EFFECTS OF HEMAGGLUTINATION (LECTIN) INHIBITORY SUGARS ON THEILERIA-PARVA INFECTION IN RHIPICEPHALUS-APPENDICULATUS

We have previously described the presence of haemagglutinins in tissue s of the tick, Rhipicephalus appendiculatus and determined their sugar specificities by inhibition experiments. In this study, haemagglutina tion inhibitory sugars are shown to have an effect in vivo on the abun dance of Theileria parva infected salivary gland acini in Rhipicephalu s appendiculatus. A significant increase (P <0.05) was observed in T. parva acinar infection rates in the salivary glands of R. appendiculat us fed on ears of rabbits infused with melibiose and raffinose. In con trast, mannose and turanose (non-haemagglutination inhibitory sugars) did not cause elevation of T. parva acinar infection rates. The effect of melibiose in elevating acinar infections was observed when used on ly during T. parva maturation in the salivary glands but not during pa rasite pick-up from an infected bovine host. Stabilates produced from ticks with elevated acinar infections did not differ from control stab ilates in infectivity to cattle, by comparison of prepatent periods to pyrexia, or parasitosis, or in the severity of reactions.