The biting rate of Aedes aegypti and its variability: A systematic review (1970-2022).

BACKGROUND: Transmission models have a long history in the study of mosquito-borne disease dynamics. The mosquito biting rate (MBR) is an important parameter in these models, however, estimating its value empirically is complex. Modeling studies obtain biting rate values from various types of studies, each of them having its strengths and limitations. Thus, understanding these study designs and the factors that contribute to MBR estimates and their variability is an important step towards standardizing these estimates. We do this for an important arbovirus vector Aedes aegypti. METHODOLOGY/PRINCIPAL FINDINGS: We perform a systematic review using search terms such as 'biting rate' and 'biting frequency' combined with 'Aedes aegypti' ('Ae. aegypti' or 'A. aegypti'). We screened 3,201 articles from PubMed and ProQuest databases, of which 21 met our inclusion criteria. Two broader types of studies are identified: human landing catch (HLC) studies and multiple feeding studies. We analyze the biting rate data provided as well as the methodologies used in these studies to characterize the variability of these estimates across temporal, spatial, and environmental factors and to identify the strengths and limitations of existing methodologies. Based on these analyses, we present two approaches to estimate population mean per mosquito biting rate: one that combines studies estimating the number of bites taken per gonotrophic cycle and the gonotrophic cycle duration, and a second that uses data from histological studies. Based on one histological study dataset, we estimate biting rates of Ae. aegypti (0.41 and 0.35 bite/mosquito-day in Thailand and Puerto Rico, respectively). CONCLUSIONS/SIGNIFICANCE: Our review reinforces the importance of engaging with vector biology when using mosquito biting rate data in transmission modeling studies. For Ae. aegypti, this includes understanding the variation of the gonotrophic cycle duration and the number of bites per gonotrophic cycle, as well as recognizing the potential for spatial and temporal variability. To address these variabilities, we advocate for site-specific data and the development of a standardized approach to estimate the biting rate.

Envenomation From Flood-Related Fire Ant Rafting: A Cautionary Note.

BACKGROUND: Imported fire ants aggressively sting humans, leading to a variety of local and systemic effects. Fire ants display a behavioral adaptation to survive flooding, called "rafting," bringing humans into even more contact with fire ants. METHODS: To assess frequency of encounters with fire ant rafts, duck hunters on the website "Duck Hunter's Forum" were asked about their experiences with the ants while wading or boating in flooded areas. All members of the group received a brief explanation and asked to respond directly if they had had such an encounter. They were then asked to fill out a short 6-question survey. RESULTS: There were 2021 views of the thread about fire ant raft encounters, with 35 (1.7%) responses. Twenty-four (68.6%) said they had experienced encounters with fire ant rafts. Six responders described purposely or inadvertently physically touching the rafts with their body parts, boat, or a paddle, causing the ants to enter their boat or to climb directly onto the hunter(s). Five respondents were stung (number of stings from "a few" to 50), describing reactions to stings as "small pustules," "whelps," and "pimple-like, puss-filled whelps." CONCLUSIONS: These results confirm that fire ant rafts formed during flooding present a potential hazard to persons walking, wading, or boating in those areas. We suggest that these rafts are an under-appreciated health hazard. It is reasonable to assume that people in flooded areas occasionally contact these floating rafts and are stung multiple times. We provide preliminary prevention/protection recommendations for health professionals, to be shared with their patients and the general public.

Severe Systemic Reactions Following Bee Sting Injuries in Korea.

PURPOSE: Most bee sting injuries are benign, although sometimes they can result in life threatening outcomes, such as anaphylaxis and death. The purpose of this study was to investigate the epidemiologic status of bee sting injuries in Korea and to identify risk factors associated with severe systemic reactions (SSRs). MATERIALS AND METHODS: Cases were extracted from a multicenter retrospective registry for patients who had visited emergency departments (EDs) for bee sting injuries. SSRs were defined as hypotension or altered mental status upon ED arrival, hospitalization, or death. Patient demographics and injury characteristics were compared between SSR and non-SSR groups. Logistic regression was performed to identify risk factors for bee sting-associated SSRs, and the characteristics of fatality cases were summarized. RESULTS: Among the 9673 patients with bee sting injuries, 537 had an SSR and 38 died. The most frequent injury sites included the hands and head/face. Logistic regression analysis revealed that the occurrence of SSRs was associated with male sex [odds ratio (95% confidence interval); 1.634 (1.133-2.357)] and age [1.030 (1.020-1.041)]. Additionally, the risk of SSRs from trunk and head/face stings was high [2.858 (1.405-5.815) and 2.123 (1.333-3.382), respectively]. Bee venom acupuncture [3.685 (1.408-9.641)] and stings in the winter [4.573 (1.420-14.723)] were factors that increased the risk of SSRs. CONCLUSION: Our findings emphasize the need for implementing safety policies and education on bee sting-related incidents to protect high-risk groups.

