Mosquito allergy: Clinical features and natural course

Mosquito allergy: Immunological aspects and clinical management

Mosquito allergy has been conceived as the cutaneous reactions that appears during and after mosquito biting process; a perception that is supported by several scientific research. Additional data have led to conceive that other manifestations of allergic responses may occur as a cause of the exposure to somatic mosquito allergens. Two main phenotypes of mosquito allergy are identifiable: the cutaneous allergic reactions, induced by salivary allergens, and other manifestations of the allergic responses such as asthma and allergic rhino conjunctivitis that are caused by somatic allergens. The cutaneous reactions have kept the focus of attention of the scientific community. It appears as skin lesions that resembles the phenotype of papular urticaria with a defined natural history of the disease. Although these two phenotypes of mosquito allergy seem to be well differentiated in terms of the allergens that are involved and the routes of exposures, other factors such as geographical distribution, may participate. Mosquitoes have adapted to the host immune response against bites, producing immunomodulatory molecules that counteract such defensive response. The role that the immunomodulatory molecules have on the allergic immune response has not been studied yet and it is still not known if affects all mosquito allergy phenotypes. Only a few studies of allergen specific immunotherapy for cutaneous allergic reactions induced by mosquito bites have been done, and none for respiratory allergic responses. The clinical practice focuses on symptom management and avoiding mosquito bites as much as possible. Avoiding mosquitoes, using different well described methods, is still the best option to limit contact with these insects. The lack of knowledge of mosquito allergy have raised several questions that affects the clinical management of this allergic disease, from its diagnosis, prevention and immunotherapy.

Effectiveness and safety of a cream product containing zinc oxide for alleviating mosquito bite symptoms

BACKGROUND

People frequently experience discomfort with immediate wheal, delayed papules, and pruritus from mosquito bites. A topical cream product containing zinc oxide is commercially available for the management of insect bites, but there has been no published evidence for its effectiveness and safety.

AIMS

To evaluate the effectiveness and safety of this product in symptoms caused by mosquito bites.

METHODS

An open-label, controlled study was performed on 41 healthy participants. All subjects received Aedes aegypti mosquito bites on the forearm. Then test product was randomly applied to the bitten areas of the left or right arm. The other arm was left untreated (control). The onset of pruritus relief was noted. The severity of pruritus was assessed using a visual analogue scale (VAS), ranging from 0 mm (no pruritus) to 100 mm (severe pruritus), and a 4-point pruritus score (0 = none; 1 = mild, not affecting normal activities; 2 = moderate, affecting normal activities to some extent; 3 = severe, significantly affecting activities) at four time points: 15 minutes after the mosquito bite (baseline), as well as 1 hour, 24 hours, and 48 hours after initiating treatment. The size of the bite reaction lesion was also measured at all time points. Any local cutaneous adverse reactions observed during the study were documented.

RESULTS

The onset of pruritus relief in the treated group (25 ± 21.7 minutes) was significantly faster compared to the untreated group (118.7 ± 304.8 minutes). The reduction in VAS score at 1 hour was significantly greater in the product group (30.5 ± 16.22) compared to the control group (14.9 ± 9.9). Moreover, there was a significant difference in the reduction of pruritus score at 1 hour, with the product group (1.1 ± 0.5) showing a higher reduction compared to the control group (0.3 ± 0.4). However, there was no significant difference in the reduction of bite lesion size between the two groups. Throughout the study, no adverse events were reported.

CONCLUSION

Our preliminary findings indicate that the product effectively reduces pruritus caused by mosquito bites but does not have a significant impact on the size of the bite lesions. The product was found to be safe and may be an option for managing mosquito bites pruritus.

Efficacy and Safety of Makabuhay (Tinospora rumphii) 25% Cream Versus Hydrocortisone 1% Cream in the Management of Mosquito Bite Reactions: Randomized Double-Blind Controlled Trial

BACKGROUND

Most insect bite reactions resolve spontaneously, but the inflammation and pruritus induced have been shown to decrease the quality of life. Previous studies have shown the potential anti-inflammatory properties of Tinospora rumphii.

OBJECTIVE

The aim of the study is to assess the efficacy and safety of T rumphii 25% cream versus hydrocortisone 1% cream in the management of local cutaneous reactions caused by mosquito bites.

