Publications by authors named "Justin O Schmidt"

29 Publications

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Venom chemistry underlying the painful stings of velvet ants (Hymenoptera: Mutillidae).

Cell Mol Life Sci 2021 May 10. Epub 2021 May 10.

Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia.

Velvet ants (Hymenoptera: Mutillidae) are a family of solitary parasitoid wasps that are renowned for their painful stings. We explored the chemistry underlying the stings of mutillid wasps of the genus Dasymutilla Ashmead. Detailed analyses of the venom composition of five species revealed that they are composed primarily of peptides. We found that two kinds of mutillid venom peptide appear to be primarily responsible for the painful effects of envenomation. These same peptides also have defensive utility against invertebrates, since they were able to incapacitate and kill honeybees. Both act directly on cell membranes where they directly increase ion conductivity. The defensive venom peptides of Dasymutilla bear a striking similarity, in structure and mode of action, to those of the ant Myrmecia gulosa (Fabricius), suggesting either retention of ancestral toxins, or convergence driven by similar life histories and defensive selection pressures. Finally, we propose that other highly expressed Dasymutilla venom peptides may play a role in parasitisation, possible in delay or arrest of host development. This study represents the first detailed account of the composition and function of the venoms of the Mutillidae.
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http://dx.doi.org/10.1007/s00018-021-03847-1DOI Listing
May 2021

Scorpion Stings and Antivenom Use in Arizona.

Am J Med 2021 Feb 22. Epub 2021 Feb 22.

Arizona Poison and Drug Information Center, University of Arizona, Tucson.

Background: Arizona's rugged desert landscape harbors many venomous animals, including a small nocturnal scorpion, Centruroides sculpturatus, whose venom can cause severe neuromotor disturbance. An effective antivenom is available at selected health care facilities in the state.

Methods: We analyzed 4398 calls of scorpion stings to the Arizona Poison and Drug Information Center (APDIC) in Tucson over a period of 3 years, from January 2017 to December 2019.

Results: We followed 1952 (44.4%) of the victims to resolution. We excluded 2253 callers with minimal effects of the sting and 193 victims with possible toxic effects who were lost to follow-up. The most common complaints among callers were pain at the sting site in 88.9% and local numbness in 62.2%. Detailed clinical information was obtained from 593 calls from a health care facility. Neuromotor signs consistent with C. sculpuratus envenomation included nystagmus in 163 (27.5%), hypersalivation in 91 (15.3%), and fasciculations in 88 (14.8%). Antivenom (Anascorp; Rare Disease Therapeutics, Inc., Franklin, Tenn) was administered to 145 patients. Most were children <5 years old (n = 76, or 54.4%); 27 (18.6%) were 5-9 years old and 42 (30.0%) were ≥10 years of age. About half, 79 of 145 (54.5%) victims who received antivenom, met the APDIC recommended use criteria.

Conclusions: Patients treated with antivenom exhibited a rapid resolution of symptoms without immediate or delayed hypersensitivity reactions. We recommend broadened availability of antivenom at sites where it is most needed.
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http://dx.doi.org/10.1016/j.amjmed.2021.01.025DOI Listing
February 2021

Ontogeny, species identity, and environment dominate microbiome dynamics in wild populations of kissing bugs (Triatominae).

Microbiome 2020 10 11;8(1):146. Epub 2020 Oct 11.

Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic.

Background: Kissing bugs (Triatominae) are blood-feeding insects best known as the vectors of Trypanosoma cruzi, the causative agent of Chagas' disease. Considering the high epidemiological relevance of these vectors, their biology and bacterial symbiosis remains surprisingly understudied. While previous investigations revealed generally low individual complexity but high among-individual variability of the triatomine microbiomes, any consistent microbiome determinants have not yet been identified across multiple Triatominae species.

Methods: To obtain a more comprehensive view of triatomine microbiomes, we investigated the host-microbiome relationship of five Triatoma species sampled from white-throated woodrat (Neotoma albigula) nests in multiple locations across the USA. We applied optimised 16S rRNA gene metabarcoding with a novel 18S rRNA gene blocking primer to a set of 170 T. cruzi-negative individuals across all six instars.

Results: Triatomine gut microbiome composition is strongly influenced by three principal factors: ontogeny, species identity, and the environment. The microbiomes are characterised by significant loss in bacterial diversity throughout ontogenetic development. First instars possess the highest bacterial diversity while adult microbiomes are routinely dominated by a single taxon. Primarily, the bacterial genus Dietzia dominates late-stage nymphs and adults of T. rubida, T. protracta, and T. lecticularia but is not present in the phylogenetically more distant T. gerstaeckeri and T. sanguisuga. Species-specific microbiome composition, particularly pronounced in early instars, is further modulated by locality-specific effects. In addition, pathogenic bacteria of the genus Bartonella, acquired from the vertebrate hosts, are an abundant component of Triatoma microbiomes.

