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Kjær LJ, Johansson M, Lindgren PE, Asghar N, Wilhelmsson P, Fredlund H, Christensson M, Wallenhammar A, Bødker R, Rasmussen G, Kjellander P. Potential drivers of human tick-borne encephalitis in the Örebro region of Sweden, 2010-2021. Sci Rep 2023; 13:7685. [PMID: 37169798 PMCID: PMC10175290 DOI: 10.1038/s41598-023-34675-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 05/05/2023] [Indexed: 05/13/2023] Open
Abstract
Incidence of tick-borne encephalitis (TBE) has increased during the last years in Scandinavia, but the underlying mechanism is not understood. TBE human case data reported between 2010 and 2021 were aggregated into postal codes within Örebro County, south-central Sweden, along with tick abundance and environmental data to analyse spatial patterns and identify drivers of TBE. We identified a substantial and continuing increase of TBE incidence in Örebro County during the study period. Spatial cluster analyses showed significant hotspots (higher number of cases than expected) in the southern and northern parts of Örebro County, whereas a cold spot (lower number of cases than expected) was found in the central part comprising Örebro municipality. Generalised linear models showed that the risk of acquiring TBE increased by 12.5% and 72.3% for every percent increase in relative humidity and proportion of wetland forest, respectively, whereas the risk decreased by 52.8% for every degree Celsius increase in annual temperature range. However, models had relatively low goodness of fit (R2 < 0.27). Results suggest that TBE in Örebro County is spatially clustered, however variables used in this study, i.e., climatic variables, forest cover, water, tick abundance, sheep as indicator species, alone do not explain this pattern.
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Affiliation(s)
- Lene Jung Kjær
- Section for Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.
| | - Magnus Johansson
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Per-Eric Lindgren
- Division of Inflammation and Infection, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
- Division of Clinical Microbiology, Department of Laboratory Medicine, Region Jönköping County, Jönköping, Sweden
| | - Naveed Asghar
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Peter Wilhelmsson
- Division of Inflammation and Infection, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
- Division of Clinical Microbiology, Department of Laboratory Medicine, Region Jönköping County, Jönköping, Sweden
| | - Hans Fredlund
- Department of Laboratory Medicine, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
- Örebro County Council, Örebro, Sweden
| | - Madeleine Christensson
- Grimsö Wildlife Research Station, Department of Ecology, Swedish University of Agricultural Sciences (SLU), Riddarhyttan, Sweden
| | - Amélie Wallenhammar
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - René Bødker
- Section for Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Gunløg Rasmussen
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
- Örebro County Council, Örebro, Sweden
| | - Petter Kjellander
- Grimsö Wildlife Research Station, Department of Ecology, Swedish University of Agricultural Sciences (SLU), Riddarhyttan, Sweden
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Kahl O, Gray JS. The biology of Ixodes ricinus with emphasis on its ecology. Ticks Tick Borne Dis 2023; 14:102114. [PMID: 36603231 DOI: 10.1016/j.ttbdis.2022.102114] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 12/20/2022] [Accepted: 12/20/2022] [Indexed: 12/27/2022]
Abstract
Prior to its identification as the vector of Lyme borreliosis spirochaetes in Europe in 1983, interest in Ixodes ricinus (L.) was moderate and mainly concerned the transmission of pathogens to farm animals and of tick-borne encephalitis virus to humans. The situation now is very different, and more papers have been published on I. ricinus than on any other ixodid tick species. However, this large literature is scattered and in recent years has become dominated by the molecular detection and characterization of the many pathogens that I. ricinus transmits. Several decades have now elapsed since a review addressing its basic biology and ecology appeared, and the present publication seeks to present basic aspects of its biology and ecology that are related to its role as a vector of disease agents, including its life cycle, feeding behaviour, host relations, survival off the host, and the impact of weather and climate.
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Affiliation(s)
- Olaf Kahl
- tick-radar GmbH, 10555 Berlin, Germany.