METHODS

This study was a parallel-group, double-blind, randomized, placebo-controlled trial with a 1-week duration in a span of 3 months (June 2019 to August 2019). Participants were exposed to sterile noninfectious mosquitoes (Aedes aegypti) for 5-10 minutes to elicit cutaneous lesions. Tinospora 25% cream or hydrocortisone 1% cream was applied twice daily throughout the 7-day study period. Of the 70 participants screened for this study, which was approved by an institutional review board (IRB 2019-07) at the Dermatology Outpatient Department of the Research Institute for Tropical Medicine, Alabang, Muntinlupa, Philippines, 58 participants in total met the inclusion criteria and were randomized to treatment (Tinospora: n=29) and active control (hydrocortisone: n=29) groups.

RESULTS

In total, 58 participants were randomized to receive Tinospora cream (n=29) or hydrocortisone cream (n=29). All participants completed the follow-up. There was a significant decrease in lesion size in both groups from the first 15 minutes to day 7 (P<.001). Comparing the lesion size in both groups, there was a statistically significant decrease in lesion size in the first hour (P=.003) and after 24 hours (P=.03). On day 1, 10% (n=29) of participants in the hydrocortisone group and 7% (n=29) in the Tinospora group experienced complete resolution. On day 3, all participants experienced complete resolution. No adverse effects were documented.

CONCLUSIONS

Tinospora 25% cream is safe, effective, and comparable to hydrocortisone 1% cream as an anti-inflammatory agent for mosquito bite reactions based on the decrease in lesion size, the proportion of participants with complete resolution of wheals, and improvement in pruritus intensity score using a visual analog scale. Long-term safety studies are recommended.

TRIAL REGISTRATION

Philippine Health Research Registry PHRR230716-005932; https://www.herdin.ph/index.php/registry?view=research&layout=details&cid=5932.

IgE response to Aed al 13 and Aed al 14 recombinant allergens from Aedes albopictus saliva in humans

Background

Mosquito bite is normally associated with mild allergic responses, but severe localized or systemic reactions are also possible. Reliable tools for the diagnosis of mosquito allergy are still unavailable. Here, we investigated the IgE response to 3 potential salivary allergens identified in the saliva of the tiger mosquito Aedes albopictus.

Methods

Serum from 55 adult individuals (28 controls and 27 allergic people), were analysed using an in-house Enzyme Linked ImmunoSorbent Assay (ELISA) against the Salivary Gland Extract (SGE) and the recombinant proteins albD7l2 (Aed al 2), albAntigen5-3 (Aed al 13) and albLIPS-2 (Aed al 14).

Results

Fifteen of the 27 (56%) individuals having hypersensitive reactions to mosquito bites had IgE serum levels recognizing SGE. Negative sera did not show detectable levels of IgE targeting the SGE from the most common sympatric mosquito Culex pipiens. Among the positive individuals, 2 subjects displayed IgE targeting Aed al 2 (13%), while IgE recognizing Aed al 13 and Aed al 14 were detected in ten (67%) and seven (47%) individuals, respectively. Two sera from non-hypersensitive subjects had detectable levels of IgE targeting Aed al 13, suggesting possible cross-reaction with the homologue salivary proteins of multiple mosquito species or, more generally, of hematophagous insects.

Conclusions

Our results indicate that Aed al 13 and Aed al 14 hold the potential to be developed as tools for the diagnosis of allergy to Ae. albopictus bites. Such tools would facilitate epidemiological studies on tiger mosquito allergy in humans and might foster the development of further protein-based assays to investigate cross-species allergies.

First evaluation of antibody responses to Culex quinquefasciatus salivary antigens as a serological biomarker of human exposure to Culex bites: A pilot study in Côte d'Ivoire

Background

Culex mosquitoes are vectors for a variety of pathogens of public health concern. New indicators of exposure to Culex bites are needed to evaluate the risk of transmission of associated pathogens and to assess the efficacy of vector control strategies. An alternative to entomological indices is the serological measure of antibodies specific to mosquito salivary antigens. This study investigated whether the human IgG response to both the salivary gland extract and the 30 kDa salivary protein of Culex quinquefasciatus may represent a proxy of human exposure to Culex bites.