Conclusion: Our study is the first to demonstrate deterministic patterns in microbiome composition among all life stages and multiple Triatoma species. We hypothesise that triatomine microbiome assemblages are produced by species- and life stage-dependent uptake of environmental bacteria and multiple indirect transmission strategies that promote bacterial transfer between individuals. Altogether, our study highlights the complexity of Triatominae symbiosis with bacteria and warrant further investigation to understand microbiome function in these important vectors. Video abstract.
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http://dx.doi.org/10.1186/s40168-020-00921-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7549230PMC
October 2020

Autochthonous Chagas Disease: How Are These Infections Happening?

Am J Med 2020 12 17;133(12):e683-e686. Epub 2020 Jul 17.

Department of Entomology, University of Arizona, Tucson.

Proven cases of vector-transmitted acute autochthonous Chagas disease in the United States are rare (<10 cases). Possible or probable cases of unknown duration determined by serology are uncommon as well (<100). In Latin America it is widely accepted that after feeding, the kissing bug defecates and Trypanosoma cruzi in the feces is rubbed into the bite punctum. This is an inefficient method of parasite transmission. The average infected individual in Latin America suffers more than 1000 bites, but more importantly, there are often thousands of kissing bugs in a household dropping feces on the inhabitants and living quarters. Today in Brazil the most common form of acute Chagas is secondary to oral ingestion of the parasite in food and drink. We present our experience with many hundreds of individuals bitten by kissing bugs and the possibility of oral ingestion occurring in the United States.
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http://dx.doi.org/10.1016/j.amjmed.2020.06.017DOI Listing
December 2020

The Reply.

Am J Med 2020 06;133(6):e322

University of Arizona School of Medicine, Tucson. Electronic address:

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http://dx.doi.org/10.1016/j.amjmed.2020.02.008DOI Listing
June 2020

Honeybee Stings in the Era of Killer Bees: Anaphylaxis and Toxic Envenomation.

Am J Med 2020 05 9;133(5):621-626. Epub 2019 Nov 9.

Department of Medicine, University of Arizona, Tucson, Arizona. Electronic address:

Background: Twenty-six years after the arrival of "killer bees" in Arizona, the entire state with the exception of high elevations in the north is populated with this bee variety and 11 people have died at the scene of massive bee attacks.

Methods: Because of the aggressive behavior of these bees we studied bee stings reported to the Arizona Poison and Drug Information Center. The center received 399 calls regarding 312 victims of bee stings from January 2017 to June 2019. Calls originated from private residences and emergency centers.

Results: Stings occurred at victims' home residences in 272 (84.7%) of cases and 24 (7.5%) in public areas; 251 people suffered 1 sting; 42 individuals, 2-10 stings, 4 had 11-49 stings, and 13 individuals had >50 stings (so-called massive stinging). Three individuals were admitted to intensive care units (ICU) and one 35-year-old man died of anaphylaxis after 1 sting; moderate clinical effects occurred in 32 individuals including 6 admitted to the hospital but not in the intensive care unit. Anaphylaxis occurred in 30 (9.6%) of individuals, 16 receiving 1 sting. Toxic effects, tachycardia, elevated creatinine, or rhabdomyolysis occurred in 13 (4.2%) individuals.

Conclusions: In the past, individuals stung more than 50 times were beekeepers working with European honeybees, whereas, in the current era, single as well as massive stings are the result of feral "killer bees." This change in epidemiology requires a new approach to sting victims: those with massive stinging should be evaluated and observed for anaphylaxis and serial laboratory values obtained for days to detect the toxic effects of envenomation.
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http://dx.doi.org/10.1016/j.amjmed.2019.10.028DOI Listing
May 2020

Pain and Lethality Induced by Insect Stings: An Exploratory and Correlational Study.

Authors:
Justin O Schmidt

Toxins (Basel) 2019 07 21;11(7). Epub 2019 Jul 21.

Southwestern Biological Institute, 1961 W. Brichta Dr., Tucson, AZ 85745, USA.

Pain is a natural bioassay for detecting and quantifying biological activities of venoms. The painfulness of stings delivered by ants, wasps, and bees can be easily measured in the field or lab using the stinging insect pain scale that rates the pain intensity from 1 to 4, with 1 being minor pain, and 4 being extreme, debilitating, excruciating pain. The painfulness of stings of 96 species of stinging insects and the lethalities of the venoms of 90 species was determined and utilized for pinpointing future directions for investigating venoms having pharmaceutically active principles that could benefit humanity. The findings suggest several under- or unexplored insect venoms worthy of future investigations, including: those that have exceedingly painful venoms, yet with extremely low lethality-tarantula hawk wasps () and velvet ants (Mutillidae); those that have extremely lethal venoms, yet induce very little pain-the ants, and ; and those that have venomous stings and are both painful and lethal-the ants , , , , and the social wasps , , and . Taken together, and separately, sting pain and venom lethality point to promising directions for mining of pharmaceutically active components derived from insect venoms.
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http://dx.doi.org/10.3390/toxins11070427DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6669698PMC
July 2019

Kissing Bugs Harboring Trypanosoma cruzi, Frequently Bite Residents of the US Southwest But Do Not Cause Chagas Disease.

