RESUMEN
Using specific primers based on the ribosomal operon, positive DNA amplification was obtained from lungs of 11/215 tested small burrowing animals, both terrestrial and aquatic, and including frozen (n = 4) and formalin-fixed paraffin-embedded (n = 7) samples. The main species detected in Europe in mice, otters and river rats was Emmonsia crescens. Two strains from otters and weasels were Blastomyces parvus. Two Australian wombats revealed the presence of a hitherto unknown species of the geophilic genus Emmonsiellopsis.
Asunto(s)
Animales Salvajes/microbiología , Chrysosporium/clasificación , Chrysosporium/genética , Patología Molecular/métodos , Animales , Blastomyces/clasificación , Blastomyces/genética , Ratones , Mustelidae/microbiología , RatasRESUMEN
Dobrava-Belgrade virus (DOBV) is the most pathogenic hantavirus in Europe with a case-fatality rate of up to 12%. To detect changes in risk for humans, the prevalence of antibodies to DOBV has been monitored in a population of Apodemus flavicollis in the province of Trento (northern Italy) since 2000, and a sudden increase was observed in 2010. In the 13-year period of this study, 2077 animals were live-trapped and mean hantavirus seroprevalence was 2·7% (s.e. = 0·3%), ranging from 0% (in 2000, 2002 and 2003) to 12·5% (in 2012). Climatic (temperature and precipitation) and host (rodent population density, rodent weight and sex, and larval tick burden) variables were analysed using Generalized Linear Models and multi-model inference to select the best model. Climatic changes (mean annual precipitation and maximum temperature) and individual body mass had a positive effect on hantavirus seroprevalence. Other possible drivers affecting the observed pattern need to be studied further.
Asunto(s)
Anticuerpos Antivirales/sangre , Infecciones por Hantavirus/veterinaria , Murinae , Orthohantavirus/inmunología , Enfermedades de los Roedores/epidemiología , Enfermedades de los Roedores/virología , Animales , Peso Corporal , Clima , Femenino , Infecciones por Hantavirus/epidemiología , Italia/epidemiología , Masculino , Estudios SeroepidemiológicosRESUMEN
West Nile virus (WNV) is continuously spreading across Europe, and other continents, i.e. North and South America and many other regions of the world. Despite the overall sporadic nature of outbreaks with cases of West Nile neuroinvasive disease (WNND) in Europe, the spillover events have increased and the virus has been introduced into new areas. The high genetic diversity of the virus, with remarkable phenotypic variation, and its endemic circulation in several countries, require an intensification of the integrated and multidisciplinary research efforts built under the 7th Framework Programme of the European Union (FP7). It is important to better clarify several aspects of WNV circulation in Europe, including its ecology, genomic diversity, pathogenicity, transmissibility, diagnosis and control options, under different environmental and socio-economic scenarios. Identifying WNV endemic as well as infection-free areas is becoming a need for the development of human vaccines and therapeutics and the application of blood and organs safety regulations. This review, produced as a joint initiative among European experts and based on analysis of 118 scientific papers published between 2004 and 2014, provides the state of knowledge on WNV and highlights the existing knowledge and research gaps that need to be addressed with high priority in Europe and neighbouring countries.
Asunto(s)
Conocimientos, Actitudes y Práctica en Salud , Investigación , Virus del Nilo Occidental/genética , Brotes de Enfermedades/prevención & control , Europa (Continente)/epidemiología , Variación Genética , Humanos , Filogenia , Vigilancia de la Población , Fiebre del Nilo Occidental/epidemiología , Virus del Nilo Occidental/aislamiento & purificación , Virus del Nilo Occidental/patogenicidadRESUMEN
We examined the relative importance of intrinsic host factors and microparasite co-infection in generating variation in Heligmosomoides polygyrus fecundity, a parameter that serves as a proxy for infectiousness. We undertook extensive trapping of Apodemus flavicollis, the yellow-necked mouse in the woodlands of the Italian Alps and recorded eggs in utero from the dominant nematode species H. polygyrus, and tested for the presence of five microparasite infections. The results showed that sex and breeding status interact, such that males in breeding condition harboured more fecund nematodes than other hosts; in particular, worms from breeding males had, on average, 52% more eggs in utero than worms from non-breeding males. In contrast, we found a weak relationship between intensity and body mass, and no relationship between intensity and sex or intensity and breeding condition. We did not find any evidence to support the hypothesis that co-infection with microparasites contributed to variation in worm fecundity in this system. The age-intensity profiles for mice singly-infected with H. polygyrus and those co-infected with the nematode and at least one microparasite were both convex and not statistically different from each other. We concluded that intrinsic differences between hosts, specifically with regard to sex and breeding condition, contribute relatively more to the variation in worm fecundity than parasite co-infection status.
