Palliative use of self-expanding metal stents in initially anticancer treatment-intolerant patients with esophageal cancer.

BACKGROUND: The post-insertion clinical course of esophageal self-expandable metal stents (SEMS) in initially frail patients with esophageal carcinoma (EC) with dysphagia remains unclear. This study aimed to assess dysphagia improvement and evaluate prognosis in initially frail patients with advanced EC following SEMS insertion. METHODS: We retrospectively reviewed EC patients with EC who underwent esophageal SEMS insertion at our institution between January 2014 and March 2023. Inclusion criteria comprised Eastern Cooperative Oncology Group Performance Status (ECOG PS) ≥ 3 or ECOG PS 2 for individuals aged ≥ 75 years and recommendation for best supportive care by a multidisciplinary team. RESULTS: Forty-six patients met the inclusion criteria. Among them, 37 patients (80.4%) were ≥ 75 years old, and 21 patients (45.7%) exhibited ECOG PS 3 or 4. Dysphagia score (DS) ≥ 3 was observed in 27 patients (58.7%). All esophageal SEMS insertions were successfully completed. Post-procedure, there were two fatal cases of aspiration pneumonia and one perforation incident. DS improved to ≤ 1 in 25 patients (54.3%), with multivariate analysis indicating DS 3-4 and Glasgow Prognostic Score (GPS) 1-2 as negative predictive factors. The median overall survival was 4.1 months (95% confidence interval 1.8-6.5). CONCLUSIONS: Esophageal SEMS insertion effectively alleviated dysphagia in initially frail EC patients, yet prognosis remained poor, with occurrences of some fatal adverse events. Careful selection of candidates for esophageal SEMS insertions is crucial in this demographic, particularly considering the challenges in improving dysphagia for patients with DS 3-4 and GPS 1-2.

Complete response induced by nivolumab monotherapy in gastric neuroendocrine carcinoma: a case report.

No standard treatment has been established for gastric neuroendocrine carcinoma (G-NEC). We present the case of a patient with recurrent G-NEC who achieved a complete response (CR) with nivolumab. A woman in her 70 s, with no significant medical or family history of illness, underwent an upper gastrointestinal endoscopy, which revealed a Borrmann type 2 tumor in the gastric antrum. Malignant tumor cells were not detected in the endoscopic biopsy samples; however, a malignant gastric tumor was strongly suspected. Therefore, surgical resection was performed, and the tumor was pathologically diagnosed as a G-NEC with liver metastases. Adjuvant etoposide plus carboplatin was administered for four cycles, but recurrence in the liver was observed 5 months after the completion of adjuvant chemotherapy. Ramucirumab plus paclitaxel and irinotecan were introduced as second and third-line treatments. After these treatments, the mesenteric lymph node metastases expanded. Tumor mutation burden (TMB) was low (five mutations/megabase), and microsatellite instability remained stable. However, programmed death-ligand 1 Combined Positive Score (CPS) was ≥ 5 in the resected sample. Therefore, nivolumab monotherapy was introduced as a fourth-line treatment. The mesenteric lymph node metastases exhibited swelling 3 weeks after the initiation of nivolumab; however, they rapidly shrank, and CR was later achieved. Treatment with nivolumab is currently ongoing for 12 months. This is the first report of nivolumab monotherapy in a patient with G-NEC who showed pseudo-progression. Even in TMB-low and microsatellite stable cases, nivolumab may be a viable option for patients with G-NEC.

Upper gastrointestinal endoscopic submucosal dissection using an ultrathin endoscope: a retrospective, single-center evaluation.

