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Infection, Genetics and Evolution :... Dec 2021Tabanids (syn. horse flies) are biting-flies of medical and veterinary significance because of their ability to transmit a range of pathogens including trypanosomes -...
Tabanids (syn. horse flies) are biting-flies of medical and veterinary significance because of their ability to transmit a range of pathogens including trypanosomes - some species of which carry a combined health and biosecurity risk. Invertebrate vectors responsible for transmitting species of Trypanosoma between Australian wildlife remains unknown, thus establishing the role of potential vector candidates such as tabanids is of utmost importance. The current study aimed to investigate the presence of indigenous trypanosomes in tabanids from an endemic area of south-west Australia. A total of 148 tabanids were collected, with morphological analysis revealing two subgenera: Scaptia (Pseudoscione) and S. (Scaptia) among collected flies. A parasitological survey using an HRM-qPCR and sequencing approach revealed a high (105/148; 71%) prevalence of trypanosomatid DNA within collected tabanids. Individual tissues - proboscis (labrum, labium and mandibles, hypopharynx), salivary glands, proventriculus, midgut, and hindgut and rectum - were also tested from a subset of 20 tabanids (n = 140 tissues), confirming the presence of Trypanosoma noyesi in 31% of screened tissues, accompanied by T. copemani (3%) and T. vegrandis/T.gilletti (5%). An unconfirmed trypanosomatid sp. was also detected (9%) within tissues. The difference between tissues infected with T. noyesi compared with tissues infected with other trypanosome species was statistically significant (p < 0.05), revealing T. noyesi as the more frequent species detected in the tabanids examined. Fluorescence in situ hybridisation (FISH) and scanning electron microscopy (SEM) confirmed intact parasites within salivary glands and the proboscis respectively, suggesting that both biological and mechanical modes of transmission could occur. This study reveals the presence of Australian Trypanosoma across tabanid tissues and confirms intact parasites within tabanid salivary glands and the proboscis for the first time. Further investigations are required to determine whether tabanids have the vectorial competence to transmit Australian trypanosomes between wildlife.
Topics: Animals; Animals, Wild; Biosecurity; Diptera; Insect Vectors; Trypanosoma; Trypanosomiasis; Western Australia
PubMed: 34823027
DOI: 10.1016/j.meegid.2021.105152 -
Frontiers in Physiology 2020The gastrointestinal tract in metazoans consists of diverse epithelial cells with distinct cell morphology and physiological functions. The development and homeostasis...
The gastrointestinal tract in metazoans consists of diverse epithelial cells with distinct cell morphology and physiological functions. The development and homeostasis of gastrointestinal epithelia involve spatiotemporal regulation by many signaling pathways, essential to confer their region-specific function and identity. The adult midgut and the mammalian intestine share a high degree of conservation between such signaling pathways. Due to availability of sophisticated techniques for genetic manipulation, is an excellent model to study mechanisms of tissue homeostasis regulation in a regionally defined manner. The gastric region located in the middle-midgut coincides with the region containing fewest number of stem cells. It is also known as the copper cell (CC) region since it is composed of specialized groups of acid-secreting CCs, along with interstitial cells and enteroendocrine cells. The generation and maintenance of these cell populations are determined by the bone morphogenic protein-like Decapentaplegic (Dpp) signaling pathway. The morphogenic gradient of the Dpp signaling activity induces differential expression of specific transcription factors () and (, which are required for the generation of various cell types specific to this region. In this study, we investigated the role of Dve in regulation of tissue homeostasis in the CC region. Our studies reveal that ectopic expression of in stem cells suppresses their self-renewal throughout the intestine. We further demonstrate that Dve is not required for generation of CCs. Higher levels of Dve can alter cell specification by inhibition of expression, which in turn prevents CC formation during homeostasis.
