Listeria info.....

Listeria monocytogenes (Listeria) is a foodborne
illness-causing  bacteria; the illness caused by ingestion of Listeria bacteria
is  called listeriosis. Listeria can invade the body through a normal and 
intact gastrointestinal tract. Once in the body, Listeria can travel  through
the blood stream but the bacteria are often found inside cells. Listeria also
produces toxins that damage cells.

Listeria invades and grows best in the
central nervous system among immune-compromised persons, causing meningitis
and/or encephalitis 
(brain infection). In pregnant women, the fetus can
become infected, leading to spontaneous abortion, stillbirths, or sepsis
(blood infection) in infancy.

Approximately 2,500 cases of listeriosis
are estimated to occur in the U.S. each year. About 200 in every 1000 cases
result in death. 
Certain groups of individuals are at greater risk for
listeriosis, including pregnant women (and their unborn children) and people
with weakened immune systems.

Among infants, listeriosis occurs when the
infection is transmitted from the mother, either through the placenta or during
the birthing 
process. These host factors, along with the amount of
bacteria ingested and the virulence of the strain, determine the risk of 

disease. Human cases of listeriosis are, for the most part, sporadic and
treatable. Nonetheless, Listeria remains an important threat to 
public
health, especially among those most susceptible to this disease.

Listeria
is often isolated in cattle, sheep, and fowl, and is also found in dairy
products, fruits, and vegetables.

Symptoms of Listeria
infection

It is thought that ingestion of as few as 1,000 cells of
Listeria bacteria can result in illness. After ingestion of food
contaminated with Listeria, incubation periods (the time from exposure to onset
of illness) are in the range of one to eight weeks, averaging about 31 

days. Five days to three weeks after ingestion, Listeria has access to all
body areas and may involve the central nervous system, heart, eyes, or other
locations.

A person with listeriosis usually has fever, muscle aches,
and  gastrointestinal symptoms such as nausea or diarrhea. If infection  spreads
to the nervous system, symptoms such as headache, stiff neck, and loss of
balance, confusion, obtundation (decreased consciousness) or convulsions can
occur. With brain involvement, listeriosis may  mimic a stroke. Infected
pregnant women will ordinarily experience only a mild, flu-like illness;
however, infection during pregnancy  can lead to miscarriage, infection of the
newborn, or even stillbirth. Pregnant women are about 20 times more likely than
other healthy adults to get listeriosis; about one-third of listeriosis cases
happen during pregnancy. The incidence of listeriosis in newborns is 8.6 cases
per 100,000 live births. The prenatal and neonatal mortality rate (stillbirths
and early infant deaths) from listeriosis is 80 percent.

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