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PubMedDate not supplied

Life-threatening facial edema due to pine caterpillar mimicking an allergic event.

BACKGROUND: Approximately 150 species of Lepidoptera have been described as causing damage to human skin. One of these species is the pine processionary caterpillar, which is responsible for dermatitis, contact urticaria, ocular lesions and rarely respiratory signs and anaphylactic reactions through IgE-mediated or non-IgE-mediated mechanisms. We report a pediatric case of severe orofacial edema mimicking an allergic reaction after ingestion of a pine processionary caterpillar; urgent airway intubation was required. CASE REPORT: A 15-month-old boy was sleeping under a pine tree when his mother noted a pine caterpillar on his tongue. Because of rapidly developing facial swelling and respiratory distress, the infant was first taken to a local hospital where he received intravenous dexamethasone and pheniramine hydrogen maleate. On arrival at our emergency department, diffuse swelling and edema involving the tongue, perioral, nasal and perimandibular regions, and neck was noted, requiring urgent orotracheal intubation. There were no findings of anaphylaxis. The results of skin prick tests and specific IgE to common aero- and food allergens were negative. A skin prick test with extract of pine caterpillar was also negative. Prednisolone and pheniramine hydrogen maleate were administered for 7 days. The child gradually improved and was successfully extubated 4 days later. CONCLUSION: Although oral contact with a pine processionary caterpillar in the form of ingestion is rare, it may cause significant local reaction and airway compromise mimicking an allergic event. In this situation, early intubation to maintain airway patency is a life-saving measure.

Airway Obstruction↗
PubMed1999

Induction of IgE responses using a recombinant mosquito salivary allergen rAed a 2 without adjuvant in mice.

BACKGROUND: Reactions to mosquito bites are a global problem. Several salivary proteins from Aedes (Ae.) aegypti, the most common mosquito species, have been cloned and expressed. Plasmid DNA vaccination has been shown to be effective in the downregulation of IgE responses. To investigate the in vivo antigenicity of these recombinant proteins and to study the mechanisms underlying plasmid DNA vaccination, a mouse model sensitized with a recombinant antigen has been developed. METHODS: BALB/c and C57BL/6 mice were injected intradermally with a 37-kD recombinant Ae. aegypti salivary allergen (rAed a 2) in the absence of adjuvant twice weekly for 8 weeks and then challenged twice with rAed a 2 at weeks 10 and 12. Serum rAed a 2-specific IgE, IgG1 and IgG2a were measured by ELISA. Intradermal tests were performed every 4 weeks. The binding capacity of rAed a 2-specific IgE to the native Aed a 2 was examined by immunoblotting. RESULTS: In both strains, sensitization with rAed a 2 induced a significant increase in IgE and IgG1, but not IgG2a. In all sensitized mice, a positive immediate skin reaction was apparent, while delayed-type hypersensitivity reactions were not observed. BALB/c mice produced significantly higher levels of IgE and IgG1 and larger wheals than C57BL/6 mice. The IgE antibodies elicited by rAed a 2 bound to not only rAed a 2 but also its natural form in mosquito saliva. CONCLUSION: (1) Repeated injections of rAed a 2 without adjuvant induce predominant Th2-type responses in mice. (2) BALB/c mice are better responders for IgE production than C57BL/6 mice. (3) rAed a 2 has identical allergenicity to its natural form.

Adjuvants, Immunologic↗
PubMed2001

Insect bite reactions: an update.

Contact with insects may induce cutaneous or systemic reactions, ranging from little more than annoying to life threatening. The diagnosis depends on maintaining a high index of suspicion and being familiar with the insect fauna of the patient's environment and area of travel.

Animals↗
PubMedDate not supplied

Mosquito allergy: recombinant mosquito salivary antigens for new diagnostic tests.

In patients with mosquito allergy, lack of a readily available, sensitive, specific, safe test is the major obstacle to accurate diagnosis. Three recombinant mosquito salivary antigens, rAed a 1 (68 kD), rAed a 2 (37 kD) and rAed a 3 (30 kD), from Aedes aegypti have been cloned, expressed, purified and characterized. All three recombinant antigens are shared by Aedes vexans and other mosquito species, and all have been found to have biologic activity in humans. In recent studies, 43% of 28 mosquito bite test-positive subjects had a positive skin test to rAed a 1, 11% to rAed a 2 and 32% to rAed a 3. The sizes of the skin test reactions to the recombinant antigens correlated with the sizes of the A. aegypti bite test reactions. None of 15 A. aegypti bite test-negative subjects had a positive skin test to any of the recombinant antigens. Recombinant mosquito salivary antigens will facilitate the diagnosis of mosquito allergy.

Aedes↗
PubMed2004

Mosquito allergy: immune mechanisms and recombinant salivary allergens.

