Invasive species: the threat to human health

The damage that invasive species can cause to the environment and the economy are well known, but impacts on human health have been much less analysed. However, invasive species can cause impacts ranging from psychological effects, phobias, discomfort and nuisance to allergies, poisoning, bites, disease and even death. Invasives experts Giuseppe Mazza and Elena Tricarico of the University of Florence, Italy say that in addition to these direct effects, some work in more indirect ways. Humans are menaced by alien invasive species affecting the services provided by ecosystems. “These services are vital to our well-being: changes may decrease the availability of drinking water and of products from fisheries, agriculture and forestry, alter pollination and impoverish culture and recreation,” say Mazza and Tricarico.

Miluz
The invasive red swamp crayfish, linked to disease in fishermen (photo by Miluz).

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One Health: free online course from FutureLearn features CABI authors

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One Health is about connectedness: "the collaborative efforts of multiple disciplines working locally, nationally, and globally to attain optimal health for people, animals, plants and our environment”.

On One Health Day, November 3rd 2016, CABI's editors held a One Health (#OneHealth) Blogathon to focus attention, contributing a total of 6 blogs to Handpicked… and Carefully Sorted, each written from the viewpoint of a different sector.   Our Plantwise Blog contributed One Health: Plantwise’s ambition to improve the health of people, plants and animals.

We hope you found them informative but your learning need not be confined to our blogs!

Sign up to a free online One Health course from FutureLearn: starts November 7th 2016, runs for 6 weeks. Lecturers are the CABI authors Esther Schelling,  Jakob Zinsstag and Bassirou Bonfoh of Swiss Tropical & Public Health Institute.

Esther, Jakob  and Bassirou are all authors of chapters in CABI’s  book One Health: The Theory and Practice of Integrated Health Approaches [2015].  Indeed Esther and Jakob are also co-editors.

FutureLearn  courses are easy to follow and well-paced: you get one unit per week.  I speak from experience as because of my interest in evidence-based medicine, in October 2015, I took "Informed Health Consumer: Making Sense of Evidence". 

I hope you can make use of this One Health course.

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Prove it! Evidence based health blogs.

One Health working will improve health and well-being of us all: plant, animal, human and ecosystem!

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    Pastoralists, Mongolia. Image courtesy of Esther Schelling, Swiss TPH.

 One of a series of blogs written by CABI editors for One Health Day on November 3rd 2016
 
It's always nice to meet up with a CABI author at a conference especially when they are giving a talk around a theme dear to CABI‘s heart,  namely “One Health”: the concept of working across the interface of animal, plant, human  and environment  to achieve health  & development  which is sustainable and fair. CABI has been gathering, managing and generating research information across all these sectors since 1912.  We know “its all connected”.

The conference was the RSTMH biennial meeting [Cambridge UK, Sept 12-16th, 2016], and the author in question, Esther Schelling, co-editor  of CABI’s  book One Health: The Theory and Practice of Integrated Health Approaches [2015].    To read a  free e-chapter, use this link.

In One Health beyond early detection and control of zoonoses Esther talked about her long-time project with nomadic pastoralists in Chad and a rift valley fever (RVF) control project in Kenya.  She drew attention to the need for:

  • more interdisciplinary studies to include an evaluation of One Health working
  • involvement of social scientists
  • engagement of key stakeholders

And tellingly she provided a cost-benefit analysis to society of controlling zoonoses when the disease is in its animal host before it infects human beings. 

Those cost-benefit analyses made a deep impression on the delegates, many of whom were involved in zoonotic neglected tropical diseases. Perhaps for the first time they were appreciating the added benefits and synergies that a transdisciplinary approach between science, society, humanities and medicine could bring.

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Can We Strike Back Against Dengue?

Dengue is a mosquito-borne viral infection causing a severe flu-like illness and, sometimes causing a potentially lethal complication called severe dengue. The incidence of dengue has increased 30-fold over the last 50 years. The latest estimates suggest that up to 400 million infections occur annually in over 100 endemic countries, putting half of the world’s population at risk. Dengue flourishes in urban poor areas, suburbs and the countryside but also affects more affluent neighbourhoods in tropical and subtropical countries. But can dengue be brought under control?

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Image courtesy of ProjectManhattan

“Mosquito control, the only option available for dengue control, has failed,” says Duane Gubler, Professor and Founding Director of the Signature Research Program in Emerging Infectious Diseases at the Duke-NUS Graduate Medical School, Singapore. in a CAB Reviews Mini Review. However, he says new and innovative tools in the pipeline may provide the opportunity to rollback this disease.