Validity of Self-Reported Mosquito Bites to Assess Household Mosquito Abundance in Six Communities of Esmeraldas Province, Ecuador.

Mosquito-borne diseases are a global burden; however, current methods of evaluating human-mosquito contact rates are expensive and time consuming. Validated surveys of self-reported mosquito bites may be an inexpensive way to determine mosquito presence and bite exposure level in an area, but this remains untested. In this study, a survey of self-reported mosquito bites was validated against household mosquito abundance from six communities in Esmeraldas, Ecuador. From February 2021 to July 2022, households were interviewed monthly, and five questions were used to ask participants how often they were bitten by mosquitoes at different times during the day. At the same time, adult mosquitoes were collected using a Prokopack aspirator. Species were identified and counted. Survey responses were compared with the total number of mosquitoes found in the home using negative binomial regression. More frequent self-reported mosquito bites were significantly associated with higher numbers of collected adult mosquitoes. These associations were driven by the prevalence of the dominant genera, Culex. These results suggest that surveys of perceived mosquito bites relate to actual mosquito presence, making them a potentially useful tool for determining the impact of vector-control interventions on community perceptions of risk but less useful for assessing the risk of nondominant species such as Aedes aegypti. Further work is needed to examine the robustness of these results in other contexts.

Onchocerciasis transmission status in some endemic communities of Cross River State, Nigeria after two decades of mass drug administration with ivermectin.

Onchocerciasis is a parasitic disease transmitted by black flies. Human onchocerciasis is a public health and socioeconomic problem in Nigeria. Its prevalence and morbidity have reduced over the years because of control efforts especially, Mass Drug Administration with ivermectin. The current goal is to eliminate the disease transmission by 2030. Understanding the changes in transmission patterns in Cross River State is critical to elimination of onchocerciasis in Nigeria. This study was designed to determine the transmission dynamics of onchocerciasis in Cross River State after over two decades of mass ivermectin distribution in endemic communities. Agbokim, Aningeje, Ekong Anaku and Orimekpang are four endemic communities from three Local Government Areas of the State selected for this study. Transmission indices such as infectivity rates, biting rates and transmission potentials, parity rates and diurnal biting activities were determined. A total of 15,520 adult female flies were caught on human baits, Agbokim (2831), Aningeje (6209), Ekong Anaku (4364) and Orimekpang (2116). A total of 9488 and 5695 flies were collected during the rainy and dry seasons respectively in the four communities studied. The differences in relative abundance among the communities were statistically significant (P < 0.001). Monthly and seasonal fly numbers varied significantly (P < 0.008). There were differences in diurnal biting activities of flies in this study at different hours of the day and different months. The peak monthly biting rates were 5993 (Agbokim, October), 13,134 (Aningeje, October), 8680 (Ekong Anaku, October) and 6120 (Orimekpang, September) bites/person/month while the lowest monthly biting rates were 400 (Agbokim, November), 2862 (Aningeje, August), 1405 (Ekong Anaku, January) and 0.0 (Orimekpang, November and December) bites/person/month. Differences in biting rates among the study communities were significant (P < 0.001). The peak monthly transmission potential in Aningeje was 160 infective bites/person/month in the month of February while the lowest (except for months with no transmission) was 42 infective bites/person/month in the month of April. All other study sites had no ongoing transmission in this study. Transmission studies showed that there is progress toward transmission interruption especially in 3 out of the four studied areas. Molecular O-150 poolscreen studies is required to confirm the true transmission situation in the areas.

Outcomes of wasp and bee stings in Taiwan.