Reactions to mosquito bites are immunological in nature, with the involvement of IgE-, IgG- and T lymphocyte-mediated hypersensitivities. Acquired desensitization to mosquito saliva may occur during childhood and adolescence or during long-term exposure to mosquito bites. Due to the lack of salivary preparations, allergic reactions to mosquito bites are underdiagnosed and undertreated. Recombinant mosquito saliva allergens with biological activity are being developed. These recombinant allergens will significantly improve diagnosis of mosquito allergy and eventually will also improve specific immunotherapy for patients with systemic reactions to mosquito bites.

Adolescent↗
PubMed2006

Seasonal and temporal variations in the population and biting habit of mosquitoes on the Atlantic coast of Lagos, Nigeria.

OBJECTIVES: To determine the hourly density of vector mosquitoes in coastal Nigeria, compare seasonal human-biting and sporozoite rates in the vector density, locate breeding sites of mosquitoes, and determine larval population at breeding sites. MATERIALS AND METHODS: Indoor and outdoor mosquitoes of a coastal Nigerian community were caught during early and late wet seasons and in the harmattan period, a time of dusty wind from the Sahara on the western coast of Africa. Larvae were collected from various locations during the study period. The mosquitoes were physically characterized and their salivary glands dissected for sporozoite rate. Larvae density was calculated. Human-biting rate was calculated for Anopheles gambiae complex. RESULTS: Of the 4,317 female A. gambiae complex collected during the night bait catches, 3,543 (82.1%) were from outdoors and 774 (17.9%) from indoors during the three seasons. The maximum human-biting rate approached 25/h and the sporozoite rate was almost 3.0%. These vector mosquitoes were mainly outdoor biting and midnight feeding. Of the 1,269 Anopheles mosquitoes collected with pyrethrum spray catches, 1,245 (98.1%) were A. gambiae complex. There was no significant difference in the entomological inoculation or sporozoite rates during the three seasons of study. There was a preponderance of A. gambiae complex larvae from larval collection. CONCLUSION: Findings from this study should be useful in the implementation of Integrated Vector Management for the control of malaria in coastal and noncoastal areas of Nigeria.

Animals↗
PubMedDate not supplied

Predictors of injury among 1638 riders in a recreational long-distance bicycle tour: Cycle Across Maryland.

To assess the incidence of and risk factors for injuries in a group of bicyclists with a well-defined exposure to bicycling, we conducted a prospective study of 1638 recreational bicyclists who rode in the 6-day 339-mile Cycle Across Maryland tour in 1994. The mean age of participants was 39 years (range, 7 to 79), and two-thirds were male. All riders wore helmets. During the tour there were 85 acute traumatic injuries (15.4 per 100,000 person-miles), 76 overuse injuries (13.7 per 100,000 person-miles), and 37 other medical problems (6.7 per 100,000 person-miles). Acute traumatic injuries were associated with a history of racing versus none (relative risk = 2.2, 95% confidence limits = 1.3, 3.7) and with inexperience, no previous Cycle Across Maryland tours versus one or more (relative risk = 1.7, 95% confidence limits = 1.04, 2.8), but not with sex, training, or prior injuries. Inexperience and lack of preride conditioning were risk factors for overuse injuries. The most common overuse injuries and medical problems were knee pain, hand or wrist numbness, foot blisters, insect stings and bites, and heat and dehydration. Study results provide exposure-based incidence rates of bicyclist injuries and suggest overuse injuries may be reduced by increased preride conditioning.

Adolescent↗
PubMed1992

A pattern of acute poisoning in children in urban Zimbabwe: ten years experience.

1. A retrospective analysis was performed to evaluate the epidemiology of poisoning in children based on admissions to six of Zimbabwe's main urban hospitals over a 10-year period from 1980 to 1989 inclusive. 2. A total of 2873 cases were children aged between 0-15 years. This constituted 47.8% of poisoning cases from all age groups (6018) recorded during the study period. 3. All of the children (0-15 years) had signs and symptoms of poisoning on admission and, depending on their severity, were admitted to a ward or to an intensive care unit. A total of 4.9% (141) died. Most of those who died were suicide cases among the 11-15 year age group and accidental poisonings among the 0-15 year old group. 4. The under 0-5 age group constituted the majority of cases (75.4%) in the 0-15 age group, and most were between 1 and 3 years old. The 6-10 and 11-15 age groups formed 12.6% and 12% of the cases, respectively. The sex distribution showed that 53.1% were male. 5. Most incidences were accidental (93.2%). Suicides and parasuicides accounted for 1.9% and there were only two homicides. 6. The commonest toxic agents were: household products (27.2%), traditional medicines (23.%), venoms from snake bites and insect stings (16%) and therapeutic agents (12.4%). Of the therapeutic agents the most frequently implicated were antipsychotics 18.9%, analgesics 16.8%, anti-infectives 11.7%, anticonvulsants (8.2%) and benzodiazepines (7.7%).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed2004

Mosquito repellency of the seeds of celery (Apium graveolens L.).

