scholarly journals Nairobi Sheep Disease Virus: a historical and epidemiological perspective

2020 ◽  
Author(s):  
Stephanie Krasteva ◽  
Manuel Jara ◽  
Alba Frias-De-Diego ◽  
Gustavo Machado

AbstractNairobi Sheep Disease virus (NSDv) is a zoonotic and tick-borne disease that can cause over 90% mortality in small ruminants. NSDv has historically circulated in East Africa and has recently emerged in the Asian continent. Despite efforts to control the disease, some regions, mostly in warmer climates, persistently report disease outbreaks. Consequently, it is necessary to understand how environmental tolerances and factors that influence transmission may shed light on its possible emergence in other regions. In this study, we quantified the available literature of NSDv from which occurrence data was extracted. In total, 308 locations from Uganda, Kenya, Tanzania, Somalia, India, Sri Lanka and China were coupled with landscape conditions to reconstruct the ecological conditions for NSDv circulation and identify areas of potential disease transmission risk. Our results identified areas suitable for NSDv in Ethiopia, Malawi, Zimbabwe, Southeastern China, Taiwan, and Vietnam. Unsuitable areas included Democratic Republic of Congo, Zambia, and Southern Somalia. In summary, soil moisture, livestock density, and precipitation predispose certain areas to NSDv circulation. It is critical to investigate the epidemiology of NSDv in order to promote better allocation of resources to control its spread in regions that are more at risk. This will help reduce disease impact worldwide as climate change will favor emergence of such vector-borne diseases in areas with dense small ruminant populations.

2019 ◽  
Vol 26 (16) ◽  
pp. 2974-2986 ◽  
Author(s):  
Kwang-sun Kim

Vectors are living organisms that transmit infectious diseases from an infected animal to humans or another animal. Biological vectors such as mosquitoes, ticks, and sand flies carry pathogens that multiply within their bodies prior to delivery to a new host. The increased prevalence of Vector-Borne Diseases (VBDs) such as Aedes-borne dengue, Chikungunya (CHIKV), Zika (ZIKV), malaria, Tick-Borne Disease (TBD), and scrub typhus has a huge impact on the health of both humans and livestock worldwide. In particular, zoonotic diseases transmitted by mosquitoes and ticks place a considerable burden on public health. Vaccines, drugs, and vector control methods have been developed to prevent and treat VBDs and have prevented millions of deaths. However, development of such strategies is falling behind the rapid emergence of VBDs. Therefore, a comprehensive approach to fighting VBDs must be considered immediately. In this review, I focus on the challenges posed by emerging outbreaks of VBDs and discuss available drugs and vaccines designed to overcome this burden. Research into promising drugs needs to be upgraded and fast-tracked, and novel drugs or vaccines being tested in in vitro and in vivo models need to be moved into human clinical trials. Active preventive tactics, as well as new and upgraded diagnostics, surveillance, treatments, and vaccination strategies, need to be monitored constantly if we are to manage VBDs of medical importance.


Author(s):  
Leila Khouaja ◽  
Slimane Ben Miled ◽  
Hassan Hbid

Epidemiology had an important development these last years allowing the resolution of a large number of problems and had good prediction on disease evolution. However, the transmission of several vector-borne diseases is closely connected to environmental protagonists, specially in the parasite-host interaction. Moreover, understanding the disease transmission is related to studying the ecology of all protagonists. These two levels of complexity(epidemiology and ecology) cannot be separated and have to be studied as a whole in a systematic way. Our goal is to understand the interaction of climate change on the evolution of a disease when the vector has ecological niche that depends on physiological state of development. We are particularly interested in tick vector diseases which are serious health problem affecting humans as well as domestic animals in many parts of the world. These infections are transmitted through a bite of an infected tick, and it appears that most of these infections are widely present in some wildlife species. L'épidémiologie a connu un développement important ces dernières années. Cette discipline a permis une meilleure compréhension del'évolution de maladies. Cependant, plusieurs maladies à transmission vectorielle sont étroitement liées aux protagonistes environnementaux. Ce constat est particulièrement vrai dans le contexte des interactions du parasite avec son hôte. De plus, comprendre la transmission de maladie est lié à l'étude de l'écologie de tous les protagonistes. Notre objectif est de comprendre l'influence du changement climatique sur l'évolution des maladies lorsque la niche écologique du vecteur dépend de l'état de développement physiologique de son hôte. Nous sommes particulièrement intéressés par les maladies vectorielles à tiques qui constituent un grave problème de santé touchant l'être humain et les animaux domestiques dans de nombreuses régions du monde. Ces infections sont généralement transmises par la piqûre d'une tique infectée et il apparaît que la plupart de ces infections sont largement présentées dans certaines espèces fauniques


