Chapter 13. Biology and Diseases of Cats Flashcards
1
Q
General research uses for cats
A
Neurology - locomotion, spinal trauma; retrovirus & zoonotic diseases; inherited diseases
2
Q
Viruses studied in cats
A
- Feline foamy virus (FFV) - viral vector
- FIV - model for HIV/AIDS
- FeLV - model for HIV/AIDS and retroviral disease
- Feline calicivirus - development of vaccines; model for human norovirus
- Feline coronavirus - model for SARS
- Feline parvovirus - model for parvoviruses; vaccine development
3
Q
Bacteria studied in cats
A
- Helicobacter pylori, H. felis - pathogenesis & zoonotic aspects
- Yersinia pestis - pathogenesis & zoonotic aspects
- Bartonella henselae - pathogenesis & zoonotic aspects
4
Q
Protozoa studied in cats
A
Toxoplasma gondii - vaccine development, zoonotic aspects
5
Q
Domestic cats are susceptible to which 3 retroviruses?
A
- FIV - genus Lentivirus
- FeLV - genus Gammaretrovirus
- Feline foamy virus (FFV) - genus Spumavirus
- FFV generally asymptomatic; FeLV fulminant disease or controlled but not eliminated
6
Q
FeLV cat models
A
- FeLV studied for retroviral-induced immunodeficiency
- Effective vaccines available
- After infection a fraction of cats are persistently viremic, with viral excretion through saliva & nasal secretions
- Dx: major viral core protein (p27 gag) via ELISA
7
Q
FIV cat models
A
- One of the most relevant naturally occurring models of HIV
- Resembles HIV in tissue and cell tropism but is antigenically distinct
- Cell-associated viremia occurs within 1-2 wks and remains persistent
- Immune system changes: lymphadenopathy, neutropenia, decreased lymphocyte proliferative response, increased susceptibility to opportunistic infx; sometimes B cell lymphoma, myeloproliferative disease
8
Q
Helicobacter felis cat models
A
- Model for H. pylori, which causes gastritis, peptic ulcers, gastric carcinoma in humans
- H. felis has a wide host range
- Cats can be naturally infected with H. felis and H. pylori
9
Q
Spinal cord injury cat models
A
- Despite their small body size, the spinal cord of cats is similar in length (34 cm) and anatomy to human spinal cord (40-45 cm)
- Cat models demonstrated that spinal cord has intrinsic circuitry to generate locomoton
- Used recently to study embryonic stem cell transplantation, neurotransmitters & molecular genetics of the circuitry controlling locomotion in the spinal cord
- Successful grafting of peripheral nerves onto the spinal cord has been demonstrated in cats
10
Q
Sleep research cat models
A
- Adult cats spend up to 2/3 of their time sleeping
- Cats have been used to model obstructive sleep apnea (OSA) - occurs when cats sleep in supine position with neck flexed & can be trained to wear CPAP
11
Q
Parkinson’s disease cat models
A
- PD can be induced in cats & many other species using 1-methyl-4-phenul-1,2,3,6-tetrahydropyridine (MPTP); however, unlike humans, cat recover
- Cats experience sleep interruptions during the acute phase = possible model of sleep disorders in Parkinson’s disease
12
Q
CNS cat models
A
- The CNS and brain of the cat is well characterized and has similar anatomy to humans
- Cats are a good model for gene therapy trials for neurological disorders such as lysosomal storage disease
13
Q
Centers for feline inherited diseases
A
- Center for Comparative Medical Genetics (CCMG) - characterizes & makes available cat modes of human diseases; maintains colonies of animals for studies of α-mannosidosis, mucolipidosis II, Neimanpick-C, glycogen storage IV, pyruvate kinase deficiency, porphyria, hypothyroidism
- Cat Phenotype and Health Information Registry (CAT PHIR) - defines feline genetic models & characterizes the specific mutations, incl PRA and PCK in Persian cats, and hypotrichinosis in Cornish Rex
14
Q
Problems with introducing random source cats to a research facility
A
- Inapparent or latent diseases (e.g., FIV, FIP) may be introduced
- Variable tractability
- If brought in, a prolonged 8-12 week quarantine is needed with identification of diseases, parasite elimination, vaccination
- The National Research Council states that IACUCs must give rigorous consideration to the scientific justification for the use of random-source rather than purpose-bred cats
15
Q
Best means of obtaining substantial numbers of cats for research?
