Agotamiento escolar y salud

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damage to the vascular endothelium by toxins and infectious agents. Anasarca is a form of edema of the subcutaneous tissues. Ascites is an accumulation of fluid in theperitoneal cavity.

Hydrothorax is an accumulation of fluid in the pleural cavity.

Bruises:Bruises are frequently found on food producing animals andpoultry. In cattle bruises caused by transportation or handling are commonly found in the hip, chest andshoulder areas;

in pigs within the ham and in sheep in the hind leg. Bruises and hemorrhages in the hipjoint are caused by rough handling of animals during shackling. Bruises in poultry can be localized orgeneralized and are frequently associated with bone fractures or ruptured ligament tendons.

Tumours: A tumour is an abnormal mass of tissue which grows without control and uncoordinated with the tissue ororgans of origin or those nearby. Its presence if often cumbersome to the tissue or organ it arose either bypressure or by replacement of normal functional tissue. Tumour cells resemble healthy cells howeverserve no useful purpose. The term tumour in current medical lexicon is presently limited to neoplasticgrowths.Tumours are usually divided according to tissue of origin i.e. epithelial, mesenchymal (connective tissue), haemopoietic, nervous etc. Tumour behavioral classification include their mode of growth and the degreeof invasiveness. Slow growing non-invasive circumscribed tumours are considered benign and fastgrowing, infiltrative and frequently metastatic are malignant tumours. The spread of neoplasm is by directexpansion and infiltration, via lymphatics and blood circulation and by implantation.

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zoonotic pathogens, it isof major importance to consider both emergingagents – e.g. Severe acute respiratory syndrome(SARS) associated coronavirus (-CoV), Nipahvirus, Hantaviruses, prion protein, avian influenza– and re-emerging diseases, e.g. rabies, bovinebrucellosis, yellow fever and bovine tuberculosis.

Fig. 23: The host-parasite ecological continuum (here parasites include viruses and parasitic bacteria). (Source: Saegermanet al., 2012).

Examples of zoonosesare the following:

• Viral diseases:

• Avian influenza

• Equine encephalitis virus

• Bacterial diseases:

• Psittacosis (parrot fever) caused by Chlamydophilapsittaciand spread from birds.

• Salmonellosis caused by salmonella bacteria that infect many species of animals.

• Anthrax caused by Bacillus anthracis, infecting, for instance, cattle.

• The prion-based disease variant Creutzfeldt-Jakob disease (vCJD),

• Trichinosis caused by the larval stage of the roundworm—T. spiralis.

• Cryptosporidiosis is an emerging zoonotic protozoan disease.

4.0 CONCLUSION

You have learned the definitions of different veterinary terms especially that infectious, non-infectious, contagious diseases and zoonotic disease which was specifically defined as an infectious disease spread from animals to people.These diseases are important because they reduce productivity of livestockproduction through animal mortalities, through depressed growth rates, lower reproductive efficiency, and increased spontaneous abortion. It has been

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reported recently that 1415 pathogens infecting humans and theirdomestic mammals and identified 56.5% as being zoonotic and that 75% of theemerging diseases originate from domestic or wild animals. This has prompted the recent close collaborationbetween animal and public health authorities.On economic scale, animal diseases impact commerce and the price of animal products with the exporting of livestock or animal products restricted when there is a disease outbreak. For instance, the persistence occurrence of foot and mouth disease (FMD) in African cattle populations limits the exports of beef products to major global markets.

5.0 SUMMARY

In this unit, you have been informed thatanimal diseases are serious threats to humans‘ well-being, especially in developing countries like Nigeria where animal health care are poorly developed.The infectious diseases wereintroduced under the types of organisms thatcause them from viruses to bacteria and parasites.Mastitis was specifically introduced as a disease dairy cattlethat resultsin much-reduced milk production, the loss of milk not saleable with a high concentrationof somatic cells (leukocytes), and long-term damage to the mammarygland.Tuberculosis was also introduced as a chronic disease of many animal species and poultry caused by bacteria of the genusMycobacterium and characterized by development of tubercles in the organs of most species, with bovine tuberculosis being of special importance in meat inspection.The most important pathogenic tapeworms to humans are the porktapeworm (Tenia solium), beef tapeworm (Tenia saginata) and also the beef tapeworm causes cysticercosis in cattle.Interestingly, the group of emerging zoonotic pathogens such as Severe acute respiratory syndrome(SARS) Nipahvirus, Hantaviruses, prion protein, avian influenza and re-emerging diseases, such rabies, bovinebrucellosis, yellow fever and bovine tuberculosis are most endemic in tropical developing countries where there is urgent need to improve animal protein intake.

6.0 TUTOR-MARKED ASSIGNMENT

1. Discuss the impact of animal diseases on livestock production

2. List three each of the viral, bacterial parasitic and non-infectious diseases. Draw an annotated diagram of the beef and pork tape worms

3. Discussanimal diseases transmitted to humans. What are the impacts of tuberculosis on meat?

7.0 REFERENCES/FURTHER READING

D. Herenda, P.G. Chambers, A. Ettriqui, P. Seneviratna and T.J.P. da Silva (1994). Manual on meat inspection fordeveloping countries. Food and Agriculture Organization of the United Nations, Rome.

C. Saegerman, F. Dal Pozzo and M. Humblet (2012).Reducing hazards for humans from animals: emerging and re-emergingzoonoses. Italian Journal of Public Health,9(2):

C. Scanes (2011). Fundamentals of animal science. Delmar/Cengage Learning, New York, USA.

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R.G. Bengis, F.A. Leighton, J.R. Fischer, M. Artois, T. Mörner, & C.M. Tate (2004). The role of wildlife in emerging and re-emerging zoonoses.Rev. Sci. Tech. Off. Int.

Epiz.,23(2): 497-511.

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