BACKGROUND: Recent studies have reported the therapeutic use of endoscopic submucosal dissection (ESD) using an ultrathin endoscope for targeting pharyngeal and distal side lesions in the stenosis or as a less invasive treatment via the nasal route. However, the effectiveness and safety of these treatments remain undetermined. Therefore, this study aimed to review treatment outcomes and discuss the advantages and precautions of the treatments based on our experience. METHODS: This study included 13 patients with 14 lesions who underwent 14 sessions of upper gastrointestinal ESD using an ultrathin endoscope between December 2021 and August 2023. The outcome measures included lesion background, en bloc resection rate, en bloc complete resection rates, and incidence of adverse events (including post-operative bleeding, intraoperative perforation, and delayed perforation). RESULTS: The lesions in the esophagus, stomach, and duodenum were eight, three, and three, respectively, and the median length (range) of each located lesion was 16.5 (6-26), 17 (9-36), and 10 (4-16) mm, respectively. En bloc resection and en bloc complete resection rates were 100 and 92.9%, respectively. The only adverse event was an intraoperative perforation observed during duodenal ESD, resulting from the assistant's inadvertent expansion of the SOUTEN at the final dissection stage. CONCLUSION: Our results demonstrate that ESD with an ultrathin endoscope effectively reaches lesions in difficult locations and enables treatment within a small working space. Therefore, ESD using an ultrathin endoscope is a treatment option for lesions located distally to gastrointestinal stenosis, highly fibrotic lesions, and duodenal tumors.

Far-East Asian Toxoplasma isolates share ancestry with North and South/Central American recombinant lineages.

Toxoplasma gondii is a global protozoan pathogen. Clonal lineages predominate in Europe, North America, Africa, and China, whereas highly recombinant parasites are endemic in South/Central America. Far East Asian T. gondii isolates are not included in current global population genetic structure analyses at WGS resolution. Here we report a genome-wide population study that compared eight Japanese and two Chinese isolates against representative worldwide T. gondii genomes using POPSICLE, a novel population structure analyzing software. Also included were 7 genomes resurrected from non-viable isolates by target enrichment sequencing. Visualization of the genome structure by POPSICLE shows a mixture of Chinese haplogroup (HG) 13 haploblocks introgressed within the genomes of Japanese HG2 and North American HG12. Furthermore, two ancestral lineages were identified in the Japanese strains; one lineage shares a common ancestor with HG11 found in both Japanese strains and North American HG12. The other ancestral lineage, found in T. gondii isolates from a small island in Japan, is admixed with genetically diversified South/Central American strains. Taken together, this study suggests multiple ancestral links between Far East Asian and American T. gondii strains and provides insight into the transmission history of this cosmopolitan organism.

Outcomes of 11 dogs with short radius syndrome treated with acute arthroscopically assisted ulnar shortening.

OBJECTIVE: To describe the short-term outcome of acute arthroscopically assisted ulnar shortening (AUS), to treat short radius syndrome in dogs. STUDY DESIGN: Case series. ANIMALS: Eleven client owned dogs. METHODS: Records of dogs that had undergone AUS for treatment of short radius syndrome were reviewed for inclusion. Reporting data included among others pre- and postoperative radioulnar, humeroradial and humeroulnar distances, lameness scores, surgical times, complications and clinical outcome. RESULTS: Following AUS, radiohumeral articulation was improved in all dogs. Median presurgery radioulnar, humeroradial and humeroulnar values were 4.5, 3.2, and 2.2 mm and were improved with surgery by a median of 3.2, 1.8, and 1.2 mm, respectively. Median surgery time was 140 min. Median time to bone healing was 8 weeks (range: 4-14). Median time to last follow-up was 9 weeks (4-468). Median lameness score (scale 0-4) improved from 2 to 1. No major complications were reported. Short-term clinical outcome was graded by the surgeons as full function in four cases and acceptable function in seven. CONCLUSION AND CLINICAL RELEVANCE: Radiographic and arthroscopic radiohumeral articulation were improved and short-term clinical improvement was documented following AUS in all 11 dogs.

Ultrashort Echo Time Quantitative Magnetic Resonance Imaging of the Cruciate Ligaments in Normal Beagles.

