Known health effects from fungal exposure
include infection, illness from ingestion of mycotoxins, and various
The majority of fungi are not pathogenic to immunocompetent humans. However,
certain fungi are capable of infecting otherwise healthy individuals, including
dermatophytes (Trichophyton, Epidermophyton, and Microsporum), Histoplasma,
Blastomyces, Cryptococcus, Coccidioides, and Paracoccidioides.
In contrast, immunocompromised individuals
are at risk for opportunistic infections with fungi, such as Candida,
Aspergillus, Fusarium, or Mucor. Those most often affected include patients
with advanced acquired human immunodeficiency virus (HIV) syndrome, those on
immunosuppressant therapy or cancer chemotherapy, neutropenic patients, or
patients with poorly controlled diabetes
In the proper setting, fungi can infect
nearly every organ system or can become disseminated and lead to fungal sepsis.
a aspergillosis” and “Fungal
“Candida infections of the bladder,kidneys”.)
mycotoxins — All fungi are capable of producing toxins (mycotoxins), and more
than 300 mycotoxins have been identified . The process and regulation of toxin
production by fungi are poorly understood and appear to depend upon a number of
environmental factors (eg, substrate and moisture levels). In addition,
although a toxin-producing fungus may be present in any
given environment, its presence alone does not ensure that it is producing or
will produce mycotoxins .
Most of the descriptions of mycotoxicosis
in humans are derived from the ingestion of moldy foods . Ingestion of rye and
millet contaminated with the toxin-producing fungus, Claviceps, can lead to
ergotism, which is perhaps the oldest known mycotoxicosis. Ergot is an
alkaloid-containing toxin with vasoconstricting properties. Ergotism can be
subdivided into convulsive (acute) and gangrenous (chronic) forms. The
convulsive form is often accompanied by mania and hallucinations with seizures
and death in severe cases . The gangrenous form, also known as “Saint
Anthony’s Fire,” leads to ischemia and necrosis of the extremities.
Aflatoxins, produced by Aspergillus
species, are also of medical significance. Foods for consumption by humans and
animal feeds are monitored for aflatoxin contamination as part of standard food
safety practices in most developed countries , but contamination of peanut
products supplied to developing nations as nutritional supplements has been
In addition, chronically high dietary
levels of aflatoxins have been implicated in the development of hepatocellular
Other reports of mycotoxicosis in the
literature involve ingestions of fumonisins from Fusarium, ochratoxin from
Penicillium, and trichothecenes from Fusarium, Aspergillus, and Stachybotrys
— Fungi, particularly Aspergillus species, can colonize the paranasal sinuses,
lungs, kidneys, or brain and form noninvasive collections of fungal mycelia (or
fungus balls). These structures generally form in patients with underlying
anatomic abnormalities or previous damage to the affected organ (eg, a
pre-existing pulmonary cavitary lesion) and are treated with surgical removal
aspergillosis” and “Fungal rhinosinusitis
Disorders involving hypersensitivity to
fungi — The term “hypersensitivity” refers to
immunologically-mediated conditions, in which the patient generates an abnormal
immune response to a trigger, resulting in inflammation and symptoms.
IgE-mediated allergy is one type of hypersensitivity reaction. While
“allergic disease” is traditionally associated with an adaptive
IgE-mediated immune response, increasing evidence suggests that the innate
immune system plays an important role, as well .Fungal products can initiate
innate immune responses via their actions on pattern recognition receptors
(PRRs) and through pathogen-associated molecular patterns (PAMPs) or
damage-associated molecular patterns (DAMPs) .
Type 2 innate lymphoid cells (ICL-2s) also
appear to be involved in these processes . Inflammation generated by these
innate responses may account for a lack of correlation between the presence of
IgE antibodies to fungal allergens and the presence of symptoms of allergic
There are several defined disorders that
involve hypersensitivity reactions to fungi, including asthma and allergic
rhinitis, hypersensitivity pneumonitis (HP), allergic bronchopulmonary aspergillosis
(ABPA), and allergic fungal rhinosinusitis (AFRS).
Asthma — The
role of sensitivity to fungal allergens in asthma is relatively
well-established. A growing body of evidence suggests that sensitization and
exposure to outdoor fungi, particularly Alternaria, are associated with asthma .
However, a direct causal relationship between outdoor fungal exposure and
asthmatic symptoms has been more difficult to establish. A pediatric study
revealed that asthma symptoms and need for inhaled bronchodilator therapy were
correlated with the total outdoor spore count . Interestingly, the spore counts
of those fungi to which the children were not skin tested (Basiomycetes and
Ascospores), for which skin testing reagents are not available, correlated
better with symptoms than the counts of those fungi to which the children had
positive skin tests (Deuteromycetes) . Fungal allergy is also associated with
an increased risk of life-threatening and fatal asthma .
