Oculosystemic pneumocystosis in 2 sibling Chihuahuas

Abstract

Sibling female and male Chihuahuas were evaluated for a 9-month history of tachypnea that failed to respond to fenbendazole, doxycycline, amoxicillin-clavulanate, and prednisone. Physical examination identified tachypnea, hyperpnea, and harsh bronchovesicular lung sounds. Fundic examination disclosed diffuse chorioretinitis, manifested as multifocal chorioretinal granulomas in the female dog and occasional chorioretinal scars in the male dog. Thoracic radiographs indicated moderate to severe interstitial to bronchointerstitial infiltrates in both dogs. Serum and urine antigen and antibody testing in the female dog failed to identify infectious agents, but cytologic assessment of hepatic lymph node, liver, and splenic aspirates identified Pneumocystis trophozoites. Infection was confirmed in both dogs by 28S rRNA PCR sequencing from multiple tissue samples.The female dog responded well to trimethoprim-sulfamethoxazole, but the male dog was euthanized because of liver failure, presumably related to antimicrobial treatment.

Meta-Analysis and Systematic Literature Review of the Genus Pneumocystis in Pet, Farm, Zoo, and Wild Mammal Species

“…Members of the Carnivora and Perissodactyla orders showed more high-grade than low-grade infection levels. Indeed, many case reports on severe Pneumocystis pneumonia in dogs [39,40,42,44,[48][49][50][51][52][53][54][55][56][57]59,[61][62][63]66,67] and horses [101,103,[107][108][109][110] have been published. In three out of four ICs of Pneumocystis infection levels in the Pilosa order, high-grade infections were described [37,78,111].…”

“…These ICs covered the mammalian species of goat [12], llama [15], domestic pig [18,25,26,29], dog [40,42,44,48,55,57,[61][62][63], horse [25,98,99,101,103,106,107,109,110], and white-eared marmoset [37]. The consistency of the lungs was mainly described as firm or consolidated with no tendency to collapse [12,15,18,25,26,40,44,48,53,55,57,61,98,99,102,103,106,107,109,110]. In single cases, the lungs were associated with the attributes "rubbery" [26,44,48,62]...…”

“…In single cases, the lungs were associated with the attributes "rubbery" [26,44,48,62], "meaty" [25,99,101,103,107] or "hepatoid" [25,44,109,110]. The spectrum of colors ranged from red/purple [12,15,29,53,99,103,106,110] to white/yellow/brown [40,48,53,62,99,101,103] sometimes in a miliary-like or mottled pattern [42,53,[61][62][63]99,101,103].…”

“…Lung lesions consistent with an interstitial pneumonia were described in 77 ICs on Pneumocystis in various mammal species. If stated, the affected animals showed different levels of infection [6,17,25,28,34,35,40,42,44,48,[52][53][54][55][56][57][61][62][63][65][66][67][76][77][78]98,99,[101][102][103][107][108][109][110][111]. In one case of a sable antelope, a moderate focal pneumonia with a low-grade Pneumocystis infection level was mentioned [14].…”

“…• Artiodactyla order: Goat [12,13], sable antelope [14], llama [15], and domestic pig [33]; • Carnivora order: Dog [39,40,42,44,[47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63]66,67], ferret [76], and American mink [77]; • Perissodactyla order: Horse [100-103,107-110]; • Pilosa order: Brown-throated sloth [111].…”