OBJECTIVE: The aim of this study was to provide normative ultrashort echo time magnetic resonance imaging (UTE MRI) data of the patellar ligament (PL), cranial cruciate ligament (CrCL) and caudal cruciate ligament (CdCL) in non-lame Beagles. STUDY DESIGN: Eight stifles from four subjects obtained immediately postmortem were imaged using UTE MRI in the true sagittal plane. Regions of interest were drawn manually and the total (T2*), short T2* (T2*S) and long T2* (T2*L) values of the signal decay were calculated to evaluate the bound and free water components of the tendon. The T2*S, T2*L and T2* values were compared between the PL, CrCL and CdCL RESULTS: The mean and standard deviation of T2*S, T2*L and T2* were as follows: 0.54 ± 0.13, 4.65 ± 1.08 and 8.35 ± 0.82 ms for the PL; 0.46 ± 0.14, 5.99 ± 0.52 and 8.88 ± 0.4 ms for the CrCL and 0.41 ± 0.13, 7.06 ± 0.57 and 9.26 ± 0.18 ms for the CdCL. Significant differences were found between the T2*L component of the PL and each CrCL/CdCL and a smaller difference was noted between the T2*L of the CrCL and CdCL (p = 0.05). No difference of the T2*S value was found between any of the ligaments. CONCLUSION: Establishing normative UTE data of the canine stifle is valuable for comparison in future studies in which normal and damaged ligaments may be evaluated, particularly in those affected limbs in which no instability is identified on physical examination in which normal and damaged ligaments may be evaluated.

Multifactorial assessment of leukocyte reduced platelet rich plasma injection in dogs undergoing tibial plateau leveling osteotomy: A retrospective study.

This study assessed the effects of concurrent intra-articular injection and Tibial Plateau Leveling Osteotomy (TPLO) plate surface treatment with leukoreduced platelet rich plasma (lPRP) on outcomes of dogs undergoing TPLO. A retrospective study of medical records for cases presenting from January 2018 to December 2020 was performed. Client-owned dogs with naturally occurring cranial cruciate ligament rupture that underwent TPLO surgery were divided into two groups. The lPRP group included cases that underwent intra-articular injection and plate surface treatment at the time of their TPLO. The control group (C) underwent TPLO without PRP treatment. Data analyzed included: presence of surgical site infection, implant removal rate, degree of change in OA progression score, lameness score progression and radiographic bone healing. The short- and long-term complication rate, hospitalization and antibiotic therapy were also compared between the groups. Descriptive statistics, comparison analyses (Chi square test, t-test, Fisher's exact test) and multi-level logistic regression models were used for statistical analysis. A total of 110 cases met the study inclusion criteria: 54 = lPRP, 56 = C. There were no significant differences between groups with regard to gender, age, presence of meniscal tear, weight, or body condition score. Significant findings included: improved radiographic healing of the osteotomy in the lPRP group, improved global OA scores in the lPRP group, and improved lameness score at recheck examination in the lPRP group. There was no significant difference between the lPRP and C group with regard to surgical site infection and implant removal rate. Concurrent intra-articular injection and plate surface treatment with leukocyte reduced PRP at the time of TPLO, is beneficial in slowing the progression of OA, hastening the radiographic evidence of osteotomy healing, and improved lameness score on recheck examination. Leukocyte reduced PRP was not a significant factor in reducing SSI or implant removal rate.

Clinical Effect of the C-Reactive Protein to Serum Albumin Ratio in Patients with Metastatic Gastric or Gastroesophageal Junction Cancer Treated with Trifluridine/Tipiracil.

