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Pathogens affecting beef James E. Wells and Elaine D. Berry, US Meat Animal Research Center, USDA-ARS, USA 1 Introduction 2 Zoonotic diseases related to cattle: anthrax, bovine spongiform encephalopathy (BSE), brucellosis and tuberculosis 3 Zoonotic parasites and viruses related to cattle: Cryptosporidium, Giardia and haemorrhagic fevers 4 Major zoonotic pathogens related to cattle: Escherichia coli., Salmonella and Campylobacter 5 Additional pathogens related to cattle: Leptospira, Listeria and other pathogens 6 Pathogen control: good animal management and biosecurity practices 7 Pathogen control: use of vaccines 8 Pathogen control: non-traditional interventions 9 Summary and future trends 10 Where to look for further information 11 References

1 Introduction Prior to the early 1900s in the United States, the handling of foods, specifically meat, was not consistent and oversight was according to laws in each state in which a facility was located. The development and maturation of transportation allowed the rapid movement of live animals and distribution of meat products, and, as a consequence, the meat industry concentrated in major midwestern U.S. cities where labour, particularly immigrant labour, was abundant. Federal oversight was negligible for domestic meat production until The Jungle written by Upton Sinclair was published in 1906. The intent of the book was to highlight the plight of immigrants in the Chicago slaughterhouses, but the vivid description of the unhygienic slaughterhouse operations and the improper preparation and handling of product led to a public outcry for government regulation. Following a government investigation, the Federal Meat Inspection Act (FMIA) and the Pure Food and Drug Act were quickly passed in the same year. The FMIA mandated the inspection of livestock before slaughter (antemortem), the carcasses after slaughter (postmortem) http://dx.doi.org/10.19103/AS.2016.0008.01 Š Burleigh Dodds Science Publishing Limited, 2016. All rights reserved.


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Pathogens affecting beef

and sanitary standards as well as authorized the U.S. Department of Agriculture (USDA) to monitor and inspect facilities for slaughter and processing. The inspections required by FMIA provided consumers with assurances that animals were healthy and meat from these animals was wholesome. Following a 1992–3 outbreak of illnesses linked to Escherichia coli O157:H7, a Shiga-toxin-producing strain of Escherichia coli (STEC), in ground beef, the Food Safety Inspection Service (FSIS) of the USDA established that E. coli O157:H7 was to be considered an adulterant in raw ground beef and sale of this contaminated raw product was prohibited (FSIS, 1994). This ruling by the FSIS was revolutionary in that a specific pathogen was regulated in raw meat, and subsequently FSIS established that other STEC in addition to E. coli O157:H7 were to be considered as adulterants of raw ground beef and non-intact raw beef products (FSIS, 1999, 2012). Microscopic organisms, or microorganisms, are ubiquitous in nature. Microorganisms are diverse in form and function and include protozoa, bacteria, archaea (previously known as archaebacteria) and viruses. Microorganisms can affect animals in multiple ways. Close associations (Fig. 1) between animal hosts and microorganisms are symbiotic relationships and the type of interaction could be commensal (little benefit or cost), mutualistic (benefits one or both) and parasitic/pathogenic (cost/death to the host). Pathogenic microorganisms are typically either bacterial or viral, and not only affect the health and well-being of an animal, but may lead to death. In addition to pathogenic microorganisms, viroids and prions are misfolded proteins that can be infectious to a host, with prions affecting animals and viroids typically affecting plants. Cattle may harbour a number of pathogenic agents that can infect humans, and most of the agents are bacteria. Cattle are reservoirs for a number of diseases and, depending on the pathogen, transmission can occur via animal contact or consumption of meat or milk (Table 1). Animal

Figure 1 Representation of interactions between an animal host and microorganisms associated with that host. Interactions can be beneficial, costly or deadly to the host. © Burleigh Dodds Science Publishing Limited, 2016. All rights reserved.


Pathogens affecting beef3 Table 1 Pathogenic agents affecting cattle and cattle production that may impact human health. Traditional pathogenic agents are those zoonotic agents that through history of animal domestication have affected cattle and humans, but today in most developed countries, transmission to humans is rare. Pathogenic agent from cattle

Disease(s) in humans

Type of agent

Traditional agent of concern

Contemporary agent of concern

Bacillus anthracis

Anthrax

Bacterial

X

Brucella abortus

Brucellosis

Bacterial

X

Campylobacter spp. (C. coli and C. jejuni )

Campylobacteriosis

Bacterial

X

Cryptosporidium spp. (Cryp. parvum)

Cryptosporidiosis

Protozoan

X

Giardia spp. (G. duodenalis and G. enterica )

Giardiasis

Protozoan

X

Leptospira spp. (Lept. borgpetersenii Hardjo and Lept. interrogans Pomona)

Leptospirosis

Bacterial

Listeria spp. (List. monocytogenes and List. ivanovii )

Listeriosis

Bacterial

X

Nairovirus

Crimean-Congo haemorrhagic fever

Viral

Xa

Phlebovirus

Rift Valley haemorrhagic fever

Viral

Xa

PrPsc

Bovine spongiform encephalopathy

Prion protein

X

Salmonella enterica subsp. enterica serotypesb

Salmonellosis

Bacterial

X

Shiga-toxigenic, Escherichia coli (E. coli O157, E. coli O26, E. coli O45, E. coli O103, E. coli O111, E. coli O121 and E. coli O145)

Haemorrhagic colitis and haemolytic uraemic syndrome

Bacterial

X

Mycobacterium tuberculosis complex spp. (M. bovis and M. caprae)

Tuberculosis

Bacterial

X

X

Contemporary pathogenic agents are those zoonotic agents that are recently recognized as zoonotic organism from cattle production, and many of these agents are of primary concern in many developed countries. These agents are not currently found in cattle production in developed countries and are limited to certain regions in the world, but are a growing concern as human illness has spread. b There are nearly 1500 Salmonella enterica serotypes and Table 2 lists the specific serotypes associated with most human illnesses in the United States and the specific serotypes often observed in cattle production. a

© Burleigh Dodds Science Publishing Limited, 2016. All rights reserved.

Pathogens affecting beef  

Mankind has long recognized that animals harbour disease. Zoonotic pathogens are agents from animals that cause disease in humans. This chap...

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