Title: Feline Immunodeficiency Virus
1Feline Immunodeficiency Virus
- By Neva DeCoux, Michelle Kwok
2Etiology
Feline immunodeficiency virus (FIV) is a type of
lentivirus ("slow virus") classified by a long
incubation period (may last as long as 6 years)
that slowly develops into the disease. It is in
the same retrovirus family as feline leukemia
virus (FeLV) and human immunodeficiency virus
(HIV). It attacks the immune system, and as a
result, the cat is unable to fight off various
infections and cancers. Approximately 2.5 of
cats in the United States are infected with FIV.
3Cause
- The virus, a lentivirus, interacts with
lymphocytes, changing their ability to function
normally in the immune response process. - The resulting lymphopenia, loss of memory cell
function, and decrease in antibody production
from T-cell stimulated lymphocytes leaves the cat
open for opportunistic infection.
4Retroviruses
- Retroviruses are species-specific. This means a
feline retrovirus like FIV will only infect cats
a human retrovirus such as HIV will only infect
humans. - Retroviruses are made up of RNA. In the host, the
RNA is transcribed into DNA and incorporated into
the DNA of the hosts cells. - Retroviruses are fragile, being easily
inactivated by ultraviolet light, heat,
detergents, and drying.
5History of disease
- It was first discovered during the investigation
of a disease outbreak in a previously healthy
colony of rescue cats at UC Davis in 1986 by
immunologists Janet Yamamoto and Niels Pederson - The colony had been showing similar signs to
people with acquired immunodeficiency syndrome
(AIDS) caused by human immunodeficiency virus
(HIV) infection. - Yamamoto started working on a vaccine for FIV at
UC Davis.
6Signalment
- Vulnerable at any age
- Outdoor, free-roaming felines
- are at greater risk
- Male felines are 1.5 to 3 times more likely to
become infected then a female feline. - Is rare in catteries
- More predominant in free-roaming aggressive male
cats due to transmission by bite wounds - Infects domestic cats, and can also infect wild
felines including snow leopards, lions, tigers,
jaguars, Florida panthers, and bobcats.
7Roaming Male Feline
8Feline with FIV
- - Feline Male was diagnosed to be FIV positive.
9Transmission
The primary modes of FIV transmission are deep
bite wounds and scratches, where the infected
cat's saliva enters the other cat's bloodstream.
- Casual, non-aggressive contact does not appear to
be an efficient route of spreading FIV. - On rare occasions infection is transmitted from
an infected mother cat to her kittens, usually
during passage through the birth canal or when
the newborn kittens ingest infected milk - FIV transmission in utero or through the mother's
milk is very rare. It could possibly occur if the
queen is infected during pregnancy or while
nursing the kittens. - Queens infected with FIV prior to the pregnancy
usually have non-infected kittens.
10Transmission
- Sexual contact is not a major means of spreading
FIV. - Although FIV is a lentivirus similar to HIV (the
human immunodeficiency virus) and causes a
disease in cats similar to AIDS (acquired immune
deficiency syndrome) in humans, it is a highly
species-specific virus that infects only felines.
11Clinical signs
- Poor coat condition and persistent fever with a
loss of appetite are commonly seen. - Lethargy
- Inflammation of the gums (gingivitis) and mouth
(stomatitis) and chronic or recurrent infections
of the skin, urinary bladder, and upper
respiratory tract are often present. - Persistent diarrhea
- Slow but progressive weight loss is common,
followed by severe wasting late in the disease
process. - Various kinds of cancer and blood diseases are
much more common in cats infected with FIV, too. - In unspayed female cats, abortion of kittens or
other reproductive failures have been noted. - Some infected cats experience seizures, behavior
changes, and other neurological disorders.
12Clinical Signs
- Febrile episodes
- Lymphadenopathy (chronically swollen lymph nodes)
- Persistent infections unresponsive to treatment
- Weight loss
- Gingivitis
- Ocular lesions
- Slow-healing traumatic wounds
- Behavior abnormalities
- Chronic upper respiratory infections
- Anemia
Pansystemic disease
13Diagnostic tests and Expected results
- Immunoblotting
- Uses anti-bodies to detect HIV related proteins
- PCR (polymerase chain reaction)
- Detects the virus itself
- Very useful for detecting infection in kittens
born from the FIV positive mother - Check for false positives
- Elisa (Enzyme-linked immunosorbent assay)
- Detects anti-FIV antibodies
- Most common
- Rapid and reliable method
- Does not work well with very early infection
- False positive is very rare
- Repeat test to be sure
14Diagnostic Tests
- ELISA test (enzyme-linked immunosorbent assay)
will be positive - -It is possible to get false positive or false
negatives from these results for the following
reasons
False Positive False Negative
Kittens born to FIV infected mothers may have received antibodies from their mothers milk. This doesnt mean that the kitten has FIV, just that it has received antibodies to FIV. Kittens that test positive should be re-tested at a later date. It usually takes several weeks for the antibodies for FIV to appear in the blood, if a cat is tested prior to this it will show a negative test result.
