Habitat Of Alternaria Alternata
- Alternaria species are saprophytic meaning that they thrive in decomposing materials and environments.
- They are also commonly found in organic materials and water or moisture areas.
- Some are endophytic, therefore they live in various plant parts such as seeds, and fruits.
- Alternaria alternata specifically lives in the soil as a saprophyte and decomposition organic matter.
- It is also found on plants where it caused plant diseases and can be transferred to animals through plants causing human and animal infections.
Is There A Risk For A Severe Event
Some people with an Alternaria alternata allergy may also experience symptoms when exposed to other types of mold. This is called cross-reactivity and occurs when your body’s immune system identifies the proteins, or components, in different substances as being structurally similar or biologically related, thus triggering a response.4
Knowing the proteins, or components, within each allergen that are triggering your symptoms can help guide your management plan. With that in mind, and based on your symptom history, your healthcare provider may suggest something called a specific IgE component test, which can help reveal your potential risk profile.4 Results from this test can also help your healthcare provider decide if allergen immunotherapy may reduce your symptoms.16
Already have your specific IgE component test results?
Your component test results will include the name of the components . Your healthcare provider will likely review the results with you, but here you’ll find an at-a-glance breakdown you can use as a reference for the Alt a 1 component:4,16
rAlt a 1
- Your symptoms may be caused specifically by Alternaria.
- Strong association with the presence of allergic rhinitis and asthma, along with asthma severity.
- Allergen immunotherapy may be an option to help stop allergic disease development.
*These products may not be approved for clinical use in your country. Please work with your healthcare provider to understand availability.
Before you proceed …
Pathogenesis In Human Host
- Alternaria alternata has been associated with causing cutaneous and subcutaneous infections, in individuals with an immunocompromised system, therefore it causes opportunistic infections
- Cutaneous infections are localized on the skin, forming skin lesions.
- Subcutaneous infections affect the underlying layers of the skin when the fungi gain entry into the skin causing manifestations on the skin surface.
- The infections may also affect other body parts including the sinus , the nails , and the cornea of the eye causing visual impairment .
- Alternaria alternata also produces mycotoxins which cause mycotoxicosis, but it is rare but not uncommon.
- Mycotoxicosis effects on humans vary from mild to chronic infections but its effect is dependent on the host immunity.
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First Line Of Defense: The Early Response
The human respiratory epithelium is a mucosal surface composed of ciliated cells, mucous-producing cells, and undifferentiated basal cells. It is the first site of contact for all inspired substances, acting as both a physical and an immunological barrier to pathogens and external particles to aid the maintenance of normal airway function . Therefore, when mold spores are inhaled and reach the upper airways, the external epithelial barrier responds by producing antimicrobial molecules, proinflammatory cytokines, and chemokines for immune cell recruitment . Many studies on the effects of fungal extracts in the lungs have focused on how they are recognized by pattern recognition receptors and/or toll-like receptors .
Alternaria, by itself, can induce the activation of the epithelium, inducing a quick release of alarmins such as thymic stromal lymphopoietin , IL-25, and IL-33, and even the production of other inflammatory cytokines such as IL-6 and IL-8 . Likewise, other cellular responses are associated with Alternaria, such as ATP release, calcium signaling, calprotectin production, or eosinophil activation . Interestingly, some of these studies were conducted using heat inactivated Alternaria extracts, which suggests that protease activities are not necessary to induce asthma pathogenesis by this mold.
Growth On Building Materials Or Indoor Environment
Alternaria sp. has been reported worldwide in the indoor environment in air, surface and dust samples . Alternaria is a secondary colonizer and grows on various building materials and indoor substrates. It is often found on floors, in carpets and mattress dust it can establish itself on damp window frames and window putty, walls and ceilings, wallpaper and acrylic paint finishes as well as in humidifier water and ventilation filters it also contaminates textiles , rubber, magnetic tapes, negatives and oil paintings, paper, parchment and certain synthetic materials .
Alternaria is a frequent contaminant in water-damaged or flooded buildings .