Trifluridine/tipiracil (FTD/TPI) is an oral anticancer agent used as a third- or later-line treatment for patients with metastatic gastric cancer/gastroesophageal junction cancer (mGC/GEJC). The C-reactive protein-to-serum albumin ratio (CAR) is an inflammation-based prognostic marker in gastric cancer. This retrospective study evaluated CAR's clinical significance as a prognostic factor in 64 patients with mGC/GEJC administered FTD/TPI as a third- or later-line therapy. Patients were categorized into high- and low-CAR groups based on pre-treatment blood data. This study evaluated associations between CAR and overall survival (OS), progression-free survival (PFS), clinicopathological features, treatment efficacy, and adverse events. The high-CAR group had significantly worse Eastern Cooperative Oncology Group performance status, a higher prevalence of patients administered with a single course of FTD/TPI, and a higher rate of patients not administered chemotherapy after FTD/TPI therapy than the low-CAR group. Median OS and PFS were significantly poorer in the high-CAR group than in the low-CAR group (113 vs. 399 days; p < 0.001 and 39 vs. 112 days; p < 0.001, respectively). In multivariate analysis, high CAR was an independent prognostic factor for OS and PFS. The overall response rate was not significantly different between the high- and low-CAR groups. Regarding adverse events, the high-CAR group had a significantly lower incidence of neutropenia and a higher incidence of fatigue than the low-CAR group. Therefore, CAR may be a potentially useful prognostic factor for patients with mGC/GEJC treated with FTD/TPI as third- or later-line chemotherapy.

Centerline canine cementless total hip arthroplasty as an alternative implant system; results in 17 dogs (2015-2020).

OBJECTIVE: To evaluate the clinical outcomes associated with the Biomedtrix Centerline canine cementless total hip arthroplasty implant (C-THA). ANIMALS: 17 dogs (20 hips) surgically implanted with C-THA to treat coxofemoral pathology. CLINICAL PRESENTATION AND PROCEDURES: Dogs with C-THA (2015 through 2020) with follow-up of ≥ 6 months were evaluated. Data included signalment, complications, management of complications, radiographs (bone implant interface), and clinical outcomes. Outcomes were assessed radiographically and subjectively via surgeon orthopedic examinations. RESULTS: 15 of 20 (75%) with long term radiographic follow-up had an excellent outcome. 5 hips (25%) had postoperative complications: femoral neck fracture (n = 1; 5%), aseptic loosening (2; 10%), and septic loosening (2; 10%). CLINICAL RELEVANCE: C-THA can restore function in dogs with coxofemoral pathology. This novel procedure showed outcomes comparable to initial reports of other traditional THA implants (cemented, cementless, and hybrid) but complications occurred at a higher rate than recent outcomes of other long-standing THA procedures. Increased case numbers and surgeon experience with this novel implant system may eventually yield results comparable to other accepted THA systems.

Evaluation of Irinotecan and Trifluridine/Tipiracil as Fourth-line Treatments After Third-line Nivolumab for Advanced Gastric Cancer.

BACKGROUND/AIM: Irinotecan and trifluridine/tipiracil (FTD/TPI) are fourth-line treatment options after third-line nivolumab for advanced gastric cancer (AGC). However, the efficacy and safety of irinotecan and FTD/TPI in the fourth-line setting after third-line nivolumab remains unclear. This study aimed to evaluate the efficacy and safety of irinotecan and FTD/TPI in the fourth-line setting after third-line nivolumab. PATIENTS AND METHODS: We identified 137 AGC patients treated with nivolumab as third-line treatment in our institute between October 2017 and July 2021. Of these, we recruited 19 AGC patients who initiated irinotecan and 23 AGC patients who initiated FTD/TPI in the fourth-line setting until September 2021. RESULTS: The median overall survival was 5.83 months for irinotecan and 6.31 months for FTD/TPI. Median time-to-treatment failure was 2.07 months for irinotecan and 1.64 months for FTD/TPI. While the frequency of all-grade diarrhea was higher in irinotecan (36% vs. 17%), grade ≥3 neutropenia tended to be higher in FTD/TPI (21% vs. 35%). CONCLUSION: Irinotecan and FTD/TPI may be clinically useful as fourth-line treatments after nivolumab.

Effects of Oxygen on Lattice Defects in Single-Crystalline Mg2Si Thermoelectrics.