PubMed: 32760283
DOI: 10.3389/fphys.2020.00711 -
Royal Society Open Science Jan 2020The gastrointestinal tract (GIT) consists of connected structures that vary in function and physiology, and different GIT sections potentially provide different habitats...
The gastrointestinal tract (GIT) consists of connected structures that vary in function and physiology, and different GIT sections potentially provide different habitats for microorganisms. Birds possess unique GIT structures, including the oesophagus, proventriculus, gizzard, small intestine, caeca and large intestine. To understand birds as hosts of microbial ecosystems, we characterized the microbial communities in six sections of the GIT of two shorebird species, the Dunlin and Semipalmated Sandpiper, identified potential host species effects on the GIT microbiome and used microbial source tracking to determine microbial origin throughout the GIT. The upper three GIT sections had higher alpha diversity and genus richness compared to the lower sections, and microbial communities in the upper GIT showed no clustering. The proventriculus and gizzard microbiomes primarily originated from upstream sections, while the majority of the large intestine microbiome originated from the caeca. The heterogeneity of the GIT sections shown in our study urges caution in equating data from faeces or a single GIT component to the entire GIT microbiome but confirms that ecologically similar species may share many attributes in GIT microbiomes.
PubMed: 32218980
DOI: 10.1098/rsos.191609 -
Applied and Environmental Microbiology Apr 2023Yersinia pestis (the agent of flea-borne plague) must obstruct the flea's proventriculus to maintain transmission to a mammalian host. To this end, Y. pestis must...
Yersinia pestis (the agent of flea-borne plague) must obstruct the flea's proventriculus to maintain transmission to a mammalian host. To this end, Y. pestis must consolidate a mass that entrapped Y. pestis within the proventriculus very early after its ingestion. We developed a semiautomated fluorescent image analysis method and used it to monitor and compare colonization of the flea proventriculus by a fully competent flea-blocking Y. pestis strain, a partially competent strain, and a noncompetent strain. Our data suggested that flea blockage results primarily from the replication of Y. pestis trapped in the anterior half of the proventriculus. However, consolidation of the bacteria-entrapping mass and colonization of the entire proventricular lumen increased the likelihood of flea blockage. The data also showed that consolidation of the bacterial mass is not a prerequisite for colonization of the proventriculus but allowed Y. pestis to maintain itself in a large flea population for an extended period of time. Taken as the whole, the data suggest that a strategy targeting bacterial mass consolidation could significantly reduce the likelihood of Y. pestis being transmitted by fleas (due to gut blockage), but also the possibility of using fleas as a long-term reservoir. Yersinia pestis (the causative agent of plague) is one of the deadliest bacterial pathogens. It circulates primarily among rodent populations and their fleas. Better knowledge of the mechanisms leading to the flea-borne transmission of Y. pestis is likely to generate strategies for controlling or even eradicating this bacillus. It is known that Y. pestis obstructs the flea's foregut so that the insect starves, frantically bites its mammalian host, and regurgitates Y. pestis at the bite site. Here, we developed a semiautomated fluorescent image analysis method and used it to document and compare foregut colonization and disease progression in fleas infected with a fully competent flea-blocking Y. pestis strain, a partially competent strain, and a noncompetent strain. Overall, our data provided new insights into Y. pestis' obstruction of the proventriculus for transmission but also the ecology of plague.
Topics: Animals; Siphonaptera; Yersinia pestis; Plague; Proventriculus; Microscopy; Insect Vectors; Mammals
PubMed: 36939324
DOI: 10.1128/aem.02091-22 -
Animal : An International Journal of... Aug 2022Heat stress (HS) dramatically impairs the growth performance of broiler chickens, mainly as a consequence of reduced feed intake due to the loss of appetite. This study...