Methodology/Principal findings

A multidisciplinary survey was conducted with children aged 1 to 14 years living in neighborhoods with varying exposure to Culex quinquefasciatus in the city of Bouaké, Côte d’Ivoire. Children living in sites with high exposure to Cx quinquefasciatus had a significantly higher IgG response to both salivary antigens compared with children living in the control site where only very few Culex were recorded. Moreover, children from any Culex-high exposed sites had significantly higher IgG responses only to the salivary gland extract compared with children from the control village, whereas no difference was noted in the anti-30 kDa IgG response. No significant differences were noted in the specific IgG responses between age and gender. Sites and the use of a bed net were associated with the level of IgG response to the salivary gland extract and to the 30 kDa antigen, respectively.

Conclusions/Significance

These findings suggest that the IgG response to Culex salivary gland extracts is suitable as proxy of exposure; however, the specificity to the Culex genus needs further investigation. The lower antigenicity of the 30 kDa recombinant protein represents a limitation to its use. The high specificity of this protein to the Culex genus makes it an attractive candidate and other specific antibody responses might be more relevant as a biomarker of exposure. These epidemiological observations may form a starting point for additional work on developing serological biomarkers of Culex exposure.

The evaluation of exposure to mosquitoes is a key parameter in assessing the risk of transmission of associated pathogens, including zoonoses. Entomological methods represent the gold standard but have several limitations, and efforts are being made to develop new indicators to accurately assess human–Culex contact. This study showed the IgG response to Culex quinquefasciatus salivary gland extract is suitable proxy of exposure to Culex bites. The lower antigenicity of the 30 kDa recombinant protein represents a limitation to its use. The high specificity of this protein to the Culex genus makes it an attractive candidate and other isotypic antibody responses specific to this salivary antigen might be more relevant as a biomarker of exposure.

Mosquitoes: Important Sources of Allergens in the Tropics

There are more than 3,000 mosquito species. Aedes aegypti, Ae. communis, and C. quinquefasciatus are, among others, three of the most important mosquito allergen sources in the tropics, western, and industrialized countries. Several individuals are sensitized to mosquito allergens, but the epidemiological data indicates that the frequency of sensitization markedly differs depending on the geographical region. Additionally, the geographical localization of mosquito species has been affected by global warming and some mosquito species have invaded areas where they were not previously found, at the same time as other species have been displaced. This phenomenon has repercussions in the pathogenesis and the accuracy of the diagnosis of mosquito allergy. Allergic individuals are sensitized to mosquito allergens from two origins: saliva and body allergens. Exposure to saliva allergens occurs during mosquito bite and induces cutaneous allergic reactions. Experimental and clinical data suggest that body allergens mediate different manifestations of allergic reactions such as asthma and rhinitis. The most studied mosquito species is Ae. aegypti, from which four and five allergens of the saliva and body, respectively, have been reported. Many characterized allergens are homologs to arthropod-derived allergens, which cause strong cross-reactivity at the humoral and cellular level. The generalized use of whole body Ae. communis or C. quinquefasciatus extracts complicates the diagnosis of mosquito allergy because they have low concentration of saliva allergens and may result in poor diagnosis of the affected population when other species are the primary sensitizer. This review article discusses the current knowledge about mosquito allergy, allergens, cross-reactivity, and proposals of component resolved approaches based on mixtures of purified recombinant allergens to replace saliva-based or whole-body extracts, in order to perform an accurate diagnosis of allergy induced by mosquito allergen exposure.

Insect hypersensitivity beyond bee and wasp venom allergy

The bites of blood-feeding insects regularly induce sensitization to salivary proteins and cause local hypersensitivity reactions in over 90% of the population, representing either an IgE-mediated immediate wheal and flare reaction or a T cell-driven delayed papule. Long-lasting large local reactions and bullous reactions may cause significant discomfort and reduction in quality-of-life. Anaphylaxis is rarely reported though proven for several insects, above all mosquitoes, horse flies, and kissing bugs. Recently, salivary gland proteins have been thoroughly studied in some blood-feeding insect species, and several allergens have been identified. Interestingly, many of them belong to the same protein families as the well-known honeybee and wasp venom allergens (phospholipases, hyaluronidases, antigens 5, serine proteases) though sequence identities are mostly low. There is still insufficient evidence for the proposed cross-reactivity between salivary proteins from blood-feeding insects and Hymenoptera venom allergens.

