Entomological study on vectorial density, temporal variation of tsetse fly and other biting flies in intervention and non-intervention areas of South Omo Zone, Ethiopia.

A repeated cross-sectional entomological survey was conducted to estimate Glossina (tsetse) and other biting flies density, their seasonal variation and associated risk factors in intervention and non- intervention areas of South Omo Zone, Southwest Ethiopia from January 2019-November 2019. In both dry and wet seasons, a total of 96 NGU traps (64 traps in tsetse intervention districts and 32 traps in tsetse non- intervention districts) were deployed at an interval of about 100-200 m in purposively selected and suspected tsetse habitats. Thus, Glossina pallidipes was found to be the only cyclical vector along with mechanical vectors of Tabanus, Stomoxys and Haematopota. In tsetse intervention areas, G. pallidipes apparent density of 2.64 F/T/D and 0.42 F/T/D was recorded in dry and wet season respectively. Mechanical vectors (dry; wet) of Tabanus (205; 155), Stomoxys (34; 54) and Haematopota (50; 33) were also recorded in tsetse intervened areas. Whereas, in non- intervention areas, apparent density of G. pallidipes was 2.03 F/T/D and 0.56 F/T/D, respectively in dry and wet season. Similarly, Tabanus (22; 56), Stomoxys (10; 8) and Haematopota (5; 7) respectively in dry and wet (dry; wet) season were recorded in tsetse non- intervention areas. According to Negative Binomial Regression (NBR), season was the only variable significantly affecting (P < 0.05) the Glossina count in the current study area. Accordingly, the incidence G. pallidipes during wet season was decreased by the factor of 0.21 (CI; 0.097-0.47) when compared to its incidence in dry season by holding other variables constant. In conclusion, cyclical vectors were playing vital role in transmission of trypanosomosis in South Omo Zone along with numerous mechanical vectors even though there have been vector intervention activities in the areas. Therefore, strong, sustainable, environmentally friend and community participating vector control strategies should be followed to tackle the vector distribution in the area.

Fatal Africanized bee attack in captive non-human primates (Saimiri ustus and Sapajus libidinosus).

Bee stings (BS) are a life-threatening issue and a growing concern for public health and animals in the Americas. We describe the clinical, pathological, and ultrastructural findings of a massive lethal bee attack in two non-human primates (NHPs). Both animals showed BS scattered throughout the skin, surrounded by a local reaction, diffuse pulmonary congestion, edema, hemorrhage, and remarkable degeneration and necrosis of renal epithelial cells from the proximal and distal tubules, characterizing a systemic bee envenomation reaction.

[Intradermal and serologic testing for insect bite hypersensitivity in a Dahomey-Ox]. / Intradermaler und serologischer Allergietest zur Abklärung einer Insektenstich-Hypersensitivität bei einem Dahomey-Ochsen.

This case report describes an eosinophilic dermatitis on the prepuce of a Dahomey-Ox caused by an insect bite hypersensitivity against Culicoides spp. To the best of the authors' knowledge, this is the first report describing intradermal allergy and serological testing in cattle.

Modified rush venom immunotherapy in dogs with Hymenoptera hypersensitivity.

BACKGROUND: Hymenoptera envenomation occurs frequently in people and dogs and can trigger anaphylaxis. Venom immunotherapy (VIT) is the only preventive treatment for Hymenoptera hypersensitivity and is indicated for people with severe adverse reactions to insect stings. Rush VIT is an accelerated VIT protocol in people. This has not been reported in dogs. OBJECTIVES: The objective of the study was to evaluate the safety of modified rush VIT. ANIMALS: Twenty client-owned dogs with Hymenoptera hypersensitivity based on a history of adverse reactions to Hymenoptera envenomation and a positive intradermal test to honey bee and/or paper wasp venom. MATERIALS AND METHODS: Dogs received incremental doses of venom via subcutaneous injection one day per week for three consecutive weeks until the maintenance dose was achieved. Vital signs were recorded every 30 min prior to venom administration. Adverse reactions were categorised as localised or grade I-IV systemic reactions. RESULTS: Nineteen of 20 dogs (95%) completed rush VIT. One dog experienced a grade III systemic adverse reaction and was withdrawn from the study. No adverse reactions occurred in 10 of 20 dogs (50%). Localised and grade I-II systemic reactions occurred in nine of 20 dogs (45%), including nausea (n = 5), injection site pruritus (n = 3) and diarrhoea and lethargy (n = 1). CONCLUSIONS AND CLINICAL RELEVANCE: Modified rush VIT in dogs was well-tolerated and should be considered for dogs with Hymenoptera hypersensitivity. Larger studies are needed to evaluate the efficacy of VIT in dogs for preventing hypersensitivity reactions to insect stings.