In a controlled study on mould growth on wet gypsum wallboard in an indoor environment, Alternaria appeared as a secondary colonizer, being detected more than a month after immersing the building materials in water . In the wake of hurricanes Katrina and Rita in 2005 on the Gulf Coast of Louisiana, thousands of homes were flooded and a characterisation of airborne moulds revealed a high prevalence of Alternaria spp. in both outdoor samples and in indoor air .
On the other hand, a Danish study of 72 mould-contaminated building material samples, collected from 23 public buildings, arrived to a different conclusion: in this study, Alternaria was found to be one of the least frequently encountered fungi .
Alternaria sp. was also detected in one automobile air conditioning system, among 29 sampled cars in Atlanta .
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What Does It Mean If Your Alternaria Alternata Result Is Too High
Exposure to A alternata in US homes is associated with active asthma symptoms.
Alternaria alternata is one of the most common fungi associated with asthma. Not only the presence of asthma but also persistence and severity of asthma have been strongly associated with sensitization and exposure to A alternata. Although exposure to Alternaria is an important risk factor for asthma, few studies have assessed exposure to this fungus in indoor environments.
A alternata, a cosmopolitan saprophyte commonly found in soil and plants, is usually considered an outdoor allergen. Although most intense exposure is likely to occur outdoors, Alternaria and other allergenic fungi are also found in indoor environments. Yet fungal allergen exposures in indoor environments have not been characterized as well as other indoor allergens .
An allergist/immunologist and/or a pulmonologist should be consulted for the diagnosis and long-term follow-up care for any conditions related to mold allergy. An allergist/immunologist can offer advice on how to avoid allergens and may perform skin tests or initiate a course of immunotherapy in people with allergic rhinitis or conjunctivitis if clinically indicated.
How Do I Know If I’m Allergic*
Together with your symptom history, skin-prick testing or specific IgE blood testing can help determine if you are allergic to a particular allergen. If you are diagnosed with an allergy, your healthcare provider will work with you to create a management plan.
*These products may not be approved for clinical use in your country. Please work with your healthcare provider to understand availability.
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Morphological And Cultural Features Of Alternaria Alternata
- In culture, Alternaria alternata grows as long chains with dark brown conidiophores.
- They thrive in environments with moisture and good nutrition, producing asexual spores known as conidiospores .
- The conidia grow on the conidiophores
- The spores are large and appear dark.
- They also have short beaks and fine long septate.
Image Source: The University of Adelaide.
How To Remove Alternaria Mold In Air
The process of removing any species of mold from your homes environment including both the surfaces and the air can be a lengthy procedure that will require the help of specialists that are trained and capable of effectively and safely removing mold from an indoor environment. When it comes to the specific mold species of Alternaria, this type of mold species will produce and release mold spores and allergenic substances into the environment that will latch onto surfaces and hang around in the indoor air for an ambiguous amount of time, depending on the ventilation and air flow within the indoor space. It is important that once you identify mold growth through the mold identification process in your home or begin to experience health effects like allergies in this environment that you quickly work to bring in a mold remediation specialist and air quality solutions to remove the Alternaria mold in your homes surfaces and in the air.
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Blocking Antibodies In Beas
2.5 × 105 BEAS-2B cells were plated in 1 mL DMEM + 1% Pen/Strep/10% FBS. After 24 h, 10 µg/mL of either anti-hTLR2-IgA, 10 µg/mL anti-hTLR4-IgG, 10 µg/mL human IgA2-control, or 10 µg/mL mouse-IgG1-control was added. After 2 h, 100 µg rAlt a 1 was added. Cells were then incubated for 24 h at 37°C/5% CO2. Supernatants were then collected and assayed for cytokines via ELISA as described previously.
Alternaria And Kiwifruit Cosensitization
In addition to Alternaria effects as airborne mold, Alternaria spp. are also well known to infect a wide variety of fruits and vegetables . Alternaria contamination is also documented to trigger food allergy, as reported by Gómez-Casado et al. In controlled infection assays of kiwifruit with Alternaria spores, the authors demonstrated that Alt a 1 was released from spores to kiwifruit pulp, partially inhibiting the activity of a defense plant protein, the PR5 thaumatin-like protein, when hyphal growth was not yet developed. This study found the origin of a co-sensitization phenomenon between Alt a 1 and Act d 2, a major allergen and PR5 of kiwifruit, caused by the consumption of kiwifruits infected with Alternaria but apparently in good conditions . According to the early detection of Alt a 1 in infected kiwifruits, similar results were obtained in citrus fruits, highlighting the value of Alt a 1 as a reliable and specific marker of fungal contamination .
