INFECTIOUS DISEASE

The Latest Recommendations for Ringworm by Lorraine Shelton

The World Association for Veterinary Dermatology has recently released their guidelines for the treatment of feline ringworm, most commonly caused by the infection of the outermost layer of skin with the fungal organism arthroderma otae (previously known as microsporum canis). 

Although ringworm is often a self-limiting disease, where the immune system of the cat can clear signs of infection over the period of a few months even without treatment, the fact that it can be so easily spread to other cats, and even humans, makes it a disease that we need to take seriously as cat fanciers. Appropriate treatment can shorten the course of the disease and prevent transmission.

In the general cat population, ringworm is less prevalent than allergic dermatitis, bacterial infections, ear mites, and fleas, so these potential causes of skin issues need to be considered as well. The severity and presentation of ringworm infection are a reflection of the individual cat's immune and inflammatory responses. Cats living in high-stress situations, including high-density environments, are at greater risk of developing dermatophytosis than those from less stressful living situations. Fewer cats in more space tend to be healthier.

A cat must have a strong enough immune system to be able to produce a strong cell-mediated immune response to infection, in order to completely respond to treatment.

The primary mode of dermatophyte transmission is through direct contact with infected hairs or lesions. Keep in mind, however, that infective spores are shed by cats long before clinical signs are apparent. Despite commonly held fears of cat owners, infection from a contaminated environment is rare. Trauma to the skin can predispose a cat to infection, therefore fleas and mites must be controlled as part of the treatment plan.

Diagnosis:
Wood's lamp examination,
Culture,
PCR (polymerase chain reaction) testing.

Wood's lamp examination under magnification of superficial skin scrapings and hairs plucked from lesions was found to be positive in 87.5% of cases of M.canis dermatophytosis. A "black light" is not the same as a Wood's lamp: while both emit portions of the ultraviolet light spectrum, a black light emits a substantial amount of visible light, which makes it hard to see the fluorescence. 

A negative dermatophyte PCR in a treated cat can be used to establish that the cat is cured and no longer infectious. Fungal cultures are associated with a significant level of false negative and false positive results, however a negative fungal culture in the absence of lesions, combined with a negative Wood's lamp evaluation can be used to demonstrate that treatment has been successful. 

Glowing hair tips on Wood's lamp examination of a treated cat does not necessarily mean the cat is not cured. Because the fluorescence is associated with a pigment (pteridine) produced by the organism, hairs that fluorescence only at the tips is a common finding in cured cats.

Because skin lesions and infected hairs transmit the infection, isolation of infected cats, topical treatment of the skin and coat, and removing shed hair completely from the premises are the initial, essential steps in treatment. Whole body, twice a week lime sulfur or enilconazole dips have been demonstrated to be effective topical treatments. Accelerated hydrogen peroxide, climbazole, and terbinafine topical treatments have also been used, but efficacy of these agents has not been demonstrated through studies. 

Treatment:
Treating only lesions is not recommended, as infectious spores can be found distant from these lesions. Unfortunately, topical treatment often fails without concurrent systemic treatment with itraconazole, fluconazole, or terbinafine. One study demonstrated that with combined topical and systemic treatment, cats can be non-infectious to humans and other cats within a week. However, a longer treatment course is needed to prevent re-infection.

Whole body clipping may actually spread the infection to other areas of the body, and may cause trauma to the skin, spread infectious hairs to the environment, and increase stress to the cat. Infected cats should be confined to an easily cleaned area, but not isolated from human contact. People interacting with infected cats should wear gloves as well as shoes and clothing that are washable. 

Twice weekly cleaning of the environment is recommended, with special care taken to remove shed hair, followed by application of a disinfectant. Ordinary washing with laundry detergent of washable items is sufficient for disinfection; bleach and hot water have been found to be unnecessary. Since bleach is a respiratory irritant, accelerated hydrogen peroxide or enilconazole (where available) can be used in lieu of bleach on washable surfaces requiring disinfection. 

Ringworm does not "live" or "multiply" when not on a live host, unlike mildew or mold, it needs keratin (skin and hair) as a source of nutrients. Spores are easily removed by mechanical cleaning and washing. 

Prognosis:
Although feline ringworm can infect people, it is easily treated in humans, even immunocompromised ones. A ringworm infected cat needs to be treated appropriately and completely, but this infection should not be used as a reason for euthanasia in a shelter or relinquishment from a loving home. 

GENETICS

TICA Members Support Research!

TICA members Cristy Bird, Johnny Gobble, Terri Harris, Anthony Hutcherson, Mark Kantrowitz, Anthony Nichols and Frank Whittenberg Hutcherson were acknowledged in an article on feline precision medicine in the Journal of Veterinary Internal Medicine. These enthusiasts provided their cat’s DNA to the 99 Lives Consortium, a collaborative research project involving multiple laboratories around the world. 

