Objective Objective To analyze the potential spatial factors affecting the genetic differentiation of Oncomelania hupensis robertsoni in Yunnan Province. Methods A total of 13 administrative villages were selected from schistosomiasis-endemic areas of Yunnan Province as O. hupensis snail sampling sites. At least 200 snails were collected in each site, and the spatial variable data of each site were recorded, including longitude, latitude and altitude. Thirty active and Schistosoma japonicum uninfected O. hupensis snails were selected from each sampling site by means of the crawling method and the cercarial shedding method. Genomic DNA was extracted from O. hupensis snails. Following PCR amplification, purification of PCR amplification products and sequencing, the gene sequences of O. hupensis snail samples were spliced and edited using the DNAstar software and the NCBI database to yield the complete mitochondrial sequences of O. hupensis snails at each sampling site, and the mitochondrial genetic distance matrix of O. hupensis robertsoni was calculated at each sampling site. The geographical coordinates of each sampling site were marked using the software ArcGIS 10.2, and the straight-line geographical distance between each sampling site was calculated. The altitude difference, longitude difference and latitude difference between each sampling site were calculated using the Excel software, and the correlation between the mitochondrial genetic distance matrix of O. hupensis robertsoni and each spatial variable matrix was examined by using the Mantel test at 13 sampling sites in Yunnan Province. Results Among the 13 O. hupensis snail sampling sites in Yunnan Province, the largest mitochondrial genetic distance of O. hupensis robertsoni snail populations was seen between Anding Village, Nanjian Yi Autonomous County and Caizhuang Village, Midu County (26.244 2), and the largest geographical distance was seen between Dongyuan Village, Gucheng District and Cangling Village, Chuxiong County (272.64 km). The highest altitude difference was seen between Anding Village, Nanjian Yi Autonomous County and Dongyuan Village, Gucheng District (1 086.10 m), and the largest longitude difference was found between Qiandian Village, Eryuan County and Cangling Village, Chuxiong County (1.86°), while the largest latitude difference was measured between Leqiu Village, Nanjian Yi Autonomous County and Dongyuan Village, Gucheng District (1.81°). In addition, the mitochondrial genetic distance of O. hupensis robertsoni snail populations was positively correlated with altitude at 13 snail sampling sites in Yunnan Province (r = 0.542 8, P < 0.001), and showed no significant correlations with geographical distance (r = 0.093 4, P > 0.05), longitude (r = −0.199 5, P > 0.05) or latitude (r = 0.205 7, P > 0.05). Conclusion Altitude may be a potential spatial factor affecting the genetic differentiation of O. hupensis robertsoni in Yunnan Province.

Objective To investigate the distribution characteristics of Oncomelania hupensis snails in Yunnan Province fol-lowing interruption of schistosomiasis transmission, so as to provide the evidence for assessing the risk of schistosomiasis transmission and scientifically formulating the schistosomiasis surveillance program. Methods According to the requirements of the National Schistosomiasis Surveillance Scheme (2020 Edition), O. hupensis snail surveillance data were collected from 18 schistosomiasis-endemic counties (cities, districts) in Yunnan Province from 2020 to 2024, including area of snail survey, area of snail habitats, area of re-emerging snail habitats, number of frames surveyed, number of frames with O. hupensis snails, number of O. hupensis snails captured, and number of living snails, and the occurrence of frames with snails and mean density of living snails were calculated. Changes in snail status over the 5-year period from 2020 to 2024 and the differences in snail distributions specified by epidemic intensity, environmental type, and vegetation type were analyzed. Results The areas of snail survey increased from 1 727.96 hm² in 2020 to 3 894.45 hm² in 2024 (peak) across 18 schistosomiasis-endemic counties (cities, districts) in Yunnan Province during the period from 2020 through 2024. The areas of snail habitats increased from 70.36 hm² in 2020 to a peak in 2023 (172.04 hm²), followed by a reduction to 132.36 hm² in 2024, and the areas of re-emerging snail habitats increased from 42.71 hm² in 2020 to a peak in 2022 (78.43 hm²), followed by a reduction to 40.21 hm² in 2024. The occurrence of frames with snails and mean density of living snails increased from 1.24% (3 025/244 404) and (0.033 2 ± 0.038 7) snails/0.1 m² in 2020 to peaks at 2.03% (6 231/307 563) and (0.066 9 ± 0.068 4) snails/0.1 m² in 2023, followed by reductions to 1.04% (5 829/559 941) and (0.032 6 ± 0.057 7) snails/0.1 m² in 2024, respectively. There was a significant difference in the occurrence of frames with snails over the 