BACKGROUND: The families of Hymenoptera causing commonly poisonous animal stings in Taiwan include Apoidea (bee) and Vespidae (wasp). This study aimed to investigate the epidemiologic, clinical characteristics, and outcomes of the severity of envenomation following wasp or bee stings in Taiwan. METHODS: We conducted a retrospective study by identifying all wasp and bee sting-related envenomation reported to the Taiwan National Poison Control Center between January 2001 and November 2021. Data were reviewed and abstracted by two independent reviewers. We then used ordinal logistic regression analysis to find potential predictors of severe wasp and bee sting-related envenomation. RESULTS: In Taiwan, bee or wasp stings mainly occur in late summer and autumn. A total of 611 patients were reported to the Taiwan National Poison Control Center with 7.5% resulting in severe or fatal envenomation. Four-hundred and forty-one patients were eligible for the final analysis of the predictors of severity. Logistic regression analysis showed that a greater number of stings, being stung by wasps, older age, and stings over the body were significant predictors for greater severity. The systemic effects following wasp and bee sting included anaphylactic reaction, prolongation of activated partial thromboplastin time, rhabdomyolysis, acute kidney injury, and elevated liver enzymes. CONCLUSIONS: Wasps generally inflicted more severe envenomation than bees. Only 7.5% of patients had severe or fatal outcomes. Patients with older age, multiple stings, and/or multiple sites of stings were more likely to have severe outcomes.

Epidemiological study of bee stings in the state of Paraiba, Northeastern Brazil, from 2015 to 2019

INTRODUCTION: In Brazil, envenomation by bee sting is a public health problem due to its incidence in all regions of the country, as well as the severity of cases. Despite the medical and sanitary importance, the literature on this topic in Brazil is scarce, in the Northeast region. OBJECTIVE: To describe the epidemiological characteristics of bee stings in Paraíba, in the Northeast region of Brazil, from 2015 to 2019. METHODS: The current study is a descriptive and retrospective epidemiological investigation conducted through the recovery of secondary data made available by the database from the Ministry of Health Notification Information System. RESULTS: A total of 1,151 cases were analyzed, and they were reported during all the months of the period of the study and were more frequent in the regions Agreste and Sertão of the Paraíba. The victims were men aged 20 to 59 years. Most individuals received medical assistance within 3 hours of the incident. The cases were classified as mild and progressed to cure. CONCLUSION: In Paraíba, bee stings have increased in recent years, especially in regions with a semi-arid climate. In addition, this study provides data that may be used in the development of educational health actions to promote the prevention and control of bee stings in this region.

Human behavior determinants of exposure to Anopheles vectors of malaria in Sumba, Indonesia.

Malaria vector control interventions in Sumba, Indonesia, have not been able to eliminate malaria. Human drivers of exposure to Anopheles bites were investigated as part of a larger clinical trial evaluating the impact of a spatial repellent product on malaria incidence. Human behavioral observations (HBOs) evaluating temporal and spatial presence, sleeping behaviors, and insecticide treated net (ITN) use, were collected parallel to entomological collections-indoor and outdoor human landing catches (HLCs), and house hold surveys. Data demonstrates that mosquito access to humans, enabled by structurally open houses, is evident by the similar entomological landing rates both inside and outside households. The presence of animals inside houses was associated with increased mosquito entry-however, the number of humans present inside houses was not related to increased mosquito landing. Analyzing mosquito landing rates with human behavior data enables the spatial and temporal estimation of exposure to Anopheles bites, accounting for intervention (ITN) presence and usage. Human behavior adjusted exposure to Anopheles bites was found to be highest in the early in the evening, but continued at lower levels throughout the night. Over the night, most exposure (53%) occurred when people were indoors and not under the protection of nets (asleep or awake) followed by exposure outside (44%). Characterized gaps in protection are outdoor exposure as well as exposure indoors-when awake, and when asleep and not using ITNs. Interestingly, in the primary trial, even though there was not a significant impact of the spatial repellent on vector biting rates by themselves (16%), when factoring in human behavior, there was approximately 28% less exposure in the intervention arm than in the placebo arm. The treated arm had less human behavior adjusted bites in all spaces evaluated though there was proportionally higher exposure indoors. This analysis points to the importance of using HBOs both towards understanding gaps in protection as well as how interventions are evaluated. To mitigate ongoing transmission, understanding context specific spatial and temporal exposure based on the interactions of vectors, humans and interventions would be vital for a directed evidence-based control or elimination strategy.

Human IgG responses to Aedes mosquito salivary peptide Nterm-34kDa and its comparison to Anopheles salivary antigen (gSG6-P1) IgG responses measured among individuals living in Lower Moshi, Tanzania.

