JPC SYSTEMIC PATHOLOGY
Signalment (JPC #1622313): Male boa constrictor
HISTORY: This pet snake developed diarrhea that was unresponsive to ampicillin.
HISTOPATHOLOGIC DESCRIPTION: Stomach, glandular portion: Diffusely the gastric mucosa is thickened up to 2mm, forming papillary and frond-like projections (hyperplasia). There are increased numbers of mucous cells that often separate, compress and replace gastric glandular epithelium (mucus hyperplasia and metaplasia). Lining apical and luminal epithelium and free within the lumen are numerous 2-6 um diameter, round, pale amphophilic to basophilic protozoa with variably distinct 1-2 um basophilic nuclei. Multifocally the lamina propria contains small numbers of lymphocytes, plasma cells and fewer heterophils. Diffusely, gastric glands are separated by clear space and multifocally lymphatics are ectatic and contain an eosinophilic, amorphous substance (edema). Occasionally gastric glands are distended by sloughed epithelial cells, cellular debris and few basophilic, 1 X 6 um bacilli.
MORPHOLOGIC DIAGNOSIS: Stomach: Gastritis, proliferative, chronic, diffuse, marked, with mucus neck cell hyperplasia and metaplasia and numerous free and apically attached protozoa, etiology consistent with Cryptosporidium sp., Boa constrictor (Boa constrictor), ophidian.
ETIOLOGIC DIAGNOSIS: Gastric cryptosporidiosis
CAUSE: Cryptosporidium serpentis
Signalment (JPC #3103340): 4-year-old intact male rhesus macaque
HISTORY: Animal was CD8 depleted, treated with anti-IL-15 monoclonal antibody and infected with simian immunodeficiency virus (SIV) to study CD4-T cell kinetics. Months after infection, animal became lethargic and anorexic with weight loss.
HISTOPATHOLOGIC DESCRIPTION: Bile duct, extrahepatic: There is circumferential biliary epithelial hyperplasia, characterized by piling up of epithelial cells with formation of prominent villar-like papillary projections which extend into the lumen. The mucosal epithelium ranges from cuboidal to columnar with large, prominent vesiculate nuclei, increased mitotic figures (up to three per HPF) and scattered apoptotic cells. Goblet cells are increased in number and multifocally replace epithelial cells (goblet cell hyperplasia and metaplasia). Lining the apical and luminal epithelium and free within the lumen are multiple 2-6 um diameter, round, pale amphophilic to basophilic protozoa with variably distinct 1-2 um basophilic nuclei. Multifocally the lamina propria contains moderate numbers of lymphocytes, plasma cells and fewer histiocytes and eosinophils admixed with mild hemorrhage which extends multifocally into the adjacent mesentery. There is mild periductal fibrosis.
MORPHOLOGIC DIAGNOSIS: Bile duct: Cholangitis, proliferative, chronic, circumferential, moderate, with goblet cell hyperplasia and metaplasia, periductal fibrosis and apical protozoa, etiology consistent with Cryptospordium sp., rhesus macaque (Macaca mulatta), nonhuman primate.
ETIOLOGIC DIAGNOSIS: Biliary cryptosporidiosis
CAUSE: Cryptosporidium sp.