5-year study period (χ² = 1 962.95, P < 0.05), and the occurrence of frames with snails reduced by 48.71% in 2024 relative to in 2023 (χ² = 1 411.05, P < 0.005); however, there was no significant difference in the mean density of living snails over the 5 years (H = 5.310, P > 0.05). There were significant differences in the occurrence of frames with snails (χ² = 481.27, P < 0.05) and mean density of living snails (H = 6.872, P < 0.05) in schistosomiasis-endemic areas with different epidemic intensities. The occurrence of frames with snails (χ² = 25.32 and 38.70, both P values < 0.017) and mean density of living snails (Z = 28.55 and 49.96, both P values < 0.017) were higher in schistosomiasis transmission-interrupted and eliminated areas with snails than in schistosomiasis-eliminated areas without snails, and the occurrence of frames with snails (χ² = 453.54, P < 0.017) and mean density of living snails (Z = −56.97, P < 0.017) were higher in schistosomiasis-eliminated areas with snails than in schistosomiasis transmission-interrupted areas with snails. O. hupensis snails were mainly distributed in paddy fields, dry farmlands and ditches; however, the occurrence of frames with snails (13.40%, 424/3 164) and mean density of living snails [(0.252 8 ± 0.158 7) snails/0.1 m²] were higher in ponds/weirs than in other types of environments (both P values < 0.05). Rice, dry farmland crops and weeds were main vegetations in which O. hupensis snails were distributed, and the occurrence of frames with snails (2.29%, 7 111/310 140) and mean density of living snails [(0.072 3 ± 0.018 9) snails/0.1 m²] were higher in weeds than in other types of environments (both P values < 0.05). Conclusions O. hupensis snails have been effectively controlled in Yunnan Province following implementation of integrated schistosomiasis control measures; however, there are still risk factors for schistosomiasis transmission, including reduced attention to schistosomiasis control and snail re-emergence. Improved control efforts and surveillance system construction and timely identification of risk factors of snail status and timely management are recommended to ensure the achievement of the target of schistosomiasis elimination as scheduled.

Nicotinic acetylcholine receptors (nAChRs) are pentameric ligand-gated ion channels (pLGICs) that mediate rapid cholinergic synaptic transmission throughout the central and peripheral nervous systems. These receptors are integral to neuromuscular junction signaling, autonomic regulation, cognitive learning, reward-related behavior, and neuroplasticity. The nAChR family exhibits remarkable functional diversity through combinatorial assembly of seventeen identified subunits (α1-α10, β1-β4, γ, δ, and ε). Among these, the α9 subunit occupies a distinctive phylogenetic position, exhibiting greater sequence divergence from other neuronal α subunits and possessing unique biochemical properties that distinguish it from all other family members. α9 can form homopentamers and also co-assemble with the α10 subunit to form functional heteropentamers, primarily in (α9)₂(α10)₃ and (α9)₃(α10)₂ stoichiometries. This dual assembly strategy generates functional heterogeneity, as distinct subunit compositions confer differential ion permeation, ligand sensitivity, and desensitization kinetics. The structural determinants governing this stoichiometric variability remain incompletely resolved, representing a critical gap in our mechanistic understanding. Unlike most other nAChR subtypes, traditional agonists of nAChRs (such as nicotine) elicit virtually no agonistic effect on α9* nAChRs (α9-containing receptors, including α9 homopentamers and α9α10 heteropentamers). This pharmacological divergence reflects structural differences within the orthosteric site, particularly in regions at complementary subunit interfaces. As cation-selective channels, α9* nAChRs exhibit high permeability to Ca²⁺. In cochlear outer hair cells, α9α10 nAChRs mediate cholinergic efferent modulation by the medial olivocochlear (MOC) bundle. Acetylcholine-evoked Ca²⁺ influx activates functionally coupled SK2 potassium channels, generating net hyperpolarization that dampens electromechanical amplification through a tightly constrained signaling microdomain. This Ca²⁺-dependent excitatory-to-inhibitory conversion exemplifies sophisticated sensory gain control, and its disruption contributes to noise-induced hearing loss, age-related hearing loss, and tinnitus. Beyond canonical ionotropic signaling, α9* nAChR engages metabotropic transduction pathways. In macrophages, receptor activation modulates cytokine production and inflammatory responses. In keratinocytes, it regulates wound healing by modulating cell migration and differentiation. In dorsal root ganglion sensory neurons, α9* signaling contributes to nociceptive processing and inflammatory hyperalgesia. This functional pleiotropy, spanning both ionotropic signaling and metabotropic transduction, positions α9* nAChR