It has long been recognized that some diseases in domestic animals are due wholly or partly to inheritance, with Darwin himself describing inherited conditions such as polydactyly in the dog and cat, and noting that there is a ‘unanimity of belief among veterinaries of all nations in the transmission of various morbid tendencies’ ( Darwin, 1865 ). Since Darwin’s time, numerous inherited diseases have been described in companion animals. This chapter discusses the canine and feline genome, basic genetics, diagnosis of genetic disease and DNA testing. This section includes case examples.

Viral infections of small animals are common and frequently represent an important cause of disease.Although precise diagnosis is not always necessary, it may be required to determine appropriate therapy and prognosis, and to give advice about the potential for disease in other susceptible animals sharing the same environment. This chapter deals with virus detection, antibody detection, feline viruses and canine viruses. The section concludes with case examples.

Diarrhoea is a common presentation in dog shelters, and can range from occasional low-level ‘grumbling’ problems to outbreaks with high mortality. This chapter explores the management of diarrhoea, with consideration of morbidity levels, aetiology, environmental management and the potential for cross-species transmission, including zoonosis. Case examples: Parvovirus at the local rehoming shelter; Rehoming a Campylobacter-positive dog.

Haemostasis is a simple word that means ‘stop bleeding’. Yet the simplicity of the word belies the incredible complexity of a process whereby an array of cells and proteins intimately interact in a finely tuned and balanced system, first to form a fibrin clot then to dissolve the clot to restore vessel patency. This chapter considers an overview of haemostasis, diagnostic assays for haemostasis and disorders of haemostasis. Case examples are included.

Plasma protein abnormalities are associated with a wide variety of disease processes and are a significant biochemical finding in both dogs and cats. The plasma proteins are comprised of albumin, globulin and fibrinogen fractions. The chapter considers methods of measuring protein, serum protein electrophoresis, functions of plasma proteins, hyperproteinaemia, hypoproteinaemia and acute phase proteins. The chapter also includes case studies.