Parasitology Research最新文献

Opisthorchiasis, caused by the liver fluke Opisthorchis viverrini, is endemic to Southeast Asian countries and constitutes a major health problem as it increases the risk of cholangiocarcinoma. However, owing to the complicated life cycle of O. viverrini, there is no rapid method for monitoring the risk of infection in the environment. The inability to identify water sources at risk of infection presents a challenge in implementing preventive measures in areas where fish are a significant component of the local diet. Using the environmental DNA (eDNA) approach to detect parasitic DNA in water samples, it is possible to understand the distribution of O. viverrini and the dynamics of infection with high accuracy. However, the sensitivity of environmental samples remains a bottleneck. In this study, we developed a highly sensitive method for detecting O. viverrini eDNA by designing a multi-marker assay targeting two mitochondrial and two nuclear genes. We compared its performance with single-marker assays using tissue-derived DNA. The multi-marker assay exhibited the highest detection sensitivity. We also collected data from 56 sites in Sakon Nakhon, Thailand, in October 2022, and tested them for eDNA detection of O. viverrini. Eleven sites were positive in the multi-marker assay, whereas five sites were positive in the single-marker assay. This multi-marker assay can be used in the field to detect small organisms and rare species, other than parasites, that are expected to have low levels of eDNA.

Toxoplasmosis is a foodborne zoonotic parasitic disease caused by Toxoplasma gondii, which seriously threatens to human health and causes economic losses. At present, there is no effective vaccine strategy for the prevention and control of toxoplasmosis. T. gondii rhoptry proteins (ROPs) are important proteins secreted by the parasite during the early stage of invasion into host cells. In this study, we constructed six individual plasmids (pVAX1-ROP2, pVAX1-ROP5, pVAX1-ROP9, pVAX1-ROP16, pVAX1-ROP17, and pVAX1-ROP18) encoding T. gondii rhoptry proteins and then used an equimolar amount of each as a vaccine cocktail. Following booster immunization, serum antibody levels, splenic lymphocyte proliferation, cytokine production, and survival time after infection with T. gondii RH strain were measured in immunized mice. The results showed that the mice immunized with the DNA vaccine cocktail developed a higher level of the specific anti-T. gondii IgG in serum and the cytokines such as IFN-γ, IL-2, IL-12, and IL-4 (P < 0.01). The stimulation index (SI) of spleen lymphocytes (P < 0.01), the frequencies of CD4⁺ T lymphocytes (P < 0.01), and the ratio of CD4⁺/CD8⁺ T lymphocytes (P < 0.05 or P < 0.01) in the vaccine-immunized mice were significantly increased compared to the control group. After challenge with the virulent T. gondii RH strain tachyzoites, the survival time of mice in the DNA vaccine cocktail group (18.1 ± 1.81 d) was significantly longer (P < 0.01) than that in the control group (8.4 ± 1.02 or 7.9 ± 0.83 d). The results indicated that the DNA vaccine cocktail could elicit strong humoral and cellular immune responses in mice and could also improve the resistance of mice to acute T. gondii infection.

This is the first study that targets the epidemiology of Gasterophilus spp. in slaughtered horses from Romania. Previously to our research, there were five recorded species: Gasterophilus haemorrhoidalis, Gasterophilus inermis, Gasterophilus intestinalis, Gasterophilus nasalis, and Gasterophilus pecorum with a dispersed distribution throughout the country, the data being recorded more than 73 years ago. The collection of Gasterophilus larvae was carried out from the digestive system (stomach, duodenum, and rectum) of horses in three abattoirs, monthly between January 2023 and December 2023. Following dissection, all larvae were stored in absolute ethanol until morphological and molecular identification. The larvae were counted and identified according to morphological keys. Overall, 394 horses were examined, of which 211 (53.6%) were infected with L2 or L3 of Gasterophilus spp. Only two species were found: G. intestinalis (prevalence 52.0%) and G. nasalis (14.0%). Coinfection with both species occurred in 49 horses (12.4%). In total, 9759 larvae were collected (7916 L3 and 1843 L2). Larvae were localized in the stomach (G. intestinalis) and duodenum (G. nasalis) of horses. There was a strong seasonal variation in the mean intensity and mean abundance for both G. intestinalis and G. nasalis larvae and also for coinfections (p < 0.05). There were no significant differences between prevalence and mean intensity across gender, group age, or horse colour. Our findings show that Gasterophilus infection is widespread within Romania territory, being a possible cause of illness and welfare issues in horses.

