Intralesional amphotericin B in a cat with cutaneous protothecosis

A domestic cat was presented with nodular lesions on the nose/muzzle and pinnae. Protothecosis was diagnosed through cytological and histopathological examination, and culture. Molecular identification confirmed Prototheca wickerhamii infection. Intralesional application of amphotericin B in conjunction with oral terbinafine resulted in a significant reduction of the nasal lesion and complete resolution of the pinnal lesion, without adverse effects.

Neurologic and cutaneous infection by Clostridium piliforme in a kitten with systemic Tyzzer disease

Tyzzer disease (TD) is a highly fatal condition of animals caused by Clostridium piliforme and characterized pathologically by enteritis, hepatitis, myocarditis, and occasionally encephalitis. Cutaneous lesions have been reported only rarely in animals with TD, and infection of the nervous system has not been described in cats, to our knowledge. We describe here neurologic and cutaneous infection by C. piliforme in a shelter kitten with systemic manifestations of TD and coinfection with feline panleukopenia virus. Systemic lesions included necrotizing typhlocolitis, hepatitis, myocarditis, and myeloencephalitis. The cutaneous lesions consisted of intraepidermal pustular dermatitis and folliculitis, with necrosis of keratinocytes and ulceration. Clostridial bacilli were identified within the cytoplasm of keratinocytes by fluorescence in situ hybridization, and a PCR assay was positive for C. piliforme. C. piliforme can infect keratinocytes leading to cutaneous lesions in cats with the location suggesting direct contact with contaminated feces as a route of infection.

Protothecosis in Dogs and Cats-New Research Directions

Protothecosis refers to disease of humans and animals caused by infection with fungus-like, colourless microalgae of the genus Prototheca. Although protothecosis remains an uncommon infection, increasing numbers of human and animal cases are being diagnosed worldwide. This review summarises major new findings in basic science (sequencing analyses of sterol 14α-demethylase (CYP51/ERG11) genes and organelle genomes of Prototheca wickerhamii) to elucidate taxonomic features of this pathogen. Furthermore, this review updates and summarises the clinical features, diagnosis and treatment of protothecosis in dogs and cats. This content of this review is based on information presented at the medical phycology symposium held in the 20th Congress of the International Society for Human and Animal Mycology ( https://www.isham.org/ ).

Comparison of livestock-associated and community-associated Staphylococcus aureus pathogenicity in a mouse model of skin and soft tissue infection

Industrial hog operation (IHO) workers are at increased risk of carrying Staphylococcus aureus in their nares, particularly strains that are livestock-associated (LA) and multidrug-resistant. The pathogenicity of LA-S. aureus strains remains unclear, with some prior studies suggesting reduced transmission and virulence in humans compared to community-associated methicillin-resistant (CA-MRSA) S. aureus. The objective of this study was to determine the degree to which LA-S. aureus strains contracted by IHO workers cause disease relative to a representative CA-MRSA strain in a mouse model of skin and soft tissue infection (SSTI). Mice infected with CC398 LA-S. aureus strains (IHW398-1 and IHW398-2) developed larger lesion sizes with higher bacterial burden than mice infected with CA-MRSA (SF8300) (p < 0.05). The greatest lesion size and bacterial burden was seen with a CC398 strain that produced a recurrent SSTI in an IHO worker. The LA-S. aureus infected mice had decreased IL-1β protein levels compared with CA-MRSA-infected mice (p < 0.05), suggesting a suboptimal host response to LA-S. aureus SSTIs. WGSA revealed heterogeneity in virulence factor and antimicrobial resistance genes carried by LA-S. aureus and CA-MRSA strains. The observed pathogenicity suggest that more attention should be placed on preventing the spread of LA-S. aureus into human populations.

Severe Persistent Orf in Young Goats

Orf (contagious ecthyma) is a viral disease of small and wild ruminants, humans, and less frequently other species. In sheep and goats, the disease is characterized by the formation of vesiculo-proliferative lesions in the skin of lips and nostril. Here, a form of generalized orf in 16 goat kids from 2 different locations in west Texas is described. The disease was characterized by multifocal, severe, proliferative dermatitis that persisted from about 2 months of age until the goat kids were euthanized 3 months later. All affected goats were Boer or Boer crosses under 1 year of age. The mean immunoglobulin concentration in sera of affected goats was elevated compared with healthy control goats. Severe to moderate lymphadenomegaly of the nodes draining the areas of the skin affected with orf lesions was present in all 16 goat kids. Suppurative arthritis, chronic fibrinous pneumonia, and premature thymic involution were found in 3, 5, and 7 of the goat kids, respectively. The skin lesions of 3 goat kids were infested with larvae of the opportunistic black garbage fly ( Ophira sp.). The orf virus was identified in skin lesions by isolation in Marbin—Darby ovine kidney cells, electron microscopy, and amplification of viral DNA by polymerase chain reaction. The orf virus was not detected in peripheral blood or lymph node mononuclear cells of any of the goats. Cross-neutralization experiments showed that an ovine orf virus antiserum raised in sheep was more effective in neutralizing a sheep orf virus isolate than a caprine orf virus isolate. The clinical and epidemiological characteristics of these orf cases may be the result of susceptibility factors within some individuals of the Boer breed of goats.

