FIP - A paradoxical infectious disease

On the subject Infetiöse Feline peritonitis (FIP), I would like an excellent article by Michael Grimm play. At the express request of the article is reproduced here unchanged.

Author: Michael Grimm
Version: 1.1.1
Last revision: 06.06.2007
Original version: http://www.odo.in-berlin.de/mini-FIP-FAQ.html

Copyright © 2002-2007 by Michael Grimm

This text may only be used in unmodified form, and only with a clear reference to the original version http://www.odo.in-berlin.de/mini-FIP-FAQ.html for their own websites to be!

This text has emerged as the Feline infectious peritonitis (FIP) in the news group de.rec.tiere.katzen frequently discussed, and it always comes back to misunderstandings. Therefore, I would try to shed some light on this unusual disease to bring.

Unless otherwise indicated, the following is based on two text books of veterinary medicine [1,2] and a dissertation [3].

I would like to point out that I am not a trained veterinarian and me in this text above facts by the study of literature had appropriated. This text is by no means complete, and also he can be no proper guidance and supervision by a veterinarian or a veterinarian replace. I take no responsibility for the accuracy of the information.

Introduction

The feline infectious peritonitis is an infectious disease which is not sure it can be shown before the lack of a reliable protection, and for which no treatment options are known. It always leads to the death of the cat. The most common disease of young cats between six months and two years and older animals from the age of 14.

There are two different forms, the dry and wet FIP FIP. The latter is because of the inflamed abdominal skin, heart and chest fur bag to massive effusions in the body cavities. This leads to the typical "water belly" (see Figure 1 in [4]). In the dry form remain fluid secretions of infected organs. However, also mixed forms of both forms of FIP observed.

The disease symptoms at the onset of wet FIP are manifold: Most refused to cat food, and provides magert obviously sickly. Then it comes to a sharp increase in abdominal circumference, and requires a fever. The dry FIP is less clear symptoms accompanied Here are loss of appetite and weight loss. In addition, you often anemia, jaundice and sometimes problems with the eyes and the nervous system.

How does an FIP?

It is for the understanding of the following text extremely important to einzuprägen following facts: There are two almost identical corona virus in the cat: the completely harmless feline enteric coronavirus (FECV), and from this through mutation resulting malignant FIP virus (FIPV). Both viruses are genetically so closely related that it is only through very complex molecular biological methods to keep apart. That is why we also summarizes both viruses to the feline corona virus (FCoV) together.

The FECV can be everywhere and in large numbers in the environment for you, which is why so many cats are infected. The recording is done by mouth or nose in contact with infected feces or FECV-contaminated items. Even the man can carry the virus and transmitted to the cat [5]. Common virus infecting cats mothers carrying their pups.

Most of the cat owner gets from the FECV initial infection with nothing, sometimes he can observe a slight diarrhea. The FECV multiplies in the intestine and is there by the immune system effectively combated with antibodies. Only in a few cases it comes to a complete elimination of FECV; mostly remain virus and antibody-existent in the body and hold the balance. Very few cats FECV distinguished the long-term or even permanently with their droppings from.

As already mentioned, the FECV multiply in the gut. Here, there are often mutations [6], but very few of these mutations are also dangerous, and only those which enable the virus, called Freßzellen the immune system (macrophages) to infect. These mutants are the so-called FIP virus. They are still corona virus, but now the once aggressive variants FECV harmless.

We now know that these mutant FIPV for the disease FIP responsibility. What mechanisms ultimately to the outbreak of FIP, is still not entirely clear. The currently available scientific findings point out the following scenario:

A physically healthy cat FECV reacts after an infection with a functioning immune response that the infected Freßzellen (macrophages) at bay to hold the interview. In a small, socially stable cat population is this cat very many years and probably never live to FIP cancer.

It comes to problems with disruptions of this balance, whether by stress in large cat populations, whether through illness, which weaken the immune system directly (FIV or "leukosis"), either by moving into a new environment or stress after surgery. Due to the weakened immune system may be FECV Now multiply. This increases both the number of proliferation-related mutations, which in turn requires the formation of dangerous FIPV mutants more likely, and these can now be undisturbed in the Freßzellen (macrophages) to leave the intestine and is spread throughout the body.

This means that the deadly disease FIP its course. It is currently involved in that in a not entirely immune system collapsed the dry FIP trains, while a zusammengebrochenes totally immune to the wet form leads.

In summary noted: A cat is not inifziert with FIPV but with FECV. FIPV arise by mutation in the cat. They are only dangerous if a weakened immune system can not prevent that they can multiply and leave the intestine.

In addition, a genetic predisposition to the formation of a FIP discussed, that is, it could be that some cats hereditary susceptibility to FIP than others.

Can FIP evidence?

There is one in connection with FIP widespread misunderstanding, and that concerns the "FIP titres. A titer is a measure of the quantity of antibodies in the blood. The higher the titer, the more antibodies were found. A titre of 1:10.000 means that the blood sample to the 10,000-fold had to be diluted before the antibodies no longer be demonstrated. Thus, a titer of 1:10 significantly less antibody in their blood than a titer of 1:10.000.

