Cattle pneumonia pathogen arose with domestication of ruminants ten thousand years ago, researchers say

In this short (3:45 min) video interview, Joerg Jores, a molecular biologist at the International Livestock Research Institute (ILRI), shares new insights from his research on contagious bovine pleuropneumonia, a killer livestock disease endemic in Africa.

Jores describes a recent study by researchers from ILRI, the International Centre of Insect Physiology and Ecology and partners in Germany, Sweden, Switzerland and the USA that evaluated the history and relationships of pathogens that cause both cattle (contagious bovine pleuropneumonia) and goat (contagious caprine pleuropneumonia) pneumonia.

The study, ‘The origin of the “Mycoplasma mycoides cluster” coincides with domestication of ruminants,’ was published in the April 2012 edition of the Public Library of Science (PLoS, 27 Apr 2012). The researchers found that the bacterium Mycoplasma mycoides, which causes contagious bovine pleuropneumonia, arose at the same time as humans first started to domesticate wild ruminants.

The onset of domestication of livestock about 10,000 years ago, which established large ruminant populations and the herding of mixed species, is thought to have contributed to creating the conditions favouring the spread and diversification of the pathogens by allowing them to adapt to different hosts.

Contagious bovine pleuropneumonia can kill up to 80 per cent of animals in infected herds, and the surviving animals often carry the disease for long periods and can introduce it to uninfected herds.

‘This research was the largest comparative study of Mycoplasma mycoides cluster to date,’ says Jores. ‘Our findings are shedding light into the history of contagious bovine pleuropneumonia and this new knowledge is expected to guide future research into the disease.’

Read a related ILRI clippings article on the paper: Lethal family tree: ILRI research shows livestock bacterium is as old as the livestock it kills.

Download the paper: The origin of the Mycoplasma mycoides cluster coincides with domestication of ruminants, by Anne Fischer (ICIPE and ILRI), Beth Shapiro (Pennsylvania State University), Cecilia Muriuki (ILRI), Martin Heller (Friedrich-Loeffler-Institute), Christiane Schnee (Friedrich-Loeffler-Institute), Erik Bongcam-Rudloff (Swedish University of Agricultural Sciences), Joachim Frey (University of Bern) and Joerg Jores (ILRI), 2012, PLoS ONE 7(4): e36150.

 

One world, one health

Holistic approaches to controlling the 'perfect storm' of health problems in poor countries, particularly Africa's catastrophic disease burden, must include better control of diseases transmitted between animals and people.

A paper to be published this May 2006 in the Public Library of Science (PLoS) journal PLoS Medicine, a peer-reviewed open-access journal (available online at www.plosmedicine.org) advocates linking integrated work on ‘neglected’ tropical diseases with major global health partnerships recently formed to tackle the three most devastating diseases of the poor: malaria, TB and AIDS. The authors of the paper, which include development economist Jeffrey Sachs, argue that while new partnerships and initiatives have significantly raised funding and awareness of the need to scale up the fight against the ‘big three’ diseases, conspicuously absent is work on a group of ‘neglected tropical diseases’ that may threaten the poor as much as malaria, TB and AIDS and for which there are already cheap and effective control strategies. The authors propose that our success in controlling the big three may depend on a concurrent attack on this group of neglected diseases, which include three vector-borne protozoan infections (leishmaniasis, human African trypanosomosis and Chagas disease), three bacterial infections and seven kinds of helminth (worm) infections.

The potential benefits of taking a more holistic approach to disease control are being popularized in complementary initiatives advocating ‘one health’ strategies that simultaneously address human and animal health. (See, for example, a new book exploring grass roots ideas from East and Southern Africa on how to integrate wildlife, livestock and human health for both conservation and development: ‘One World, One Health’ is available online from LEAD, the Livestock, Environment and Development Initiative.

ILRI supports these holistic health approaches and further argues that another class of neglected diseases of the poor—‘zoonotic’ diseases, or those transmitted between people and animals—should be included. Zoonotic diseases account for a remarkable 75% of all human diseases and include such emerging diseases as avian influenza. Esther Schelling, a veterinary epidemiologist on joint appointment with the International Livestock Research Institute (ILRI) and the Swiss Tropical Institute, points out that zoonotic diseases are virtually excluded from most health initiatives ‘because they’re simply not accounted for’. ILRI is helping to ensure that they are accounted for and that methods to control them are friendly to the poor.

Two papers on this topic by Schelling and colleagues are available online:
British Medical Journal article
Lancet article

Carlos Seré, director general of ILRI, says that with the sequence in recent years of BSE (‘mad cow disease’), foot-and-mouth disease, and now bird flu, there is definitely increasing interest in zoonotic diseases.

‘Donors like the Welcome Trust’, he says, ‘are increasing their investment in tropical animal disease research. Our own strategy is to develop appropriate methods for researchers and policy-makers to evaluate the risk of these zoonotic diseases and together identify the most promising strategies and policies that can help to reduce such risk, particularly for the poor. We have activities specifically looking at zoonoses such as brucellosis and bovine TB, and we are building up our expertise in food safety issues. Strengthening our expertise on food safety and the risks posed by zoonoses is central to two of ILRI’s strategic research themes, the first on sustaining lands and livelihoods which involves protecting human health, and the second on improving livestock-related market opportunities in domestic and international markets, which are increasingly threatened by such food safety concerns.’

In relation to bird flu, Dr Seré explains, ‘ILRI will not be the virologists or poultry specialists. But we have comparative strength in systems analysis, which combines social science with epidemiology and animal genetics and other lab bench research to address complex health problems. We do this in conjunction with partners who bring more specific expertise, such as in poultry or vaccines. What we specifically bring to the picture is a “poverty lens” to understand the implications of health problems, issues and control strategies on the poorest populations in the world.’

‘Clearly, research is not a “rapid deployment tool”’, he says. ‘There are other organizations—such as the World Health Organisation (www.who.org), the Food and Agriculture Organization of the United Nations (www.fao.org), and the World Animal Health Organisation (www.oie.org) —that have a regulatory mandate and policy responsibility and are linked directly to governments. ILRI’s comparative advantage is in the longer term: in understanding the issues and in providing sound technical research to back these agencies which are doing the short-term response work. As we see more and more that boundaries don’t work, that disease is a global problem, we encourage industrialized countries to share their resources with developing countries, not just out of enlightened self-interest, but also, for example, to ensure food safety for their domestic consumers. And finally, we are particularly interested in helping developing countries to build their own research capacity to understand, model and control complex disease problems.