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Wang X, Shang M, Wang Z, Ji H, Wang Z, Mo G, Liu Q. Effects of individual characteristics and seasonality and their interaction on ectoparasite load of Daurian ground squirrels in Inner Mongolia, China. Int J Parasitol Parasites Wildl 2024; 25:101014. [PMID: 39558943 PMCID: PMC11570501 DOI: 10.1016/j.ijppaw.2024.101014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2024] [Revised: 10/29/2024] [Accepted: 10/29/2024] [Indexed: 11/20/2024]
Abstract
Understanding the drivers of parasite distribution is vital for ecosystem health, disease management, and vector monitoring. While studies note the impact of host sex, size, behavior, and season on parasite load, concurrent assessments of these factors and their interactions are limited. During the spring, summer and autumn seasons from 2021 to 2023, we trapped Daurian ground squirrel (Spermophilus dauricus), a small rodent species that inhabits eastern Asian grasslands in Inner Mongolia and collected their ectoparasites. Using machine learning Lasso regression, we pinpointed factors affecting tick and flea abundance on S. dauricus. We then analyzed these factors and their seasonal interactions with a mixed negative binomial generalized linear model. Our study revealed significant but inconsistent seasonal effects on the load of ectoparasites. The tick load was significantly higher in spring and summer compared to autumn, while the flea load was higher in summer and autumn but lacked statistical significance. Furthermore, individual factors that influence the flea and tick load were moderated by seasonal effects, with a male bias in flea parasitism observed in spring. Significant interactions were also found among seasonality, sex, and body weight. The load of male squirrel fleas was positively correlated with body weight, with the highest increase observed in spring. On the contrary, the flea load of female squirrels showed a negative correlation with body weight, significantly decreasing in the autumn with increasing weight. Significant interactions were observed between season and survival status, with hosts exhibiting higher tick load during autumn survival. Our findings underscore the importance of considering seasonal variation in parasitism and the interactions between seasonal dynamics and host biological traits in shaping parasite distributions.
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Affiliation(s)
- Xiaoxu Wang
- Department of Vector Control, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, 250012, China
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Disease, Department of Vector Biology and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China
| | - Meng Shang
- Department of Vector Control, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, 250012, China
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Disease, Department of Vector Biology and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China
| | - Zihao Wang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Disease, Department of Vector Biology and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China
- School of Public Health, Nanjing Medical University, Nanjing, 211112, China
| | - Haoqiang Ji
- Department of Vector Control, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, 250012, China
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Disease, Department of Vector Biology and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China
| | - Zhenxu Wang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Disease, Department of Vector Biology and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China
| | - Guangju Mo
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Disease, Department of Vector Biology and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China
- School of Public Health, Weifang Medical College, 261053, China
| | - Qiyong Liu
- Department of Vector Control, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, 250012, China
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Disease, Department of Vector Biology and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China
- School of Public Health, Nanjing Medical University, Nanjing, 211112, China
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Kuo CC, Huang JL, Wang HC. Parasite infestation patterns differ between ticks and chigger mites on two rodent host species in Taiwan. EXPERIMENTAL & APPLIED ACAROLOGY 2024; 93:35-48. [PMID: 38695989 DOI: 10.1007/s10493-024-00918-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Accepted: 04/16/2024] [Indexed: 06/18/2024]
Abstract
Parasites are typically concentrated on a few host individuals, and identifying the mechanisms underlying aggregated distribution can facilitate a more targeted control of parasites. We investigated the infestation patterns of hard ticks and chigger mites on two rodent species, the striped field mouse, Apodemus agrarius, and the lesser ricefield rat, Rattus losea, in Taiwan. We also explored abiotic and biotic factors that were important in explaining variation in the abundance of ticks and chiggers on rodent hosts. Ticks were more aggregated than chiggers on both rodent species. Factors important for the variation in parasitic loads, especially biotic factors, largely differed between ticks and chiggers. Variation partitioning analyses revealed that a larger proportion of variation in chiggers than in ticks can be explained, especially by abiotic factors. If, as proposed, the higher number of parasites in males is due to a larger range area or immunity being suppressed by testosterone, when A. agrarius males host more ticks, they are expected to also host more chiggers, given that chiggers adopt a similar host finding approach to that of ticks. Instead, the similar abundance of chiggers in male and female A. agrarius implies that a large home range or suppressed immunity does not predispose males to inevitably host more parasites. More variations were explained by abiotic than biotic factors, suggesting that controlling practices are more likely to be successful by focusing on factors related to the environment instead of host traits. Our study indicated that the extent of parasitism is rarely determined by a sole factor, but is an outcome of complex interactions among animal physiology, animal behavior, characteristics of parasites, and the environments.
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Affiliation(s)
- Chi-Chien Kuo
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan.
- Department of Wildlife, Fish, and Conservation Biology, University of California, One Shields Avenue, 95616, Davis, CA, USA.
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taipei, Taiwan.
| | - Jing-Lun Huang
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taipei, Taiwan
- Biodiversity Research Center, National Taiwan University, Taipei, Taiwan
| | - Hsi-Chieh Wang
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taipei, Taiwan.
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Lindsø LK, Viljugrein H, Mysterud A. Vector competence of Ixodes ricinus instars for the transmission of Borrelia burgdorferi sensu lato in different small mammalian hosts. Parasit Vectors 2024; 17:23. [PMID: 38238796 PMCID: PMC10797980 DOI: 10.1186/s13071-023-06110-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 12/22/2023] [Indexed: 01/22/2024] Open
Abstract
BACKGROUND Many pathogens and parasites can infect multiple host species, and the competence of different hosts as pathogen reservoirs is key to understanding their epidemiology. Small mammals are important hosts for the instar stages of Ixodes ricinus ticks, the principal vector of Lyme disease in Europe. Small mammals also act as reservoirs of Borrelia afzelii, the most common genospecies of the Borrelia burgdorferi sensu lato (s.l.) spirochetes causing Lyme disease in Europe. However, we lack quantitative estimates on whether different small mammal species are equally suitable hosts for feeding I. ricinus and whether they show differences in pathogen transmission from host to tick. METHODS Here, we analysed the feeding success and prevalence of B. burgdorferi s.l. infections in 12,987 instar I. ricinus found on captured small mammals with known infection status in Norway (2018-2022). RESULTS We found that larvae were more likely to acquire a blood meal from common shrews (Sorex araneus, 46%) compared to bank voles (Myodes glareolus, 36%) and wood mice (Apodemus sylvaticus, 31%). Nymphs tended to be more likely to acquire a blood meal from wood mice (66%) compared to bank voles (54%). Common shrews harboured few nymphs (n=19). Furthermore, we found that larvae feeding on infected bank voles (11%) were more likely to be infected with B. burgdorferi s.l. than larvae on infected common shrews (7%) or wood mice (4%). CONCLUSIONS Our study provides quantitative evidence of differences in suitability for the instar stages of I. ricinus across taxa of small mammals and highlights how even known small mammal host species can differ in their ability to feed ticks and infect larval ticks with the pathogen causing Lyme disease.
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Affiliation(s)
- Lars K Lindsø
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Blindern, P.O. Box 1066, NO-0316, Oslo, Norway.
| | - Hildegunn Viljugrein
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Blindern, P.O. Box 1066, NO-0316, Oslo, Norway
- Norwegian Veterinary Institute, P.O. Box 64, NO-1431, Ås, Norway
| | - Atle Mysterud
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Blindern, P.O. Box 1066, NO-0316, Oslo, Norway
- Norwegian Institute for Nature Research (NINA), Torgarden, P.O. Box 5685, NO-7485, Trondheim, Norway
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