I’ve written before on the subject of probiotics, bacteria or yeast fed to people or animals with the intent of affecting health in some way. I consider them to be in a bit of a gray zone between mainstream medicine and CAM. There is some plausibility to the underlying idea, and there is some clinical evidence that probiotics can be helpful for GI problems such as antibiotic-associated diarrhea and community acquired diarrhea. However, the wild claims that are sometimes made about probiotics of “boosting the immune system” and treating virtually any disease whether related to the GI tract or not fall into the realm of CAM.
A colleague recently went to a continuing education conference and reported that one of the speakers suggested a particular probiotic product, Fortiflora, can help with symptoms of Herpesvirus rhinitis. Feline herpesvirus 1 (FHV-1) is a ubiquitous viral infection that in some cats can cause chronic, recurrent rhinitis, with sneezing, nasal discharge, and often concommitant conjunctivitis (red, watery eyes). These symptoms come and go, especially with various kinds of stress, and there is no cure and limited benefit from vaccination and oral medications.
I was curious about the evidence for the claim that Fortiflora might help cats with herpesvirus rhinitis since the disease is a common and frustrating one and since the idea that bacteria (specifically Enterococcus faecium) fed to an animal to affect the makeup of the normal GI microflora should help nasal and eye symptoms doesn’t seem to make sense at first glance. My colleague was kind enough to ask the speaker at the conference to send the research paper he had written on the topic, which I reviewed(Lappin MR, Veir, JK, Satyaraj E, Czarnecki-Maulden G. Pilot study to evaluate the effect of oral supplementation of Enterococcus faecium SF68 on cats with latent feline herpesvirus 1. Journal of Feline Medicine and Surgery 2009;11(8):650-4). The experiment was only a small pilot study, and more research on the subject may be warranted, however the existing data do not provide much support for the notion that this product has a role in the treatment of herpesevirus rhinitis.
The study involved 12 cats which had previously been documented to have FHV-1 infection and symptoms of conjunctivitis. The subjects were randomly allocated to a group supplemented with Fortiflora and a control group given an appropriate placebo. They were subjected to stresses such as housing changes and spaying or neutering, and the frequency of clinical symptoms was monitored, as well as measures of GI microflora diversity and PCR to look for shedding of active FHV-1.
Prior to the onset of the study, the cats in the treatment group had a lower rate of conjunctivitis than the control group (13% vs 21%), though this was not statistically significant and might have been due to random chance. There was no significant change in conjunctivitis symptoms for the treatment group during the study (up to 16%), but the placebo group appeared to worsen (up to 29%) which created a significant difference between the groups in symptoms during the treatment period. Of the 6 cats in the supplementation group, conjunctivitis got significantly better in one and significantly worse in another during the treatment period. Of the control cats, one’s symptoms got significantly worse. There was not significant change in symptoms for the remaining 9 of the cats. Respiratory signs were rare in both groups and no differences were measured. With such a small number of cats in the study, it is difficult to view such mixed results as definitively showing or disproving an effect of the treatment on symptoms.
Microbial diversity in the feces (based on PCR) decreased significantly in the placebo group, though there were no significant differences between the level of diversity when the placebo and control groups were compared at any point. Despite some claims of relevance for overall immune function, there is no sound evidence that such measures of diversity represent clinically significant effects on susceptibility to disease. This is typical of studies of probiotics which tend to show that their use does something but which doesn’t tell us what if any real-world significance these effects might have.
Some intermittent shedding of active FHV-1 virus was detected in some cats, but there were no differences between individuals or groups in this measure. There were also no detectable differences in FHV-1 antibody levels or other measures of immune function between groups.
So overall, the study provides little support for the thesis that Fortiflora boosts general immune function in a way that would be clinically useful for cats with FHV-1 rhinitis. Certainly, the additional research the authors suggest is needed may provide greater evidence for this hypothesis, or it may show no meaningful effect. The authors are clearly good scientists, and they are careful in their paper not to make dramatic claims not supported by the data. They tend, as we all do, to interpret the results of their efforts in the most positive light, which is why independent replication of new findings is so important in science. However, the problem with traditional “opinion-based medicine” is to that the theories and opinions of smart and experienced scientists such as these authors are given great weight by those of us in general practice, and there is a tendency to make changes in clinical practices not justified by the quality of the data. This paper is interesting, and the line of inquiry may lead somewhere eventually, but it does not justify the widespread use of Fortiflora for FHV-1 rhintis.