Am J Med 2020 01 8;133(1):108-114.e13. Epub 2019 Jul 8.

Department of Medicine, University of Arizona, Tucson. Electronic address:

Background: Kissing bugs are common household pests in the Desert Southwest of the United States. These hematophagous bugs enter homes and suck blood from resident humans and pets. They are vectors of Trypanosoma cruzi, an enzootic parasite in small mammals and the cause of Chagas disease in humans. Autochthonous cases of Chagas disease are rare in the United States despite the presence of the vector and parasite. Environmental and biological factors accounting for this phenomenon need studying.

Methods: Homeowners in Bisbee and Tucson, Arizona captured kissing bugs inside homes during 2017-2018. Bugs were tested for presence of T. cruzi by polymerase chain reaction. Residents bitten by kissing bugs were tested for Chagas disease by serology. We evaluated invaded homes in the 2 cities.

Results: Three species of kissing bugs (n = 521) were collected in or near homes. Triatoma rubida was the most common triatomine in Tucson; T. recurva in Bisbee. T. protracta was uncommon. Seventeen percent of bugs captured in Bisbee and 51.1% in Tucson harbored T. cruzi. Bite victims (n = 105) recalled more than 2200 bites. Reactions to bites were common, including 32 episodes of anaphylaxis in 11 people (10.5%). Tests for Chagas disease (n = 116) were negative. Median age of houses was 91 years in Bisbee and 7 years in Tucson. Bisbee houses had pier and beam foundations. Tucson houses were built on concrete slabs.

Conclusions: Kissing bugs harboring T. cruzi readily entered new and old homes. Bites of humans caused severe, life-threatening reactions. There was no serological evidence of Chagas disease among those bitten.
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http://dx.doi.org/10.1016/j.amjmed.2019.06.016DOI Listing
January 2020

Rapid detection of human blood in triatomines (kissing bugs) utilizing a lateral flow immunochromatographic assay - A pilot study.

Mem Inst Oswaldo Cruz 2019 30;114:e190047. Epub 2019 May 30.

University of Arizona College of Medicine, Department of Medicine, Division of Infectious Diseases, Tucson, AZ, United States of America.

Objectives: We tested a rapid and specific immunochromatographic assay (that detects human blood in forensic samples) to determine if human blood was present in triatomines and their fecal excreta.

Methods: We fed Triatoma rubida human blood (positive control) or mouse blood (negative control) and performed the assay on the abdominal contents and fecal excreta. Triatomine field specimens collected in and around human habitations and excreta were also tested.

Findings: The assay was positive in triatomines fed human blood (N = 5/5) and fecal excreta from bugs known to have ingested human blood (N = 5/5). Bugs feeding on mice (N = 15/15) and their fecal excreta (N = 8/8) were negative for human blood. Human blood was detected in 47% (N = 23/49) triatomines, representing six different species, collected in the field.

Main Conclusions: The pilot study shows that this rapid and specific test may have applications in triatomine research. Further study is needed to determine the sensitivity of this assay compared to other well-established techniques, such as DNA- and proteomics-based methodologies and the assay's application in the field.
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http://dx.doi.org/10.1590/0074-02760190047DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6543902PMC
August 2019

Unconscious Woman in Shock and Covered with Ants Pulled from an Abandoned Automobile.

Am J Med 2019 10 3;132(10):1239-1241. Epub 2019 Apr 3.

Department of Medicine, College of Medicine, University of Arizona, Tucson. Electronic address:

Background: A middle-aged woman was taken from an abandoned automobile unconscious and covered with ants in Tucson, Arizona. When hospitalized in July 2018, she had an extensive papular-pustular skin eruption on her abdomen and thigh and disseminated intravascular coagulation. She was stung innumerable times by native golden fire ants (Solenopsis aurea) while sleeping in the vehicle. The large amount of venom injected by stings into this individual may have triggered dissemnated intravascualar coagulation because the venom contains powerful hemolytic factors.

Methods: The patient history is presented and ants were captured and identified.

Results: Clinical findings of fire ant stings are presented and the importance of recognizing the distinctive skin lesions that occur is emphasized. Stings of the red imported fire ant, Solenopsis invicta, and the black imported fire ant, Solenopsis richteri, cause skin lesions recognized by physicians and victims alike in the southern and southeastern United States. Native fire ant stings are documented much less often. However, there is significant cross-reactivity among the venoms of Solenopsis species.

Conclusion: It is important for clinicians to recognize the characteristic skin lesions of fire ant envenomation as fire ant populations are expanding and they sting millions of people each year.
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http://dx.doi.org/10.1016/j.amjmed.2019.02.053DOI Listing
October 2019

Second-Best Is Better Than Nothing: Cockroaches as a Viable Food Source for the Kissing Bug Triatoma recurva (Hemiptera: Reduviidae).

