Comparison of the first time detected Oesophagostomum asperum with Oesophagostomum columbianum in sheep and goats in Bangladesh based on the trinity: Morphology, morphometry and genetic diversity.

Oesophagostomum spp. (Family: Chabertiidae) is keeping a low profile in terms of severity in Bangladesh while maintaining economic loss through disguise within sheep and goats. The study was performed to identify prevalence, confirmation of species through morphology and morphometry followed by phylogeny using ITS2 and COX1 genes. In total 384 slaughterhouse-sourced small and large intestines were pooled from Mymensingh, Kishoreganj, Netrokona, Sherpur and Tangail districts of Mymensingh division. Followed by isolation, O. columbianum and O. asperum were identified following their key morphological features. Notably, O. asperum was first time detected in Bangladesh. The overall prevalence of Oesophagostomum spp. was found 60.93%. The prevalence of O. columbianum (64.95%) was almost double than that of O. asperum (35.04%). Among several characters, only the distance between anus to tail tip showed a significant morphological disparity in female. The Neighbor-joining (NJ) phylogenic trees based on ITS2 and COX1 genes confirmed the study species. The first time identified O. asperum along with morphometry and phylogeny will add value to the fact that nematodes are invisibly present with high prevalence in this country. This study will help to draw specific attention to command a practical control strategy for intervening in economic loss.

Ascaridia galli, a common nematode in semiscavenging indigenous chickens in Bangladesh: epidemiology, genetic diversity, pathobiology, ex vivo culture, and anthelmintic efficacy.

Ascaridia galli is the most common nematode in chickens. Ascaridia galli is highly prevalent in chickens reared in scavenging or semiscavenging systems. Here, we studied the epidemiology, pathology, genetic diversity, ex vivo culture protocol and anthelmintic sensitivity of A. galli prevalent in indigenous chickens in Bangladesh. Through morphological study and molecular analyses, the isolated worms were confirmed as A. galli. Of the chickens examined, 45.6% (178 out of 390) were found infected. The male and young chickens were significantly (P < 0.05) more prone to A. galli infection. Prevalence of the infection was significantly (P < 0.05) lower in the summer season. In heavy infections, A. galli blocked the small intestine. Marked inflammation, increased mucus production and petechial hemorrhages were evident in the small intestine, particularly in the duodenum. Also, there were desquamation and adhesion of the mucosal villi; degeneration, necrosis of the epithelial cells and goblet cell hyperplasia. The mucosal layer was infiltrated mainly with eosinophils and heterophils. We developed a hen egg white-based long-term ex vivo culture protocol which supported the survival and reproduction of A. galli for more than a week. Levamisole (LEV) and ivermectin (IVM) efficiently killed A. galli. However, albendazole (ABZ), mebendazole (MBZ), and piperazine (PPZ) did not kill the worms even at 120 µg/mL and 1mg/mL concentrations, respectively. Taken together, our results suggest that A. galli is highly prevalent in semiscavenging chickens in Bangladesh. Ascaridia galli can be easily maintained ex vivo in egg white supplemented M199 medium. LEV and IVM, but not ABZ, MBZ and PPZ, can be used for treating and controlling A. galli infections in chickens.

Ascaridia galli infection in chicken: Pathobiology and immunological orchestra.

BACKGROUND: Ascaridia galli is the largest gut-dwelling helminth of chickens, which confers adverse effects on meat and egg production; thus, on the animal protein supply and the economy. Both adult and immature parasites affect gut health, but larval stages play a major role in pathology. AIMS: Here, we present immunology and pathology of A. galli in chickens. MATERIALS AND METHODS: Literatures were surveyed through online platforms such as PubMed, Google Scholar and Researchgate. RESULTS: The larvae cause excessive mucus production, damage to the intestinal gland, hemorrhage, anemia, diarrhea, and malnutrition. The adult worms can cause death by intestinal obstruction and intussusception. Although both cellular and humoral immunity are involved in fighting against ascariasis, the role of naturally acquired immunity is poorly defined. In cellular immunity, Th-2 cytokines (IL-4, IL-5, IL-9, and IL-13), goblet cells (mucin), gut-associated lymphoid tissues, CD8α+ intraepithelial cells, TCRγδ + T cells, and TGF-ß4 form a protective band. Type 2 immunity provides protection by forming a network of endogenous damage-associated molecular patterns, chitin, and parasitic antigens. Among antibodies, IgY is the most prominent in chickens and provides temporary humoral protection. During parasitic infection, infiltration of various immune cells is evident, especially in the intestinal epithelium, lamina propria, and crypts of the duodenum and jejunum. In chickens older than 12 weeks, gradual reduction of worm burden is more successful than the younger birds. Female chickens exert a short-lived but higher level of protection by passing IgY to chicks in the form of egg yolk antibodies. In laying conditions, immunity differs between breeds. This review provides an overview of the silent but inevitable pathological changes induced by A. galli and the interaction of host immunity with the parasite.

