional AMR patterns and a heat map displaying resistant genes were visualized, as well. Results: The pooled prevalence of Escherichia coli , Salmonella spp., and Staphylococcus spp. in South Asian livestock and poultry stood at 74%, 37%, and 48%, respectively. Noteworthy variations in antibiotic resistance were observed, with E. coli displaying the lowest resistance to azithromycin (6.7%) and Salmonella to ceftriaxone (5.89%). Erythromycin resistance reached its apex for both E. coli (89%) and Salmonella (94.04%). Staphylococcus showed a moderate range of resistance, with penicillin registering the lowest (20.37%) and gentamicin the highest (49.55%). Bangladesh exhibited the highest regional prevalence of both pathogens and AMR. The predominant resistant genes were tetA , bla TEM , bla CTX , mcr1 , and sul1 . Conclusions: The findings reveal a concerning surge in AMR in South Asia, particularly within the livestock and poultry sector. Monitoring AMR patterns, devising effective antibiotic regimens, and enhancing food safety and public awareness in the One Health approach can mitigate both pathogen prevalence and AMR rate in this region.

Cryptosporidium is a gastro-intestinal protozoan parasite that has been found to infect both humans and livestock. This study investigated the parasite in 998 fecal samples from Bangladeshi children (n = 299) and calves (n = 699) to determine its prevalence, genetic variation, and zoonotic importance. The nested PCR and sequencing of the SSU rRNA gene in the samples showed a Cryptosporidium infection rate of 2.3% (7/299) in children and 15.7% (110/699) in calves. Statistical analysis revealed insignificant variations in Cryptosporidium infections among children across age, gender, and study area, while in calves, the infection rate significantly differed based on location and breed. Genotyping of seven human isolates of Cryptosporidium confirmed C. hominis (n = 5) and C. parvum (n = 2). After characterizing 110 Cryptosporidium isolates from calves, C. andersoni (n = 55), C. ryanae (n = 29), C. bovis (n = 14), C. parvum (n = 10), C. ubiquitum (n = 1), and C. occultus (n = 1) were identified. Cryptosporidium hominis and C. parvum-positive samples were further subjected to nested PCR and sequencing of the glycoprotein 60 (gp60) gene for subtyping. Four C. hominis subtypes (IaA19R3, IaA23R3, IbA9G3, and IdA15G1) and one C. parvum subtype (IIdA15G1) were observed. In conclusion, Cryptosporidium was prevalent in calves but less common in children in the study locations, and the presence of zoonotic Cryptosporidium species and subtypes in calves raises concerns regarding zoonotic transmission to humans.