- Cryptosporidium sp. are highly infectious, 2-8 um diameter, apicomplexan protozoa that colonize the surface epithelium in the gastrointestinal, biliary and respiratory tracts of mammals, birds, reptiles, and fish
- The protozoa displace the microvilli and are enclosed by surface cell membranes, thus described as intracellular but extracytoplasmic
- Respiratory disease is most significant in birds while enteric disease predominates in other vertebrates
- To date there are 20 recognized Cryptosporidium with nearly 61 genotypes
- Sporulated oocysts are inhaled or ingested; sporozoites are released (excystation) and attach to the apical brush border of enterocytes covering tips and sides of villi, where merogony (asexual), gametogony (sexual), and sporogony occur
- Type I meronts produce up to 8 merozoites, which recycle to form more type I schizonts, or produce type II meronts; type II meronts have 4 merozoites that invade the host cell and undergo gametogony
- Two kinds of oocysts formed: Thin-walled and thick-walled; they sporulate within the host cell
- Autoinfection occurs via thin-walled oocysts; thick-walled oocysts are shed in the nasal secretions and feces
- In snakes, Cryptosporidium causes reduction in acid-secreting granular cells with mucous metaplasia and hyperplasia of mucus neck cells resulting in gastric mucosal hypertrophy
- Cryptosporidium-associated diarrhea develops in mammals primarily due to malabsorption associated with severe villous atrophy, immature enterocytes occupied by high numbers of organisms reducing absorptive surface area, and release of inflammatory mediators, principally prostaglandins that alter mucosal secretion, electrolyte and macromolecule transport
- Primary infection with another agent often causes immunodeficiency thus predisposing animal to secondary infection with Cryptosporidium
- IFN- γ is important for resistance to and clearance of the infection and is a major mediator in host resistance
- In snakes:
- Postprandial regurgitation 1-3 days after eating
- Palpably firm stomach that may cause the surrounding body wall to bulge
- Progressive emaciation without loss of appetite
- In mammals: Diarrhea (subacute or chronic, sometimes bloody, watery)
- Gastric wall often more than a centimeter thick even in small snakes
- Markedly reduced lumen
- Frequently abnormal amount of mucus adherent to the mucosa
- Metaplasia and hyperplasia of mucus neck cells of the gastric glands
- Replacement of the granular cells by mucus cells
- Edema of lamina propria and muscular tunics
- +/- inflammation and necrosis
- Intestinal lesions in mammals: Villus atrophy with blunting and fusion and
hypertrophy and hyperplasia of crypt epithelium
- Numerous organisms attached to brush border of epithelial cells
- One study identified organisms in the epithelium of the common bile duct, the intrahepatic and pancreatic ducts, and the gallbladder of a monkey
- Organism attaches to enterocytes, displacing microvilli
- Enclosed within double layered invagination of host cell membrane on apical surface thus residing intracellularly but extracytoplasmic within a parasitophorous vacuole
- Feeder organelle is present at the base of attachment between the parasitophorous vacuole and cytoplasm of host cell
ADDITIONAL DIAGNOSTIC TESTS:
- Demonstrate organisms after gastric lavage
- Fecal flotation or respiratory fluids in other animals
- Useful stains include modified acid fast stain, Giemsa, merthiolate, Mayer’s hematoxylin
- Fluorescent staining with auramine O or fluorescein-labeled antibody
- Enterocytozoon bieneusi: microsporidian parasite that may infects the intestine, liver or gall bladder of new world monkeys and may easily be mistaken for Cryptosporidium;
- bieneusi has birefringent intracellular spores and is Gram positive
- Cryptosporidium does not stain with gram stain and is located more in the brush border and lumen
- Cryptosporidium with gastric localization:
- andersoni (bovine abomasums, larger usually 6-8 microns)
- muris (gastric gland- mice, gerbils, hamsters, other mammals)
- muris-like organism (gastric glands- cynomolgus monkeys)
- fragile (amphibians)
- serpentis (snakes)
- varanii (reptiles)