[Animal Staphylococcus felis with the potential to infect human skin]

INTRODUCTION

Breaking interspecies barrier by microorganisms has become in the recent years an alarming phenomenon that threatens public health worldwide. An important potential interspecies transmission risk factor is close contact animal-human including occupational exposure of pet breeders and veterinarians.

MATERIAL AND METHODS

The features of Staphylococcus felis ZMF 13 strain isolated from a swab from a cat's wound connected with potential pathogenicity were investigated. Results: The virulence factors of strain found were hydroxamate siderophores, production of invasins - intracellular proteolytic and lipolytic enzymes and the ability of biofilm production. The ability of bacteriocin-like substance production was also observed. The substance has an antagonistic activity against bacteria belong to physiological flora of the human skin which may be important in breaking the colonization resistance of human organism. Although the strain of S. felis ZMF 13 was methicillin-susceptible it demonstrated the constutive type of MLSB resistance mechanism. The genes ermA, msrB, linA connected with macrolide, lincosamides and streptogramin B resistance were detected.

CONCLUSIONS

The current evidence suggest that Staphylococcusfelis has a number of features that can be crucial in its potential interspecies transmission.

Vaccination against cutaneous and mucosal papillomavirus in cattle

Viruses are responsible for approximately 15% of human cancer worldwide. Human papillomavirus and hepatitis B virus are the recognized agents of cervical and liver cancer, respectively, which together constitute 80% of all virally induced cancers. If measures could be found to bring viral infection under control, a great proportion of human cancer would be greatly reduced. Experimental vaccines are being developed against papillomavirus. In principle two different types of vaccine can be envisaged: prophylactic vaccines that would elicit virus-neutralizing antibodies and would prevent infection and therapeutic vaccines that would induce regression of established lesions before progression to malignancy took place. The research on vaccines against human papillomavirus is hampered by the difficulties encountered in growing the virus in tissue culture and by the unacceptable nature of experimentation in humans. Effective vaccines, both natural and genetically engineered, have been developed against bovine papillomavirus and cottontail rabbit papillomavirus. The success obtained with the animal models supports the optimistic prediction that in the relatively near future vaccines will be available against the most problematic or potentially dangerous forms of papillomatosis in humans.

Practical cytology for inflammatory skin diseases

Cytology is the most common and immediately informative diagnostic tool in the practice of dermatology. It is simple to perform and requires equipment usually already present in most practices such as a microscope and slides, cotton-tipped applicators and stains. Cytology interpretation is also easily self taught. With little practice the practitioner can easily become familiar with sample interpretation from inflammatory lesions; including recognition of bacteria, yeast, dermatophyte spores and hyphae, deeper fungal elements and parasites. Additionally, the practitioner should become familiar with the variety of inflammatory cells seen with these conditions, as well as keratinocyte morphology. This article provides an overview and the initial steps on how to become a more proficient cytologist in practice.

Topics in pediatric dermatology

Skin conditions of puppies and kittens are often infectious, such as ectoparasites or dermatophytosis. Hereditary and congenital skin problems are often detected at an early age. Young animals may be more prone to toxicity from medications, and labels should be read carefully for age limits. Husbandry factors, including nutrition, ectoparasites,temperature and humidity, cleaning products, and bedding, should be considered. Fleas are still a common problem despite recent improvements in flea control and can be debilitating in young animals because of blood loss.

Cutaneous acariasis in the African clawed frog (Xenopus laevis)

Increased mortality was observed in a single colony of 50 Xenopus laevis. The frogs were used as oocyte donors in developmental biology studies. Necropsy findings included dermal erythema and petechiation consistent with red leg syndrome; dermal ulcerations and white, filamentous growths on the skin were consistent with Saprolegnia sp. Microscopic evaluation of the skin and fungus revealed an astigmatid mite similar to those of the genus Rhizoglyphus. The mite was also found in the water and the biological filter of the tanks housing the frogs. This mite is considered not to be a parasite of X. laevis; instead, it feeds off moss, fungi, and detritus. Subsequent evaluation of the sphagnum moss used for shipping the frogs from the supplier revealed the same mite in the moss. Our hypothesis is that the mite was introduced into the tank with the shipment of new frogs in sphagnum moss. The mites lived within the biological filter, and were only found after the growth of Saprolegnia sp. attracted the mites to the frogs. Laboratory animal care and veterinary personnel should consider non-pathogenic species of mites in the differential diagnosis of acariasis in Xenopus frogs.