A
Establish institutional breeding colony
16
Q
Housing requirements for cats
A
- Primary enclosure height: at least 24 inches
- Floor space: 3 ft^2 per cat weighing less than 8.8 lg (4 kg) & 4 ft^2 for cats weighing more
- Queens with nursing kittens require additional space
17
Q
Cats should be socially housed unless…?
A
- Single housing for particular experimental objectives
- Temporary single housing for collection of specimens, administration of treatments, or observation
- Cats that are aggressive towards other cats
18
Q
Harem breeding of cats
A
~4-6 queens per tom
19
Q
Maximum number of cats in a single room
A
-Typically 20-25 animals is the maximum for a successful breeding room, as long as there is enough floor, perch, feeding, and litter space
20
Q
Housing of queens and kittens
A
- Housing compatible pregnant queens together before delivery may lead to sharing nursing and neonatal care
- Queens nursing litters & kittens under 4 months of age should not be housed with other adult cats
21
Q
Perch space for cats
A
- USDA regulations require that enough perch space is available for all cats to rest comfortably on a perch surface simultaneously
- If the resting areas are placed so low to the ground that a cat cannot rest comfortably underneath it, the resting surface will be considered floor space
22
Q
Litter for cats used in research
A
- Can be any clean, dust-free, absorbent material (e.g., extruded corn pellets)
- One box per two cats is recommended
- Soiled litter must be removed and replaced daily to minimize cat-to-cat transmission of enteric pathogens
23
Q
How long does it take Toxoplasma gondii oocysts to sporulate?
A
1-5 days
24
Q
Temperature and humidity range for cats in the Guide
A
- 64-84 F
- 30-70%
25
Stress in cats used in research
- As natural predators, cats have keen senses & heightened fight-or-flight responses = susceptible to environmental stress
- Become readily entrained to daily activity patterns
- Unpredictable caretaking & handling are potent stressors
- Overcrowding & insufficient resting and hiding places also increase stress
- Ability to hide profoundly decreases cortisol concentrations in cats
26
Signs of stress in cats
-Decreased activity (grooming, social interaction), withdrawal behavior, altered appetite
27
Communication between cats
- Visual: body posture & facial expression
- Auditory: meowing, chirping vs. hissing, shrieking
- Tactile: body & nose rubbin
- Olfactory: urine spraying, rubbing scent glands
- Affiliative behaviors include mutual grooming & allorubbing; these behaviors more common in females; Play behavior & food sharing common in kittens & adolescents
28
Maternal behavior in cats
- Primary social pattern of the female cat; queens have strong maternal instincts
- Adult queens form social groups along with their kittens & juvenile offspring;
- Cooperative nursing is common
- Kittens raised in communal nests develop faster and leave the nest sooner
29
Socialization period for kittens
3-8 weeks
30
Tom cat behavior
- Adult toms reside within one group or roam between groups
- Commonly exhibit aggressive behaviors toward other toms with urine spraying, fighting
- In contrast, usually affiliative towards females = housed with spayed females when not breeding
- Neutered males display less agonistic behaviors towards other cats
31
Housing cats to exclude pathogens
- Facility should have various areas to house different life stages, health statuses, as well as quarantine
- Quarantine cats that have had exposure to infectious diseases (i.e., non-SPF cats) ideally for at least 6 weeks = time it takes cats to seroconvert against FIV or become antigen-positive to FeLV
- Quarantine cats from SPF sources for at least 1 week
- Handle queens with young litters first; handle youngest & most immunocompromised before others
- Equipment should be room-specific
- Provide enough litter boxes to decrease waster material accumulation & disease spread
- Air exchanges of 10-12 per hour & using filtration in air-supply system help reduce air contaminants
32
Recommended regular caretaking operations for cat facilities
-Daily operations should include vacuuming and
mopping floors, disposal of soiled litter, replacing soiled cardboard nesting boxes, and washing utensils for water
and food as needed
-Weekly procedures should include washing litter boxes and food/water utensils in 180°F
water, scrubbing soiled areas, and replacing nesting boxes; cage washer washing of caging units
33
What disinfectants are effective against nonenveloped viruses like feline panleukopenia virus & feline calicivirus?
