Evaluation of intravenous fluorescein in intradermal allergy testing in psittacines.

This study was designed to improve the clinical feasibility of intradermal skin testing of psittacine birds using intravenous fluorescein stain. Twenty-five healthy, anaesthetized Hispaniolan Amazon parrots (Amazona ventralis) were injected intravenously with 10 mg kg-1 fluorescein-sodium 1% followed by intradermal injections of 0.02 mL phosphate-buffered saline, histamine phosphate (1:100,000 w/v) and codeine phosphate (1:100,000 w/v) at the sternal apteria. Wheal diameters of reaction sites were measured grossly and under illumination with a Wood's lamp after 5 and 10 min. Fluorescence-enhanced injection sites were scored between 0 and 2, with 0 equivalent to normal skin and 2 equivalent to a plucked feather follicle. The presence of a fluorescent halo around intradermal injections was also recorded. Under Wood's light illumination at 10 min, histamine and saline were evaluated as positive and negative controls, respectively, based on a positive test having a halo and a score of 2. Sensitivity and specificity were each 76% for halo, 84 and 42% for score and 64 and 77% for combination of score and halo, respectively. Further, mean histamine reactions were significantly larger than codeine phosphate and saline (8.8 +/- 0.4 mm; 7.2 +/- 0.3 mm; 5.9 +/- 0.6 mm); however, this finding was not consistent in individual birds. Wheal size, halo presence and score were affected by site location independent from the injected compound. Intravenous fluorescein improved the readability of avian skin tests; however, the compounds tested raised inconsistent reactions in wheal size, score or halo presence. The compound-independent site effect raises concern on the validity of avian skin testing and warrants investigation of other techniques such as in vitro allergy testing. Based on our findings, intradermal allergy testing in psittacines with or without fluorescein is unreliable and cannot be recommended for practical clinical use.

Experimental Reproduction of Feline Mycobacterium fortuitum Panniculitis.

Resumen- Con el fin de lograr un modelo experimental de la infección por Mycobacterium fortuitum, causante de paniculitis en condiciones naturales en el gato, se inoculóM. fortuitum en el cojinte plantar de ratones o en el tejido adiposo inguinal de conejos y gatos. Los ratones manifestaron una dermatitis crónica y una linfadenitis granulomatosa necrotizante con localizatión intracelular del microorganismo. Los conejos manifestaron inflamaciones granulomatosas supurativas necrotizantes con microrganismos en vacuolas adiposas rodeadas por heterófilos macrófagos epitelioides y/o zonas de necrosis. Los cinco gatos adultos y una de las tres crias mostraron fistulas supurativas, úlceras puntuales o nódulos en el paniculo adiposo de la zona inguinal. La lesión en la región inguinal de estos seis animales consistia en una paniculitis granulomatosa; las otras dos crias presentaban una paniculitis piogranulomatosa necrotizante. Se identificaron bacilos en los cortes histológicos teñidos con Hematoxilina y Eosina en cuatro gatos adultos y en una de las crias. Se aislóMycobacterium fortunitum a partir del tejido adiposo en todos los gatos adultos y en una de las tres crias. La inoculación de 1.4 × 1010 M.fortuitum en el tejido adiposo subcutáneo inguinal en los gatos con grandes masas grasas en esas zonas causó una infección microbacteriana idéntica a la enfermedad felina en condiciones naturales. [Lewis, D. T., Hodgin, E. C, Foil, C. S., Cox, H. U., Roy, A. F., Lewis, D. D. Experimental reproduction of feline Mycobacterium fortuitum panniculitis. (Reproductión experimental de la paniculitis felina por Mycobacterium fortuitum). Abstract- In order to establish an animal model of the naturally occurring feline Mycobacterium fortuitum panniculitis an inoculum of M. fortuitum organisms was injected into the hindlimb footpad of mice or subcutaneous fat of the inguinal area of rabbits and cats. Mice developed chronic dermatitis and necrotizing granulomatous lymphadenitis with intracellular localization of the organism. Rabbits developed necrotizing suppurative granulomatous inflammation with organisms in heterophil-lined fat vacuoles, epithelioid macrophages and/or necrotic areas. All five adult cats and one of three kittens developed draining tracts, punctate ulcers or nodules in the panniculus adiposus of the inguinal area. A pyogranulomatous panniculitis characterized the inguinal region in these six animals; a necrotizing pyogranulomatous panniculitis was present in the remaining two kittens. Rod-shaped bacilli were present on hematoxylin and eosin stained tissue sections in four adult cats and one kitten. Mycobacterium fortuitum was isolated from the inguinal subcutaneous fat in all five adult cats and one of three kittens. Injection of 1.4 × 1010 M. fortuitum organisms into the subcutaneous fat of the inguinal area of cats with extensive inguinal fatpads produced a mycobacterial infection identical to the naturally occurring feline disease.