Parasite最新文献

The "One Health" concept, emphasizing the interdependence of human, animal, and ecosystem health, has gained renewed global attention and institutional support from the World Health Organization, Food and Agriculture Organization of the United Nations, United Nations Environment Program, and World Organization for Animal Health. Here we underline that some principles of parasitology are embedded in this concept. As early as the 19th century, Rudolf Virchow affirmed the unity of human and veterinary medicine, a vision long practiced by parasitologists through their multidisciplinary work on zoonotic diseases. The classical "One Health" triad (humans, animals, and ecosystems) closely mirrors the complex life cycles of many parasitic zoonoses, where distinct stages circulate among hosts and ecosystems. Parasitology societies worldwide have fostered collaboration among scientists, veterinarians, physicians, and other professionals, embodying some aspects of the "One Health" approach well before its formal recognition. Using cysticercosis as an example, this article illustrates how a multisectoral, integrated framework could support effective disease control. We argue that implementing a comprehensive "One Health" strategy to combat parasitic diseases requires a systemic approach that encompasses not only veterinary and human medicine, but also ecology, the social sciences, and economics. This approach must explicitly consider research objectives related not only to human and animal health, but also to ecosystem health.

Entomological parameters such as mosquito biting rates often fail to capture variability in human behavior, thereby limiting its accuracy for assessing the population-level malaria risk. This study investigated the use of previously described Anopheles gambiae-based anti-salivary biomarker, anti-gSG6-P1, as a serological marker for Anopheles exposure, and examined key entomological, human, and environmental risk factors in Sisaket Province, Thailand. Blood samples were collected via finger prick from the same set of 184 participants across three seasons: rainy (August 2022), cool-dry (December 2022), and hot-dry (April 2023). Anti-gSG6-P1 IgG levels were quantified using ELISA. Factor Analysis of Mixed Data revealed that seasonality exerted the strongest influence on anti-gSG6-P1 IgG levels, which was likely driven by human activities, particularly the frequency of rubber tapping activity in the areas where Anopheles dirus is present. A higher frequency of rubber plot entry (5-7 days/week) significantly increased anti-gSG6-P1 IgG responses (1.08 ± 0.36) compared with the lower frequency group (0-4 days/week) (0.96 ± 0.35). Furthermore, our findings revealed the complex interplay between anti-gSG6-P1 IgG levels and the seasonality of human behavioral and vector dynamics. These factors highlight key limitations of the anti-gSG6-P1 IgG biomarker in the Greater Mekong Subregion, particularly the lack of well-characterized anti-gSG6-P1 IgG serological response kinetics in regions where predominant vector species exhibit low salivary peptide homology to An. gambiae. These findings emphasize the need for new serological tools tailored to malaria vector species present in the Subregion to improve malaria risk assessment and strengthen vector control strategies.

Canine sarcoptic mange, caused by Sarcoptes scabiei, is a highly contagious and intensely pruritic skin disease in dogs. It is prevalent worldwide and has zoonotic potential. Therefore, effective treatment is important to safeguard animal welfare and public health. The present clinical field study aimed to confirm the efficacy of NexGard^® Plus, an oral combination of afoxolaner, moxidectin and pyrantel pamoate, in treating dogs naturally infested with S. scabiei. It was a blinded, randomised, single-centre, negative-controlled efficacy study. Twenty naturally infested dogs were allocated into two groups: a group treated on Day 0 and Day 26/28 at the label dose, and an untreated control group. Skin scrapings were conducted similarly, once between Day -6 to 0, then on Days 26/28 and 56 for mite counts. Assessments of clinical signs were conducted at the same time intervals. In the treated group, mite infestations were reduced by 97% after the first treatment and were eliminated (100%) after the second treatment (p < 0.0005), while all dogs in the untreated control group remained infested for the whole study. Treated dogs had no pruritus, papules or crusts and clear evidence of hair regrowth by Day 56, unlike the dogs in the control group. This study demonstrated the elimination of S. scabiei mites and significant improvement of sarcoptic mange clinical signs in naturally infested dogs treated with the oral combination of afoxolaner, moxidectin and pyrantel.

Toxoplasma gondii is an intracellular protozoan parasite known to infect a wide range of hosts, including humans, and is a significant cause of health issues, particularly in pregnant women and immunocompromised individuals. However, it has garnered attention for its potential in cancer treatment due to its diverse anti-cancer mechanisms. Toxoplasma gondii induces key cytokines such as IL-12 and IFN-γ, triggering robust Th1 immune responses that effectively target tumor cells. Furthermore, it modulates the immunosuppressive tumor microenvironment (TME), reduces inhibitory immune cells, promotes activated immune cells, induces apoptosis in tumor cells, inhibits proliferation, and disrupts tumor angiogenesis through regulatory signaling pathways. Despite these promising antitumor attributes, significant limitations hinder its translation into clinical practice. These include strain-dependent differences in virulence and therapeutic efficacy, ethical and biosafety concerns associated with wild-type strains, limited applicability of animal data to human therapy, and the possibility that the parasite may promote tumorigenesis under certain conditions. Innovative approaches such as engineered strains for precise tumor targeting, exploitation of its bioactive agents, use as a drug carrier for brain tumors, and combination therapies with other anti-cancer modalities show promise. These advances, coupled with comprehensive cost-effectiveness assessments, present new opportunities and hope for integrating T. gondii into cancer therapy.