- Cryptosporidium with intestinal localization:
- parvum (ruminants, horses, dogs, gerbils, hamsters, mice, and numerous wild animals)
- Suckling calves are the main host of parvum
- In a recent study, infection with C. parvum induced mastocytosis in the mucosa of the entire small intestine in immune competent calves
- hominis (humans, nonhuman primates)
- bovis (calves)
- canis (dogs)
- felis (cats)
- suis (pigs)
- ryanae (bovine is only know host of this species)
- wrairi (guinea pigs – associated with clinical cases of E. coli)
- fayeri, macropodum (marsupials)
- cuniculus (rabbits) – zoonotic significance
- parvum (ruminants, horses, dogs, gerbils, hamsters, mice, and numerous wild animals)
- Birds: baileyi, C. meleagridis, C.galli; C. baileyi most common in chickens , quails, and turkeys, causing intestinal (and cloaca) and respiratory infections; also associated with infectious bursal disease (avian birnavirus); One report of renal and cloacal cryptosporidiosis (C. avian genotype V) in a Major Mitchell's cockatoo (Lophochroa leadbeateri)
- Reptiles: serpentis, C.varanii; C. varanii reported in lizards, snakes and other reptilian species
- Amphibians: fragile; reported in black-spined toads
- Fish: molnari, molnari-like species
- Numerous Cryptosporidium sp. are zoonotic (mainly C. parvum and to a lesser extent C. suis, C. canis, and C. felis); several cases reported in animal handlers caring for infected infant nonhuman primates in a nursery
- Severe fatal infections occur in Arabian foals with CID; humans and monkeys infected with HIV and SIV, respectively; and humans with drug-induced immunosuppression. parvum was responsible for the largest waterborne outbreak of diarrhea in U.S. history
- Case report of 16 green snakes captured in the wild that died or were euthanized for cryptosporidium infections; did not have the classic gastric mucosal hypertrophy but enteritis only as compared to their captive counterparts
- Aural-pharyngeal polyps in Iguana have been associated with cryptosporidium infection
- Barthold SW, Griffey SM, Percy DH. Pathology of Laboratory Rodents and Rabbits. 4th Ames, IA: John Wiley and Sons, Inc; 2016: 82, 108, 152, 189, 204-205, 235-236, 297.
- Brower AI, Cranfield MR. Cryptosproidium-associated enteritis without gastritis in rough green snakes (Opheodrys aestivus) and a common garter snake (Thamnophis sirtalis). J Zoo Wildl Med. 2001;32(1):101-105.
- Curtiss JB, Leone AM, Wellehan JF Jr, Emerson JA, Howerth EW, Farina LL. Renal and cloacal cryptosporidiosis (Cryptosporidium avian genotype V) in a Major Mitchell’s cockatoo (Lophochroa leadbeateri). J Zoo Wild Med. 2015;46(4):934-937.
- Dubey JP, Markovits JE, Killary KA. Cryptosporidium muris-like infection in stomach of cynomolgus monkeys (Macaca fascicularis).Vet Pathol. 2002;39:363-371.
- Gookin JL, Nordone SK, Arenzio RA. Host responses to Cryptosporidium infection. J Vet Intern Med. 2002;16:12-21.
- Li S, Li W, Yang Z, et al. Infection of cattle with Cryptosporidium parvum: Mast cell accumulation in small intestine mucosa. Vet Pathol. 2013;50(5):842-848.
- Mahapatra D, Reinhard M, Naikare HK. Adenovirus and cryptosporidium co-infection in a corn snake (Elaphae guttata guttata). J Zoo Wild Med. 2013;44(1):220-224.
- Masuno K, Yanai T, Hirata A, Yonemaru K, Sakai H, Satoh M, Masegi T, Nakai Y. Morphological and immunohistochemical features of Cryptosporidium andersoni in cattle. Vet Pathol. 2006; 43:202-207.
- McDougald LR: Cryptosporidiosis. In: Swayne DE, ed. Diseases of Poultry. 13th ed. Ames, IA: John Wiley & Sons, Inc; 2013:1167-1171.
- Strait K, Else JG, Eberhard ML. Parasitic Diseases of Nonhuman Primates. In: Abee CR, Mansfield K, Tardif S, Morris T, eds. Nonhuman Primates in Biomedical Research: Diseases, San Diego, CA: Academic Press, Inc; 2012:209-213.
- Uhl EW, Jacobson E, Bartick TE, Micinilio J, Schimdt R. Aural-pharyngeal polyps associated with cryptosporidium infection in three iquanas (Iguana iguana). Vet Pathol. 2001;38:239-242.
- Uzal FA, Plattner BL, Hostetter JM. Alimentary system. In: Maxie MG, ed. Jubb, Kennedy and Palmer’s Pathology of Domestic Animals. Vol 2. 6th ed. St. Louis, MO: Elsevier; 2016:239-241.
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