Bacterial Pathogens, Mycotoxins, Viruses, Parasites, and Fish Toxins ◾ 393
was spreading among humans as a result of cannibalism of the brain tissues of infected relatives.
The disease was characterized by degenerative brain with a spongy appearance, and the victims
suffered from rapid physical and mental abnormalities, culminating in paralysis, coma, and death.
The incubation period is about 2–10 years. It became a major concern in the early 1990s when
the disease was detected in cattle, and the wasting of brain tissue resulted in abnormal behavior
in cattle and was thus called mad cow disease. Though there is no human case directly linked to
the consumption of contaminated beef, finding the organism in the late 1990s and early 2000 in
Canada and the United States caused a major beef embargo among developed countries with huge
economic impacts.
Consumption of infected beef products with brain, lymph nodes, or neurons can potentially
cause this disease in humans. It has been documented that cattle likely acquire this from meat and
bone meal (MBM) consisting of sheep offal or beef or dairy cattle. In 1997, the FDA banned the
use of proteins derived from mammalian tissues in feeding to ruminants to prevent transmission.
The infective agent for BSE is not a virus but a protenaceous infectious particle called prion
protein (PrP) that is resistant to most treatments and found primarily in the central nervous system, including brain and neurons. The monomeric form of the protein is 22–36 kDa while the
abnormal or infective molecule is a macromolecular aggregate with molecular mass greater than
400 kDa. The PrP is resistant to protease and accumulates in the neural cells causing vacuolation
(a spongy appearance), cell death, and disrupting brain function.
The psychiatric symptoms include depression, withdrawal, anxiety, paranoid delusions, head
and neck pain, and progressive dementia. The mean duration of suffering is about 14 months. In
the terminal stage, the patient becomes bed bound and also becomes a kinetic mute (a state in
which a person is not able to or will not move or make sounds). There is no diagnostic test available
for testing live animals. Postmortem analyses of brain tissues for spongy appearance and immunoassays (Western blot or ELISA) are used to detect BSE in cattle after slaughter.
Prion is highly resistant to heat and certain chemicals. It can withstand heat treatments of
160°C for 24 hours, 360°C for one hour, and autoclaving at 121°C for one hour. Prion is also
resistant to chemical treatments, such as 0.5% sodium hypochlorite for one hour, 3% hydrogen
peroxide for one hour, and ethanol. However, complete inactivation is possible by autoclaving at
132°C for 1.5 hour, and treatment with 1 M sodium hydroxide at 20°C for one hour or sodium
hypochlorite (2% chloride) for one hour at 20°C. Prevention strategies include (i) stopping feeding
of beef cattle with animal proteins derived from other animals and (ii) identifying and discarding
infected cattle. Currently the European Union and the United States have banned such practices.
Molds and Mycotoxins 13,14
Importance
Infectious molds can cause diseases, such as ringworm, athlete’s foot, etc., and is termed as mycoses. Inhalation of mold spores can lead to allergic diseases in humans. However, many strains of
molds, while growing in a suitable environment (including in foods), produce metabolites that
are toxic to humans, animals, and birds and are grouped as mycotoxins. Consumption of foods
containing mycotoxins causes mycotoxicosis. They are secondary metabolites and not proteins or
enteric toxins. Many are carcinogens and, when consumed, can cause cancer in different tissues
in the body, such as hepatocarcinoma (liver cancer). Some cause toxicity of organs (liver, kidney)
by modulating the cell signaling pathway and programmed cell death. Incidence of mycotoxicosis
was spreading among humans as a result of cannibalism of the brain tissues of infected relatives.
The disease was characterized by degenerative brain with a spongy appearance, and the victims
suffered from rapid physical and mental abnormalities, culminating in paralysis, coma, and death.
The incubation period is about 2–10 years. It became a major concern in the early 1990s when
the disease was detected in cattle, and the wasting of brain tissue resulted in abnormal behavior
in cattle and was thus called mad cow disease. Though there is no human case directly linked to
the consumption of contaminated beef, finding the organism in the late 1990s and early 2000 in
Canada and the United States caused a major beef embargo among developed countries with huge
economic impacts.
Consumption of infected beef products with brain, lymph nodes, or neurons can potentially
cause this disease in humans. It has been documented that cattle likely acquire this from meat and
bone meal (MBM) consisting of sheep offal or beef or dairy cattle. In 1997, the FDA banned the
use of proteins derived from mammalian tissues in feeding to ruminants to prevent transmission.
The infective agent for BSE is not a virus but a protenaceous infectious particle called prion
protein (PrP) that is resistant to most treatments and found primarily in the central nervous system, including brain and neurons. The monomeric form of the protein is 22–36 kDa while the
abnormal or infective molecule is a macromolecular aggregate with molecular mass greater than
400 kDa. The PrP is resistant to protease and accumulates in the neural cells causing vacuolation
(a spongy appearance), cell death, and disrupting brain function.
The psychiatric symptoms include depression, withdrawal, anxiety, paranoid delusions, head
and neck pain, and progressive dementia. The mean duration of suffering is about 14 months. In
the terminal stage, the patient becomes bed bound and also becomes a kinetic mute (a state in
which a person is not able to or will not move or make sounds). There is no diagnostic test available
for testing live animals. Postmortem analyses of brain tissues for spongy appearance and immunoassays (Western blot or ELISA) are used to detect BSE in cattle after slaughter.
Prion is highly resistant to heat and certain chemicals. It can withstand heat treatments of
160°C for 24 hours, 360°C for one hour, and autoclaving at 121°C for one hour. Prion is also
resistant to chemical treatments, such as 0.5% sodium hypochlorite for one hour, 3% hydrogen
peroxide for one hour, and ethanol. However, complete inactivation is possible by autoclaving at
132°C for 1.5 hour, and treatment with 1 M sodium hydroxide at 20°C for one hour or sodium
hypochlorite (2% chloride) for one hour at 20°C. Prevention strategies include (i) stopping feeding
of beef cattle with animal proteins derived from other animals and (ii) identifying and discarding
infected cattle. Currently the European Union and the United States have banned such practices.
Molds and Mycotoxins 13,14
Importance
Infectious molds can cause diseases, such as ringworm, athlete’s foot, etc., and is termed as mycoses. Inhalation of mold spores can lead to allergic diseases in humans. However, many strains of
molds, while growing in a suitable environment (including in foods), produce metabolites that
are toxic to humans, animals, and birds and are grouped as mycotoxins. Consumption of foods
containing mycotoxins causes mycotoxicosis. They are secondary metabolites and not proteins or
enteric toxins. Many are carcinogens and, when consumed, can cause cancer in different tissues
in the body, such as hepatocarcinoma (liver cancer). Some cause toxicity of organs (liver, kidney)
by modulating the cell signaling pathway and programmed cell death. Incidence of mycotoxicosis