Fungal exposure and sensitization appear to
play an important role in lower respiratory tract disease . In addition, a link
between fungi and severe asthma is emerging . The term “severe asthma with
fungal sensitization” (SAFS) has been proposed, and a clinical trial of
the oral antifungal (itraconazole) demonstrated improvement in Asthma Quality
of Life Questionnaire scores in 60 percent of patients . Clearly, further
studies will be needed to establish this treatment for this asthma phenotype
(See “Investigational agents for asthma”, section on ‘Antifungal
Several studies suggest that exposure to
indoor molds and home dampness are related to adverse respiratory health
effects (particularly cough and wheezing), especially in children Often these
studies rely on the self-reported presence of visible mold growth/dampness in
the home. The potential mechanism(s) of these effects are unknown but may not
involve IgE-mediated sensitization.
Findings regarding the relationship between
indoor fungal exposure and asthma are conflicting. Some studies suggest that
fungal exposure is a risk factor for asthma development. These include one that
found that the presence of indoor visible mold growth in the homes of infants
was a risk factor for a positive asthma predictive index (API) at age three
years, another that found an association between airway hyper-reactivity and
exposure to airborne Penicillium species in the home, and a third that found
that mold problems in the kitchen and main living area increased the risk for
wheezing in early childhood . In contrast, other studies failed to find
associations between various measures of indoor mold exposure and later
development of wheezing or asthma in children.
Outdoor fungal exposure may prove to be
more important than indoor exposure. One prospective study found that outdoor
fungal exposure, as opposed to indoor fungal exposure, was associated with
asthma symptoms in inner city asthmatic children , Another study identified
higher exposures to outdoor fungi in the first three months of life as a risk
factor for early wheezing
Allergic rhinitis — It seems intuitive that
IgE-mediated sensitivity to fungal allergens could be a cause of allergic
rhinitis, although literature supporting this assertion is sparse. Allergic
rhinitis symptoms have correlated with positive skin tests and positive in
vitro tests to the common outdoor molds, Alternaria and Cladosporium.
?A meta-analysis of 21 studies on rhinitis
found that self-reported exposure to indoor mold odor conferred an increased
risk for allergic rhinitis , and similarly, the risk for allergic rhinitis was
also increased with self-reported visible indoor mold growth
?Another study found an increased risk of
allergic sensitization with increasing viable indoor mold levels to the
Aspergillus and Cladosporium, and those children exposed to the highest levels
(>90th percentile) of fungi were more likely to experience allergic
?A third study of 6726 children found that
sensitization to Alternaria was associated with allergic rhinitis, independent
Overall, more investigation is needed
regarding the role of fungi and in particular indoor fungi, in the causation of
allergic rhinitis. The evidence to support a role of sensitization to
Stachybotrys chartarum in allergic rhinitis is lacking.
Hypersensitivity pneumonitis — Sensitivity to fungal antigens is among the most common cause of
hypersensitivity pneumonitis (HP) . HP usually develops from occupational
fungal exposures, although there are several reports of HP resulting from
fungal contamination in the home. Fungus-contaminated showers, air conditioning
systems, and humidifiers have been reported as sources of causative antigens in
HP .Species of Epicoccum, Aspergillus, Penicillium, Rhodotorula, and
Aureobasidium, among others, have been implicated”
Allergic fungal rhinosinusitis — Allergic fungal rhinosinusitis (AFRS) patients typically present
with recurrent or chronic rhinosinusitis (CRS) with nasal polyposis, which is
often refractory to prolonged antibiotic therapy. Many have serum
fungal-specific IgE antibodies, as well as elevated serum total IgE levels.
Thick, tenacious mucus, called eosinophilic mucin, is often present in
surgically-obtained specimens. To make the diagnosis, the presence of fungi
must be demonstrated either histologically or with positive fungal cultures.
There must be no evidence of fungal invasion of the underlying mucosa, in order
to differentiate AFRS from invasive fungal sinusitis. Treatment of AFRS
consists of systemic glucocorticoid treatment and surgery to remove allergic
mucin, which is typically impacted and inspissated. Recurrences are common
without ongoing therapy to control inflammation. The diagnosis and management
of AFRS are presented separately.
Chronic rhinosinusitis — It has been
proposed that fungi may be important in the pathogenesis of various forms of
chronic rhinosinusitis (CRS), apart from allergic fungal rhinosinusitis (AFRS),
based on the recovery of fungal organisms from sinus surgical specimens .
However, fungi can frequently be recovered from the nasal passages of normal
individuals. Clear-cut evidence that the presence of fungi (without evidence of
immunoglobulin E IgE-mediated allergy to fungi) causes CRS is lacking, and
treatment with topical antifungals (eg, amphotericin B) has not been
established as an effective therapy
Other research has postulated that the
protease activity of fungi may possibly play a role in the pathogenesis of CRS
through non-IgE-mediated mechanisms. Specifically, protease activity of the
fungus Alternaria has been shown to activate and degranulate human eosinophils,
which are abundant in the mucosa of patients with chronic sinus disease . In
addition, fungal protease may enhance T helper type 2 (Th2)-driven (allergic)
responses by acting as adjuvants that increase IgE-mediated mechanisms in
animal models The role of these
mechanisms in chronic sinus disease remains speculative,
Immunologic disorders — Humans are not known to mount immunologic responses to mycotoxins
as part of any disease process, and tests for antibodies to mycotoxins in human
sera have not been scientifically validated .There is no evidence to support a
role of S. chartarum mycotoxins in the causation of immunodeficiency (also
known as “mold-induced immune dysregulation”) or autoimmunity.