Sensitivity of a Hymenoptera serological immunoglobulin (Ig)E assay for the diagnosis of venom hypersensitivity in dogs.

BACKGROUND: Hymenoptera envenomation with honey bee (Apis mellifera) and paper wasp (Polistes spp.) may cause life-threatening anaphylaxis in dogs. In human patients, clinical history, intradermal testing (IDT) and measurement of allergen-specific serological immunoglobulin (Ig)E (sIgE) are used to support a diagnosis of Hymenoptera venom hypersensitivity. The utility of venom allergen-specific sIgE has not yet been evaluated for this purpose in dogs. OBJECTIVES: The objective of the study was to investigate the sensitivity (sn), specificity (sp) and positive predictive value (PPV) of honey bee and paper wasp serological titres using a commercially available sIgE assay [VARL (Veterinary Allergen Reference Laboratory) Liquid Gold] against clinical history for a diagnosis of Hymenoptera hypersensitivity in dogs. MATERIALS AND METHODS: Honeybee and paper wasp IgE serum titres were measured in 15 client-owned dogs with a diagnosis of Hymenoptera venom hypersensitivity based on a history of anaphylaxis, owner observation of Hymenoptera, and positive IDT to bee and/or wasp; and in 10 client-owned dogs with no known history of anaphylaxis or Hymenoptera exposure and a negative IDT to bee and wasp. RESULTS: Analysis of receiver operating characteristic (ROC) curves demonstrate that a VARL score cut-off of one of six for honeybee yields Sn, Sp and PPV of 40%, 60% and 60%, respectively, and two of six for wasp yields Sn, Sp and PPV of 25%, 78% and 60%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Owing to the poor sensitivity and PPV of sIgE assays for both bee and wasp hypersensitivity in dogs with known envenomation and anaphylaxis, the use of sIgE cannot be recommended as a tool for venom identification.

Equine allergic skin diseases: Clinical consensus guidelines of the World Association for Veterinary Dermatology.

BACKGROUND: Allergic skin diseases are common in horses worldwide. The most common causes are insect bites and environmental allergens. OBJECTIVES: To review the current literature and provide consensus on pathogenesis, diagnosis, treatment and prevention. MATERIALS AND METHODS: The authors reviewed the literature up to November 2022. Results were presented at North America Veterinary Dermatology Forum (2021) and European Veterinary Dermatology Congress (2021). The report was available to member organisations of the World Association for Veterinary Dermatology for feedback. CONCLUSIONS AND CLINICAL RELEVANCE: Insect bite hypersensitivity (IBH) is the best characterised allergic skin disease. An immunoglobulin (Ig)E response against Culicoides salivary antigens is widely documented. Genetics and environmental factors play important roles. Tests with high sensitivity and specificity are lacking, and diagnosis of IBH is based on clinical signs, seasonality and response to insect control. Eosinophils, interleukin (IL)-5 and IL-31 are explored as therapeutic targets. Presently, the most effective treatment is insect avoidance. Existing evidence does not support allergen-specific immunotherapy (ASIT) using commercially available extracts of Culicoides. Hypersensitivity to environmental allergens (atopic dermatitis) is the next most common allergy. A role for IgE is supported by serological investigation, skin test studies and positive response to ASIT. Prospective, controlled, randomised studies are limited, and treatment relies largely on glucocorticoids, antihistamines and ASIT based on retrospective studies. Foods are known triggers for urticaria, yet their role in pruritic dermatitis is unknown. Recurrent urticaria is common in horses, yet our understanding is limited and focussed on IgE and T-helper 2 cell response. Prospective, controlled studies on treatments for urticaria are lacking. Glucocorticoids and antihistamines are primary reported treatments.