Heat stress (HS) dramatically impairs the growth performance of broiler chickens, mainly as a consequence of reduced feed intake due to the loss of appetite. This study was aimed at evaluating the alterations induced by chronic HS conditions on the morphological and morphometric features of the gastrointestinal (GI) tract and on the expression of some enteroendocrine cells (EECs) involved in the regulation of feed intake in chickens. Three hundred male chickens (Ross 308) were divided into two experimental groups and raised either in thermoneutral environment for the whole fattening period (0-41 days) (TNT group) or subjected to chronic HS conditions (30 °C for 24 h/day) from 35 to 41 days (HS group). Samples of proventriculus, duodenum, jejunum and cecum were collected from 24 broilers (12/group). Haematoxylin-eosin was used for the morphometric evaluations, while immunohistochemistry was applied for the evaluation of EECs expressing ghrelin (GHR), cholecystokinin (CCK), neuropeptide Y (NPY), glucagon-like peptide-1 (GLP-1), and serotonin (5-HT). In the proventriculus, HS reduced total wall thickness and mucous layer height (P ≤ 0.01) as well as mean diameter, circumference, and area of the compound tubular glands (P ≤ 0.001) with respect to TNT. The small intestine of HS birds was characterised by decreased villous height and total thickness (duodenum, P ≤ 0.01; jejunum, P ≤ 0.001), whereas crypt depth and width were reduced only in the jejunum (P ≤ 0.01). HS had negligible effects on the morphological aspects of the cecum. In the proventriculus, an increase in GHR and NPY EECs was observed in response to HS (P ≤ 0.001). Similarly, the small intestine villi of the HS group showed greater GLP-1 (P ≤ 0.05), 5-HT (P ≤ 0.001) and CCK (P ≤ 0.01) EECs. Moreover, the expression of 5-HT EECs was higher in the duodenal (P ≤ 0.01) and jejunal (P ≤ 0.01) crypts of HS birds, whereas GLP-1 and CCK EECs increased only in jejunal crypts (P ≤ 0.05). Finally, 5-HT EEC expression was increased in the cecum of HS group (P ≤ 0.01). In conclusion, these outcomes demonstrate that chronic HS induces morphometric alterations not only in the small intestine but also in a key organ such as the proventriculus. Furthermore, HS conditions affect the presence and distribution of EECs, suggesting that some GI peptides and biogenic amine may be implicated in the regulation of appetite and voluntary feed intake in heat-stressed broiler chickens.
Topics: Animal Feed; Animals; Chickens; Cholecystokinin; Eating; Glucagon-Like Peptide 1; Heat Stress Disorders; Heat-Shock Response; Hot Temperature; Male; Serotonin
PubMed: 35907384
DOI: 10.1016/j.animal.2022.100600 -
Open Veterinary Journal Apr 2023Newcastle disease is very pathogenic in chickens, whereas in ducks, the disease does not show any clinical symptoms.
BACKGROUND
Newcastle disease is very pathogenic in chickens, whereas in ducks, the disease does not show any clinical symptoms.
AIMS
To compare the clinical symptoms features, pathological lesions, viral distribution, and apoptosis response caused by the Newcastle disease virus (NDV) in domestic chicken and Alabio duck.
METHODS
Forty domestic chickens and 40 Alabio ducks were separated into four groups: domestic chicken and Alabio duck treatment groups, where each was infected by NDV velogenic ducks/Aceh Besar_IND/2013/eoAC080721 in 10ELD dosage. The domestic chicken and Alabio duck control groups were each inoculated with Phosphate Buffer Saline. The infection route was intraorbital, 0.1 ml in volume. Symptoms were observed from day 1 until day 7 post-infection (PI). Necropsy was performed on days 1, 2, 3, 5, and 7 PI for organ collection.