The argument that probiotics “boost the immune system” in general is not a very convincing one, as illustrated in a critique of the concept by Dr.Mark Crislip at Science-Based Medicine. There is no clinical trial evidence that shows resistance to infectious disease can be enhanced in a healthy, normal person. Certainly, white blood cells and inflammatory mediators can react in a variety of ways to all kinds of stimuli, in test tubes and in living organisms. But the connection between these reactions and a meaningful improvement in resistance to disease has yet to be made. Probiotics undoubtedly have some benefits, however the GI microflora and its role in immune function is a dazzlingly complex subject which science is only beginning to understand. Most of the normal organisms present in healthy people and animals have not been identified, and the ecological niche or function of these organisms isn’t known. The effect of tinkering with this complex system without understanding it is ultimately unpredictable, and the assumption that such tinkering must be beneficial is unwarranted. As our basic understanding of the topic improves, I hope targeted probiotic therapies for specific problems will continue to emerge. But at this point, there is little scientific justification for the widespread use of such products for nearly any condition with the assumption of safety and efficacy.
This type of claim seems to be very common in the pet food/supplement industry. I can imagine the sales reps in the mountain west saying something along the lines of “recommended by Dr. Lappin, at Colorado State” since many of us know him from either veterinary school or conferences. It also brings up the issue of corporate sponsorship of veterinary continuing education and how it may influence either the way the speakers present things like this or how we perceive it. It’s nice to pay low prices for CE, but perhaps we are just paying more in other ways.
Yes, it’s a constant problem that vets don’t read the literature or evaluate expert opinions criticallly. The Abstract and Discussion sections frequetly don’t accurately reflect the data, and in referring to a paper such as this one as support for a theory, speakers at CE meetings don’t often add in all the qualifiers and caveats they are careful to include in the paper itself. And sales reps certainly spin the research as favorably as they can. I often ask reps for copies of complete articles they use as support, and again frequently find the artciles don’t support their claims as unequivocably as the reps suggest.
That’s why it’s so important to teach a critical, evidence-based approach to veterinarians, so we can evaluate cliams effectively for ourselves rather than relying solely on expert opinion.
A first CE step should be to get the CE measured as part of the law. Sort of like a state board exam measures the education doctors get. Unmeasured CE laws are just restraint of trade laws quacks use to make unproven medical care the standard of care.
see
http://www.ebvet.com/forum/viewtopic.php?t=405
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While researching ways for me to combat my kitty’s congestion and respiratory issues d/t probably a host of viruses but not FLV b/c she tested neg. I came upon this: https://lactobacto.com/2015/01/12/the-one-probiotic-that-cures-sinusitis/
It’s very compelling to say the least.
Not really compelling, and not related to cats at all. The blog is written by someone with a developmental psychology degree who appears to have concluded she has discovered a miracle,e cure based on personal experience and collecting anecdotes, neither of which is a reliable method for assessing medical therapies. I found two systematic reviews of probiotics in humans for allergic rhinitis (1,2). One seems to conclude there was a consistent benefit, the other concluded that the same data was suggestive but not definitive because of too much variation between studies. And again, none of these are studies in cats. There are few studies of probiotics for URI in cats, and the one I discussed in this post did not provide much evidence of benefit. There hasn’t been any better new evidence since.
This post is from Feb 2010
Has anything changed your opinion on probiotics?
With regard to probiotics for herpesvirus URI in cats specifically, I haven’t seen any new clinical studies that show a benefit, so it’s still a “Who know?” from me.
As for probiotics generally, there is building evidence for several conditions, but overall the underlying problem is still that the microbiome is extremely complicated and poorly characterized, so knowing which organisms in which patients work for which conditions is still really difficult. Worth trying in some cases, particularly GI symptoms, but lots of work to do still before we have confidence consistent recpmmendations for most issues.
I’m struggling to find something to help my cat with herpesvirus. Was told by a vet, new vet to me, that Purina Fortiflora, specifically, was helpful to cats with FHV. I checked it out and it costs $1 per day from Chewy, and quite a bit more from the vets office. I sadly feel skeptical when something is recommended that’s quite expensive and that the vet sells. It seems a lot to pay for something that “might” help.
In past L-lysine was recommended for FHV cats, and I was giving it to my cat for about a year. This same vet told me L-lysine doesn’t do anything. I did some research and found one study claiming that L-lysine supplementation was actually harmful. So now I’m afraid to give that to her.
I also see there is a vaccine that may help, and some places say increased humidity (which I do all winter for her with a vaporizer) and others say nebulization. I would really like to do something because she is having symptoms almost all the time now. It is really hard to know what to do. Do you recommend the vaccine and/or nebulizing?
Vaccination definitely helps reduce the severity of infections and flares when given on a regular basis (AAFP recommends every three years in adult cats). It’s much less clear if vaccination more often or in cats with active symptoms is helpful, so I don’t think that question has a clear answer yet.
Humidification and nebulizing with saline can be helpful to control congestion and make cats more comfortable, though they don’t directly address the infection, of course. For cats with moderate to severe symptoms, it may be worthwhile to use antiviral medications when needed.
As for probiotics, there is one small study suggesting some possible benefit, but the evidence is pretty thin.
Good Luck!