Spearheaded by Leslie Lyons, PhD from the Department of Veterinary Medicine & Surgery at the University of Missouri, this project used whole genome sequencing of a feline patient at the university's veterinary medical center to diagnose the cause of the cat's neurological symptoms. 

A variant was identified in the gene associated with Niemann-Pick disease that was not found in any other of the 73 domestic cats and 9 wild cats in the database or 190 additionally sequenced cats of various breeds. The success of this case demonstrated that this type of precision medicine approach, just starting to be used in human medicine, is also feasible for cats.

Dr. Lyons will be at the 2019 TICA Annual in Las Vegas to discuss her current research. Consider volunteering a cheek swab from your show cat to help build the database of healthy cats for future research.

CLINICAL MEDICINE 

Talking to Your Vet About Poop by Lorraine Shelton

One of the top reasons for cat owners to visit the vet is related to litterbox issues. How can you describe what is going on at home in terms that your veterinarian will understand?

Bringing in stool samples for analysis is helpful, but often fecal consistency is an ever-changing mix of good days and bad days. By taking careful observations where changes can be interpreted in a meaningful manner.

4 main stool characteristics to be noted:
color,
consistency
contents
coating

Color:
Normal stool = medium to dark brown. Bright red streaks may indicate bleeding from the large intestine, while black or very dark red stools can be caused by bleeding in the stomach or small intestines. 

Pale colored stools can be caused by disorders of the liver, gallbladder or pancreas.

Consistency:
Solid, hard consistency, and be easy for the cat to pass. 

Often has a "cracked" or segmented appearance (like a Tootsie Roll). A soft, sausage shaped appearance could be normal for your cat.
Soft blobs, mushy pudding consistency, or fully liquid stools can be associated with parasites or other illness.

Contents:
Foreign bodies that your cat has ingested, undigested food, rice-like segments from tapeworm infection, or long white strands from roundworm infection.

Coating:
Mucus coating, is an important observation that may indicate inflammation of the colon.

Keep in mind that temporary changes in stool may occur due to minor issues like diet changes or stress, but if abnormalities continue, consult your vet. 

WILD CATS

Decoding Tiger Attacks by Lorraine Shelton

A recent article on tiger behavior, published in the journal Nature Communications, reads like an episode of Criminal Minds! The research suggests that a geographic profiling tool used to catch serial criminals could theoretically be used to help reduce the number of tiger encounter incidents by identifying high risk areas for attacks and intervening before they occur. 

Dr. Matthew Struebig at the University of Kent and Dr. Freya St. John at Bangor University determined that the frequency of tiger attacks on livestock and people can be predicted from a complex analysis of over a decade of data on tiger encounters combined with interviews of local Sumatran people on their attitudes toward tigers, including their spiritual beliefs about them. 

Tigers can pose a threat to people and lifestock, but since tigers are on the brink of extinction due to deforestation and persecution finding a way that they can coexist with people is important. If resources for intervention can be targeted to high risk areas, it can reduce the risk of these incidents, and therefore minimize the number of retaliatory actions on tigers by affected communities. 

They concluded that pre-emptive interventions using this predictive model could have prevented up to 51 percent of attacks on livestock and people, potentially saving 15 tigers. 

FELINE BEHAVIOR 

Feline Research Facility Sets New Standard

by Lorraine Shelton

"Many facilities have come a long way in making research conditions more humane for the animals, but they still involve small enclosures without a lot of enrichment," says Amy Fischer of the Department of Animal Sciences at University of Illinois and lead investigator of the study published in the Journal of Feline Medicine and Surgery . "We wanted to make our cats' environment much more stimulating." These researchers created a unique study environment designed to mimic a more typical home environment for the cats, in order to study the efficacy of a new feline contraceptive vaccine. The cats became much more friendly and adoptable with the changes to their environment.

For years researchers have searched for ways to prevent unwanted feline pregnancies in community cats, as traditional spay and neuter services are expensive, since they can only be performed by licensed veterinarians. An injectable contraceptive vaccine, was shown to be effective in laboratory-raised cats, but it was unknown how effective the vaccine would be in "the real world". 

The 35 cats in the study, at high risk for euthanasia in local shelters, were housed in a large, open building, with an attached quarter-acre outdoor enclosure. The indoor environment had scratching posts, furniture, toys, and hiding places. Volunteers, played with the cats and trained them to feel more comfortable with veterinary procedures, such as blood draws and ultrasounds. Thirty female cats, about half treated with the vaccine and half untreated, were allowed to intermingle and breed with five intact males as they would under natural conditions. 

Unfortunately, 60% of vaccinated females became pregnant within a few months of receiving the vaccine, with an additional 10% pregnant within the year. 

Although the outcome was disappointing, valuable lessons were learned on creating a better environment for studying cats. These cats, deemed unadoptable at the local shelters prior to the study, became so well socialized that they were easily placed into good homes at the end of the study.