Medicine

• Hemorrhagic septicemia, also known as Hemosep and bovine pneumonic pasteurellosis, is the most economically important bacterial disease of water buffalo and cattle in South East Asia.
• The etiology of Hemorrhagic septicemia is Pasteurella multocida, a gram-negative coccobacillus.
• Hemorrhagic septicemia is classified based on the capsular antigen and a number for the somatic antigen, with serogroups including A, B, D, E or F.
• Serotypes B:2 and E:2 are the most common serotypes of Hemorrhagic septicemia.
• The tonsils of up to 5% of healthy water buffalo and cattle are colonized by small numbers of P multocida serotype B:2 or E:2, which can be shed during periods of stress.
• Hemorrhagic septicemia is an extracellular bacterium and immunity is primarily humoral.
• Endotoxin is a major virulence factor in Hemorrhagic septicemia.
• Hemorrhagic septicemia replicates in the tonsil.
• Transmission of Hemorrhagic septicemia can be through direct or indirect contact, saliva and nasal secretion, and is most prevalent during the rainy season.
• Hemorrhagic septicemia is a stress-related disease and is most often seen in cattle and water buffalo.
• Buffalos are more susceptible than cattle and infection is short course.
• Hemorrhagic septicemia is zoonotic.
• Clinical signs of Hemorrhagic septicemia include high fever, excessive salivation and profuse serous nasal discharge which may become mucopurulent, dyspnea accompanied by frothing at the mouth or nostrils, and edematous swellings in the submandibular up to brisket region.
• Post-mortem findings of Hemorrhagic septicemia include edema, cellulitis and widely distributed hemorrhages, general hyperemia, endotoxin-derived coagulopathy with endothelial damage, and incision of edema on the neck and brisket reveals a straw colored serous fluid, blood tinged fluid in the pericardial sac.
• Some animals may have diarrhea and abdominal pain, or hemorrhagic gastroenteritis.
• In pigs, Hemorrhagic septicemia may involve neurological signs such as tetraparesis, opisthotonos, discolored and necrotic skin lesions in the ventral neck, throat and/or abdomen.
• Pathogenesis of Hemorrhagic septicemia begins in the tonsil and adjacent nasopharyngeal tissues, subsequently, bacteremia leads to disease progression and rapid growth of bacteria in various locations, tissue injury, a host cytokine response, and release of lipopolysaccharides that results in a rapidly progressing endotoxemia.
• Affected muscles are dark red to black and dry and spongy, have a sweetish odor “butyric odor”, and are infiltrated with small bubbles but little edema.
• Clinical signs of Black Disease include sudden death with no well-defined signs, affected animals often being 2 – 4 yr old, lagging behind the flock, and assuming sternal recumbency before death due to abdominal pain caused by hepatitis.
• Swollen Head Disease, also known as Big head, is caused by Clostridium novyi type A and is characterized by a nongaseous, nonhemorrhagic, edematous swelling of the head, face, and neck of young rams.
• Treatment includes Penicillin IM @ daily rate of 4000 - 8000 U/kg for 4 - 5 days, incision of affected skin and muscle to create drainage, and the use of proteolytic enzyme (e.g. streptokinase, streptodornase) should be given locally.
• Post-mortem lesion of Black Disease includes grayish yellow, necrotic foci in the liver along migratory tracks of the young flukes, an enlarged pericardial sac filled with straw-colored fluid and excess fluid in the peritoneal and thoracic cavities, and histologically, the liver lesions include central eosinophilic inflammation (fluke induced) surrounded by coagulation necrosis with an outer rim of neutrophils.
• Diagnosis is done through PCR and FA T (rapid and reliable).
• Black Disease is associated with liver fluke infection and its pathogenesis involves the organism multiplying in areas of liver necrosis caused by migration of liver flukes and producing a powerful necrotizing toxin (α toxin).
• Black Disease, also known as Infectious necrotic hepatitis, is an acute toxemia of sheep that is sometimes seen in cattle and is rare in pigs and horses.
• In some cattle, the lesions are restricted to the myocardium and the diaphragm.
• Treatment for Swollen Head Disease includes broad-spectrum antibiotics or penicillin.
• The carcass of dead animals rapidly decompose and putrefaction and bloating of the carcass occurs quickly after death, causing the leg to extend and spread.
• Lesions develop without any history of wounds, although bruising or excessive exercise may precipitate disease.
• Blood tinged, frothy discharges flow from the body openings.
• Prevention includes a multivalent vaccine (C chauvoei, C septicum and C novyi) and susceptible cattle should be vaccinated and treated prophylactically with penicillin (10,000 IU/kg, IM) to prevent new cases for as long as 14 days.
• Clostridium novyi type B is the causative agent of Black Disease, which is soilborne and present in the intestines and livers of herbivores.
• Leptospirosis is caused by Leptospira serovars hardjo and pomona (major importance in cattle), with serovars Grippotyphosa, Bratislava, Icterohaemorrhagiae, and Canicola occasionally implicated.
• Clinical signs of Brucellosis include abortion in 5th month, metritis, decreased milk production, orchitis, epididymitis, sterility, and potential carrier in bulls.
• Facial and ear paralysis are absent in pregnancy toxemia or ketosis.
• In listeric encephalitis, lesions are confined primarily to the pons, medulla oblongata, and anterior spinal cord.
• Post-mortem findings of Brucellosis include edematous placenta and presence of leathery plaques on the chorions external surface; necrosis of the cotyledons.
• Septicemia followed by localization of infection on the lymph node and genital organ is the etiology of Brucellosis.
• Control of Brucellosis includes vaccination against B abortus.
• There is frequently marked hemorrhagic gastroenteritis in listeriosis.