Testing of cats: FIP - PCR test of FCoV
Related tests
- FeLV + FIV + FCoV - PCR tests 3 PCR tests from one sample
FIP - Feline Infectious Peritotinidis
For PCR testing, samples of blood (in EDTA tube) or swabs of rectum are taken. Laboratory provides a cotton swab for mucosae sampling if the customer needs.
Feline coronavirus (FcoV)
Feline coronavirus (FCoV) belongs to the family Coronaviridae of the order Nidovirales. It is a large RNA virus with a genome size of 27 - 32 kb. The viral genome encodes a replicase polyprotein, four structural proteins and several non-structural proteins. According to the genome and antigenic properties it belongs to the coronavirus group I. FCoV is subdivided into type I, with the highest prevalence worldwide, and type II formed by combination of FCoV type I and canine coronavirus. Both types of FCoV can cause a form of a biotype connected with serious disease designated as feline infectious peritonitidis, which is incurable at the present state of knowledge (FIP).
FIP spread
Feline coronavirus has a cosmopolite distribution in domestic cat (Felis catus) and its presence was found in a number of wild felines, incl. lion, panther, leopard, cheetah, lynx, serval and wildcat. In multi-cat environments, such as shelters, all animals tested can be seropositive, while in animals living or bred separately or in pairs is the prevalence substantially lower. Kittens in breeding catteries get usually infected in the age of 5 - 6 weeks (upon fall of maternal antibody levels); however they can be infected any time later in the life. The infected animals begin to excrete the virus, which lasts days or months, in some animals even over the whole life (virus carriers).
Upon coming into contact with FCoV, the most animals show only moderate signs of enteritis. The viral biotype causing enteritis is designated as enteric coronarovirus (FECV). Approximately in 12 % of FCoV-infected cats, the FECV biotype converts to virulent biotype due to accumulation of random mutations during virus replication and develops lethal disease FIP. Approximately 70% of the cases occur within 1 year of age. The biotype connected with FIP is designed as a virus of feline infectious peritonitis (FIPV).
FIP types
From pathogenic point of view, FIP is a granulomatous vasculitis leading to two forms of disease:
1. wet (effusive) form - is characterized by alterations in the abdominal and chest cavities, which result in accumulation of fluids in both body cavities.
2. dry (non-effusive) form - the organism "fights" the virus and responses by production of purulent lesions in internal organs (liver, spleen, intestines, kidney). It is more difficult to diagnose this form, it escapes the attention and the cat often dies without finding out that the cat died from FIP.
The disease form depends probably on the strength of the immune response of the macro-organism mediated by T-lymphocytes, the only thing that can hinder the progression of the disease. In symptomatic carriers, the viral replication is limited to intestine; in animals with FIP, the virus replicates actively even in monocytes and can be identified in many internal organs. Animals with prevalent humoral type of immune response convert easier to FIP.
Treatment and diagnostics
The developed FIP is a lethal disease and today there is no effective causal treatment available. The methods used have only a supportive effect. The FIP prevention by active immunization (vaccination) is disputable (success 0 - 75 %).
Therefore, at present the attention is focused on early diagnostics of FCoV carriers, conversion to FIP and associated epizootologic measures. FCoV-carrier diagnostics is not difficult; however the cultivations methods are very costly and serological methods can be difficult to interpret. Today, several haematological, biochemical and serological tests with limited sensitivity and often with very low specificity are used in addition to a clinical examination (it was stated that more animals were euthanized on the basis of the presence of FCoV antibodies than animals that died of FIP).
References:
Kezban Can-Sahna et al.; The detection of feline coronaviruses in blood
sampes from cats by mRNA RT-PCR; Journal of Feline Medicine and Surgery;
2007
Niels C Pedersen; A review of feline infectious pwritonitis virus infection: 1963-2008; Journal of Feline Medicine and Surgery; 2009
Fermin A. Simons et al.; A mRNA PCR for the diagnostic of feline infectious peritonitis; Journal of virological methods; 2005