Asunto(s)
Murinae/parasitología , Nematospiroides dubius/fisiología , Infecciones por Strongylida/parasitología , Distribución por Edad , Animales , Femenino , Fertilidad , Interacciones Huésped-Parásitos , MasculinoRESUMEN
Free-living animals are usually inhabited by a community of parasitic species that can interact with each other and alter both host susceptibility and parasite transmission. In this study we tested the prediction that an increase in the gastrointestinal nematode Heligmosomoides polygyrus would increase the infestation of the tick Ixodes ricinus, in free-living yellow-necked mice, Apodemus flavicollis. An extensive cross-sectional trapping survey identified a negative relationship between H. polygyrus and I. ricinus counter to the prediction. An experimental reduction of the nematode infection through anthelmintic treatment resulted in an increase in tick infestation, suggesting that this negative association was one of cause and effect. Host characteristics (breeding condition and age) and habitat variables also contributed to affect tick infestation. While these results were counter to the prediction, they still support the hypothesis that interactions between parasite species can shape parasite community dynamics in natural systems. Laboratory models may act differently from natural populations and the mechanism generating the negative association is discussed.
Asunto(s)
Ixodes/patogenicidad , Murinae/parasitología , Nematospiroides dubius/patogenicidad , Enfermedades de los Roedores , Infecciones por Strongylida , Infestaciones por Garrapatas , Animales , Femenino , Interacciones Huésped-Parásitos , Ixodes/crecimiento & desarrollo , Masculino , Nematospiroides dubius/crecimiento & desarrollo , Dinámica Poblacional , Enfermedades de los Roedores/inmunología , Enfermedades de los Roedores/parasitología , Infecciones por Strongylida/complicaciones , Infecciones por Strongylida/parasitología , Infecciones por Strongylida/veterinaria , Infestaciones por Garrapatas/complicaciones , Infestaciones por Garrapatas/parasitología , Infestaciones por Garrapatas/veterinariaRESUMEN
The arrival of infected travelers from endemic regions can trigger sustained autochthonous transmission of mosquito-borne pathogens in Europe. In 2007 a Chikungunya outbreak was observed in central Italy, mostly affecting two villages characterised by a high density of Aedes albopictus. The outbreak was mitigated through intervention strategies reducing the mosquito abundance. Ten years later, in 2017, sustained Chikungunya transmission was documented in both central and southern Italy. The proposed analysis identifies suitable reactive measures for the containment and mitigation of future epidemics by combining epidemiological modeling with a health economic approach, considering different arrival times of imported infections and possible delays in the notification of cases. Obtained estimates suggest that, if the first notification will occur in the middle of the mosquito breeding season, the combination of larvicides, adulticides and breeding sites removal represents the optimal strategy. In particular, we found that interventions implemented in 2007 were cost-effective, with about 3200 prevented cases, 1450 DALYs averted and 13.5 M saved. Moreover, larvicides are proven to be more cost beneficial in early summer and warmer seasons, while adulticides should be preferred in autumn and colder seasons. Our results provide useful indications supporting urgent decision-making of public health authorities in response to emerging mosquito-borne epidemics.