In the tropical savannahs with long dry seasons, malaria mosquito populations virtually disappear after the drying up of breeding sites to reappear in large numbers at the onset of next rainy season. While aestivation and long-distance migration are proposed as key strategies enabling these vectors to persist through the dry-season, the physiological, biochemical, and morphological traits underpinning these mechanisms remain insufficiently explored, particularly under natural field conditions. This study explored seasonal changes in Anopheles coluzzii, An. gambiae, and An. arabiensis at the onset of the dry season in the harsh savannahs of Burkina Faso, West Africa. Late-instar immature specimens were collected from two ecologically distinct sites, one with permanent and the other with only temporary breeding habitats, during the rainy season and the transitional period into the dry season. Larvae were reared to adulthood under natural conditions and several traits were analysed including ovarian development, sub-cuticular fat body hypertrophy, body size, and energy reserves. Gonotrophic dissociation was significantly more frequent in An. coluzzii at the onset of the dry season, indicating a shift toward reproductive arrest. All three species exhibited increased body size and cuticular fat deposits during the transitional period, though with species-specific differences. Notably, only An. coluzzii showed significant increases in energy reserves (proteins, lipids, and carbohydrates) during the transition period. These adaptive responses differed between the study sites, suggesting the influence of breeding habitats. The findings highlight that species within the An. gambiae complex engage in distinct phenotypic trajectories at the onset of the dry season, suggesting divergent adaptations and trade-offs in energy acquisition and allocation to survive during the dry season.

This study aimed to evaluate the diagnostic and analytical performance of OvaCyte, an automated image-based system for the detection of gastrointestinal parasites in ruminants, against traditional flotation techniques. OvaCyte is available in two versions: OvaCyte Plus, which automates egg detection and quantification, and OvaCyte Premium, which incorporates enhanced analysis to differentiate parasite families, genera, and species within strongyles (e.g., Trichostrongylidae, Haemonchus contortus, and Nematodirus spp.). Coccidia are also classified as standard or type B, with the latter specifically including Eimeria weybridgensis, Eimeria crandallis and Eimeria ovinoidalis, based on distinct morphometrical features. The identification of Haemonchus contortus was validated using peanut agglutinin (PNA) fluorescence staining as the gold standard. Sensitivity and specificity for OvaCyte Plus, Mini-FLOTAC, and McMaster were calculated based on a consensus "true status". Limits of detection and quantification were calculated using regression analysis. OvaCyte Plus demonstrated the highest sensitivity, especially for Nematodirus (95%), coccidia (93%), strongyles (92%), and Strongyloides papillosus (90%). Mini-FLOTAC showed moderate sensitivity (63-79%), while McMaster had the lowest value (30-76%). For Moniezia spp., sensitivity was similar for OvaCyte Plus and Mini-FLOTAC (79%), but lower for McMaster (59%). Specificity was high across all techniques (92-100%). Differences in performance were attributed to varying multiplication factors: OvaCyte Plus (3 EPG), Mini-FLOTAC (7.5 EPG), and McMaster (50 EPG). Strong correlations were observed between OvaCyte Plus and manual techniques for strongyle egg counts. OvaCyte Premium exhibited the highest sensitivity across all parasites. OvaCyte Plus and Premium demonstrated performance comparable to or exceeding traditional techniques for the detection of gastrointestinal parasites in ruminants.

Human cysticercosis is a serious zoonosis caused by infection with larvae (cysticerci) of the pork tapeworm, Taenia solium. Infection can involve the nervous system, causing chronic headache and intracranial hypertension, focal neurological deficits, epileptic seizures, and paralysis. The disease is found in developing countries, where porcine cysticercosis is prevalent and undercooked pork is habitually consumed. This study aimed to develop immunochromatography-based test (ICT) kits, using low-molecular-weight antigens purified from cyst fluids of Latin American and Asian genotypes of T. solium. To evaluate the kits, we used 164 serum samples, including 24 from proven/confirmed cysticercosis cases, 110 from cases with other parasitoses, and 30 from healthy individuals. Diagnostic performances were calculated. The sensitivity, specificity, and accuracy were 83.3% (95% CI [62.6-95.3]), 93.6% (95% CI [88.1-97.0]), and 92.1% (95% CI [86.8-95.7]), respectively for the American genotype-based ICT kit, while for the Asian genotype-based ICT kit, they were 87.5% (95% CI [67.6-97.3]), 98.6% (95% CI [94.9-99.8]), and 97.0% (95% CI [93.0-99.0]), respectively. The sensitivity and specificity did not significantly differ between the two ICT kits (exact McNemar's test; p > 0.05), with a concordance of 93.9%, represented by a Cohen's kappa of 0.77 (p < 0.001), indicating substantial agreement. These results indicate that affinity-purified antigens from different geographical isolates can be used for the diagnosis of human cysticercosis. The diagnostic specificities were better than for a previously reported ICT kit that used crude antigen.

