Page 554 - The Veterinary Laboratory and Field Manual 3rd Edition

Important zoonotic diseases 491

in animals), there is also a nasal form in animals ence of cysts. Tapeworm segments can be found
in which schistosome eggs can be found in nasal in human faeces.
secretions.
Control. General hygiene and appropriate latrine
Control: Wash vegetables well in clean water facilities. Do not use human waste as a fertil-
before eating them. Avoid bathing in contami- izer (night manure). Do not contaminate grazing
nated water. pasture with human excrement. Cook all meat
well before consumption. (Dog tapeworm infec-
tions should be controlled by routine worming,
tapeworm see also hydatids.)

Cause: Taenia spp. (Taenia saginata, T. solium).
There are also numerous other tapeworms which toxoplasmosis
may infect humans (including those acquired
from eating raw fish). Taenia species tapeworms Cause: Toxoplasma gondii
also occur in dogs, the cysts of these tapeworms Epidemiology: This protozoan parasite commonly
may occur in sheep, cattle, yaks and pigs (occa- cycles through rodents and domestic and wild
sionally humans) and result in few or no signs, cats. The cat is the end host and frequently shows
however, the cysts of T. multiceps may cause space no outward signs of disease. Rodents, humans
occupying lesions in the brain resulting in ataxia, and other omnivores become infected by consum-
abnormal behaviour and recumbency. ing sporulated oocysts in food contaminated by
Epidemiology: Humans become infected by cat faeces or by consuming infective toxoplasma
ingesting infective cysts in beef (T. saginata) or cysts in meat. Herbivores become infected by
pork (T. solium). Infection with T. solium cysts ingesting oocytes on contaminated pasture.
(Cysticerus cellulosae) may also occur by acciden- Signs in animals: In the adult cat, there may be
tally ingesting the tapeworm eggs in human no signs but in kittens there may be a fever and
faeces. (Humans may also become infected general malaise with myositis and diarrhoea. In
by the cysts of the dog tapeworm T. multi- dogs and humans there may be a non-specific
ceps following the accidental ingestion of dog fever and flu-like signs. In pregnant women, the
faeces.) organism may cross the placenta and cause birth
defects. Abortion may occur in infected sheep.
Signs in animals and humans: There are often
few signs in animals unless the infective cysts Neurological signs may occur in neonates.
develop in the brain or in a medullary cavity of Diagnosis: Serum (preferably paired sera taken
a bone in which the signs will be localized to 2–4 weeks apart) for serology, microscopy, HA,
3
that of the space occupying lesion. In humans FAT and ELISA, faecal samples from cats. Tissue
infected with T. saginata there may be few signs samples from meat animals.
except the passing of tapeworm segments in the
faeces. T. solium infection may result in few signs Control: General hygiene. Pregnant women
in humans unless cysts develop causing hepatic, should not handle contaminated soil or cat fae-
pulmonary or neurological signs. ces. Wash hands after handling meat. Cook all
meat products well before eating.
Diagnosis: Cysts can be seen in meat at the time
of meat inspection. In humans, radiology and
ultrasound may be used to diagnose the pres-

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