When the mosquito repellencies of four fractions of Apium graveolens seeds (one hexane, two dichloromethane and one methanolic) were investigated in the laboratory, all four were found to offer human volunteers some protection against female, adult Aedes aegypti. The hexane fraction, however, was found to exhibit the highest repellency in the laboratory, with median effective doses (ED50) and ED95 of 0.41 and 2.93 mg/cm2 skin, respectively. Only this fraction, which was also found to provide protection against mosquito bites for 3.5 h when applied, in the laboratory, at a concentration of 250 mg/ml, was then investigated for its repellency in the field and its stability. In storage, it was found to retain its repellency for at least 2 months, although significant reductions in its repellency were observed (in terms of shortened complete-protection times) after 3 months, whatever the temperature of storage (-20 degrees C, 4 degrees C, or room temperature). When applied to the skin of volunteers under field conditions, the hexane fraction showed strong repellent activity against a wide range of mosquito species belonging to various genera (Ae. gardnerii, Ae. lineatopennis, Armigeres subalbatus, Culex tritaeniorhynchus, Cx. vishnui group, Cx. quinquefasciatus and Mansonia uniformis). It appeared not to cause dermal irritation or any other adverse effect, either during 6 months of use or in the following 3 months of follow-up. Mosquito repellents based on extracts of Ap. graveolens seeds could be developed commercially, as an effective personal-protection measure against mosquito bites and the diseases caused by mosquito-borne pathogens.

Adolescent↗
PubMed2004

Mosquitoes and transmission of malaria parasites - not just vectors.

The regional malaria epidemics of the early 1900s provided the basis for much of our current understanding of malaria epidemiology. Colonel Gill, an eminent malariologist of that time, suggested that the explosive nature of the regional epidemics was due to a sudden increased infectiousness of the adult population. His pertinent observations underlying this suggestion have, however, gone unheeded. Here, the literature on Plasmodium seasonal behaviour is reviewed and three historical data sets, concerning seasonal transmission of Plasmodium falciparum, are examined. It is proposed that the dramatic seasonal increase in the density of uninfected mosquito bites results in an increased infectiousness of the human reservoir of infection and, therefore, plays a key role in "kick-starting" malaria parasite transmission.

Age Factors↗
PubMed2006

Are insecticide-treated bednets more protective against Plasmodium falciparum than Plasmodium vivax-infected mosquitoes?

BACKGROUND: The outcomes of insecticide-treated bednet (ITN) interventions for malaria control in Papua New Guinea tend to suggest a differential protective effect against Plasmodium falciparum and Plasmodium vivax. Little is known about the impact of ITNs on the relative abundance of mosquitoes infected with either P. falciparum or P. vivax. This paper describes the biting cycle of P. falciparum and P. vivax-infected mosquitoes and the impact of an ITN intervention on the proportion of mosquitoes infected with either parasite species. METHODS: Entomological investigations were performed in East Sepik (ESP) and New Ireland Provinces (NIP) of PNG. Mosquitoes were collected using the all-night (18:00-06:00) landing catch and CDC light-trap methods and species specific malaria sporozoite rates were determined by ELISA. RESULTS AND DISCUSSION: The distribution of sporozoite positive mosquitoes in three four-hour periods (18:00-22:00, 22:00-02:00 & 02:00-06:00) showed that a higher proportion of P. vivax-infected mosquitoes were biting before people retired to bed under the protection of bednets. In the intervention village, the 308 mosquitoes collected before ITNs were introduced included eight (2.0%) P. falciparum-positive and four (1.0%) P. vivax-positive specimens, giving a parasite ratio of 2:1. The sporozoite rate determined from 908 mosquitoes caught after ITNs were introduced showed a significant decrease for P. falciparum (0.7%) and a slight increase for P. vivax (1.3%), resulting in a post intervention parasite ratio of 1:2. In the East Sepik Province, where ITNs were not used, P. falciparum remained the dominant species in 12 monthly mosquito collections and monthly P. falciparum:P. vivax formula varied from 8:1 to 1.2:1. CONCLUSION: These findings suggest that people sleeping under treated bednets may be more exposed to P. vivax than P. falciparum-infected mosquitoes before going to sleep under the protection of bednets. This difference in the biting behaviour of mosquitoes infected with different malaria parasites may partly explain the change in the P. falciparum:P. vivax formula after the introduction of ITNs.

Animals↗