Lattice defect engineering has attracted attention due to its ability to develop thermoelectric materials with low thermal conductivity. For Mg2Si single crystals (SCs), Si vacancy (VSi) defects can be introduced and consequently result in the formation of dislocation cores. These lattice defects confer Mg2Si SCs with a lower thermal conductivity compared to Mg2Si polycrystals. To reveal a mechanism for the stabilisation of VSi in the Mg2Si SCs, we investigated the effects of oxygen (O) on lattice defects by performing electronic structure calculations, secondary ion mass spectrometry, X-ray photoelectron spectroscopy, and photoelectron holography. On the basis of these calculations, we predicted that O stabilised the formation of VSi when it was located at the Si site or at an interstitial site. All experiments confirmed the presence of O inside the Mg2Si SCs. However, O was suggested to be located not at the specific site in the crystal lattice of Mg2Si but at dislocation cores. The interaction between O and the dislocation cores in the Mg2Si SC is expected to immobilise dislocation cores, leading to the stabilisation of VSi formation.

Bi-Deficiency Leading to High-Performance in Mg3 (Sb,Bi)2 -Based Thermoelectric Materials.

Mg3 (Sb,Bi)2 is a potential nearly-room temperature thermoelectric compound composed of earth-abundant elements. However, complex defect tuning and exceptional microstructural control are required. Prior studies have confirmed the detrimental effect of Mg vacancies (VMg ) in Mg3 (Sb,Bi)2 . This study proposes an approach to mitigating the negative scattering effect of VMg by Bi deficiency, synergistically modulating the electrical and thermal transport properties to enhance the thermoelectric performance. Positron annihilation spectrometry and Cs -corrected scanning transmission electron microscopy analyses indicated that the VMg tends to coalesce due to the introduced Bi vacancies (VBi ). The defects created by Bi deficiency effectively weaken the scattering of electrons from the intrinsic VMg and enhance phonon scattering. A peak zT of 1.82 at 773 K and high conversion efficiency of 11.3% at ∆T = 473 K are achieved in the optimized composition of Mg3 (Sb,Bi)2 by tuning the defect combination. This work demonstrates a feasible and effective approach to improving the performance of Mg3 (Sb,Bi)2 as an emerging thermoelectric material.

Clinical Significance of Neutrophil-to-Lymphocyte Ratio/Serum Albumin Ratio in Patients With Metastatic Gastric or Gastroesophageal Junction Cancer Administered Trifluridine/Tipiracil.

BACKGROUND/AIM: Trifluridine/tipiracil (FTD/TPI) is an anticancer-agent that is administered as third-line or later chemotherapy for metastatic gastric/gastroesophageal junction cancer (mGC/GEJC). Although inflammatory and nutritional statuses have attracted attention as prognostic factors for patients with mGC/GEJC in this therapy, their usefulness has not been fully clarified. Thus, this study investigated the clinical significance of prognostic nutritional index (PNI), neutrophil/lymphocyte ratio (NLR), and NLR/serum albumin (Alb) ratio in patients administered FTD/TPI. PATIENTS AND METHODS: This retrospective study included 64 patients who underwent FTD/TPI treatment for mGC/GEJC at Kanagawa Cancer Center, Kanagawa, Japan, between October 2019 and June 2022. Patients were divided into high and low PNI, NLR, and NLR/Alb groups according to their pretreatment blood data. This study evaluated the associations between the inflammatory and nutritional indexes and survivals. RESULTS: Overall survival (OS) and progression-free survival (PFS) of patients with low PNI were significantly poorer than those with high PNI. However, low PNI was not an independent prognostic factor for OS and PFS. There was no significant association between NLR and OS or PFS. In contrast, the OS of patients with high NLR/Alb was significantly poorer than those with high PNI and low NLR/Alb. Furthermore, multivariate analysis showed that high NLR/Alb was an independent prognostic factor for OS. CONCLUSION: The NLR/Alb may be a useful prognostic factor in patients with mGC/GEJC being administered FTD/TPI as third-line or later chemotherapy.

Age and Sex Comparison of the Canine Supraspinatus Tendon Using Quantitative Magnetic Resonance Imaging T2 Mapping.

