Emerging Diseases


ILRI Clippings

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A woman sorts through a heap of garbage at the Dandora dumping site among other people, cattle, pigs and storks, in Nairobi (photo credit: Simon Maina / AFP / Getty Images).

Written by Eric Fèvre

‘There are fears that Africa’s next major modern disease crisis will emerge from its cities. Like Ebola, it may well originate from animals. Understanding where it would come from and how this could happen is critical to monitoring and control.

‘Growth and migration are driving huge increases in the number of people living in Africa’s urban zones. More than half of Africa’s people are expected to live in cities by 2030, up from about a third in 2007.

‘The impact of this high rate of urbanisation on issues like planning, economics, food production and human welfare has received considerable attention. But there hasn’t been a substantive effort to address the effects on the transmission of the organisms—pathogens—that…

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An Ethiopian woman breeds sheep for a living (photo credit: ILRI/Zerihun Sewunet).

On the matter of global health and tackling the looming threat of emerging infectious disease pandemics, Delia Grace, a veterinary epidemiologist at the International Livestock Research Institute (ILRI) shares her views in a recent blog post, Pandemic proofing the world, published by How We Get To Next.

The post argues the case for greater attention to diseases that can be transmitted to people through livestock, better incentive structures for reporting of livestock disease outbreaks so that timely disease reporting is rewarded rather than punished, and the need to tackle the root causes and not just the symptoms of emerging zoonotic diseases.

Read the post, Pandemic proofing the world by Delia Grace, How We Get To Next, 29 June 2016

Delia Grace presents on zoonotic diseases, UNEP Nairobi, 20 May 2016
ILRI veterinary epidemiologist Delia Grace presenting at the United Nations Environment Programme (UNEP) Science-Policy Forum that preceded the second session of the United Nations Environment Assembly (UNEA-2), on 20 May 2016 (photo credit: ILRI).

The United Nations Environment Programme (UNEP) held its first global Science-Policy Forum in Nairobi, Kenya on 19-20 May 2016 as part of the overall programme of the second session of the United Nations Environment Assembly (UNEA-2) held on 23-27 May 2016.

The forum offered a platform to the science community to engage with policymakers and civil society stakeholders on the science and knowledge needed to support informed decision-making to deliver on the environmental dimension of the 2030 Agenda for Sustainable Development.

Delia Grace, a veterinary epidemiologist at the International Livestock Research Institute (ILRI), took part in the forum as a panellist for the launch of the UNEP Frontiers 2016 report on emerging issues of environmental concern.

Her presentation on zoonotic and emerging infectious diseases focused on the global burden of zoonotic diseases (diseases that can be transmitted between animals and people), the drivers of disease (among them, land use change, environmental degradation and climate change) and how the multidisciplinary One Health approach can be used to support timely response to the threat of zoonotic diseases.

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Zoonotic diseases are also featured in a chapter in the UNEP Frontiers 2016 report, Zoonoses: Blurred lines of emergent disease and ecosystem health by Delia Grace and ILRI colleagues Bernard Bett, Hu Suk Lee and Susan MacMillan.

ILRI news

MERS-Coronavirus_NIADTransmission electron micrograph of Middle East Respiratory Syndrome coronavirus, MERS-CoV (image credit: NIAID). MERS-CoV belongs to the coronavirus family. Human coronaviruses were first identified in the mid-1960s; MERS-CoV was first reported in 2012 in Saudi Arabia. Coronaviruses can also infect animals. Named for the crown-like spikes on their surface, coronaviruses are common in people, usually causing mild to moderate upper-respiratory tract illnesses. Two exceptions are the MERS-CoV and the SARS (Severe Acute Respiratory Syndrome)-CoV.

A new study published in the science journal Emerging Infectious Diseases reports that two individuals in Kenya have tested positive for the presence of antibodies to Middle East Respiratory Syndrome coronavirus (MERS-CoV). Neither person is ill or recalls having any symptoms associated with MERS.

There is no evidence of a public health threat and scientists concluded that the infections caused little or no clinical signs of illness. But they plan follow-up studies, as this is the…

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AITVM conference logo 2016

The holistic concept of ‘One World-One Health’ in disease prevention and control will be among the topics of discussion at the first joint international conference of the Association of Institutions for Tropical Veterinary Medicine (AITVM) and the Society of Tropical Veterinary Medicine (STVM) which is scheduled to place on 4-8 September 2016 in Berlin, Germany.

AITVM is a foundation of 24 veterinary faculties and livestock institutes based in Africa, Asia and Europe with the mandate to improve human health and quality of life by means of increased and safe food production in tropical regions through enhancement of research, training and education in veterinary medicine and livestock production within the framework of sustainable development.

STVM is made up of scientists, veterinarians and students from more than 40 countries with common interests in tropical veterinary medicine. It is a non-profit organization whose purpose is the advancement of tropical veterinary medicine, hygiene and related disciplines.