Morphological and phylogenetic analysis of Raillietina spp. in indigenous chickens (Gallus gallus domesticus) in Bangladesh.

Raillietina spp. (Cestoda: Davaineidae), the most common cestodes in indigenous chickens, cause a substantial production loss in poultry industry in Bangladesh. Here, we estimated the prevalence, confirmed the species and determined the genetic pattern of species of Raillietina using molecular tools. We collected and examined 375 chickens randomly from household of different villages of Mymensingh sadar and Gouripur upazila, Mymensingh district and adult parasites were isolated and identified. Genomic DNA was extracted from collected parasites, amplified ITS-2 and ND-1 genes, sequenced and analyzed. Out of 375 samples, 270 (72.0%) were found positive with Raillietina species and mean worm burden was 10.46 ± 0.56. Microscopically, three species of Raillietina, such as R. cesticillus (37.9%), R. echinobothrida (41.1%) and R. tetragona (52.8%) were detected on the basis of their morphological features. The total length, length and width of scolex, sucker and rostellum were also measured. Among different factors, age, farming nature and flock size of chickens were significantly (p < 0.05) influenced Raillietina infections. For further validation, the sequences of ITS-2 gene generated in this study were matched with reference sequences of R. cesticillus, R. echinobothrida and R. tetragona and found 99.63% - 100% similarity. The phylogenetic analyses of ITS-2 and ND-1 sequences were clustered together with the reference sequences of R. cesticillus, R. echinobothrida and R. tetragona confirming microscopic identification. This is the first confirmation of species of Raillietina along with the prevalence of the species, which will be helpful for the formulation of a control strategy and provide basic information for further molecular study.

Diversity and prevalence of gastrointestinal parasites of Black Bengal goats in Natore, Bangladesh.

Objectives: The objective of this work was to estimate the diversity of gastrointestinal (GI) parasite species, their prevalence, and risk factors in Black Bengal goats (BBGs) of Natore, Bangladesh. Materials and Methods: Fecal samples from randomly selected 260 BBGs were processed through Stoll's ova counting method, floatation, and simple sedimentation method. Microscopy-based identification of parasitic eggs, cysts, or oocysts was made. A semi-structured questionnaire-based data on host and management practices were collected from the owner. Data analysis was done using Statistical Package for Social Sciences. Results: The overall prevalence of GI parasites in BBGs was 65.4%, with an individual prevalence of 8.5% for Fasciola gigantica, 21.5% for Paramphistomum spp., 20% for Haemonchus spp., 34.2% for Strongyloides spp., 8.5% for Trichuris spp., and 9.2% for Eimeria spp. No significant effect of host age, gender, body condition, animal rearing system, or housing floor type was observed on parasitism. Animals of young age, female, poorly body-conditioned, living in a free-range system, and housed on a muddy floor had a relatively higher susceptibility to infection. Deworming had a significant impact on reducing the frequency of caprine GI parasitism. Conclusions: Despite the significant effect of anthelmintic, the elevated prevalence of GI parasites in BBGs suggests a critical need for developing effective strategies to prevent caprine parasitoses.

Ex-vivo efficacy of commercially available anthelmintics against blood feeding stomach worm Haemonchus contortus of ruminants.

