April 2018

Signalment (JPC #2247995):  Young adult female cynomolgus monkey (Macaca fascicularis).     

HISTORY: This monkey was wild-caught in Southeast Asia or the Philippines, and was a control animal on a 14-week study.  She was in apparently good health when euthanized.

HISTOPATHOLOGIC DESCRIPTION:  Lymph node:  Multifocally, within paracortical areas, medullary cords and sinuses are up to 1 mm diameter poorly organized coalescing eosinophilic granulomas composed of a central core of intrahistiocytic and/or extracellular trematode eggs surrounded by concentric layers of numerous multinucleated giant cell macrophages (Langhans and foreign body type) and epithelioid macrophages that are further surrounded by numerous eosinophils, fewer lymphocytes and plasma cells, and occasional layers of hypertrophied fibroblasts.  Eggs are 40 x 50 um, with a yellow-brown, 2-3 um thick refractile shell, prominent lateral spines, and a central 30-40 um-wide, irregular eosinophilic miracidium with numerous 3 um-diameter basophilic nuclei.  Remaining sinuses are diffusely filled with many macrophages, eosinophils, fewer neutrophils, lymphocytes, plasma cells, and are expanded by eosinophilic proteinaceous fluid or clear space (edema).  Lymphoid follicles are diffusely increased in number and size and have prominent germinal centers (secondary follicles) and mantle zones, and there is expansion of paracortical areas (lymphoid hyperplasia), with increased numbers of tingible body macrophages. 

Liver:  Multifocally within portal and periportal areas, replacing hepatocytes and compressing surrounding cords and sinusoids, are coalescing, up to 1 mm eosinophilic granulomas, centered on schistosome eggs as previously described.  Focally, the tunica media of one vessel wall, within a portal area is expanded and effaced by variable numbers of eosinophils, lymphocytes and fibrin which partially occlude the vessel lumen. Diffusely, portal areas are expanded by moderate amounts of fibrous connective tissue and moderate numbers of eosinophils, lymphocytes, plasma cells, and fewer macrophages.  Biliary duct profiles are increased (ductular reaction).  Sinusoids directly surrounding the granulomas contain low to moderate numbers of similar inflammatory cells, with small numbers of brown pigment-laden Kupffer cells. 


  1. Lymph node: Lymphadenitis, granulomatous and eosinophilic, multifocal to coalescing, moderate, with numerous trematode eggs and moderate diffuse lymphoid hyperplasia, Cynomolgus monkey (Macaca fascicularis), nonhuman primate.
  2. Liver: Hepatitis, portal and periportal, granulomatous and eosinophilic, multifocal, with numerous trematode eggs.

ETIOLOGIC DIAGNOSIS:  Lymph node and hepatic schistosomiasis

CAUSE:  Flukes of the family Schistosomatidae

CONDITION: Schistosomiasis, bilharziasis









Eggs in nonhuman primate liver:


Important species that infect domestic animals

Important species that infect nonhuman primates:


  1. Anderson WI, King JM, Uhl EM, Hornbuckle WE, Tennant BC. Pathology of experimental Schistosoma mansoni infection in the eastern woodchuck (Marmota monax). Vet Pathol. 1991;28:245-247.
  2. Brown DL, van Wettere AJ, Cullen JM. Hepatobiliary system and exocrine pancreas. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:447.
  3. Calle PP, Joslin JO. New world and old world monkeys. In: Miller RE, Fowler ME, eds. Fowler’s Zoo and Wild Animal Medicine. Vol 8. St. Louis, MO: Elsevier Saunders; 2015:317.
  4. Corapi WV, Eden KB, Edwards JF, Snowden KF. Heterobilharzia americana infection and congestive heart failure in a llama (Lama glama). Vet Pathol. 2014; Jun 25:Epub 1-4.
  5. Corapi WV, Snowden KF, Rodrigues A, et al. Natural Heterobilharzia americana infection in horses in Texas. Vet Pathol. 2012;49(3):552-556.
  6. Farah IO, Nyindo M, King CL, Hau J. Hepatic granulomatous response to Schistosoma mansoni eggs in BALB/c mice and olive baboons (Papio cynocephalus anubis). J Comp Path. 2000; 1239(1):7-14.
  7. Fradkin JM, Braniecki AM, Craig TM, Ramiro-Ibanez F, Rogers KS, Zoran DL. Elevated parathyroid hormone-related protein and hypercalcemia in two dogs with schistosomiasis. J Am Anim Hosp Assoc. 2001; 37:349-355.
  8. Iburg T, Balemba OB, Dantzer V, Leifsson PS, Johansen MV. Pathogenesis of congenital infection with Schistosoma japonicum in pigs. J Parasitol. 2002; 88(5):1021-1024.
  9. Le Donne V, McGovern DA, Fletcher JM, Grasperge BJ. Cytologic diagnosis of Heterobilharzia americana infection in a liver aspirate from a dog. Vet Pathol. 2016; 53(3):633-636.
  10. Robinson WF, Robinson NA. Cardiovascular system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 3. 6th ed. St. Louis, MO: Elsevier; 2016:91-94.
  11. Ross AGP, Bartley PB, Sleigh AC, Olds GR, Li Y, Williams GM, McManus DP. Schistosomiasis. N Engl J Med. 2002; 346:1212-1220.
  12. Stone RH, Karelma F, Saba CF et al. Lymphosarcoma associated with Heterobilharzia americana infection in a dog. J Vet Diagn Invest. 2011; 23(5):1065-1070.
  13. Strait K, Else JG, Eberhard ML. Parasitic diseases of Nonhuman Primates. In: Nonhuman Primates in Biomedical Research: Diseases. Vol 2. 2nd ed. San Diego, CA: Academic Press; 2012: 250-251.
  14. Van Bolhuis GH, Rijks JM, Dorrestein GM, Rudolfova J, Van Dijk M, Kuiken T. Obliterative endophlebitis in mute swans (Cygnus olor) caused by Trichobilharzia sp. (Digenea: Schistosomatidae) infection.  Vet Pathol. 2004; 41(6):658-665.

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