Zoonoses disease-listeriosis, Biology

Listeriosis

Listeriosis is an important food-borne zoonosis caused by pathogenic species of Listeria. The disease affects both in man and animals. It is a serious invasive disease characterized by neural, visceral and reproductive clinical entities and may lead to septicaemia, abortion, stillbirth, meningitis and meningoencephalitis. The disease is also known as leucocytosis, listerial infection, listeriasis, listerellosis, circling disease in animals.


Epidemiology:
Listeriosis occurs throughout the world with varying degree of prevalence. The incidence ranges from sporadic cases to major epidemics. The genus Listeria comprises of 6 species namely L. monocytogenes, L. innocua, L. ivanovii, L. seeligeri and L. welshimeri and L. grayi. Of these, L. monocytogenes and L. ivanovii cause the disease in man and animals. L. monocytogenes is a gram-positive, facultatively anaerobic coccobacillus, motile at 20oC to 25oC and a facultative, intracellular parasite of the reticuloendothelial system. It is widely distributed in animals and man, as well as in the environment and has been isolated from numerous sites, including soil, sewage water and decaying plant material, especially poorly fermented silage.


Clinical features: The symptoms of listeriosis in human are mainly due to septicaemia and encephalomeningitis. Listerial abortion in women usually occurs in the second half of pregnancy and more frequent in the third trimester. The suffering mother may show the symptoms like chills, fever, dizziness and sometimes gastrointestinal disturbances before miscarriage or delivery. Listerial septicemia also occurs among weakened adults, especially patients undergoing long term treatment with corticosteroids or antimetabolites. It may also result in endocarditis, external and internal abscesses and endophthalmitis. A cutaneous eruption has been described among veterinarians who handled infected fetuses of animals. The case fatality is comparatively high that may be as high as 25 to 30 %.


Diagnosis: Diagnosis of listeriosis is made by isolation of the pathogen from blood, cerebrospinal fluid, amniotic fluid or biopsy materials.Conventional serological tests are used for epidemiological surveillance of listeriosis. Outer membrane protein (OMP) of Listeria spp. is also used for developing genus and species specific ELISA. The pathogenicity testing of Listeria isolates by in-vivo methods namely chick embryo and mouse inoculation tests is preferred to confirm the link between isolates and causation of disease. PCR based detection me tho d s ha ve b ee n e mplo ye d a s a d ditio nal to o ls fo r the ide ntific a tio n o f microorganisms. A fragment containing the gene encoding delayed-hypersensitivity- inducing protein is used as a probe to differentiate between pathogenic and non- pathogenic strain of Listeria in clinical, environmental and food samples. PCR- ELISA technique has also been developed to detect and quantify L. monocytogenes in food products.


Prevention and control: Animals with encephalitis and abortion should be separated  and the placenta and fetus should be properly destroyed. New animals should only be added to a herd after undergoing a reasonable period of quarantine.  A common recommendation is to properly ensilage the fodder and avoidance of feeding contaminated, decayed and mouldy silage. Other measures include pasteurization of milk, rodent control and common practices of environmental and personal hygiene. Food from suspected origin should always be adequately cooked. Vegetables that are eaten raw should be washed thoroughly and raw meat should be kept separately from other foods. Veterinarians must take precautions when dealing with parturition, abortions and during autopsies.

Posted Date: 9/20/2012 2:43:37 AM | Location : United States







Related Discussions:- Zoonoses disease-listeriosis, Assignment Help, Ask Question on Zoonoses disease-listeriosis, Get Answer, Expert's Help, Zoonoses disease-listeriosis Discussions

Write discussion on Zoonoses disease-listeriosis
Your posts are moderated
Related Questions
Post removal Technique using PRS kit -Transmetal efficiently doming the post head . -Select suitable sized trephine . -Place drop of RC prep on the post head as lubrican

Explain glycolysis? Name the two monosaccharides which readily enter the glycolytic pathway. Illustrate a diagrammatic sketch of the microscopic view of a mammalian sperm a

Physical Weathering Mechanical forces acting upon the rocks cause physical weathering. Temperature fluctuations cause expansion and contraction of rock surface resulting in the

briefly deccribe the eggs snd follicles

Planning the Nursing Care Monitor fluid intake and urinary output  Administer drugs as advised/prescribed  Monitor the child on dialysis  Provide therapeutic diet

What are the Temporal Factors of Abnormality Given the on going schedule of postnatal neurodevelopment, the age of the child at the time of exposure and the behaviour can have

Explain Submarginal Curved - Limited Mucoperiosteal Flaps - Also called: semilunar flap, - Curved incision in the alveolar mucosa and the attached gingival. - NO advantag

Define Procedure for estimation of vitamin c - colorimetric method? Carry out the experiment following the instructions given herewith: 1. Prepare a series of tubes for blan

Explain process to Control of Breathing? The rate of breathing is controlled by the medulla, the segment of brain stem just above the spinal cord. If the brain stem is cut just

F o wl typhoid Fowl typhoid is caused by Salmonella Gallinarum , a Gram negative bacillus in the family enterobacteriaceae (serogroup D). Chickens are the natural hosts fo