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Aivelo T, Lemoine M, Tschirren B. Elevational Changes in Bacterial Microbiota Structure and Diversity in an Arthropod-Disease Vector. MICROBIAL ECOLOGY 2022; 84:868-878. [PMID: 34599659 PMCID: PMC9622521 DOI: 10.1007/s00248-021-01879-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 09/20/2021] [Indexed: 06/09/2023]
Abstract
Environmental conditions change rapidly along elevational gradients and have been found to affect community composition in macroscopic taxa, with lower diversity typically observed at higher elevations. In contrast, microbial community responses to elevation are still poorly understood. Specifically, the effects of elevation on vector-associated microbiota have not been studied to date, even though the within-vector microbial community is known to influence vector competence for a range of zoonotic pathogens. Here we characterize the structure and diversity of the bacterial microbiota in an important zoonotic disease vector, the sheep tick Ixodes ricinus, along replicated elevational gradient (630-1673 m) in the Swiss Alps. 16S rRNA sequencing of the whole within-tick bacterial microbiota of questing nymphs and adults revealed a decrease in Faith's phylogenetic microbial alpha diversity with increasing elevation, while beta diversity analyses revealed a lower variation in microbial community composition at higher elevations. We also found a higher microbial diversity later in the season and significant differences in microbial diversity among tick life stages and sexes, with lowest microbial alpha diversity observed in adult females. No associations between tick genetic diversity and bacterial diversity were observed. Our study demonstrates systematic changes in tick bacterial microbiota diversity along elevational gradients. The observed patterns mirror diversity changes along elevational gradients typically observed in macroscopic taxa, and they highlight the key role of environmental factors in shaping within-host microbial communities in ectotherms.
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Affiliation(s)
- Tuomas Aivelo
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Zurich, Switzerland.
- Organismal and Evolutionary Biology Research Program, University of Helsinki, Viikinkaari 1 (PL 56), 00014, Helsinki, Finland.
| | - Mélissa Lemoine
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Zurich, Switzerland
| | - Barbara Tschirren
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK
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A climate-based model for tick life cycle: positive semigroup theory on Cauchy problem approach. J Math Biol 2022; 84:52. [DOI: 10.1007/s00285-022-01755-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 01/10/2022] [Accepted: 04/03/2022] [Indexed: 10/18/2022]
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Abstract
SUMMARYTicks are vectors of pathogens which are important both with respect to human health and economically. They have a complex life cycle requiring several blood meals throughout their life. These blood meals take place on different individual hosts and potentially on different host species. Their life cycle is also dependent on environmental conditions such as the temperature and habitat type. Mathematical models have been used for the more than 30 years to help us understand how tick dynamics are dependent on these environmental factors and host availability. In this paper, we review models of tick dynamics and summarize the main results. This summary is split into two parts, one which looks at tick dynamics and one which looks at tick-borne pathogens. In general, the models of tick dynamics are used to determine when the peak in tick densities is likely to occur in the year and how that changes with environmental conditions. The models of tick-borne pathogens focus more on the conditions under which the pathogen can persist and how host population densities might be manipulated to control these pathogens. In the final section of the paper, we identify gaps in the current knowledge and future modelling approaches. These include spatial models linked to environmental information and Geographic Information System maps, and development of new modelling techniques which model tick densities per host more explicitly.
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Daniel M, Malý M, Danielová V, Kříž B, Nuttall P. Abiotic predictors and annual seasonal dynamics of Ixodes ricinus, the major disease vector of Central Europe. Parasit Vectors 2015; 8:478. [PMID: 26385470 PMCID: PMC4575455 DOI: 10.1186/s13071-015-1092-y] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 09/11/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Abiotic conditions provide cues that drive tick questing activity. Defining these cues is critical in predicting biting risk, and in forecasting climate change impacts on tick populations. This is particularly important for Ixodes ricinus nymphs, the vector of numerous pathogens affecting humans. METHODS A 6-year study of the questing activity of I. ricinus was conducted in Central Bohemia, Czech Republic, from 2001 to 2006. Tick numbers were determined by weekly flagging the vegetation in a defined 600 m(2) field site. After capture, ticks were released back to where they were found. Concurrent temperature data and relative humidity were collected in the microhabitat and at a nearby meteorological station. Data were analysed by regression methods. RESULTS During 208 monitoring visits, a total of 21,623 ticks were recorded. Larvae, nymphs, and adults showed typical bimodal questing activity curves with major spring peaks and minor late summer or autumn peaks (mid-summer for males). Questing activity of nymphs and adults began with ~12 h of daylight and ceased at ~9 h daylight, at limiting temperatures close to freezing (in early spring and late autumn); questing occurred during ~70 % calendar year without cessation in summer. The co-occurrence of larvae and nymphs varied annually, ranging from 31 to 80 % of monitoring visits, and depended on the questing activity of larvae. Near-ground temperature, day length, and relative air humidity were all significant predictors of nymphal activity. For 70 % of records, near-ground temperatures measured in the microhabitat were 4-5 °C lower than those recorded by the nearby meteorological observatory, although they were strongly dependent. Inter-annual differences in seasonal numbers of nymphs reflected extreme weather events. CONCLUSIONS Weather predictions (particularly for temperature) combined with daylight length, are good predictors of the initiation and cessation of I. ricinus nymph questing activity, and hence of the risk period to humans, in Central Europe. Co-occurrence data for larvae and nymphs support the notion of intrastadial rather than interstadial co-feeding pathogen transmission. Annual questing tick numbers recover quickly from the impact of extreme weather events.