J Med Entomol 2019 04;56(3):651-655

Division of Infectious Diseases, Department of Medicine, University of Arizona, Tucson.

Kissing bugs in the genus Triatoma are obligate blood feeders that feed mainly on vertebrate blood and have lost the predatory lifestyle found in other reduviid bugs. They occasionally also feed on the hemolymph of arthropods, especially during the first and second instar stages. The largest kissing bug species in the United States, Triatoma recurva (Stål) (Hemiptera: Reduviidae), is poorly known and was chosen to investigate its ability to feed and develop on a diet of cockroach hemolymph. Molting from first instar individuals to second instars readily occurred at approximately the same rate reported for the species feeding on mammalian blood. Subsequent instars also fed on and survived on cockroach hemolymph with some individuals maturing to adults. In the larger instars, development time and survival rates were reduced relative to the results reported in the literature for mammalian-blood-fed individuals. Two other species of kissing bugs, Triatoma protracta (Uhler) and T. rubida (Uhler) failed to survive on cockroach hemolymph with most individuals failing to molt from the first instar stage. Although T. recurva does not thrive on a diet limited to hemolymph of cockroaches, it appears to be an unusual species in which cockroaches might be a primary source of nutrition for smaller individuals and are a viable exclusive source of nutrition for all immatures. At a minimum during times of limited availability of vertebrate blood sources, the presence of cockroaches enhances survival opportunities. Efforts to control populations of this kissing bug species likely will be improved with additional control of cockroach populations in the environment.
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http://dx.doi.org/10.1093/jme/tjy233DOI Listing
April 2019

Protein mass spectrometry extends temporal blood meal detection over polymerase chain reaction in mouse-fed Chagas disease vectors.

Mem Inst Oswaldo Cruz 2018 Aug 27;113(10):e180160. Epub 2018 Aug 27.

University of Vermont, Department of Biology, Burlington, VT, United States of America.

Background: Chagas disease is highly prevalent in Latin America, and vector control is the most effective control strategy to date. We have previously shown that liquid chromatography tandem mass spectrometry (LC-MS/MS) is a valuable tool for identifying triatomine vector blood meals.

Objectives: The purpose of this study was to determine blood meal detection ability as a function of method [polymerase chain reaction (PCR) vs. LC-MS/MS], time since feeding, and the effect of molting in mouse-fed triatomine insect vectors targeting hemoglobin and albumin proteins with LC-MS/MS and short interspersed nuclear elements (SINE)-based PCR.

Methods: We experimentally fed Triatoma protracta on mice and used LC-MS/MS to detect hemoglobin and albumin peptides over time post-feeding and post-molting (≤ 12 weeks). We compared LC-MS/MS results with those of a standard PCR method based on SINEs.

Findings: Hemoglobin-based LC-MS/MS detected blood meals most robustly at all time points post-feeding. Post-molting, no blood meals were detected with PCR, whereas LC-MS/MS detected mouse hemoglobin and albumin up to 12 weeks.

Main Conclusions : In our study, the hemoglobin signature in the insect abdomen lasted longer than that of albumin and DNA. LC-MS/MS using hemoglobin shows promise for identifying triatomine blood meals over long temporal scales and even post-molting. Clarifying the frequency of blood-feeding on different hosts can foster our understanding of vector behavior and may help devise sounder disease-control strategies, including Ecohealth (community based ecosystem management) approaches.
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http://dx.doi.org/10.1590/0074-02760180160DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6167943PMC
August 2018

Microbiomes of North American Triatominae: The Grounds for Chagas Disease Epidemiology.

Front Microbiol 2018 13;9:1167. Epub 2018 Jun 13.

Faculty of Science, University of South Bohemia, Ceske Budejovice, Czechia.

Insect microbiomes influence many fundamental host traits, including functions of practical significance such as their capacity as vectors to transmit parasites and pathogens. The knowledge on the diversity and development of the gut microbiomes in various blood feeding insects is thus crucial not only for theoretical purposes, but also for the development of better disease control strategies. In Triatominae (Heteroptera: Reduviidae), the blood feeding vectors of Chagas disease in South America and parts of North America, the investigation of the microbiomes is in its infancy. The few studies done on microbiomes of South American Triatominae species indicate a relatively low taxonomic diversity and a high host specificity. We designed a comparative survey to serve several purposes: (I) to obtain a better insight into the overall microbiome diversity in different species, (II) to check the long term stability of the interspecific differences, (III) to describe the ontogenetic changes of the microbiome, and (IV) to determine the potential correlation between microbiome composition and presence of , the causative agent of Chagas disease. Using 16S amplicons of two abundant species from the southern US, and four laboratory reared colonies, we showed that the microbiome composition is determined by host species, rather than locality or environment. The OTUs (Operational Taxonomic Units) determination confirms a low microbiome diversity, with 12-17 main OTUs detected in wild populations of and . Among the dominant bacterial taxa are and but also the symbiotic bacterium , previously believed to only live intracellularly. The possibility of ontogenetic microbiome changes was evaluated in all six developmental stages and feces of the laboratory reared model . We detected considerable changes along the host's ontogeny, including clear trends in the abundance variation of the three dominant bacteria, namely , and . Finally, we screened the samples for the presence of . Comparing the parasite presence with the microbiome composition, we assessed the possible significance of the latter in the epidemiology of the disease. Particularly, we found a trend toward more diverse microbiomes in positive specimens.
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http://dx.doi.org/10.3389/fmicb.2018.01167DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6008411PMC
June 2018

Clinical consequences of toxic envenomations by Hymenoptera.

