Lecture 12. Infections of the Nervous System 3

what organism causes thrombotic meningoencephalitis (TME)

histophilus somni

what is the etiology of histophilus somni

facultative anaerobic, gram negative, non-motile, coccobacillus

haemophilus spp.

this image indicates what species

what is true of the growth conditions of histophilus somni

1. doesn't require growth factor X or V

2. grows on chocolate agar

3. requires 5-10% CO2

what do colonies of haemophilus spp. appear as when grown on chocolate agar

dewdrop-like colonies

what test is histophilus somni positive for

oxidase

when haemophilus spp. grow around factor V producing bacteria like S. aureus

what is satellitism

what virulence factors are associated with histophilus somni

1. endotoxin

2. phase variation of LOS (induce apoptosis and endothelial cells and leukocytes to evade immune system)

3. transferrin binding proteins (Tbps)

4. IgG binding proteins

5. biofilm formation

septicemia and thrombotic meningoencephalitis in the young are C/s associated w/ histophilus somni in what species

cattle

epididymitis and other repro infections (vulvitis and mastitis) are C/s associated w/ histophilus somni in what species

sheep

how can we Dx. histophilus somni

dry ice specimens on chocolate agar that demonstrate dew-drop colonies in 1-2 days

cattle infected w/ histophilus somni can demonstrate what C/s in the brain that indicate the bacteria

multiple foci of hemorrhagic necrosis

histophilus somni

based on the condition of this cows brain, it was likely suffering from what pathogens

what is the primary way to treat histophilus somni

oxytetracycline

what causes glasser's disease in pigs

glasserela (haemophilus) parasuis

what is the etiology of glasserela (haemophilus) parasuis

facultative anaerobic, gram-negative, non-motile coccobacillus

what growth conditions are needed for glasserela (haemophilus) parasuis

1. requires factor V (NAD)

2. requires 5-10% CO2

3. grows on chocolate or blood agar w/ other bacteria

how are piglets infected w/ glasserela (haemophilus) parasuis

acquire it from sows

what post-moretm conditions is glasserela (haemophilus) parasuis associated with

polyserositis and leptomeningitis

a piglet suffering from anorexia, convulsions, cyanosis, and thickening of pinna is likely infected w/ what organism

glasserela (haemophilus) parasuis

what is the confirmatory method to Dx. glasserela (haemophilus) parasuis

isolation and ID of the bacteria from joint fluid, heart, blood, CSF, or post mortem tissues

how do we treat glasserela (haemophilus) parasuis

antimicrobials such as tetracycline, penicillin, and potentiated sulfonamides

what causes cryptococcosis

cryptococcus neoformans

what is the etiology of cryptococcus neoformans

a capsulated yeast found in the soil

what is cryptococcus neoformans commonly associated with

pigeon excreta

what is comes to the infectivity of cryptococcus neoformans

it is not contagious but is picked up from the environment

the primary site of cryptococcus neoformans infection is

nasal mucosa

what species is most commonly affected by cryptococcus neoformans

cats

how is cryptococcus neoformans transmitted

unencapsulated yeast is inhaled from the environment and capsulates in vivo to avoid immune system

what C/s are associated w/ cryptococcus neoformans in cats

1. nodular skin swellings on the nose bridge

2. distortion of nasal cavity

3. neurologic abnormalities

4. eye disorders (chorioretinitis)

when it comes to the presentation of cryptococcus neoformans in dogs...

disseminated form w/ CNS signs is common

how do we Dx. cryptococcus neoformans

1. C/s

2. smears of exudate or granulomatous tissues

3. culture of biopsy, CSF, or exudate

cryptococcus neoformans

you find these yeast cells on a smear from the nasal discharge of a cat, what might be the cause

Tx. for cryptococcus neoformans

1. surgical-cryotherapy

2. antifungals

what is the zoonotic potential of cryptococcus neoformans

low potential unless immunocompromised

cryptococcosis

this cat is likely suffering from what disease