Strongyloides stercoralis and Opisthorchis viverrini are helminth parasites responsible for significantly neglected tropical diseases. This study aimed to evaluate the prevalence of these parasites and the risk factors for S. stercoralis and O. viverrini infections in northern and northeastern Thailand where relevant epidemiological data are scarce and outdated. A cross-sectional study was conducted in 2016 in six sub-districts across five provinces. Urine samples were analyzed to detect S. stercoralis and O. viverrini infection using urine enzyme-linked immunosorbent assays (urine-ELISA). Demographic data of participants were collected using a questionnaire. Environmental data, including land-surface temperature (LST), normalized difference vegetation index (NDVI), normalized difference water index (NDWI), and soil pH, were obtained from remote-sensing sources. Multiple logistic regression analysis identified risk factors associated with infection. Complete data were obtained for 2613 individuals. The overall prevalence was 39.15% (95% CI: 37.27-41.02) for S. stercoralis and 37.46% (95% CI: 35.61-39.32) for O. viverrini. Male sex was significantly associated with S. stercoralis (AOR, 1.53; 95% CI, 1.29-1.80, p < 0.001) and O. viverrini infections (AOR, 1.69; 95% CI, 1.43-2.00, p < 0.001). The prevalence of S. stercoralis infection increased with age. Spatially, the odds of S. stercoralis infection decreased with higher LST and soil pH, while O. viverrini infection was associated with higher soil pH and proximity to water bodies. Strongyloides stercoralis and O. viverrini are highly prevalent in these regions, highlighting the need for surveillance.

Pluripotent somatic stem cells are the drivers of unlimited growth of Echinococcus multilocularis metacestode tissue within the organs of the intermediate host. To understand the dynamics of parasite proliferation within the host, it is therefore important to delineate basic mechanisms of Echinococcus stem cell maintenance and differentiation. We herein undertake the first step towards characterizing the role of an evolutionarily old metazoan cell-cell communication system, delta/notch signalling, in Echinococcus cell fate decisions. Bioinformatic analyses revealed that all central components of this pathway are encoded by the Echinococcus genome and are expressed in parasite larval stages. By in situ hybridisation, we analyzed the expression patterns of clearly identified delta-like ligands, delta1 and delta2, as well as two notch receptors, notch1 and notch2, in metacestode tissue. Except for delta1, which is not expressed in the metacestode, all other components are expressed in distinct cells throughout the parasite's germinal layer. Combined in situ hybridisation and EdU incorporation experiments together with pulse-chase assays further indicate that delta2, notch1, and notch2 are exclusively expressed in post-mitotic cells. Echinococcus asymmetric stem cell division, leading to the progeny of different fates, therefore most probably not involves delta/notch signalling components. Our analyses are relevant for understanding the interplay of fate-determining signalling pathways in Echinococcus cell differentiation and form a basis for further experiments into the role of delta/notch signalling in parasite development.

Piroplasmosis is an important tick-borne disease in several regions, and can lead to significant economic animal production losses. The current study aimed to systematically examine the incidence of bovine piroplasmosis in Kashgar, Xinjiang, to provide baseline data for the effective prevention and control of this disease among bovines in the region. A total of 1403 bovine blood samples from 12 sampling points were screened via PCR with universal Piroplasma primers targeting the 18S rRNA locus and specific Theileria annulata primers targeting the cytochrome b (COB) gene. The overall prevalence of bovine Piroplasma was 65.9% (925/1403). Three species of pathogenic Theileria, including T. annulata, T. orientalis, and T. sinensis, were detected, and the infection rates for these species were 65.1% (913/1403), 0.5% (7/1403), and 0.1% (1/1403), respectively. The mixed infection rate for T. orientalis and T. annulata was 0.3% (4/1403). No Babesia was detected in this study. In conclusion, bovine piroplasmosis was still common in Kashgar and T. annulata was the dominant species, and a mixed infection of T. annulata and T. orientalis was detected. Notably, T. sinensis was reported for the first time in this region. Therefore, strategies for the prevention and control of bovine piroplasmosis should be enhanced.