Asunto(s)
Fiebre Chikungunya/prevención & control , Brotes de Enfermedades/prevención & control , Insecticidas/farmacología , Control de Mosquitos/métodos , Mosquitos Vectores/efectos de los fármacos , Animales , Fiebre Chikungunya/transmisión , Fiebre Chikungunya/virología , Análisis Costo-Beneficio , Humanos , Italia/epidemiología , Larva/efectos de los fármacos , Larva/crecimiento & desarrollo , Control de Mosquitos/economía , Mosquitos Vectores/fisiología , Salud Pública/economía , Salud Pública/métodos , Estaciones del AñoRESUMEN
Aedes koreicus (Edwards) is an invasive mosquito species, like Aedes albopictus (Skuse) and Aedes japonicus japonicus (Theobald), that has already colonized a large part of northeastern Italy and other European countries. Despite its rapid expansion, information about adult distribution and trapping is lacking. Here, we conducted a 2-yr longitudinal survey using adult traps to investigate the spatiotemporal distribution of Ae. koreicus and evaluated the effectiveness of three trapping devices in Latin square experiments conducted in an urban site and a forested site. The following three different traps were compared: a CO2-baited Biogents (BG) Sentinel trap, a CO2-baited Centers for Disease Control and Prevention light trap (CDC trap), and a grass infusion-baited gravid trap.In northern Italy, Ae. koreicus was collected from late April to early November, with peak of abundance observed in August. Aedes koreicus was more abundant in 2015 than in 2014 because of higher temperatures during summer. Unlike Ae. albopictus, the abundance of Ae. koreicus was not related to the altitude of the sampling locations in the range 241-660 m above sea level. The BG Sentinel and gravid traps collected significantly more Ae. koreicus than the CDC trap in the urban site, whereas there was no significant difference between the three traps in the forested site. In the urban site, the BG Sentinel trap and the gravid trap were the most effective for collecting Ae. albopictus and Culex pipiens L., respectively. In the forested site, Cx. pipiens was primarily collected by the CDC trap.
Asunto(s)
Aedes/fisiología , Distribución Animal , Culex/fisiología , Animales , Femenino , Italia , Masculino , Control de Mosquitos/instrumentación , Dinámica Poblacional , Estaciones del AñoAsunto(s)
Vectores Arácnidos/microbiología , Ixodes/microbiología , Enfermedad de Lyme , Animales , Vectores Arácnidos/clasificación , Borrelia burgdorferi/aislamiento & purificación , Europa (Continente)/epidemiología , Humanos , Incidencia , Ixodes/clasificación , Enfermedad de Lyme/diagnóstico , Enfermedad de Lyme/epidemiología , Enfermedad de Lyme/microbiología , Enfermedad de Lyme/prevención & control , Enfermedad de Lyme/transmisión , Factores de Riesgo , Pruebas SerológicasRESUMEN
The most important tick-deer system potentially supporting the epidemiology of Lyme disease in the Italian Alps is that regarding Ixodes ricinus (L.) and roe deer (Capreolus capreolus L.). In this study, the pattern of tick infestation on 562 male roe deer harvested in September 1994 in 56 game districts of Trentino, Northern Italy, was assessed. The prevalence and density of infestation by I. ricinus were analyzed by a model based on classification and regression trees (CART), using both discrete and continuous variables concerning environmental and host parameters. The model discriminated attitude and host density as the 2 variables having the greatest effect on the prevalence and density of infestation of deer; the levels of infestation were higher at an altitude below 1125 m or at roe deer densities over 8.5 head per 100 ha. The density of tick infestation tended to be higher in older roe deer.
Asunto(s)
Ciervos/parasitología , Ixodes , Infestaciones por Garrapatas/veterinaria , Factores de Edad , Altitud , Animales , Vectores Arácnidos , Reservorios de Enfermedades , Italia/epidemiología , Enfermedad de Lyme/epidemiología , Modelos Teóricos , Infestaciones por Garrapatas/epidemiologíaRESUMEN
A preliminary survey of the intestinal helminth community of rock partridge (Alectoris graeca saxatilis) was undertaken in the Italian province of Trentino where the host population exhibits cyclic fluctuations in abundance. Six helminth species were recorded from 38 rock partridge intestines collected during the hunting season between October and November 1994. Nematoda were the most prevalent (53%) with lower prevalence of Trematoda (11%) and Cestoda (8%). Ascaridia compar (Schrank, 1790) and Heterakis tenuicauda Linstow, 1883, were identified as the component species (each with prevalence > 10%) in the helminth intestinal community of rock partridge in Trentino. Both of these species exhibit an aggregated distribution.
