Sensitisation To Imbrasia Belina (Mopane Worm) and Other Local Allergens in Rural Gwanda District of Zimbabwe

Background The prevalence of allergic diseases is increasing in Zimbabwe and the data relate to local as well as exotic allergen sources. As entomophagy, the practice of eating insects, is a recognised source of local allergens, we sought to measure the prevalence of and risk factors for sensitisation to Imbrasia belina (mopane worm), a popular edible insect. This was investigated alongside other locally relevant allergens in a rural community in Gwanda district, south of Zimbabwe. Methods A cross sectional study was conducted among 496 adults and children aged 10 years and above in Gwanda district, a mopane worm harvesting area in Zimbabwe. Data on individual characteristics, mopane worm exposure factors, sensitivity to commercial allergen extracts (Stallergenes, France) and in-house extracts of mopane worm (Imbrasia belina) and mopane leaves (Colophospermum mopane) were collected at a local clinic. Data were analysed using Stata version 13 software. Results The prevalence of sensitisation to at least one allergen was 31.17% (n = 144). The prevalence of atopy was higher in adults (33.33%) than in children (23.53%) (p = 0.059). The commonest inhalant allergen sources were mopane worm (14.29%), Tyrophagus putrescentiae (14.29%), mopane leaves (13.42%), Alternaria alternata (6.49%) and Dermatophagoides pteronyssinus (6.49%). Polysensitisation was demonstrated in the study population and of the 108 participants who were sensitised to two or more allergens, 66 (61%) were women. Sensitisation to mopane worm and mopane leaves often clustered with Tyrophagus putrescentiae amongst adults. Adjusted logistic regression analyses between mopane worm sensitisation and self-reported exposure variables showed that sensitisation was more likely amongst mopane worm harvesters (OR = 1.92, 95%CI = 0.77–4.79), those who cooked or roasted mopane worms during harvesting (OR = 2.69, 95%CI = 0.78–9.31) and harvesting without personal protective equipment (PPE) (OR = 2.12, 95%CI = 0.83–5.44) compared to non-harvesters. Conclusion Atopic sensitization was common in this mopane worm harvesting community in Gwanda district of Zimbabwe. There was frequent co-sensitisation of mopane worm and mopane leaves with Tyrophagus putrescentiae in children and adults. It is important to determine the clinical relevance of our findings, particularly relating to mopane worm sensitisation.

A feasibility study to assess Imbrasia belina (mopane worm) sensitisation and related respiratory health outcomes in a rural community in Gwanda district, Zimbabwe

Background Allergic diseases are considered to be some of the fastest growing chronic conditions in Africa. Of concern is the paucity of knowledge about the local environment and its role in allergic disease development. In response to this, we explored whether Imbrasia belina, a popular indigenous edible insect commonly known as mopane worm, is a potential allergen of clinical and public health significance in Zimbabwe. This study was intended to assess the plausibility and feasibility of this hypothesis with a view to evaluate the insect’s health impact in a larger study. Methods The study participants included male and female villagers aged 10 years and above in Gwanda district, Zimbabwe. Eligible participants who completed the household questionnaire were referred to the local clinic for skin prick tests and to measure lung function and allergic airway inflammation. Allergen sensitisation patterns were evaluated using 10 different inhalant allergen extracts including an in-house preparation of mopane worm. Lung function was measured with a Koko Legend spirometer, and fractional exhaled nitric oxide levels (FeNO) (NIOX VERO) were measured in participants with at least one abnormal spirometric parameter. Data was analysed using Stata version 13 software. Results Of the 46 eligible participants that completed the household questionnaire, 17 went to the clinic giving a response rate of 37%. The majority who completed the questionnaire were adults (91%) and the children (9%) were all female. The prevalence of sensitisation to Imbrasia belina was 50%, and the prevalence ranged from 22 to 72% for the other allergens including cockroach, mosquito and house dust mites. The data collection tools were safe and well tolerated by participants with no adverse events reported. Self-reported respiratory symptoms, abnormal lung function and elevated FeNO were recorded amongst participants sensitised to mopane worm. Conclusion Pre-defined feasibility criteria were met with the exception of a lower than expected response rate for clinic data collection in this pilot study. For the main study, modifying the sampling strategy and applying more consistent community engagement will improve the response rates.

A Feasibility Study to Assess Imbrasia Belina (Mopane Worm) Sensitisation and Related Respiratory Health Outcomes in a Rural Community in Gwanda District, Zimbabwe

Background: Allergic diseases are considered to be some of the fastest growing chronic conditions in Africa. Of concern is the paucity of knowledge about the local environment and its role in allergic disease development. In response to this, we explored whether Imbrasia belina, a popular indigenous edible insect commonly known as mopane worm, is a potential allergen of clinical and public health significance in Zimbabwe. This study was intended to assess the plausibility and feasibility of this hypothesis with a view to evaluate the insect’s health impact in a larger study.Methods: The study participants included both male and female villagers aged 10 years and above in Gwanda district, Zimbabwe. Eligible participants who completed the household questionnaire were referred to the local clinic for skin prick tests and to measure lung function and allergic airway inflammation. Allergen sensitization patterns were evaluated using 10 different inhalant allergen extracts including an in-house preparation of mopane worm. Lung function was measured with a Koko Legend spirometer and fractional exhaled nitric oxide levels (FeNO) (NIOX VERO) were measured in participants with at least one abnormal spirometric parameter. Data was analysed using Stata version 13 software.Results: Of the 46 eligible participants that completed the household questionnaire, 17 went to the clinic giving a response rate of 37%. Majority who completed the questionnaire were adults (91%) and the children (9%) were all female. The prevalence of sensitization to Imbrasia belina was 50% and the prevalence ranged from 22% to 72% for the other allergens including cockroach, mosquito and house dust mites. The data collection tools were safe and well tolerated by participants with no adverse events reported. Self-reported respiratory symptoms, abnormal lung function and elevated FeNO were recorded amongst participants sensitised to mopane worm.Conclusion: Pre-defined feasibility criteria were met with the exception of a lower than expected response rate for clinic data collection in this pilot study. For the main study, an increase in the sample size and more consistent community engagement will be applied to improve the response rates.

DNA barcoding reveals incorrect labelling of insects sold as food in the UK

Background Insects form an established part of the diet in many parts of the world and insect food products are emerging into the European and North American marketplaces. Consumer confidence in product is key in developing this market, and accurate labelling of content identity is an important component of this. We used DNA barcoding to assess the accuracy of insect food products sold in the UK. Methods We purchased insects sold for human consumption from online retailers in the UK and compared the identity of the material ascertained from DNA barcoding to that stated on the product packaging. To this end, the COI sequence of mitochondrial DNA was amplified and sequenced, and compared the sequences produced to reference sequences in NCBI and the Barcode of Life Data System (BOLD). Results The barcode identity of all insects that were farmed was consistent with the packaging label. In contrast, disparity between barcode identity and package contents was revealed in two cases of foraged material (mopane worm and winged termites). One case of very broad family-level description was also highlighted, where material described as grasshopper was identified as Locusta migratoria from DNA barcode. Conclusion Overall these data indicate the need to establish tight protocols to validate product identity in this developing market. Maintaining biosafety and consumer confidence rely on accurate and consistent product labelling that provides a clear chain of information from producer to consumer.