Transcription of interleukin 31 and its receptor by leukocytes after Culicoides sp stimulation is dose dependent but is not exaggerated in allergic horses or correlated with pruritus.

OBJECTIVE: Preliminary evidence supports a role for IL-31 in equine insect bite hypersensitivity (IBH) and pruritus. Our studies investigated IL-31 and IL-31 receptor-α (IL-31RA) transcription in leukocytes from normal and IBH horses in response to Culicoides nubeculosus. ANIMALS: 19 normal and 15 IBH horses were recruited in the summer of 2019 (low-dose study) and 8 normal and 10 IBH horses in the winter of 2022 to 2023 (high-dose study). Normal horses had no history or signs of allergic skin disease, while IBH horses had a history and clinical signs compatible with IBH. Pruritus was scored using a visual analog score or a 1 to 6 grading system. PROCEDURES: Whole blood leukocytes were incubated with saline (0.9% NaCl) solution or C nubeculosus (0.26 µg/mL [low dose]; 5 µg/mL [high dose]). Transcription of IL-31 and IL-31RA was measured by quantitative RT-PCR. RESULTS: Transcription of IL-31 and IL-31RA significantly increased in leukocytes from normal and IBH horses following high-dose C nubeculosus, and no differences were found between populations. Following low-dose C nubeculosus IL-31RA, transcription was increased in both normal and IBH horses, but IL-31 transcription was reduced in normal horses. No positive correlation was found between pruritus scores and IL-31 transcription after low- or high-dose C nubeculosus stimulation. CLINICAL RELEVANCE: Exaggerated IL-31 transcription was not identified in IBH horses, suggesting that dysregulation in IL-31 signaling occurs downstream or in localized tissues or involves regulation by yet unidentified receptor splice variants or IL-31-induced increased sensitivity to other pruritogens. Further studies to understand IL-31 signaling in equine allergic skin disease are needed.

Establishment of a protocol for preventive vaccination against equine insect bite hypersensitivity.

Insect bite hypersensitivity (IBH) is a seasonal dermatitis of horses caused by IgE-mediated reactions to bites of Culicoides midges characterized by an imbalance of T-cell subsets. Iceland is free of the causative species but the prevalence of IBH in exported Icelandic horses is especially high. We have shown that intralymphatic (i.l.) vaccination with r-Culicoides allergens in Aluminum hydroxide (alum) and monophosphoryl lipid A (MPLA) adjuvants induces a desired Th1/regulatory T-cell response. The aim of this study was to compare i.l. to subcutaneous (s.c.) injection. Twelve healthy Icelandic horses were injected, i.l. or s.c., three times with four-week interval, using purified r-Culicoides allergens in alum/MPLA. Serum antibody levels and cytokine profile following in vitro re-stimulation of PBMC were analysed. Comparable allergen-specific IgG antibodies were induced following both routes of vaccinations. The antibodies showed similar capacity to block binding of IgE from IBH-affected horse to the allergens. Upon re-stimulation of PBMC, IL-10 was induced. Horses vaccinated i.l. produced more IFN-γ and less IL-4 as compared to the horses injected s.c., but the difference did not reach significance. It can be concluded that applying the simpler s.c. injection instead of i.l. to obtain a suitable immune response could be option in IBH immunotherapy.

Targeting eosinophils by active vaccination against interleukin-5 reduces basophil counts in horses with insect bite hypersensitivity in the 2nd year of vaccination.

Previously, virus-like particle (VLP)-based self-vaccinations targeting interleukin (IL)-5 or IL-31 have been suggested to treat equine insect bite hypersensitivity (IBH), a seasonal recurrent allergic dermatitis in horses. The IL-5-targeting equine vaccine significantly reduced blood eosinophil counts in horses, similar to human monoclonal antibodies targeting IL-5 or the IL-5 receptor alpha (IL-5Rα). Previous studies in humans have also reported an additional effect on reduction of basophil counts. The aim of the present study was to evaluate whether an equine anti-IL-5 vaccine affected blood basophil counts. Horses with IBH were followed in a 3-year trial consisting of a placebo administered in the 1st year, followed by vaccination using an equine (e)IL-5-VLP vaccine in the 2nd and 3rd years. There was a strong reduction in circulating eosinophil counts after vaccination against IL-5. Additionally, there were reduced basophil counts, but only in the 3rd year of the study, suggesting a bystander effect of the anti-IL-5 vaccine on basophil counts.