as an exemplary model for investigating signal polymorphism within the pLGIC superfamily. Pathophysiologically, α9* nAChR dysfunction is implicated across multiple organ systems. In the auditory system, disruption of α9α10 nAChR-mediated MOC efferent feedback impairs cochlear gain control, predisposing to noise-induced synaptopathy and age-related hearing loss. In immune cells, dysfunctional α9* nAChR signaling disrupts cholinergic anti-inflammatory pathway activity, exacerbating pro-inflammatory responses. In the peripheral sensory system, aberrant α9* nAChR signaling has been implicated in neuropathic and inflammatory pain states. In skin, impaired receptor function compromises keratinocyte migration and re-epithelialization through disrupted signaling pathways, leading to chronic wound healing defects and inflammation. These pathophysiological associations have catalyzed pharmacological interest, yielding promising chemical entities including α‑conotoxins, small-molecule antagonists/agonists, and allosteric modulators.α-Conotoxin peptides, in particular, demonstrate remarkable subunit selectivity and potent antinociceptive effects in preclinical pain models. However, therapeutic translation faces substantial challenges: the broad tissue distribution of α9* nAChR risks on-target adverse effects in non-target organs; pronounced species differences between rodent and human receptors complicate preclinical validation; and the complexity of ionotropic-metabotropic signaling crosstalk demands pharmacological strategies that extend beyond conventional orthosteric agonism or antagonism. Looking forward, integrating cryo-electron microscopy of full-length receptors in distinct conformational states with single-channel electrophysiology and systems-level circuit analysis promises to illuminate the molecular mechanisms governing α9* nAChR function and regulation. The development of signal pathway-biased ligands and tissue-selective delivery strategies may ultimately harness the therapeutic potential of this receptor while mitigating safety liabilities. As a paradigm for understanding pLGIC signaling diversification, α9* nAChR research will continue to inform broader questions regarding ion channel evolution, allosteric regulation, and pathophysiological mechanisms of chronic pain and autoimmune inflammatory diseases.

ObjectiveTo explore the potential mechanism of acupuncture with the method of soothing the liver and regulating the mind in improving depressive disorder. MethodsEighteen C57BL/6J mice were randomly divided into blank group， model group， and acupuncture group， with 6 mice in each group. The model group and the acupuncture group were subjected to depression induction by intraperitoneal injection of lipopolysaccharide （LPS）， while the blank group received an equal volume of normal saline once daily for seven consecutive days. Concurrently， the acupuncture group received "soothing the liver and regulating the mind" acupuncture intervention starting from the first day of modeling， once daily for 14 days； whereas the blank group and the model group were only restrained without acupuncture. The sucrose preference test was used to assess sucrose preference rate， the open-field test to measure center stay time and total travel distance， and the forced swim test to evaluate immobility time. Hematoxylin-eosin （HE） staining was performed to observe hippocampal morphological changes. Enzyme-linked immunosorbent assay （ELISA） was used to detect levels of interleukin-1β （IL-1β）， interleukin-6 （IL-6）， and tumor necrosis factor-α （TNF-α） in hippocampal tissue. Western blot analysis was conducted to examine the protein expression levels of Toll-like receptor 4 （TLR4） and nuclear factor-κB （NF-κB） in the hippocampus. ResultsCompared to the blank group， the model group showed a significant reduction in sucrose preference rate， center stay time， and total travel distance， along with a significant increase in immobility time in the forced swim test， hippocampal IL-1β， IL-6， and TNF-α levels， as well as TLR4 and NF-κB protein expression （P＜0.01）， and the histological examination revealed blurred hippocampal neuronal boundaries， loose arrangement， and some neurons exhibiting nuclear pyknosis and deep staining. Compared to the model group， the acupuncture group demonstrated a significant increase in sucrose preference rate， center stay time， and total travel distance， along with a significant reduction in immobility time in the forced swim test， hippocampal IL-1β， IL-6， and TNF-α levels， and TLR4 and NF-κB protein expression （P＜0.01）， and the histological analysis showed that hippocampal neurons in the acupuncture group were more tightly arranged， with reduced nuclear pyknosis and deep staining. ConclusionAcupuncture with the "soothing the liver and regulating the mind" method can significantly improve depression-like behavior， potentially by inhibiting the hippocampal TLR4/NF-κB signaling pathway and alleviating inflammatory responses.

