Food Animal Medicine- Diarrheal Diseases of Ruminants 1

pbhati17's version from 2018-02-18 04:23

intro + Johnes

Question Answer
what are the 4 most common diarrheal diseases of the adult rumi?Johne’s Disease, Salmonellosis, Enterotoxemia (C. perfringens), Winter Dysentery (Other Miscellaneous)
what are the 7 most common diarrheal diseases of the neonatal rumi?E coli, Rotavirus, Coronavirus, Salmonellosis, Clostridiosis, Cryptosporidium, Coccidiosis
ACUTE (sudden onset) diarrhea can be split into what two categories?HAS oral lesions or does NOT have oral lesions.
**what are the 4 diseases which cause acute onset diarrhea AND oral lesions?BVDM (mucosal dZ), malignant catarrhal fever, rinderpest, caustic toxins
what are the 9 acute onset diarrhea dzs which do NOT cause oral lesions? (3 emphasized) (easier to remember the YES oral lesion diseases, but still read over)Salmonellosis, Winter Dysentery, Clostridiosis, BVDV (if not mucosal form of the dz, might not have oral lesions), Lymphoma, Ostertagiosis, Endotoxemia (metritis), Plant or metal toxicity, Abrupt diet change
what are 4 things which can cause CHRONIC diarrhea?Johne’s Disease, Parasitism, Chronic Salmonellosis, Lymphoma
Johne’s Disease is caused by what?Mycobacterium avium ssp. paratuberculosis (MAP)
how would you describe johne's (mycobacterium avium ssp paratuberculosis) affects/lesions on the GI?Chronic, granulomatous enteritis--> chronic diarrhea and weightloss
which animals/species are affected by johne's?Affects all ruminants, camelids, cervids
is johne's more prevalent in dairy or beef herds?DAIRY**>beef.
johne's is a dz of MAJOR economic importance, bc..huge eco. loss: Lost production, culling, testing
When are cattle usually infected with johne's? When do you start to see clinical signs?Most infection occurs early in life, but there is a LONG incubation period (2-10 YEARS), so you start to see the dz be expressed clinically around 2-6 years
if you see a 6mo calf and the farmer says "OH NO I CAN'T HAVE JOHNE'S IN MY HERD!!" you are ok to comfort him because...incubation period of johnes (MAP) is 2-10 years so dont start seeing clinical signs until like 2yr age
how would you describe the diarrhea of a johne's case? Progressive watery diarrhea, with NO blood and NO mucus
clinical signs of Johne's?sporatice, progressive watery diarrhea with no blood or mucus, rapid and profound weight loss, edema, and a FAIR TO GOOD APPETITE
how is appetite affected by Johne's?usually fair to good actually.
oh hey there is a 2+ year old cow with rapid weight loss and good appetite. you should prolly look forjohnes
johne's causative agent, MAP (mycobacterium avium paratuberculosis) what is it like (how fast does it grow, how can you cytologically ID it) and where in the body does it like to live specifically?it is slow growing and acid fast. Proliferates in macrophages of distal SI, RLN (regional lymphnodes)
how is the sm int affected by the MAP living there?it causes a Slowly progressive granulomatous enteritis with Thickened corrugated ileal mucosa and regional lymphadenopathy
so if only 1-2 cows are showing signs of johne's, how worried should you be?those are just the tip of the iceburg. If a few are showing signs, There are many more animals infected, and there are There are many more animals shedding. This leads to Subclinical production loss
a rough rule of thumb is that for every 1 clinical case of johnes, there are..20 subclinically affected animals
where does MAP like to hang out and possibly infect cattle?it is very Hardy in the environment and Can survive outside the host 9-18 months!!! It also Survives pasteurization (Probably ubiquitous on affected farms)
when are cattle most susceptible to MAP infection?when they are YOUNG! Susceptibility decreases with age! Increased dose required with increased age, Most cattle are infected as young calves
what are the routes of transmission MAP can take?****#1 is Fecal-oral, can also be Transplacental In advanced stages of disease. It can be shed in milk AND in semen
(pic included) how does MAP infection occur?fecal oral route, so it goes to GI, gets taken up by enterocytes, it goes to the local lymphnodes, which ultimately causes granulomatous inflammation (aggregation of monocytes basically)


