Page 553 - The Veterinary Laboratory and Field Manual 3rd Edition

490 Susan C. Cork

Salmonellosis latrine facilities for humans and appropriate facil-
ities for disposing of animal wastes. There are
Cause: Salmonella spp. There are many species of vaccines against some Salmonella spp. infections
Salmonellae that are potentially pathogenic to in poultry and other livestock. Meat and eggs
both livestock and humans. In poultry, the host should be cooked well prior to consumption.
adapted strains are S. pullorum and S. gallinarum.
S. enteriditis occurs in the oviducts of poultry and
may cause food poisoning in humans (via inges- Schistosomiasis
tion of contaminated eggs). In humans, the host Cause: Schistosoma spp.
adapted strain S. typhi is responsible for typhoid
fever. S. typhimurium is a cause of Salmonellosis Schistosoma mansoni causes intestinal schisto-
in many species and is common in rodents. somiasis and is prevalent in Africa and South
America. S. haematobium causes schistosomiasis
Epidemiology: Salmonellae are common in the of the urinary tract and is prevalent in Africa and
intestinal tract of many species, a few are non- the Middle East. S. japonicum occurs in Asia and
pathogenic and cause no disease. In some species, causes intestinal schistosomiasis. Humans are
a host adapted strain may cause no disease but the main hosts for these three species. Other
another strain may result in severe gastro-enter- species may cause cutaneous larva migrans or
itis and often systemic complications. Generally, swimmer’s itch. Other species of schistosomes
salmonellosis is an enteric disease and is con- predominantly infect animals.
tracted through the ingestion of contaminated
feed or water. Rodent contaminated fodder may Epidemiology: This trematode organism is often
infect cattle and pigs as well as humans. Human found in waterways especially slow flowing streams
to human transmission occurs in typhoid espe- and in lakes. Intermediate hosts include snails
cially where hygiene is poor. Systemic disease and other aquatic life. Humans and animals may
with Salmonellae at any time during pregnancy become infected by swimming in contaminated
may result in abortion. Uncooked poultry meat water or by accidentally ingesting schistosomes
and eggs are a special risk to humans. on unwashed vegetation. The organisms live in
the blood vessels of animals, most commonly the
Signs in animals and humans: There may be mesenteric blood vessels but S. haemolyticum lives
no signs or there may be a severe acute gastro- in the blood vessels of the bladder.
enteritis with vomiting (humans) and diarrhoea.
Systemic infections with complications result- Signs in animals: There may be few signs in ani-
ing in death may also occur, these infections are mals but there is sometimes diarrhoea, with or
characterized by fever and possibly a rash. without blood. In humans, the intestinal form of
the disease can be more severe leading to dam-
Diagnosis: Whole blood, serum, faecal smear age of the intestinal tract and wasting. In the
and faeces for culture. In dead animals, fresh and urinary form of the disease there is haematu-
fixed tissues for culture and histological exami- ria and extensive damage to the urinary system
nation. Liver, spleen and heart blood should be unless the disease is treated early.
collected.
Diagnosis: In the human disease (Bilharzia)
Control: Affected animals should be isolated. serum samples, faecal sample, rectal snip, for the
Hygiene is very important, that is, appropriate urinary form, also urine (fixed and fresh). In ani-
food storage to keep rodents out, wash hands mals, faecal samples should be collected (note
after handling animals or using the toilet, good that schistosomes are often not very pathogenic

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