Global food security: The impact of veterinary parasites and parasitologists

https://doi.org/10.1016/j.vetpar.2013.04.005Get rights and content

Abstract

Global food security will require the production of more food using resources including land more efficiently, and with less waste. This goal must be achieved within the context of climate change and while ensuring minimal adverse environmental impact from both crop and livestock production. Disease, especially infectious disease, is a main constraint of biologically efficient livestock production and both endemic and exotic disease results in mortality and morbidity and hence less food than should ideally be available in current farming systems. A significant proportion of diseases affect the safety of food supplies, in addition to or instead of, their effect on volume and quality of food products. Parasitological diseases including those caused by nematodes, trematodes, protozoa and ectoparasites, have widely differing effects on meat, milk and fibre production and many new technologies have been developed in order to prevent or treat them. Approaches to developing better control of parasites have included livestock breeding strategies, improved nutrition and management, and the development of new drugs, diagnostic tests and vaccines. Some of the most important examples include both the development of new anthelmintic products, and better means of using existing drugs in order to maximise their effectiveness in the face of rapidly increasing parasite resistance; diagnostic tests which are able to detect low levels of nucleic acids or proteins from infectious agents rapidly; and vaccines derived from either native or recombinant proteins and designed to stimulate the most appropriate protective response from livestock species. Some of the parasitic diseases affect restricted regions around the world, however most affect very large global populations. The development of technologies of suitable and affordable livestock products for use in developing countries where most pressure on increased production for food will occur, provides a particular challenge. Most if not all new technologies form part of integrated management schemes on farms and these vary hugely in differing systems and geographical regions of the world. If the benefit of improved technologies for optimal health, welfare and biological efficiency of livestock is to be realised, then the veterinary, farming, commercial animal health and public service communities need to learn lessons from past successes and failures in the delivery of newly developed technologies to the farmer. The combination of technology and rural development in the veterinary parasitological field has played a key role in current food production and is well placed to continue this trend to help in ensuring future food requirements for the world.

Section snippets

Food

“Food Security” is on everyone's agenda, and the definition of this complex construct varies according to the author and the audience. For the purpose of this review, the definition that best fits is “Food security is the sustainable production of sufficient amounts of high quality, affordable, safe food required to underpin health and wellbeing of human populations world-wide”, with the subtext “Food from livestock” being the specific focus for those involved in veterinary parasitology.

The

Climate and environmental change

The world is becoming warmer with strong evidence of increases of between 1 and 3 °C (IPCC, 2007), however some modelling predicts much greater increases of up to 8 °C, with a 2 °C generally accepted as the most likely scenario (Moss et al., 2008). In drought-prone countries such as Africa, temperature increases may result in the loss of significant amounts of land to agriculture (Fischer et al., 2005). It is estimated that there will be considerable variation in temperature globally and including

Impact of livestock disease

When considering food security two broad aspects of infectious disease are relevant to the sustainability of supply of products from livestock species.

The first category are the prevalent diseases that clearly constrain efficient productivity through the inefficient use of input resources (pasture/forages, concentrates/bi-products, energy/fuel, manpower) and/or the unnecessary production of waste, including morbidity and mortality of animals resulting in extended periods of time prior to

Finding solutions through technology

“Technology” can be seen as the first principal component of Food Security, and probably of equal importance is the second, “Rural Development”.

Arguably one of the most exciting and productive periods in veterinary parasitology was the elucidation of the epidemiology and pathogenesis of many parasite species such as Ostertagia ostertagi and Ostertagia circumcinta (now Teladorsagia circumcinta) (Anderson et al., 1969); Dictyocaulus viviparous (Jarrett et al., 1957); and Fasciola hepatica (

Anthelmintic resistance

Anthelmintic resistance (AR) is currently a major issue in small ruminant production in many countries worldwide (Besier, 2007, Kaplan and Vidyashankar, 2012) and therefore, constrains sustainable agricultural systems. This is especially true in the southern hemisphere, where parasite species have long seasonal activity and frequent dosing with anthelmintic drugs is required. Anthelmintic resistance is also recognised as an increasing problem in cattle (Sutherland. and Leathwick, 2011). Many

Nematode vaccines

The abomasal worm, Haemonchus contortus, is generally recognized as the most pathogenic of the nematode species of small ruminants, with the blood-sucking activities of adult worms often resulting in severe anaemia and death. Haemonchus contortus is particularly prevalent in the warmer, regions of the world where sheep or goat rearing is extensive, especially New South Wales/Queensland in Australia, much of South Africa, and at similar latitudes in parts of Brazil, Argentina and Uruguay. It is

Parasitic gastroenteritis

Many years of research have been undertaken to develop vaccines against the abomasal nematodes, Ostertagia ostertagi in cattle and Teladorsagia circumcincta in sheep, parasites of particular relevance in temperate regions of the world. The impact of these infections is recognised to be through losses in production caused by inappetance and hypo-proteinaemia as a result of damage to abomasal tissues (Armour and Ogbourne, 1982). Evidence of increasing resistance to anthelmintics in both sheep and

