Pulmonary Nodule Caused by Dirofilaria immitis in a Laboratory Rabbit (Oryctolagus cuniculus domesticus)

Spinal Lymphoma and Pulmonary Filariasis in a Pet Domestic Rabbit (Oryctolagus Cuniculus Domesticus)

“…Experimental infection of rabbits with D. immitis and spontaneous filarid infection found in a laboratory rabbit used in an unrelated study have been described previously. 11,13 However, the spontaneous filarid infection in a laboratory rabbit was reported more than 25 years ago in Japan and, to the authors' knowledge, has not been reported since that time. 11 The morphology of the degenerate heartworm in the current case is consistent with an immature female L5 stage of D. immitis.…”

“…11,13 However, the spontaneous filarid infection in a laboratory rabbit was reported more than 25 years ago in Japan and, to the authors' knowledge, has not been reported since that time. 11 The morphology of the degenerate heartworm in the current case is consistent with an immature female L5 stage of D. immitis. Histomorphologic characteristics of the filarid infection in the rabbit are almost identical to those of D. immitis described by previously.…”

“…2,5,[9][10][11][12][13][14][15][16] Features differentiating the filarid in the rabbit in the current case from other filarid nematodes include size, the prominent r coelomyarian striated muscle, and the 2 prominent lateral cords with cuticular lateral ridges. Based on an excellent review of the diagnostic features of filarids in tissue section, other filarid parasites, including Dirofilaria tenuis, Dirofilaria repens, Dirofilaria ursi, Oncocerca spp., and Brugia spp., could be eliminated from consideration based on clearly identifiable differences from the parasite described herein.…”

“…1 The identity of this filarid as D. immitis using PCR analysis was unable to be conclusively confirmed, but much of the human and veterinary literature has used less stringent histomorphologic characteristics to diagnose D. immitis. 2,4,5,[9][10][11][12][13][14][15][16] Given the geographic location of this rabbit and the endemic prevalence of heartworm disease, the most likely diagnosis of the filarid is D. immitis.…”

“…Trichrome staining was used to better delineate parasite morphology based on a previous report using azantype stains for parasite identification. 11 Three transverse sections of the parasite were seen that varied from 170 mm to 220 mm in diameter, had a thin smooth amphophilic outer cuticle, and 2 internal lateral ridges. The filarid also had very prominent, thick, striated, eosinophilic coelomyarian muscle that was divided into 2 segments by lateral cords.…”