Asunto(s)
Enfermedades de las Aves/epidemiología , Aves/parasitología , Helmintiasis Animal/epidemiología , Parasitosis Intestinales/veterinaria , Animales , Enfermedades de las Aves/parasitología , Helmintiasis Animal/parasitología , Parasitosis Intestinales/epidemiología , Parasitosis Intestinales/parasitología , Italia/epidemiología , Periodicidad , Dinámica Poblacional , Prevalencia , Especificidad de la EspecieRESUMEN
Populations of rock partridge (Alectoris graeca saxatilis), in the Trentino province of Italy, exhibit cyclic fluctuations in abundance associated with relatively dry habitat. One of the hypothesis to explain these cycles is that survival of some free living parasitic stages and rates of infection are greater in these areas leading to higher parasite burden. This hypothesis was examined by investigating the intensity of parasite infection in cyclic and non cyclic rock partridge populations. Analyses of 87 intestine samples collected from shot rock partridges during 1994 and 1995 identified 8 species of helminths parasites: Ascaridia compar (P = 33.33%; I = 9.28 +/- 1.78), Heterakis tenuicauda (P = 19.54%; I = 10.29 +/- 4.58), Heterakis gallinarum (P = 1.15%; I = 1.0 +/- 0.0), Heterakis altaica (P = 1.15%; I = 17 +/- 0.0), Aonchoteca caudinflata (P = 6.89; I = 2.17 +/- 0.65), Postharmostomum commutatum (P = 5.75; I = 7.0 +/- 3.48), Brachylaema fuscata (P = 1.15; I = 7.0 +/- 0.0), Platynosomum alectoris (P = 2.29; I = 5.5 +/- 1.5). Cestoda, recorded with a prevalence of 5.75, were not identified to species level. A. compar and H. tenuicauda were prevalent in the rock partridge populations and there was no positive association between these species. Intensity of infection in both species was not influenced by host age, sex or year of study but levels of infection with A. compar burdens were significantly greater in cyclic populations than in non cyclic populations and there was a tendency for H. tenuicauda to be greater in cyclic populations. There was no negative relationship between intensity of infection with A. compar or H. tenuicauda and host body mass. These data provide some support for the hypothesis that these parasites may play a role in generating rock partridge population cycles.
Asunto(s)
Enfermedades de las Aves/epidemiología , Infecciones por Nematodos/veterinaria , Animales , Ascaridia/aislamiento & purificación , Aves , Cestodos/aislamiento & purificación , Femenino , Intestinos/parasitología , Italia/epidemiología , Masculino , Infecciones por Nematodos/epidemiología , PeriodicidadRESUMEN
The tick Ixodes ricinus has been recorded in most Italian regions especially in thermo-mesophilous woods and shrubby habitats where the relative humidity allow the tick to complete its 3 year developmental cycle, as predicted for the European climatic ranges. This tick acts both as vector and reservoir for a series of wildlife zoonotic pathogens, especially the agents of Lyme diseases, Tick borne encephalitis and Human Granulocytic Ehrlichiosis, which are emerging in most of Europe. To assess the spatial distribution of these pathogens and the infection risk for humans and animals within the territory of the Province of Trento, we carried out a long term study using a combination of eco-epidemiological surveys and mathematical modelling. An extensive tick collection with a GIS based habitat suitability analysis allowed us to identify the areas where tick occurs at various density. To identify the areas with higher infection risk, we estimated the values of R0 for Borrelia burgdorferi s.l., TBE virus and Anaplasma phagocytophila under different ecological conditions. We assessed the infection prevalence in the vector and in the wildlife reservoir species that play a central role in the persistence of these infections, ie the small mammals A. flavicollis and C. glareolus. We also considered the double effect of roe deer (Capreolus capreolus) which act as reservoir for A. phagocytophila but is an incompetent host for B. burgdorferi and TBE virus, thus reducing the infection prevalence in ticks of these last two pathogens. Infection prevalence with B. burgdorferi and A. phagocytophila in the vector was assessed by PCR screening 1212 I. ricinus nymphs collected by dragging in six main study areas during 2002. The mean infection prevalence recorded was 1.32% for B. burgdorferi s.l. and 9.84% for A. phagocytophila. Infection prevalence in nymphs with TBE virus, as assessed in a previous study was 0.03%. Infection prevalence in rodents was assessed by screening (with ELISA and PCR) tissues and blood samples collected from 367 rodent individuals trapped extensively during 2002 within 6 main study areas. A. flavicollis (N=238) was found to be infected with all three pathogens investigated, with infection prevalence ranging from 3.3% for TBE virus to 11.7% for A. phagocytophila, and 16.6% with B. burgdorferi s.l. C. glareolus (N=108) showed an infection prevalence of 6.5% with A. phagocytophila and 12.7% with B. burgdorferi s.l., while no individuals were infected with TBE virus. We also screened 98 spleen samples collected from roe deer with PCR, resulting in a mean prevalence of infection with A. phagocytophila of 19.8%. Using a deterministic model we explored the condition for diseases persistence under different rodent and roe deer densities. R0 values resulted largely above 1 for B. burgdorferi s.l. in the vast majority of the areas classified as suitable for I. ricinus occurrence in Trentino, while the condition for TBE persistence appeared to be more restricted by a combination of climatic condition and host densities.
