Animal Diseases


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 Clippings

TarniCooperPostersForInformedConsent_HigherRes

ILRI poster prepared by Tarni Cooper (concept and text), James Wakhungu (translation) and Timothy Hall (cartoons and design) as part of a What Is Killing My Cow? project in Tanzania. The poster was one of three communication tools used for seeking informed consent, which were tested and compared for participant comprehension (of project information) and engagement with the consent process.

English translations of Kiswahili captions: Box A: In the first part of the project, farmers said they want to know more about what is making their cattle sick. Box B: Farmer will choose 1–3 sick animals for sampling and the rest of the herd will only be examined at a distance. Box C: We will take milk samples in a clean, safe manner, to minimize risk. Box D: We will take blood samples in a clean, safe manner, to minimize risk. Box E: If necessary, we will restrain cattle on…

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The hidden dangers of irrigation in Kenya

By Imogen Mathers

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For farmers in Kenya, creative ways to irrigate crops can be the difference between a harvest failing or thriving. In this drought-prone country, access to reliable water sources is a daily challenge.

Few would argue with the need for better irrigation. Yet certain techniques introduced by the government to spur food production have dangerous side effects, warns Bernard Bett, a veterinary epidemiologist at the International Livestock Research Institute (ILRI) in Kenya.

The pools and canals that underpin flood irrigation create ideal conditions for mosquitoes to thrive, and are a draw for wildlife to gather and drink. This confluence of elements forms a perfect petri dish for zoonotic diseases such as malaria and dengue to circulate between wildlife, livestock, humans and insects.

Instead, Bett suggests exploring alternative techniques such as drip irrigation, a small change that can play a big part in keeping people safe from vector-borne diseases.

The interview was recorded on 18 March 2016 at One Health for the Real World, a symposium in the United Kingdom organised by the Dynamic Drivers of Disease in Africa consortium and the Zoological Society of London.

This article was originally published on SciDev.Net. Read the original article.

Cow in Kenya

Cow in Kenya. A new Rift Valley fever risk map for Kenya will help develop prevention and control measures to combat the disease in the country (photo credit: ILRI/Stevie Mann).

A new Rift Valley fever risk map for Kenya, based on data from a period spanning over 50 years, will be an important tool for use in developing measures to prevent and control the disease in the country.

Rift Valley fever is a viral disease that affects animals such as cattle, sheep, camels and goats. It is also a zoonotic disease, meaning it can be transmitted from animals to people.

Rift Valley fever epidemics occur every 3 to 10 years in specific regions of the Greater Horn of Africa, southern and western Africa and in the Arabian Peninsula, resulting in high rates of infection and death among people and livestock.

In Kenya, the most recent outbreaks of the disease occurred in 1997-98 and 2006-07. Experts agree that the severity of Rift Valley fever epidemics can be reduced through the use of effective early warning systems followed by rapid implementation of prevention and control measures.

In 2008, international experts and decision-makers from eastern Africa developed a risk-based decision support framework designed to guide responses during various stages of the Rift Valley fever disease cycle.

Now, a team of researchers from Kenya, the Netherlands and the United States of America has added to the arsenal of tools to prevent and control Rift Valley fever by using surveillance data from 1951 to 2007 to develop a Rift Valley fever risk map for Kenya.

The map shows the risk of an outbreak of the disease for each of the 391 administrative divisions in the country (based on the 1999 administrative map), classifying the divisions as high, medium or low risk.

The authors of the study say that the Rift Valley fever risk map will provide the Government of Kenya with an evidence-base from which it can respond to a Rift Valley fever epidemic warning as well as develop long-term prevention and control programs in high-risk areas.

The map is published in an article in the journal PLOS ONE (25 Jan 2016): Predictive factors and risk mapping for Rift Valley fever epidemics in Kenya

Citation
Munyua, P.M., Murithi, R.M., Ithondeka, P., Hightower, A., Thumbi, S.M., Anyangu, S.A., Kiplimo, J., Bett, B., Vrieling, A., Breiman, R.F. and Njenga, M.K. 2016. Predictive factors and risk mapping for Rift Valley fever epidemics in Kenya. PLOS ONE 11(1): e0144570.

Local breed sow and piglets on a farm in Masaka district, Uganda

Local breed sow and piglets on a farm in Masaka district, Uganda (photo credit: ILRI/Eliza Smith).

Zoonotic diseases are most dangerous when they take animal and human health workers by surprise, giving the public and disease control officials no advance warning or time to put prevention measures in place. The recent Ebola outbreak in West Africa illustrates the adverse consequences of trying to tackle a disease outbreak too late and with little information.

Ebola is a serious but mysterious disease; in Uganda, there is little solid information on the reservoir and transmission of Ebola. However, research findings in the last few decades have given rise to speculation that there could be associations between pigs and Ebola.

Currently, there is no evidence that pigs have had any role in past outbreaks of Ebola virus disease. But given the huge importance of pigs to the Ugandan economy, diet and livelihoods, it is important to investigate any potential links sooner rather than later.

A recent study by the International Livestock Research Institute (ILRI) argues there are several factors that support the potential role of pigs in the transmission of Ebola to humans in Uganda. It is critical that this hypothesis be investigated in order to understand the risks to the country’s burgeoning pig production industry.

A spatial representation of potential risk factors for zoonotic transmission involving pigs in Uganda could be used to initiate further investigations into Ebola and other zoonotic diseases known to affect pigs in Uganda.

The researchers call for a One Health approach to the continued research. The benefit of this multidisciplinary approach is that limited resources can be utilized efficiently to improve the health and livelihoods of Ugandans through enhanced food safety and security, and the preservation of important ecosystem services, such as those provided by bats and other wildlife.