RESULTS
Symptoms observed were disorders in the respiratory, gastrointestinal, and nervous systems, followed by 100% mortality in domestic chickens. In Alabio ducks, there were only depression and slight lethargy. The lesion in domestic chicken day 1 appeared by the lungs, thymus, Fabricius bursa, spleen, and kidney. On day 3 PI, lesions were also found in the heart, proventriculus, duodenum, and cecal tonsil. On days 5 and 7 PI, the trachea and brain lesions were found. In Alabio ducks, lesions were found in the lungs, thymus, spleen, and proventriculus on day 1. Afterward, on day 3, light lesions were found in the heart. On day 5, lesions were found in the trachea and brain; finally, on day 7, light lesions were only found in the thymus, spleen, and brain. Immunopositive reaction NDV in domestic chicken was highest in the proventriculus, duodenum, cecal tonsil, and lymphoreticular organs. In the Alabio duck, it was highest in the duodenum and cecal tonsil. The caspase-3 percentage in domestic chicken increased on day 3 PI; in Alabio ducks, on day 2 PI.
CONCLUSION
Clinical symptoms and pathological lesions were faster and more severe in domestic chickens. The immunopositive reaction NDV in domestic chicken continued to increase, while in Alabio ducks, it decreased until the last observation day. Apoptosis percentage increased earlier in the Alabio duck than in domestic chicken.
Topics: Animals; Newcastle Disease; Ducks; Chickens; Immunohistochemistry; Borneo; Newcastle disease virus
PubMed: 37251268
DOI: 10.5455/OVJ.2023.v13.i4.5 -
Polish Journal of Veterinary Sciences Mar 2024Avian gastric yeast (Macrorhabdus ornithogaster) is a microorganism that infects aviary birds worldwide, both captive and wild. A total number of 352 birds, belonging to...
Avian gastric yeast (Macrorhabdus ornithogaster) is a microorganism that infects aviary birds worldwide, both captive and wild. A total number of 352 birds, belonging to 18 avian species, were examined from 2019 to 2022 for M. ornithogaster, using fecal smears of live birds or cytological samples of the proventriculus taken at necropsy. These cytological samples were taken from birds that died from different causes. Some of the birds exhibited symptoms such as lethargy, regurgitation, weight loss and anorexia. Faecal samples were collected from all the birds and analysed for gastric yeast using a direct smear and Gram-staining method. The microorganism was diagnosed most frequently in budgerigars (55.5%), the African gray parrot (33.3%), and nymphs (34.3%). The prevalence of M. ornithogaster in canaries was 10%. The infection was detected in 31% of the examined birds, which shows that the occurrence of M. ornithogaster in exotic birds is common. No clinical signs were observed in the vast majority of birds that tested positive for gastric yeast.
Topics: Animals; Saccharomyces cerevisiae; Bird Diseases; Saccharomycetales; Melopsittacus
PubMed: 38511651
DOI: 10.24425/pjvs.2024.149335 -
Poultry Science Jun 2021In a 3 × 2 factorial arrangement, effects of feed form (crumbles (CWS), mash (MWS), both with inclusion of 3% finely ground wheat straw, or crumbles with inclusion...
The effects of dietary calcium and phosphorus level, and feed form during rearing on growth performance, bone traits and egg production in brown egg-type pullets from 0 to 32 weeks of age.
In a 3 × 2 factorial arrangement, effects of feed form (crumbles (CWS), mash (MWS), both with inclusion of 3% finely ground wheat straw, or crumbles with inclusion of 3% oat hulls (COH)), and dietary Ca and P (high and low Ca-P) from 0 to 16 wk of age were studied on growth performance, bone characteristics, and gizzard development of egg-type pullets. The cross-over effect of feeding strategy during rearing on laying performance and egg shell quality was studied from 19 to 32 wk of age. From 0 to 16 wk, ADG, ADFI, and feed conversion ratio (FCR) were improved with CWS and COH compared to MWS, but ADG and FCR were improved with MWS compared to CWS and COH from 11 to 16 wk. Uniformity of BW till 11 wk, and tibia breaking strength at 6 and 16 wk were higher with CWS and COH compared to MWS. Tibia ash content at 11 wk and relative empty proventriculus + gizzard weight (EPG) were lower with CWS and COH compared to MWS, also relative EPG at 11 and 16 wk was higher with COH compared to CWS. At 25 wk BW was lower with MWS compared to CWS and COH, but BW was equal for all treatments at 32 wk. The FCR for egg production was improved with COH compared to MWS. Egg shell parameters were not affected by feed form during rearing. Low Ca-P decreased BW uniformity at 6 wk, relative keel bone weight and ash content at 11 wk, tibia ash content at 11 and 16 wk, increased relative EPG at 6 wk, and improved egg shell quality at 32 wk of age. It was concluded that feeding CWS and COH compared to MWS increased growth performance, but had no clear cross-over effect on egg production. Low dietary Ca-P led to a lower bone mineralization during rearing, nevertheless improved egg shell quality at 32 wk.