The joint conference will bring together animal health and production experts, senior and junior career researchers and students from all over the world to discuss research and development topics including animal and zoonotic disease control, food safety, genetic resources and biodiversity, rural development and animal production, training and capacity building and animal welfare.

The conference is organized by the Institute for Parasitology and Tropical Veterinary Medicine and the Food and Agriculture Organization of the United Nations Reference Centre for Veterinary Public Health of the Freie Universität Berlin.

The co-organizing institutions are:

  • the Friedrich-Loeffler Institute – Federal Research Institute for Animal Health
  • the Federal Institute for Risk Assessment
  • the German Veterinary Medical Society
  • Vétérinaires Sans Frontières Germany
  • the Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences of the Humboldt-Universität zu Berlin

The conference organizers are now accepting abstracts. The deadline for submission of abstracts is 15 March 2016.

Visit the conference website for more information.

Catch of the day, Khulna, Bangladesh. Photo by Yousuf Tushar.

Catch of the day, Khulna, Bangladesh. Fish are among the aquatic hosts of microsporidia, a group of emerging foodborne parasites. (photo credit: WorldFish/Yousuf Tushar).

In December 2015, the World Health Organization published a report of the first ever global and regional estimates of the burden of foodborne diseases.

The report estimates the burden of foodborne diseases caused by 31 agents – bacteria, viruses, parasites, toxins and chemicals – and shows that almost 1 in 10 people fall ill every year from eating contaminated food and 420,000 die as a result.

Children under five years of age are at particularly high risk, with 125,000 children dying from foodborne diseases every year. Africa and Southeast Asia have the highest burden of foodborne diseases.

Microsporidia are among the many contributors to the global burden of foodborne disease, although they are not currently considered to be priority foodborne parasites.

Microsporidia are a group of spore-forming parasites that infect a wide range of host organisms, including humans. People can get infected with microsporidia through ingesting contaminated food and water. People with weakened immune systems are at particularly high risk of infection.

To address the growing threat of this emerging group of pathogens, a group of experts met at a symposium entitled “Microsporidia in the animal to human food chain: An international symposium to address chronic epizootic disease”. The meeting was sponsored by the Organisation for Economic Cooperation and Development and held in Vancouver, Canada in August 2015.

Kristina Roesel, a scientist at the International Livestock Research Institute (ILRI), presented a paper entitled “Parasites in food chains”. Her presentation contributed to a collaborative review article, “Microsporidia – Emergent pathogens in the global food chain”, published in the journal Trends in Parasitology (18 Jan 2016).

The article examines the threat of microsporidia in food, water and major food production chains. The authors note that climate change may result in a greater disease burden in hosts from all environments and thus increase the contact rate between infected animals and humans. A One Health approach will, therefore, be useful to manage the risks of microsporidian infections in wildlife, food animals and humans.

Orma Boran cattle crossing a river in Kenya

Orma Boran cattle crossing a river in Kenya (photo credit: ILRI/Rosemary Dolan).

The Dynamic Drivers of Disease in Africa Consortium is a research program that works to understand the relationships between ecosystems, zoonotic diseases, health and wellbeing in order to inform effective public health interventions.

Under this program, multidisciplinary country teams are studying four zoonotic diseases: henipavirus infection in Ghana, Lassa fever in Sierra Leone, Rift Valley fever in Kenya and trypanosomiasis in Zambia and Zimbabwe. The focus is on how changes in biodiversity, land use and climate affect disease transmission.

The development of irrigation schemes is thought to influence pathogen transmission in people and animals in several ways. For example, masses of stagnant water and high humidity support the development of disease vectors like mosquitoes. In addition, irrigated areas are likely to have a higher density of animal hosts like chicken and small ruminants.

In order to investigate the influence of irrigation and changes in biodiversity on the distribution of zoonoses, a cross-sectional study was carried out in Tana River County, Kenya, home to the Hola Irrigation Scheme. The zoonoses of interest were Rift Valley fever, Q fever, brucellosis, West Nile virus, dengue fever and leptospirosis.

Irrigation causes a decline in biodiversity as wildlife habitats are cleared to make way for crop agriculture. However, the linkages between biodiversity and disease risk remain unclear. It was also found that areas with a rich diversity of hosts have higher prevalence of multiple zoonotic pathogens as compared to areas with lower host diversity.

The study also found that while irrigated areas are infested with multiple species of mosquitoes (including primary vectors of Rift Valley fever), their high population densities alone are not enough to sustain the transmission of pathogens; reservoir hosts (for example, birds for West Nile virus) or other persistence mechanisms are required.

These and other findings from the study were presented at the 49th annual scientific conference of the Kenya Veterinary Association which was held in April 2015.