Neurologic symptoms — The role of inhalation of either S. chartarum spores or toxins has
been incriminated as the cause of neurologic symptoms. Most studies
investigating neurologic disorders secondary to fungal exposure have typically
described the complaints in vague terms and did not define specific neurologic
deficits or use objective testing or findings to confirm the presence of
Irritant effects — Several fungal components and metabolites have been studied for
health effects with variable results. Beta-(1,3)-D-glucans are cell wall
components of fungi, plants, and bacteria. Exposure to beta-(1,3)-D-glucans has
been associated with irritant effects on the upper and lower airways in some
studies although this has not been
conclusively proven. Beta-(1,3)-D-glucans can also have immunomodulatory
effects in vitro (eg, dampen Th2 responses) Hydrophobins are surface proteins
produced by filamentous fungi. A hydrophobin from Cladosporium has been
identified as an allergen but the
overall contribution of these allergens to human health has not been
Significant attention has been focused on
volatile organic compounds (VOCs) and their role as respiratory irritants. More
than 300 VOCs have been identified in the typical indoor environment, with the
majority arising from building materials, combustion processes, and consumer
products, such as cleaning and personal care products.
Fungi and other micro-organisms (eg,
bacteria) are also capable of producing VOCs, such as alcohols, ketones, and
aldehydes, which are released into the air , These are collectively called
microbial volatile organic compounds (MVOCs). MVOCs are responsible for the
“musty” odor that often indicates the presence of molds and are also
an indicator of excessive moisture in the environment.
The odor of VOCs may be aversive to some
patients and can cause symptoms in patients with underlying rhinitis or asthma,
although these symptoms generally resolve within a short period of time with
simple avoidance. Exposure to fungal MVOCs has been reported to cause ocular
and upper airway irritation although the overall significance of indoor
environmental fungal VOCs on health has not been clarified.
There is no literature to support the role
of inhalational exposure of Stachybotrys mycotoxins in spontaneous abortions . Similarly,
there is no evidence to implicate S. chartarum mycotoxins in malignancy,
hepatobiliary disease, renal disease, or endocrine disease.
7:. Food an essential component of infection
is an essential component of infection control because it consists of essential
nutrients needed for body development,functions and development of strong immune
system which help to fight against infection, that why we need to eat for healthy
living and not for hunger and this start from food items selection in market and
eaten of a well cooked food.
The following factors contribute to infection
*laziness and bad habitual practices
*peer pressure and
* adequate diet consumption
? Illitracy: In food
selection we need to select food that are
fresh and also the ones that are not destroyed by sunlight, then adequate diet that
contains essetial nutrients for body will help in body immune system development
to fight infection.
If food is cooked for long period of time and
not eaten,the odour need to be perceived to see if the food as not get spoilt or
is still the same taste as at when cooked,because consumption of spoilt food contains
no essential nutrients for body development and strong immune development against
infections any more but infection development in the body, but this is not so in
case of illitrate person that doesn’t have the knowledge about important of adequate
diet to the body whose aims is to eat and also not to waste food.
diet: Food consumed needs to contain all essential nutrients in the right proportion
by selecting varieties of food including vitamins,minerals and water that contain
micro nutrients that are very important in body immune development and functions.
preparation, the environment, utensils, water and food is very important because
hygienic environment prevent breeding of micro organisms that can easily contaminate
food,utensils used to prepare the food need to be well cleansed and the use of coated
pot for example is not good as this coated part is made with chemical that dissolved
into the food gradually and as times goes on it can later leads to chronic infections
later in life.
? Lazziness:consumption of canned and fast food
and Water source used for food preparation is very important as water provide medium
for infection transmission if not portable,food preparation need portable water
for infection control. Laziness will not allow person to prepare food at home even
if the food stuff is available at hand,this makes lazy people to purchase fast food
and canned materials.
low income affect food infection control as this will not allow the person
to purchase diffrerent kinds of food in the market but rather purchase the food
that will satisfy hunger and live more on energy given food like cassava grit and
not adequate diet that help in infection control.
? Miser: This is a person that is extremely
parsimonious and hoards money. Instead of buying food that contains essential nutrients
will rather go for junks like biscuits,buns and cassava grit with sugar because
to him or her food is costly forgetting that all those junks have no nutrients to
meetup the body essential nutrients needed for fighting against infections.
? Peer pressure: influence of what other people
consumed can affect ones diet in food infection control as that person will not
want to be left out among the friends by following them to consume what they consume
either adequate or not. And the fact that my friend do this things I too want to
imitate with out considering the effect as a result of that person desire to belong
to the group affect adequate diet intake ship help in infection control.
the mentioned reasons above affects food
infection control because you are what you eat and what you eat you too as it helps
in control of infection.