With the previously described causes of the disease FIP is immediately apparent what the misunderstanding is: There can be no "FIP titres" that it can only give a titre of antibody against the harmless FECV attaches. The FIP-titer "should therefore be properly coronavirus titres respectively. Unfortunately, the persistent and erroneous name seduced again and again to the false conclusion, a high titer was almost synonymous with the FIP.

But what can be a positive titer really show?

1. The cat is just a harmless infection by FECV.
2. The cat has even a sometime FECV infection through and / or contribute FECV harmless in itself.
3. The cat has been vaccinated with Primucell ® (see below).
4. The cat has an acute FIP.

A positive titer may therefore have a number of innocent reasons. In addition, cats that even with a negative titer, ie without any antibodies in the blood of acutely ill FIP can be. This should be clear how weak the titer actually is.

It is currently researching increasingly clear methods for detection of mutant FIPV. Because of the very great similarity to the harmless FECV designed this to be extremely difficult. Both based on the virus itself as well as on the basis of the antibodies it is not yet verified method, both viruses clearly demonstrate or to differentiate.

Furthermore, they are trying to use a so-called FIP-profile, ie on the basis of various blood parameters, a ausgebrochene FIP evidence. Unfortunately, this also allows profile no clear diagnosis.

Even with a wet FIP conducted a diagnosis can not with absolute safety. While there are methods for the examination of fluid samples from the abdominal cavity, the diagnosis very likely. One hundred percent sure they were not.

Conclusion: There is currently no clear evidence of FIP disease.

Can a cat against FIP protect?

Under the scenario described above, to the emergence of a FIP, it is understandable that a vaccine aimed at must be infected with the harmless FECV be prevented.

Initially believed that such protection is usually triggered by the antibodies in the blood can build up. Unfortunately accelerated but was the antibody in a subsequent infection of an outbreak of FIP [7].

Since 1991, a vaccination against FIP on the market, which should avoid this complication. The vaccine is Primucell ®, is supported by the Pfizer manufactures and directly into the nose of the cat geträufelt. This vaccine is a manipulated FIPV strain used only when the temperatures around 31 ° C may increase, but not in normal body temperature of the cat of 39 ° C. With this trick you want to prevent the FIPV of vaccine in the body, there is increased and thus can have bad consequences.

It is thus only one antibody formation in the main entrance gates of FCoV be: in the mucous membranes of the nose, mouth and pharynx. These antibodies will be purely local effect and not in the blood circulation, which unfortunately still happens occasionally, and thus a measurable coronavirus titres leads.

The effectiveness of this vaccine is in the professional world extremely controversial. Broadly, there is agreement that only a vaccine for cats to be recommended, which has never been in contact with Corona virus had. But even then, the protective effect at much less than 100 percent.

FIP is especially in larger herds cats a problem, that is, in animal shelters and cat breeds, as there is much more cats with corona virus had contact than in cats in single stance without Freigang the case.

Especially for a cat breeds Frühabsetz program developed [8], which is essentially based on cats puppies after the sixth week of life of their mother to be separated, so the date on which they are protected by the milk lose. The puppies will be up to its duty in the 16th Living week, but isolated from all adult animals kept. This can be infected with viruses by Corona adult cats successfully avoided. A large-scale study has shown that even a vaccine with such Primucell ® puppies aged between nine and twelve weeks no protection against infection with corona virus could guarantee [9].

FCoV be on the faeces. Because they are dried feces for several weeks can survive, is a fastidious cat hygiene protection a good possibility.

Could FIP diseased cats to other cats with FIPV infected?

This would have the mutant FIPV from cat to cat can be transferred. On the other hand, speak the following two findings:

1. As mentioned above leave the FIPV in Freßzellen (macrophages) the intestine and spread throughout the body. This represents a significant excretion through the feces blocked the main source of infection for FCoV represents.
2. No two cats sick at the same FIPV mutants [4].

Under current state of research is therefore a direct infection of a cat with mutant FIPV excluded.

Literary Quotations

[1] W. Kraft and UM Dürr / K. Hartmann, cat diseases, "Schaper Verlag, Hannover 2003
[2] V. Schmidt / M. Horzinek, "Diseases of the cat, Volume 1 +2", Enke Verlag, Stuttgart 1997
[3] http://elib.tiho-hannover.de/dissertations/liessmannk_2000.pdf
[4] http://www.vetscite.org/issue1/reviews/txt_index_0800.htm
[5] NC Pedersen, in "Virus infections of carnivores, 267 (1987), Elsevier Science Publishers, Amsterdam
[6] The mutation rate is one mutation per 10,000 to 100,000 base pairs. Since the genetic information of FCoV to 30,000 base pairs encoded, it can at any propagation for up to three selection errors, ie mutations come.
[7] This phenomenon is also called antibody dependent enhancement. This means that the vaccine created by the lead antibody in the case of a subsequent infection in a faster and stronger, unfortunately, an outbreak of FIP.
[8] NC Pedersen, Feline. Pract., 23, 108 (1995)
[9] http://www.vetold.unizh.ch/dissertationen/diss_anzeige.php?ID=43&sprache=de