Topical tea tree oil effective in canine localised pruritic dermatitis--a multi-centre randomised double-blind controlled clinical trial in the veterinary practice

Tea tree oil, a volatile oil, is well known for its broad antibacterial and antifungal activity. A standardised and stabilised 10% tea tree oil cream was tested against a commercial skin care cream (control cream) in the management of canine localised acute and chronic dermatitis. Fifty-seven dogs with clinical manifestations of mostly pruritic skin lesions or alterations, skin fold pyodermas and other forms of dermatitis, corroborated by predominantly positive fungal and bacterial skin isolates, were enrolled by seven practising veterinarians and randomly allocated to two study groups (28:29) and were treated twice daily with a blinded topical preparation. After 10 days of treatment, success rates of 71% for the tea tree oil cream and 41% for the control cream (over-all efficacy documented by the veterinary investigator) differed significantly (p = 0.04), favouring tea tree oil cream treatment. Accordingly on day 10, the tea tree oil cream caused significantly faster relief than the control cream (p = 0.04) for two common clinical dermatitis signs, pruritus (occurring in 84 % of dogs) and alopecia. Only one adverse event was reported in the tea tree oil group (suspected not to be causally related to the study drug) and none in the control cream group. The tested herbal cream appears to be a fast-acting safe alternative to conventional therapy for symptomatic treatment of canine localised dermatitis with pruritus.

Clinicopathologic Findings Associated withLagenidiumsp. Infection in 6 Dogs: Initial Description of an Emerging Oomycosis

An oomycotic pathogen in the genus Lagenidium was isolated from tissues obtained from 6 dogs with progressive cutaneous disease. Initial clinical findings in 5 dogs included multifocal cutaneous lesions, subcutaneous lesions, or both associated with regional lymphadenopathy: the 6th dog initially was presented for evaluation of mandibular lymphadenopathy. Cutaneous lesions were ulcerated, exudative regions (often with necrosis and draining tracts) or multiple firm dermal or subcutaneous nodules. Two dogs subsequently developed hemoabdomen from great vessel rupture and died acutely. Four dogs were euthanized because of progression of subcutaneous lesions or lymphadenopathy. On postmortem examination, regional granulomatous lymphadenitis was found in all 6 dogs, great vessel invasion in 3 dogs, pulmonary lesions in 2 dogs. ureteral obstruction in 1 dog, mediastinal lymphadenitis in 1 dog, and hilar lymphadenitis with invasion of the distal esophagus and trachea in 1 dog. Histologically, lesions were similar to those associated with pythiosis and zygomycosis and were characterized by severe eosinophilic granulomatous inflammation (often with numerous large multinucleated giant cells) centered around broad (7-25 micro), infrequently septate hyphae. Immunoblot analysis of the serologic response of 4 dogs to a soluble mycelial extract of Lagenidium giganteum indicated that each dog's serum recognized at least 10 different antigens of L. giganteum. Culture of infected tissues yielded rapid growth of colorless to white submerged colonies. Microscopically, mature hyphae in culture were broad (25-40 micro), segmented, and occasionally branching and produced motile laterally biflagellate zoospores in water culture. This report is the 1st description of infection caused by an oomycete other than Pythium insidiosum in any mammalian species.

Immunotherapy for treatment of multicentric cutaneous pythiosis in a dog

A 4-year-old Labrador Retriever was referred for evaluation of 2 ulcerative nodular cutaneous lesions. One lesion was located on the medial aspect of the right carpus; the other was located on the medial aspect of the left tarsus. The dog had spent its entire life in the southeastern part of the United States and approximately half of its time outdoors with free access to a nearby lake. Histologic examination of full-thickness wedge biopsy specimens from both lesions revealed severe, multifocal, puruloeosinophilic to pyogranulomatous deep dermatitis with intralesional filamentous structures, fibroplasia, and neovascularization. Examination of sections stained with Gomori methenamine silver stain revealed a moderate number of wide, bulbous, irregularly septate, branching hyphae. Results of an immunodiffusion test and an ELISA for anti-Pythium insidiosum antibodies were positive. Amputation was eliminated as a treatment option because lesions involved 2 limbs. Long-term systemic antifungal treatment was also rejected because of the cost, lack of therapeutic effect in many cases, and potential for adverse effects. The dog was treated with 2 doses of an anti-P insidiosum vaccine administered 2 weeks apart. One month later, the lesions were nearly completely healed, and values obtained via the immunodiffusion test and ELISA had decreased. Results of the immunodiffusion test and ELISA were negative 1 year later, and the dog had not had any recurrences.

