Animal Diseases


Cows walk along an irrigation canal in Niolo, Mali (photo credit: ILRI/Stevie Mann).

As part of a special COVID-19 series by the International Food Policy Research Institute (IFPRI), Bernard Bett and Delia Randolph of the International Livestock Research Institute (ILRI) and John McDermott of IFPRI write on the growing risk in Africa of pathogens that spread from animals to people and how we can learn from past epidemics to improve preparedness and response.

In their article, the scientists discuss the evolving patterns of emergence and spread of zoonotic pathogens, factors that might influence the spread of emerging zoonotic pathogens and the opportunities for controlling emerging infectious diseases in Africa. 

They write: “The record thus far on COVID-19 and on past disease outbreaks shows that early, effective and sustained response is essential to winning the battle over these diseases. Innovative use of information and communication tools and platforms and engagement of local communities are crucial to improved disease surveillance and effective response. Building these systems requires demand from the public and commitment from policymakers and investors.” 

Read the full article, Africa’s growing risk of diseases that spread from animals to people, originally posted on the IFPRI website.

Bernard Bett is a senior scientist with ILRI’s Animal and Human Health program, Delia Randolph is the co-leader of ILRI’s Animal and Human Health program and John McDermott is the director of the CGIAR Research Program on Agriculture for Nutrition and Health. The analysis and opinions expressed in the article are of the authors alone.

Borana women with sheep and goats at a traditional deep well water source, Garba Tulla, Isiolo, Kenya (photo credit: ILRI/Fiona Flintan).

Brucellosis is an important zoonotic disease that affects wildlife and livestock. People may get exposed to the disease through direct contact with an infected animal or consumption of raw or undercooked animal products. In humans, the disease is characterized by prolonged fever, body aches, joint pains and weakness, while in livestock, it mainly causes abortions and infertility. 

A study carried out in Garissa and Tana River counties of Kenya set out to identify the factors that affect the spread of brucellosis in people and livestock. Livestock and people from randomly selected households were recruited and serum samples were obtained and screened for Brucella antibodies to determine the level of exposure to Brucella spp. 

The study found that the chances of exposure to brucellosis in humans were at least three times higher in households that had at least one Brucella-seropositive animal compared to those that had none. 

This finding can be used to design risk-based surveillance systems for brucellosis, based on the locations of the primary cases of the disease, where each case of Brucella infection identified in livestock could signal potential locations of additional brucellosis cases in humans, and vice versa.

Citation

Kairu-Wanyoike, S., Nyamwaya, D., Wainaina, M., Lindahl, J., Ontiri, E., Bukachi, S., Njeru, I., Karanja, J., Sang, R., Grace, D. and Bett, B. 2019. Positive association between Brucella spp. seroprevalences in livestock and humans from a cross-sectional study in Garissa and Tana River Counties, Kenya. PLOS Neglected Tropical Diseases 13(10): e0007506.

The design of strategies for uptake of livestock vaccines by communities in East Africa should take into account that male and female farmers face different barriers in the uptake of the vaccines, a new research study says.

These barriers include the cost of the vaccines, distances to vaccination points, access to information on vaccination campaigns and decision-making processes at household level. Some constraints affect both men and women while others affect one gender group only, based on prevailing gender norms and division of labour.

The study, published in the journal Vaccines (8 Aug 2019), was undertaken by a team of scientists from the International Livestock Research Institute, Uganda’s Ministry of Agriculture, Animal Industry and Fisheries and the United States Agency for International Development Office of U.S. Foreign Disaster Assistance.

The work was carried out in purposively selected sites, namely, Kwale and Murang’a counties in Kenya and Arua and Ibanda districts in Uganda. The sites in Kenya were selected because livestock there had recently been vaccinated against Rift Valley fever while the sites in Uganda were chosen because they had experienced recent outbreaks of the disease but no vaccination was carried out. Data were collected through 58 focus group discussions (30 in Kenya and 28 in Uganda), with 8–12 discussants per group.

The researchers found that women in Kwale experienced more difficulties than their male counterparts in accessing information on vaccination campaigns while women in Ibanda had limited decision-making capacity over the management and control of livestock diseases because of culturally defined livestock ownership patterns. 

The cost of vaccines was a greater barrier for men than for women because the role of managing and controlling livestock diseases in these communities was culturally ascribed to men.

To be effective, therefore, livestock vaccination campaigns need to consider the socio-cultural gender dynamics that exist at household and community level. It is not enough to merely provide vaccines to the community during mass campaigns.

“Availability of vaccines does not guarantee uptake at community level due to social, spatial, economic and vaccine safety and efficacy barriers faced by men and women farmers,” the researchers note.

They add, “Vaccine uptake is a complex process which requires buy-in from men and women farmers, veterinary departments, county/district governments, national governments and vaccine producers”.

Citation

Mutua, E., Haan, N. de, Tumusiime, D., Jost, C. and Bett, B. 2019. A qualitative study on gendered barriers to livestock vaccine uptake in Kenya and Uganda and their implications on Rift Valley fever control. Vaccines 7(3): 86.

Taking sheep for disease testing in Bako, Ethiopia
Taking sheep for disease testing in Bako, Ethiopia (photo credit: ILRI/Barbara Wieland).