View the presentation, Land use, biodiversity changes and the risk of zoonotic diseases: Findings from a cross-sectional study in Tana River County, Kenya

Farming in the highlands of Ethiopia

Farming scene in the highlands of Ethiopia (photo credit: ILRI/Apollo Habtamu).

 

Zoonotic diseases, or zoonoses, are diseases that can be passed from animals to people. Nearly two-thirds of emerging infectious diseases affecting people are zoonotic and about 60% of all human pathogens are zoonotic.

Zoonoses such as brucellosis, anthrax and rabies are endemic in eastern Africa and yet formally published research studies on zoonoses in the region are hard to come by; useful research findings remain tucked away in the libraries of universities and other research institutions in form of working papers and students’ theses: the so-called ‘grey literature’.

In order to bring to the fore the wealth of unpublished research on zoonoses from studies carried out in Burundi, the Democratic Republic of the Congo, Ethiopia, Kenya, Rwanda, South Sudan, Tanzania and Uganda, the first-ever regional conference on zoonotic diseases in eastern Africa was held in Naivasha, Kenya on 9-12 March 2015.

The conference brought together academicians, researchers and graduate students from across Africa who presented on topics such as the One Health approach to disease prevention and control, the global health security agenda, the recent Ebola outbreak and its control, and control of rabies in East Africa.

Some 80 oral and poster presentations covered a wide range of aspects of research on zoonotic diseases including epidemiology, antimicrobial resistance, diagnosis, surveillance, outbreak investigations, disease modelling and foodborne zoonoses.

Bernard Bett, a veterinary epidemiologist at the International Livestock Research Institute (ILRI), gave a keynote presentation on behalf of the institute’s director general Jimmy Smith detailing how research by ILRI is contributing towards healthy people, animals and ecosystems.

Food insecurity remains a challenge for millions of people in the region. Animal-source foods can play a role in improving food and nutritional security, particularly in developing countries where demand for meat, milk and eggs is on the rise. Thus, food security is linked to the health of the livestock that produce these food products.

However, because of the threat of endemic and emerging zoonotic diseases, human health is influenced by animal health. Furthermore, changing patterns of land use, such as irrigation and intensified farming, can have an impact on the life cycles of vectors that spread diseases that affect both animals and people. Therefore, the impact of agriculture on ecosystem health also needs to be considered when tackling animal and human health challenges.

View the presentation “Healthy people, animals and ecosystems: The role of CGIAR research
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The contribution of livestock to human and animal health was among the several topics discussed at a high-profile conference organized by the International Livestock Research Institute (ILRI) in Addis Ababa, Ethiopia on 6-7 November 2014. The theme of the conference was Livestock-based options for sustainable food and nutritional security, economic well-being and healthy lives.

The conference was the culmination of a series of events organized this year to mark 40 years of livestock research by ILRI and its predecessors, the International Laboratory for Research on Animal Diseases (ILRAD) and the International Livestock Centre for Africa (ILCA).

Discussions under the sub-theme of ‘livestock and healthy lives’ began on the morning of the first day of the conference with a featured talk by Lorne Babiuk, vice president for research at the University of Alberta on how healthy animals can improve the health, welfare and economy of people.

Lorne Babiuk, vice-president for research at the University of Alberta

Lorne Babiuk presents a featured talk titled Healthy animals equals healthy, productive people at the ILRI@40 conference held on 6-7 November 2014 in Addis Ababa, Ethiopia (photo credit: ILRI/Apollo Habtamu).

In his presentation, Babiuk noted that smallholder farmers dominate livestock production in many developing countries and globally, one billion poor people depend on livestock for their livelihoods.

However, despite the potential of smallholder livestock production to contribute to meeting the growing demand for animal protein in the developing world, the livestock sector is beset by several challenges such as emerging diseases and limited natural resources for raising livestock.

Zoonotic diseases, in particular, have impacts on international trade, food prices and human health.

Babiuk then discussed three biotechnology options that can be used to improve livestock production: vaccines, breeding and selection of disease-resistant animals, and marker-assisted management to produce better quality carcasses.

“Vaccination, in my opinion, has been one of the most cost-effective approaches for the management of infectious diseases,” he said.

“In fact, it’s been stated that vaccination has saved more lives than all other therapeutic interventions in the world.”

He also gave examples of how genetics can be used to improve productivity through classical breeding and selection and use of genomic tools.

Babiuk summed up his presentation by stating that increasing food security will become more critical as the world population increases and that “healthy animals equals healthy people equals healthy environment equals stable economic environments”.

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Continuing with the underlying theme of Babiuk’s talk, a roundtable discussion was held in the afternoon to examine the relationship between livestock, nutrition and health.