Antagonistic activity of Aeromonas media strain A199 against Saprolegnia sp., an opportunistic pathogen of the eel, Anguilla australis Richardson

A bacteriocin-like inhibitory substance (BLIS) produced by Aeromonas media strain A199 inhibited the growth of Saprolegnia sp. in vitro, an opportunistic pathogen isolated from affected eels, Anguilla australis (Richardson). The presence of BLIS in solid media inhibited the growth of the vegetative state of the aquatic mould as well as the germination of cysts. Uninhibited growth was, however, observed in the presence of inactive BLIS, suggesting that the in vitro antagonism derived from the BLIS of A199. In four independent in vivo tank observations of fish affected with saprolegniosis, the daily addition of A199 to tank water contributed to the subsequent swift recovery of affected hosts from invasion by this opportunistic pathogen.

Cutaneous lesions

Although not a substitute for histologic examination, lumps, bumps, and lesions of the skin and subcutis readily lend themselves to cytologic examination via FNB, fine-needle nonaspiration biopsy, imprinting, or scraping of lesions. These techniques are used to obtain cells that can be examined by a clinical pathologist or cytologist to provide a diagnosis, decide a course of therapy, or offer a prognosis. Although histologic and cytologic examinations do not always agree, many times there is excellent correlation between the two disciplines. There are few patients with cutaneous lesions that would not benefit from cytologic examination of their lesion.

Nonhealing subcutaneous wounds in the cat and proposed surgical management techniques

Nonhealing wounds in cats are a source of frustration for veterinarians and pet owners alike. These wounds are known for their insidious onset and tendency to recur after standard surgical closure. The presence of a feline wound that fails to heal in the face of appropriate therapy should initiate an extensive diagnostic evaluation for an etiologic agent. Initially animals should be screened for causes of immunosuppression or systemic disease. The local wound environment should then be evaluated through a combination of wound exploration, cytology, histopathology and tissue culture for evidence of a foreign body, neoplasia, or other less common etiologies of these wounds. Many of the less common etiologic agents require specific tissue handling for successful microscopic identification and culture. It is therefore essential for veterinarians to be familiar with the various causes of nonhealing wounds in cats so that laboratories can be alerted of the need for specific diagnostic techniques. Recent surgical and medical advances have the potential to facilitate the successful treatment of these wounds. With improved veterinary awareness of the potential etiologies of nonhealing wounds in cats and improved medical and surgical management techniques many wounds can now successfully be treated.

Review cutaneous lesions of the canine scrotum

Scrotal lesions are uncommon and often present a diagnostic challenge. In the veterinary literature there are no texts devoted to this subject. This study reviews and illustrates canine scrotal lesions following an aetiological layout with the aim of facilitating clinical identification and diagnosis. Infectious, immune-mediated, endocrinological and neoplastic conditions are the most commonly reported causes of scrotal lesions in the dog. They may affect the scrotum only or other parts of the body as well. The clinical presentation of the lesions, the presence of primary or secondary lesions and the presence of clinical signs of systemic disease may help in obtaining a diagnosis. In some cases further investigations are necessary to reach a definitive diagnosis. Histopathology aids in understanding pathological reactions of the scrotal skin but unfortunately this is not commonly carried out and few reports in the literature include histopathology. The list of conditions given in this review is not exhaustive and other, more rare, diseases may be encountered.

Expression of a transforming gene (E5) of bovine papillomavirus in sarcoids obtained from horses

OBJECTIVE

To determine expression of a transforming gene (E5) of bovine papillomavirus in sarcoids, other tumors, and normal skin samples collected from horses with and without sarcoids.

SAMPLE POPULATION

23 sarcoids and 6 samples of normal skin obtained from 16 horses with sarcoids, 2 samples of normal skin and 2 papillomas obtained from horses without sarcoids, and 1 papilloma obtained from a cow.

PROCEDURE

Protein was extracted from tissue samples collected from horses and incubated with agarose beads covalently coupled to Staphylococcus aureus protein A and an anti-E5 polyclonal antibody. Following incubation, proteins were eluted from the beads and electrophoresed on a 14% polyacrylamide gel and transferred to a polyvinylidene difluoride membrane. The E5 protein was detected by use of western blot analysis, using a chemiluminescence detection system.

RESULTS

All 23 sarcoids had positive results for expression of E5 protein. Quantity of viral protein appeared to vary among sarcoids. All other tissues examined had negative results for E5 protein. Highest expression for E5 protein was observed in biologically aggressive fibroblastic variants of sarcoids, compared with expression in quiescent tumors.

CONCLUSIONS AND CLINICAL RELEVANCE

This study documented that activation and expression of the E5 gene is evident in sarcoids obtained from horses. These data support the conclusion that infection with bovine papillomavirus is important in the initiation or progression of sarcoids in horses. Treatment strategies designed to increase immune recognition of virally infected cells are warranted.