Question Answer
what is one reason for how incubation time of MAP varies so greatly? (what makes it faster vs slower)Incubation time decreases with increasing infective dose
explain how johnes is a "spectral" dz ( why is this dz such a problem?)so it is infected, and initially has a Th1 (cell mediated response) and in this response type, Abs aren't made. So we really don't have anyway to detect dz during this whole period (wavy line part) bc there is no Ab response for a serological test. This will persist for years. Then around 2 yr mark, fecal shedding starts to inc. As fecal shedding inc, cell mediated response decreases. So fecal shedding has already started before they begin a Ab response. Then they finally start their Th2/Ab response. Then at max fecal shedding, they finally start to show clinical signs (diarrhea, hypoproteinemia) <img src=""height="250">
what is going on in Stage 1 of infection? (what is MAP doing, how long does the stage last, how does the animal present)This is the stage of the "SILENT INFECTION" where the Organism is incubating in jejunal and ileal mucosa and Eventually spreads to mesenteric lymph nodes. This stage usually lasts a minimum of 2 years and is VIRTUALLY UNDETECTABLE by dx tests (bc no ab response, its all CMI). At this time the animal appear clinical NORMAL
what is going on in Stage 2 of infection? (what is going on with the MAP? how does the animal present?)This is the "Inapparent shedders" stage. The animal is now >2 years old (or has been infected for >2years) and it still has no OVERT clinical signs (might have inc rate of infxns, infertility, and might be culled prior to dx due to production loss). However, they are intermittently fecal shedding. There are even "super shedders" (>1 million CFUs/g manure)
what is going on in Stage 3 of infection? (what is happening to the animal? how long does this stage last?)This is the "clinical dz" stage. The cow will have gradual weight loss, intermittent diarrhea, and dec milk production. However, their appetite DOES remain normal. There is still fecal shedding, but now there IS an Ab response. This stage rarely lasts longer than a few weeks/months
what is going on in Stage 4 of infection? (what are the CS of the cattle, what is fecal shedding like, what is the cow's immune system like, etc)This is the "Advanced clinical disease" stage and cows are severely affected. They are emaciated and have pipestream diarrhea (non-hemorrhagic), and have submandibular edema. The infection is disseminated through the body and there is MASSIVE fecal shedding. There are often very high Ab concentrations, but they can be occasionally anergic (none) because the immune system is exhausted. Eventually the animals die of cachexia and dehydration
guess the stage: clinically normal, cant detect dzstage 1
guess the stage: no overt clinical signs, intermittent fecal sheddingstage 2
guess the stage: antibody response finally presentStage 3
guess the stage: pipestream diarrheastage 4
guess the stage: intermittant diarrheastage 3
(pic) timeline pic for johnes
what is the major clinical sign which is a huge tip-off for johnes?hypoproteinemia (protein losing enteropathy!!)
how do you dx johnes?look for hypoproteinemia, do Bacterial culture of fecal samples, can do DetecLtin of DNA in fecal samples (PCR), Detection of antibodies in serum and milk
3 major CSs of johnes you can make a pretty confident (not definitive) dx off of?Profound weight loss, Pipestream diarrhea, **hypoproteinemia
what is the gold standard definitive dx of johnes, and why is this a difficult thing to do?BACTERIAL CULTURE, but is difficult bc requires a special medium, (need >10CFUs), takes a LONG time to grow (12-16wk). BUT it is Quantifiable (can see if its a super shedder), and is the GS
*In what stages of infecTIon would fecal culture be positive? Stage 2 is when shedding starts
how possible is a false positive from fecal culture?unlikely, can happen if you sample from a cow who ate an infected cows poop and it's just passing through
how good is PCR for DXing johnes?Sensitivity is very good, Faster turnaround time than culture (2-3 days), and still quantifiable
In what stages of infection would fecal PCR be positive?stage 2 is when fecal shedding starts, so stage 2
AnTIbody detecTIon (serology)--> which samples and which tests?Can use blood or milk, ELISA or AGID tests available. High specificity, low sensitivity if clinical signs
In what stages of infecTIon would antibody detecTIon be positive?although fecal shedding starts in stage 2, Ab production doesnt start till stage 3, so can't detect it till then :(
if you want to do Ab detection on a SUBCLINICAL case, what is the best test?ELISA > AGID for subclinical