World Zoonoses Day is marked annually on 6 July to commemorate the day in 1885 when Louis Pasteur successfully administered the first vaccine against a zoonotic disease when he treated a young boy who had been mauled by a rabid dog. The day is also an opportunity to raise awareness of the risk of zoonoses, infectious diseases that are spread between animals and people. 

Scientists estimate that 60% of known infectious diseases in people and 75% of new or emerging infectious diseases in people are transmitted from animals. Neglected zoonoses associated with livestock, such as brucellosis and cysticercosis, impose a huge health burden on poor people and reduce the value of their livestock assets.

Through its Animal and Human Health program, the International Livestock Research Institute (ILRI) carries out research with national and international partners towards improving the control of zoonotic diseases through a range of tools and approaches such as risk mapping and risk targeting, modelling of zoonotic pandemics, decision-support tools and advice on vaccination strategies. The program also generates evidence for policymakers on the cost and impact of zoonoses and the benefits of their prevention.

Some of our collaborative research on zoonoses includes work on developing optimal vaccination strategies for Rift Valley fever in East Africa, studying the epidemiology, ecology and socio-economics of disease emergence in Nairobi and developing an effective surveillance program for zoonoses in livestock in Kenya.

For an in-depth look, listed below are some of our research publications on zoonoses:

For more information on ILRI’s research on zoonoses, contact Bernard Bett, senior scientist at ILRI (b.bett@cgiar.org) or Eric Fèvre, professor of veterinary infectious diseases, Institute of Infection and Global Health, University of Liverpool on joint appointment at ILRI (eric.fevre@liverpool.ac.uk).


Farmer herds his three bulls in Nikhekhu Village, Dimapur, Nagaland, India (photo credit: ILRI/Stevie Mann).

Rapid urbanization in India has led to expansion of peri-urban fringes, where intensive, industry-style livestock rearing has led to emerging vulnerabilities at the human-animal-environment interface.

To better understand the health system and farm-level factors that influence the risk of transmission of bovine tuberculosis in animals and humans, a qualitative study was undertaken among smallholder dairy farms in peri-urban zones in three cities in India: Guwahati, Ludhiana and Bangalore. Data were collected through literature reviews, expert consultations and in-depth interviews.

The study, published in BMC Public Health (March 2019), found that farmers consulted veterinarians as a last resort after home remedies and quacks had failed. Damage control measures, especially with respect to selling or abandoning sick animals, added to the risk of disease transmission.

Although civic authorities believed in the adequacy of a functioning laboratory network, end users were aggrieved at the lack of services. Despite the presence of extension services, knowledge and awareness were limited, promoting risky behaviour.

In addition, the absence of policies on the management of bovine tuberculosis may have influenced stakeholders not to consider it to be a major animal and public health concern.

“Evidence is needed not only about the burden and risks, but also on possible options for control applied in the local Indian setting,” the authors say.

The study also recommends that the identified gaps in knowledge be addressed through collaborative research and One Health interventions involving both animal and human health sectors.

Access the article Community, system and policy level drivers of bovine tuberculosis in smallholder periurban dairy farms in India: A qualitative enquiry by A.S. Chauhan and others.

To the grazing field, Afar, Ethiopia

Cattle going to the grazing field in Afar region, Ethiopia (photo credit: ILRI/Apollo Habtamu).

Climate change influences the occurrence and transmission of a wide range of livestock diseases through multiple pathways. Diseases caused by pathogens that spent part of their life cycle outside the host (for instance, in vectors or the environment) are more sensitive in this regard, compared to those caused by obligate pathogens.

A newly published book, The Climate-Smart Agriculture Papers, brings together some of the latest research by agricultural scientists on climate-smart agriculture in eastern and southern Africa. The 25 chapters of the book highlight ongoing efforts to better characterize climate risks, develop and disseminate climate-smart varieties and farm management practices, and integrate these technologies into well-functioning value chains.

In a chapter on climate change and livestock diseases, scientists from the International Livestock Research Institute (ILRI) use two well-studied vector-borne diseases—Rift Valley fever and tick-borne diseases—as case studies to describe direct pathways through which climate change influences infectious disease-risk in East and southern Africa.

Access the chapter, Climate change and infectious livestock diseases: The case of Rift Valley fever and tick-borne diseases by Bernard Bett, Johanna Lindahl and Delia Grace.

ILRI Clippings

African clay pots (via the Dick Jemison Tribal Arts Collection).

‘. . . Around 70 percent of all infectious diseases are zoonotic, moving from animals—usually livestock—to humans, through either contact or the consumption of animal products and by-products. The International Livestock Research Institute estimates that 2.7 million people die from zoonotic diseases each year, while approximately 2.5 billion people get sick. To offer some sense of scale, a recent study led by Lawrence Summers, former treasury secretary and former director of the National Economic Council at the White House, estimated that the costs of pandemic diseases—nearly all of which begin in animals—fall in the same range as those expected by climate change-related disasters.

‘”And yet only 4.5 percent of development money, of aid, goes to agriculture,” Carel du Marchie Sarvaas, executive director of the International Federation for Animal Health—the global trade association for leading animal pharmaceutical…

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