scholarly journals Global shifts in mammalian population trends reveal key predictors of virus spillover risk

2020 ◽  
Vol 287 (1924) ◽  
pp. 20192736 ◽  
Author(s):  
Christine K. Johnson ◽  
Peta L. Hitchens ◽  
Pranav S. Pandit ◽  
Julie Rushmore ◽  
Tierra Smiley Evans ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Close Contact ◽  
Anthropogenic Activities ◽  
Mammalian Species ◽  
Species Abundance ◽  
Zoonotic Disease ◽  
Wildlife Habitat ◽  
Transmission Risk ◽  
Population Declines ◽  
Zoonotic Viruses

Emerging infectious diseases in humans are frequently caused by pathogens originating from animal hosts, and zoonotic disease outbreaks present a major challenge to global health. To investigate drivers of virus spillover, we evaluated the number of viruses mammalian species have shared with humans. We discovered that the number of zoonotic viruses detected in mammalian species scales positively with global species abundance, suggesting that virus transmission risk has been highest from animal species that have increased in abundance and even expanded their range by adapting to human-dominated landscapes. Domesticated species, primates and bats were identified as having more zoonotic viruses than other species. Among threatened wildlife species, those with population reductions owing to exploitation and loss of habitat shared more viruses with humans. Exploitation of wildlife through hunting and trade facilitates close contact between wildlife and humans, and our findings provide further evidence that exploitation, as well as anthropogenic activities that have caused losses in wildlife habitat quality, have increased opportunities for animal–human interactions and facilitated zoonotic disease transmission. Our study provides new evidence for assessing spillover risk from mammalian species and highlights convergent processes whereby the causes of wildlife population declines have facilitated the transmission of animal viruses to humans.

Measuring interpersonal transmission of expiratory droplet nuclei in close proximity

2021 ◽  
pp. 1420326X2110296
Author(s):  
Linzhi Fu ◽  
Peter V. Nielsen ◽  
Yi Wang ◽  
Li Liu
Keyword(s):  
Disease Transmission ◽  
Short Range ◽  
Close Contact ◽  
Measurement Techniques ◽  
Transmission Risk ◽  
Interpersonal Distance ◽  
Airborne Transmission ◽  
Face To Face ◽  
Close Proximity ◽  
Droplet Nuclei

Increasing evidence supports the significant role of short-range airborne transmission of viruses when in close contact with a source patient. A full-scale ventilated room (Cleanliness: ISO 14644–1 Class 5) and two face-to-face standing breathing thermal manikins were used to simulate a source individual and a susceptible person. Monodisperse particle generation and measurement techniques were used to evaluate the effect of virus-laden droplet nuclei size on short-range airborne transmission risk. We analysed four particle sizes (1.0, 1.5, 2.5, and 5.0 µm) to simulate the transport of exhaled droplet nuclei within an interpersonal distance of 0.5 m. The results indicated that the size distribution of airborne droplet nuclei could significantly influence transmission, with the inhalation fraction decreasing with increasing droplet nuclei size. Additionally, results showed that proximity to the source manikin could influence transmission. Inhalation fraction decreased with increasing interpersonal distance, fitting well with the 1/ d rule of droplet nuclei concentration decay. Our findings improve the understanding of the mechanism of the disease transmission.

scholarly journals Disaster displacement and zoonotic disease dynamics: The impact of structural and chronic drivers in Sindh, Pakistan

2021 ◽  
Vol 1 (12) ◽  
pp. e0000068
Author(s):  
Dorien H. Braam ◽  
Rafiq Chandio ◽  
Freya L. Jephcott ◽  
Alex Tasker ◽  
James L. N. Wood
Keyword(s):  
Rural Communities ◽  
Disease Transmission ◽  
Disease Risk ◽  
Animal Health ◽  
Forced Migration ◽  
Zoonotic Disease ◽  
Transmission Risk ◽  
Disease Dynamics ◽  
Displaced Populations ◽  
The Impact

