Primate Intestinal Nematode Parasitology

Ascaris lumbricoides

• Size: Fertilized 45-85µm, unfertilized 75-110µm

• Color: yellow to brownish, thick shell with albumin coating and mammillations

Trichuris trichiura

• Size: 50-65µm

• Lemon shape with polar plugs

• Thick smooth shell

• Yellowish brown

Capillaria phippinenses

• Size: 35-45um x 20-25µm

• Thick shell with smooth surface

• Color: Light yellowish or brownish

Ancylostoma duodenale / Necator americanus

Ancylostoma duodenale: adults are characterized by a prominent sclerotized buccal capsule armed with teeth and can be transmitted through skin penetration, orally and transplacentally

Necator americanus: is armed with cutting plates and can only be transmitted through skin penetration

Both: eggs are 55-80µm in size and are passed as 2, 4 or multicellular embryo. They are indistinguishable from one another, so they are reported as Hookworm.

Strongyloides

• Clinical significance is same as cat and dog

• Autoinfection is possible

• May spread throughout body tissues in immunosuppressed hosts

• Important to distinguish larvae from those of the Hookworm

• Embryonated eggs may be found occasionally in fresh stool

• Similar to those of the Hookworm but have a thinner shell

Trichostrongylus

• Can infect Primates causing diarrhea and GI upset

• Parasite of herbivores

• Size: 75-120µm

• Similar to the hookworm but usually larger and tapered at one end

• Need to differentiate larvae from those of Strongyloides and Hookworm

Physaloptera

• Stomach worm

• Same morphology and significance as dog and cat

• P. caucasica common in Primates

• Intermediate host is probably orthopteran (cockroaches, crickets, grasshoppers)

Enterobius

• Several species in the Primate • Size: 50-60µm

• Shape: one side flattened, no operculum and thin shelled

• Eggs can be carried through the air

• Probable carrier of Dientamoeba