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  Discussion on R equi in young foals
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Member:
Lisab

Posted on Wednesday, May 21, 2003 - 11:03 am:

Hi Dr O,

I'm caring for two foals that both got sick about 11 days ago. One is now 2 weeks old, the other 6 weeks. They were stalled at opposite corners of the barn, but prior to the birth of the new one, the mares were turned out together each day.

The initial symptoms were the same for both foals: diarrhea and slight fever (102-103). The older one also had a slight cough, mostly when eating or nursing. The vet had me put both of them on Tribrissen; the younger foal seemed to respond to that initially, but after 2 days his temp went back up, and the older one didn't respond at all. We then put them on Naxcel, but they didn't respond to that, either. The older foal's temp was getting into the 105.5 range, when I'd give him a little bute to bring it down. The vet also had them getting electrolytes to combat the dehydration, and when they weren't nursing enough, I'd also milk the mares and hand feed them.

The older one's symptoms started to get worse, and look like rhodococcus, so the vet ordered erythromycin & rifampin, and we continued with the Naxcel & added gentocin. The younger foal did have some response to the drugs, his temp seemed slightly down, but he'd developed swelling & heat in one fetlock, which progressed (over the course of the next 24 hours) up to his hock, and a few days later, another fetlock was also swollen. He's also very tender on those legs, and doesn't want to put much weight on them, although they're not very sore on palpation.

Both colts started on the erythromycin/rifampin 4 days ago and are being kept in the shade. The older one has had a more or less typical response, from what I've read - his temp will spike up in the afternoon, and we're using various means of bringing it down (hosing down, mister & fan in stall, bute if necessary). He also has mild diarrhea, and is getting electrolytes, and hand fed milk if he doesn't nurse enough. He seems to do fairly well if his temp stays down, otherwise his appetite is poor. This morning he ate grain with mama for the first time in about a week. My biggest concern is that he's developed a reddish brown cloud over the lower part of the iris of each eye, and above that the color is no longer the almost black it should be, but has more of a greenish tinge. His eyes have seemed sensitive to light, and he's kept them mostly closed for the past couple of days, but this morning they were wide open. The problem is that he doesn't blink when I wave my hand in front of them.

The younger colt also has mild diarrhea, but his temp has come down to almost normal, and only goes up to 103.3 or so in the afternoons when it's hot (we're in central Texas). However, his joints are just as swollen & hot as ever. We've wondered if he could have joint ill, but the vet's worried about the rhodococcus settling in the joints, which I can't find much information on.

I've talked to a few people who've dealt with rhodococcus, and they question it because of the age of the foals, which is why we initially didn't think it was, until they didn't respond to the other antibiotics.

(I'm sorry this is so long; just wanted to give you the background before asking questions.)

My questions are these:

1) Do you have any ideas about the eye trouble on the one foal? I can't find any info on that being a possible side effect of either R. equi or the medication.

2) How early is it possible for foals to get a rhodococcus infection? I know these two are much younger than average, but is it still a possibility?

3) What about the swollen joints on the young foal? If it's infection, how long should it take to respond to the antibiotics?

Any ideas you have would be welcome!

Thanks, Lisa
Moderator:
DrO

Posted on Wednesday, May 21, 2003 - 10:22 pm:

Hello Lisa,
1) It is probably not related to either.
2) Rhodococcus is a very common soil contaminant, see article on Rhodococus for more on this. I have seen foals as young as 21 days die from a peracute pneumonia where R. equi was isolated from the abscesses in the lungs.
3) This question is not really answerable:
a) what if the infection it is not sensitive to antibiotics you are using? I would be concerned if there was not improvement in 24 to 48 hours.
b) Antibiotics alone are not appropriate therapy. See the article on septic arthritis for more on this.

DrO
Member:
Lisab

Posted on Thursday, May 22, 2003 - 11:45 am:

Thanks, DrO,

I'm now concerned that the eye problem is uveitis and it's just red/brown instead of white because of the rifampin. Does that sound possible?

Thanks for the confirmation on the age thing.

I'm also concerned that the joint inflammation is caused by septicemia (the younger foal is pretty classic for that, so I suspect that over R. equi) and he needs to have those joints flushed in order to recover. I haven't read your article yet, but will look for it now. Also try to talk the owner into another vet call.

Thanks again, Lisa
Moderator:
DrO

Posted on Thursday, May 22, 2003 - 4:56 pm:

Lisa the eye problem does not sound like typical uveitis, perhaps bleeding into the anterior chamber? I can only guess that trauma might be the cause.

Though I have not heard of such a symptom/complication from Requi and its treatment I went and did some research and found that the rifampin can cause the body fluids to turn a orange color. Though it does not describe it as appearing in the eyes, it describes it in the urine and tears: have you seen any other oddly colored fluids or tissues. The literature says this is not harmful. Also it can cause hemolysis, another cause of discolore urine, I have never heard of this discoloring the anterior chamber. This needs to be looked at by a veterinarian quickly and I would like to know what he reports.
DrO
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