2015 ◽  
Vol 101 (2) ◽  
pp. 188-191
Author(s):  
E Stachow

AbstractMedical Officers (MOs) and Medical Branch Ratings (MBRs) must maintain an awareness of the risk of vector-borne diseases among deployed personnel.Personnel working in the maritime environment may not expect to be at risk of tick bites, as ticks typically occupy habitats with dense vegetation such as forests or scrub land. However, tick-borne pathogens can cause serious and sometimes fatal disease, and therefore the risk of tick bites and associated diseases should be recognised.We present a case of a tick bite in a member of a ship’s company eight days after leaving port. The tick was identified as a brown dog tick (Rhipicephalus sanguineus), a species known to thrive indoors. We describe several important tick-borne diseases which can be transmitted by R. sanguineus and explore best practice for tick removal and aftercare. Finally, we outline the appropriate management of suspected tick-borne disease in deployed personnel in the maritime environment.


Author(s):  
Maha Bouzid

Waterborne diseases are caused by a multitude of pathogens and associated with a significant burden in both developed and developing countries. While the assessment of the adverse impacts of climate change on human heath from infectious diseases has mainly focused on vector-borne diseases, waterborne diseases prevalence and transmission patterns are also likely to be impacted by environmental change. This chapter will outline relevant waterborne pathogens, summarise the impact of climate change on disease transmission and explore climate change adaptation options in order to reduce the increased burden of waterborne diseases.


2017 ◽  
pp. 1041-1055
Author(s):  
Maha Bouzid

Waterborne diseases are caused by a multitude of pathogens and associated with a significant burden in both developed and developing countries. While the assessment of the adverse impacts of climate change on human heath from infectious diseases has mainly focused on vector-borne diseases, waterborne diseases prevalence and transmission patterns are also likely to be impacted by environmental change. This chapter will outline relevant waterborne pathogens, summarise the impact of climate change on disease transmission and explore climate change adaptation options in order to reduce the increased burden of waterborne diseases.


2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Meredith R. Spence Beaulieu ◽  
Jennifer L. Federico ◽  
Michael H. Reiskind

Abstract Background Urbanization is occurring rapidly on a global scale and is altering mosquito communities, creating assemblages that are characteristically less diverse. Despite high rates of urbanization and ample examples of vector-borne diseases transmitted by multiple species, the effects of urbanization-driven mosquito diversity losses on disease transmission has not been well explored. We investigated this question using the dog heartworm, a filarial parasite vectored by numerous mosquito species. Methods We trapped host-seeking mosquitoes in undeveloped areas and neighborhoods of different ages in Wake County, North Carolina, USA, analyzing captured mosquitoes for heartworm DNA. We compared within-mosquito heartworm infection across land-use types by Kruskal–Wallis and likelihood ratio tests. Using zip code level data acquired from dogs in a local shelter, we performed linear regressions of within-host heartworm prevalence by within-mosquito heartworm prevalence as well as by three mosquito diversity measures. We also determined the best predictor of host-level prevalence among models including within-mosquito infection, mosquito diversity and abundance, and socioeconomic status as variables. Results Suburban areas had lower within-mosquito heartworm prevalence and lower likelihood of heartworm-positive mosquitoes than did undeveloped field sites, although no differences were seen between suburban and undeveloped wooded sites. No relationships were noted between within-mosquito and within-host heartworm prevalence. However, mosquito diversity metrics were positively correlated with host heartworm prevalence. Model selection revealed within-host prevalence was best predicted by a positive relationship with mosquito Shannon–Wiener diversity and a negative relationship with household income. Conclusions Our results demonstrate that decreases in mosquito diversity due to urbanization alter vector-borne disease risk. With regard to dog heartworm disease, this loss of mosquito diversity is associated with decreased heartworm prevalence within both the vector and the host. Although the response is likely different for diseases transmitted by one or few species, mosquito diversity losses leading to decreased transmission could be generalizable to other pathogens with multiple vectors. This study contributes to better understanding of the effects of urbanization and the role of vector diversity in multi-vectored pathosystems.


