Quantitative studies on Theileria parva in the salivary glands of Rhipicephalus appendiculatus adults: Quantitation and prediction of infection

Abstract Quantitative studies on Theileria parva in the salivary glands of Rhipicephalus appendiculatus adults: Quantitation and prediction of infection. International Journal for Parasitology 16 : 93–100. A simplified and robust Feulgen's reaction was found superior to the periodic acid-Schiff reaction and a modified methylgreen-pyronin stain for quantitating Theileria parva infections in salivary glands of adult Rhipicephalus appendiculatus and also for assessing their stage of development. In the latter case Feulgen's reaction was comparable to Giemsa stained impression smears. Prevalence (number of infected ticks/number of ticks examined), mean intensity (number of infected acini/infected tick) and abundance (number of infected acini/tick examined) were calculated. The former two descriptors of infection were positively correlated. The distribution of the values of intensity of infection was strongly skewed to the left. As with reasonable numbers a coefficient of variation of about 0.1 could not be reached, the minimum sample size was set at 60 females and 30 males, the minimum contents of one tick tube. There was only little coincidence between the infection in a hemolymph-gut smear and the salivary glands of the same tick. Both salivary glands were equally susceptible to T. parva infection.