Authors:
Justin O Schmidt

Toxicon 2018 Aug 19;150:96-104. Epub 2018 May 19.

Southwestern Biological Institute, 1961 W. Brichta Drive, Tucson, AZ 85745, USA. Electronic address:

Many familiar Hymenoptera are brightly colored and can sting painfully-thus, their threat and clinical importance may be exaggerated. Most stinging insects only sting to defend themselves or their colonies from predators. The clinical nature of Hymenoptera envenomations contrasts that of other venomous animals, including other arthropods, primarily because allergic reaction, not direct intoxication, is the usual main concern. This review focuses mainly on the clinical features of direct toxicity to Hymenoptera envenomations, which can induce a high incidence of acute renal failure, liver failure, multiple organ failures, and death. Toxic mass envenomations by honeybees usually entail many hundreds or more stings per victim. In contrast to honeybee toxic envenomations, hornet sting envenomations can be clinically threatening with only 20-200 stings needed to cause kidney and other organ failures. Many lethal envenomations by honeybees occur in rural areas in the New World and Africa and are not recorded or documented. In contrast, deaths by hornets occur mainly to Asia. The most frequent and important envenomating taxa are honeybees, hornets, yellowjacket wasps, paper wasps, fire ants, and jack jumper ants. Occasional envenomating taxa include bumblebees, bullet ants, harvester ants, solitary wasps, solitary bees, and various ants of lesser clinical importance. Envenomations by Hymenoptera usually can be avoided if one considers that bees, wasps and ants "view" us as potential threats or predators, and that with information about the biology of stinging Hymenoptera, humans can minimize adverse incidents.
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http://dx.doi.org/10.1016/j.toxicon.2018.05.013DOI Listing
August 2018

A reexamination of poneratoxin from the venom of the bullet ant Paraponera clavata.

Peptides 2017 Dec 3;98:51-62. Epub 2016 Jun 3.

Department of Neurology, University of Louisville, Louisville, KY, United States.

In 1991, Piek et al. [45] described a voltage-gated sodium channel (VGSC) modifier from "bullet ant" (Paraponera clavata) venom they called poneratoxin (PoTx). Using UV chromatography and Edman degradation they showed two "identical peptides" of 25 residues. We reinvestigated PoTx using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-TMS). De novo sequencing showed the two peptides were actually structurally different peptides: the originally described PoTx and a glycyl pro-peptide (glycyl-PoTx) that lacks C-terminus amidation. We examined P. clavata venom from different geographical locations and discovered two additional PoTx analogs: an A23E substitution analog and a D22N; A23V substitutions analog. We tested PoTx and these three natural analogs on the mammalian sensory voltage-gated sodium channel, Na1.7, using whole cell voltage-clamp. PoTx and each analog induced slowly activating currents in response to small depolarizing steps and sustained currents due to blockade of channel inactivation, similar to that described previously in skeletal muscle [19]. Glycyl-PoTx had the same potency and efficacy as PoTx. A23E PoTx, with a decrease in both C-terminal net positive charge and hydrophobicity, had an eight-fold reduction in potency compared to PoTx. In contrast, the D22N; A23V PoTx, with an increase in both C-terminal net positive charge and hydrophobicity, had a nearly five-fold increase in potency compared to PoTx. We found that changes in PoTx C-terminus caused a significant change in PoTx potency.
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http://dx.doi.org/10.1016/j.peptides.2016.05.012DOI Listing
December 2017

Kissing Bug (Triatoma spp.) Intrusion into Homes: Troublesome Bites and Domiciliation.

Environ Health Insights 2016 23;10:45-9. Epub 2016 Mar 23.

Southwest Biological Institute, Tucson, AZ, USA.