OBJECTIVE: The normal canine supraspinatus tendon has properties commonly attributed to damage such as core hyperintensity and increased width. Little is published regarding the normal tendon, including how senescent changes and sex differences may affect the appearance. Conventional magnetic resonance imaging (MRI) techniques provide subjective analysis of tendons based on observer assessment of signal intensity and appearance. Quantitative MRI (qMRI) techniques such as T2 mapping provide an objective comparison of collagen orientation with analysis of a decay constant, T2. This study investigates age and sex related changes in the canine supraspinatus tendon using the qMRI technique of T2 mapping. STUDY DESIGN: In this study, 34 tendons of clinically sound male and female dogs (0.6-13 years) were imaged using qMRI T2 mapping techniques. Sagittal plane T2 maps of the supraspinatus tendon were depth-normalized, and profiles compared using two separate four-parameter logistic equations describing T2 mapping profiles as sigmoidal curves. Combined parameters evaluated included range of T2 values, curve steepness, vertical curve shift, lower bound of T2, upper bound of T2 and horizontal curve shift. RESULTS: A significant reduction in the most central portion of the supraspinatus tendon was found for every increased year in age (-1.56 ± 0.47 milliseconds [-2.56, -0.56, p = 0.004]). No significant difference in curve parameters was found between sexes. CONCLUSION: The reduction in T2 with age suggests a senescent change may be anticipated with the canine supraspinatus tendon.

MORPHOLOGIC OBSERVATION AND FIRST MOLECULAR CHARACTERIZATION OF ENCYCLOMETRA JAPONICA (DIGENEA: ENCYCLOMETRIDAE) IN THE DIGESTIVE TRACT OF WILD TIGER KEELBACKS (RHABDOPHIS TIGRINUS) IN JAPAN.

Encyclometra japonica Yoshida and Ozaki, 1929 is a fluke that parasitizes the digestive tract of snakes. When the species was first reported, it was originally characterized on the basis of morphologic features, namely, the characteristics of the 2 testes located obliquely in the anterior-posterior direction, and the position of the ventral sucker one-fourth to one-third from the anterior extremity. Thereafter, more specimens with other morphologic variations were reported, and a new morphologic feature for species discrimination was proposed. However, the proposal is uncertain, and the criteria for morphologic discrimination between E. japonica and other Encyclometra species remain debatable. Thus, morphologically discriminable characteristics on the basis of a sufficient number of specimens are required, and molecular methods for species identification that allow for a more objective assessment need to be established. Therefore, in the present study, nucleotide sequences of 18S, 28S ribosomal deoxyribonucleic acid and cytochrome c oxidase subunit I (COI) of E. japonica were determined along with detailed morphologic observations for the first time. Key characteristics were observed in all specimens, whereas some morphologic variations were observed in the symmetry of the cecum. The COI sequences, which are known to be variable genetic regions, were identical among all specimens; therefore, all of them were considered the same species. This result clarifies the high morphologic variation in E. japonica. The 18S and 28S sequences were 99.78% and 99.11-99.19% similar to those of Encylometra colubrimurorum. The high degree of homology between these genes indicates that E. japonica and E. colubrimurorum are closely related but independent species. The present data will be used for the identification of E. japonica and to evaluate the relationships within the genus Encyclometra.

Relevance of Solidification Kinetics for Enhanced Thermoelectric Performance in Al-Doped Higher Manganese Silicides.