Oral Calcinosis Circumscripta Associated with Wasp (Hymenoptera vespidae) Sting in a Cat.

In veterinary medicine, calcinosis circumscripta is a morphological diagnosis for which the cause may be known or idiopathic. The aetiology of the lesion must be investigated because the nature of the underlying disease process will dictate appropriate treatment. We present a case of oral calcinosis circumscripta in a cat caused by a wasp sting and associated with moderate unilateral facial oedema. Following corticosteroid therapy and oedema resolution, hyperaemic, circular, firm, elevated lesions were observed on the buccal mucosa and evolved into whitish, slightly elevated multifocal plaques with an irregular surface. As antibiotic and corticosteroid therapy was ineffective, an excisional biopsy was performed after 6 months of lesion development and a diagnosis of calcinosis circumscripta of dystrophic aetiology was made. To our knowledge, this is the first report of calcinosis circumscripta in association with an insect sting in an animal. Insect stings should be included in the differential diagnosis of calcinosis circumscripta in cats.

Onchocerca Cervicalis: A Survey into Awareness and Knowledge of The Parasite Amongst UK Equine Veterinarians.

The nematode Onchocerca cervicalis is the most common causative agent of equine onchocerciasis; this condition is characterised by pruritus and dermatitis and is a differential diagnosis for insect bite hypersensitivity. Onchocerciasis is currently presumed of minor importance within the UK, however prevalence may increase if macrocyclic lactone use declines amid concerns about anthelmintic resistance in gastrointestinal nematodes. This survey aimed to establish O. cervicalis awareness and knowledge levels amongst UK equine veterinarians and to determine approximate numbers of UK horses affected with unresponsive cases of dermatoses, including insect bite hypersensitivity. An online survey was distributed to UK equine vets between December 2019 and February 2020. Of 88 respondents, 78% were aware of O. cervicalis, however 49% of these answered less than half the questions presented about the parasite's lifecycle correctly. Approximately 25% of insect bite hypersensitivity cases respondents saw were deemed unresponsive to standard treatments, 84% of respondents had not previously considered onchocerciasis as a differential diagnosis in such cases. Findings suggest knowledge of O. cervicalis amongst UK equine vets is lacking, highlighting a need to raise awareness and consideration of the parasite as a differential when investigating equine dermatoses.

Adverse events associated with venomous insect immunotherapy and clinical outcomes in 82 dogs (2002-2020).

BACKGROUND: Limited information is known on adverse events and efficacy associated with venomous insect immunotherapy (VIT) in canine patients. OBJECTIVES: To assess adverse events associated with VIT and perceived efficacy of VIT. ANIMALS: Records from 82 client-owned animals which received VIT were assessed. METHODS AND MATERIALS: A retrospective review of records from 2002 to 2020. Clinical history, adverse events during therapy and observations following field stings were collected from all records. Patients were grouped into reactors and nonreactors based on whether or not an adverse event had occurred during therapy. Records were evaluated to determine if a field sting had occurred and the severity of the reaction was compared to pretreatment reaction. RESULTS: Of 82 patients that were identified, 26 experienced a minimum of one adverse event. No deaths or severe anaphylactic reactions were reported. The most common adverse event was gastrointestinal upset. The overall reaction rate per injection was 2.8%. Only variation in sensitisation level (the minimum concentration of venom which elicited a positive intradermal reaction) was significantly different between groups (P = 0.014). Forty-one field challenges in 26 patients were documented. Therapy reduced the severity of reactions in 87.8% of challenges. No deaths were reported. CONCLUSION: Venom immunotherapy appears to be a safe and efficacious treatment for prevention of anaphylaxis due to insect stings in canine patients.

CLINICAL OBSERVATIONS OF BEE ENVENOMATION IN TOUCANS.