Clonorchiosis, a disease that develops following the consumption of raw freshwater fish that harbors Clonorchis sinensis metacercariae, seriously threatens the health of residents in endemic areas. We aimed to assess the level of awareness of liver fluke infections among infected residents and restaurant workers in liver fluke infection-endemic areas. To identify and provide a more realistic description of C. sinensis infections, we conducted a focused interview and questionnaire survey of local residents in endemic areas in Korea. Most residents knew that freshwater fish are a source of C. sinensis infection. Nevertheless, the consumption of raw freshwater fish was the main risk factor for their infection with C. sinensis. The residents had little knowledge regarding their residential area being endemic to C. sinensis or about the symptoms and complications of C. sinensis infection. Although the participants had no experience with C. sinensis prevention or health education, they preferred on-site education during visits to village halls. The in-depth interviewees had a high level of knowledge about C. sinensis infection but were unaware that eating raw freshwater fish was its cause. Family and social gatherings encourage the habit of eating raw freshwater fish, which is a risk factor for repetitive infections. Based on these findings, to eliminate clonorchiosis, we propose strengthening the capacity of public health care personnel, giving C. sinensis prevention education, and screening educational videos during visits to village halls. Furthermore, intensive education is recommended for reinfected people and community opinion leaders, as well as reservoir host control.

ATP-binding cassette (ABC) transporter proteins, one of the largest families of membrane transport proteins, participate in almost all biological processes and widely exist in living organisms. Microsporidia are intracellular parasites; they can reduce crop yields and pose a threat to human health. The ABC proteins are also present in microsporidia and play a critical role in their proliferation and energy transport. In this study, a novel ABC transporter protein of Nosema bombycis named NoboABCG1.3 was identified. The NoboABCG1.3 protein is comprised of 640 amino acids, which contain six transmembrane domains and one nucleotide-binding domain. After N. bombycis infection of cells or tissues, quantitative reverse transcription polymerase chain reaction analysis revealed a progressive elevation in the transcript levels of NoboABCG1.3. Downregulation of NoboABCG1.3 expression significantly inhibited N. bombycis proliferation. Subsequently, a transgenic cell line stably expressing an interfering fragment of NoboABCG1.3 was established, which exhibited extreme inhibition on the proliferation of N. bombycis. These findings indicate that NoboABCG1.3 plays a role in the proliferation of N. bombycis and holds promise as a target for developing N. bombycis-resistant silkworms.

Dirofilaria immitis is a zoonotic vector-borne parasite that causes heartworm disease most commonly in canines. Although present in the Caribbean, no published work exists from Jamaica. Therefore, the aim of our study was to evaluate the prevalence of D. immitis in Jamaica. From June to December 2022, whole blood samples from 1000 dogs were collected from all parishes and tested using the Bionote Canine Heartworm Antigen Test Kit 2.0. Dogs that were at least 6 months old, privately owned, residing in shelters, working in the security sector, or strays were recruited into the study. Details on the breed, known or approximate age, sex, use of heartworm prophylaxis, and other medications and location of animals were provided by owners/authorizing agents and recorded. Test results were available for 986 dogs of which 184 tested positive, with an overall prevalence of 18.7% (95% CI, 16.28 to 21.24). Mature adults (2-6 years) comprised most of our sampled population (46.7%), followed by early seniors (7-9 years) (20.1%) and young adults (13-24 months) (9.9%). Prevalence for those age groups was 21.9%, 19.5%, and 7.1%, respectively. A seropositivity of 25.1% was seen in dogs not on heartworm preventative medication compared to 5.5% of dogs on heartworm preventative medication. Our study highlights a higher seroprevalence of D. immitis infections in older dogs and provides evidence supporting the use of preventive medication in the country.

European sardine Sardina pilchardus is a commercially valuable coastal pelagic fish species. Spain is one of the largest sardine suppliers in Europe and the Iberian stock is of particular significance. Kudoa parasites are known to infect sardines causing the so-called 'soft flesh' condition; however, data on the occurrence of 'soft flesh' in this sardine stock are limited. This study investigates the occurrence of Kudoa-induced 'soft flesh' in the Iberian sardine stock caught in 2023 off the northern Spanish Atlantic coast (Division 8.c). Five hundred specimens were examined for 'soft flesh' by manual texture testing and visual inspection 48 h post-catch using standardized procedures. 'Soft flesh' was detected in 5.4% (27/500) of the sardines. Microscopic examination of muscle samples revealed the presence of Kudoa thyrsites-like myxospores in all 'soft flesh'-affected fish, which based on SSU rDNA gene sequence analysis was identified as K. thyrsites. The unsightly appearance of infected fillets represents a substantial food quality issue for the Iberian sardine stock that could reduce marketability and consumer confidence in both local and international markets. This is particularly relevant since larger Iberian sardines, which are highly appreciated by consumers, appear to be the most affected.