Novel salivary gland allergens from tropical mosquito species and IgE reactivity in allergic patients

Background

Mosquito allergy is common in tropical countries but remains under-diagnosed. This may be due to the lack of knowledge and diagnostic tools for tropical mosquito allergens.

Objective

We aimed to characterize allergens from tropical mosquito species and investigate IgE reactivity in mosquito-allergic patients to the salivary gland proteins from these mosquitoes.

Methods

Salivary gland extract (SGE) from 4 mosquito species, highly distributed in the tropics, including Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles dirus b, were studied. SGE-specific IgE and IgG ELISA were developed, and serum from 64 mosquito-allergic and 22 non-allergic healthy control subjects was assayed. Further investigations using IgE-immunoblots followed by mass spectrometry analysis were performed to identify and characterize allergens from each species.

Results

Mosquito-allergic subjects have detectable serum IgE to SGE derived from local mosquito species, while the IgE levels to Aedes communis using commercially available ELISA were mostly minimal. IgE-immunoblot analysis and mass spectrometry identified 5 novel mosquito allergens from A. albopictus (Aed al 2, Aed al 3), C. quinquefasciatus (Cul q 2.01, Cul q 3), and A. dirus b (Ano d 2). Interestingly, 4 of the 5 new allergens belong to the D7 protein family.

Conclusions & clinical relevance

Five novel allergens from 3 tropical mosquito species were characterized. The majority of mosquito-allergic subjects who live in the tropics have IgE reactivity to these allergens. Our study paves the way for the development of diagnostic tests, component-resolved diagnostics, and future immunotherapy for mosquito allergy in tropical countries.

Evaluation of inflammatory skin infiltrate following Aedes aegypti bites in sensitized and non-sensitized mice reveals saliva-dependent and immune-dependent phenotypes

During probing and blood feeding, haematophagous mosquitoes inoculate a mixture of salivary molecules into their vertebrate hosts' skin. In addition to the anti-haemostatic and immunomodulatory activities, mosquito saliva also triggers acute inflammatory reactions, especially in sensitized hosts. Here, we characterize the oedema and the cellular infiltrate following Aedes aegypti mosquito bites in the skin of sensitized and non-sensitized BALB/c mice by flow cytometry. Ae. aegypti bites induced an increased oedema in the ears of both non-sensitized and salivary gland extract- (SGE-)sensitized mice, peaking at 6 hr and 24 hr after exposure, respectively. The quantification of the total cell number in the ears revealed that the cellular recruitment was more robust in SGE-sensitized mice than in non-sensitized mice, and the histological evaluation confirmed these findings. The immunophenotyping performed by flow cytometry revealed that mosquito bites were able to produce complex changes in cell populations present in the ears of non-sensitized and SGE-sensitized mice. When compared with steady-state ears, the leucocyte populations significantly recruited to the skin after mosquito bites in non-sensitized and sensitized mice were eosinophils, neutrophils, monocytes, inflammatory monocytes, mast cells, B-cells and CD4⁺ T-cells, each one with its specific kinetics. The changes in the absolute number of cells suggested two cell recruitment profiles: (i) a saliva-dependent migration; and (ii) a migration dependent on the immune status of the host. These findings suggest that mosquito bites influence the skin microenvironment by inducing differential cell migration, which is dependent on the degree of host sensitization to salivary molecules.

