In a dutch oven or other large pot, heat oil over medium heat.
Add onion, celery, bell pepper and garlic.
Cook for about 5 minutes, or until vegetables are tender.
Add cayenne pepper, thyme, paprika, salt and pepper and stir, cooking for about 1 minute.
Add sausage, rice, tomatoes and their juice and stock. Bring to a boil, then reduce heat to low and allow to simmer, stirring occasionally, until rice is tender and most of the liquid is absorbed, 20-30 minutes.
Stir in the shrimp and cook until shrimp are pink and cooked through, about 5 minutes. Remove from heat, cover and let stand 5-10 minutes. Garnish with parsley.