BACKGROUND: The level of human exposure to arbovirus vectors, the Aedes mosquitoes, is mainly assessed by entomological methods which are labour intensive, difficult to sustain at a large scale and are affected if transmission and exposure levels are low. Alternatively, serological biomarkers which detect levels of human exposure to mosquito bites may complement the existing epidemiologic tools as they seem cost-effective, simple, rapid, and sensitive. This study explored human IgG responses to an Aedes mosquito salivary gland peptide Nterm-34kDa in Lower Moshi, a highland area with evidence of circulating arboviruses and compared the Aedes IgG responses to Anopheles mosquitoes' salivary antigen (GSG6-P1) IgG responses. METHODS: Three cross-sectional surveys were conducted in 2019: during the first dry season in March, at the end of the rainy season in June and during the second dry season in September in five villages located in Lower Moshi. Blood samples were collected from enrolled participants above six months of age (age span: 7 months to 94 years) and analysed for the presence of anti-Nterm-34kDa IgG antibodies. Possible associations between Nterm-34kDa seroprevalence and participants' characteristics were determined. Levels of IgG responses and seroprevalence were correlated and compared to the already measured IgG responses and seroprevalence of Anopheles mosquitoes' salivary antigen, GSG6-P1. RESULTS: During the first dry season, Nterm-34kDa seroprevalence was 34.1% and significantly increased at the end of the rainy season to 45.3% (Chi square (χ2) = 6.42 p = 0.011). During the second dry season, the seroprevalence significantly declined to 26.5% (χ2 = 15.12 p<0.001). During the rainy season, seroprevalence was significantly higher among residents of Oria village (adjusted odds ratio (AOR) = 2.86; 95% CI = 1.0-7.8; p = 0.041) compared to Newland. Moreover, during the rainy season, the risk of exposure was significantly lower among individuals aged between 16 and 30 years (AOR = 0.25; 95% CI = 0.1 = 0.9; p = 0.036) compared to individuals aged between 0 and 5 years. There was weak to moderate negative correlation between N-term 34kDa IgG and gSG6-P1 antigens. N-term 34kDa seroprevalence were higher compared to gSG6-P1 seroprevalence. CONCLUSION: The findings of this study support that IgG antibody responses towards the Aedes mosquito salivary peptide Nterm-34kDa are detectable among individuals living in lower Moshi and vary with season and geographical area. More individuals are exposed to Aedes mosquito bites than Anopheles mosquito and those exposed to Aedes bites are not necessarily exposed to Anopheles mosquitoes.

Semi-field evaluation of human landing catches versus human double net trap for estimating human biting rate of Anopheles minimus and Anopheles harrisoni in Thailand.

Background: Whilst the human landing catch (HLC) technique is considered the 'gold standard' for estimating human-biting rates, it is labor-intensive and fraught with potential risk of exposure to infectious mosquito bites. This study evaluated the feasibility and performance of an alternative method, the human double net trap (HDNT) relative to HLC for monitoring host-seeking malaria vectors of the Anopheles minimus complex in a semi-field system (SFS). Methods: HDNT and HLC were positioned in two rooms, 30 m apart at both ends of the SFS. Two human volunteers were rotated between both traps and collected released mosquitoes (n = 100) from 6:00 pm till 6:00 am. Differences in Anopheles mosquito densities among the trapping methods were compared using a generalized linear model based on a negative binomial distribution. Results: There were 82.80% (2,136/2,580) of recaptures of wild-caught and 94.50% (2,835/3,000) of laboratory-reared mosquitoes that were molecularly identified as An. harrisoni and An. minimus, respectively. Mean density of An. harrisoni was significantly lower in HNDT (15.50 per night, 95% CI [12.48-18.52]) relative to HLC (25.32 per night (95% CI [22.28-28.36]), p < 0.001). Similarly, the mean density of a laboratory strain of An. minimus recaptured in HDNT was significantly lower (37.87 per night, 95% CI [34.62-41.11]) relative to HLC (56.40 per night, 95% CI [55.37-57.43]), p < 0.001. Relative sampling efficiency analysis showed that HLC was the more efficient trap in collecting the An. minimus complex in the SFS. Conclusion: HDNT caught proportionately fewer An. minimus complex than HLC. HDNT was not sensitive nor significantly correlated with HLC, suggesting that it is not an alternative method to HLC.

From Insect Bites to a Skin Autoimmune Disease: A Conceivable Pathway to Endemic Pemphigus Foliaceus.