Cytologic Analysis of Epstein-Barr Virus-Associated T/Natural Killer-Cell Lymphoproliferative Diseases

Rapid, precise diagnosis of Epstein-Barr virus-associated T lymphocyte or natural killer cell lymphoproliferative diseases is clinically important to prevent disease progression and avoid fatal outcomes for patients. In addition to detecting increased copy numbers of Epstein-Barr virus, identification of the lymphocyte subpopulation targeted by the virus infection is crucial to reaching the final diagnosis. However, these procedures are laborious and require large amounts of sample. In contrast, flowcytometric analysis may provide crucial information for initial screening of diseases using only small amounts of sample and involves little labor. In addition to the increase of a particular subpopulation, selective HLA-DR expression indicates selective activation and expansion of a virus-infected clone. Presence of a characteristic HLA-DR^high CD5^dim/negative fraction within CD8⁺ T lymphocytes indicates a possible diagnosis of Epstein-Barr virus-associateds hemophagocytic lymphohistiocytosis. One should note, however, that cases with familial hemophagocytic lymphohistiocytosis may exhibit a similar abnormal fraction within CD8⁺ T lymphocytes. These T cells are oligoclonally expanded reactive T cells expanding in response to B cells infected with Epstein-Barr virus.

Allergenic extracts to diagnose and treat sensitivity to insect venoms and inhaled allergens

OBJECTIVE

To review allergenic extracts used to diagnose or treat insect allergies, including how the extracts are manufactured and their measurements of potency or concentration.

DATA SOURCES

Peer-reviewed articles derived from searching PubMed (National Center for Biotechnology Information) about insect allergies and extract preparation. Encyclopedia of Life (http://www.eol.org/) and http://allergome.org/ were also referenced for background information on insects and associated allergens.

STUDY SELECTIONS

Search terms used for the PubMed searches included insect allergens and allergies, Apidae, Vespidae, fire ants, cockroach allergies, insect allergen extract preparation, and standardization.

RESULTS

Humans may be sensitized to insect allergens by inhalation or through stings. Cockroaches and moths are predominantly responsible for inhalation insect allergy and are a major indoor allergen in urban settings. Bees, fire ants, and wasps are responsible for sting allergy. In the United States, there are multiple insect allergen products commercially available that are regulated by the US Food and Drug Administration. Of those extracts, honeybee venom and insect venom proteins are standardized with measurements of potency. The remaining insect allergen extracts are nonstandardized products that do not have potency measurements.

CONCLUSION

Sensitization to inhalational and stinging insect allergens is reported worldwide. Crude insect allergen extracts are used for diagnosis and specific immunotherapy. A variety of source materials are used by different manufacturers to prepare these extracts, which may result in qualitative differences that are not reflected in measurements of potency or protein concentration.

Allergens involved in the cross-reactivity of Aedes aegypti with other arthropods

BACKGROUND

Cross-reactivity between Aedes aegypti and mites, cockroaches, and shrimp has been previously suggested, but the involved molecular components have not been fully described.

OBJECTIVE

To evaluate the cross-reactivity between A aegypti and other arthropods.

METHODS

Thirty-four serum samples from patients with asthma and/or allergic rhinitis were selected, and specific IgE to A aegypti, Dermatophagoides pteronyssinus, Dermatophagoides farinae, Blomia tropicalis, Periplaneta americana. and Litopenaeus vannamei was measured by enzyme-linked immunosorbent assay. Cross-reactivity was investigated using pooled serum samples from allergic patients, allergenic extracts, and the recombinant tropomyosins (Aed a 10.0201, Der p 10, Blo t 10, Lit v 1, and Per a 7). Four IgE reactive bands were further characterized by matrix-assisted laser desorption/ionization tandem time of flight.

RESULTS

Frequency of positive IgE reactivity was 82.35% to at least one mite species, 64.7% to A aegypti, 29.4% to P americana, and 23.5% to L vannamei. The highest IgE cross-reactivity was seen between A aegypti and D pteronyssinus (96.6%) followed by L vannamei (95.4%), B tropicalis (84.4%), and P americana (75.4%). Recombinant tropomyosins from mites, cockroach, or shrimp inhibited the IgE reactivity to the mosquito at a lower extent than the extracts from these arthropods. Several bands of A aegypti cross-reacted with arthropod extracts, and 4 of them were identified as odorant binding protein, mitochondrial cytochrome C, peptidyl-prolyl cis-trans isomerase, and protein with hypothetical magnesium ion binding function.

CONCLUSION

We identified 4 novel cross-reactive allergens in A aegypti allergenic extract. These molecules could influence the manifestation of allergy to environmental allergens in the tropics.