Liver fluke

Liver fluke, caused by the trematode species, Fasciola hepatica in temperate regions and Fasciola gigantica in tropical regions, is responsible for acute, sub-acute and chronic manifestations in sheep and cattle, causing both mortality and loss in production including growth, milk production and fertility (Behm and Sangster, 1999). In terms of avoiding or reducing waste under the Food Security agenda, fluke has also been identified as the most common cause of condemnation of livers in abattoirs

Protozoa causing reproductive failure

Poor reproductive efficiency of livestock is one of the most significant constraints to sustainable food production (Ferguson, 1996). In ruminant species, infertility and abortion are common, and may be attributed to infectious disease, inappropriate genetics/breeding or poor management and nutrition, or a combination of all three (Sheldon et al., 2006). Loss of embryos or foetuses during pregnancy, or birth of non-viable or weak offspring, results not just in the loss of the youngstock, but

Sheep scab

Sheep scab has re-emerged as a major problem in the UK and elsewhere. Eradication of Psoroptes ovis was achieved in the UK in the 1950s, during which time the disease was notifiable with compulsory dipping in an approved sheep dip once a year in the autumn forming part of a national eradication scheme. A significant increase in sheep scab in the UK followed deregulation in 1992 with an estimated 7000 outbreaks per year in 2003/2004 (Bisdorff et al., 2006) and broadly co-incided with the

Tick vaccines

One of the original success stories in parasite vaccination was against the cattle tick, Rhipicephalus microplus. Research focused on native proteins extracted from the gut of semi-engorged adult female Rhipicephalus microplus by Dr Peter Willadsen and colleagues (Willadsen and Kemp, 1988). The most significant antigen identified and purified was Bm86, a membrane-bound glycoprotein which was a “concealed antigen”. Antibodies raised against Bm86 interacted with and destroyed digestive cells

Finding solutions through rural development

The second principal component of Food Security is “Rural Development”. If research is to have impact on Food Security, the results (knowledge) and outputs (vaccines, diagnostics and disease control strategies) need to reach the target audiences in a timely manner and in the most appropriate formats. Over the years and decades there have been many highly successful examples of two-way knowledge exchange between parasitologists and farmers and their veterinary surgeons and advisors. In the UK,

Contributions of parasitologists to food security

Livestock parasitologists have contributed to Food Security long before the term was coined. The value of the underpinning work of delineating the life cycles of parasites, their epidemiology and interactions with varied and, in some cases multiple hosts, cannot be argued against. In a similar vein, essential research on host-pathogen interactions has led to many of the outputs and progress toward practical solutions described above. Outstanding scientists have worked as individuals and as

Conflict of interest

J.L. Fitzpatrick is Scientific Director of the Moredun Research Institute and Chief Executive Officer of The Moredun Group. She is a Director of Moredun Scientific, a fully owned commercial subsidiary of the Moredun Foundation, and Director of Inocul8 Ltd., Wormvax UK Ltd. and Wormvax Australia. She is Chair of Food Security at the University of Glasgow, and Vice-Chair, Chair of the Technical Subcommittee and Trustee of GALVmed. As part of her role at Moredun she is also a Director of the

Acknowledgements

J.L. Fitzpatrick would like to thank all the parasitologists who kindly discussed the science, themes and issues explored in this review, especially those from the Moredun Research Institute and those who provided the personal communications detailed above.

References (155)

  • S.W. Culman et al.

    Long-term impacts of high-input annual cropping and unfertilized perennial grass production on soil properties and below ground food webs in Kansas, USA

    Agric. Ecosyst. Environ.

    (2010)
  • J.P. Dubey et al.

    Pathogenesis of bovine neosporosis

    J. Comp. Pathol.

    (2006)
  • J.P. Dubey et al.

    Diagnosis of bovine neosporosis

    Vet. Parasitol.

    (2006)
  • J.D. Ferguson

    Diet, production and reproduction in dairy cows

    Anim. Feed Sci. Technol.

    (1996)
  • B. Frayne

    Migration and urban survival strategies in Windhoek, Namibia

    Geoforum

    (2004)
  • S. Gaba et al.

    Experimental and modeling approaches to evaluate different aspects of the efficacy of targeted selective treatment of anthelmintics against sheep parasite nematodes

    Vet. Parasitol.

    (2010)
  • T.G. Geary et al.

    World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) Guideline: Anthelmintic combination products targeting nematode infections of ruminants and horses

    Vet. Parasitol.

    (2012)
  • J.S. Gilleard

    Understanding anthelmintic resistance: the need for genomics and genetics

    Int. J. Parasitol.

    (2006)
  • O. Golden et al.