In the endemic variants of pemphigus foliaceus (PF), in Brazil and Tunisia, patients generate pathogenic IgG4 anti-desmoglein 1 autoantibodies. Additionally, these patients possess antibodies against salivary proteins from sand flies that react with Dsg1, which may lead to skin disease in susceptible individuals living in endemic areas. This minireview focuses on recent studies highlighting the possible role of salivary proteins from Lutzomyia longipalpis (L. longipalpis) in EPF from Brazil and Phlebotomus papatasi (P. papatasi) in EPF from Tunisia. We will briefly discuss the potential mechanisms of molecular mimicry and epitope spreading in the initiation and development of endemic PF (EPF) in Brazil and Tunisia.

Epidemiological study of the bee stings in the state of Bahia, northeastern Brazil, from 2010 to 2019 / Estudo epidemiológico dos acidentes por picada de abelha no estado da Bahia, nordeste do Brasil, de 2010 a 2019

Introduction: envenomation and deaths by bee stings have increased in all regions of Brazil. However, there are few epidemiological studies on them, especially in the states of northeastern Brazil. Objective: to determine the epidemiological characteristics of bee stings in the state of Bahia, Northeastern Brazil, from 2010 to 2019. Methodology: this is a descriptive and analytical epidemiological study conducted through a retrospective survey of secondary data provided by the database of the Notifiable Diseases Information System of the Ministry of Health. Results: between 2010 and 2019, a total of 7,979 cases were analyzed. Incidents were distributed in 356 municipalities, with the highest frequency in the regions of Agreste and Sertão da Bahia. Cases occurred in all months of the investigated years, with a greater occurrence in urban areas, affecting mainly adult men. The anatomical region of the body most affected by the sting was the head and most cases received medical care within 3 hours after the incident. Local manifestations were more frequent than systemic ones. The injuries were predominantly classified as mild and progressed to cure. Conclusions: the high number of cases and their extensive spatial distribution reveal that bee stings may be considered an emerging and neglected public health problem in the state of Bahia.

Introdução: os acidentes e os óbitos causados por picada de abelha têm aumentado em todas as regiões do Brasil. Contudo, existem poucos estudos epidemiológicos sobre acidentes com abelha, principalmente nos estados do Nordeste do Brasil. Objetivo:determinar as características epidemiológicas do acidente por picada de abelha no estado da Bahia, Nordeste do Brasil, de 2010 a 2019. Metodologia: trata-se de um estudo epidemiológico descritivo e analítico realizado por meio de uma pesquisa retrospectiva de dados secundários disponibilizados pelo banco de dados do Sistema de Informação de Agravos de Notificação do Ministério da Saúde. Resultados: entre 2010 e 2019, um total de 7.979 casos foi analisado. Os acidentes foram distribuídos em 356 municípios, com a maior frequência nas regiões do Agreste e do Sertão da Bahia. Os casos ocorreram em todos os meses dos anos investigados, com maior ocorrência em áreas urbanas, afetando principalmente homens adultos. A região anatômica do corpo mais atingida pela picada foi a cabeça e a maioria dos casos recebeu assistência médica até 3 horas após o incidente. As manifestações locais foram mais frequentes do que as sistêmicas. Os agravos foram predominantemente classificados como leve e progrediram para a cura. Conclusões: o elevado número de casos e a sua extensa distribuição espacial revelam que o acidente causado por picada de abelha pode ser considerado um emergente negligenciado problema de saúde pública no estado da Bahia.

Natural History of the Hymenoptera Venom Sensitivity Reactions in Adults: Study Design.

BACKGROUND: Allergic reactions to Hymenoptera stings can have varying levels of severity, according to the Müller grading system. METHODS: By an epidemiological concept, this is a retrospective cohort study. The observed cohort was represented by patients referred to the University Clinic Golnik due to Hymenoptera allergic reaction in the period from 1997 to 2015. From the immunological database of the University Clinic Golnik, we obtained laboratory data (sIgE, skin tests and basophil activation test). The clinical characteristics of patients were obtained from BIRPIS. With the help of a questionnaire, which was sent to each patient in the period from May 2019 to April 2021, we obtained epidemiological data. For the assessment of the association between the severity of allergic reaction for the observed outcome, the severity of the first allergic reaction after Hymenoptera sting was used. Other variables were grouped according to risk factors. DISCUSSION: We will identify the risk factors that could play an important role in a severe systemic reaction: the aetiology of the Hymenoptera sting, sex, age, history and severity of previous systemic reactions, being re-stung in an interval of two months, the frequency of re-stings, atopy, genetic predisposition, preventive medication use, other medication use, beekeeping or living next to beehives and why immunotherapy was not taken. Laboratory data will also be analysed to determine if there is any association with laboratory tests and the severity of the allergic reactions after Hymenoptera stings. CONCLUSIONS: Several new approaches are introduced in the study design. The most important is that the protocol covers epidemiological data gained from the questionnaire, as well as clinical data gained from the Immunological database and BIRPIS database. We expect to obtain significant results that will explain the risk factors for the natural history of Hymenoptera sting allergic reactions and will help allergologists, as well as general doctors, when facing those patients allergic to Hymenoptera venom without immunotherapy.

