The role of host management in tick population changes on Rusinga Island, Kenya.

Contrary to patterns described elsewhere, tick numbers on Rusinga Island cattle drop markedly after the onset of the rainy season. One possible explanation is that this is related to seasonal differences in host behaviour, since cattle grazing on the island are restricted during the crop-growing season (the rainy season) and free grazing afterwards. In a field experiment, cattle were divided into two groups, free grazing and restricted, for 2 months each during the rainy season and during the dry season, and the number of ticks infesting each group was compared.

Tick (Acari: Ixodidae) infestations on Zebu cattle in western Kenya: seasonal dynamics of four species of ticks on traditionally managed cattle.

A study was conducted on the population dynamics of four tick species infesting livestock on Rusinga Island. Infestations of Rhipicephalus appendiculatus Neumann, Rhipicephalus evertsi evertsi Neumann, Amblyomma variegatum (F.).

Histopathology of attachment sites of Amblyomma variegatum and Rhipicephalus appendiculatus on zebu cattle of varying resistance to ticks.

Mature, unimproved East African Zebu cattle (Bos indicus) naturally exposed to ticks from birth were ranked for resistance to ticks by repeated whole-body counts of infesting ticks. Four cattle of high resistance, four of low resistance and two of intermediate resistance were artificially infested with nymphs of Amblyomma variegatum and Rhipicephalus appendiculatus. Two Friesian cattle (Bos taurus) with less exposure to ticks were similarly infested.

Tick infestations on Zebu cattle in western Kenya: host resistance to Rhipicephalus appendiculatus (Acari: Ixodidae).

Tick-susceptible Friesian steers were used as bait animals to assess the availability of adult Rhipicephalus appendiculatus Neumann on the pasture. Assuming that initial gross pickup rates of ticks by cattle were similar, the numbers of female ticks that attached and the numbers that subsequently fed to maturity on individual cattle were compared based on data obtained from bait animals. The proportion of successful attachments on high-resistance (HR) cattle (0.

Tick infestations on Zebu cattle in western Kenya: quantitative assessment of host resistance.

Groups of previously tick-exposed East African Zebu cattle together with tick-susceptible Friesian steers as controls were artificially infested with adults, nymphs, and larvae of Rhipicephalus appendiculatus Neumann on two occasions. Comparison of the feeding performance data from the two different breeds of cattle showed significant differences in the number and weight of engorged females and the weight of engorged nymphs. Data from the first challenge were used to derive a function for discriminating between resistant and susceptible categories.