Browsing by Subject "tick"
Now showing items 1-3 of 3
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(2023)Punkkivälitteiset patogeenit (PVP) ovat yleisimpiä zoonoottisten tartuntojen aiheuttajia Suomessa. Tautitaakkaan vaikuttavat erityisesti Borrelia burgdorferi sensu lato -bakteerien (BBSL) ja puutiaisaivokuumeviruksen (TBEV) aiheuttamat tartunnat. Molemmat ovat lisääntyneet Suomessa viime vuosikymmeninä. Tapausten lisääntymisen voi pääosin laskea taudinaiheuttajien päävektorien, puutiaisen (Ixodes ricinus) ja taigapunkin (I. persulcatus), levittäytymisen ansioksi. Ulkoloisina punkit välittävät tauteja useisiin selkärankaisiin ruokinnan yhteydessä. Ankarat talvet ovat rajoittaneet punkkien levittäytymistä pohjoiseen, mutta ilmastonmuutoksen aiheuttamat leudommat talvikelit ovat edistäneet valloitusretkeä uusille alueille. Vaikka sopiva ilmasto on olennaista punkkien esiintyvyydelle, vaikuttaa punkkien isäntälajiston rakenne mitä luultavimmin punkkien ja PVP:ien yleisyyteen paikallisella tasolla. Tässä tutkielmassa punkkeja kerättiin 6 aitausalueelta ja niiden ympäristöstä. Samoilta alueilta määritettiin lisäksi piennisäkkäiden ja hirvieläinten määrät. Koska aitaukset ja niiden ympäristöt luultavasti edustavat samankaltaista ilmastoa, pyrittiin tutkielmassa tutkia, kuinka punkki-isäntiin liittyvät tekijät vaikuttavat punkkien ja PVP:ien esiintyvyyteen. TBEV-positiivisen poolin sekä TBEV-vasta-aineita kantavien piennisäkkäiden perusteella Hangossa varmistettiin mahdollisesti uusi TBEV pesäke. Aitausten, piennisäkäsmäärien ja hirvieläintiheyksien pohjilta luotiin yleistettyjä lineaarisia sekamalleja (GLMM) selittämään punkkien ja PVP:ien esiintyvyyttä tutkimusalueilla. TBEV jätettiin mallinnuksen ulkopuolelle pienen otoskoon takia. Hirvieläintiheydet olivat erittäin merkitsevä punkkien esiintyvyyteen vaikuttava tekijä. BBSL:n yleisyyteen ei yksikään tekijä vaikuttanut merkitsevällä tasolla – mahdollisena syynä piennisäkäspopulaatioiden muutoksen viiveellinen heijastuminen kerättyjen punkkien tartunta-asteeseen.
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(2022)Crimean Congo haemorrhagic fever (CCHF) is an emerging, tick-borne viral pathogen. Found on three continents, it is the most widespread of all tick-borne pathogens, but accurate geographical limits and epidemiology in Africa are still mostly unknown. Ticks act as both vectors and reservoirs, and the transmission cycle involves both wild and domestic animals and may occasionally spill over to humans. Further healthcare-related infections from human to human are common. With a high mortality rate and no cure or vaccine, CCHF is considered a major public health threat in endemic countries. This licentiate thesis consists of a literature review and an experimental work section. The literature review covers the basics of tick ecology, tick-borne diseases and viral haemorrhagic fevers with a focus on Africa and Kenya. These are used as foundations to understand CCHF in detail, encompassing virology, epidemiology, diagnostics, symptoms, treatment and prevention. The experimental work entails PCR-screening of ticks collected from South-eastern Kenya for the CCHF virus. The main objective of the study was to find whether CCHF is circulating in free-roaming ticks collected from two conservancies in the Taita Hills area. Taita Hills are located in Taita-Taveta county, near the Helsinki University research centre in Wundanyi. The ticks were collected by the Vapalahti virology team in 2018. This thesis involved the RNA extraction and measurement from the ticks and screening for CCHF virus with RT-qPCR. The results were negative for all 57 units of ticks processed. The study was a part of a larger research project, “Preparedness for emerging zoonotic infections in Kenya”. Previous publications on CCHF are lacking from this part of Kenya, so this study was a valuable part of primary research to establish the geographical limits and members of the enzootic cycle in Taita Hills. It would be essential to continue examining ticks from animal sources in addition to human serology, to further establish evidence of possible CCHF occurrence in the area. Mapping the prevalence and epidemiology of zoonotic and tick-borne pathogens is especially critical now, when climate change and diminishing biodiversity stir and alter disease emergence in an unprecedented manner.
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(2022)Crimean Congo haemorrhagic fever (CCHF) is an emerging, tick-borne viral pathogen. Found on three continents, it is the most widespread of all tick-borne pathogens, but accurate geographical limits and epidemiology in Africa are still mostly unknown. Ticks act as both vectors and reservoirs, and the transmission cycle involves both wild and domestic animals and may occasionally spill over to humans. Further healthcare-related infections from human to human are common. With a high mortality rate and no cure or vaccine, CCHF is considered a major public health threat in endemic countries. This licentiate thesis consists of a literature review and an experimental work section. The literature review covers the basics of tick ecology, tick-borne diseases and viral haemorrhagic fevers with a focus on Africa and Kenya. These are used as foundations to understand CCHF in detail, encompassing virology, epidemiology, diagnostics, symptoms, treatment and prevention. The experimental work entails PCR-screening of ticks collected from South-eastern Kenya for the CCHF virus. The main objective of the study was to find whether CCHF is circulating in free-roaming ticks collected from two conservancies in the Taita Hills area. Taita Hills are located in Taita-Taveta county, near the Helsinki University research centre in Wundanyi. The ticks were collected by the Vapalahti virology team in 2018. This thesis involved the RNA extraction and measurement from the ticks and screening for CCHF virus with RT-qPCR. The results were negative for all 57 units of ticks processed. The study was a part of a larger research project, “Preparedness for emerging zoonotic infections in Kenya”. Previous publications on CCHF are lacking from this part of Kenya, so this study was a valuable part of primary research to establish the geographical limits and members of the enzootic cycle in Taita Hills. It would be essential to continue examining ticks from animal sources in addition to human serology, to further establish evidence of possible CCHF occurrence in the area. Mapping the prevalence and epidemiology of zoonotic and tick-borne pathogens is especially critical now, when climate change and diminishing biodiversity stir and alter disease emergence in an unprecedented manner.
Now showing items 1-3 of 3