    Protection of cattle against a natural infection of Fasciola hepatica by vaccination with recombinant cathepsin L1 (rFhCL1)

    Vaccine

    (2010)
  • C. Gokbulut et al.

    Comparative plasma disposition, bioavailability and efficacy of ivermectin following oral and pour-on administrations in horses

    Vet. Parasitol.

    (2010)
  • D.K. Gordon et al.

    On farm evaluation of the coproantigen ELISA and coproantigen reduction test in Scottish sheep naturally infected with Fasciola hepatica

    Vet. Parasitol.

    (2012)
  • E.A. Innes et al.

    Analysis of in vivo immune responses during Toxoplasma gondii infection using the technique of lymphatic cannulation

    Parasitol. Today

    (1995)
  • E.A. Innes et al.

    Protection against vertical transmission in bovine neosporosis

    Int. J. Parasitol.

    (2001)
  • R.M. Kaplan et al.

    An inconvenient truth: global worming and anthelmintic resistance

    Vet. Parasitol.

    (2012)
  • F. Kenyon et al.

    The role of targeted selective treatments in the development of refugia-based approaches to the control of gastrointestinal nematodes of small ruminants

    Vet. Parasitol.

    (2009)
  • A.J. Lee et al.

    Expression and characterisation of a Psoroptes ovis glutathione S-transferase

    Vet. Parasitol.

    (2002)
  • J.P. Lesschen et al.

    Greenhouse gas emission profiles of European livestock sectors

    Anim. Feed Sci. Technol.

    (2011)
  • M.W. Lightowlers et al.

    Vaccination against cestode parasites: anti-helminth vaccines that work and why

    Vet. Parasitol.

    (2003)
  • M.W. Lightowlers

    Eradication of Taenia solium cysticercosis: a role for vaccination of pigs

    Int. J. Parasitol.

    (2010)
  • P.S. Mellor et al.

    Chapter 11. Bluetongue in the Mediterranean Basin

  • C. Mercier et al.

    Dense granules: are they key organelles to help understand the parasitophorous vacuole of all apicomplexan parasites?

    Int. J. Parasitol.

    (2005)
  • G. Mulcahy et al.

    Immune responses of cattle to experimental anti-Fasciola hepatica vaccines

    Res. Vet. Sci.

    (1999)
  • A.J. Nisbet et al.

    Psoroptes ovis: identification of vaccine candidates by immunoscreening

    Exp. Parasitol.

    (2008)
  • F.G. Nunn et al.

    Development of a serodiagnostic test for sheep scab using recombinant protein Pso o 2

    Mol. Cell. Probes

    (2011)
  • T. Osawa et al.

    A multiple antigen ELISA to detect Neospora-specific antibodies in bovine sera, bovine foetal fluids, ovine and caprine sera

    Vet. Parasitol.

    (1998)
  • B.D. Perry et al.

    Improving the assessment of the economic impact of parasitic diseases and of their control in production animals

    Vet. Parasitol.

    (1999)
  • Armour, J., Ogbourne, C.P., 1982. Bovine Ostertagiasis: a review and annotated bibliography. Miscellaneous publication...
  • P.G. Bates

    Differences between primary and secondary infestations with the sheep scab mite Psoroptes ovis

    Vet. Rec.

    (2000)
  • P.G. Bates

    Therapies for ectoparasiticism in sheep

    Practice

    (2004)
  • C.C. Bassetto et al.

    Protection of calves against Haemonchus placei and Haemonchus contortus after immunisation with gut membrane proteins from H. contortus

    Parasite Immunol.

    (2011)
  • P. Bates et al.

    Attempts to immunise sheep against Psoroptes ovis (Sheep Scab)

  • M. Baylis et al.

    T7.3: The Effects of Climate Change on Infectious Diseases of Animals

    (2006)
  • R.N. Beech et al.

    Anthelmintic resistance: markers for resistance, or susceptibility?

    Parasitology

    (2011)
  • C.A. Behm et al.

    Pathology, pathophysiology and clinical aspects

  • R.B. Besier

    New anthelmintics for livestock: the time is right

    Trends Parasitol.

    (2007)
  • BIS, www.bis.gov.uk, Department for Business, Innovation &...
  • B. Bisdorff et al.

    Prevalence and regional distribution of scab, lice and blowfly strike in Great Britain

    Vet. Rec.

    (2006)
  • J. Benavides et al.

    High rate of transplacental infection and transmission of Neospora caninum following experimental challenge of cattle at day 210 of gestation

    Vet. Res.

    (2012)
  • J. Bruinsma

    The Resource Outlook to 2050: By How Much Do Land, Water and Crop Yields Need to Increase by 2050? Expert Meeting on How to Feed the World in 2050

    (2009)
  • J. Claridge et al.

    Fasciola hepatica is associated with the failure to detect bovine tuberculosis in dairy cattle

    Nat. Commun.

    (2012)
  • Cited by (0)

    View full text