At the same time, the Alternaria-spinach syndrome was also reported in mold-sensitized patients with food allergic reaction after mushroom and spinach ingestions .
Accordingly, food contamination with fungal spores may be the cause of some adverse reactions that patients suffer from, who apparently were not sensitized in the past, and obtained negative results in previous skin prick tests for the diagnosis of a food allergy.
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Biological Effects Of Alternavirus On Their Host
The AaV1 infected strain EGS 35193 , Alternaria alternata showed an abnormal phenotype, including reduced mycelial growth, aerial mycelial collapse, and unregulated pigmentation. In order to investigate whether the high concentration of AaV1 dsRNAs are responsible for this impaired growth, we attempted to eliminate or reduce the dsRNAs from the host fungus strain EGS 35193. By exposing the strain to cycloheximide during hyphal tip isolation, we obtained an isolate E118, in which the amounts of the dsRNAs were reduced. In the isolate E118, the amount of dsRNA was reduced to about one tenth as compared to the parent stain, EGS 35193. The isolate E118 restored normal mycelial growth and pigmentation, suggesting that the high titer of AaV1 caused attenuated mycelial growth of host fungus, strain EGS 35193, Alternaria alternata. After inoculation on PDA agar medium for 24 h, regular-shaped mycelia were observed in the low titer of the isolate E118, but irregular and poor mycelia were observed in the original high titer strain EGS35-193. In addition, abnormally enlarged vesicles appeared in mycelial cells of EGS 35193. Bursting of these enlarged vesicles was observed around the hyphal cells. Only a few small vesicles were observed in cells of the low titer isolate E118. These results indicate that the reduced copy number of the dsRNAs in the restored isolates might be responsible for restoring normal morphology.
S.E. Lopez, D. Cabral, in, 1999
Alternaria And Grass Pollen Cosensitization
Co-sensitization phenomena between Alternaria and other allergens: asthma exacerbation by sensitization to Alternaria grass pollen. In Central Spain, grass pollen patients suffer from asthma during late summer and early fall, when pollen is no longer present. In contrast, in this season, Alternaria spore peaks were registered . Considering that thunderstorms and grass postharvest are common at this time, the authors described the role of spores as Group-1 grass allergen carriers and suggested that the inhalation of loaded spores may be the cause of the asthma exacerbations in grass pollen patients Alternaria, kiwifruit co-sensitization. Alternaria infects kiwifruits secreting Alt a 1 that can be detected in pulp at 5 days post infection while fungal hypha is not visible. The partial inhibition of a PR5 thaumatin-like protein by Alt a 1 was reported, evidencing the role of the fungal protein in plant pathogenesis, and providing an explanation for the co-relation between Alt a 1 and Act d 2 sensitizations as a result of consumption of Alternaria-infected kiwifruits but apparently in good conditions.
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Innate Immunity Induced By The Major Allergen Alt A 1 From The Fungus Alternaria Is Dependent Upon Toll
- 1Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
- 2Department of Pediatrics, School of Medicine, Indiana University Bloomington, Indianapolis, IN, United States
- 3Department of Biology, Randolph College, Lynchburg, VA, United States
- 4Indoor Biotechnologies, Charlottesville, VA, United States
- 5Biocomplexity Institute, Virginia Tech, Blacksburg, VA, United States
- 6Division of Allergic Diseases, Internal Medicine, Mayo Clinic, Rochester, MN, United States
Alt A 1 And Its Flavonol Ligand
Alt a 1 is a small protein mainly detected in mold spores, which is released at the beginning of germination . Although it is included in its own protein family with unknown activity, studies on its homologous Alt b 1 in A. brassicicola and its capacity of inhibiting plant proteins related to pathogenesis suggest a biological role in pathogenicity . Other studies support that Alt a 1-like proteins play a key role in the development of plantfungal interactions .