There are numerous reports on envenomation, even fatal, secondary to bee attacks in humans and other mammals. In birds, reports on those incidents are scarce and there are none regarding honeybee (Apis mellifera) stings in toucans. In the first case presented, an adult female red-breasted toucan (Ramphastos dicolorus) received at least five bee stings in the periophthalmic area. Within 5 h the bird was lethargic and dehydrated. The urates were yellowish. Three days later the bird showed a moderate anemia, but no changes in the leukocyte count, beyond an elevated heterophil: lymphocyte ratio. Blood chemistry showed hyperglycemia, hypoalbuminemia and elevated aspartate aminotransferase and creatine kinase. Alterations in electrolyte values were also noted. Fourteen days later bile acid elevation was observed. Hematocrit levels normalized after 2 wk. A second incident involved a breeding pair of toco toucans (Ramphastos toco). While the female toco toucan received 10 stings and showed mild clinical manifestations, the male toco toucan was more severely attacked, receiving 40 stings, and died overnight. Despite the relative gravity of the attack (in terms of number of stingers in relation to body weight) both surviving birds recovered in less than 2 wk. To the authors' knowledge, fatal bee envenomation in birds has been reported only in pigeons and macaws. The findings described in this report suggest that toucans are less sensitive to bee venom when compared with pigeons and may have higher tolerance to bee venom compared with mammals. Honeybee envenomation must be considered a potential threat when considering toucan husbandry in zoos and collections.

Venom immunotherapy for Hymenoptera allergy in a dog.

A 1.5-year-old male castrated dog was presented in anaphylactic shock after suffering an apparent bee sting. Immunotherapy with bee venom was initiated based upon history, skin testing and serological testing for allergen-specific immunoglobulin (Ig)E. The dog was maintained on venom immunotherapy for five years and showed no signs of adverse effects from therapy or from repeated bee stings.

Un chien castré de 1,5 ans a été présenté pour choc anaphylactique après avoir été piqué par une abeille. L'immunothérapie avec le venin d'abeille a été initié en fonction des commémoratifs, des tests cutanés et des tests sérologiques pour les immunoglobulines (Ig)E spécifiques d'allergènes. Le chien a été maintenu sous immunothérapie au venin pendant cinq ans et n'a montré aucun effet indésirable du traitement ou a la suite d'autres piqures d'abeilles.

Un perro macho castrado de 1,5 años se presentó en shock anafiláctico luego de sufrir una aparente picadura de abeja. La inmunoterapia con veneno de abeja se inició basándose en el historial, las pruebas cutáneas y las pruebas serológicas para la inmunoglobulina (Ig)E específica de alérgenos. El perro se mantuvo con inmunoterapia con veneno durante cinco años y no experimentó efectos adversos con la terapia o con repetidas picaduras de abeja.

Um cão macho castrado de 1 ano e meio de idade foi apresentado em choque anafilático após aparentemente ter sido picado por abelha. Iniciou-se a imunoterapia com veneno de abelha baseado na história clínica, testes alérgicos cutâneos e sorológicos para imunoglobulina (Ig)E alérgeno-específica. O cão foi mantido em imunoterapia com veneno por cinco anos e não apresentou nenhum efeito adverso do tratamento ou de novas picadas de abelha.

Anaphylaxis-related hemoperitoneum in 11 dogs.

OBJECTIVE: To describe the unique complication of hemoperitoneum associated with anaphylaxis. DESIGN: Retrospective case series from September 2012 to August 2017. SETTING: Two private emergency and specialty referral hospitals. ANIMALS: Eleven client-owned dogs diagnosed with anaphylaxis and hemoperitoneum upon presentation or referral. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Inclusion criteria included clinical signs consistent with anaphylaxis (hypotension, tachycardia, vomiting, diarrhea, weakness, collapse, with or without the presence of dermal signs) due to witnessed or unwitnessed presumed bee sting, an elevated alanine aminotransferase (ALT), performance of abdominal FAST (AFAST) examination with an abdominal fluid score, the sonographic presence of gallbladder wall edema, and hemoperitoneum. All dogs (n=11) were managed medically without surgical intervention. 91% (n=10) of dogs survived to discharge. CONCLUSIONS: Hemoperitoneum development can be seen with anaphylactic reactions, though the exact mechanism remains to be fully understood. Medical therapy is warranted and can be successful in these patients; surgery is not indicated to address hemoperitoneum.

