Environmental and biotic factors affecting freshwater snail intermediate hosts in the Ethiopian Rift Valley region

Background: Knowledge of the distribution and habitat preference of freshwater snail intermediate hosts can provide information to initiate and set-up effective snail control programmes. However, there is limited research conducted on the factors driving the occurrence and abundance of freshwater snail intermediate hosts in the Ethiopian Rift Valley. Hence, in this study, we investigated how environmental and biotic factors influence the occurrence and abundance of the snail intermediate hosts in Ethiopian Rift Valley region. Methods: Data on freshwater snails, physico-chemical water quality parameters, physical characteristics of habitat, predators and competitors, and anthropogenic activity variables were collected from 174 sampling sites during the wet season of 2017 and 2018. Generalized linear models were used to identify the main environmental and biotic factors affecting the occurrence and abundance of the snail species. Results: It was found that Bulinus globosus (31.7%) was the most abundant snail species followed by Lymnaea natalensis (21.6%), Lymnaea truncatula (15.1%) and Biomphalaria pfeifferi (14.6%). Generalized linear models indicated that physico-chemical parameters (water temperature, turbidity, chlorophyll-a, dissolved oxygen, chemical oxygen demand, alkalinity, calcium, magnesium, nitrate and ammonia), physical habitat characteristics (water depth, canopy cover, macrophyte cover and substrate type) and biotic factors (abundance of predators and competitors) were found to be the main variables determining the occurrence and abundance of snail species in the Ethiopian Rift Valley region. In terms of anthropogenic activities, human settlement, farming, bathing and swimming, clothes washing, grazing, drainage of land, car washing, boating, fishing and silviculture were also important variables determining the occurrence and abundance of snail species in the region. Conclusions: The findings reported herein suggest that integrated snail control strategies should be considered to control snails via protection of water bodies from disturbance by anthropogenic activities. In this way, it is possible to reduce the concentration of organic matter and dissolved ions in aquatic ecosystems which are conducive for the presence of snails

Fascioliasis prevalence in livestock from abattoirs in southern Chile

Fascioliasis is a widely distributed parasitic zoonosis caused by the trematode Fasciola hepatica that affects livestock production and generates high economic losses. In Chilean authorised abattoirs, the infected livestock livers are condemned during the veterinary inspection. This study aims to evaluate the prevalence of fascioliasis in Chile from 2014 to 2016 and also monthly from 2002 to 2015 in livestock (cattle, pig, sheep, horse and goat) slaughtered in abattoirs of La Araucanía region, southern Chile. To do this, the available records on abattoirs provided by the sanitary authority were analysed. A descriptive statistics and trend analysis of the data by jointpoint regression was carried out. The Biobío and La Araucanía regions registered the highest levels of parasitosis in the country recording levels of 59.18 and 44.74%, respectively, and presented 50.03% of the liver condemnation rate in cattle. During the study period, a total of 2,239,164 animals were slaughtered and 40.59% infected livers with F. hepatica were condemned in the 9 existing abattoirs of La Araucanía region. The abattoirs located in the cities of Temuco (51.43%) and Angol (65.09%) recorded the highest percentages of fascioliasis. The cattle species recorded the highest number of slaughtered animals and liver condemnation (54.52%). The presence of the parasite was recorded annually and monthly and it was possible to observe a slight increase in fascioliasis over the years. This study provides updated information on the fascioliasis prevalence in the country and the dynamics of condemnation in endemic areas such as La Araucanía region, which could contribute to the control and prevention of this zoonosis

Potential hybridization of Fasciola hepatica and F. gigantica in Africa

SUPPLEMENTARY MATERIALS : TABLE S1: Summary of African studies reporting on the presence of Fasciola species recovered from various definitive hosts. TABLE S2: The distribution and occurrence of Fasciola species in Africa based on studies conducted from 1980–2022. TABLE S3: Summary of African studies reporting on the occurrence of Fasciola species in their snail intermediate hosts. TABLE S4: Summary of studies reporting on the occurrence of intermediate hosts of Fasciola spp. in Africa. References [140–317] are cited in the supplementary materials.The occurrence of Fasciola gigantica and F. hepatica in Africa is well documented; however, unlike in Asia, there is a paucity of information on the existence of hybrids or parthenogenetic species on the continent. Nonetheless, these hybrid species may have beneficial characteristics, such as increased host range and pathogenicity. This study provides evidence of the potential existence of Fasciola hybrids in Africa. A literature search of articles published between 1980 and 2022 was conducted in PubMed, Google Scholar, and Science Direct using a combination of search terms and Boolean operators. Fasciola species were documented in 26 African countries with F. hepatica being restricted to 12 countries, whilst F. gigantica occurred in 24 countries, identified based on morphological features of adult Fasciola specimens or eggs and molecular techniques. The cooccurrence of both species was reported in 11 countries. However, the occurrence of potential Fasciola hybrids was only confirmed in Egypt and Chad but is suspected in South Africa and Zimbabwe. These were identified based on liver fluke morphometrics, assessment of the sperms in the seminal vesicle, and molecular techniques. The occurrence of intermediate host snails Galba truncatula and Radix natalensis was reported in Ethiopia, Egypt, South Africa, Tanzania, and Uganda, where F. hepatica and F. gigantica co-occurrences were reported. The invasive Pseudosuccinea columella snails naturally infected with F. gigantica were documented in South Africa and Egypt. In Zimbabwe, P. columella was infected with a presumed parthenogenetic Fasciola. This suggests that the invasive species might also be contributing to the overlapping distributions of the two Fasciola species since it can transmit both species. Notwithstanding the limited studies in Africa, the potential existence of Fasciola hybrids in Africa is real and might mimic scenarios in Asia, where parthenogenetic Fasciola exist in most Asian countries. In South Africa, aspermic F. hepatica and Fasciola sp. have been reported already, and Fasciola hybrids have been reported? in Chad and Egypt. Thus, the authors recommend future surveys using molecular markers recommended to identify Fasciola spp. and their snail intermediate hosts to demarcate areas of overlapping distribution where Fasciola hybrids and/or parthenogenetic Fasciola may occur. Further studies should also be conducted to determine the presence and role of P. columella in the transmission of Fasciola spp. in these geographical overlaps to help prevent parasite spillbacks.The European Union’s Horizon 2020 research and innovation program, the National Research Foundation (NRF) of South Africa, the Knud Højgaards Foundation for its support to The Research Platform for Disease Ecology, Health and Climate.https://www.mdpi.com/journal/pathogensam2023Veterinary Tropical Disease

