Ruminant and Camelid Diarrhea Differential Diagnoses Flashcards
describe salmonella
background:
1. similar to horses BUT
2. host adapted (endemic) serotype in cattle: salmonella dublin
3. additional common serotypes: S. typhimurium, S. cerro, S. montivedo, S. heidelberg, S. newport
clinical findings:
1. similar to horses, wide spectrum of disease possible
2. complications of endotoxemia/SIRS seems less likely in ruminants, but still very possible
diagnosis:
1. fecal culture or PCR: repeated or pooled samples
2. rectal biopsy culture/mesenteric LN culture
3. serology (ELISA): salmonella Dublin
-diff from horses!
prognosis:
1. variable like in horses, but rum have better prognosis overall
2. ZOONOTIC and REPORTABLE in GA
3. cattle vaccines DO exist, questionable efficacy
describe C. perfringens
- anaerobic gram positive rod-shaped bacteria
-present in environment and part of normal microbiota
-presence DOES NOT equal disease - RARE cause of diarrhea in adult ruminants overall
-more common in neonates/juveniles - biotypes based on toxin production
describe diagnosis and prognosis of C. perfringens
diagnosis:
1. isolation of C. perfringens alone does NOT = diagnosis
2. must demonstrate toxin production: fecal ELISA or PCR
prognosis:
1. poor
2. vaccines available: type C and D pretty effective
3. prevent excessive or sudden starch/sugar/digestible protein ingestions
describe bovine coronavirus
- winter dysentery; betacoronavirus
- fecal-oral and respiratory transmission
- outbreaks most common in:
-housed dairy cattle
-wintertime: november-april
-northern states - short incubation
- destroys colonic crypt epithelial cells
describe bovine coronarvirus clinical signs
- fever and mild respiratory signs: sometimes be present before diarrhea
- lethargy
- acute, severe diarrhea +/- blood
- decreased appetite, dehydration possible
- significant drop in milk production
- typically spontaneously resolve within 24-36 hours
describe diagnosis and prognosis of bovine coronavirus
dx: often presumptive, fecal ELISA or PCR
prognosis: good to excellent (self resolve), vaccine available but not widely used
control: mgmt and vaccines
describe bovine viral diarrhea virus (BVDV)
- pestivirus
- type biotypes:
-cytopathic
-non-cytopathic - two genotypes: type 1 and type 2
- mutates: often and random!
- transmission:
-horizontal: ingestion/inhalation after direct contact, contam vectors, semen, or embryos
-vertical: transplacental
describe BVDV acute infection
- complex spectrum of clinical manifestations
-subclin to severe
-GI, resp, repro, immunosuppression - transient viremia
- transient viral shedding
-duration dependent on strain - subclinical = majority (70%) of infections
-mild fever, leukopenia, decreased milk production - acute clinical disease:
-damage to epithelial surfaces of GI, resp, integument = widespread clinical signs
-hemorrhagic syndrome in most cases: TCP, petechiation and ecchymoses mucosal surfaces, epistaxis, blood diarrhea, bleeding from injection sites/trauma, death
describe BVDV reproductive disease
- infertility/early embryonic death: before and during 1st 60d of gestation
- abortion: typically 60+ days but can be any stage
- persistent infection: from 0-125d of gestation
-non-cytopathic phenotypes only! - congenital defects: from 80-150d of gestation
- acute infection: from 150+ days of gestation through adulthood
describe BVDV persistent infection
- in utero infection at <125d gestation
- immune system does not recognize virus as foreign so does not mount immune response
- always associated with non-cytopathic strains
- mostly poor doers clinically but not all!
- continuously shedding the virus
-major source of infection for everyone else on farm
describe congenital defects associated with BVDV
- CNS: cerebellar hypoplasia, microencephaly, hydrocephalus, hydranencephaly, porencephaly, hypomyelination
- ocular system: cataracts, microopthalmia, retinal degeneration, optic neuritis
- others:
-thymic hypoplasia
-hypotrichosis/alopecia
-deranged osteogenesis
-mandibular brachygnathism
-growth reduction
describe BVDV diagnostics
- virus isolation in cell culture
- antigen detection:
-antigen capture ELISA (ACE)
-IHC
-acute and PI calves - nucleic acid detection
-RT-PCR
-acute and PI calves - antibody detection: serum
-only for acute cases, PI calves never made antibodies
most important aspect for herd surveillance is to detect PI animals!
describe BVDV client education/prognosis
- prognosis variable for acute disease
-dep on severity - grave for mucosal disease
- control/prevention rely on:
-ID and culling PI animals
-biosecurity and surveillance
-vaccination: may reduce severity of signs
describe paratuberculosis (chronic)
- Johne’s disease
-mycobacterium avium subspp. paratuberculosis (MAP) - transmission:
-fecal oral most common
-colostrum or milk
-transplacental - susceptibility to infection is greatest in young animals
- long incubation period:
-infected when young but no clinical signs until older - pathophysiology:
-incites a chronic inflammatory response
-granulomatous inflammation causes intestinal thickening, clubbing of villi, and marked lympahgiectasia which causes maldigestion and PLE
describe paratuberculosis phases of infection
- eclipse phase:
-no shedding
-no clinical signs - asymptomatic shedder phase
-detectable fecal shedding
-spread to extra-intestinal sites can allow for shedding in colostrum, milk, and infection through the placenta - clinical disease phase:
-pipestream diarrhea (cattle only)
-rapid weight loss progressing to emaciation/cachexia
-hypoproteinemia leading to edema: brisket and jaw
-animals typically afebrile and still have very good appetite (until very late in course of disease)
describe paratuberculosis diagnosis and prognosis
- immune-based tests:
-ELISA on serum or milk preferred
-drawback is that infected animals will start fecal shedding prior to producing detectable antibodies - organism detection tests:
-Fecal PCR preferred
-allows earlier detection of fecal shedding!!!