Identification and Characterization of IgE-Binding Tropomyosins in Aedes aegypti

BACKGROUND

The mosquito Aedes aegypti is a potential source of important clinically relevant allergens. However, the allergenicity and cross-reactivity of most of these has not been fully described.

METHODS

Natural wild-type mosquito tropomyosin was purified by size exclusion and anionic-exchange chromatography from an A. aegypti extract. Further characterization was accomplished by MALDI-TOF/TOF. Two recombinant variants of tropomyosin were obtained by expression in Escherichia coli. Specific IgE measurement by ELISA and skin tests for mosquito extract were performed in 12 patients with asthma or allergy rhinitis residing on the Caribbean island of Martinique. Cross-reactivity between natural A. aegypti tropomyosin and recombinant tropomyosins from A. aegypti, house dust mite, shrimp and Ascaris lumbricoides was analyzed by ELISA competition.

RESULTS

Four variants of natural tropomyosin were purified. A band of 32 kDa in SDS-PAGE representing 2 tropomyosin variants (Aed a 10.0101 and Aed a 10.0201) reacted with specific IgE of 4 of the 12 (33%) allergic patients and with rabbit polyclonal anti-shrimp tropomyosin. A high degree of cross-reactivity (60-70%) was detected between natural mosquito tropomyosin and Blo t 10, Der p 10 and Lit v 1, and a lower degree with Asc l 3 from A. lumbricoides (<30%). rAed a 10.0101 inhibited IgE binding to natural A. aegypti tropomyosin; however, rAed a 10.0201 showed a low inhibitory capacity.

CONCLUSION

Tropomyosin is a new IgE-binding protein from A. aegypti. Two of the 4 variants identified showed different degree of cross-reactivity with tropomyosins from other arthropods. The potential allergenic role of each variant should be further investigated.

Mosquito salivary allergen Aed a 3: cloning, comprehensive molecular analysis, and clinical evaluation

BACKGROUND

Allergic reactions to mosquito bites are an increasing clinical concern. Due to the lack of availability of mosquito salivary allergens, they are underdiagnosed. Here, we reported a newly cloned mosquito Aedes (Ae.) aegypti salivary allergen.

METHODS

A cDNA encoding a 30-kDa Ae. aegypti salivary protein, designated Aed a 3, was isolated from an expression library. The full-length cDNA was cloned into a baculovirus expression vector, and recombinant Aed a 3 (rAed a 3) was expressed, purified, and characterized. Skin prick tests with purified rAed a 3 and Ae. aegypti bite tests were performed in 43 volunteers. Serum rAed a 3-specific IgE levels were measured in 28 volunteers.

RESULTS

The primary nucleotide sequence, deduced amino acid sequence, and IgE-binding sites of Aed a 3 were identified. rAed a 3-selected antibodies recognized a 30-kDa Ae. aegypti saliva protein. rAed a 3 bound IgE in mosquito-allergic volunteers and the binding could be inhibited by the addition of natural mosquito extract dose dependently. Immediate skin test reactions to rAed a 3 correlated significantly with mosquito bite-induced reactions. Of the bite test-positive volunteers, 32% had a positive rAed a 3 skin test and 46% had specific IgE. No bite test-negative volunteers reacted to rAed a 3 in either the skin tests or the IgE assays, confirming the specificity of the assay.

CONCLUSIONS

Aed a 3 that corresponds to the Aegyptin protein is a major mosquito salivary allergen. Its recombinant form has biological activity and is suitable for use in skin tests and specific IgE assays in mosquito-allergic individuals.

Immunological aspects of the immune response induced by mosquito allergens

Allergies caused by mosquito bites may produce local or systemic reactions. The inhalation of mosquito allergens may also cause asthma and/or allergic rhinoconjunctivitis in sensitized individuals. The mechanisms implicated in the development of these immune responses involve IgE antibodies, different subtypes of IgG and proinflammatory cytokines as well as basophils, eosinophils and mast cells. Several allergenic components have been identified in the saliva and bodies of mosquitoes and some of these are present in different mosquito species. The most common species implicated in allergic reactions belong to the genera Aedes, Culex and Anopheles. Several Aedes aegypti allergens have been cloned and sequenced. The recombinant molecules show IgE reactivity similar to that of the native allergens, making them good candidates for the diagnosis of mosquito allergies. Allergen-specific immunotherapy with mosquito extracts induces a protective response characterized by a decreased production of IgE antibodies, increased IgG levels, a reduction in the severity of cutaneous and respiratory symptoms and the need for medication. The aims of this review are to summarize the progress made in the characterization of mosquito allergens and discuss the types of immune responses induced by mosquito bites and the inhalation of mosquito allergens in atopic individuals.

