Department of Pathology Department of Pathology Faculty of veterinary medicine Faculty of veterinary medicine

- Salmonella can be found in the feces of some infected animals. If people are handling their pet and/or the pet's feces they can get the salmonella on their hands and then inadvertently touch around their face or mouth, and get this salmonella into their mouths. Therefore, good hand washing techniques are imperative after handling any animal.

Definition :- it is infectious disease affecting different species including man and animal. characterized by :- 1- septicemia. 2- enterocolitis & gastroenteritis.

Cause :- Gram –ve m.o serotypes. Predisposing factors of the disease :- 1- Stress factors ( transportations - starvation - parturition – over crowding – aging & antibiotics ). 2- young animals mostly susceptible to septicemic form. 3- adults are mostly carriers.

- This m.o.by ingestion in contaminated food and water  break the enterocytes  lamina propria  inflammation  macrophages engulf salmonella and carry it to lymph vessels  mesenteric lymph node.

-In young : Reach the blood stream through the thoracic duct and cause septicemia “ fatal “. -In adult : Reach the blood stream and cause transient bacteremia  localization in liver, Spleen, gall bladder.

Septicemia : presence of the m.o. in the blood stream with secretion of toxins,,, Salmonella secrets : 1- cytotoxin which cause degeneration and necrosis of enterocytes. 2- endotoxin which cause vascular damage and thrombosis.

1-septicemic form. 2-acute or enteric form. 3-chronic form.

1-fibrinohemorrhagic. 2-septicaemia. 3-Abortion &death of ewes.

Hemorrhagic diarrhea

2-Acute or enteric form :-  Mostly occurred in older animals.  Fever and diarrhea followed by recovery.

1-septicemic cases :- Petechial hemorrhage on serous membrane. Grossly :- 2-In acute cases :- Fibrinohemorrhagic typhlocolitis.

3-in chronic cases :- Fibrinous and ulcerative typhlocolitis.

Microscopically :- 1-fibrino-hemorrhagic enteritis. 2-fibrin thrombi in capillaries of the lamina propria & infiltration with inflammatory cells. 3-edema and congestion of submucosa.

Grossly : 1- Gastroenteritis ( cattarrhal - hemorrhagic or fibrinous ). 2- enlargement of mesenteric lymph nodes. 3- the lesion is more severe in ileum, jejunum and colon.

Microscopically : 1- fibrinonecrotic enteritis. 2- thrombosis in peripheral capillaries. 3- necrosis in payer’s patches.

Liver and spleen : Are not affected in peracute septicemic cases. 1- Liver contained minute foci of necrosis( coagulative ) Surrounded with macrophages and this called(para typhoid nodules)pathognomonic lesion.

Paratyphoid nodules

2- fibrinous cholecystitis. 3- paratyphoid nodules also present in kidney, lymph nodes and bone marrow. 4- spleen contain necrotic foci. 5- in chronic cases, bronchopneumonia, Purulent synovitis.

N.B Salmonellosis is an important cause of abortion in cattle. In majority of cases the abortion is not associated with disease in the dam.