-Aldehydes, hypochlorite, peracetic acid
34
What disinfectants are effective against dermatophytes?
-Require much higher concentrations & repeated applications of hypochlorite compared to nonenveloped viruses
35
What disinfection is needed for coccidia?
-Steam cleaning & disinfectants specifically labeled for coccidia
36
Environmental enrichment for cats
- Toys and play that appeal to cat's predatory instincts
- Items that can be scent marked
- Provide multiple enrichment items for group-housed cats so they are not all hoarded by dominant cats
- Hiding places
- Extra human interaction for singly housed cats
- Perches for resting ('rest boards')
37
Reproductive biology of queens
- First estrous cycle at 5-9 months of age (range 3.5 to 18 months); usually occurs after reaching body weight of 2 kg or more
- Group housing, especially introduction of a tom or estral queen, provides social stimuli that hastens onset of estrus
- Seasonally polyestrus: in Northern hemisphere season begins in Jan-Feb & lasts until fall; anestrus persists from Oct-Dec
- 10 or more hours of light per day required for reproductive cycling
- Peak sexual activity occurs btwn 1.5-7 years, with average of 2-3 litters per year & 3-4 kittens per litter
- If allowed, queens may accept a number of males & therefore litters may have multiple sires
- Queens less than 1 year old & 8 years or older tend to cycle irregularly, have smaller litters w/ more abortions, stillbirths, birth defects
- Following a normal lactation, queens return to estrus in 2-8 weeks (avg 4); can return to fertile cycling while nursing
- Queens need a period of rest to regain body condition after nursing
38
Photoperiod for maximum fertility period and estrous cycling in cats
- 14 hr light photoperiod with natural daylight spectrum fluorescent bulbs
- Estrous cycling typically occurs within 7-10 wks of instituting this light cycle; this period can be shortened if preceded by a nonstimulatory light cycle or 8 or fewer hours or if tom cat or estral queen introduced at same time as increased light duration
39
Rest periods for queens
- Provide a period of short days (8 hr of light or less) for 4-6 weeks each year to ensure anestrus & reproductive rest
- This may ultimately enhance reproductive performance
40
Reproductive biology of toms
- Tomcats reach puberty at 8-13 mths of age
- Sexually active year-round, polygamous
- Peak reproductive function between 2-8 years of age
- Behavior traits - docile, tractable, east to handle - have been found to relate to traits in kittens
41
Neonatal isoerythrolysis
- Blood type A toms should not be bred to type B queens to prevent neonatal isoerythrolysis
- Blood type B is rare in domestic shorthairs, but common in certain purebreds
42
Infertility in cat colonies
- Inbreeding is a common cause of reduced fecundity, birth defects, infertility
- Periodically review breeding records to identify fertility, fecundity, lactation problems and abnormal viability of kittens in utero and postnatally
43
Assisted reproduction in cats
- Colonies of domestic cats are used as models to develop techniques of assisted reproduction for management of valuable domestic cats & endangered nondomestic cats
- Techniques include cryopreservation of spermatozoa, laparoscopic oviductal embryo transfer
- Cats are the first carnivore for which a transgenic model is available - manipulation of feline gametes & embryo transfer to create transgenic line expressing antiviral restriction factor
44
Nutrition for cats
- Obligate carnivores; adapted for high protein diets
- Diet of free-ranging cats contains ~52% crude protein
- Cats require dietary supplementation of taurine, arginine, arachidonic acid, Vitamins A, D, and many B (niacin, thiamine, etc.) - in the wild these are present in tissues of prey
- Intestinal tract of cats is only 4.2 times their body length (compared to 6 times longer in dogs) = evolved to accommodate consumption of highly digestible prey
- Vitamin A deficiency d/t gamma-irradiation of diet reported to cause progressive hind limb ataxia & proprioceptive defects = leukoencephalomyelopathy
- Taurine deficiency in diets leads to retinal degeneration; diets marginally deficient in taurine can produce dilated cardiomyopathy
45
Commercial diets for cats
- To avoid nutritionally incomplete diets, select a commercially prepared diet labeled with a 'nutritional adequacy statement' = diet has passed Association of American Feed Control Officials (AAFCO) Cat Food Feeding Protocol