Kissing bugs (Triatoma spp.) frequently enter homes and bite human and pet occupants. Bites may lead to severe allergic reactions and, in some cases, death. Kissing bugs are also vectors of Trypanosoma cruzi, the cause of Chagas disease. In general, modern houses in the United States are not conducive to domiciliation of kissing bugs (bugs living out their entire life within the home with the presence of eggs, nymphs, adults, and exuviae). Construction features such as concrete foundations, solid walls and ceilings, window screens, tight thresholds for doors and windows, and other measures impede bug entry into homes, and air conditioning reduces the need for open doors and windows. Where Chagas disease is endemic in Mexico and Central and South America, homes often have thatch roofs, adobe walls, and open doors and windows. We investigated numerous instances of kissing bug intrusions into homes in Southern Arizona, California, and Louisiana and documented the reactions to kissing bug bites. Our work confirms the importance of modern home construction in limiting kissing bug intrusions. Older homes, especially those lacking modern screening, caulking, and weather stripping to reduce air leakage, may be subject to kissing bug intrusions and domiciliation. We describe a community in Southern Arizona where domiciliation of homes by Triatoma recurva is common. We also provide recent data regarding kissing bug bites and allergic reactions to the bites.
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http://dx.doi.org/10.4137/EHI.S32834DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4807888PMC
April 2016

Kissing bugs in the United States: risk for vector-borne disease in humans.

Environ Health Insights 2014 10;8(Suppl 2):49-59. Epub 2014 Dec 10.

Southwestern Biological Institute, Tucson, USA.

Eleven species of kissing bugs are found in the United States. Their home ranges may be expanding northward, perhaps as a consequence of climate change. At least eight of the species, perhaps all, are reported to harbor Trypanosoma cruzi, the parasite that causes Chagas disease. Because humans are encroaching on kissing bug habitat, there is concern for vector-transmitted Chagas disease in the United States. To date, documented autochthonous cases of Chagas in humans in the United States are rare. Kissing bugs are capable of adapting to new habitats such as human domiciles; however, they do not colonize homes in the United States as in Central and South America. We review the biology, behavior, and medical importance of kissing bugs and the risk they pose for transmission of Chagas disease in the United States. Where possible, descriptions of US species are compared to the epidemiologically important Latin American species.
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http://dx.doi.org/10.4137/EHI.S16003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4264683PMC
January 2015

Evolutionary responses of solitary and social Hymenoptera to predation by primates and overwhelmingly powerful vertebrate predators.

Authors:
Justin O Schmidt

J Hum Evol 2014 Jun 22;71:12-9. Epub 2014 Mar 22.

Southwestern Biological Institute, 1961 W. Brichta Dr., Tucson, AZ 85745, USA. Electronic address:

Insects provide an important part of the diet of primates, including hominins. Investigations of insectivory in primates has focused primarily on the value of insects in the diet, and on the means of obtaining the insects, with little attention devoted to the predator-prey relationship itself and less to evolutionary aspects of insect defense against predatory vertebrates, including primates. Data indicate that, far from being a passive half of the relationship, insects in general, and stinging Hymenoptera in particular, are active participants that have greatly influenced the relationship. Predators have been a strong component of the selection pressure in the evolution of painful and toxic bee, wasp, and ant stings and these insects, in turn, have influenced hunting behavior and learning in at least higher primates. The special example of honey bees and humans is highlighted. Both humans and the bees have benefitted from a relationship that represents an unprecedented example of a predator-prey interaction evolving recently into facultative mutualism.
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http://dx.doi.org/10.1016/j.jhevol.2013.07.018DOI Listing
June 2014

Free-roaming kissing bugs, vectors of Chagas disease, feed often on humans in the Southwest.

Am J Med 2014 May 4;127(5):421-6. Epub 2014 Jan 4.

Department of Biology, University of Vermont, Burlington.

Background: Kissing bugs, vectors of Trypanosoma cruzi, the parasite that causes Chagas disease, are common in the desert Southwest. After a dispersal flight in summer, adult kissing bugs occasionally gain access to houses where they remain feeding on humans and pets. How often wild, free-roaming kissing bugs feed on humans outside their homes has not been studied. This is important because contact of kissing bugs with humans is one means of gauging the risk for acquisition of Chagas disease.

Methods: We captured kissing bugs in a zoological park near Tucson, Arizona, where many potential vertebrate hosts are on display, as well as being visited by more than 300,000 humans annually. Cloacal contents of the bugs were investigated for sources of blood meals and infection with T. cruzi.

Results: Eight of 134 captured bugs were randomly selected and investigated. All 8 (100%) had human blood in their cloacae, and 7 of 8 (88%) had fed on various vertebrates on display or feral in the park. Three bugs (38%) were infected with T. cruzi. Three specimens of the largest species of kissing bug in the United States (Triatoma recurva) were captured in a cave and walking on a road; 2 of 3 (67%) had fed on humans. No T. recurva harbored T. cruzi.

Conclusions: This study establishes that free-roaming kissing bugs, given the opportunity, frequently feed on humans outside the confines of their homes in the desert Southwest and that some harbored T. cruzi. This could represent a hitherto unrecognized potential for transmission of Chagas disease in the United States.
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http://dx.doi.org/10.1016/j.amjmed.2013.12.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4096837PMC
May 2014

Vector blood meals and Chagas disease transmission potential, United States.

Emerg Infect Dis 2012 Apr;18(4):646-9

University of Vermont, Burlington, Vermont 05405, USA.