-more expensive though
NOTE: no test works perfectly for screening due to eclipse phase!!
prognosis: grave, control is the focus
describe trichistrongyles
- group of parasites that includes:
-Haemonchus: caprine, ovine, camelids
-ostertagia: bovine
-trichostrongyles
-cooperia
describe haemonchus
- parasitic nematode lives in abomasum
- feeds on blood: anemia and hypoproteinemia
- resulting decreased oncotic pressure leads to intestinal edema and loss of fluid into lumen, sometimes enough to cause secondary diarrhea
- routine FAMACHA scoring, FEC surveillance, judicious use of anthelmintics and ancillary mgmt = important
describe ostertagia
- parasitic nematode in abomasum
- clinical signs:
-difficulty gaining wt or wt loss
-diarrhea
-hypoproteinemia and edema that can lead to diarrhea
-ill thrift - routine FEC surveillance, judicious anthelmintics, ancillary mgmt
describe coccidia
- rare cause of diarrhea in adults unless immunocompromised
- only exception in Eimeria macusaniensis:
-can occur in camelids of any age (as young as 21d)
-risk factors and pathophys similar to other coccidia apart from ability to infect adults and longer prepatent period of 35d
-clinical findings: lethargy, wt loss, diarrhea (+/- bloody), hypoproteinemia without anemia
-dx: fecal float or fecal PCR
-prog: good overall with tx
describe E. coli
- colibacillosis
- may strains:
-ETEC: enterotoxigenic - septicemia
- localized non-enteric (coliform mastitis)
describe pathophysiology of E. coli ETEC
- fimbriae (pili) mediate attachment to cells
- adhesion of bacteria to enterocytes is age dependent
-decreases as calf ages
-primarily affects calves 1-4 d old - enterotoxins produces: cause hypersecretion of fluids and electrolytes (Na, Cl, K, bicarb)
-heat stable toxin
-heat labile toxin
describe clinical signs of E. coli
- severe watery diarrhea: pineapple juice appearance
- lethargy progressing to dullness/stupor/coma
- decreased milk intake
- dehydration progressing to hypovolemia
- tachycardia, hypothermia, acute death
describe diagnosis of E. coli
- bacterial culture
- E. coli pilus antigen ID
-ELISA
-multiplex PCR - histopathology post mortem
describe prognosis and control of E. coli
prognosis variable
control: biosecurity, dam vaccination, calf passive immunization
describe salmonella in calves
- usually calves approx 10d old and older
- can also cause septicemia
- S. dublin and typhimurium most common
describe clostridium in calves
- usually calves less than 2 weeks
- often the healthiest, quickly growing calves, from dams with high milk supply
- type C most common: segmental enteritis
describe rotavirus
- most frequent pathogen isolated from calves with diarrhea
- primarily affects calves 3-21 d old
- fairly short incubation: 15-96 hr
- damages/denudes SI microvilli
-loss of lactase causes maldigestion of lactose and osmotic diarrhea
clinical signs:
1. diarrhea: yellow, watery, voluminous
2. dehydration
3. anorexia
diagnosis:
-ELISA and fecal latex agglutination most common
prognosis: good to guarded, vx avail
describe coronavirus in calves
- affects calves 5-30d
- typically more severe diarrhea than rotavirus
describe cryptosporidium in calves
- cryptosporidium parvum
- second most frequent pathogen in calves with diarrhea
- fecal oral transmission of thick walled oocysts
-very hard in environment - 5-12d incubation period
- colonizes a unique place within enterocyte plasma membrane
-intracellular by extracytoplasmic
-causes villous atrophy and fusion leading to malabsorption
-autoinfection of neighboring enterocytes
describe cryptosporidium clinical signs, diagnosis, and prognosis in calves
clinical signs:
1. most common in 1-4wk old calves
2. anorexia
3. yellow, watery, malodorous diarrhea for 6-1 days
dx:
1. fecal float: sheather’s solution (sucrose); will see small thick walled cryptosporidium
- dried fecal smears: oocysts staining with acid fast stains
prognosis: good to guarded
-ZOONOTIC AND WILL INFECT HUMANS!!!!
-control: good biosecurity, resistant to many disinfectants, requires ammonia or peroxide based products to disinfect
describe coccidia in cattle, small ruminants, and camelids
cattle:
-eimeria bovis and eimeria zuernii most pathogenic
-3-6months of age
small rum:
-eimeria caprina/ovinoidalis most pathogenic
-1-4 months of age
camelids:
-eimeria macusaniensis most pathogenic, E. alpacae, E. lamae
-1-6 months (E. mac can infect adults)
most often associated with changes in feed, weaning stress, and/or overcrowding/confinement
describe coccidia pathophysiology
- 15-20 day prepatent period (except E. mac 35d)
- fecal oral transmission
- replicate within cells, rupturing the cell to be released
-localized primarily to lower ileum, cecum, and LI
describe coccidia clinical signs
- diarrhea +/- blood/mucus
- tenesmus
- anorexia, dehydration, weakness
- chronic subclinical infections can lead to juveniles with ill thrift
- rarely, nervous coccidiosis occurs and leads to neuro signs
-muscle fasciculations, hyperesthesia, nystagmus, tonic-clonic convulsions, ventroflexion of head/neck
describe diagnosis and client education for coccidia
diagnosis:
1. fecal float: large numbers in clinical disease
- McMaster
- modified Stoll
education:
-prognosis is good with treatment
-control/prevention: biosecurity/minimize stress