Component-resolved microarray analysis of IgE sensitization profiles to Culicoides recombinant allergens in horses with insect bite hypersensitivity.

BACKGROUND: Allergy to bites of blood-sucking insects, including biting midges, can affect both human and veterinary patients. Horses are often suffering from an IgE-mediated allergic dermatitis caused by bites of midges (Culicoides spp). With the aim to improve allergen immunotherapy (AIT), numerous Culicoides allergens have been produced as recombinant (r-) proteins. This study aimed to test a comprehensive panel of differently expressed Culicoides r-allergens on a cohort of IBH-affected and control horses using an allergen microarray. METHODS: IgE levels to 27 Culicoides r-allergens, including 8 previously unpublished allergens, of which 11 were expressed in more than one expression system, were determined in sera from 347 horses. ROC analyses were carried out, cut-offs selected using a specificity of 95% and seropositivity rates compared between horses affected with insect bite hypersensitivity (IBH) and control horses. The combination of r-allergens giving the best performing test was determined using logistic regression analysis. RESULTS: Seropositivity was significantly higher in IBH horses compared with controls for 25 r-allergens. Nine Culicoides r-allergens were major allergens for IBH with seven of them binding IgE in sera from > 70% of the IBH-affected horses. Combination of these top seven r-allergens could diagnose > 90% of IBH-affected horses with a specificity of > 95%. Correlation between differently expressed r-allergens was usually high (mean = 0.69, range: 0.28-0.91). CONCLUSION: This microarray will be a powerful tool for the development of component-resolved, patient-tailored AIT for IBH and could be useful for the study of allergy to biting midges in humans and other species.

Aedes (Stegomyia) aegypti mosquito bite hypersensitivity in a dog: a case report.

BACKGROUND: Mosquitoes are vectors of several pathogens of considerable importance to humans and companion animals, including nematode helminths such as Dirofilaria immitis and Dirofilaria repens that cause heartworm disease and subcutaneous dirofilariosis, respectively. In addition to mosquito-borne pathogen transmission, mosquito bites can cause discomfort and irritation in pets, and even lead to severe hypersensitivity reactions. In the present study, we report an acute local hypersensitivity reaction in a dog following experimental exposure to Aedes (Stegomyia) aegypti. CASE PRESENTATION: A healthy six-year-old male beagle was included in an efficacy study in which dogs (n = 28) were exposed to Ae. aegypti mosquitoes. On Day - 6, the dog was allocated to one of the study groups, consisting of seven dogs to be treated on Day 0 with an imidacloprid/flumethrin collar. After sedation, animals were exposed to approximately 50 females of Ae. aegypti for 60 (± 5) minutes on Days - 6, 1, 7, 14, 21, 28, 55, and 83. On Day - 6, no allergic reaction to the mosquito bites was observed. However, on Day 1, corresponding to the second challenge, the dog demonstrated an acute allergic reaction characterized by swelling of the face (especially in the base of the muzzle and around the eyes), redness of the eyes, and conjunctival edema of the right eye was also observed. The dog was immediately treated with an intramuscular injection of a commercially available antihistamine treatment, Pen-Hista-Strep® containing a suspension of benzylpenicillin, chlorphenamine, dexamethasone, dihydrostreptomycin, and procaine at a dosage of 1 mL per 10 kg. A few hours after treatment, the dog showed noticeable improvement. CONCLUSIONS: This case provides the first evidence of canine acute local hypersensitivity reaction to mosquito bites under laboratory conditions. This observation suggests that invasive mosquito species such as Aedes spp. may affect the health and comfort of our companion animals, especially for pets with outdoor access without individual protective measures against insect bites.

Essential oil spray reduces clinical signs of insect bite hypersensitivity in horses.