Objective:To investigate the drug resistance of newly diagnosed HIV-1 infected patients in Shanghai and to provide reference value for clinical antiretroviral therapy (ART).Methods:The peripheral venous blood plasma of 196 newly diagnosed HIV-1 infected patients screened according to the inclusion and exclusion criteria at the Shanghai Public Health Clinical Center from April to June 2023 was collected, HIV-1 RNA was extracted, the pol region was amplified by reverse transcription-polymerase chain reaction (RT-PCR) for sequencing, the mutation sites and ART drug resistance were analyzed.Results:The plasma of 196 newly diagnosed HIV-1 infected patients was amplified successfully in 162 cases (amplification success rate was 82.65%). The subtypes consisted of CRF07_BC(51.23%), CRF01_AE (27.78%), and others (6.79%), CRF55_01B (5.56%), B (3.70%), CRF01_AE/B (3.70%) and CRF08_BC (1.23%). The overall transmitted drug resistance rate was 7.41%, the protease inhibitors (PIs), non-nucleoside/nucleotide reverse transcriptase inhibitors (NNRTIs), nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs), integrase inhibitors (INSTIs) resistance rates were 3.09%, 3.70%, 0.00% and 0.62%, respectively. The proportion of NNRTIs-related mutation sites in B (66.67%) and CRF55_01B (88.89%) was higher than that in CRF07_BC (13.25%); the proportion of NNRTIs-related mutation sites in CRF55_01B (88.89%) was higher than that in CRF01_AE (22.22%) and other subtypes (18.18%), the difference was statistically significant (all P<0.05). Multivariate logistic regression analysis showed that the probability of PIs-related mutation sites in CRF01_AE/B was 21.71 times that of CRF07_BC[odds ratio ( OR)=21.71, 95% confidence interval ( CI): 3.36-140.27, P=0.001]. Conclusions:The transmitted drug resistance among newly diagnosed HIV-1 infected patients in Shanghai is at the moderate epidemic level, mainly NNRTIs and PIs-related drug resistance, and the INSTIs resistance rate is low, the use of INSTIs in ART regimens should be considered.

Aim To investigate the role of miR-130b-3p in regulating the USP47/NLRP3 inflammasome in airway remodeling associated with asthma and to explore its potential therapeutic value in asthma treat-ment.Methods An OVA-induced asthma mouse mod-el was established,and intervention with miR-130b-3p agomir was performed.Histological staining,quantita-tive real-time PCR,Western blot,immunofluorescence and flow cytometry were used to analyze the effects of miR-130b-3p on the expression of USP47,NLRP3,and related inflammatory factors,as well as the inflamma-some activity.Results miR-130b-3p was significantly downregulated in asthmatic mice,and its intervention significantly inhibited airway epithelial damage,inflam-matory cell infiltration,and collagen deposition.Addi-tionally,miR-130b-3p targeted USP47 and indirectly suppressed NLRP3 expression,leading to reduced in-flammasome activity and alleviated asthma-related in-flammatory responses.Conclusion miR-130b-3p re-duces asthma-related inflammatory responses by down-regulating USP47 expression and indirectly inhibiting NLRP3 inflammasome activity.