Haemonchus contortus is the most prevalent and pathogenic gastrointestinal nematodes (GINs) in ruminants causing extensive economic losses. It is essential to estimate the efficacy of common commercially available anthelmintics against Haemonchus contortus parasite. Here, we standardized an ex-vivo culture platform for H. contortus and evaluated the efficacy of commonly used anthelmintics namely, albendazole (ABZ), levamisole (LVM), ivermectin (IVM), closantel (CLS) and rafoxanide (RFX). Adult worms were collected from abomasa of slaughtered animals, cultured in MEM, DMEM, M199 or RPMI with or without 20% FBS for up to 72 h. Cultured worms were incubated with ABZ, LVM, IVM, RFX or CLS in DMEM supplemented with 20% FBS at different concentrations (0.5-50 µg/ml) in triplicates and examined at 0, 3, 6, 12, 24, 36 and 48 h post treatment. Of the culture conditions, DMEM supplemented with 20% FBS supported the survival of H. contortus for (P < 0.001) longer period of time which was used in the evaluation of anthelmintics. The efficacy of CLS and RFX were significantly (P < 0.001) higher than other drugs and 100% mortality was observed at 2 µg/ml of CLS and RFX within 12 h post treatment. However, ABZ, LVM, and IVM showed significant effect at the concentration of 50 µg/ml with 48, 36, and 24 h, respectively. Morphological changes included severe cuticle disruption around the buccal cavity, posterior region and vulva as well as loss of cuticle structure integrity coupled with expulsion and fragmentation of digestive components of parasites when treated with 50 µg/ml of ABZ, LVM, and IVM and 2 µg/ml of RFX and CLS. Collectively, DMEM supplemented with 20% FBS can be used as ex-vivo culture platform for maintenance of H. contortus, and RFX and CLS can be used as the promising drugs for the prevention, control and treatment of H. contortus infections.

Molecular detection of Babesia and Theileria from crossbred cattle in Sirajganj and Rangpur districts of Bangladesh.

BACKGROUND: Babesia and Theileria are potential threats to the livestock industry, causing considerable economic losses. These tick-borne blood parasites are more prevalent in crossbred cattle than local cattle in Bangladesh. OBJECTIVES: To confirm the species of Babesia and Theileria in crossbred cattle from the northern part of Bangladesh using conventional and molecular tools. METHODS: A total of 385 crossbred cattle blood samples were subjected to DNA extraction and PCR. For molecular detection, B. bigemina rhoptry-associated protein 1a, B. bovis spherical body protein-4, and Theileria spp. 18S rRNA were used as the marker genes. RESULTS: Using PCR, only 72 (18.7%) samples were found piroplasm positive, of which 12.2% Theileria, 4.7% Babesia, and 1.8% mixed infections. Both Babesia (7.3%), Theileria (7.7%) and mixed (2.8%) infections were detected in Sirajganj, and only Theileria (20.4%) was detected in Rangpur district. By PCR and nPCR we detected B. bigemina and T. annulata in Sirajganj district, and Theileria sp. in Rangpur district. The target gene sequences of isolated pathogens confirmed B. bigemina and T. annulata, and Theileria sp from these samples. Blood smears of all samples were also examined microscopically for Babesia and/or Theileria spp. and 14.3% of samples were found positive, of which 5.9% Babesia and 8.3% Theileria. Generally, the pathogens detected in Sirajgang and Rangpur were genetically related to South Asia, particularly South East Asian isolates. CONCLUSIONS: These findings provide information for a better understanding of the epidemiology of Babesia and Theileria as well as to improve the approaches for diagnosis and control of tick-borne diseases in Bangladesh.

Mammalian and Avian Larval Schistosomatids in Bangladesh: Molecular Characterization, Epidemiology, Molluscan Vectors, and Occurrence of Human Cercarial Dermatitis.

Schistosomiasis is a neglected tropical disease (NTD) caused by blood flukes (Schistosoma spp.). Schistosomatids affect a wide array of vertebrate hosts, including humans. In the present study, multiple species of schistosomatids were identified by isolating schistosomatid cercariae (SC) from naturally infected snails. We also described different biotic and abiotic factors influencing SC infections in snails and reported human cercarial dermatitis (HCD) for the first time in Bangladesh. A total of 22,012 snails of seven species: Lymnaea auricularia, L. luteola, Indoplanorbis exustus, Physa acuta, Viviparus bengalensis, Brotia spp., and Thiara spp., were collected and examined. Among these snails, 581 (2.6%) belonging to five species: L. luteola, L. auricularia, P. acuta, I. exustus, and V. bengalensis, were infected with SC. The rate of infection was the highest for L. luteola (11.1%), followed by L. auricularia (5.3%), and was the lowest for V. bengalensis (0.4%). Prevalence in snails was the highest in September (16.8%), followed by October (9.5%) and November (8.8%), and was the lowest in colder months, such as January (1.8%) and February (2.1%). Infections with schistosomatids were more common in larger snails and snails collected from sunny areas. We confirmed the presence of Schistosoma indicum, S. incognitum, S. nasale, S. spindale, and Trichobilharzia szidati by PCR and sequencing. Through a questionnaire survey, we detected HCD in 214 (53.5%) individuals, and the infection rate was almost equally distributed across all professions. Collectively, the present results suggest that lymnaeid snails are the main vector for Schistosoma spp. prevalent in Bangladesh, and schistosomatids with zoonotic potential are also prevalent.