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Affiliation(s)
- Milan Daniel
- National Institute of Public Health, Prague, Czech Republic.
| | - Marek Malý
- National Institute of Public Health, Prague, Czech Republic.
| | | | - Bohumír Kříž
- National Institute of Public Health, Prague, Czech Republic.
| | - Patricia Nuttall
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK.
- NERC Centre for Ecology & Hydrology, Wallingford, Oxfordshire, UK.
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Hoch T, Monnet Y, Agoulon A. Influence of host migration between woodland and pasture on the population dynamics of the tick Ixodes ricinus: A modelling approach. Ecol Modell 2010. [DOI: 10.1016/j.ecolmodel.2010.04.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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8
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Effects of climate change on ticks and tick-borne diseases in europe. Interdiscip Perspect Infect Dis 2009; 2009:593232. [PMID: 19277106 PMCID: PMC2648658 DOI: 10.1155/2009/593232] [Citation(s) in RCA: 399] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Accepted: 09/18/2008] [Indexed: 11/18/2022] Open
Abstract
Zoonotic tick-borne diseases are an increasing health burden in Europe and there is speculation that this is partly due to climate change affecting vector biology and disease transmission. Data on the vector tick Ixodes ricinus suggest that an extension of its northern and altitude range has been accompanied by an increased prevalence of tick-borne encephalitis. Climate change may also be partly responsible for the change in distribution of Dermacentor reticulatus. Increased winter activity of I. ricinus is probably due to warmer winters and a retrospective study suggests that hotter summers will change the dynamics and pattern of seasonal activity, resulting in the bulk of the tick population becoming active in the latter part of the year. Climate suitability models predict that eight important tick species are likely to establish more northern permanent populations in a climate-warming scenario. However, the complex ecology and epidemiology of such tick-borne diseases as Lyme borreliosis and tick-borne encephalitis make it difficult to implicate climate change as the main cause of their increasing prevalence. Climate change models are required that take account of the dynamic biological processes involved in vector abundance and pathogen transmission in order to predict future tick-borne disease scenarios.
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The vertical distribution, density and the development of the tick Ixodes ricinus in mountain areas influenced by climate changes (The Krkonoše Mts., Czech Republic). Int J Med Microbiol 2008. [DOI: 10.1016/j.ijmm.2008.05.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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10
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Gray JS. Ixodes ricinus seasonal activity: Implications of global warming indicated by revisiting tick and weather data. Int J Med Microbiol 2008. [DOI: 10.1016/j.ijmm.2007.09.005] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Onyiah L, Arslan O. Simulating the development period of a parasite of sheep on pasture under varying temperature conditions. J Therm Biol 2005. [DOI: 10.1016/j.jtherbio.2004.10.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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12
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Ogden NH, Lindsay LR, Beauchamp G, Charron D, Maarouf A, O'Callaghan CJ, Waltner-Toews D, Barker IK. Investigation of relationships between temperature and developmental rates of tick Ixodes scapularis (Acari: Ixodidae) in the laboratory and field. JOURNAL OF MEDICAL ENTOMOLOGY 2004; 41:622-633. [PMID: 15311453 DOI: 10.1603/0022-2585-41.4.622] [Citation(s) in RCA: 144] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Relationships between temperature and preoviposition, preeclosion, and premolt developmental periods for the tick Ixodes scapularis Say were investigated by holding field-collected ticks in the laboratory at temperatures of 0 to 32 degrees C at constant daylength. The duration of these developmental periods decreased significantly with increasing temperature. Host of origin, prior storage at 4 degrees C, and season of collection of the ticks were also significantly associated with variations in the duration of the preoviposition period. For each developmental stage, the effect of temperature on development rate was best described as a power relationship. Laboratory-derived relationships were used to predict dates for molting, oviposition, and eclosion of engorged larvae and nymphs, engorged adult females and egg masses, respectively, placed in the field during 1989-1992. Predicted dates for oviposition by adult females, eclosion of eggs, and molting of engorged larvae were within 2 wk of the observed dates, and field-observed seasonal activity of questing larvae and nymphs also was predicted well by laboratory data. Molting of engorged nymphs and seasonal activity of questing adult ticks were, however, poorly predicted. Our findings suggest that duration of development in the field, of larvae from engorged adult females, and of nymphs from engorged larvae, may be explained largely by temperature effects alone, whereas emergence of adult I. scapularis from engorged nymphs may depend on temperature-independent diapause phenomena. The significance of these findings for understanding current and future distributions of I. scapularis, and of the pathogens it transmits, is discussed.
