Search

Background: Bulinus globosus, the main intermediate snail host of Schistosoma haematobium. The increased contacts between Africa and China could even lead to large-scale dissemination of B. globosus in China. Temperature is the key factor affecting fresh-water snail transmission. This study predicted potential risk of colonization of B. globosus in the mainland of China under climate change. Methods: We investigated minimum and maximum temperatures for B. globosus eggs, juveniles and adult snails kept under laboratory conditions to find the most suitable range by pinpointing the median effective temperatures (ET50). We also assessed the influence of temperature on spawning and estimated the accumulated temperature (AT). The average air temperatures between 1955 and 2019 in January and July, the coldest and hottest months in China, respectively, were collected from national meteorological monitoring stations and investigated in a geographic information system (GIS) using empirical Bayesian Kriging to evaluate the theoretical possibility for distribution of B. globosus in southern China based on temperature. Results: The effective minimum temperature (ET50min) for eggs, juveniles, adult snails and spawning were 8.5, 7.0, 7.0, 14.9 °C, respectively, with the corresponding maximum values (ET50max) of 36.6, 40.5, 40.2 and 38.1 °C. The AT was calculated at 712.1 ± 64.9 °C·d. In 1955, the potential B. globosus distribution would have had a northern boundary stretching from the coastal areas of Guangdong Province and Guangxi Autonomous Region to southern Yunnan Province. Since then, this line has gradually moved northward. Conclusions: Annual regeneration of B. globosus can be supported by the current climate conditions in the mainland of China, and a gradual expansion trend from south to north is shown in the study from 2015 to 2019. Thus, there is a potential risk of colonization of B. globosus in the mainland of China under climate change. [ABSTRACT FROM AUTHOR]

[Display omitted] • Impacts of climate and land use change on the distribution of ticks were explored. • A model of different ticks showed diverse sensitivities to environmental factors. • The future distribution probability decreased under the scenario SSP5-RCP8.5. • The future potential distribution of ticks shifted further north in China. Ticks are known as vectors of several pathogens causing various human and animal diseases including Lyme borreliosis, tick-borne encephalitis, and Crimean-Congo hemorrhagic fever. While China is known to have more than 100 tick species well distributed over the country, our knowledge on the likely distribution of ticks in the future remains very limited, which hinders the prevention and control of the risk of tick-borne diseases. In this study, we selected four representative tick species which have different regional distribution foci in mainland China. i.e., Dermacentor marginatus , Dermacentor silvarum , Haemaphysalis longicornis and Ixodes granulatus. We used the MaxEnt model to identify the key environmental factors of tick occurrence and map their potential distributions in 2050 under four combined climate and socioeconomic scenarios (i.e., SSP1-RCP2.6, SSP2-RCP4.5, SSP3-RCP7.0 and SSP5-RCP8.5). We found that the extent of the urban fabric, cropland and forest, temperature annual range and precipitation of the driest month were the main determinants of the potential distributions of the four tick species. Under the combined scenarios, with climate warming, the potential distributions of ticks shifted to further north in China. Due to a decrease in the extent of forest, the distribution probability of ticks declined in central and southern China. In contrast with previous findings on an estimated amplification of tick distribution probability under the extreme emission scenario (RCP8.5), our studies projected an overall reduction in the distribution probability under RCP8.5, owing to an expected effect of land use. Our results could provide new data to help identify the emerging risk areas, with amplifying suitability for tick occurrence, for the prevention and control of tick-borne zoonoses in mainland China. Future directions are suggested towards improved quantity and quality of the tick occurrence database, comprehensiveness of factors and integration of different modelling approaches, and capability to model pathogen spillover at the human-tick interface. [ABSTRACT FROM AUTHOR]

• Two models were used to predict the potential distribution of Ae. albopictus in China. • The future bioclimatic variables were under the SSP1–2.6. • The range of Ae. albopictus in China is predicted to expand westwards. Aedes albopictus (Skuse) (Diptera: Culicidae) is one of the 100 most invasive species in the world and represents a significant threat to public health. The distribution of Ae. albopictus has been expanding rapidly due to increased international trade, population movement, global warming and accelerated urbanization. Consequently, it is very important to know the potential distribution area of Ae. albopictus in advance for early warning and control of its spread and invasion. We randomly selected 282 distribution sites from 27 provincial-level administrative regions in China, and used the GARP and MaxEnt models to analyze and predict the current and future distribution areas of Ae. albopictus in China. The results showed that the current range of Ae. albopictus in China covers most provinces such as Yunnan and Guizhou Provinces, and the distribution of Ae. albopictus in border provinces such as Tibet, Gansu and Jilin Provinces tend to expand westwards. In addition, the potential distribution area of Ae. albopictus in China will continue to expand westwards due to future climate change under the SSP126 climate scenario. Furthermore, the results of environmental factor filtering showed that temperature and precipitation had a large effect on the distribution probability of Ae. albopictus. [Display omitted] [ABSTRACT FROM AUTHOR]

Ornithodoros ticks as vectors of pathogens have had serious implications on public health. In China, these ticks are mainly distributed among arid and semiarid areas of the northwest. To improve prevention and risk control of such tick-borne diseases, suitable habitats for four Ornithodoros tick species found in China were predicted using a Maxent model. These habitats were identified based on the global geographic distributions that the tick is known to inhabit. For this study, literature reviews were conducted for each Ornithodoros species at a global level based on published studies and available online databases. Study results showed that high species suitability was primarily concentrated in northwest China for the species Ornithodoros lahorensis , O. papillipes , and O. tartakovskyi , with O. capensis limited to a predicted distribution along the coast in southeastern China. Under future climate conditions Representative Concentration Pathway scenario 4.5 and 8.5, suitable habitats for O. lahorensis , O. papillipes , and O. tartakovskyi were predicted to shift and would likely increase the potential of the species to spread, and O. capensis would reduce compared with the current climatic conditions. For all four species, temperature and precipitation were the main variables influencing distribution. • Northwest China was high species suitability areas for Ornithodoros. • O. capensis limited to a predicted distribution along the coast in southeastern China. • Using atmospheric and ground-derived data to assess the environmental niche. [ABSTRACT FROM AUTHOR]

Eastern China was once listed as an area infested with the invasive codling moth Cydia pomonella L. ( Lepidoptera: Tortricide). Intensive efforts later revealed the absence of such infestation. Currently, the majority of the population is distributed in western China. A disjunct population is also observed in the north east., In present study, the disjunct distribution was interpreted by mapping the climate dimension and potential distribution using an ecological niche modelling approach. The preferred niche models were utilized to identify the relative roles of climate, human influence and vegetation with respect to the present distribution and also to extrapolate the climate dimensions suitable for the codling moth in China., The results of the present study suggest that a combination of climate suitability and human influence explain the range expansion. Undistributed areas in eastern China were found to have low to medium climate suitability. Nonetheless, these areas belong to apple-growing regions that have high propagule pressure; thus, eventual establishment appears to be possible because of host plant availability, human activity and the wide ecological flexibility of the moth., Highly suitable habitats were found to be strongly related to high temperature and low precipitation throughout the year, whereas areas with low temperature and plenty of rainfall are unfavourable. [ABSTRACT FROM AUTHOR]