Pathomorph. II - Infectious diseases

Question 1

The mechanism of injury in respiratory anthrax is

Answer 1

cell death caused by bacterial toxins (Bacillus anthracis) that act directly on cell membranes leading to acute coagulative necrosis.

Question 2

Resp. anthrax Gross lesions include (3)

Answer 2

pulmonary and lymph node edema, hemorrhage,
and necrosis.

Also, the spleen will be enlarged and unclotted blood will exit from cut surfaces.

Question 3

Septicemic anthrax’s vascular collapse results from?
Septicemic anthrax is characterized by?

Answer 3

vascular collapse occurs, resulting from massive release of toxins into the blood.

characterized by animals found dead unexpectedly, often in a classic sawhorse stance and with hemorrhage (unclotted) from body orifices.

Question 4

Clotting and anthrax.

Answer 4

Anthrax toxins also disrupt the clotting cascade likely through massive activation of DIC and consumption of clotting factors, resulting in un-clotted blood at body orifices and within tissues and organs.

Question 5

Cutaneous lesions in erysipelas are caused by

Answer 5

Erysipelothrix rhusiopathiae and are the result of bacterial embolization to the skin during sepsis.

Question 6

Erysipelas lesions consist of square to rhomboidal, firm, raised, pink to dark purple areas caused by (3)

Answer 6

vasculitis,
thrombosis, and
ischemia (infarction).

Question 7

difference between infarction and ischemia

Answer 7

The term ischemia means that blood flow to a tissue has decreased, which results in hypoxia, or insufficient oxygen in that tissue,

whereas infarction goes one step further and means that blood flow has been completely cut off, resulting in necrosis, or cellular death.

Question 8

Diamond skin disease (Erysipelothrix rhusiopathiae):
The mechanism of injury in diamond skin disease is

Answer 8

cell death and infarction of skin secondary to cutaneous vasculitis.

The rhomboidal shape likely represents an area of skin supplied by a thrombosed vessel.

Question 9

Erysipelothrix rhusiopathiae is likely a commensal organism that resides in

Answer 9

a biofilm of the mucosae of the pharynx and tonsillar epithelia of healthy pigs.

Question 10

Pathogenic spp. of Salmonella.

Answer 10

All known species of Salmonella are pathogenic, and salmonellosis is an important zoonosis .

Question 11

The second most common food-borne pathogen in humans.

Answer 11

Salmonella typhimurium is the second most common food-borne pathogen in humans.

Question 12

Salmonella serovars most often isolated from diseased animals include: (5)

Answer 12

Salmonella typhimurium, Salmonella enterica,

Salmonella dublin,
Salmonella choleraesuis, and Salmonella typhosa.

Question 13

Forms of Salmonellosis (3)

Answer 13

septicemic, acute enteric, or chronic enteric

Question 14

Percentage of cat/dog asymptomatic salmonella carriers.

Answer 14

Although dogs and cats rarely get clinical salmonellosis, 10% are carriers and can infect their human companions.

Question 15

What is a verotoxin?

Answer 15

Another name for shiga toxins (produced by certain strains of ecoli).

Question 16

Type of diarrhea seen in salmonellosis.

Answer 16

Inflammatory cells upregulate PGE2, which results in hyper secretion of chloride.

Secretory diarrhea results, as well as malabsorptive diarrhea from enterocyte death.

Question 17

Peracute Salmonella septicemia is a disease of (3)

Answer 17

calves, foals, and pigs.

Young animals are generally at greater risk than older animals, although the reasons for this difference are not understood.

In foals, the feces of affected animals is typically green.

Question 18

The serovar of Salmonella most often involved in septicemic salmonellosis is

Answer 18

Salmonella choleraesuis.

Question 19

Gross lesions of animals dying of peracute Salmonella septicemia are

Answer 19

are minimal and are caused by fibrinoid necrosis of blood vessels.

Necrosis of blood vessels causes widespread petecchiation and a cyanosis of the extremities and ventrum of white pigs.

Fibrinous polyserositis may be present.