[Zoonoses and dermatoses: the veterinarian's point of view]

Pets live more and more in contact with humans. It is then usual to observe occasionally cutaneous problems transmitted from the animal to the man. The most important risk of dermatozoonosis is dermatophytosis because of a lot of dogs or cats seem to be asymptomatic carriers. Pruritus in owners of pets developing a "mange" is also a complaint very often evokated during the veterinary consultation. Even if this problem could be sometimes very spectacular, in the majority of the cases, all the symptoms in humans disappear with the management of the skin disease in pets. A review of the animal dermatosis presenting a risk for the humans is proposed in the present paper.

New drugs in veterinary dermatology

This article discusses several different new drugs currently being used in dermatology. Most of the drugs discussed showed some promise as being a useful therapy in veterinary medicine, but a few have questionable efficacy (nonsedating antihistamines). The majority of these drugs have not had any pharmacokinetic or clinical trials conducted on them in small animals. Hopefully, in the future, more studies are funded so that we can determine the clinical therapeutical efficacy and appropriate doses for these drugs.

Infectious dermatitis in a ball python (Python regius) colony

Seven wild-caught ball pythons (Python regius), including six gravid females and one male, were obtained from Africa and were housed in a government animal facility in Research Triangle Park, North Carolina. Upon arrival, the snakes were found to be infested with ticks (Aponomma latus), which were manually removed. Four weeks following arrival, vesicular skin lesions began to appear on the snakes. Despite treatment of all affected female snakes with amikacin (5 mg/kg i.m., every 3 days) and cefotaxime (25 mg/kg i.m., every 3 days), the condition progressed and five of the female snakes died 7 wk after arrival. The remaining male and one female improved after an increase in environmental temperature, with ecdysis followed by healing. Physiologic stress, ectoparasites, and shipping may have predisposed the snakes to sepsis.

Infectious diseases and parasites of ratites

This article discusses infectious and parasitic disease conditions in the three ratite species. Diseases and parasitic conditions are reviewed in relation to etiology, transmission, pathology, diagnosis, treatment, and prevention. To ensure optimum reproduction and growth of birds on large production units, a veterinarian must understand management in relation to biosecurity and disease problems.

Secondary immunodeficiency in dogs with enteric, dermatologic, infectious or parasitic diseases

A group of 238 dogs with various infectious and parasitic disease, in which suppressed activity of the immune system could e presumed, was examined using a set of immunological methods. The frequency and depth of immunosuppression and its association with certain infectious or parasitic disease were determined. Marked immunosuppression was found 62 (26%) of the dogs examined. Dogs with distemper, parvovirosis and German Shepherd dog pyoderma (GSP) were the most severely impaired. Dogs in acute phases of distemper or parvovirosis had decreased numbers and activity of lymphocytes and decreased immunoglobulin levels. Dogs with GSP had some of the following immunologic symptoms: inhibition of phagocytosis, reduced activity of lymphocytes, decreased levels of haemolytic complement and increased levels of immunoglobulin and lysozyme. A persistent immunosuppression was found in 12 dogs. These dogs were diagnosed with deep pyoderma, giardiasis, dermatophytosis or neoplasms. Although samples were not taken before the clinical diseases appeared, it can be presumed that some diseases caused immunosuppression (distemper or parvovirosis), and for other diseases immunosuppression was a predisposing factor (dermatophytosis, giardiasis and possibly GSP).

Pathology of skin diseases in crocodiles

OBJECTIVE

To establish which skin diseases occur in crocodiles, particularly those on farms, to indicate the relative frequency of each particular disease and to provide information on pathogenesis, especially in regard to lesions with two or more pathogens present.

DESIGN

A gross and microscopic retrospective (period of 1989 to 1995) and current (1996 to 1997) examination of skin lesions in crocodiles in Queensland and the Northern Territory.

RESULT

Skin lesions were obtained from crocodiles on nine farms, from a group of experimental animals and from one adult found dead in the wild. A total of 203 lesions from 180, mostly young, crocodiles was examined; 119 lesions were from retrospectively examined cases and 84 were recent. The relative frequencies of four presumed primary pathogens in lesions were Dermatophilus sp 28.1%, fungi 14.8%, poxvirus 3.4% and probable Mycobacterium sp 2.5%. In addition, other bacteria of unknown significance were present in many lesions, and there was one case of presumed Paratrichosoma crocodilus infection. In 32.5% of lesions, multiple pathogens were identified.

CONCLUSION

Dermatophilosis is the most common and probably the most important skin disease of crocodiles in Australia, but it is frequently complicated by concurrent infection with fungi or other microorganisms.

Cutaneous protothecosis in a dog

A dog was infected systemically with Prototheca wickerhamii but showed only cutaneous protothecosis. The lesions appeared progressively and consisted of non-pruritic scrotal swelling and ulceration, cutaneous nodules, crusty ulcerative lesions over the trunk and serous rhinitis. The diagnosis was based on skin biopsy findings and specific culture. Microscopic examination revealed a diffuse pyogranulomatous dermatitis and numerous protothecal organisms of different sizes within the cytoplasm of phagocytic cells. Treatment with oral ketoconazole for six months resolved all the clinical signs except the scrotal granuloma which, although it was significantly reduced, had to be removed surgically. However, after five months the condition returned.