Topics: Animal Feed; Animals; Calcium, Dietary; Chickens; Diet; Female; Gastrointestinal Tract; Ovum; Phosphorus
PubMed: 33940281
DOI: 10.1016/j.psj.2021.101130 -
Marine Pollution Bulletin Dec 2022The northern fulmar Fulmarus glacialis ingests a larger number of (micro)plastics than many other seabirds due to its feeding habits and gut morphology. Since 2002, they...
The northern fulmar Fulmarus glacialis ingests a larger number of (micro)plastics than many other seabirds due to its feeding habits and gut morphology. Since 2002, they are bioindicators of marine plastics in the North Sea region, and data are needed to extend the programme to other parts of their distribution areas, such as the Arctic. In this study, we provide data on ingested plastics by fulmars collected in 1997 in Kongsfjorden, Svalbard. An extraction protocol with KOH was used and for half of the birds, the gizzard and the proventricular contents were analysed separately. Ninety-one percent of the birds had ingested at least one piece of plastic with an average of 10.3 (±11.9 SD) pieces. The gizzards contained significantly more plastics than the proventriculus. Hard fragments and polyethylene were the most common characteristics. Twelve percent of the birds exceeded the EcoQO value of 0.1 g.
Topics: Animals; Plastics; Gastrointestinal Contents; Environmental Monitoring; Svalbard; Birds; Arctic Regions; Polyethylene
PubMed: 36372049
DOI: 10.1016/j.marpolbul.2022.114333 -
PLoS Pathogens Mar 2022Early diverging lineages such as trypanosomes can provide clues to the evolution of sexual reproduction in eukaryotes. In Trypanosoma brucei, the pathogen that causes...
Early diverging lineages such as trypanosomes can provide clues to the evolution of sexual reproduction in eukaryotes. In Trypanosoma brucei, the pathogen that causes Human African Trypanosomiasis, sexual reproduction occurs in the salivary glands of the insect host, but analysis of the molecular signatures that define these sexual forms is complicated because they mingle with more numerous, mitotically-dividing developmental stages. We used single-cell RNA-sequencing (scRNAseq) to profile 388 individual trypanosomes from midgut, proventriculus, and salivary glands of infected tsetse flies allowing us to identify tissue-specific cell types. Further investigation of salivary gland parasite transcriptomes revealed fine-scale changes in gene expression over a developmental progression from putative sexual forms through metacyclics expressing variant surface glycoprotein genes. The cluster of cells potentially containing sexual forms was characterized by high level transcription of the gamete fusion protein HAP2, together with an array of surface proteins and several genes of unknown function. We linked these expression patterns to distinct morphological forms using immunofluorescence assays and reporter gene expression to demonstrate that the kinetoplastid-conserved gene Tb927.10.12080 is exclusively expressed at high levels by meiotic intermediates and gametes. Further experiments are required to establish whether this protein, currently of unknown function, plays a role in gamete formation and/or fusion.
Topics: Animals; Transcriptome; Trypanosoma; Trypanosoma brucei brucei; Trypanosomiasis, African; Tsetse Flies
PubMed: 35255094
DOI: 10.1371/journal.ppat.1010346