Which of the Clostriudium species is not histotoxic?
It causes GI symptoms- OVER USE OF CLINDAMYCIN and LYCOMYCIN in horses
increased number of cells in the CSF
What is the best method of diagnosing infections cause by hisotoxic Clostridia?
Direct Fluorescent antibody staining test (DFA); practical and faster option with muscle
Available for C. chauvoei, C. septicum, C. novyi
Anaerobic culture not very rewarding and time consuming
If you suspect a bacterial infection in the nervous system, how would you confirm it?
In you knowledge which of the following bacteria does not have a predilection for nervous tissue?
A. Cryptococcus neoformans
B. Histophilus somni
C. Listeria monocytogenes
D. Bacillus anthracis
cryptocococcus- NS in cats
H. somni- cattle( also causes pneunmonia)
Listeria- ruminants; gets there through trigeminal nerve
Bacterial infections of the nervous system manifests as
Can be manifested as meningitis, encephalitis, Encephalomyelitis
what is special about the drugs that you choose for nervous system bacterial infections?
• Broad-spectrum antibacterials that can penetrate the blood- brain barrier should be selected in treating infections
• Bactericidal drugs are preferred over bacteriostatic agents.
• Higher than normal dosages needed to maintain adequate concentrations in the CNS.
Thromboembolic meningoencephalitis – (TEME)
or Thrombotic meningoencephalitis(TME)
• Histophilus somni
• Occurs 1-2 week after the episode of pneumonia
• Blindness, ataxia, convulsions, depression and coma
• Usually death in 12 hours
What is the pathognomic lesion for H. somni?
Pathognomonic lesions of H. somni infection
Multiple reddish necrotic foci, thrombi in blood vessels composed of leukocytes, fibrin, bacteria-
What happens physiologically in TGE?
The bacteria adhere to the endothelial cells, causing vasculitis, thrombosis, and infarction and continue replicating in the thrombus, triggering an inflammatory response.
Apoptosis of endothelial cells
Host inflammation due in part to the presence of endotoxin and the activation of the coagulation cascade
• Recruitment of polymorphonuclear leukocytes and macrophages to sites of infection
Common infection in cattle, sheep, and goats
Usually occurs after ingestion of contaminated silage during winter time
Encephalitis: Most common presentation in ruminants (cattle, sheep, goat).
Bacteria invade through oral mucosa travels along trigeminal nerve and have affinity for brain stem
Unilateral signs of trigeminal and facial paralysis
In septicemic listeriosis, in calves that die when <3 wk old, Focal hepatic necrosis, and hemorrhagic gastroenteritis are common- NECROTIZING HEPATITIS
A serious food safety pathogen
What is the best tissue to send for culture for Listeria?
How do you diagnosis Listeria?
Listeria enrichment culture or PCR
What is the treatment for Listeria?
L monocytogenes is susceptible to penicillin (the drug of choice), ceftiofur, erythromycin, and trimethoprim/sulfonamide.
High doses are required because of the difficulty in achieving minimum bactericidal concentrations in the brain.
Sporadic bovine encephalomyelitis in Feedlot cattle:
Meningitis in calves as a result of systemic infection by Salmonella Dublin
What is a common infection in cats that causes nervous system lesions?
Cryptococcal infection in cats
Focal symmetrical encephalomalacia
Clostridium perfringens type D enterotoxemia in sheep
Symmetrical necrosis and haemorrhage of the white matter
Clostridium chauvoei (Black leg)
in lab animals and horses
in cattle in the rumen
abysesses in all of the internal organs
espesically after pneumonia
causes abysess in the heart, liver, and other
also causes myocarditis
Edema disease in Weaned pigs
Edema disease in pigs
is primarily a disease of the vasculature, subcutaneous edema
Edema in the, eyelid, submucosa of the stomach, mesocolon
Stress, change of diet, leads to replication of bacteria, toxin absorption, action on endothelium Inhibit protein synthesis by interacting with 60s ribosomes
Microscopically, a degenerative angiopathy affecting arteries and arterioles and necrosis of the smooth muscle cells in the tunica media are present
Traumatic reticulopericarditis(multiple bacteria)
mainly due to trauma
These are pathoneumotic signs for...
Shigatoxigenic E. coli
Edema disease in weaned pigs
What are two disease that cause lymphadenitis?
Caseous lymphadenits (cornebacterium psuedotuberculosis
Strangles(Strep, equi equi)
What are three bacteria that cause Lymphangitis?
-Pigeon fever A different biotype of Corynebacterium pseudotuberculosis
-Sporothrix schenkii-(cats, dogs, and horses- cutaneous lymphgitis)
-Epizootic lymphangitis- Histoplasma farci
Colonizes vascular endothelium causing hemorrage throughout the body
Typhus group; R. prowazekii and R. typhi
Spotted fever group;
Spotted fever group; R rickettsii- (Dermacenter) Dogs may serve as excellent sentinels of risk
R. felis is an emerging zoonotic infection
rodent reservoirs (rats, mice) and an endemic cycle between opossums and domestic cats and infected fleas.
TRANSMITTED BY FLEAS
Rickettsia/ Ehrlichia/Anaplasma/hemotrophic mycoplasma
• Vascular endothelial damage and thrombocytopenia development of petechiae and echymoses.
Necrosis of the extremities (acryl gangrene) or disseminated intravascular coagulation can develop in severely affected dogs.
Require intermediate tick vector for transmission( except R. felis which needs fleas and Coxiella, which can be directly transmitted)
Dogs and other infected animals do not pose a direct transmission risk in normal circumstances.
What is one interesting thing about Coxiella?
It is resisitant to pasturization temperature.
Rickettsia/ Ehrlichia/Anaplasma/hemotrophic mycoplasma
E.chaffeensis-Human monocytic ehrlichiosis,(Humans Dogs) Amblyoma, Dermacenter
E.ewingii- Canine granulocytic ehrlichiosis (dogs and humans)
E.canis- Canine monocytic ehrlichiosis (dogs, humans?)
E.ruminantium- endothelium granulocytes (ruminants) heartwater, amblyoma
A. phagocytophilium- horses, ruminants, humans, dogs; granulocytes Ixodes
A. marginale, A centrale:
A. marginale, A centrale: erythrocytes in ruminants
Anaplasma platys; Dogs; platelets
potomac horse fever
• Anaerobic Gram positive rod
• Spastic paralysis
• Terminal endospores
• Widespread in soil and feces
• Grow in contaminated wounds
• Produce a potent neurotoxin (tetanospasmin)
• AB toxin with zinc endopeptidase activity
Diverse group of organism (Toxin types A-G)
Botulism- Flacid paralysis
Food intoxication (food poisoning)
Toxin absorbed and distributed in bloodstream
Occasional toxico-infectious forms – wounds, intestinal (infant botulism/shaker foal- in unpasterized honey)
Inhibits neurotransmitter release (acetylcholine)
Aquatic life cycle of C. botulinium
Malignant edema(through wounds), Braxy(abomasitis),
Necrotic dermatitis (chicken)
Clostridium species frequently associated with necrotic myositis (Histotoxic Clostridia)
Endospores (widely distributed in soil/GI tract)
Rapid growth in anaerobic conditions fermentative/proteolytic activities
Invasive infections Myositis
Cellulitis, necrotic myositis
Often moves along fascial planes
Lesions appear hemorrhagic (edematous or dry)
May detect gas and crepitus
Sudden death common
Clinical signs may include: fever, anorexia, depression, lameness