Can parasites cause severe constipation? i went to south africa 4 months ago & while there started to have many symptoms of intestinal parasites.

Unusual: Constipation would be an unusual symptom in intestinal parasite infection. Diarrhea is much more common. But the parasites do affect movement/motility of the bowel, so constipation could be part of the cycle. If you haven't done so already, contact your doctor/health department to submit stool samples to check for all intestinal pathogens. That said, the constipation may well be irritable bowel.