scholarly journals Distribution and establishment of the alien Australian redclaw crayfish,Cherax quadricarinatus, in South Africa and Swaziland

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3135 ◽  
Author(s):  
Ana L. Nunes ◽  
Tsungai A. Zengeya ◽  
Andries C. Hoffman ◽  
G. John Measey ◽  
Olaf L.F. Weyl
Keyword(s):  
South Africa ◽  
Control Measures ◽  
Current Status ◽  
Spread Rate ◽  
Cherax Quadricarinatus ◽  
Juvenile Dispersal ◽  
Rate Of Spread ◽  
Freshwater Biota ◽  
Aquaculture Facilities ◽  
Redclaw Crayfish

BackgroundThe Australian redclaw crayfish (Cherax quadricarinatus, von Martens), is native to Australasia, but has been widely translocated around the world due to aquaculture and aquarium trade. Mostly as a result of escape from aquaculture facilities, this species has established extralimital populations in Australia and alien populations in Europe, Asia, Central America and Africa. In South Africa,C. quadricarinatuswas first sampled from the wild in 2002 in the Komati River, following its escape from an aquaculture facility in Swaziland, but data on the current status of its populations are not available.MethodsTo establish a better understanding of its distribution, rate of spread and population status, we surveyed a total of 46 sites in various river systems in South Africa and Swaziland. Surveys were performed between September 2015 and August 2016 and involved visual observations and the use of collapsible crayfish traps.ResultsCherax quadricarinatusis now present in the Komati, Lomati, Mbuluzi, Mlawula and Usutu rivers, and it was also detected in several off-channel irrigation impoundments. Where present, it was generally abundant, with populations having multiple size cohorts and containing ovigerous females. In the Komati River, it has spread more than 112 km downstream of the initial introduction point and 33 km upstream of a tributary, resulting in a mean spread rate of 8 km year−1downstream and 4.7 km year−1upstream. In Swaziland, estimated downstream spread rate might reach 14.6 km year−1. Individuals were generally larger and heavier closer to the introduction site, which might be linked to juvenile dispersal.DiscussionThese findings demonstrate thatC. quadricarinatusis established in South Africa and Swaziland and that the species has spread, not only within the river where it was first introduced, but also between rivers. Considering the strong impacts that alien crayfish usually have on invaded ecosystems, assessments of its potential impacts on native freshwater biota and an evaluation of possible control measures are, therefore, urgent requirements.

scholarly journals First record of the invasive Australian redclaw crayfish Cherax quadricarinatus (von Martens, 1868) in the Crocodile River, Kruger National Park, South Africa

Koedoe ◽  
2017 ◽  
Vol 59 (1) ◽  
Author(s):  
Robin M. Petersen ◽  
Andries C. Hoffman ◽  
Pieter Kotze ◽  
Sean M. Marr
Keyword(s):  
Aquatic Ecosystems ◽  
National Park ◽  
Habitat Preferences ◽  
Kruger National Park ◽  
Mitigation Strategies ◽  
Freshwater Crayfish ◽  
Cherax Quadricarinatus ◽  
Rate Of Spread ◽  
Invasive Crayfish ◽  
Redclaw Crayfish

The redclaw crayfish Cherax quadricarinatus (von Martens, 1868), a robust freshwater crayfish native to Australia and Papua New Guinea, has now been recorded from the Kruger National Park (KNP). Previously absent from the Crocodile River, SAN Parks received a report in February 2016 of redclaw crayfish below the Van Graan Dam on the border of the KNP. Here, we provide evidence of the presence of redclaw crayfish in the Crocodile River. A better understanding of the redclaw crayfish distribution, habitat preferences, rate of spread and impacts on the local aquatic ecosystems in the Crocodile River is urgently required to develop mitigation strategies that minimise the spread of this invasive crayfish in the KNP and the Komati Catchment. The negative impacts of global crayfish introductions justify efforts to discourage further introductions and prevent their secondary spread.Conservation implications: A better understanding of the redclaw crayfish distribution, habitat preferences, rate of spread and impacts on the local aquatic ecosystems in the Crocodile River is urgently required to develop mitigation strategies that minimise the spread of this invasive crayfish in the Kruger National Park and the Komati Catchment.