Social wasps in Spain: the who and where.

OBJECTIVE: The objective of this study was to list the social vespids occurring in Spain, determine their presence in each region, and correlate the data with the vespids responsible for allergic reactions and their progression over time. METHODS: Insects distribution data were collected in two phases: from the southern half of Spain (2008-2012), and from the northern half of Spain (2016-2019). Data for the vespids were collected from the prescriptions of Hymenoptera venom immunotherapy (HVIT) at six Spanish hospitals in the years 2009 and 2019. RESULTS: Polistes dominula and Vespula germanica were the most widely distributed species. Vespa velutina was found to be present in a large part of northern Spain. During the 10 year period, the prescriptions of vespid VIT increased by 42.63%. The north of Spain saw a 3.61 fold greater predominance of prescriptions for Vespula (to some extent influenced by Vespa velutina allergy) whereas in central and southern Spain, there was a 3.97 fold greater predominance of prescriptions for Polistes. CONCLUSIONS: It is the first study that compares the vespid distribution maps with VIT prescription. A noteworthy finding is the wide presence of Polistes dominula and Vespula germanica in Spain and the appearance of Vespa velutina allergy in the northern part of the country. Data of HVIT prescriptions reflect inter-regional variability with the predominance of Vespula (due to Vespula and Vespa) in the north and that of Polistes in the center and south of Spain.

Social wasps in Spain: the who and where

Objective The objective of this study was to list the social vespids occurring in Spain, determine their presence in each region, and correlate the data with the vespids responsible for allergic reactions and their progression over time.Methods Insects distribution data were collected in two phases: from the southern half of Spain (2008–2012), and from the northern half of Spain (2016–2019). Data for the vespids were collected from the prescriptions of Hymenoptera venom immunotherapy (HVIT) at six Spanish hospitals in the years 2009 and 2019.Results Polistes dominula and Vespula germanica were the most widely distributed species. Vespa velutina was found to be present in a large part of northern Spain. During the 10 year period, the prescriptions of vespid VIT increased by 42.63%. The north of Spain saw a 3.61 fold greater predominance of prescriptions for Vespula (to some extent influenced by Vespa velutina allergy) whereas in central and southern Spain, there was a 3.97 fold greater predominance of prescriptions for Polistes.Conclusions It is the first study that compares the vespid distribution maps with VIT prescription. A noteworthy finding is the wide presence of Polistes dominula and Vespula germanica in Spain and the appearance of Vespa velutina allergy in the northern part of the country. Data of HVIT prescriptions reflect inter-regional variability with the predominance of Vespula (due to Vespula and Vespa) in the north and that of Polistes in the center and south of Spain (AU)

Demographic patterns of human antibody levels to Simulium damnosum s.l. saliva in onchocerciasis-endemic areas: An indicator of exposure to vector bites.

BACKGROUND: In onchocerciasis endemic areas in Africa, heterogenous biting rates by blackfly vectors on humans are assumed to partially explain age- and sex-dependent infection patterns with Onchocerca volvulus. To underpin these assumptions and further improve predictions made by onchocerciasis transmission models, demographic patterns in antibody responses to salivary antigens of Simulium damnosum s.l. are evaluated as a measure of blackfly exposure. METHODOLOGY/PRINCIPAL FINDINGS: Recently developed IgG and IgM anti-saliva immunoassays for S. damnosum s.l. were applied to blood samples collected from residents in four onchocerciasis endemic villages in Ghana. Demographic patterns in antibody levels according to village, sex and age were explored by fitting generalized linear models. Antibody levels varied between villages but showed consistent patterns with age and sex. Both IgG and IgM responses declined with increasing age. IgG responses were generally lower in males than in females and exhibited a steeper decline in adult males than in adult females. No sex-specific difference was observed in IgM responses. CONCLUSIONS/SIGNIFICANCE: The decline in age-specific antibody patterns suggested development of immunotolerance or desensitization to blackfly saliva antigen in response to persistent exposure. The variation between sexes, and between adults and youngsters may reflect differences in behaviour influencing cumulative exposure. These measures of antibody acquisition and decay could be incorporated into onchocerciasis transmission models towards informing onchocerciasis control, elimination, and surveillance.