Projected increases in human and animal displacement driven by climate change, disasters and related environmental degradation will have significant implications to global health. Pathways for infectious disease transmission including zoonoses, diseases transmitted between animals and humans, are complex and non-linear. While forced migration is considered an important driver for the spread of zoonoses, actual disease dynamics remain under researched. This paper presents the findings of a case study investigating how disaster displacement affected zoonotic disease transmission risk following the 2010 ‘superfloods’ in Sindh province, Pakistan. We interviewed 30 key informants and 17 household members across 6 rural communities between March and November 2019, supported by observational studies and a review of secondary data. Results were analysed using the ecosocial theoretical framework. Buffalo, cattle and goats were often the only moveable asset, therefore livestock was an important consideration in determining displacement modality and destination location, and crowded locations were avoided to protect human and animal health. Meanwhile however, livestock was rarely included in the humanitarian response, resulting in communities and households fragmenting according to the availability of livestock provisions. We found that rather than a driver for disease, displacement acted as a process affecting community, household and individual zoonotic disease risk dynamics, based on available resources and social networks before, during and after displacement, rooted in the historical, political and socio-economic context. We conclude that in rural Sindh, disaster displaced populations’ risk of zoonoses is the result of changes in dynamics rooted in pre-existing structural and chronic inequalities, making people more or less vulnerable to disease through multiple interlinked pathways. Our findings have implications for policy makers and humanitarian responders assisting displaced populations dependent on livestock, with a call to integrate livestock support in humanitarian policies and responses for health, survival and recovery.

scholarly journals 205Zoonotic disease transmission risk in displaced populations

2021 ◽  
Vol 50 (Supplement_1) ◽  
Author(s):  
Gates Scholar Dorien Braam ◽  
Freya Jephcott ◽  
James Wood
Keyword(s):  
Risk Factors ◽  
Disease Transmission ◽  
Disease Risk ◽  
Forced Migration ◽  
Zoonotic Disease ◽  
Humanitarian Assistance ◽  
Transmission Risk ◽  
Case Study Methodology ◽  
Displaced Populations ◽  
Zoonotic Disease Transmission

Abstract Background Repeated spillover events of zoonotic diseases from animals to humans, in combination with unprecedented levels of forced migration, present a major challenge to the global health security agenda. Infectious disease risk is affected by a range of ecological, political and socio-economic drivers. Methods This study uses a qualitative case study methodology to determine how displacement affects the risks of zoonotic disease transmission. Based on key informant interviews and observational studies in Jordan and Pakistan, the study analyses social-structural factors impacting zoonotic disease transmission. Results The study shows that displacement may influence zoonotic disease transmission through its impact on environmental, socio-economic and behavioural factors, influenced by historical, political and socio-economic processes. Sporadic outbreaks of zoonoses including cutaneous leishmaniasis, rabies and Tuberculosis are reported among displaced populations. Risk factors include a decline in health services, increased population density, changes in environment, and reduced quality and availability of shelter, water and nutrition, in turn determining vulnerability to vectors and pathogens. Conclusions Risk factors affecting zoonoses in displacement are complex and interlinked. While the presence of animals may increase the risk in densely populated areas lacking hygiene, livestock may be beneficial to the health status of displaced by improving nutrition. Responses need to be interdisciplinary, multilevel and contextualized. Key messages To mitigate the risk of zoonotic disease transmission during displacement, responses need to include pathogen and vector control, as well as reducing vulnerability to disease, including through access to health and veterinary services and humanitarian assistance.

scholarly journals Livestock movement informs the risk of disease spread in traditional production systems in East Africa

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Divine Ekwem ◽  
Thomas A. Morrison ◽  
Richard Reeve ◽  
Jessica Enright ◽  
Joram Buza ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Production Systems ◽  
Control Strategies ◽  
Herd Size ◽  
Transmission Risk ◽  
Disease Spread ◽  
Transmission Potential ◽  
Spatial And Temporal Scales ◽  
Transmission Distance ◽  
Risk Of Disease

AbstractIn Africa, livestock are important to local and national economies, but their productivity is constrained by infectious diseases. Comprehensive information on livestock movements and contacts is required to devise appropriate disease control strategies; yet, understanding contact risk in systems where herds mix extensively, and where different pathogens can be transmitted at different spatial and temporal scales, remains a major challenge. We deployed Global Positioning System collars on cattle in 52 herds in a traditional agropastoral system in western Serengeti, Tanzania, to understand fine-scale movements and between-herd contacts, and to identify locations of greatest interaction between herds. We examined contact across spatiotemporal scales relevant to different disease transmission scenarios. Daily cattle movements increased with herd size and rainfall. Generally, contact between herds was greatest away from households, during periods with low rainfall and in locations close to dipping points. We demonstrate how movements and contacts affect the risk of disease spread. For example, transmission risk is relatively sensitive to the survival time of different pathogens in the environment, and less sensitive to transmission distance, at least over the range of the spatiotemporal definitions of contacts that we explored. We identify times and locations of greatest disease transmission potential and that could be targeted through tailored control strategies.