Current Status of Knowledge and Awareness of Diabetes Mellitus in Saudi Arabia

2020 ◽  
Vol 16 ◽  
Author(s):  
Asirvatham Alwin Robert ◽  
Ahmad Dakeel Al Awad ◽  
Mohamed Abdulaziz Al Dawish
Keyword(s):  
Diabetes Mellitus ◽  
Saudi Arabia ◽  
Disease Risk ◽  
Current Knowledge ◽  
Adult Population ◽  
Management Training ◽  
Control Measures ◽  
Current Status ◽  
Treatment Modalities ◽  
The Government

Abstract: Diabetes mellitus (DM) is a chronic disease, and the complications may be life-threatening; however, with proper treatment and control measures, it can be very well-managed. Self-management training and education of diabetes are critical in diabetes care and management. It is essential that patients with diabetes must have a comprehensive understanding of the nature of the disease, risk factors, complications, and possible treatment modalities to attenuate the complications. Over the last few years, DM in Saudi Arabia has been rapidly growing at an alarming rate. It has affected around one-fifth of the adult population, and by 2030, the numbers are predicted to rise further and exceed more than double the present number. An estimated tenfold increase has been reported over the past three decades in Saudi Arabia. However, there has not been much research focusing on understanding the knowledge and awareness of DM in Saudi Arabia as compared to developed nations. This review aims to present an overview of the current knowledge and awareness level of DM among the population of Saudi Arabia through an extensive review of the currently available literature. The review findings could be of immense assistance to the government, healthcare systems, educational institutions, and researchers to develop evidence-based programs, policies, and guidelines towards increasing the knowledge and awareness about diabetes and its management, so that early detection and management can be ensured to control the escalating burden of diabetes, in Saudi Arabia.

Current status and intervention of South Africa chicken production – A review

2021 ◽  
pp. 1-19
Author(s):  
P. Ayodeji Idowu ◽  
Oliver Zishiri ◽  
K. Agree Nephawe ◽  
Bohani Mtileni
Keyword(s):  
South Africa ◽  
Current Status

On the Correlation of Analytical and Experimental Free Shear Layer Similarity Profiles by Spread Rate Parameters

1971 ◽  
Vol 93 (3) ◽  
pp. 377-382 ◽  
Author(s):  
H. H. Korst ◽  
W. L. Chow
Keyword(s):  
Similarity Solutions ◽  
Free Shear Layer ◽  
Spread Rate ◽  
Empirical Parameter ◽  
Jet Mixing ◽  
Free Jet ◽  
Rate Of Spread ◽  
Profile Matching ◽  
Entire Flow ◽  
Definition Of

Analysis of turbulent isobaric free jet mixing normally requires the introduction of suitably formulated viscosity models. Similarity solutions can then be established which contain one empirical parameter. Such a parameter, however, not only describes the rate of spread of the mixing region, but also determines in detail the structure of the entire flow field. It is pointed out that this “spread rate parameter” σ depends on the selected viscosity model, the method of theoretical analysis, and the definition of profile matching. A comparison of different theoretical profiles can only be accomplished after these factors are properly recognized. Any attempts to contribute to the rather incomplete knowledge of the spread parameter must be cognizant of its dependence on the theoretical mixing model employed. This paper also establishes theoretical relations which allow comparison and consolidation of information based on different analytical concepts.

scholarly journals Leishmaniasis: Current Status of Vaccine Development

2001 ◽  
Vol 14 (2) ◽  
pp. 229-243 ◽  
Author(s):  
Emanuela Handman
Keyword(s):  
Dna Sequences ◽  
Vaccine Development ◽  
Development Program ◽  
Skin Lesions ◽  
Mononuclear Phagocytes ◽  
Control Measures ◽  
Host Susceptibility ◽  
Current Status ◽  
Dna Encoding ◽  
And Control