Icaritin(ICT)is an 8-isopentenylflavonoid,which is the main effective component of the tra-ditional Chinese medicine Epimedium.Previously,we found that Icaritin inhibits the growth of glioblasto-ma(GBM)cells.Herein we aim to study the in vivo anti-GBM effectiveness of Icaritin and explore its mechanism.The results of MTT assay,flow cytometry,comet assay and cellular immunofluorescence as-say in vitro showed that ICT inhibited the proliferation of four kinds of GBM cells,U87,U251,U118 and A172,induced early apoptosis(P＜0.001)and late apoptosis(P＜0.05)in U87 cells,induced DNA damage in U87 cells,and blocked the growth of U87 cells at the G0/G1 phase(P＜0.0001)in a concen-tration-time-dependent manner.In vivo subcutaneous tumor transplantation tumor experiments showed that feeding 200 mg/kg(P＜0.01)and 400 mg/kg(P＜0.001)ICT had a significant inhibitory effect on the growth of GBM subcutaneous tumors,and had no significant toxic effects on heart,liver,spleen,lung and kidney tissues.The results of network pharmacological analysis,molecular docking and cellular thermodynamic experiments showed that there were 26 possible target proteins between ICT and GBM,a-mong which the expression of p53 in GBM tissues was significantly(P＜0.001)higher than in normal tis-sues,and the binding energy of ICT and p53 was lower;cellular thermodynamic experiments verified that ICT significantly enriched the level of p53 in the living cells of GBM,which indicated that ICT could tar-get p53.The expression of key proteins in the DNA damage repair and apoptosis-associated FOXO signa-ling pathway was detected by ICT.The results showed that the expression of ATR(P＜0.01),P53(P＜0.001),P21(P＜0.05)and γ-H2AX(P＜0.05)was up-regulated,whereas the expression of Cyc-lin E1(P＜0.01),E2F1(P＜0.05),CDK2(P＜0.01),Rb(P＜0.001),p-Rb(P＜0.0001)and WRN(P＜0.0001)expression were down-regulated.There was no significant change in the expres-sion of FOXO 1 in the FOXO pathway or a significant down-regulation of its phosphorylation level.This study demonstrated that ICT could effectively inhibit the growth of GBM cells in vivo.It targets p53 to regulate the DNA damage repair pathway and FOXO signaling pathway to induce GBM cell cycle arrest and apoptosis.

AIM To investigate the protective effects of Shuangyi Qushi Tongluo Capsules(Shuangyi Capsules)on Dexamethasone(Dex)induced osteoporosis in mice.METHODS The C57BL/6J mice were randomly divided into the control group,the model group,the Xianling Gubao Capsules group(1.5 g/kg),and the low-dose,moderate-dose,and high-dose Shuangyi Capsules groups(0.6,1.2,and 2.4 g/kg).The mouse model of osteoporosis was induced by 8-week intraperitoneal injection of Dex sodium phosphate injection(5 mg/kg).The mice had their femur osteogenesis observed with hematoxylin and eosin(HE)staining and tartrate-resistant acid phosphatase(TRAP)staining;their serum alkaline phosphatase(ALP)and osteocalcin(BGP)activities detected by ELISA;their femoral mRNA expressions of Col-Ⅰ,OCN,and OPN detected by RT-qPCR;and their femoral protein expressions of OPG and RANKL detected by Western blot.Upon the MC3T3-E1 cells exposed to Dex and Shuangyi Capsules,their viability was evaluated by CCK-8 assay;their mineralization determined by alkaline phosphatase staining and alizarin red staining(ARS);and their intracellular ROS level detected using DCFH-DA probe.RESULTS Compared with the model group,Shuangyi Capsules groups demonstrated improved fracture of femoral trabeculae and reduced number of osteoclasts;increased serum ALP and BGP activities(P＜0.05,P＜0.01);increased femoral expressions of Col-Ⅰ mRNA and OPG protein(P＜0.05,P＜0.01);and decreased RANKL protein expression(P＜0.05).Compared with the MC3T3-E1 cells stimulated by Dex,those underwent further treatment of Shuangyi Capsules demonstrated increased cell viability and ALP activity(P＜0.05,P＜0.01);increased mineralization and calcium nodule formation;increased expressions of Col-Ⅰ,OCN,OPN mRNA and OPG protein(P＜0.05,P＜0.01);decreased RANKL protein expression(P＜0.05,P＜0.01);and reduced ROS levels.CONCLUSION Shuangyi Capsules ameliorate Dex-induced osteoporosis in mice by suppressing osteoclast overactivation,enhancing osteoblast activity,and stimulating bone formation through modulation of Col-Ⅰ,OCN,OPN mRNA and OPG/RANKL protein levels.