Late Quaternary palaeolimnology and environmental change in the South Wollo Highlands, Ethiopia

Lake Hayq is a closed, freshwater basin on the eastern margin of the north-central highlands, Ethiopia. Using a sediment core extracted from the northern basin, this thesis aims to provide a high-resolution, detailed palaeolimnological reconstruction of changes to the environment and climate in the region since the late Pleistocene. A multi-proxy approach was applied, utilising diatoms, photosynthetic pigments and X-ray fluorescence (XRF) spectrometry. Lithological and chronological analyses were also performed, as well as the development of a transfer function to model diatom-inferred conductivity, and other quantitative analyses. Between ~ 15.6 15.1 cal kyr BP, Lake Hayq experienced a lowstand, synchronous with the timing of Heinrich Event 1 and an intense drought across East Africa. At ~ 15.1 cal kyr BP a lake began to develop at the core site in response to wetter, more humid conditions, most likely caused by the reactivation of the African-Indian monsoonal circulation. This was abruptly ended however at ~ 14.7 cal kyr BP, as the climate shifted back towards aridity and Lake Hayq shallowed, in contrast to the majority of other East African lakes, which continued to refill. This most likely reflects changes to the Indian Ocean monsoon system caused by variability in the Atlantic Meridional Overturning Circulation at this time, in conjunction with site-specific mechanisms affecting the delivery of precipitation to Lake Hayq. At ~ 12.3 cal kyr BP the African Humid Period resumed over Lake Hayq and the lake refilled, reaching maximum water depth between ~ 12.0 10.0 cal kyr BP. The lake was dominated by planktonic diatom taxa and photosynthetic pigments indicate it was meromictic. Lake level gradually declined throughout the Holocene, culminating in the termination of the African Humid Period. A high-resolution study of the period tentatively suggests that climate flickering , in the form of oscillations between dominant diatom taxa, occurred in the build up to the major climatic shift. The termination spanned ~ 600 cal years between ~ 5.2 4.6 cal kyr BP. A lowstand occurred between ~ 3.9 2.2 cal kyr BP, during which the lake became occasionally subsaline. In the late Holocene, ~ 2.2 1.3 cal kyr BP, Lake Hayq became deep and fresh again, although there is evidence of lake level variability. The palaeo-record from Lake Hayq indicates that it broadly experienced the same high-latitude, glacial-interglacial dynamics and sub-millennial shifts in climate found in other palaeolimnological records from across East Africa. The precise timing and expression of these climatic events is not always synchronous between Lake Hayq and other East African waterbodies however, most likely caused by local, site-specific positive feedback mechanisms and variability in lake morphometry. This highlights the heterogeneous pattern of climate across the region and the significance of regional drivers. This palaeo-record, spanning the late Quaternary, will help bridge gaps in current knowledge and understanding of the underrepresented, climatically sensitive and vulnerable north Ethiopian highlands. This is vital for future climate change modelling and regional downscaling, and may also inform ethnographic-archaeological research in a region considered to be the cradle of humankind

Urbanization, Biodiversity and Ecosystem Services: Challenges and Opportunities

Urbanization is a global phenomenon and the book emphasizes that this is not just a social-technological process. It is also a social-ecological process where cities are places for nature, and where cities also are dependent on, and have impacts on, the biosphere at different scales from local to global. The book is a global assessment and delivers four main conclusions: Urban areas are expanding faster than urban populations. Half the increase in urban land across the world over the next 20 years will occur in Asia, with the most extensive change expected to take place in India and China Urban areas modify their local and regional climate through the urban heat island effect and by altering precipitation patterns, which together will have significant impacts on net primary production, ecosystem health, and biodiversity Urban expansion will heavily draw on natural resources, including water, on a global scale, and will often consume prime agricultural land, with knock-on effects on biodiversity and ecosystem services elsewhere Future urban expansion will often occur in areas where the capacity for formal governance is restricted, which will constrain the protection of biodiversity and management of ecosystem service

Urbanization, Biodiversity and Ecosystem Services: Challenges and Opportunities: A Global Assessment

Urban Ecology; Urbanism; Sustainable Development; Complex Systems; Science, general; International Environmental La

Saving Bones: a direct comparison of FTIR-ATR, whole bone percent nitrogen, and NIR

89th Annual Meeting of the American-Association-of-Physical-Anthropologists (AAPA), Los Angeles, CA, APR 15-18, 202