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Affiliation(s)
- N H Ogden
- Groupe de Recherche en Epidémiologie et Santé Publique, Faculté de Médecine Vétérinaire, Université de Montréal, Québec, Canada.
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Speybroeck N, Madder M, Van Den Bossche P, Mtambo J, Berkvens N, Chaka G, Mulumba M, Brandt J, Tirry L, Berkvens D. Distribution and phenology of ixodid ticks in southern Zambia. MEDICAL AND VETERINARY ENTOMOLOGY 2002; 16:430-441. [PMID: 12510896 DOI: 10.1046/j.1365-2915.2002.00397.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Distribution data for epidemiologically important ticks (Acari: Ixodidae) in the Southern Province of Zambia, one of the main cattle areas of the country, are presented. Boophilus microplus (Canestrini) was not recorded in southern Zambia, whereas Boophilus decoloratus (Koch) is present throughout the area. New distribution patterns for less economically important ixodid ticks are also discussed. Southern Zambia is a transition zone because it is the most northern area in Africa where mixed Rhipicephalus appendiculatus Neumann and Rhipicephalus zambeziensis Walker, Norval & Corwin populations were reported. Although a second generation of adult R. appendiculatus/R. zamnbeziensis was encountered, simulations indicated that this phenomenon is very rare in southern Zambia, mainly because of the colder temperatures during the early dry season and lower rainfall. These simulations were supported by a development trial under experimental conditions. Tick body size measurements showed that southern Zambian ticks are larger than eastern Zambian R. appendiculatus. It is hypothesized that body size is related to diapausing intensity in this species. The epidemiological consequences are that a different approach to control Theileria parva (Theiler) (Piroplasmida: Theileriidae) and other tick-borne diseases is needed in southern Zambia, compared to the one adopted in eastern Zambia.
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Affiliation(s)
- N Speybroeck
- Institute for Tropical Medicine, Department of Animal Health, Antwerpen, Belgium.
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Randolph SE, Green RM, Hoodless AN, Peacey MF. An empirical quantitative framework for the seasonal population dynamics of the tick Ixodes ricinus. Int J Parasitol 2002; 32:979-89. [PMID: 12076627 DOI: 10.1016/s0020-7519(02)00030-9] [Citation(s) in RCA: 206] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The wide geographic and climatic range of the tick Ixodes ricinus, and the consequent marked variation in its seasonal population dynamics, have a direct impact on the transmission dynamics of the many pathogens vectored by this tick species. We use long-term observations on the seasonal abundance and fat contents (a marker of physiological ageing) of ticks, and contemporaneous microclimate at three field sites in the UK, to establish a simple quantitative framework for the phenology (i.e. seasonal cycle of development) of I. ricinus as a foundation for a generic population model. An hour-degree tick inter-stadial development model, driven by soil temperature and including diapause, predicts the recruitment (i.e. emergence from the previous stage) of a single cohort of each stage of ticks each year in the autumn. The timing of predicted emergence coincides exactly with the new appearance of high-fat nymphs and adults in the autumn. Thereafter, fat contents declined steadily until unfed ticks with very low energy reserves disappeared from the questing population within about 1 year from their recruitment. Very few newly emerged ticks were counted on the vegetation in the autumn, but they appeared in increasing numbers through the following spring. Larger ticks became active and subsequently left the questing population before smaller ones. Questing tick population dynamics are determined by seasonal patterns of tick behaviour, host-contact rates and mortality rates, superimposed on a basal phenology that is much less complex than has hitherto been portrayed.