Human African trypanosomiasis (HAT) and Animal African trypanosomiasis (AAT), transmitted by Glossina species, remain major health and economic burdens in Africa. Accurate vector identification is essential for effective control strategies. However, current identification methods of Glossina species based on morphological and/or molecular techniques have several limitations that often hinder reliable species-level classification. This study assessed matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) as an alternative or complementary approach to morphological and molecular methods for Glossina species identification and explored its ability to detect infection status. A total of 265 tsetse flies were collected and morphologically classified into the Glossina palpalis group (n = 200) and the Glossina fuscipes group (n = 65), later confirmed by molecular analysis as Glossina palpalis palpalis and Glossina fuscipes quanzensis, respectively. Spectra were generated from wings, legs, and thoraxes to identify the most suitable body parts. For G. p. palpalis, high-quality spectra were obtained from wings (98.0%), legs (96.5%), and thoraxes (93.5%); for G. f. quanzensis, corresponding values were 89.2%, 87.7%, and 72.3%. Blind testing showed that 89.5% of spectra for G. p. palpalis and 95.2% for G. f. quanzensis matched morphological identification, with 87.0% and 94.6%, respectively, reaching relevant score thresholds. Molecular screening detected Trypanosoma congolense DNA in nine specimens, but MALDI-TOF MS spectra could not distinguish infected from uninfected flies. These findings demonstrate that MALDI-TOF MS is a rapid, reliable tool for Glossina species identification, particularly using wings and legs, but is unsuitable for infection status determination.

Parthenogenic Fasciola (Trematoda: Fasciolidae) flukes have been developed by the hybridization of Fasciola hepatica and Fasciola gigantica. They are aspermic (asF) but capable of clonal expansion through parthenogenesis and are spreading rapidly throughout the globe. Here, we unambiguously prove the occurrence of parthenogenic Fasciola in cattle in Bangladesh, along with their ex vivo culture protocol and anthelmintic efficacy. By employing multiple conventional and molecular tools, we confirmed the presence of both the spermic F. gigantica (sFg) (31.7%; 814/2575) and asF (68.3%; 1761/2575) in Bangladesh. Both the adult sFg and asF survived well in DMEM supplemented with 20% bovine serum and 20% bovine bile. Using a DMEM-based ex vivo culture protocol, we found that nitroxynil (NTX) and oxyclozanide (OCZ) efficiently killed both sFg and asFg in a concentration and time-dependent manner. Surprisingly, triclabendazole (TCBZ) and clorsulon (CRL) killed neither sFg nor asF. Also, praziquantel, albendazole, and levamisole did not affect the viability of the flukes. We found that all TCBZ survivors had more than one mutation, both in nucleotides (G440A, G643A, and G788A) and amino acids (R147K, E215K, and R263K) of the binding pocket of carboxylesterase B (CestB), providing molecular evidence of TCBZ resistance in Fasciola. Taken together, asF constitutes more than two-thirds of the Fasciola population in Bangladesh. This study unambiguously proved the ineffectiveness of TCBZ against both asF and sFg circulating in Bangladesh. Therefore, only OCZ and NTX remain effective against fasciolosis, which thus poses ongoing public health risks of infection in humans with TCBZ-tolerant strains of fasciolosis.

Biting midges of the genus Culicoides Latreille (Ceratopogonidae) pose a significant threat to veterinary health as vectors of over 60 viruses, most of which affect livestock. In this study, we used light traps to sample Culicoides populations on cattle and goat farms from May to October 2023 at 15 sites in Gyeongsangnam-do, Jeollanam-do, and Jeju Island, South Korea. Diversity and abundance were analysed based on the collection date, environmental conditions, and host species. A total of 124,055 individuals were collected, comprising 14 previously recorded and two newly recorded species: C. asiana and C. palawanensis. The dominant species was C. arakawae, which accounted for 80.60% of the total collected individuals, followed by C. punctatus (10.25%), and C. tainanus (3.36%), while the remaining 13 species constituted 5.80% of the collection. Total Culicoides abundance peaked in August (40.15%), driven largely by fluctuations in C. arakawae abundance, but the seasonal abundances of individual species varied. Culicoides arakawae and C. punctatus were dominant on the mainland, while C. matsuzawai, C. lungchiensis, and C. tainanus were dominant on Jeju Island. The dominant species on cattle farms were C. arakawae and C. punctatus, while C. arakawae dominated in collections from goat farms. The detection of two new species records suggests that the fauna of South Korea is still incompletely understood.