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A summary of human diseases with similar clinical and histological appearances
J. Beatty1
1University of Sydney, Sydney School of Veterinary Science, Camperdown, Australia
FeLV and FIV in 2018 – Clinical approach and management
Professor Julia Beatty
Sydney School of Veterinary Science, University of Sydney, NSW 2006
Identifying FeLV or FIV infection is important to optimize individual health care and prevent new infections. Serology is the first line diagnostic test and positive results on serology should be confirmed. Interpretation of retrovirus test results requires integration of the clinical findings, patient risk factors and performance of the tests being used.
FeLV overview
FeLV is a gammaretrovirus that infects domestic cats and other felidae worldwide. FeLV is transmitted vertically and horizontally. Infection spreads rapidly within households through oronasal contact with virus- containing secretions, principally saliva. Vaccination and changes in management practices have reduced the global prevalence of FeLV infection. However, testing for FeLV is still relevant because FeLV carries a poor prognosis, there is no effective treatment and transmission of infection to in contacts should be prevented.
FeLV testing and outcomes
Screening point-of-care (PoC) tests detect viral antigen, p27, in whole blood, plasma or serum. These kits usual perfom very well; the IDEXX SNAP Combo showed 100% specificity and sensitivity for detecting FeLV antigenaemia recently.(1) Following FeLV exposure,
cats initially test antigen positive. A stable outcome, influenced by age, immune status and virus dose, is reached within weeks. Around 30% of exposed cats develop progressive infection (persistent antigenaemia, high proviral load). Cats with progressive FeLV infection are the source of infection for naïve cats, and they
have reduced life-expectancy that is often only days
or weeks. FeLV-related diseases include anaemias, immunosuppression and lympho or myeloproliferative diseases. In the remaining exposed cats, antigenaemia
is transient, but residual virus can be detected by quantitative polymerase chain reaction (qPCR, also called
There are three (or four) diseases of the biliary tract in humans which all have a very similar appearance on histology and yet are clinically very distinct.
· Primary sclerosing cholangitis
· Primary biliary cirrhosis
· IgG4+ cholangitis
· Sphincter of Oddi dysfunction)
I will describe these as an example of how relying entirely on histology in cats may be leading us to
put several diseases together. We need to develop better methods of imaging and blood tests to help us understand these feline diseases further.
Your Singapore, the Tropical Garden City
  In a recent, multi-centre, unfinished (!) project, we looked at 39 cases of chronic cholangitis to ask the questions: what type of pathology is present? Are any similar to primary sclerosing cholangitis in humans?
Based on the human classification systems, a human pathologist, grading the cats ‘blind’, categorised nine cases as secondary biliary cirrhosis – suspected chronic extra-hepatic obstruction; seven cases as PSC-like changes; five cases as vanishing bile duct syndrome; one case as PBC-like changes and the rest non-specific ‘cholangiopathy’. Whatever is going on in these cats with chronic cholangitis, we undoubtedly have several diseases present and we are undoubtedly missing the diagnosis of extra-hepatic biliary tract disease in many cases.

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