Morphometry and genetic diversity pattern of Cysticercus tenuicollis, an important food-borne taeniid metacestode in goats in Bangladesh.

Cysticercus tenuicollis is a larval stage of Taenia hydatigena resulting in cysticercosis, and responsible for enormous economic loses, especially in livestock production. Here, we planned to determine the prevalence and explore genetic variation of C. tenuicollis isolated from goats based on small subunit ribosomal RNA (rrnS) and cytochrome oxidase subunit 1 (cox1). To do this, samples were collected from different slaughter houses of municipal areas such as Bramhapalli slaughterhouse, Jubileeghat slaughterhouse and Mesuabazar slaughterhouse at Mymensingh sadar, and tentatively identified by morphological and morphometrical analysis. To study genetic variation, DNA was extracted from C. tenuicollis, and amplified rrnS and cox1 genes using specific primers, and were sequenced. Among 1372 examined animals, 177 (12.9%) were infected with C. tenuicollis. Cysts were recovered from peritoneum (7.9%), liver (4.4%) and urinary bladder (0.6%) of the infected animals. Females (18.9%) and adults (20.7%) were significantly more susceptible than male (8.8%) and young (9.3%), respectively. Genetic analysis defined 8 distinct rrnS genotypes and 9 unique cox1 haplotypes among 20 C. tenuicollis isolates. The nucleotide diversities were 0.00283 and 0.00434 for rrnS and cox1 genes, respectively. Neighbor joining (NJ) trees of rrnS and cox1 gene were constructed and the studied sequences were clustered with reference sequences of T. hydatigena with strong nodal support (100%). To compare Bangladeshi isolates, a median joining network was constructed with the population from other geographical regions and hosts. This led to a clustering pattern, but the clusters were not built with unique geographical regions or hosts. In conclusion, this is the first study that describes the genetic variation of T. hydatigena population and suggests the existence of host-specific variants. Therefore, it is fundamental to dispose infected viscera, restrict dog movement and proper management of slaughter house for the prevention and control of cysticercosis.

Phylogenetic analysis of Eimeria tenella isolated from the litter of different chicken farms in Mymensingh, Bangladesh.

BACKGROUND: Eimeria tenella is the most pathogenic intracellular protozoan parasite of seven Eimeria species causing chicken coccidiosis around the world. This species is particularly responsible for caecal coccidiosis leading to serious morbidity-mortality and financial loss in poultry production. METHODS: The present study explored the genetic diversity of E. tenella. Litter slurry was collected from 18 broiler farms located in Mymensingh district, Bangladesh. Litter samples were processed for oocyst isolation-identification using parasitological techniques followed by genomic DNA extraction from sporulated oocysts. For molecular analysis, the internal transcribed spacer 1 gene of E. tenella was amplified using species-specific primers and sequenced. After editing and alignment, 263 bp sequences were used for analysis. RESULTS: Genetic analysis showed seven distinct genotypes and detected six single nucleotide polymorphisms among the 18 E. tenella isolates. The nucleotide and genotype diversity were 0.00507 and 0.8235, respectively. A phylogenetic tree was constructed with 66 sequences (seven studied genotypes and 59 reference sequences from GenBank database). The neighbour-joining tree represented that the studied E. tenella isolates were grouped with reference E. tenella isolates with strong nodal support (100%) and the nucleotide sequences of E. tenella, E. necatrix, E. acervulina, E. brunetti, E. maxima, E. mitis and E. praecox formed separate clusters without any geographical boundaries. CONCLUSIONS: This is the first study on the genetic analysis of E. tenella from Mymensingh district, Bangladesh. These findings will provide baseline data on the species conformation and genetic variations of E. tenella. Further extensive investigation will be needed to reveal the population genetic structure of this parasite and thus will facilitate the planning of effective control strategies.

