Boophilus spp.: Cattle fever tick, tropical cattle tick.

General Description: Inornate ticks with eyes. Palpi and mouth parts are short. Base of capitulum is hexagonal and the scutum is small. Males are small (3 to 4mm long). Fully engorged females are 10 to 12mm in length.

Life Cycle: Boophilus is a one-host tick. Unfed larvae may survive 7 months. Development usually takes place in 1 to 2 months.

Location: Any part of the body of the cattle.

Geographical Distribution: Worldwide.

Significance: Boophilus ticks may transmit babesiosis. Babesia bigemina and B. bovis, the protozoans involved in tick fever, multiply in the ticks and are passed by female ticks to their eggs so the next generation of ticks is automatically infected. Such transovarian transmission increases the spread of cattle tick fever. This disease is characterised by high fever and enlarged spleen and liver with jaundice, emaciation, and death in up to 90 percent of cases. Boophilus spp. ticks also transmit anaplasmosis.

Boophilus microplus (tropical cattle tick) transmits, in addition to the disease mentioned above, Q fever (Rickettsia burnetii) Boophilus calcaratus carries the agents of cattle tick fever and anaplasmosis.

Effect on Host: These ticks cause irritation which leads to licking, biting, and scratching. Secondary bacterial infection may follow. In large numbers the ticks may take sufficient blood to cause anaemia. However, the transmission of disease organisms mentioned above is the most serious aspect of ticks. The first sign of cattle suffering from one of the tick fevers is stiffness when chased. Eventually the infected animal shows lack of coordination of the legs, has a high fever, and eventually falls.

Diagnostic Information: Identification of ticks on cattle.

Control: Tick control by dipping is effective if done on a regular basis. The first chemicals used in tick control were arsenicals. These were followed by chlorinated hydrocarbons. Organophosphorus, carbamate insecticides, synthetic pyrethrins and macrocyclic lacctone such as ivermectin are now used. One-host ticks such as Boophilus are often the first to develop resistance. Therefore control measures have to be changed frequently. A vaccine against Boophilus michrophilus is also available and complements control with ascarids.

Engorged female tick		Scanning electron microscope photo – mouth parts – tick		S.E.M. seed tick