Question 20

Peracute Salmonella septicemia is usually fatal in

Answer 20

animals 1 to 6 months of age.

Death is usually attributable to DIC secondary to the generalized Shwartzman reaction.

Question 21

What is the Shwartzman reaction?

Answer 21

is a rare reaction of a body to particular types of toxins, called endotoxins, which cause thrombosis in the affected tissue.

Question 22

acute enteric salmonellosis Characteristics of the disease

Answer 22

diffuse catarrhal enteritis

Mesenteric lymphadenopathy is usually present.

Question 23

Pasteurellosis is

Answer 23

a Pneumonic (lung/respiratory) or systemic disease, can also present as a haemorrhagic septicaemia.

Question 24

Chronic enteric salmonellosis characteristics

Answer 24

discrete foci of necrosis and ulceration, principally in the cecum and colon. These are termed button ulcers.

Question 25

The mechanism of injury in strangles is

Answer 25

coagulative necrosis of cells of lymphatic vessels, lymph nodes, and the monocyte-macrophage system attributable to acute suppurative inflammation and its mediators and degradative enzymes.

Question 26

Causative agent of strangles.

Answer 26

Streptococcus equi ssp.

Question 27

Glanders is a disease of

Answer 27

lymphatic vessels (and surrounding integument) and of the respiratory system.

Question 28

Bovine tuberculosis, the prototype for granulomatous pneumonia, is characterized by

Answer 28

the presence of a few or many caseated granulomas.

Calcification of the granulomas is a typical finding in bovine tuberculosis.

If dissemination is sudden and massive, mycobacteria are widely disseminated, and numerous small foci of infection develop in many tissues and organs and the process is referred to as miliary tuberculosis (like millet seeds).

Question 29

(such as in tuberculosis)
Microscopically the tubercle is composed of

Answer 29

mononuclear cells of various types.

In young tubercles, which are noncaseous, epithelioid and Langhans’ giant cells are at the center, surrounded by lymphocytes, plasma cells, and macrophages.

Question 30

The mechanism of injury in bovine tuberculosis is

Answer 30

death of cells of the monocyte-macrophage system and of all cell populations in the lung and associated regional lymph nodes secondary to granulomatous inflammation and its mediators and degradative enzymes.

Question 31

Mycoplasma bovis causes what illness

Answer 31

Pneumonia

Question 32

Classical swine fever Gross lesions include

Answer 32

a red-blue discoloration of the skin, hydropericardium, hydrothorax, and hydroperitoneum; hemorrhage and necrosis of the palatine tonsil; and petechial and ecchymotic hemorrhages in most organs of the body, especially the kidney.

Question 33

Female reproductive system brucellosis Gross lesions include

Answer 33

aborted fetuses; necrosis, inflammation, and fibrinoid exudation of uterine caruncles and fetal cotyledons; and a yellow-white uterine exudate.

Question 34

Equine infectious anemia Gross lesions include

Answer 34

an enlarged spleen (splenomegaly) and lymph nodes (lymphadenomegaly) with abundant white-gray lymphoid tissue arranged in follicles and solid sheets of cells that often bulge from cut surfaces.

Question 35

enamel hypoplasia can be caused by?

Answer 35

viral diseases at a young age e.g. distemper virus in puppies

Question 36

Actinomycosis causative agent

Answer 36

the bacterium called Actinomyces bovis

Question 37

Aspergillosis mechanism of injury is

Answer 37

disruption and death of mucosae in the nasal cavity and respiratory system caused by inflammation, its mediators and degradative enzymes, and concurrent proliferation and invasion of fungal hyphae.

Question 38

Aspergillosis

Answer 38

Gross lesions include acute pseudomembranous rhinitis and sinusitis with extensive gray-black pseudomembrane consisting of desquamated epithelial cells, fibrin, and fungal hyphae covering the mucosal surfaces of turbinates, sinuses, and airways or forming granulomas in the lungs.

The underlying bone and cartilage may become necrotic as hyphae invade these tissues.