(a) Name the causative agent of East Coast fever in cattle. [1] (b) Describe how East Coast fever is transmitted to cattle. [3] (c) A dairy farmer notices t...

(a) The causative agent of East Coast fever is Theileria parva, a protozoan parasite [1].

(b) Transmission of East Coast fever (3 marks):

1. The disease is transmitted by the brown ear tick (Rhipicephalus appendiculatus), which acts as the biological vector [1].
2. When the tick feeds on an infected animal, it ingests blood cells containing Theileria parasites. The parasite undergoes development stages inside the tick [1].
3. When the infected tick subsequently feeds on a healthy animal, it injects the parasite into the animal's bloodstream through its saliva during feeding [1].

(c)(i) Two other signs of East Coast fever besides swollen lymph nodes and fever (any two for [2]):

1. Discharge from the eyes and nose (lacrimation and nasal discharge) [1].
2. Difficulty breathing (dyspnoea) due to fluid accumulation in the lungs [1].

Also acceptable: diarrhoea; loss of appetite; rough coat; anaemia (pale mucous membranes).

(c)(ii) Two preventive measures explained (each for [2], total [4]):

1. Regular acaricide treatment - dip or spray all cattle with an acaricide on a strict schedule (e.g. every 7-14 days during the tick season). This kills ticks on the animals before they can transmit the parasite, breaking the disease cycle. The dip concentration must be maintained correctly to remain effective [2].
2. Quarantine of new stock - isolate newly purchased animals in a separate holding area for at least 21 days before introducing them to the main herd. This observation period allows any incubating disease to become apparent, preventing an infected newcomer from introducing Theileria into a clean herd [2].

Also acceptable: rotational grazing to reduce tick burdens on pasture; vaccination where available (infection-and-treatment immunisation method).