OBJECTIVE: To assess the efficacy of an herbal spray combining various essential oils, with a claim of mast cell stabilisation, antipruritic, anti-inflammatory, and insect repellent effects on the clinical presentation of insect bite hypersensitivity (IBH) in horses. DESIGN: Double-blinded, placebo-controlled, randomised, cross-over clinical trial. METHODS: Twenty adult horses with clinical IBH were treated with a daily application of herbal spray or placebo for 28 days in a randomised, cross-over fashion, separated by a>28-day washout period. Horses were examined and scored prior to and after the completion of each treatment. Histopathology was performed on four horses. Owners kept daily diaries of observations. RESULTS: The herbal spray significantly reduced the severity of all assessed parameters (pruritus, excoriations, lichenification and alopecia; P < 0.05) compared with baseline values (pretreatment) and with placebo. Owners reported improvement of pruritus in 19/20 horses (95%) with complete resolution in 17 horses (85%) following treatment. Skin biopsies showed resolution of orthokeratosis in 4/4 horses, reduced thickness of the stratum spinosum in 2/4 horses and complete resolution of histopathological abnormalities in 1/4 horses after treatment, compared with either no change or deterioration of histopathologic lesions after placebo. No side effects were observed. CONCLUSIONS: The tested herbal spray may be an effective treatment for the management of equine IBH.

Cul o 2 specific IgG3/5 antibodies predicted Culicoides hypersensitivity in a group imported Icelandic horses.

BACKGROUND: Culicoides hypersensitivity (CH) is induced in horses by salivary allergens of Culicoides midges. In Iceland, the causal Culicoides species for CH are not present. Previous epidemiological data indicated that Icelandic horses are more susceptible to CH when they are exported from Iceland and first exposed to Culicoides at adult age. Horses born in countries where Culicoides is endemic, develop the disease less frequently. Here, we established a longitudinal allergy model to identify predictive and diagnostic serological biomarkers of CH. RESULTS: Sixteen adult Icelandic horses from Iceland were imported to the Northeastern United States (US) during the winter and were kept in the same environment with natural Culicoides exposure for the next two years. None of the horses showed clinical allergy during the first summer of Culicoides exposure. In the second summer, 9/16 horses (56%) developed CH. Allergen specific IgE and IgG isotype responses in serum samples were analysed using nine potential Culicoides allergens in a fluorescent bead-based multiplex assay. During the first summer of Culicoides exposure, while all horses were still clinically healthy, Cul o 2 specific IgG3/5 antibodies were higher in horses that developed the allergic disease in the second summer compared to those that did not become allergic (p = 0.043). The difference in Cul o 2 specific IgG3/5 antibodies between the two groups continued to be detectable through fall (p = 0.035) and winter of the first year. During the second summer, clinical signs first appeared and Cul o 3 specific IgG3/5 isotypes were elevated in allergic horses (p = 0.041). Cul o 2 specific IgG5 (p = 0.035), and Cul o 3 specific IgG3/5 (p = 0.043) were increased in late fall of year two when clinical signs started to improve again. CONCLUSIONS: Our results identified IgG5 and IgG3/5 antibodies against Cul o 2 and Cul o 3, respectively, as markers for CH during and shortly after the allergy season in the Northeastern US. In addition, Cul o 2 specific IgG3/5 antibodies may be valuable as a predictive biomarker of CH in horses that have been exposed to Culicoides but did not yet develop clinical signs.

Culicoides spp. found near Lusitano stud farms in mainland Portugal which may contribute for IBH studies.

Insect Bite Hypersensitivity (IBH) is a common cutaneous disease, affecting a large number of horses worldwide. Several studies have identified Culicoides spp. saliva as a clinically relevant allergen source. The prevalence of IBH in Portugal, particularly in Lusitano horses, is still not known. However, the environmental characteristics of the national territory are favorable to the activity of Culicoides, and several species of this genus can be found, namely C. imicola and C. obsoletus/C. scoticus. In this study we characterized the Culicoides population present in Lusitano stud farms with a history of IBH. Thirteen stud farms with Lusitano horses were selected in several regions of mainland Portugal for having a previous history of IBH-affected horses, with a minimum of 5 affected horses. Culicoides were collected in May and June 2016 using OVI traps, placed in these stud farms, and we were able to identify several Culicoides species. We could also verify that C. obsoletus/C. scoticus, and C. imicola were the ones most frequently found, but other species like C. pulicaris were also found.