Posted on Wednesday, September 26, 2001 - 03:00 pm:
Does anyone have experience with foals that, when cultured, grow a corynibacterium bovis? These foals have abnormal lung sounds, some mild mucopurulent nasal discharge, some with slight coughs, normal temperatures, normal fibrinogens and only slightly elevated white counts. They do not seem to respond "normally" to antibiotics, although the sensitivities say they are not resistant to anything. These guys are feeling mostly great. If one didn't listen to their lungs, you would think it was nothing more than normal "cough and snots". These foals are all 2-5 months old, normal IgG's at birth, normal everything else. We have been treating them for ever with Penicillin, Pen & Gen, SMZ's, chloramphenicol, you name it, they've been on it. No abscesses in their lungs, lungs x-ray better then they sound. Pretty sure it's not an allergic type situation (multiple young foals, slightly elevated white counts, snotty noses, and abundant growth of coryni bovis...?).
Any thoughts? Where does coryni bovis come from? This is not the same organism that causes dry land distemper (we've had that, too).
Noble Knight (206.157.249.114)
Posted on Friday, September 28, 2001 - 10:56 am:
Semenfrezr, the Corynebacterium you have encountered is called "Rhodococcus equi" It is found in the soil and transmitted from breathing dust. High amounts of acetic acid (from manure) combined with high heat will grow the bacterium. Most foals will resist lung infections when encountering small amounts of R equi. In your situation, I would consider infection endemic and if left untreated could cause high mortality.
An excellent treatment consists of an antibiotic combination of erythromycin estolate at 25 mg/kg body weight, PO, t.i.d. with rifampin at 10 mg/kg, PO, s.i.d.. Most foals will recover with early treatment. In severe cases, administration of the mares serum at 500 mL to 1L may be beneficial.
The bacteria is quite resistant to disinfectants. Move your foals from infected areas, remove manure, and try to keep the dust down in paddocks and stable.
Wow! We did have a confirmed case of r.equi here, but have only been able to positively culture it on the one foal (it was only the 2nd confirmed case of r.equi in our county). Why do we not see the lung abscesses that I thought were so characteristic of r. equi? Why doesn't my vet (a board certified internal medicinist) know that coryni bovis = r. equi??? We were theorizing that maybe it was something unique to us because we have cattle. I have been almost wanting these to be r. equi because the one that was on erythromycin and rifampin resonded immediately and one that we strongly suspected r. equi on has done very well on just erythromycin. Last year we gave all of the foals the r.equi hyper immune plasma (having never had a confirmed case, but they "act" like it)- and had a higher percentage of sick foals, but none died. We had one die in August that the pathologist originally suspected r. equi on, but the final report came back coryni bovis. Wow! Thanks for your time and ability to shed some light on this.
semenfreezer Knoble Knight is absolutely correct and the reason it is often misdiagnosed is that many veterinarians have little or no first hand knowledge of this condition. Unfortunately slow or misdiagnosis often results in irreversible damage to the foal resulting in death. The key is early and accurate diagnosis and appropriate treatment.
The disease does not respond to typical antibiotic therapy since it is an intercellular organism and thus antibiotics cannot get to it to have any positive effect without the use of a facilitator drug such as Rifampin. It is also very difficult to get a positive culture and even if you do, by the time you get the culture results it may be to late to mount an effective treatment program. Remove as much stress as possible, do not think the foal is out of the woods until the full treatment has been administered. Which is typically at least thirty days.
The best defense if early diagnosis and prompt appropriate treatment. Once you have dealt with a case, the symptoms become very clear and you will probably not miss another one. The most notable symptom is abdominal breathing. Because they have trouble exhaling not inhaling. Years ago we called them pumpers, because thats what it looks like. Short rapid efforts to exhale causing them the contract their abdomen in an attempt to force air out of their lungs.
There have recently been some veterinarians substituting Chloremphenacol as the antibiotic and still using the Rifampin as the facilitator. They have indicated that they get a more profound positive response resulting in a shorter treatment program to recovery. I personally have no experience using this drug in this kind of case. However I have no reason to doubt their findings. The problem with the use of this particular drug is the danger to the humans using it, if it is in pill or powder form. Since breathing or ingesting the dust from this drug has been shown to cause a-plastic anemia in humans in some cases.
One other caution, be sure that the mare does not ingest any of the antibiotics intended for the foal. There have been reported cases of the mares developing colitis-X as a result of this. Again I have never had this happen. But those reporting it, are very capable and knowlegable people.
Best of luck, these cases are never any fun.
HP
Stephanie Campbell (142.21.150.9)
Posted on Wednesday, October 03, 2001 - 10:48 am:
Does this microbe show up in adult horses? I have a gelding who is abdominally breathing (pumping) and occasionally coughing, but has no other symptoms. The paddock he is in is very dusty, and he is on hay.
Stephanie it does show up in older horses but VERY rarely.
HP
Stephanie Campbell (142.21.150.9)
Posted on Thursday, October 04, 2001 - 02:16 pm:
He is healthy except for the breathing patterns. I would assume healthy enough to throw off any normal microbe, especially one that doesn't normally gain footing in an adult horse. I would ask is there are any other blatant possibilities, but this is not a forum of general horse health. Thanks.
Kelly (63.172.47.191)
Posted on Thursday, October 04, 2001 - 02:33 pm:
Stephanie- Aspergillus,Streptococcus and some molds and fungus can affect a hores with symptoms such as coughing, weight loss, exercise intolerance, and decressed immunity.
I use a supplement that helps to eliminate these and other bacteria the may be present in horses. My horses have responded very will to this supplement, and have shown improvement in many areas. This is not a drug, and only effects the negative bacteria present, none of the positive that is needed for a healthy digestive tract. If you are interested, you may contact me a Kellyh@hctc.net for futher information
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