Characterization of Anopheles gambiae D7 salivary proteins as markers of human-mosquito bite contact.

BACKGROUND: Malaria is transmitted when infected Anopheles mosquitoes take a blood meal. During this process, the mosquitoes inject a cocktail of bioactive proteins that elicit antibody responses in humans and could be used as biomarkers of exposure to mosquito bites. This study evaluated the utility of IgG responses to members of the Anopheles gambiae D7 protein family as serological markers of human-vector contact. METHODS: The D7L2, D7r1, D7r2, D7r3, D7r4 and SG6 salivary proteins from An. gambiae were expressed as recombinant antigens in Escherichia coli. Antibody responses to the salivary proteins were compared in Europeans with no prior exposure to malaria and lifelong residents of Junju in Kenya and Kitgum in Uganda where the intensity of malaria transmission is moderate and high, respectively. In addition, to evaluate the feasibility of using anti-D7 IgG responses as a tool to evaluate the impact of vector control interventions, we compared responses between individuals using insecticide-treated bednets to those who did not in Junju, Kenya where bednet data were available. RESULTS: We show that both the long and short forms of the D7 salivary gland antigens elicit a strong antibody response in humans. IgG responses against the D7 antigens reflected the transmission intensities of the three study areas, with the highest to lowest responses observed in Kitgum (northern Uganda), Junju (Kenya) and malaria-naïve Europeans, respectively. Specifically, the long form D7L2 induced an IgG antibody response that increased with age and that was lower in individuals who slept under a bednet, indicating its potential as a serological tool for estimating human-vector contact and monitoring the effectiveness of vector control interventions. CONCLUSIONS: This study reveals that D7L2 salivary antigen has great potential as a biomarker of exposure to mosquito bites and as a tool for assessing the efficacy of vector control strategies such as bednet use.

Management of Anaphylaxis in Infants and Toddlers.

Anaphylaxis is a systemic allergic reaction that can be caused by food, drugs, insect bites, or unknown triggers in infants and toddlers. Anaphylaxis rates are increasing. Infants and toddlers may have increased exposure to known and unknown allergens, decreased ability to describe their symptoms, and an expanded differential diagnosis for consideration on presentation. The most common symptoms in these age groups are cutaneous and gastrointestinal. Age-specific language may be helpful for caregivers to identify and describe the symptoms of anaphylaxis in infants and toddlers. Long-term management of anaphylaxis includes allergy evaluation to guide avoidance and assess prognosis and education on allergic reaction management; this incorporates the prescription of epinephrine autoinjector and provision of an allergy emergency plan.

Clinical effects and factors associated with adverse clinical outcomes of hymenopteran stings treated in a Thai Poison Centre: a retrospective cross-sectional study.

OBJECTIVE: To describe clinical effects and outcomes of hymenopteran stings and to explore the non-laboratory factors associated with adverse clinical outcomes, a composite outcome including death, respiratory failure requiring intubation, acute kidney injury (AKI) requiring dialysis and hypotension requiring vasopressor use. METHODS: A retrospective cross-sectional study was performed at the Ramathibodi Poison Center, a poison centre of a tertiary care hospital in Thailand. All cases of hymenopteran sting consultations from January 2015 to June 2019 were consecutively enrolled, and charts were reviewed. Demographics, initial clinical characteristics and outcomes were collected. Factors associated with adverse clinical outcome were explored. RESULTS: One hundred and fourteen hymenopteran stings cases (wasp 48%, bee 33%, hornet 14% and carpenter bee 8.8%) were included (median age, 36.5 years (interquartile range 9-55); male 63%). The prevalence of adverse clinical outcomes was 12.3% (95%CI 6.88-12.8). At initial presentation, 100% of cases had local skin reactions, 11.4% were clinical anaphylaxis, and 8% had red urine. Adverse clinical outcomes included death (n = 10), respiratory failure requiring intubation (n = 9), AKI requiring dialysis (n = 6) and hypotension requiring vasopressor use (n = 2). None of the patients with carpenter bee or hornet stings developed adverse clinical outcomes. In univariable analysis, urticaria, wheezing, red urine, wasp sting and sting number > 10 were significantly associated with adverse clinical outcomes. In multivariable analysis, red urine (adjusted OR 11.1 (95% CI 1.57-216)), wheezing (adjusted OR 16.7 (95% CI 1.43-402)) and a number of stings > 10 (adjusted OR 21.5 (95% CI2.13-2557)) were significant. CONCLUSIONS: Adverse clinical outcomes in hymenopteran stings were not uncommon among cases inquiring to a national Thai poison centre. At initial presentation, red urine, wheezing and a number stings >10 were significantly associated with adverse clinical outcomes. Larger epidemiologic studies are required to confirm these associations.