Asunto(s)
Vectores Arácnidos/microbiología , Reservorios de Enfermedades , Ehrlichiosis/transmisión , Ixodes/microbiología , Enfermedad de Lyme/transmisión , Enfermedades por Picaduras de Garrapatas/transmisión , Anaplasma phagocytophilum/aislamiento & purificación , Animales , Animales Domésticos/parasitología , Animales Salvajes/parasitología , Vectores Arácnidos/virología , Mordeduras y Picaduras/complicaciones , Mordeduras y Picaduras/microbiología , Ciervos/microbiología , Ciervos/parasitología , Transmisión de Enfermedad Infecciosa , Ehrlichiosis/veterinaria , Encefalitis Transmitida por Garrapatas/epidemiología , Encefalitis Transmitida por Garrapatas/transmisión , Contaminación de Alimentos , Humanos , Italia/epidemiología , Ixodes/virología , Enfermedad de Lyme/epidemiología , Enfermedades Parasitarias en Animales/epidemiología , Enfermedades Parasitarias en Animales/transmisión , Infestaciones por Garrapatas/veterinaria , Enfermedades por Picaduras de Garrapatas/epidemiología , Árboles , ZoonosisRESUMEN
A homologous series of esters of beta-carboline-3-carboxylic acid was prepared by a new synthetic procedure. The first members of the series are convulsant or pro-convulsant agents while those with acyl residues longer than C4 show anticonvulsant activity. The affinity of the members of the series for the benzodiazepine receptor from rat brain decreases with the increasing chain length of the esters. The pentyl ester was studied in particular for its anti-convulsant effect on rats and mice treated with cardiazol. The compound also acts as a membrane stabilizer by inhibiting red cell hypotonic hemolysis and rat brain Na/K ATPase; its LD50 value is 12.5 mg/Kg and of particular interest is its lack of inhibitory effect on memory retention in mice at doses at which diazepam has inhibitory effects.
Asunto(s)
Anticonvulsivantes/síntesis química , Carbolinas/síntesis química , Ácidos Carboxílicos/síntesis química , Animales , Anticonvulsivantes/toxicidad , Reacción de Prevención/efectos de los fármacos , Carbolinas/farmacología , Carbolinas/toxicidad , Ácidos Carboxílicos/farmacología , Ácidos Carboxílicos/toxicidad , Fenómenos Químicos , Química , Ésteres/síntesis química , Ésteres/farmacología , Ésteres/toxicidad , Dosificación Letal Mediana , Masculino , Ratones , RatasRESUMEN
Tick-borne encephalitis is an emerging vector-borne zoonotic disease reported in several European and Asiatic countries with complex transmission routes that involve various vertebrate host species other than a tick vector. Understanding and quantifying the contribution of the different hosts involved in the TBE virus cycle is crucial in estimating the threshold conditions for virus emergence and spread. Some hosts, such as rodents, act both as feeding hosts for ticks and reservoirs of the infection. Other species, such as deer, provide important sources of blood for feeding ticks but they do not support TBE virus transmission, acting instead as dead-end (i.e., incompetent) hosts. Here, we introduce an eco-epidemiological model to explore the dynamics of tick populations and TBE virus infection in relation to the density of two key hosts. In particular, our aim is to validate and interpret in a robust theoretical framework the empirical findings regarding the effect of deer density on tick infestation on rodents and thus TBE virus occurrence from selected European foci. Model results show hump-shaped relationships between deer density and both feeding ticks on rodents and the basic reproduction number for TBE virus. This suggests that deer may act as tick amplifiers, but may also divert tick bites from competent hosts, thus diluting pathogen transmission. However, our model shows that the mechanism responsible for the dilution effect is more complex than the simple reduction of tick burden on competent hosts. Indeed, while the number of feeding ticks on rodents may increase with deer density, the proportion of blood meals on competent compared with incompetent hosts may decrease, triggering a decline in infection. As a consequence, using simply the number of ticks per rodent as a predictor of TBE transmission potential could be misleading if competent hosts share habitats with incompetent hosts.