- AAFCO feeding trial assess digestibility, bioavailability, and palatability
- Commercial cat diets can provide a source of contamination for SPF colonies (e.g., Salmonella)
- To avoid contamination & dietary imbalance due to autoclaving or irradiating diet, use a diet specifically formulated for laboratory cats
- Free-choice feeding mimics pattern of free-ranging cats that consume multiple small meals over the course of 24 hr, but can lead to excess weight/obesity
- Canned foods may spoil if left out for more than 8-12 hr
46
Energy requirements of cats
- Adult cat at maintenance: 100 kcal/(kg body weight)^0.67 per day
- Assessing muscle condition is important because cats tend to catabolize lean body tissue under conditions of acute stress & loss of muscle tissue may not be readily appreciated with traditional body scoring
47
Health risks of obesity in cats
- Increased risk of diabetes mellitus, hepatic lipidosis, urinary tract disease
- White adipose tissue releases several factors including steroid hormones, growth factors & various cytokines such as leptin, adiponectin, resistin, visfatin (adipokines)
- Leptin is several fold higher in obese cats compared to lean cats without leading to appropriate physiological response of appetite suppression
- Obesity can upregulate mRNA expression of proinflammatory cytokines TNFalpha & interferon-gamma in adiposites
48
Energy requirements of queens
- Queens gain weight in a linear fashion throughout gestation
- Energy requirements increase by 25-30% by midgestation
- Energy requirements continue to rise to 3-4x maintenance after parturition to provide for lactation
- Peak lactation occurs 2-3 weeks postpartum
- After weaning, mild production and mammary congestion can be decreased by fasting queens for 24 hr before returning to maintenance feeding
49
Preventive medicine for cats used in research
- Selection for disease resistance, docile temperament, breeding and maternal care success in queens in breeding programs should be considered
- Cats used in infectious disease or vaccine research may not be vaccinated or may be vaccinated only with killed vaccines to avoid perturbations to the immune response
- Early cessation of immunization protocols is the most common form of immunization failure
- Young kittens (less than 6 mth old) represent a main target population for immunization due to their increased susceptibility to infection
50
Maternal antibodies in cats
-Maternal antibodies acquired through colostrum can interfere with immunization as late as 16 wk of age in kittens & will vary depending on pathogen
51
Considerations for cat vaccination protocol
-The closed/open status
of a colony, animal density, research use of animals, and potential exposure (either through fomites carried into the facility or geographical presence of pathogens)
-Type of vaccine administered can vary depending on the reproductive status of the individual animal; vaccinating pregnant queens generally not recommended (possibility of infecting fetus during pregnancy or lactation)
-Ex: modified live feline panleukopenia virus vaccine given to a pregnant queen could cause cerebellar hypoplasia in the kittens (inactivated vaccines should be used instead if must be given)
-Multivalent panleukopenia vaccines found to induce more lethargy post-vaccination
52
Overcrowding in cat colonies
- One of the most potent stressors in cats
- Increases number of pathogens, susceptible, animals, & number of asymptomatic carriers in a given groups
- Increases likelihood of disease transmission d/t direct contact and fomites
- Keep groups as small and stable as possible
- Kittens should remain only with queens and littermates until weaning
53
Synthetic feline facial pheomones (FFP)
- Recommended in treatment of stress-related behaviors due to apparent anxiolytic effect on cats
- Can decrease urine-spraying according to one study; but other studies have found inconsistent results for reducing stress in unfamiliar environments
54
Upper respiratory tract infections in cats - etiology
- Feline herpesvirus-1 (FHV-1) & feline calicivirus (FCV) are primary agents; also Chlamydia, Mycoplasma, reovirus, Bordetella
- Chlamydophila felis - normally assoc w/ serous conjunctivitis, mild URI that self-resolve; multivalent vaccine available
- Mycoplasma felis - primary conjunctivitis, anemia, URI; can treat with antimycoplasmal drugs