In addition, Alt a 1 is also well characterized as a major allergen and marker of primary sensitization . It is strongly associated with chronic asthma and is declared as a risk factor for the development and exacerbation of asthma. Its high-resolution X-ray crystal structure reveals a unique -barrel fold formed by eleven chains that are reported to have no equivalent in the Protein Data Bank . The structure is stabilized as a heat-stable, 30 kDa homodimer that dissociates into 15 KDa subunits under reducing conditions or acidic pH. The homodimer shows a butterfly shape stabilized by an intermolecular disulfide bridge between Cys30 from both monomers and by hydrophobic and polar interactions .
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Alt A 1 Induces Innate Immune Responses In Beas
To initially characterize the innate immune response induced by rAlt a 1 in bronchial epithelial cells in vitro, we used human cytokine/chemokine arrays harboring antibodies corresponding to 23 target molecules. Our results indicated that Alt a 1 induced the secretion of several cytokines and chemokines in BEAS-2B human bronchial epithelial airway cellsprimarily MCP-1 , IL-8, and GRO-a/b/g . Similar results were obtained in experiments using NHBE and DHBE cells . There were no marked differences between responses in BEAS-2B, NHBE, and DHBE cells. There was some indication that IL-15 may also be inducible by Alt a 1 in our array studies but was not explored further.
Figure 1. Cytokine profiling of rAlt a 1 treated BEAS-2B cells. 5.0 × 105 BEAS-2B cells were treated with 50 µg rAlt a 1 or 50 µL of endotoxin-free, sterile PBS . Cytokine array blots and corresponding maps of targets derived from cells treated with rAlt a 1, cytokine array blot and corresponding map of targets derived from cells treated with PBS . Comparisons were made between the two blots and cytokines and chemokines highlighted in blue are those that were found to be qualitatively stronger in cells treated with rAlt a 1.
Where Is Alternaria Found
Alternaria is often found in soil and on mediums such as plants, cereal grains, grass, corn silage, rotten wood, bricks, canvas, iron, compost, and bird nests.2,6 Plus, Alternaria is a plant pathogen and can infect more than 4,000 plant species, causing significant damage to grains, fruits, and vegetables, making it responsible for 20 percent of agricultural yield losses.6 In fact, Alternaria molds grow on a host of foods such as tomatoes, cucumbers, cauliflowers, peppers, apples, melons, tangerines, oranges, lemons, and sunflower seeds.13 That said, mold reproduces via spores, which can be transported by air, water, and insects.8,14 So even if a fungus originates outdoors, it often can enter a dwelling through a variety of means, including doorways, windows, vents, and heating and air conditioning systems.15 Therefore, Alternaria alternata can be found indoors on surfaces such as drywall, ceiling tiles, wood, carpet, wallpaper, textiles, window frames, and materials within heating and air conditioning systems.5,6
Prepare for your next visit with your healthcare provider.
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Tomatoes Capsicum And Eggplant
The most important rots of tomatoes and other solanaceous fruit are caused by Alternaria species, most commonly Alternaria alternata, but Alternaria solani may also be responsible. Alternaria rots appear as dark brown to black, slightly sunken, firm-textured lesions. Infection can occur at the stem end of the fruit, or through injury, cracking caused by excessive moisture during growth, or chilling. Geotrichum candidum causes sour rot of tomatoes in cracked or damaged fruit. Cladosporium herbarum, B. cinerea, Rhizopus, and Mucor species can also cause postharvest rots in these fruit, particularly during transport and storage.
Hiren K. Patel, … Bharat Z. Dholakiya, in, 2021
Life Cycle Of Alternaria Alternata
- Dispersion of the conidiospores is by wind or by water, landing in a suitable environment such as plant parts like leaves, fruits, or seed.
- This enables the spore to start germinating when there is enough moisture and temperatures of 31-32°C.
- They develop into long chains that start producing spores from the tips of the hyphae, which is known as a conidiophore.
- The conidiophore is pale or dark brown, appearing as a straight elongated chain or has a flexuous appearance.
- The conidiophore produces brownish conidia with short beaks.
- The conidia that develop have a smooth surface.
Figure: Life Cycle of Alternaria alternata. Image Source: Kuang-Ren Chung.
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