High density lipoprotein levels in the serum of trypanosensitive and trypanoresistant cattle. Changes during Trypanosoma congolense infection.

Nonpermissiveness to trypanosome infection has been correlated in some instances with the presence of toxic serum factors, e.g. high density lipoproteins (HDL) of human serum can lyse T.b. brucei. The present study examines the possibility of a role for such factors in West African cattle that are resistant to trypanosomiasis. Cattle used in this study were previously selected as resistant or sensitive to trypanosomiasis under heavy natural Glossina challenge. - A comparison of the direct effect of serum from trypanoresistant and trypanosensitive Baoulé cattle on the development of pathogenic bloodstream or metacyclic forms of T. congolense, using modifications of the blood infectivity incubation test, failed to demonstrate a difference between these cattle. High density lipoproteins and cholesterol levels were compared in 115 cattle of known sensibility to trypanosomiasis. HDL-cholesterol formed 91% of the total plasma cholesterol. HDL-cholesterol levels in Zebu (mean of 111.8 mg/100 ml) were significantly higher than those in Baoulé cattle (86.2 mg/100 ml). There was no significant difference, however, in these levels between trypanoresistant (73.4 mg/100 ml) and trypanosensitive (84.5 mg/100 ml) Baoulé. Alterations in HDL-cholesterol levels were monitored during an experimental cyclic infection with T. congolense in 5 Zebu and 9 Baoulé. HDL-cholesterol levels decreased in all animals concomitantly with the appearance of trypanosomes in the blood and returned rapidly to their starting values after parasite elimination following drug treatment.(ABSTRACT TRUNCATED AT 250 WORDS)