Question Answer
Herd MAP status classificaTIon is a Government voluntary control programs-- how does it go about checking the environment and the animals?(1) Environmental: Organism detection – 6 congregation areas. (2) Individual animals (#30)-- check cows over 36 mo with ELISA or culture/PCR
When would you treat johne's (As opposed to culling) and what must you do education-wise for these owners?usually considered if Economic, genetic, or emotional value. You will have to Establish a definitive diagnosis and Eliminate animal from the food chain. You must also educate the owner that the tx doesnt really cure, and although CSs will improve, SHEDDING WILL CONTINUE
what is the recc tx?Slaughter or euthanasia is recommended
although there are No drugs approved for treatment in US, what are some ELDU therapies?Isoniazid, Rifampin, Clofazimine, Monensin, Levamisole, Gallium
what are two control points you can try to focus on to dec/elim johnes from the farm?(1) Prevent newborn calves from ingesting manure from adults (2) Culling infected animals to reduce total farm MAP burden
what are some things you can do to try to prevent introduction of MAP in the first place?Acquisition from negative herds only, Avoid auctions/shows, Breed (vs. buy) replacements, Avoid MAP-unknown/positive manure on pastures, crops, equipment, Demand biosecurity enforcement, Document herd status
what are some things you can do to try to prevent NEW infections of MAP (if you couldnt avoid introduction)Cows with clinical disease: cull current and prior year’s calves. You can also separate calves at birth: Maternity pen/calving (dairy), No sick/lame/JD positive cows in group pens, 25 pounds new straw/cow/day; 100 s2/cow, Keep cows clean, Remove calves within 10 min, before standing
explain how you can do colostrum management as a way to help prevent johnesDon’t feed unknown source/status colostrum. Bank from MAP-negative cows (AND DO NOT POOL! use individual containers). Clean teats prior to collection, Heat-treat (140F) for 60 min, Store at 38-40F ≤3 days; then discard/freeze. Colostrum replacer can reduce likelihood of transmission
explain some calf-rearing related MAP prevention strategiesWell separated from adults, Feed milk replacer or pasteurized milk (MAP risk lower (not eliminated) with pasteurized). Sanitation (mixing, delivering) milk/MR critical. Prevent contamination with adult manure (Foot baths, new boots, limit traffic), Don’t’ feed manger sweepings to heifers, Test heifers (org. detection) from high prevalence herds at 7-14 months
what are some more beef cow/calf specific prevention strategies you can do?Separate calving areas for MAP-positive cows, Remove cow-calf pairs quickly, Avoid ponds as a water source, Use test-negative herd sires
(pic) compare the diff control programs for johnes
is there a vx for MAP?yes
what kinda vx is the MAP vx? when do you use this/howIt is a killed vx, but Can ONLY be given with permission from the state veterinarian! It is given to calves under 35 days of age in the Brisket area
so why can the MAP vx only be given to calves UNDER 35d?because they are exposed SO early in life, it is pointless to do it later
advantages vs disadvantages of the MAP vxADVANTAGES: Delays the onset of clinical signs, Reduces and delays the onset of shedding of MAP. DISADVANTAGES: Cross-reacts with M. bovis!! does NOT elim infection. Injection site lesions can develop into severe granulomas
if you use the MAP vx, what should you know about testing for MAP?it will be POSITIVE in serological tests, so you will need to do fecal tests to assess
how does johnes affect small ruimis and camelids?Diarrhea uncommon!!!! (dont really get pipe-stream diarrhea like cattle), they often get "dog like" feces (normally it is pelleted). They WILL get the hypoprotenemia. USE PCR to dx in them
is johnes zoonotic?Link to Crohn’s Disease remains controversial..but johnes IS secreted in milk, and it DOES survive pasturization. Possible consideration with rising chrones rates. MAP does seem to be more frequent in chrone's pts, but MAP can also be found in normal people (Crohn’s presumed to be a multifactorial disease so this makes sense). CAUSATION HAS NOT BEEN PROVEN THO