John McDermott, director of the CGIAR Research Program on Agriculture for Nutrition and Health, moderated the discussion. The panellists were Walter Masiga, the World Organisation for Animal Health sub-regional representative for eastern Africa; Juliana Rwelamira, managing director of Sasakawa Africa Association and Vish Nene, director of ILRI’s livestock vaccines initiative.

Vish Nene, Juliana Rwelamira and Walter Masiga, panelists at ILRI@40 roundtable discussion on livestock and healthy lives

Left to Right: Vish Nene (ILRI), Juliana Rwelamira (Sasakawa Africa Association) and Walter Masiga (World Organisation for Animal Health) take part in a roundtable discussion on livestock and healthy lives at the ILRI@40 Addis Ababa conference (photo credit: ILRI/Apollo Habtamu).

McDermott began with an overview of the controversial and somewhat counterintuitive role of livestock in nutrition.

He noted that while animal-source foods are important sources of nutrition for poor people in low-income countries, there is underconsumption of livestock products by the poor on account of the high price of meat, milk and eggs relative to that of cereals.

On the other hand, overconsumption of livestock products in high-and middle-income countries has led to an increase in cases of obesity and related non-communicable diseases, a trend that is starting to emerge in low-income countries as well.

McDermott also noted that while meat, milk and eggs are good sources of vital nutrients, there are considerable health risks associated with livestock and livestock products.

“The most nutritious foods are also the most risky. You’re not going to get very sick eating rice as compared to eating spoiled milk or meat,” he said.

Intensification of agriculture to increase the supply of livestock is also associated with environmental contamination and increase of microbial populations, he added, noting that three-quarters of emerging diseases are zoonotic.

The roundtable discussion sought to link the economic development agenda of the livestock sector with issues related to health and nutrition.

Among the topics discussed were the One Health approach for more effective control of emerging diseases; vaccines and diagnostics; value chain development to reduce postharvest food losses and improve food safety and nutritional quality; risk-based approaches to food safety in informal markets and strengthening of national control systems to prevent misuse of antibiotics in treatment of animals.

The outcomes of the discussions on livestock and health on the first day of the conference fed into a parallel session on the second day. The aim of the session was to look into the future to identify the key priority areas for research on livestock and health in the next 40 years.

About 20 participants, mostly veterinary practitioners, took part in the parallel session on livestock and healthy lives which began with three scene-setting PowerPoint presentations and one poster presentation by scientists from ILRI’s Food Safety and Zoonoses program:

Following the presentations, the participants split into three groups for an in-depth discussion of the identified priority areas for research on livestock and health in the next 40 years. The discussions were based on their individual experiences, the content of the three presentations and current global trends in animal and human health.

They identified the following three priority areas for research on livestock and health:

  • emerging infectious diseases;
  • vaccines and diagnostics; and
  • antimicrobial residues and resistance.

Research on emerging infectious diseases needs to focus on increased understanding of the drivers of disease, for example, agricultural intensification, climate change, new farming systems, irrigation and increased mobility of animals and people. Research activities could include mapping, modelling and analysis of vectors; vector control through the use of ‘green’ insecticides; biological control of vectors and adoption of the Ecohealth approach to disease prevention and control.

Research on vaccines should be aimed at developing safe, single-dose, affordable ‘combination’ vaccines that are easy to deliver and target multiple pathogens. Rapid diagnostics that can be used along the food chain and are linked into large databases for surveillance can provide early warning systems for quick detection and reporting of potential health hazards and timely intervention.

Research on antibiotic residues and resistance needs to ensure prudent use of antimicrobials for treatment of farm animals to avoid residues in animal-source food products. The transfer of antibiotic resistance from animals to milk, meat and eggs was also identified as an important research area.

Dieter Schillinger

Dieter Schillinger leads a group discussion on antimicrobial residues and resistance as a priority area for research on livestock and healthy lives (photo credit: ILRI/Apollo Habtamu).

The group summed up the vision of ILRI’s livestock-for-health research in the next 40 years as follows:

ILRI research has contributed to appropriate health management systems leading to healthy animals, people and ecosystems and increase animal-source food and income for all’.

Rift Valley fever, a viral disease that is endemic in sub-Saharan Africa, Saudi Arabia and Yemen, causes abortion and stillbirth in livestock and can cause serious conditions such as haemorrhagic fever and encephalitis in humans.

Download a brief that illustrates how scientists at the International Livestock Research Institute (ILRI) are working to identify key drivers for Rift Valley fever occurrence and transmission, and develop decision support tools to guide responses at various stages of the epidemic cycle of the disease.

Developed after the last devastating Rift Valley fever outbreak in Kenya in 2006-07, these research outputs are designed to enable decision-makers to take timely, evidence-based decisions to prevent and control future epidemics and reduce their impacts.

In particular, the Government of Kenya has incorporated the decision support tool in its Rift Valley fever contingency plan and local governments in the country regularly use outputs from ILRI’s work to assess their level of preparedness.

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