The association between Amblyomma variegatum and dermatophilosis: epidemiology and immunology

A close association was found between infestation with Amblyomma variegatum and the occurrence of dermatophilosis on cattle on the coastal Plains of Ghana. Animals belonging to breeds traditionally regarded as more susceptible to the disease also tended to carry higher tick burdens. The basis of the association between infestation with this tick and the occurrence of dermatophilosis would appear to involve tick-induced immunosuppression.

Artificial transmission of Bolo disease in woolled sheep and attempted characterisation of the causative unclassified Corynebacterium sp

Bacterial isolates (n = 38) previously cultured from sheep with Bolo disease were compared bacteriologically with known Corynebacterium spp. and Actinomyces spp. The isolates did not conform to any previously described species but closely resembled C. pseudodiptheriticum and C. urealyticum. More comprehensive tests are needed to classify this Corynebacterium sp. Bacterial cultures of this unclassified Corynebacterium sp. were used artificially to induce Bolo disease in Dohne Merino sheep (n = 20). Ten sheep were kept at Middelburg in the Cape Midlands (Northern Cape) under arid conditions and another 10 at Queenstown in the Eastern Cape in a more humid climate. Two suspensions containing 2.8 x 10(5) Corynebacterium sp. (inoculum A) and 2.8 x 10(9) Corynebacterium sp. (inoculum B) respectively were used to infect each sheep on 9 different sites on the skin. One sheep died during the course of the experiment. Corynebacterium sp. established itself on 81 out of 171 inoculation sites of the remaining sheep and caused typical lesions of Bolo disease, clinically and pathologically. Bolo disease lesions developed slowly over 175 days at Middelburg and 287 days at Queenstown. Weather conditions were unfavourable to the development of fleece-rot and mycotic dermatitis. No difference was seen in lesion development between rams and ewes or between sheep with 5 months' wool growth and those which were shorn before inoculation. More lesions developed with the higher concentration of inoculum B (49 sites positive) as compared to inoculum A (32 sites positive).

Overview of equine papular and nodular dermatoses

Papules and nodules are common lesions on horses and have a variety of underlying causes. This article addresses inflammatory and congenital nodules primarily, including urticaria, erythema multiforme, those nodules caused by infectious agents, epidermoid and dermoid cysts, and the uniquely equine skin tumor, the sarcoid. The eosinophilic nodules and other tumors are covered elsewhere in this issue. Diagnostic and therapeutic approaches to each of the diseases are emphasized.

Nephrotoxicosis associated with topical administration of gentamicin in a cat

A 4-year-old cat was referred for treatment of a large, open wound. The wound had been lavaged twice, approximately 12 hours apart, with approximately 10 ml of 5% gentamicin solution prior to referral, because of infection caused by Pseudomonas spp. Results of initial serum biochemical analyses were within reference ranges, and the cat was anesthetized for surgical wound debridement and closure. Two days later, the cat was azotemic (SUN concentration, 113 mg/dl; serum creatinine, concentration, 9.8 mg/dl) and had a urine specific gravity of 1.008. Granular casts were seen in the urine. The azotemia became more severe over the next 2 1/4 hours, despite treatment for acute renal failure, and the cat was euthanatized. Severe acute proximal tubular necrosis, consistent with gentamicin-induced nephrotoxicosis, was diagnosed histologically. Retrospectively, serum samples obtained for biochemical analyses were assayed for gentamicin concentration. Serum concentration of gentamicin 8 hours after topical lavage was 58.07 micrograms/ml. This was approximately 6 times greater than the desired peak concentration for gentamicin and suggested that gentamicin had been absorbed systemically following topical application.

In vitro inhibition of some gram-positive bacteria by Staphylococci and Aerococcus viridans of porcine origin

Nine coagulase-negative Staphylococci and Aerococcus viridans were tested for bacterial antagonism. Seven of the nine of the coagulase-negative Staphylococci and Aerococcus viridans inhibited the growth of four Staph. hyicus, three Staph. aureus strains and some other Gram-positive bacteria, including Streptococcus group A and D, Corynebacteria, but none of the Gram-negative and yeast was inhibited on agar media. There was also production of inhibitory substances in different types of liquid media but no antagonistic activity was observed on Millipore membrane. The inhibition was not due to the pH change of media in which the producers were grown, but due to production of inhibitory substances tentatively classed as antibiotics.