A high proportion of triatomine insects, vectors for Trypanosoma cruzi trypanosomes, collected in Arizona and California and examined using a novel assay had fed on humans. Other triatomine insects were positive for T. cruzi parasite infection, which indicates that the potential exists for vector transmission of Chagas disease in the United States.
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http://dx.doi.org/10.3201/eid1804.111396DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3309679PMC
April 2012

Kissing bugs. The vectors of Chagas.

Adv Parasitol 2011 ;75:169-92

Department of Biology, University of Vermont, Burlington, VT, USA.

A complete picture of Chagas disease requires an appreciation of the many species of kissing bugs and their role in transmitting this disease to humans and other mammals. This chapter provides an overview of the taxonomy of the major species of kissing bugs and their evolution. Knowledge of systematics and biological kinship of these insects may contribute to novel and useful measures to control the bugs. The biology of kissing bugs, their life cycle, method of feeding and other behaviours contributing to the transmission of Trypanosoma cruzi are explained. We close with a discussion of vector control measures and the allergic complications of kissing bug bites, a feature of particular importance in the United States.
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http://dx.doi.org/10.1016/B978-0-12-385863-4.00008-3DOI Listing
December 2011

"Kissing bugs": potential disease vectors and cause of anaphylaxis.

Clin Infect Dis 2010 Jun;50(12):1629-34

Department of Entomology, University of California, Riverside, CA, USA.

Physicians in the United States should familiarize themselves with "kissing bugs" endemic to their area of practice and appreciate the medical implications of their bites. Bite victims often seek advice from physicians about allergic reactions as well as the risk of contracting Chagas disease. Physicians are generally knowledgeable about the role of kissing bugs in the transmission of Trypanosoma cruzi in Latin America. However, they may be unaware of (1) severe allergic reactions to kissing bug salivary antigens, (2) the widespread occurrence of T. cruzi amongst vertebrate hosts of kissing bugs, and (3) the incidence of T. cruzi among kissing bugs (T. cruzi may infect >50% of sampled bugs). Despite the potential for Chagas disease transmission, the major concern regarding kissing bugs in the United States is anaphylactic reactions to their bites resulting in frequent emergency department visits, especially in areas of endemicity in the Southwest.
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http://dx.doi.org/10.1086/652769DOI Listing
June 2010

What's eating you? Native and imported fire ants.

Cutis 2009 Jan;83(1):17-20

Department of Entomology, University of California, Riverside, USA.

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January 2009

Semantics of toxinology.

Toxicon 2006 Jul 28;48(1):1-3. Epub 2006 Apr 28.

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http://dx.doi.org/10.1016/j.toxicon.2006.04.004DOI Listing
July 2006

Adverse reactions to ants other than imported fire ants.

Ann Allergy Asthma Immunol 2005 Nov;95(5):418-25

Department of Entomology, University of California, Riverside 92521, USA.

Objective: To identify ants other than Solenopsis invicta and Solenopsis richteri reported to cause adverse reactions in humans.

Data Sources: We conducted a literature review to identify reports of medical reactions to ants other than S. invicta and S. richteri. Our review of medical and entomological literature on stinging ants was generated from MEDLINE and FORMIS, respectively, using the key words stinging ants and ant stings. The search was limited to articles in English published from 1966 to 2004 on MEDLINE and all years on FORMIS. We also present 3 new case reports of severe reactions to stings by 2 different species of ants, Pseudomyrmex ejectus and Hypoponera punctatissima.

Study Selection: Articles that concerned anaphylactic (IgE-mediated) or anaphylactic-like (resembling anaphylaxis but mechanism unknown) immediate reactions to ant stings or bites were included in this review.

Results: Taken together, our data demonstrate that S. invicta and S. richteri are not alone in their capability to cause serious allergic or adverse reactions. A diverse array of ant species belonging to 6 different subfamilies (Formicinae, Myrmeciinae, Ponerinae, Ectatomminae, Myrmicinae, and Pseudomyrmecinae) and 10 genera (Solenopsis, Formica, Myrmecia, Tetramorium, Pogonomyrmex, Pachycondyla, Odontomachus, Rhytidoponera, Pseudomyrmex, and Hypoponera) have now been shown to have this capability.

Conclusion: Awareness that species other than imported fire ants may cause severe reactions should lead to more rapid evaluation and treatment and further investigation of the medical entomology of these ants.
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http://dx.doi.org/10.1016/S1081-1206(10)61165-9DOI Listing
November 2005

Modulation of nicotinic acetylcholine and N-methyl-d-aspartate receptors by some Hymenopteran venoms.

Toxicon 2005 Sep;46(3):282-90

Department of Zoology, Suez Canal University, Ismailia, Egypt; School of Biology, University of Nottingham, University Park, Nottingham NG7 2RD, UK.