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Affiliation(s)
- Sarah E Randolph
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
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Mwambi HG, Baumgärtner J, Hadeler KP. Ticks and tick-borne diseases: a vector-host interaction model for the brown ear tick (Rhipicephalus appendiculatus). Stat Methods Med Res 2000; 9:279-301. [PMID: 11084709 DOI: 10.1177/096228020000900307] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
An analytical model is derived for the interaction of the brown ear tick (Rhipicephalus appendiculatus) with its hosts. Such models are rare due to the complexity and lack of information on the entire stages of ticks life cycles. Most models are simulations rather than analytical. The vector is categorized into a discrete number of compartments according to its life cycle. The starting model in this article consists of a system of differential equations with constant coefficients. A general model on a stage structured population with unlimited host density is developed. From the characteristic polynomial of the system a sensitivity analysis for the population parameters is carried out in detail. The model is then improved by incorporating host abundance and availability. This is done on the basis of a demand-driven and ratio-dependent functional response model. The improved model adequately represents the dynamics of a stage-structured vector population under conditions of varying host density. The model allows the qualitative evaluation of several management strategies and is expected to guide future research work.
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Affiliation(s)
- H G Mwambi
- Department of Mathematics, University of Nairobi, Kenya.
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King D, Gettinby G, Newson RM. A climate-based model for the development of the ixodid tick, Rhipicephalus appendiculatus in East Coast fever zones. Vet Parasitol 1988; 29:41-51. [PMID: 3176300 DOI: 10.1016/0304-4017(88)90006-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
East Coast fever (Theileria parva infection) is an important parasitic disease of cattle in East and Central Africa. Past experimental studies have provided a great deal of information on the dynamics of the life cycle of the tick vector, Rhipicephalus appendiculatus. This paper describes a mathematical model based on field observations to explain the close relationship between the tick life cycle and climate. The model provides a basis for the future study of different ECF control programmes using computer experiments.
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Affiliation(s)
- D King
- Department of Mathematics, University of Strathclyde, Glasgow, Gt. Britain
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17
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Gardiner WP, Gray JS. A computer simulation of the effects of specific environmental factors on the development of the sheep tick Ixodes ricinus L. Vet Parasitol 1986; 19:133-44. [PMID: 3962155 DOI: 10.1016/0304-4017(86)90041-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A previously developed technique for predicting field development rates of the tick, Ixodes ricinus, has been modified and used in an attempt to test interpretations of field data and to gain further insight into the population dynamics of I. ricinus. The results of this study have provided encouraging evidence of the validity of the predictive technique, identified certain areas in the biology of I. ricinus which require further investigation and, in general, supported the suggestion that in Ireland a continuous interchange of ticks between spring and autumn populations occurs. This technique requires further refinement but it appears to have considerable potential for predicting the behaviour of tick populations in different localities and under the influence of different weather conditions.
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18
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Gardiner WP, Gettinby G. A weather-based prediction model for the life-cycle of the sheep tick, Ixodes ricinus L. Vet Parasitol 1983; 13:77-84. [PMID: 6684828 DOI: 10.1016/0304-4017(83)90022-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The incidence of sheep tick activity depends not only on the climatic conditions within the tick habitat, but also on the rates of fecundity, development, activity, engorgement and mortality of each stage of the life-cycle. Use of existing experimental results on the effect of these factors enables a model of the life-cycle to be formulated for the purpose of predicting the occurrence of tick activity in the field where climatic conditions vary. The components of such a model are described and the predicted results compared with field studies carried out in Ireland. It is hoped that the model presented will show the potential of formulating a system for predicting tick activity. Such a system could be used to enhance the control of tick-transmitted diseases.
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19
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The role of temperature and other factors in predicting the pattern of bovine Ostertagia spp. Infective larvae on pasture. J Therm Biol 1981. [DOI: 10.1016/0306-4565(81)90031-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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