scholarly journals Feeding sites promoting wildlife-related tourism might highly expose the endangered Yunnan snub-nosed monkey (Rhinopithecus bieti) to parasite transmission

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Eve Afonso ◽  
Rong Fu ◽  
Amaël Dupaix ◽  
Anne-Claude Goydadin ◽  
ZhongHua Yu ◽  
...  
Keyword(s):  
Disease Transmission ◽  
High Throughput Sequencing ◽  
Animal Health ◽  
Buffer Zone ◽  
Transmission Risk ◽  
Parasite Transmission ◽  
Rhinopithecus Bieti ◽  
Domesticated Animals ◽  
Feeding Sites ◽  
In The Wild

AbstractAn increasing number of studies have found that the implementation of feeding sites for wildlife-related tourism can affect animal health, behaviour and reproduction. Feeding sites can favour high densities, home range overlap, greater sedentary behaviour and increased interspecific contacts, all of which might promote parasite transmission. In the Yunnan snub-nosed monkey (Rhinopithecus bieti), human interventions via provisioning monkeys at specific feeding sites have led to the sub-structuring of a group into genetically differentiated sub-groups. The fed subgroup is located near human hamlets and interacts with domesticated animals. Using high-throughput sequencing, we investigated Entamoeba species diversity in a local host assemblage strongly influenced by provisioning for wildlife-related tourism. We identified 13 Entamoeba species or lineages in faeces of Yunnan snub-nosed monkeys, humans and domesticated animals (including pigs, cattle, and domestic chicken). In Yunnan snub-nosed monkeys, Entamoeba prevalence and OTU richness were higher in the fed than in the wild subgroup. Entamoeba polecki was found in monkeys, pigs and humans, suggesting that this parasite might circulates between the wild and domestic components of this local social–ecological system. The highest proportion of faeces positive for Entamoeba in monkeys geographically coincided with the presence of livestock and humans. These elements suggest that feeding sites might indirectly play a role on parasite transmission in the Yunnan snub-nosed monkey. The implementation of such sites should carefully consider the risk of creating hotspots of disease transmission, which should be prevented by maintaining a buffer zone between monkeys and livestock/humans. Regular screenings for pathogens in fed subgroup are necessary to monitor transmission risk in order to balance the economic development of human communities dependent on wildlife-related tourism, and the conservation of the endangered Yunnan snub-nosed monkey.

Investigating Male Aedes aegypti (Diptera: Culicidae) Attraction to Different Oviposition Containers Using Various Configurations of the Sound Gravid Aedes Trap

2019 ◽  
Vol 57 (3) ◽  
pp. 957-961
Author(s):  
Kyran M Staunton ◽  
Barukh B Rohde ◽  
Michael Townsend ◽  
Jianyi Liu ◽  
Mark Desnoyer ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Zika Virus ◽  
Disease Transmission ◽  
Urban Landscape ◽  
Mosquito Control ◽  
Transmission Risk ◽  
Northern Australia ◽  
Control Programs ◽  
Male Dispersal ◽  
Olfactory Attractant

Abstract Aedes aegypti (Linnaeus), the primary vectors of the arboviruses dengue virus and Zika virus, continue to expand their global distributions. In efforts to better control such species, several mosquito control programs are investigating the efficacy of rearing and releasing millions of altered male Aedes throughout landscapes to reduce populations and disease transmission risk. Unfortunately, little is known about Ae. aegypti, especially male, dispersal behaviors within urban habitats. We deployed Sound-producing Gravid Aedes Traps (SGATs) in Cairns, northern Australia, to investigate male Ae. aegypti attraction to various oviposition container configurations. The traps were arranged to include: 1) water only, 2) organically infused water, 3) infused water and L3 larvae, 4) infused water and a human-scented lure, and lastly 5) no water or olfactory attractant (dry). Our data suggest that males were more attracted to SGATs representing active larval sites than potential larval sites, but were equally attracted to dry SGATs relative to those containing water and/or infusion. Additionally, we found that female Ae. aegypti were equally attracted to wet SGATs, with or without infusion, but not dry ones. These results suggest that male Ae. aegypti within northern Australia are more attracted to active larval sites and equally attracted to dry containers as wet or infused ones. Additionally, female Ae. aegypti are unlikely to enter dry containers. Such findings contribute to our understanding of potentially attractive features for local and released Ae. aegypti throughout the northern Australian urban landscape.