2018 ◽  
Vol 8 (4) ◽  
pp. 745-747
Author(s):  
Sruthi James ◽  
Brijesh Sathian ◽  
Edwin Van Teijlingen ◽  
Mohammad Asim

In South Asia, the monsoon brings life to vegetation, but at the same time has potential to cause public health problems. Notably, the climate change due to global warming is affecting the extent of monsoon rainfall in the region causing flooding which increases the risks of major disease outbreaks.  Flooding and standing water after heavy rainfall increases the risk of vector-borne diseases such as dengue, malaria, plague, chikungunya, typhoid, cholera and Leptospirosis.  Worldwide, Leptospirosis is one of the most common and emerging zoonoses, except on the North and South Poles. Rat fever or leptospirosis is a bacterial infection caused by the spiral-shaped bacteria (spirochete) of the genus Leptospira. This infection is mainly seen in wild and even domesticated species of rodents. It is mainly transmitted to humans by exposure of the mucous membranes (oral, nasal & eye) and skin abrasions or cuts to the urine or tissues of infected rodents or soil contaminated by their urine. Rats are the primary reservoir of leptospirosis, although farm animals and livestock, such as horses, pigs, dogs or cattle, and even wild animals can also be a reservoir for the bacteria. However, human-to-human transmission seems to occur occasionally. It is also an occupational hazard with potential risk of exposure among outdoors workers such as farmers, cleaners, veterinarians, agricultural workers. Moreover, there exists an increased chance of a recreational hazard to those who swims and wades in contaminated waters .


2005 ◽  
Vol 143 (6) ◽  
pp. 463-468 ◽  
Author(s):  
O. A. E. SPARAGANO

Ticks are considered in Europe to be the most important arthropod group responsible for vector-borne diseases in humans, while in the tropics mosquitoes take over this position with ticks being the second most important. Over the last decade, vector-borne diseases have proliferated within Southern Europe (Blue tongue and West Nile viruses, both mosquito-borne diseases) while human ehrlichiosis (a tick-borne disease) has increased dramatically in Eastern Europe.


2015 ◽  
Vol 370 (1665) ◽  
pp. 20130551 ◽  
Author(s):  
Paul E. Parham ◽  
Joanna Waldock ◽  
George K. Christophides ◽  
Deborah Hemming ◽  
Folashade Agusto ◽  
...  

Arguably one of the most important effects of climate change is the potential impact on human health. While this is likely to take many forms, the implications for future transmission of vector-borne diseases (VBDs), given their ongoing contribution to global disease burden, are both extremely important and highly uncertain. In part, this is owing not only to data limitations and methodological challenges when integrating climate-driven VBD models and climate change projections, but also, perhaps most crucially, to the multitude of epidemiological, ecological and socio-economic factors that drive VBD transmission, and this complexity has generated considerable debate over the past 10–15 years. In this review, we seek to elucidate current knowledge around this topic, identify key themes and uncertainties, evaluate ongoing challenges and open research questions and, crucially, offer some solutions for the field. Although many of these challenges are ubiquitous across multiple VBDs, more specific issues also arise in different vector–pathogen systems.


2020 ◽  
Author(s):  
Katerina Kassela ◽  
Adamantia Kouvela ◽  
Michael de Courcy Williams ◽  
Konstantinos Konstantinidis ◽  
Maria Goreti Rosa Freitas ◽  
...  

AbstractIn the era of emergence and re-emergence of vector-borne diseases, a high throughput trap-based insect monitoring is essential for the identification of invasive species, study of mosquito populations and risk assessment of disease outbreaks. Insect DNA metabarcoding technology has emerged as a highly promising methodology for unbiased and large-scale surveillance. Despite significant attempts to introduce DNA metabarcoding in mosquito or other insect surveillance qualitative and quantitative metabarcoding remains a challenge. In the present study, we have developed a methodology of in-tandem identification and quantification using cytochrome oxidase subunit I (COI) combined with a secondary multilocus identification and quantification involving three loci of 28S ribosomal DNA. The presented methodology was able to identify individual species in pools of mosquitoes with 95.94% accuracy and resolve with high accuracy (p = 1, χ2 = 2.55) mosquito population composition providing a technology capable of revolutionizing mosquito surveillance through metabarcoding. The methodology, given the respective dataset, has the potential to be applied to various small animal populations.


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