Tendência temporal e perfil epidemiológico dos acidentes por animais peçonhentos no Brasil, 2007-2019 / Tendencia temporal y perfil epidemiológico de los accidentes por animales venenosos en Brasil, 2007-2019 / Temporal trend and epidemiological profile of accidents involving venomous animals in Brazil, 2007-2019

Objetivo: Analisar a tendência temporal dos acidentes causados por animais peçonhentos no Brasil, de 2007 a 2019. Métodos: Estudo transversal, realizado com dados do Sistema de Informação de Agravos de Notificação (Sinan). Para a análise temporal, utilizou-se a regressão linear de Prais-Winsten. Foram calculadas as incidências por sexo e faixa etária, risco relativo e letalidade. Resultados: No período de estudo, houve 2.102.657 casos de acidentes por animais peçonhentos. Com exceção do ofidismo, os demais acidentes apresentaram tendência temporal crescente na maioria das macrorregiões nacionais. Escorpionismo, ofidismo e araneísmo foram responsáveis por 86% dos acidentes, principalmente entre pessoas do sexo masculino em idade economicamente ativa. A de letalidade foi mais elevada para acidentes ofídicos (0,4%) e apílicos (0,3%). As crianças foram as principais vítimas de acidentes com abelhas, lagartas e "outros". Conclusão: Os acidentes com animais peçonhentos apresentaram tendência temporal crescente para a maioria dos agravos e diferentes perfis epidemiológicos.

Objetivo: Analizar la tendencia temporal de los accidentes con animales ponzoñosos en Brasil de 2007 a 2019. Métodos: Estudio transversal realizado con datos del Sistema de Información de Enfermedades de Declaración Obligatoria (Sinan). Para el análisis temporal se utilizó la Regresión Lineal de Prais-Wisten. Se calcularon las incidencias por sexo y grupo de edad, riesgo relativo y letalidad. Resultados: Durante el período del estudio hubo 2.102.657 casos de accidentes con animales ponzoñosos. Con excepción de la mordedura de serpiente, los demás accidentes mostraron una tendencia temporal creciente en la mayoría de las regiones del país. El escorpionismo, la mordedura de serpiente y la picadura de araña fueron responsables del 86% de los accidentes, afectando principalmente a personas del sexo masculino en edad laboral. Las tasas de letalidad más altas fueron por accidentes de mordedura de serpiente (0,4%) y picadura de araña (0,3%). Los niños fueron las principales vitimas de los acidentes con abejas, lagartas y "otros". Conclusión: Los accidentes com animales ponzoñosos mostraron una tendencia temporal creciente para la mayoría de las enfermedades y diferentes perfiles epidemiológicos.

Objective: to analyze the temporal trend of accidents involving venomous animals in Brazil from 2007 to 2019. Methods: this was a cross-sectional study carried out with data from the Notifiable Health Conditions Information System (SINAN). Prais-Winsten linear regression was used for the temporal analysis. We calculated incidence rates according to sex and age group, relative risk and case fatality ratio. Results: during the study period there were 2,102,657 cases of accidents involving venomous animals. With the exception of snakebite, the remaining accidents showed a rising temporal trend in most regions of the country. Scorpion stings, snake bites and spider bites were responsible for 86% of accidents, mainly affecting male people of working age. Accidents involving snakes (0.4%) and bees (0.3%) had the highest case fatality ratios. Children were the main victims of accidents involving bees, caterpillars and "others". Conclusion: accidents involving venomous animals showed a rising temporal trend for most conditions, as well as different epidemiological profiles.