A large-scale epidemiological investigation on trematode infections in small ruminants in Bangladesh.

BACKGROUND: The important trematode species in small ruminants: Paramphistomum sp., Fasciola spp. and Schistosoma spp. seriously affect the productivity of domestic ruminants in endemic areas. METHODS: In the present study, we identified the potential risk factors associated with trematodes infections in small ruminants in seven topographic zones of Bangladesh using simple sedimentation and modified Stoll' ova counting technique. RESULTS: A total of 2440 samples were examined, where 965 were found positive with one or more trematode species with an overall prevalence of 39.5% (95% CI, 37.6%-41.5%) and intensity of infection was 264.77 ± 9.86 egg per gram of faeces. Three trematode species were identified namely Paramphistomum sp. (34.1%, 32.2%-36.0%), Fasciola spp. (7.5%, 6.5%-8.6%) and Schistosoma spp. (2.7%, 2.1%-3.5%). Prevalence of co-infection was 4.8%. The spatial distribution of trematode infections varied from 29.5% to 53.6%. Univariate analysis revealed that physiological condition of females, body condition, farming system, deworming and season were significantly (p < 0.05) associated with trematodes infections in small ruminants. By multiple logistic regression model, three factors such as physiological condition of females (pregnant and lactating), poor body condition and animals without deworming were identified as potential risk factors for trematodes infection in small ruminants. CONCLUSION: Trematode infections are prevalent in the study areas and Paramphistomum sp. is most common in different areas among the identified trematodes species. Government should take necessary action to appraise an effective control strategy of trematode infections in small ruminants.

Frequency of benzimidazole resistance in Haemonchus contortus populations isolated from sheep and goats in Bangladesh.

Anthelmintic resistance against gastrointestinal nematodes especially H. contortus of sheep and goat is a global issue. To address the gravity and extension of AR in Bangladesh, genotyping of 160 adult H. contortus parasitesw ere performed to confirm benzimidazole resistance allele from different geographic zones of Bangladesh based on allele specific PCR (AS-PCR). The genotype frequencies were 9.4% for homozygous resistant (rr), 61.2% for heterozygous (rS) and 29.4% for homozygous susceptible (SS) among the selected areas. The allelic frequency of the mutation conferring resistance (r) ranged from 27.5% to 52.5% indicating substantial existence of benzimidazole resistance in H. contortus in small ruminant nematodes. Therefore, it can be concluded that genotyping the F200Y polymorphism can be used to monitor the resistance and thereby to enhance the control on the development of anthelmintic resistance against H. contortus in small ruminant nematodes.

ITS1-PCR based identification of chicken Eimeria species in poultry litter from Mymensingh district, Bangladesh.

OBJECTIVES: The purpose of this study was to determine the species composition of Eimeria circulating in Mymensingh district, Bangladesh, using Internal Transcribed Spacer 1 (ITS1) sequences in polymerase chain reaction (PCR) assay. MATERIALS AND METHODS: Coccidian oocysts were isolated and sporulated in a solution containing 2% potassium dichromate from litter slurry collected from 13 commercially active broiler farms in the research region. Genomic DNA was isolated from sporulated oocysts and used to amplify the Eimeria species-specific ITS1 gene by PCR amplification. Electrophoresis of 1.5% agarose gel was used to visualize the amplified PCR products. RESULTS: In the study samples from Mymensingh district, Bangladesh, the presence of Eimeria brunetti, Eimeria acervulina, Eimeria necatrix, Eimeria mitis, and Eimeria tenella was identified. CONCLUSIONS: The findings of this study may shed light on the zonal approach to chicken coccidiosis control. Additionally, it suggests that ITS1-based PCR might be used in the field to accurately identify Eimeria species.

Knowledge, attitude and practices (KAP) towards Anthrax among livestock farmers in selected rural areas of Bangladesh.