The solidification kinetics of an alloy from its liquid state forms an underlying basis for microstructural engineering, wherein the state of thermodynamic equilibrium associated with the melt-grown crystal and the quenched amorphous solid denotes the two limits for crystallinity in the alloy synthesis. In this study, we report the implication of the crystalline state on the thermal and electrical transport properties of partially substituted Mn(Si1-xAlx)γ by comparing the single crystals melt-grown by the Bridgman method, and polycrystals synthesized from melt spinning (MS) and subsequent spark plasma sintering (SPS). The rapidly solidified alloys exhibited nanocrystalline microstructures in MS ribbons, while melt-grown single crystals displayed characteristics evolution of MnSi striations with limited solubility of Al. It was observed that Al as a p-type dopant enhances the carrier concentration and electrical conductivity, while nanocrystallinity in MS + SPS polycrystals and secondary phases in monocrystals were effective in enhancing the phonon scattering. Maximum zT values of ∼0.54 (±0.05) at 823 K and 0.75 (±0.05) at 873 K were attained for the single crystal (directed perpendicular to the c-axis) and melt-spun polycrystals (along the in-plane direction), respectively. These results present the efficacy of aliovalent Al substitution and demonstrate the critical role of the solidification kinetics in optimizing the carrier concentration and enhancing the phonon scattering in higher manganese silicide crystals for thermoelectric applications.

Dispersal direction of Malaysian Fasciola gigantica from neighboring southeast Asian countries inferred using mitochondrial DNA analysis.

Fasciola gigantica and hybrid Fasciola flukes, responsible for the disease fasciolosis, are found in Southeast Asian countries. In the present study, we performed molecular species identification of Fasciola flukes distributed in Terengganu, Malaysia using multiplex PCR for phosphoenolpyruvate carboxykinase (pepck) and PCR-restriction fragment length polymorphism (RFLP) for DNA polymerase delta (pold). Simultaneously, phylogenetic analysis based on mitochondrial NADH dehydrogenase subunit 1 (nad1) was performed for the first time on Malaysian Fasciola flukes to infer the dispersal direction among neighboring countries. A total of 40 flukes used in this study were identified as F. gigantica. Eight nad1 haplotypes were identified in the F. gigantica population of Terengganu. Median-joining network analysis revealed that the Malaysian population was related to those obtained from bordering countries such as Thailand and Indonesia. However, genetic differentiation was detected using population genetics analyses. Nevertheless, the nucleotide diversity (π) value suggested that F. gigantica with the predominant haplotypes was introduced into Malaysia from Thailand and Indonesia. The dispersal direction suggested by population genetics in the present study may not be fully reliable since Fasciola flukes were collected from a single location in one state of Malaysia. Further studies analyzing more samples from many locations are required to validate the dispersal direction proposed herein.

Population structure, molecular characterization, and phylogenetic analysis of Fasciola gigantica from two locations in Uganda.

Fasciola gigantica is a major pathogen that causes fasciolosis in Africa. A recent study in Uganda demonstrated that Fasciola flukes were present in 65.7% of slaughtered cattle. However, molecular identification of Fasciola species has not yet been performed in the country. In the present study, 292 Fasciola flukes were collected from Kampala and Gulu, Uganda. The samples were identified as F. gigantica using a multiplex polymerase chain reaction (PCR) assay for phosphoenolpyruvate carboxykinase (pepck) and a PCR-restriction fragment length polymorphism (RFLP) assay for DNA polymerase delta (pold). A significant genetic difference between F. gigantica obtained from cattle slaughtered at Kampala and Gulu was observed by analyzing the mitochondrial markers NADH dehydrogenase subunit 1 (nad1) and cytochrome C oxidase subunit 1 (cox1). Fasciola collected from Gulu had a more diversified population than that collected from Kampala, probably because of differences in livestock management systems. One of the possible reasons for this observation is that cattle slaughtered in Gulu were reared under an extensive communal grazing system, which is suitable for maintaining parasite diversity, whereas cattle slaughtered in Kampala mainly originated from fenced/closed farms, which limits parasite diversity. However, the cause of the difference between these two locations was not clearly defined by the results of this study. The F. gigantica population from Uganda was related to that obtained from Zambia. A star-like phylogeny was detected in a median-joining network analysis, which indicated rapid population expansion and suggested that the F. gigantica populations from both countries are maintained by domestic ruminants in eastern Africa. Interestingly, the F. gigantica population from Uganda was not related to those from Egypt and Nigeria. The results of the present study suggest that F. gigantica populations in African countries are indigenous to each country or region.