- Bordetella bronchiseptica - acute bronchitis, pneumonia, ocular discharge, death; vaccination may be warranted in colonies with a history of infection
55
Feline herpesvirus 1 (FHV-1)
- FHV-1 - subfamily Alphaherpesvirinae; feline viral rhinotracheitis; acute rhinitis, conjunctivitis, corneal ulcers, sneezing, conjunctival hyperemia, coughing; shed in oculonasal discharge; transmission is direct contact; acute disease is 10-14 days; can shed for up to 3 weeks
- Spreads to trigeminal nerve to establish latency
- Over 80% of cats that recover become carriers & intermittently shed following stress (glucocorticoid administration, parturition, relocalization of cats)
- Shedding begins within 1 week of stressful event & continues for ~2 weeks
56
Feline calcivirus (FCV)
- Acute URI, acute stomatitis, lingual ulceration
- Chronic stomatitis (possibly immune-mediated) & limping syndrome d/t idiopathic acute synovitis have been reported
- Infected through oronasal route - transient viremia in following 3-4 days; healing takes place 3-4 weeks following infection
- Virulent systemic disease recently assoc w/ FCV in US and Europe: systemic inflammatory disease, DIC, organ failure, death; mortality rate up to 67%
- Infected cats shed FCV for 30 days; many cats clear infection but others can continually shed virus (potentially lifelong; rare)
- FCV may undergo mutations to its capsid protein, possibly avoiding host immune response
57
Upper respiratory infection in cats - treatment
- Primarily supportive - clean eyes & nose; mucolytic agents; nebulization with saline; fluids; nutrition maintenance
- Antibiotics is secondary bacterial infection
- Acyclovir and famciclovir can be beneficial for FHV-1
58
Upper respiratory infection in cats - vaccination, control
- Parenteral & intranasal vaccines available for FHV-1 & FCV
- Multivalent vaccines coupled with FPV are common
- Vaccination against FCV will NOT prevent shedding or clinical disease & does not protect against all FCV strains
- FHV-1 very labile in environment, tends to persist for only 24 hr
- FCV can persist in environment for up to 2 wks & transmit via fomites; eliminate with bleach
59
Feline parvovirus (feline panleukopenia)
- Highly contagious, causes serious clinical disease
- Easily controlled by vaccination
- Transmission: indirect via fecal-oral
- Clin signs: diarrhea, lympopenia, neutropenia, thrombocytopenia, anemia, cerebellar hypoplasia in kittens, abortion
- Kittens are most vulnerable with mortality as high as 90%
- Nonenveloped = very resistant in environment & rapidly accumulates in environment d/t high shedding
- Passive immunity from maternal antibodies tends to last 6-8 weeks; immunity gap can occur where antibody levels too low to protect kitten but high enough to interfere with vaccination = vaccinate kittens as early as 6 weeks & repeat every 3-4 weeks until 16-20 wks
- Repeat vaccination at 1 year, then every 3 years
60
Feline infectious peritonitis (FIP) - etiology
- May arise in otherwise healthy cats, cannot be distinguished serologically from other coronaviruses, causes recurring appearance of disease that tends to be fatal
- 2 types of coronaviruses in cats: feline enteric coronavirus (FECV) & FIP virus (FIPV) - antigenically & morphologically indistinguishable from each other
- Both genus Alphacoronavirus
- FECV ubiquitous & avirulent
61
Feline infectious peritonitis (FIP) - epizootiology
- FECV endemic in nearly all environments with large numbers of cats; spread fecal-oral & assoc w/ subclinical or self-limiting GI signs (diarrhea)
- Viral shedding of FECV from small and large intestine typically for 1 week after infection but up to 18 months
- Immunity is not lifelong - recovered cats can be reinfected with typically the same strain
- Immunity btwn FECV & FIPV NOT crossprotective
- A mutation in FECV is believed to cause FIP - mutation at a spike protein cleavage site theorized to lead to altered fusion properties that provide for macrophage tropism, systemic spread, development of FIP
- FECV mutations differ between littermates & even within different tissues of same animal; kittens most susceptible to this mutation during primary infection
- Coinfections with other viruses & stress increase incidence of FIP
- Other risk factors for FIP: genetic susceptibility, coronavirus titer, proportion of FECV shedding, prevalence of chronic shedders in colony
62
Feline infectious peritonitis - clinical signs
- Clinical disease more common in young animals from 5-6 weeks up to 16 months of age