BACKGROUND: Bacillus anthracis is a zoonotic bacterium that affects wide numbers of vertebrate animals and man and has life threating potential both in animal s as well as humans. METHODS: A cross sectional study was conducted to assess the knowledge about, attitudes towards, and practices addressing (KAPs) anthrax among community members in selected upazillas' of Meherpur and Sirajgonj districts for the prevention and control of anthrax using a structured questionnaire. RESULTS: A total of 424 community members were considered in this study irrespective of their age and sex. Most of the respondents were female (57.54%) and about half were illiterate (47.40%). Most of the respondents (86.32%) were self-employed with crop and livestock farming. Among the self-employed farmers, cattle (63.73%) were the highest reared animals. Among the respondents, 37.26% had no knowledge about anthrax. On the other hand, among the existing knowledge level, 46.69% received information of anthrax from neighbour, 74.05% and 56.82% were concerned about the mode of transmission of anthrax from animal to human through eating, handling and soil. Respondents usually collected vaccine from quack (58.25%) and vaccination status was highest in Kamarkhand (52.03%) and lowest in Gangni upazilla (10.82%). Overall 62.74% community members considered that anthrax is a fatal disease for livestock and 82.54% people disposed carcass in buried method. CONCLUSION: The study findings indicated that the community members had average knowledge on cause, symptoms, transmission and prevention of anthrax. The supplied vaccine was found negligible with the number of livestock in the studied upazilas. Veterinary and Medical health planners should design and implement interventions for awareness building on anthrax under One Health (OH) approach for educating the community people on anthrax control and prevention.

Prevalence and factors influencing gastrointestinal parasitic infections in sheep in Bangladesh.

Gastrointestinal (GI) parasites are major contributors to decrease productivity in livestock over the world. A cross-sectional study was conducted in different areas of Bangladesh to determine the prevalence of GI parasitic infections and their association with the biotic and abiotic factors in sheep. A total of 572 faecal samples were collected from the selected areas of Bangladesh and microscopic examination was performed for the identification of parasites using flotation and sedimentation technique. Out of 572, 441 animals were found infected with one or more species of GI parasites with an overall prevalence of 77.1%. Nine types of parasites from four different classes were detected namely Strongyles (42.1%), Strongyloides sp. (27.1%) and Trichuris sp. (1.0%), Moniezia sp. (2.4%), Paramphistomum cervi (32.5%), Fasciola gigantica (6.1%) and Schistosoma sp. (3.5%), coccidia (16.6%) and Balantidium coli (7.9%). Nematodes infections (56.8%) were significantly highest among trematodes (37.9%), protozoa (24.4%) and cestode (2.4%). In the present study, all the biotic factors including sex, age, physiological condition of female and body condition score (BCS) of animals were insignificantly (p>0.05) associated with the prevalence of GI parasitic infection in sheep but among the abiotic factors, muddy housing of animals, rainy season, having no knowledge about GI parasites and illiteracy of farmers were significantly (p<0.05) associated with the GI parasitic infections. This epidemiological investigation will assist to build a suitable control program against GI parasites in sheep and thus, help to prevent production loss and increase livelihood of small holder farmers.

Gastro-intestinal nematodes in goats in Bangladesh: A large-scale epidemiological study on the prevalence and risk factors.

Goats greatly influence the economic sustainability of rural communities. However, parasitic diseases, especially gastrointestinal nematodes (GINs) are a major constraint on profitable small ruminants' production worldwide. During July- 2015 to June- 2016, we conducted a cross sectional study within seven topographic zones of Bangladesh to explore the level of infection and associated risk factors of GINs infections of goats. The study followed standard flotation and modified McMaster techniques. Among 1998 samples from goats; 1241 (62.1%) were found to be infected with one or more species of GINs by fecal examination for nematode eggs. The identified nematodes were strongyles (51.9%), Strongyloides sp. (19.0%) and Trichuris spp. (2.9%). By coproculture, we identified Haemonchus spp., Oesophagostomum spp., Trichostrongylus spp. and Bunostomum spp. in the different topographic zones. According to univariate analysis; young age, other breed than Black Bengal, animals in poor condition, backyard rearing system, muddy housing, illiterate farmers and rainy season were found significantly associated with GINs infections. Besides, other breed than Black Bengal, animals in poor condition, backyard rearing system, muddy housing and illiterate farmers were identified as the risk factors of GINs infections in goats. This is the first detailed epidemiological investigation of GINs of goats in Bangladesh. The epidemiological findings are expected to help formulate effective control strategies against GINs infections in goats by improving health status of animals, management system and education level of the farmers.

Multiple anthelmintic resistance in gastrointestinal nematodes of small ruminants in Bangladesh.