Asunto(s)
Ciervos/crecimiento & desarrollo , Ciervos/parasitología , Encefalitis Transmitida por Garrapatas/epidemiología , Ixodes/crecimiento & desarrollo , Enfermedades de los Roedores/epidemiología , Infestaciones por Garrapatas/veterinaria , Zoonosis/transmisión , Animales , Reservorios de Enfermedades , Ecosistema , Europa (Continente)/epidemiología , Humanos , Modelos Estadísticos , Densidad de Población , Enfermedades de los Roedores/parasitología , Roedores , Infestaciones por Garrapatas/epidemiología , Infestaciones por Garrapatas/parasitología , Zoonosis/parasitologíaRESUMEN
Tick borne encephalitis (TBE) is endemic to eastern and central Europe with broad temporal and spatial variation in infection risk. Although many studies have focused on understanding the environmental and socio-economic factors affecting exposure of humans to TBE, comparatively little research has been devoted to assessing the underlying ecological mechanisms of TBE occurrence in enzootic cycles, and therefore TBE hazard. The aim of this study was to evaluate the effect of the main ungulate tick hosts on the pattern of tick infestation in rodents and TBE occurrence in rodents and questing adult ticks. In this empirical study, we considered three areas where endemic human TBE occurs and three control sites having no reported human TBE cases. In these six sites located in Italy and Slovakia, we assessed deer density using the pellet group count-plot sampling technique, collected questing ticks, live-trapped rodents (primarily Apodemus flavicollis and Myodes glareolus) and counted ticks feeding on rodents. Both rodents and questing ticks were screened for TBE infection. TBE infection in ticks and rodents was positively associated with the number of co-feeding ticks on rodents and negatively correlated with deer density. We hypothesise that the negative relationship between deer density and TBE occurrence on a local scale (defined by the minimum overlapping area of host species) could be attributed to deer (incompetent hosts) diverting questing ticks from rodents (competent hosts), know as the 'dilution effect hypothesis'. We observed that, after an initial increase, the number of ticks feeding on rodents reached a peak for an intermediate value of estimated deer density and then decreased. Therefore, while at a regional scale, tick host availability has already been shown to be directly correlated with TBE distribution, our results suggest that the interactions between deer, rodents and ticks are much more complex on a local scale, supporting the possibility of a dilution effect for TBE.
Asunto(s)
Ciervos/parasitología , Virus de la Encefalitis Transmitidos por Garrapatas/aislamiento & purificación , Ixodes/crecimiento & desarrollo , Enfermedades de los Roedores/epidemiología , Infestaciones por Garrapatas/veterinaria , Animales , Ecosistema , Italia , Ixodes/virología , Densidad de Población , Enfermedades de los Roedores/parasitología , Roedores , Eslovaquia , Infestaciones por Garrapatas/epidemiología , Infestaciones por Garrapatas/parasitologíaRESUMEN
The wood tick Ixodes ricinus, one of the most common arthropod-borne disease vectors, is of increasing relevance for human and animal health in Europe. The aim of this study was to determine the relative contribution of several abiotic and biotic factors potentially affecting questing activity and local abundance of I. ricinus in Italy, considering the scale at which these factors interact with the host-seeking ticks. Within EDEN, a large-scale EU collaborative project on eco-epidemiology of vector-borne diseases, we collected questing ticks for three consecutive years using a standard protocol at eleven sites in the Italian Alps and Apennines. A total of 25 447 I. ricinus were collected. All sites showed the same annual pattern of tick activity (bimodal for nymphs and unimodal for larvae and adults), although the abundance of nymphs was statistically different between sites and years. A Generalized Linear Mixed Model and a Linear Mixed Model fitted to data for nymphs, showed that while the principal variables affecting the local abundance of questing ticks were saturation deficit (an index combining temperature and relative humidity) and red deer density, the most important variable affecting questing nymph activity was saturation deficit. As for the timing of seasonal emergence, we confirmed that the threshold temperature at this latitude for larvae is 10°C (mean maximum) while that for nymphs is 8°C.