SUMMARY Leishmaniae are obligatory intracellular protozoa in mononuclear phagocytes. They cause a spectrum of diseases, ranging in severity from spontaneously healing skin lesions to fatal visceral disease. Worldwide, there are 2 million new cases each year and 1/10 of the world's population is at risk of infection. To date, there are no vaccines against leishmaniasis and control measures rely on chemotherapy to alleviate disease and on vector control to reduce transmission. However, a major vaccine development program aimed initially at cutaneous leishmaniasis is under way. Studies in animal models and humans are evaluating the potential of genetically modified live attenuated vaccines, as well as a variety of recombinant antigens or the DNA encoding them. The program also focuses on new adjuvants, including cytokines, and delivery systems to target the T helper type 1 immune responses required for the elimination of this intracellular organism. The availability, in the near future, of the DNA sequences of the human and Leishmania genomes will extend the vaccine program. New vaccine candidates such as parasite virulence factors will be identified. Host susceptibility genes will be mapped to allow the vaccine to be targeted to the population most in need of protection.

Lantana camara (lantana).

2021 ◽  
Author(s):  
Sarah E. Thomas ◽  
Julissa Rojas-Sandoval ◽  
Pedro Acevedo-Rodríguez
Keyword(s):  
South Africa ◽  
Biological Control ◽  
Control Measures ◽  
Economic Losses ◽  
Pests And Diseases ◽  
Control Programmes ◽  
Agricultural Weed ◽  
Successful Control ◽  
The Tropics ◽  
Ornamental Shrub

Abstract L. camara is a highly variable ornamental shrub, native of the neotropics. It has been introduced to most of the tropics and subtropics as a hedge plant and has since been reported as extremely weedy and invasive in many countries. It is generally deleterious to biodiversity and has been reported as an agricultural weed resulting in large economic losses in a number of countries. In addition to this, it increases the risk of fire, is poisonous to livestock and is a host for numerous pests and diseases. L. camara is difficult to control. In Australia, India and South Africa aggressive measures to eradicate L. camara over the last two centuries have been largely unsuccessful, and the invasion trajectory has continued upwards despite control measures. This species has been the target of biological control programmes for over a century, with successful control only being reported in a few instances.

scholarly journals Narrative review of EHDI in South Africa

2015 ◽  
Vol 62 (1) ◽  
Author(s):  
Selvarani Moodley ◽  
Claudine Storbeck
Keyword(s):  
South Africa ◽  
Hearing Loss ◽  
Hearing Screening ◽  
Narrative Review ◽  
Current Status ◽  
Western Cape ◽  
Comprehensive Overview ◽  
National Priority ◽  
Newborn Hearing ◽  
Made In

Background: With 17 babies born with hearing loss every day in South Africa, there is a pressing need for systematic Early Hearing Detection and Intervention (EHDI) services. Progress is being made in offering newborn hearing screening and studies have been conducted to document these processes within South Africa. However, due to the lack of a national and holistic overview of EHDI services to date, an accurate picture of the current status of EHDI within the South African context is required. Objective: To document and profile what has been published within the field of EHDI in South Africa over the last two decades (Jan 1995–Sept 2014) in order to gain a comprehensive overview of the current status and practice of screening and diagnosis in the field of paediatric hearing loss. Method: A narrative review of peer-reviewed articles related to EHDI in South Africa was conducted by searching the EBSCOHOST, SCOPUS and JSTOR databases for the period January 1995 to September 2014. Results: Results indicate that over the last two decades research and publications in the field of EHDI have increased considerably. These publications have revealed extensive knowledge related to paediatric hearing screening and intervention services in South Africa; however, this knowledge seems to be limited primarily to the provinces of Gauteng and the Western Cape. Furthermore, studies pertaining to diagnosis have revealed that, although much has been written on the scientific aspects on tools for diagnosis of hearing loss, there is a lack of comprehensive information on diagnostic protocols and procedures. Conclusion: Despite the clear progress being made in South Africa in the field of early hearing detection and intervention, there is a need for comprehensive studies on protocols and procedures in diagnosing paediatric hearing loss. Finally, the narrative review revealed a clear need to ensure that development and growth in the field of EHDI is a national priority and extends beyond the two provinces currently showing growth.

The Invasive Vespidae in South Africa: Potential Management Strategies and Current Status

2018 ◽  
Vol 26 (2) ◽  
pp. 267-285 ◽  
Author(s):  
C. van Zyl ◽  
P. Addison ◽  
R. Veldtman
Keyword(s):  
South Africa ◽  
Management Strategies ◽  
Current Status
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