Blood transfusion in cats:

Guidelines for minimising risks of infectious iatrogenic complications

Overview:

The availability of blood components has increased the number of indications for transfusing cats, and fresh whole blood is readily accessible to clinicians because it can be taken from in-house donor cats or ‘volunteer’ feline blood donors. A certain amount of risk remains to the recipient cat, as immediate or delayed adverse reactions can occur during or after transfusion, related to immunemediated mechanisms. This article, however, focuses on adverse events caused by infectious agents, which may originate either from contamination of blood following incorrect collection, storage, or transfusion or from transfusion of contaminated blood obtained from an infected donor.



Prevention of blood contamination:

In cats, blood cannot be collected through a closed system; therefore, collecting donor blood requires a multi-step manipulation of syringes and other devices. It is crucial that each step of the procedure is performed under the strictest aseptic conditions and that bacterial contamination of blood bags is prevented, as bacterial endotoxins can cause an immediate febrile reaction or even fatal shock in the recipient cat.



Prevention of disease transmission:

With a view to preventing the transmission of blood-borne infectious diseases, the American College of Veterinary Internal Medicine has adopted basic criteria for selecting pathogens to be tested for in donor pets. The worldwide core screening panel for donor cats includes feline leukaemia virus, feline immunodeficiency virus, Bartonella species, and feline haemoplasma. The list should be adapted to the local epidemiological situation concerning other vector-borne feline infections. The most practical, rapid, and inexpensive measure to reduce transfusion risk is to check the risk profile of donor cats on the basis of a written questionnaire. Blood transfusion can never, however, be considered entirely safe.



The guidelines were published in the Journal of Feline Medicine and Surgery 17 (7), 2015, 588-593 by Maria Grazia Pennisi et al.

Feline parvovirus infection:

Evolution of feline parvovirus (FPV) and canine parvovirus (CPV)

Feline parvovirus (FPV) is a highly contagious pathogen of cats. It is also known as feline panleukopenia virus and feline infectious enteritis. FPV can be seen in any age of the cat, but infection is most common in kittens and adolescent cats, as their maternally derived antibodies (MDA) wane, and they encounter the virus for the first time.



Feline parvovirus infection is probably the greatest major disease threat to any rescue facility and infection carries a very high mortality rate, particularly in unvaccinated kittens. Parvoviruses can survive for long periods (up to several years) in the environment and are resistant to many disinfectants. It is spread by direct fecal–oral contact and indirectly following contamination of the environment or objects. Cats infected with feline parvovirus can continue to excrete the virus for a variable period, which may be several weeks following infection. Dogs can also transmit the virus.



Clinical signs

Although in some cases the clinical presentation can be similar to the closely related CPV, which is characterized by lethargy, vomiting, and diarrhea, there appears to be a wider range of possible presentations seen in cats. Some cats will initially present as lethargic, inappetent, and pyrexic for some time before vomiting or diarrhea. Dribbling owing to nausea can be seen. Cases of sudden death are seen relatively commonly, where an apparently healthy cat is found dead or dying, usually due to peracute sepsis secondary to the damage FPV has inflicted on the gut.



Treatment and Prevention

Fluid therapy and nursing care are the cornerstones of treatment for infected cats. FPV is a challenging disease to manage. Its ability to spread quickly and cause very high mortality rates means that a strong emphasis on prevention is key, especially in a shelter or other multi-cat environment. Treatment of affected animals and control of spread is challenging and will be most successful if an outbreak is identified early and strong measures are implemented quickly and decisively. Vaccination is a useful component in protection, and population-based vaccine strategies should be considered when the risk of disease is high. Parvovirus vaccines are highly effective, and their cost-benefit ratio is excellent when the disease's direct and indirect costs are considered. With these measures in place, hopefully, it should be possible to minimize cases of this devastating and very preventable disease.

Diagnosis:

Wherever a clinical suspicion of FPV exists, patient-side tests are usually the first port of call. They vary in their exact method of action, but they all fundamentally detect parvovirus antigens in the feces. Diagnosis is frequently made with immunofluorescence assays to detect FPV infection. Bioguard’s FPV Ag Test is a sandwich lateral flow immunochromatographic assay self-developed and manufactured for the rapid and qualitative detection of FPV antigens in cats.