Anthelmintic resistance (AR) against gastrointestinal nematodes (GINs) of sheep and goats is a global concern. To address the problem, this study assessed the status of AR in different government and private sheep and goat farms in Bangladesh. We conducted fecal egg count reduction test (FECRT) and Egg hatch assay (EHA) experiments. For the detection of resistant larvae, pooled fecal samples from treated and non-treated groups were subjected to coproculture. Furthermore, 195 adult Haemonchus parasites were genotyped to ascertain benzimidazole (BZ) resistance allele from seven topographic zones of Bangladesh using allele specific PCR (AS-PCR). In FECRT, the percentage reduction along with 95% confidence intervals indicated that GINs were resistant to albendazole (ABZ), levamisole (LEV) and ivermectin (IVM). Coproculture revealed that Haemonchus spp., Oesophagostomum spp. and Trichostrongylus spp. were resistant to anthelmintics. ABZ resistance was also confirmed by in vitro EHA in all the farms except the private goat farm in Mymensingh. The genotype frequencies were 6% for homozygous resistant (rr), 59% for heterozygous (rS) and 35% for homozygous susceptible (SS) among different topographic zones. The allelic frequency of the mutation conferring resistance (r) ranged from 25% to 47% signifying resistance to BZ in nematodes of sheep/goats. The genotype frequencies (rr, rS and SS) and allelic frequencies (r and S) varied significantly (p˂0.05) in different zones in Bangladesh. Overall, the data suggest an alarming condition created by multiple AR in Bangladesh.

Molecular detection of Toxoplasma gondii from aborted fetuses of sheep, goats and cattle in Bangladesh.

The study was planned to apply the PCR method for detection of T. gondii infection in sheep, goats and cattle aborted fetuses from Mymensingh, Bangladesh. A total of 58 fetal tissue samples (brain, liver, heart, skeletal muscle and placenta) of sheep (5), goats (5) and cattle (2) were selected for study. Aborted fetuses were taken from serologically positive mothers by indirect ELISA. Among them 24 and 34 samples were subjected for PCR assay by using TgB1 and TgTox4 primers respectively. DNA fragments were visualized under UV illumination after gel run. The results demonstrated 15.52% tissue samples from sheep and goat aborted fetuses were positive for T. gondii parasite. Among different tissue samples, brain, liver and heart showed presence of T. gondii parasite. None of tissue samples showed positive in case of cattle. The results of the PCR exhibited that T. gondii infection might be considered as one of the major causative agents for abortion in ewes and does. Further studies are needed to improve our knowledge on different genotypes of T. gondii that infect sheep, goat and cattle population in Bangladesh.

Genetic diversity patterns of Haemonchus contortus isolated from sheep and goats in Bangladesh.

Haemonchus contortus is the most prevalent parasitic nematode among the Trichostrongylids causing severe health hazards leading to production losses in small ruminants around the world. This study was conducted to explore genetic variation within and among H. contortus populations from seven topographic zones of Bangladesh in small ruminants using second internal transcribed spacer (ITS-2) of nuclear ribosomal DNA and the mitochondrial nicotinamide dehydrogenase subunit 4 (nad4) genes. To do this, a total of 95 adult H. contortus were collected from abomasa of slaughtered sheep and goats from seven different geographic zones of Bangladesh. After the extraction of DNA, ITS-2 of nuclear ribosomal DNA and partial region of the mitochondrial nad4 genes were amplified and sequenced for 95 and 85 worms, respectively. After editing and alignment, sequences were employed for analysis to determine sequence variation, genetic diversity and population genetic structure. Genetic analysis defined 19 distinct ITS-2 genotypes and 77 unique nad4 haplotypes among the H. contortus isolates. The nucleotide diversities were 0.0098 and 0.025 for ITS-2 and nad4 gene, respectively. Phylogenetic analysis (neighbor joining, maximum likelihood and maximum parsimony) of haplotypes indicated the existence of two populations without marked specification of host and locations within H. contortus populations in Bangladesh. By population genetic analysis, 93.67% of genetic variance was partitioned within the population. Very low genetic differentiation but high gene flow was observed among different populations of H. contortus in Bangladesh. This is the first study on genetic variability of H. contortus isolates of small ruminants in Bangladesh. Our study could be the basis for further molecular epidemiological studies, using more discriminative markers and tracing possible changes in the population structure of H. contortus.