Clear and consistent risk communication from all research partners will be of utmost importance in preventing hysteria and delivering good outcomes for wildlife conservation and livelihoods.

Download the policy brief, One Health approach recommended in investigating and communicating the potential role of pigs in transmitting Ebola in Uganda written by Eliza Smith of KYEEMA Foundation and Christine Atherstone and Delia Grace of ILRI.

Orma Boran cattle crossing a river in Kenya

Orma Boran cattle crossing a river in Kenya. Both cattle and people can be infected with Rift Valley fever (photo credit: ILRI /Rosemary Dolan).

Recent climate predictions suggest East Africa may be in line for an epidemic of Rift Valley fever – an infectious disease which can hit people, their livestock and livelihoods, and national economies hard.

Data from the Climate Prediction Center and International Research Institute for Climate and Society suggest there is a 99.9% chance there will be an El Niño occurrence this year, with a 90% chance it will last until March/April 2016.

At least two of the most recent Rift Valley fever epidemics in East Africa—those in 1997-98 and 2006-07—were associated with El Niño weather patterns, with Kenya suffering losses amounting to US$32 million.

Given the strong predictions of an El Niño occurrence, and the established association between El Niño and Rift Valley fever risk, countries in the Horn of Africa need to start preparing to manage the developing risk.

In particular, public education on the linkages between the expected weather patterns and disease risk is vital to minimize human exposure to the disease should an epidemic occur.

Read the full article by Bernard Bett, a veterinary epidemiologist at the International Livestock Research Institute (ILRI).

ILRI news

High-risk areas in Uganda for possible/potential pig transmission of Ebola

The map above shows high-risk areas due to a spatial overlap of three proposed risk factors for zoonotic Ebola virus transmission in Uganda: modelled zoonotic niche, domestic pig distribution and high numbers of people living in extreme poverty; the map is taken from a paper published in Transboundary and Emerging Diseases, Assessing the potential role of pigs in the epidemiology of Ebola virus in Uganda, by C Atherstone, E Smith, P Ochungo, K Roesel, D Grace, 27 August 2015 (figure credit: ILRI).

This article is written by two of this paper’s authors: Christine Atherstone, an ILRI researcher based in Uganda who leads this work and is lead author, and Delia Grace, who leads ILRI’s Food Safety and Zoonoses research program.

A new risk assessment paper, Assessing the potential role of pigs in the epidemiology of the Ebola virus in Uganda, was published in the science journal

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Livestock graze on an island in the Niger

Livestock grazing on an island in the River Niger, as seen off a bridge in Niger’s capital, Niamey (photo credit: ILRI/Stevie Mann).

The livestock sector contributes significantly to the global economy and to rural livelihoods. Globally, approximately one billion smallholder farmers keep livestock. However, the burden of animal disease in developing countries is high; livestock disease kills 20% of ruminants and over 50% of poultry each year, causing annual losses of approximately USD 300 billion.

A new report on climate and livestock disease by scientists from the International Livestock Research Institute (ILRI) shows that climate change can increase the burden of livestock diseases, and some diseases like Rift Valley fever and trypanosomosis are especially sensitive to climate change.

Climate change may also have indirect effects on animal diseases, for example, higher temperatures and greater humidity can lead to faster development of disease-causing parasites and pathogens.

In order to address climate impacts on the livestock sector, the authors make the following recommendations for policymakers:

  • Invest in ‘no regret’ adaptation responses. Many adaptation responses based on improving the control of climate-sensitive livestock diseases are ‘no regret’ options, which, by reducing the burden of livestock disease, will enhance community resilience, alleviate poverty and address global inequity irrespective of climate change.
  • Improve disease surveillance and response in order to detect changes in disease in a timely way, thus dramatically reducing the costs of response. This requires investment and innovation in disease reporting systems as well as laboratories capable of confirming diseases. Risk-based and participatory surveillance are promising options for improving disease reporting.
  • Increase the capacity to forecast near term occurrence of climate-sensitive diseases, and to predict longer-term distribution of diseases through better epidemiological information and ground-truthed models.
  • Improve animal health service delivery by investing in the public sector and supporting innovations in the private sector such as community animal health workers linked to private veterinarians. Promote One Health and ecohealth approaches to disease control, especially in vulnerable communities with high reliance on livestock (for example, pastoralists in East Africa).
  • Support the eradication of priority diseases where this is economically justified. Develop diagnostics and vaccines, and promote adoption of good practices and strengthened biosecurity to improve disease control.
  • Increase the resilience of livestock systems by supporting diversification of livestock and livelihoods, and integrating livestock farming with agriculture. Consider promotion of species and breeds that are more resistant to disease and climate change.
  • Adopt breeding strategies focused on identifying and improving breeds that are better adapted to climate change impacts and disease.
  • Understand the potential land use changes in response to climate change and monitor their impacts on animal disease to allow preventive or remedial actions.

The report was submitted to the Subsidiary Body for Scientific and Technological Advice (SBSTA) of the United Nations Framework Convention on Climate Change ahead of a special workshop on agriculture at the 42nd session of the SBSTA held on 1-11 June 2015 in Bonn, Germany.

An information note, Impact of climate change on African agriculture: focus on pests and diseases, gives a summary of the submission.

The CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS) and the CGIAR Research Program on Agriculture for Health and Nutrition (A4NH) supported the preparation of the report.

Citation
Grace D, Bett B, Lindahl J and Robinson T. 2015. Climate and livestock disease: assessing the vulnerability of agricultural systems to livestock pests under climate change scenarios. CCAFS Working Paper No. 116. Copenhagen, Denmark: CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS).

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

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