Objective:To evaluate the efficacy and safety of blinatumomab in adult patients with relapsed/refractory(R/R)or measurable residual disease(MRD)positive B-cell acute lymphoblastic leukemia(B-ALL)in the real world.Methods:The clinical data of 30 B-ALL patients received at least 1 course of blinatumomab therapy in the Chinese PLA General Hospital from January 1st,2021 to December 31st,2023 were retrospectively analyzed,including pre-treatment baseline clinical feature,post-treatment complete response(CR),CR with partial hematologic recovery(CRh),CR with incomplete hematologic recovery(CRi),complete MRD response rate,MRD response rate(MRD＜10-4),overall survival(OS),and disease-free survival(DFS),as well as drug-related adverse reactions.Results:Among 5 patients who were not assessed 4 were MRD negative and 1 did not receive bone marrow biopsy.In the R/R B-ALL group(13 cases),11 patients achieved CR/CRh/CRi and 10 patients achieved complete MRD response.In MRD+group(12 cases),9 patients achieved overall MRD response and 7 patients achieved complete MRD response.The median follow-up time was 8.4(95％CI:6.3-10.4)months.The median OS was 15.5(95％CI:0.7-30.3)months in the R/R group,while not reached in the MRD+group.The median DFS of the two groups were not reached.Drug-related adverse reactions occurred in 22 patients,and pyrexia was the most common(13 cases).Grade ≥3 adverse reactions occurred in 15 patients,and neutropenia was the most common(9 cases).Cytokine release syndrome occurred in 6 patients,including 5 cases with grade 1 and 1 case with grade 3.No patients interrupted therapy or died due to drug-related adverse reactions.Conclusion:Blinatumomab is effective in the treatment of R/R or continuous MRD+B-ALL with acceptable adverse reactions.

This study analyzed soil-transmitted nematode infection surveillance data for children 3-9 years of age in Shaanxi Province from 2016 to 2023,to provide a scientific basis for control strategies for soil-transmitted nematode infections in children in the province.Since 2016,according to the requirements of the National Schistosomiasis and Soil-transmitted Nematode Surveillance Program(Trial),several counties and districts in Shaanxi Province were selected as surveillance sites every year.According to geo-graphical position,the surveillance sites were divided into five areas:east,west,south,north and middle,and one administrative vil-lage(community)was selected in each area for monitoring.The eggs of soil-transmitted nematodes(hookworm,Ascaris lumbricoides,Trichuris trichiura,and Enterobius vermicularis)were detected with the Kato-Katz technique in children 3-9 years of age at each sur-veillance site,and the eggs of Enterobius vermicularis were detected again with the cellophane tape anal swab method.The infection rate and intensity for E.vermicularis were calculated.Detection was performed in 12 462 children 3-9 years old at 75 surveillance sites in Shaanxi Province from 2016 to 2023;84 cases of soil-borne nematode infections were detected,and the overall infection rate was 0.67%.The infection rates for Ascaris lumbricoides and E.vermicularis were 0.18%(22/12 462)and 0.50%(62/12 462),respec-tively,and the infection rates for Trichuris trichiura and hookworm were not found.The infection rates of soil-transmitted nematodes in children were 1.28%(16/1 250),0.16%(2/1 252),1.25%(17/1 365),1.20%(18/1 494),0.17%(2/1 169),1.45%(20/1 382),0.00,and 0.36%(9/251),respectively.A linear trend was observed among years(χ2=11.973,P<0.001).The infection rates in the Weifen Basin ecological region,Loess Plateau ecological region,and Qinba Mountains ecological region were 0.51%,1.19%,and 0.72%,respectively,and the differences were statistically significant(χ2=9.726,P=0.008).Significant differences in infection rates were observed among scattered children(1.63%),preschool children(0.66%),and students(0.57%)(χ2=11.189,P=0.004).No significant differences in infection rates were observed by gender,age,and education level.Compared with the infection rates in the entire country and other provinces,the infection rate of soil-transmitted nematodes among children in Shaanxi Province was low,and the main infection species were Ascaris lumbricoides and E.vermicularis.The infection rates greatly varied within Shaanxi Prov-ince,possibly because of differences in economic development levels,children′s living habits,and personal hygiene status across re-gions.In the future,comprehensive control measures should be taken to strengthen the monitoring and control of key areas,popula-tions,and parasite species.