The effect of 19 venoms from solitary wasps, solitary bees, social wasps and ants were investigated for their effects on nicotinic acetylcholine receptors (nAChR) and ionotropic glutamate receptors (IGRs) of both the N-methyl-d-aspartate (NMDAR) and non-NMDAR type. Whole-cell patch clamp of human muscle TE671 cells was used to study nAChR, and of rat cortical and cerebellar granule cells for IGRs. Solitary wasp venoms caused significant voltage-dependent antagonism of nAChR responses to 10 microM ACh and NMDAR responses to 100 microM NMDA (+10 microM glycine) when co-applied at 1 microg/ml with the agonists. At positive holding potentials (V(H)) potentiation of these receptors was observed with some venoms. Solitary bee venoms only affected nAChR by causing either voltage-independent antagonism or potentiation of their responses to 10 microM ACh. Of four social wasp venoms, one acted on nAChR by potentiating responses to 10 ACh, while another generated an ACh-like response when applied alone. They had no effect on IGRs. Of the two ant venoms, one caused voltage-independent inhibition of nAChR. Neither affected IGRs. The data indicate the presence of nAChR agonists and antagonists and NMDAR antagonists in Hymenopteran venoms and warrant further investigation to separate and identify these venom components.
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http://dx.doi.org/10.1016/j.toxicon.2005.04.015DOI Listing
September 2005

Olfactory stimulation of Africanized honey bee (Hymenoptera: Apidae) attacks by insect repellents.

J Med Entomol 2003 May;40(3):275-8

Carl Hayden Bee Research Center, USDA-ARS, 2000 E. Allen Road, Tucson, AZ 85719, USA.

Three common insect repellents (N,N-diethyl-m-toluamide [DEET], Pyranha, and Repel X) were tested to determine whether they affected Africanized honey bee attack behavior. Eight Africanized honey bee (Apis mellifera L.) colonies were exposed in an alternating series to the test repellents or blank controls delivered in a stream of air directed toward the colony entrances. The response generated by the repellents and the controls was measured as the number of attacking honey bees recorded with an electronic temper tester. Neither a citronella-based repellent (Pyranha) nor DEET had any effect on colony behavior; however, Repel X consistently caused a greater attack response after exposure.
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http://dx.doi.org/10.1603/0022-2585-40.3.275DOI Listing
May 2003

The effect of octopamine on behavioral responses of free-foraging bumblebees to a change in food source profitability.

Naturwissenschaften 2003 Apr 25;90(4):185-8. Epub 2003 Mar 25.

Carl Hayden Bee Research Center, USDA-ARS, 2000 E. Allen Rd., Tucson, AZ 85719, USA.

The invertebrate neuromodulator octopamine is known to be involved in bees' associative learning, enhancing the responsiveness of a bee to a conditioned stimulus. In this study, we tested the effect of octopamine on the choice behavior of free-flying bumblebees using a two-phase experiment in an array of artificial flowers. During the first phase of the experiment, the bee was allowed to collect octopamine-laden sugar water from two types of equally rewarding flowers (yellow versus blue). In the second phase, one type of flower was set to be unrewarding. The behavior of the bee (proportion of visits to the unrewarding flowers) over the two phases was fitted to a sigmoid regression model. Our results show that octopamine had no significant effect on the bees' equilibrium choice or on the overall rate of the behavioral change in response to the change in reward. Rather, octopamine significantly affected the time interval between the change in reward status and the initiation of behavioral change in the bee.
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http://dx.doi.org/10.1007/s00114-003-0412-9DOI Listing
April 2003

Floral biology of the saguaro (Cereus giganteus) : I. Pollen harvest by Apis mellifera.

Oecologia 1986 Jul;69(4):491-498

Agricultural Research Service, Carl Hayden Bee Research Center, U.S. Department of Agriculture, 2000 E. Allen Road, 85719, Tucson, AZ, USA.

A saguaro cactus (Cereus giganteus) produces an average of 295 flowers per season, each of which produces 286 mg fresh weight of pollen and 543 mg of nectar containing 24% sugar. At 7600 pollen grains/mg pollen, the yearly output per saguaro plant is 6.4×10 grains. Based on the measured saguaro density of 6.56 plants/ha, 553 g/ha of pollen is produced yearly. The enormous variation among individual plants in terms of flower numbers and floral bloom patterns is documented.Honey bees (Apis mellifera L.), the main collectors of saguaro pollen, collect an average of 12.2 mg pollen per foraging trip and can thus harvest 23.5 pollen loads from one flower. An average honey bee colony collects 290 g of saguaro pollen over the season, which is 24.4% of their total intake. Individual colonies exhibit wide variation in pollen collecting activities with some closely tracking the pollen resource and others almost totally ignoring it. The average for seven colonies indicates that even though variation is great the overall trend is toward closely tracking and exploiting the saguaro pollen resource. Based on the pollen productivity of saguaro and a hypothetical 90% pollen harvesting efficiency of bees, the pollen harvest potential of the saguaro environment is 1.72 colony equivalents of pollen/ha and 0.5/ha for saguaro alone. This is the first quantitative reporting of the total pollen productivity and pollen resource utilization for any plant and an opportunistic pollinator.
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http://dx.doi.org/10.1007/BF00410353DOI Listing
July 1986