Page 208 - The Veterinary Laboratory and Field Manual 3rd Edition

Parasitology 177

(that is, from adult to egg) transmission. The (that is, jaundiced as a result of intravascular
parasites localize in the salivary gland of the tick haemolysis), the liver is enlarged and brown or
ready for injection into the host animal. yellow in colour, the spleen is enlarged and soft
The risk of infection depends on the distribu- and the lymph nodes are enlarged and haemor-
tion of vector-ticks and in tick-infested areas all rhagic. The kidneys are often pale in colour and
animals become infected. In areas where animal there may be ulceration of the abomasum with
reservoirs of the infection exist, for example, haemorrhages. Diagnosis can be confirmed by
wild bovids, the disease is difficult to eradicate. finding the parasite in stained smears taken from
Imported breeds and immulonogically naïve the lymph nodes or spleen. Ante-mortem diag-
cattle of all ages will be susceptible to the devel- nosis can be confirmed by the examination of a
opment of clinical theileriosis in areas where the stained blood smear (see Figure 5.6) or lymph
disease is endemic. node needle biopsy and by serological testing
(that is, complement fixation and indirect agglu-
cLInIcaL dISEaSE tination, see Chapter 6). Antigen detection and
The clinical findings will depend on: immunofluoresence can also be used to confirm
a diagnosis.
1 the number and species of parasite present
2 the level of general health and immune status controL and PrEvEntIon
of the host. Control is primarily achieved through:

Clinical cases typically have a high tempera- 1 control of the tick vector, for example, treat-
ture, the animal appears depressed and refuses ing animals with acaricide through dipping,
to feed. Anaemia may develop following hae- spraying and dusting (see section 3.8)
molysis of red blood cells and this is followed 2 periodic changing of pasture and burn-
by the development of jaundice (yellow mucous ing abandoned pastures to destroy juvenile
membranes) as the breakdown products of hae- ticks.
moglobin build up in the tissues. The lymph 3 the use of vaccination
nodes may swell and superficial ones can be 4 selection for genetic resistance. E.g. some
palpated (see Figure 8.8). In the later stages indigenous cattle breeds are highly resistant
of a severe infection the animal may develop to ticks.
swelling of the eyelids and ears, nasal discharge
and diarrhoea with mucus and blood leading to The control of cattle movement can also be con-
rapid emaciation followed by death within 8–15 sidered.
days. Mortality may reach 100% in imported and
immunologically naïve animals. Occasionally Babesiosis (Piroplasmosis) =
cerebral infections can occur resulting in nervous red water fever
signs such as circling.
Babesiosis is another tick borne disease of
dIaGnoSIS domestic animals with a worldwide distribution.
Some of the clinical signs associated with Cattle and buffaloes are most often affected but
Theileria sp. may be similar to those seen in clini- sheep, goats, horses, donkeys, dogs and rodents
cal babesiosis and severe cases of anaplasmosis. are also susceptible. There are a number of
Diagnosis can usually be confirmed at necropsy; species in the genus (B. bovis, B. divergens, B.
typically, the carcass is anaemic and yellow bigemina and so on) and some cause only mild or

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