Page 150 - parasitology for medical and clinical laboratoryprofessionals

130 CHAPTER 5

Source: Centers for Disease Control and Prevention (CDC)

FIGURE 5-11 Illustration of the life cycle of the parasitic agents responsible for causing schistosomiasis

of schistosomiasis are primarily due to an allergic type
reaction against the eggs and include splenomegaly
(spleen enlargement), diarrhea, and lymphadenopathy.
In the bladder they produce granulomatous lesions,
hematuria, and sometimes urethral occlusion
(Figure 5-12). Chronic infections with schistosomes
may cause bladder cancers in endemic areas. In the in- Source: Centers for Disease Control and Prevention (CDC)
testine they cause polyp formation and in severe cases
may result in life-threatening dysentery. In the liver the
eggs cause periportal fibrosis and portal hypertension
resulting in hepatomegaly, splenomegaly, and ascites.
A gross enlargement of the esophageal and gastric veins
may result in their rupture. S. japonicum eggs are some- FIGURE 5-12 Histopathology of bladder shows eggs
times carried to the central nervous system and can of Schistosoma haematobium with large numbers of
cause headache, disorientation, amnesia, and even coma. eosinophils