Treatment of opportunistic mycobacterial infections with enrofloxacin in cats

Marked improvement was observed in the condition of 6 cats with opportunistic mycobacterial infections during treatment with enrofloxacin, a fluoroquinolone antibiotic. Complete remission was achieved in 3 cats after 3 to 7 weeks of treatment. The other 3 cats were euthanatized after 1 to 2 weeks of treatment for reasons not related to the treatment. Lesions did not recur within the follow-up period, which ranged from 9 to 16 months. Treatment of opportunistic mycobacterial infection in cats is complicated because many mycobacteria are resistant to antituberculosis drugs, which also can be toxic to cats, and because results of susceptibility testing with other antimicrobials do not always correlate with clinical response. Often, neither satisfactory nor long-term response is observed in cats treated surgically or with the antibiotics currently recommended. These findings suggested that enrofloxacin is effective in the treatment of infections caused by Mycobacterium smegmatis and M fortuitum var fortuitum in cats.

Relationship between the immune response of sheep and the population dynamics of bacteria isolated from fleecerot lesions

In sheep wetted by rain, proliferation of bacteria in the skin-fleece microenvironment invariably discolours the fleece and causes a dermatitic condition known as fleecerot. The changes in population dynamics of fleece bacteria were analysed by carrying out skin washings at randomly selected sites on the back of sheep before, and at 48 h and 96 h after exposure to rain. Gram-positive rods belonging to Bacillus species (10(2)-10(4) cfu/cm2) predominated in dry fleece. Gram-positive cocci (e.g. Micrococcus and Staphylococcus species) as well as Gram-negative rods (pseudomonads) were also present but in lower abundance (less than 10(2) cfu/cm2). Fleece bacterial populations generally increased in numbers during the first 24-48 h of wetting. By 96 h however, skin washings showed a preponderance of Pseudomonas aeruginosa (10(4)-10(6) cfu/cm2) and to a lesser extent, pigmented Micrococcus species. Growth of fleece bacteria was associated with a characteristic green or yellow/orange staining of fleece. Fewer species of bacteria were isolated from sheep showing green staining while those animals with yellow/orange discolourations appeared to have a more mixed microflora composition. The predominance of P. aeruginosa in the wet fleece of sheep displaying either green or yellow/orange bacterial stain, was accompanied by a significant serological response against this species. Since skin bacteria have never been observed to penetrate cutaneously in skin sections biopsied from fleecerot sites, it must be concluded that the sheep skin is sensitized by continuous exposure to antigens that are associated with or released by P. aeruginosa.

[Evaluation of fixed glucocorticoid-antibiotic combinations]

Fixed combinations of glucocorticoids and antibiotics are widely used for the treatment of bacterial infections because they can cause a rapid relief of the inflammatory symptoms. However, hitherto a decisive improvement of the clinical efficacy of the combination as compared to single antibiotic therapy could not be proved. Without a real clinical advantage the combined use of glucocorticoids causes severe side effects like immune suppression with increased risk of infections, gastrointestinal lesions and depression of endogenous hydrocortisone which all will occur even after short-term use and may last for several weeks. Glucocorticoids exhibit a markedly longer duration of action than antibiotics with the risk of cumulation of the glucocorticoid. Thus, there is no kinetic compatibility as it has to be claimed for a rational combination. Due to the negative risk-benefit relation the systemic use of such combinations has to be rejected. For the topical treatment of skin disorders, however, the short-term use of combinations of corticosteroids and antibiotics with comparable pharmacokinetics on the skin like aminoglycoside antibiotics can be of clinical benefit.

Pathology of the mucous coat of trout skin during an erosive bacterial dermatitis: a technical advance in mucous coat stabilization for ultrastructural examination

A fixation regime which combined cryopreservation, freeze drying and vapour fixation with osmium tetroxide, was found to preserve the mucous coat of trout skin for ambient temperature scanning electron microscopy. The regime was used to study changes to the mucous coat of trout skin during a spontaneous outbreak of "columnaris" disease--a common dermatitis of commercial salmonids associated with the bacterial pathogen Cytophaga columnaris. Infected and damaged regions of skin were covered by a mucous coat which differed from that which covered adjacent unaffected areas. In unaffected areas, the mucous coat topography was smooth and relatively featureless. In contrast, the mucous coat which covered damaged areas was fissured, cratered and contained exfoliated epithelial cells. Nevertheless, this study showed that even sites of extensive dermal ulceration, in which mucous cells had been destroyed, retained a partial mucous coat. This suggests that mucus, after secretion, flows over the skin surface, rather than functioning only near the site of production. Because of the various protective functions attributed to the mucous coat, its partial presence over areas of skin damage would contribute to defence against secondary pathogens and to the prevention of excess movement of ions and water at these sites. The technical development in mucous stabilization, described in this paper, will provide a means for examining morphological changes to the mucous coat of fish skin in response to a range of stimuli in future studies.