- 2 Forms of FIP = effusive 'wet' form & dry form
- Effusive Form: more common, shorter incubation period (2-14 day); may be subclinical for weeks with affected young appearing unthrifty; signs: fever, anorexia, malaise, weight loss, painless abdominal distension (ascites; mucinous yellow fluid); dyspnea from pleural & thoracic effusion; ocular & neurologic signs; scrotal edema; synovitis due to immune complex formation
- Dry Form: less common; granulomatous lesions in various organs (kidneys, mesenteric LNs, liver - lesion painful on palpation); CNS involvement; ocular disease
63
Feline infectious peritonitis - diagnosis
- Serology does not differentiate FECV from FIPV
- Effusion aspiration - high protein content (>35 g/l); exudative effusion with neutrophils & macrophages
- Specific mutation at S1/S2 site may allow diagnosis of FIP prior to development of disease
64
Feline infectious peritonitis - prevention & control
- Typically fatal; no current effective treatment
- A reliable vaccine has not been developed
- Virus may persist for up to 2 months in environment
- Prevention: minimize fecal-oral spread
65
Fleas in cats
- Cause marked allergic dermatitis in many adults
- Vectors for tapeworms (Dipylidium caninum), many infectious diseases
- Cats & kittens are extremely sensitive to toxic effects of insecticides = use products intended for cats
- Eradication includes environmental sanitation to eliminate opportunities for larval development
66
Ear mites in cats
- Otodectes cynotis - most common cause of otitis externa in cats
- Live in external ear canal, feed on tissue fluids & produce irritation
- Clin signs: thick, dark-brown exudate consisting of cerumen & exfoliated debris; head shaking; scratching at ears; pinnae excoriations
- Dx: otoscopic examination or microscopic examination of exudate in mineral oil
- Tx: if diagnosed in a colony, all cats whether infected o not should be treated; ivermectin (200-300 ug/kg SC Q2 weeks x 2 treatments) is a safe, inexpensive option
67
Endoparasites in cats
- Roundworms: Toxocara cati, Toxascaris leonina
- Hookworms: Ancylostoma & Uncinaria
- Transmission: transmammary most common route for roundworms & hookworms; also from ingesting contaminated soil
- Larvae ingested by adult cat migrate to body tissues & persist for years, then reactivated & travel to mammary glands to be shed in milk
- Infested kittens may have diarrhea as early as 2-3 weeks of age
- Hookworms can cause blood loss & anemia; female worms produce eggs that pass in feces & can persist in soil for years
- Control: proper sanitation, routine deworming of kittens; pyrantel pamoate (8-10 mg/kg PO Q3 weeks x 3 treatments) effective for roundworms & hookworms
- Adult cats acquire immunity & rarely reinfested
- In humans: hookworms = cutaneous larval migrans; roundworms = visceral larval migrans
68
Coccidia in cats
- Cats are definitive host for Isospora felis & Isospora rivolta
- Young kittens usually affected
- Eggs passed in feces & sporulate in as little as 12 hr; adult forms replicate in small intestine & cause vilous atrophy, dilated lacteals, lymphoid proliferation of Peyer's patches
- Clin signs: watery diarrhea that may contain blood, vomiting, abdominal discomfort, anorexia
- Dx: eggs on fecal float
- Tx: sulfadimethoxine
- Control: eggs resistant to many disinfectants - prompt removal of feces & steam cleaning surfaces helps decrease coccidial egg load in environment
69
Giardia in cats
- Less common than coccidia
- Occur in condition of poor sanitation, particularly in kittens
- Parasitization of small intestine may result in diarrhea
- Tx: metronidazole or fenbendazole
70
Personnel health concerns when working with cats
- Cat Scratch Disease: Bartonella henselae; transmitted by bite or scratch wounds or by fleas; personnel should wash wounds thoroughly & seek medical attention if not responding to usual treatment
- Dermatophytosis: Microsporum canis; dx by culture
- Toxoplasmosis: obligate intracellular protozoa; transmission by ingestion of infected feces/soil or undercooked meat; diagnosis is difficult; use gloves when handling litter & wash hands
- Rabies: consideration vaccination of cats because of legal obligations when shipping, otherwise little risk with closed colony derived from disease-free stock
- Cat salivary & urine proteins are potent allergens; 5 cat allergens have been characterized; cats more commonly implicated in ashthma and allergic disease than other pet species