The release of sterile male mosquitos, or mosquitoes infected with a common bacteria, Wolbachia, have the potential to limit the spread of infection, and field trials of both have been encouraging. There are new insecticides and antiviral drugs in the pipeline, and six vaccines are in clinical trials, three of which may be licensed by 2018-2019.The full text of the mini review “Is it time to rollback dengue?CAB Reviews 2014 9, 029, can be accessed free of charge by clicking on the title.

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Duane Gubler is one of the editors of “Dengue and Dengue Hemorrhagic Fever”, newly published by CABI. This 29-chapter book brings together leading research and clinical scientists to review dengue virus biology, epidemiology, entomology, therapeutics, vaccinology and clinical management. For more details about the book, go to: http://www.cabi.org/bookshop/book/9781845939649

Mystery disease in Ethiopia solved: linked to weed toxin

Imagine this…

A mysterious disease terrorising your community, not infectious but spreading nonetheless, and killing your relatives and neighbours. All you want to do is pack your bags and flee. Worse, when your plight comes to the attention of the health authorities, they are stumped and its not going to be easy or quick to solve.

A recent example of this kind of illness is “nodding disease (South Sudan, Uganda, and Tanzania), which affects children 5-15 years old: they suffer epileptic seizures which causes their heads to nod, and they end up severely disabled and finally die. The USA’s Centre for Disease Control (CDC) is working to identify the cause: so far, the best guess is that it’s linked to the parasite that causes river blindness combined with an autoimmune reaction, and exposure to chemicals could predispose.

Other examples of non-communicable disease outbreaks

On Global Health, I found there are outbreaks going back to 1911 (epidemic dropsy) but more recent ones were in India,  Bangladesh, Nigeria, Brazil, China, Afghanistan and even the USA.

 What are the likely causes for these outbreaks? The body of research, as found on databases like Global Health, tells us that they could be contamination of food and water supply, exposure to chemicals or heavy metals in the environment, or even use of traditional medicine.

 Mystery liver disease in Ethiopia with a ‘happy’ ending

Can public health authorities in low-income countries solve & stop such outbreaks?   Yes. In 2005, in Ethiopia, a 4 year long outbreak of liver disease in Tseda Emba, a small village of the Tahtay Koraro district of Tigray, finally reached the attention of the Tigray Health Bureau (THB). Now, in 2012, the multidisciplinary and one-health approach they initiated has “solved” the mysterious illness, significantly reducing new cases. 

 The research work was the subject of an entire session at the recent World Congress Public Health (WCPH-2012) in Ethiopia, and is now published as 5 papers in the supplement to April 2012’s edition of Ethiopian Medical Journal (EMJ). [Abstracts to these papers will be available on Global Health]. It demonstrates the relevance of the one-health approach to public health in low-income countries and is a fascinating detective story….

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Biofuels: a public health hazard?

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Jatropha curcas, image courtesy of Biofuels Information Exchange

It has come to my attention that Jatropha curcas (physic nut or purging nut) is being pushed in India as a biofuel crop (for oil) and that there is now an emerging public health problem there due to accidental poisoning of children.

An Indian member of the listserv HIFA2015 to which I belong, Pankaj Oudhia, reported increased hospitalisations of children across the nation during the Jatropha fruiting season in 2010. The seeds are tasty but it only takes 3 or 4 seeds and you end up in hospital.  Five children died. Cultivated in fields as the biofuel crop, he also reported it was deliberately planted in schools. 

Here at CABI, our scientists, projects and information specialists have much to offer on the topic of biofuels and in 2008 we launched the Biofuels Information Exchange. So I went straight there to see if they had discussed Jatropha in their Forum, which they had (see “Is jatropha really the 'miracle' biofuel crop that some profess it to be?” from Carole Ellison).

AS a biofuel crop its in its infancy and has many downsides, not least on food security & the fact that you can’t use the husks for feed.  One of the reasons it was even considered was that as a weed (originating in South America) it was thought likely to be easy & cheap to cultivate. Turns out to make it productive you do have to go heavy on the fertiliser (expensive) and it also can harbour a mosaic virus. Only in passing was it pointed out that the seeds were poisonous and then only with reference to its use for animal feed.

One of the issues raised in this HIFA2015 communication was the lack of knowledge in the local communities about the poisonous nature of the seeds, so that parents could not forewarn their children.  And obviously the authorities had no idea otherwise they’d not have planted them in schools!

Definitely a lack of communication between botanists, agriculturalists, governments and medics when it comes to people’s health.

Let’s not get complacent here in Europe. WE all need reminding which plants are poisonous or irritating in gardens and in the hedgerows. Then we should tell children not to eat or touch them. Just because a bird is eating a juicy red berry does not make it edible for humans or even your pet dog.

Knowing a traditional name helps even us….deadly nightshade is a dead give-away isn’t it?

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