Flood-related skin diseases: a literature review

Flood is one of the most common natural disasters, which commonly occurs in all parts of the world. The effects of the disasters considerably become enormous problems to overall public health systems. Flood-related skin diseases are a portion of these consequences presenting with cutaneous manifestations and/or signs of systemic illnesses. We conducted a systematic literature review of research publications relating to flooding and skin diseases. The purpose of this review was to provide dermatologists as well as general practitioners with comprehensive conditions of flood-related skin diseases and suggested treatments. Moreover, we categorized these flood-related diseases into four groups comprising inflammatory skin diseases, skin infections, traumatic skin diseases, and other miscellaneous skin diseases in a bid to implement early interventions and educate, prevent, and efficaciously handle those skin diseases under such a catastrophic situation so that better treatment outcomes and prevention of further complications could be ultimately achieved and accomplished.

Anaphylaxis in an emergency setting - elicitors, therapy and incidence of severe allergic reactions

BACKGROUND

Anaphylaxis is a severe potentially life-threatening hypersensitivity reaction with an estimated lifetime prevalence of 0.5-2.0%. The prevalence and incidence of anaphylactic reactions in Germany are unknown. We therefore assessed anaphylactic patients seen by emergency physicians in the Berlin area covering 4 million people.

METHODS

A standardised questionnaire was filled from 2008 to 2010 by the emergency physicians.

RESULTS

A total of 333 cases of anaphylaxis were reported. 295 of these met the inclusion criteria for severity and were analysed. 13.9% (n = 41) were reactions with respiratory symptoms, 25.4% (n = 75) with cardiovascular, and in 60.7% (n = 179) of cases, respiratory and cardiovascular symptoms were reported. Two reactions were fatal. The most common elicitors were food products (32.2%), drugs (29.2%) and insect venom (19.3%). The most frequently given drugs were corticoids and antihistamines, but not adrenaline. For 2008, the calculated incidence was 4.5 per 100 000.

CONCLUSIONS

Our data show that food products are frequent elicitors of severe allergic reactions in the general population including children and adults. It unravels a strong underuse of adrenaline by emergency physicians, not reflecting treatment protocols according to the current guidelines. As data obtained from allergists reveal a different rank order of elicitors, this study suggests that food-allergic adult patients may present a risk population and should receive more attention by allergists.

Delayed-type hypersensitivity to sand fly saliva in humans from a leishmaniasis-endemic area of Mali is Th1-mediated and persists to midlife

Immunity to sand fly saliva in rodents induces a T_H1 delayed-type hypersensitivity (DTH) response conferring protection against leishmaniasis. The relevance of DTH to sand fly bites in humans living in a leishmaniasis-endemic area remains unknown. Here, we describe the duration and nature of DTH to sand fly saliva in humans from an endemic area of Mali. DTH was assessed at 24, 48, 72, and 96 hours post bite in volunteers exposed to colony-bred sand flies. Dermal biopsies were obtained 48 hours post bite; cytokines were quantified from peripheral blood mononuclear cells (PBMCs) stimulated with sand fly saliva in vitro. A DTH response to bites was observed in 75% of individuals aged 1–15 years, decreasing gradually to 48% by age 45, and dropping to 21% thereafter. Dermal biopsies were dominated by T lymphocytes and macrophages. Abundant expression of IFN-γ and absence of T_H2 cytokines establishes the T_H1 nature of this DTH response. PBMCs from 98% of individuals responded to sand fly saliva. Of these, 23% were polarized to a T_H1 and 25% to a T_H2 response. We demonstrate the durability and T_H1 nature of DTH to sand fly bites in humans living in a cutaneous leishmaniasis-endemic area. A systemic T_H2 response may explain why some individuals remain susceptible to disease.