The occurrence of streptothricosis and its association with Amblyomma variegatum ticks in St. Lucia

Cattle, horses, sheep and goats in all areas of St. Lucia were examined to ascertain the prevalence and distribution of streptothricosis on the island and to investigate its association with the occurrence of Amblyomma variegatum ticks. Although the disease was found to occur throughout St. Lucia it was more prevalent and generally of a more severe form in areas where A. variegatum ticks are present. A tick control programme in the North of the island appeared to have resulted in a dramatic reduction in the prevalence of the disease.

Summer lesion syndrome in salmon: a retrospective study

The factors involved in the development of 'summer lesion syndrome' were studied on 13 salmon farms based in the coastal waters of the west of Ireland. The primary causal factor in the development of the syndrome appeared to be overexposure to solar ultraviolet radiation. The pathology of the condition is described, the predisposing and reinforcing factors are considered and a hypothesis for the cause of the syndrome is proposed.

Persistent cutaneous ulcers associated with feline herpesvirus type 1 infection in a cheetah

Persistent cutaneous ulcers developed in a female cheetah cub after an episode of rhinotracheitis. When they were 3 weeks old, the cub and a male littermate developed mucopurulent oculonasal discharge consistent with feline herpesvirus type 1 infection (feline viral rhinotracheitis). The male cub was weaned and its lesions resolved. The female cub remained with the dam until the cub was 3 months old, at which time plaque-like lesions developed on the eye margins and muzzle. These plaques regressed over the next month and were replaced with cutaneous ulcers ranging from 1 to 10 mm in diameter. Feline herpesvirus type 1 was isolated from biopsy specimens collected from the ulcers. Cutaneous ulcers are uncommon manifestations of feline herpesvirus infections and have not been reported in other exotic fields. A proposed susceptibility to viral infections related to low genetic diversity has been proposed in cheetahs, and may be involved in the pathogenesis of persistent herpetic ulcers.

Evaluation of vaccines against ovine dermatophilosis

Intradermal vaccination of live crude filaments (vaccine A) was compared with a vaccine (vaccine B) consisting of a 45 kD zoospore protein and mucoid material coating filaments in its ability to protect sheep from experimental Dermatophilus congolensis infection. Fourteen and 21 days after challenge, vaccine A sheep had fewer lesions (P less than 0.001) than the vaccine B sheep. The lesions on the vaccine A sheep were also less severe 14 and 21 days after challenge (P less than 0.05, P less than 0.01 respectively). In a second study, vaccine A was assessed for its ability to protect against natural challenge. Ten weeks after contact with sheep with active and generalised dermatophilosis no difference was found between the number of lesions present on the vaccine A and unvaccinated sheep and no differences were found in the number of sheep in each group with active lesions.

Skin pustules and nodules caused by Actinomyces viscosus in a horse

A 12-year-old Arabian stallion was evaluated for a refractory skin problem of 2 years' duration. Skin nodules and pustules, which would rupture, had developed over the right lumbar muscles. Anaerobic culturing from the pustules yielded Actinomyces viscosus, and histologic examination of biopsy specimens revealed globular eosinophilic structures. Concomitant treatment with isoniazid (8 mg/kg of body weight, q 24 h for 8 weeks), trimethoprim-sulfadiazine (30 mg/kg, q 24 h for 8 weeks), and sodium iodide solution (66 mg/kg, every 1, 2, or 4 weeks, for 32 weeks) resolved the condition.

Bolo disease: a bacteriological survey

A total of 718 sheep, 381 severely and 190 mildly affected with Bolo disease as well as 147 visibly unaffected animals emanating from 15 farms in the Stutterheim and Cathcart districts in the eastern Cape were subjected to bacteriological examination of skin surfaces and wool specimens. Altogether, 1,168 specimens were examined. These included skin swabs, skin scrapings and wool samples. Corynebacterium spp represented 94.4% of the primary isolates in cultures prepared from all specimens and 97.2% in those derived from skin swabs only, while a variety of other bacteria collectively constituted the remainder of primary isolates. In all, Corynebacterium spp was isolated from specimens of 94.2% of sheep severely affected with Bolo disease and from 83.7% of those mildly affected, whereas it could only be isolated from 1.36% clinically unaffected sheep. In a comparative study, swabs taken directly from the skin surface, proved to be the method of choice for the collection of specimens for bacteriological examination of Bolo disease. Using this method, Corynebacterium spp. was isolated from 98.7% of severely, and 85.3% of mildly affected sheep as well as 4% of sheep apparently unaffected by Bolo disease. The isolation of Corynebacterium spp. from skin scrapings collected from the 3 categories of affection (73.3%, 57.3% and 4% respectively) and from wool samples (52%, 41.3% and 1.3% respectively) proved these 2 methods of sampling to be less reliable. A close association has been established between the incidence of Corynebacterium spp. and the occurrence of clinical Bolo disease.