scholarly journals Revealing the Micro-scale Signature of Endemic Zoonotic Disease Transmission in an African Urban Setting

2016 ◽  
Vol 12 (4) ◽  
pp. e1005525 ◽  
Author(s):  
Hervé Bourhy ◽  
Emmanuel Nakouné ◽  
Matthew Hall ◽  
Pierre Nouvellet ◽  
Anthony Lepelletier ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Zoonotic Disease ◽  
Urban Setting ◽  
Micro Scale ◽  
Zoonotic Disease Transmission

scholarly journals Human-induced changes in habitat preference by capybaras (Hydrochoerus hydrochaeris) and their potential effect on zoonotic disease transmission

2020 ◽  
Author(s):  
Thiago C. Dias ◽  
Jared A. Stabach ◽  
Qiongyu Huang ◽  
Marcelo B. Labruna ◽  
Peter Leimgruber ◽  
...  
Keyword(s):  
Habitat Selection ◽  
Disease Transmission ◽  
Resource Selection ◽  
Spotted Fever ◽  
Space Use ◽  
Zoonotic Disease ◽  
Disease Spread ◽  
Selection Strategies ◽  
Hydrochoerus Hydrochaeris ◽  
Natural Landscapes

AbstractHuman activities are changing landscape structure and function globally, affecting wildlife space use, and ultimately increasing human-wildlife conflicts and zoonotic disease spread. Capybara (Hydrochoerus hydrochaeris) is a conflict species that has been implicated in the spread and amplification of the most lethal tick-borne disease in the world, the Brazilian spotted fever (BSF). Even though essential to understand the link between capybaras, ticks and the BSF, many knowledge gaps still exist regarding the effects of human disturbance in capybara space use. Here, we analyzed diurnal and nocturnal habitat selection strategies of capybaras across natural and human-modified landscapes using resource selection functions (RSF). Selection for forested habitats was high across human- modified landscapes, mainly during day- periods. Across natural landscapes, capybaras avoided forests during both day- and night periods. Water was consistently selected across both landscapes, during day- and nighttime. This variable was also the most important in predicting capybara habitat selection across natural landscapes. Capybaras showed slightly higher preferences for areas near grasses/shrubs across natural landscapes, and this variable was the most important in predicting capybara habitat selection across human-modified landscapes. Our results demonstrate human-driven variation in habitat selection strategies by capybaras. This behavioral adjustment across human-modified landscapes may be related to BSF epidemiology.

scholarly journals Brucellosis in camel and human: Seroprevalence and associated risk factors in Amibara district of Afar region, Ethiopia

2021 ◽  
Author(s):  
Fekadu Gutema ◽  
Prof Kebede Amenu ◽  
Adugna Chalchisa ◽  
Prof Gezahegn Mamo
Keyword(s):  
Risk Factors ◽  
Close Contact ◽  
Mammalian Species ◽  
Raw Milk ◽  
Cross Sectional Study ◽  
Public Health Importance ◽  
Cross Sectional ◽  
North East ◽  
Afar Region ◽  
Associated Risk Factors

Abstract Background: Brucellosis is an important neglected zoonotic disease caused by infection with bacteria of the genus Brucella affecting different mammalian species including man. A cross-sectional study was conducted to estimate the seroprevalence of brucellosis in camels and human and its associated risk factors in Amibara district of Afar region, North east Ethiopia from October 2019 to May 2020Result: A total of 250 camel and 120 human sera were serially tested using the Rose Bengal Plate Test (RBPT), and Complement Fixation Test (CFT). The overall seroprevalence of camel brucellosis in the current study was 7.6% (95% CI: 4.9-11.56) using RBPT and 3.2% (95% CI: 1.63-6.2) by combined RBPT and CFT. In Human twelve (10%) of the collected sera were positive by RBPT among which only four of them (3.33%) were positive by CFT. The risk factors analysis indicated that, age, body condition, number of parity and abortion history were significantly associated with brucella seropositivity in camel(P≤0.05). In human, occupation and non-protective handling of dystocia cases showed apparent association with brucella seropositivity.Conclusion: The results of the present study indicated that, brucellosis is a common health problem in camel and human in Amibara district of Afar region. The public health importance of this disease is associated with raw milk consumption and close contact with the animals having history of recent abortion. Therefore, controlling the risk factors, establishing brucella diagnostic service in human clinics and hospitals, continuous social training with feedback assessments and overall implementing of One Health approach framework to attain optimal health for people and domestic animals in area are recommended to safeguard the health of society.

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