If a cat has received the FIV vaccine the test results will show up positive. If the cat is in the later sages of infection it may not be producing antibodies.
15 Elisa Test ? PCR Test
16Diagnostic Test cont.
- A FIV PCR (polymerase chain reaction) test is
available in some commercial laboratories. PCR
detects the presence of the FIV virus in the
blood. - Western blot test or IFA (Immuno-Fluorescent
Antibody Test) If a cat has tested positive to
FIV it is sometimes recommended to follow up with
either a Western Blot Test or an IFA test. - If your cat has tested positive to FIV but you
are not sure if it has had the vaccine, or want
to be sure it does/doesn't have the virus then
you may be able to request a PCR (polymerase
chain reaction) test, which will be able to
detect the presence of FIV DNA in the blood. - Urinalysis elevated protein levels
- CBC (stage 3) anemia, lymphopenia, neutropenia
17Western Blot Test
18Recommended Treatment
- No treatment to eliminate the virus
- Depends on the proper health management
- There are some anti-viral medications but they
are not 100 effective in improving the immune
system
19Treatments
- FIV is treated symptomatically.
- Medications
- -Antibiotics for secondary infections
- -Appetite stimulants
- -Corticosteroids
- -Immune modulators
- Dental extractions with chronic gingivitis and
stomatitis - Some also require nutritional support, fluid
therapy, and dental care.
20Prognosis
- It is not possible to determine how long a FIV
positive feline will live, but with proper care
and supportive therapy they can live a full life.
21Prognosis
- The outlook for cats that show severe, chronic,
multiple signs of disease is poor. - If clinical signs have developed only recently
and are not severe, there is a reasonable
prospect of improvement with treatment, which may
be maintained for some time. - Greater than 50 of infected felines remain
asymptomatic within 2 years after diagnosis - Treatment usually consists of supportive therapy,
often antibiotics, possibly coupled with
antiviral therapy. - Felines in the terminal stage of the disease
survive less then one year. - For kittens can detect maternal AB hence re-test
after 6 months. - Average life span from diagnosis to death is
roughly around 5 years.
22Pathologic lesions
- University of Bristol School of Veterinary
Science Study - A range of tissues from a total of 17 cats
naturally infected with the feline
immunodeficiency virus was examined
histologically. - In 11 cases, chronic inflammatory lesions were
present in various tissues including, most
commonly, the intestine, brain and lung.
Extensive inflammation in the intestinal wall was
present in seven of the cats. - No particular bacterial organisms were
demonstrated in these inflammatory lesions. A
range of changes was present in the lymph nodes,
including hyperplasia, atrophy or a mixed
pattern. Erythrophagocytosis was a consistent
feature. - Some present with dysplastic nodes characterized
by follicular atrophy (wasting away of the
follicles), paracortical cell depletion, and
fibrosis (excess fibrous connective tissue).
23Pathologic lesions of disease
- The most commonly occurring lesions (seen in 91
of infected cats) were thymic atrophy,
generalized lymphoid hyperplasia, and bone marrow
hyperplasia. - The second most common lesions were splenic
lymphoid hyperplasia and thymic follicle
formation (7883 of cats). - A third set of miscellaneous lymphoid and mucosal
lesions was confined to 30 of cats.
24Prevention
- Isolate affected cats.
- Keep unaffected cats away from feral cats.
- A vaccine for FIV currently is available
- - may test positive for FIV at a later date
- Spaying and neutering outdoor cats can limit
exposure by decreasing aggressive behaviors. - - especially males
25FIV Vaccine
- Cons
- Does not provide full protection against all
strains. - Since it is a killed virus, adjuvants are used
which carry the possibility of vaccine associated
sarcomas forming. - Vaccinated feline will always be FIV positive.
Can be a problem if lost and placed in a shelter.
- Pros
- Provides 82 protection against strain A.
No blood test can differentiate between a
vaccinated cat and a truly infected FIV positive
cat.
26Client Education
- Educate about the virus and vaccine
- FIV is a progressive disease
- FIV infected felines should be confined indoors
to prevent the spread of the virus - FIV infected felines should be spayed or neutered
- Should be fed complete and balanced nutritional
diet - Uncooked food should not be fed (Ex raw meat,
eggs and unpasteurized dairy products) - Wellness visits for FIV infected felines should
be scheduled with your veterinarian at least
every six months - Close monitoring of health and behavior
- Test all new additions to the cats household.
27References
- http//www.vet.cornell.edu/fhc/brochures/fiv.html
- http//www.knowyourcat.info/health/fiv.html
- http//www.fivprognosis.org/owners.html
- http//www.peteducation.com/article.cfm?c11316a
id213
28References
- Common Diseases of Companion Animals
- Veterinary Technicians Daily Reference Guide
- www.vet.cornell.edu
- www.merckvetmanual.com
- www.cat-world.com.au
- http//gateway.nlm.nih.gov
- http//fabcates.org
- http//sciencedirect.com