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Stephenson JF, Perkins SE, Cable J. Transmission risk predicts avoidance of infected conspecifics in Trinidadian guppies. J Anim Ecol 2018; 87:1525-1533. [PMID: 30047991 DOI: 10.1111/1365-2656.12885] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 07/14/2018] [Indexed: 01/23/2023]
Abstract
Associating with conspecifics afflicted with infectious diseases increases the risk of becoming infected, but engaging in avoidance behaviour incurs the cost of lost social benefits. Across systems, infected individuals vary in the transmission risk they pose, so natural selection should favour risk-sensitive avoidance behaviour that optimally balances the costs and benefits of sociality. Here, we use the guppy Poecilia reticulata-Gyrodactylus turnbulli host-parasite system to test the prediction that individuals avoid infected conspecifics in proportion to the transmission risk they pose. In dichotomous choice tests, uninfected fish avoided both the chemical and visual cues, presented separately, of infected conspecifics only in the later stages of infection. A transmission experiment indicated that this avoidance behaviour accurately tracked transmission risk (quantified as both the speed at which transmission occurs and the number of parasites transmitting) through the course of infection. Together, these findings reveal that uninfected hosts can use redundant cues across sensory systems to inform dynamic risk-sensitive avoidance behaviour. This correlation between the transmission risk posed by infected individuals and the avoidance response they elicit has implications for the evolutionary ecology of infectious disease, and its explicit inclusion may improve the ability of epidemic models to predict disease spread.
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Affiliation(s)
- Jessica F Stephenson
- Center for Adaptation to a Changing Environment, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland.,Department of Aquatic Ecology, EAWAG, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland.,School of Biosciences, Cardiff University, Cardiff, UK
| | | | - Joanne Cable
- School of Biosciences, Cardiff University, Cardiff, UK
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Ji L, Yiyue X, Xujin H, Minghui Z, Mengying Z, Yue H, Yanqi W, Langui S, Xin Z, Datao L, Shuo W, Huanqin Z, Zhongdao W, Zhiyue L. Study on the tolerance and adaptation of rats to Angiostrongylus cantonensis infection. Parasitol Res 2017; 116:1937-1945. [PMID: 28493001 DOI: 10.1007/s00436-017-5472-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Accepted: 05/02/2017] [Indexed: 01/14/2023]
Abstract
Angiostrongylus cantonensis (A. cantonensis) is the most common infectious agent causing eosinophilic meningitis. As an important food-borne parasitic disease, angiostrongyliasis cantonensis is an emerging infectious disease which brings severe harm to central nerve system of human. Rat, one of the few permissive hosts of A. cantonensis known to date, plays an indispensable role in the worm's life cycle. However, the tolerance and adaptation of rat to A. cantonensis infection is rarely understood. In this study, we infected rats with different numbers the third stage larvae (L3) of A. cantonensis and explored their tolerance through analysis on survival curve, neurological function score, and detection of pathological damages in organs including the brain, lung, and heart of the animals. Results indicated that rats' survival condition worsens, and body weight dropped more significantly as more worms were used for infection. Death appeared in groups infected with 80 and more A. cantonesnsis per rat. Morris water maze revealed that the neurological function of rats damaged gradually with increasing infection number of A. cantonensis larvae. When the number of infected parasite exceeded 240 per animal, rats showed significant neurological impairments. Collection of A. cantonensis from rat lung after 35 days of infection implied an upper limit for worm entry, and the average length of worm was inversely proportional to the infection amount, while the ratio between female and male worms was positively related to the infection number. The degree of pulmonary and cardiac inflammation was proportional to the infection number of A. cantonensis. Meanwhile, there existed considerable amount of adult worms in rat's right atrium and right ventricle, leading to a right heart myocardial inflammation. The present study firstly reports the tolerance and adaptation of rat, a permissive host of A. cantonensis to its infection, which will not only provide accurate technical parameters for maintaining A. cantonensis life cycle under laboratory conditions but also help unveil the underlying mechanism of the distinct pathological outcomes in the permissive and non-permissive hosts with A. cantonensis infection.
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Affiliation(s)
- Liu Ji
- Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou, 510080, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou, 510080, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, 510080, China
| | - Xu Yiyue
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, SAR, China.,State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, SAR, China
| | - He Xujin
- The Affiliated High School of South China Normal University, Guangzhou, 510630, China
| | - Zheng Minghui
- Department of Clinical Laboratory, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, 510120, China
| | - Zhang Mengying
- Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou, 510080, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou, 510080, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, 510080, China
| | - Hu Yue
- Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou, 510080, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou, 510080, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, 510080, China
| | - Wu Yanqi
- Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou, 510080, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou, 510080, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, 510080, China
| | - Song Langui
- Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou, 510080, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou, 510080, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, 510080, China
| | - Zeng Xin
- Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou, 510080, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou, 510080, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, 510080, China
| | - Lin Datao
- Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou, 510080, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou, 510080, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, 510080, China
| | - Wan Shuo
- Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou, 510080, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou, 510080, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, 510080, China
| | - Zheng Huanqin
- Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou, 510080, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou, 510080, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, 510080, China
| | - Wu Zhongdao
- Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou, 510080, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou, 510080, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, 510080, China
| | - Lv Zhiyue
- Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou, 510080, China. .,Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou, 510080, China. .,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, 510080, China.
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Stephenson JF, Young KA, Fox J, Jokela J, Cable J, Perkins SE. Host heterogeneity affects both parasite transmission to and fitness on subsequent hosts. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160093. [PMID: 28289260 PMCID: PMC5352819 DOI: 10.1098/rstb.2016.0093] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/15/2016] [Indexed: 12/16/2022] Open
Abstract
Infectious disease dynamics depend on the speed, number and fitness of parasites transmitting from infected hosts ('donors') to parasite-naive 'recipients'. Donor heterogeneity likely affects these three parameters, and may arise from variation between donors in traits including: (i) infection load, (ii) resistance, (iii) stage of infection, and (iv) previous experience of transmission. We used the Trinidadian guppy, Poecilia reticulata, and a directly transmitted monogenean ectoparasite, Gyrodactylus turnbulli, to experimentally explore how these sources of donor heterogeneity affect the three transmission parameters. We exposed parasite-naive recipients to donors (infected with a single parasite strain) differing in their infection traits, and found that donor infection traits had diverse and sometimes interactive effects on transmission. First, although transmission speed increased with donor infection load, the relationship was nonlinear. Second, while the number of parasites transmitted generally increased with donor infection load, more resistant donors transmitted more parasites, as did those with previous transmission experience. Finally, parasites transmitting from experienced donors exhibited lower population growth rates on recipients than those from inexperienced donors. Stage of infection had little effect on transmission parameters. These results suggest that a more holistic consideration of within-host processes will improve our understanding of between-host transmission and hence disease dynamics.This article is part of the themed issue 'Opening the black box: re-examining the ecology and evolution of parasite transmission'.
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Affiliation(s)
- Jessica F Stephenson
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
- Department of Aquatic Ecology, EAWAG, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Center for Adaptation to a Changing Environment, ETH Zürich, 8092 Zürich, Switzerland
| | - Kyle A Young
- Institute of Evolutionary Biology and Environmental Studies, University of Zürich, 8057 Zürich, Switzerland
| | - Jordan Fox
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - Jukka Jokela
- Department of Aquatic Ecology, EAWAG, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute of Integrative Biology, ETH Zürich, 8092 Zürich, Switzerland
| | - Joanne Cable
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - Sarah E Perkins
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
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