Reduce Air Leakage Research Articles

Air leakage mechanism and hole sealing technology in directional long-drilled perimeter rock-borehole composite fissures: for gas enrichment in varying coal-seam thickness change areas

The issue of gas enrichment in the tectonic zone of coal seams, which poses significant threats to coal mine safety and leads to gas disasters, is primarily addressed through borehole extraction. The quality of this extraction is notably influenced by air leakage and sealing technologies used during drilling. To tackle the problem of gas leakage in directional long boreholes within the floor, a composite fissure leakage model for the surrounding rock and borehole is developed. This model inverts the characteristics of coal seam thickness variations and abnormal gas enrichment through heterogeneous geostatistical modeling. It enables the quantitative characterization of the air leakage mechanism in directional long boreholes of the bottom plate and proposes an effective sealing process. Due to damage and disturbance, fissures and irregular plastic zones form around the excavated roadway, which are major contributors to air leakage. Over time, the air content in the coal and rock seams gradually increases while the gas content and concentration decrease continuously. Compared to the polyurethane "two plugs and one injection" sealing process, the multi-stage grouting and sealing process provides a more stable gas extraction concentration and flow rate in the sealed drill holes. This process effectively seals the fissure zones of the roadway, reduces air leakage from the boreholes, and improves gas extraction concentration.

Study on Spontaneous Combustion Risk Areas in Narrow Coal Pillar-Utilized Deep Mining and Double-Pipe Liquid CO2 Injection Technology

ABSTRACT Coal spontaneous combustion (CSC) in goafs, one of the most serious disasters in coal mines, not only wastes resources and destroys the ecological environment, but also causes casualties. As global underground mining gradually shifts to the deep, this problem becomes increasingly prominent. Deep mining is operated in a complex mechanical environment characterized with high stress, high permeability, high temperature, and strong mining disturbance. To avoid stress concentration areas, narrow coal pillars are often utilized in roadway excavation along the goaf. However, narrow coal pillars are likely to fracture and lose stability during the mining process. Consequently, goaf areas of two adjacent working faces might connect, which promotes the CSC risk in the goaf. Most of the current researches are focused on CSC risk areas under shallow mining conditions and the CSC-gas coupling disasters, yet research on CSC risk areas in the goaf triggered by narrow coal pillars under deep mining conditions is rarely reported. Moreover, there is a lack of relevant means to prevent and extinguish fires. This study takes the narrow coal pillar-utilized 130,205 working face in Yangchangwan Coal Mine as the research object. First, the development of coal pillar fractures was simulated by adopting the discrete element method of PFC. Besides, on-site monitoring and FLUENT numerical simulation were conducted to identify CSC risk areas in the goaf of the narrow coal pillar-utilized working face. Finally, a double-pipe liquid CO2 injection technology was proposed for fire prevention and extinguishing. The following beneficial results were obtained. Affected by high stress in deep mining, the coal pillar collapses, which expands the range of the oxidation zone on the return side. Meanwhile, the adjacent goaf is also exposed to CSC risk. Double-pipe liquid CO2 injection can effectively reduce air leakage near the working face and suppress spontaneous combustion of residual coal by inerting the goaf. This study can provide guidance and reference for fire prevention and extinguishing in goafs under the condition of narrow coal pillar-utilized deep mining.

Study on the fit of nonwoven face masks on different face shapes

In the midst of the global COVID-19 pandemic, airborne infectious diseases, including contagious tuberculosis and illnesses transmitted through airborne droplets, such as influenza, SARS, and avian influenza, have emerged as some of the most severe pandemics in human history. Face masks have become an essential everyday item, despite their previous use primarily for the sick. Current mask designs come in various sizes; however, they may not be suitable for all face shapes, particularly for individuals with smaller or frequently moving facial features. Therefore, there is a need for research, especially focusing on women and individuals with smaller faces, to enhance the effectiveness of face masks in providing adequate protection. Accordingly, this study examined the current typical mask design ‘normal mask’ and four proposed mask designs for five face shapes (round, diamond, oval, square, or oblong) by using a quantitative fit test, as suggested in ISO 16975-3 and OSHA 29 CFR1910.134, to determine the masks’ fit factor (FF). The FF of the normal mask was 80% on round faces, 66% on diamond faces, but only 41% on square and oblong faces. The FaceMe artificial intelligence program was used to modify the face mask design in accordance with each face shape, and the level of air leakage was evaluated. The results showed that modifying the mask edges could reduce air leakage, especially during movements. For square faces, the leakage level was reduced from 63% (normal mask) to 38% (line mask). For oblong faces, the normal mask had a leakage level of 63%, whereas wave masks reduced leaking to 34%, resulting in a reduction of almost 30%. Mask fit could also be improved by adjusting earloop tightness.

Spontaneous combustion of coal in regenerated roof and its prevention technology

The dangerous zone of spontaneous combustion of coal in regenerated roof cannot be directly identified and the air leakage law is not clear, which makes it difficult to take effective control measures. Aiming at these problems, taking the 5304 working face of Zhoujing coal mine as the research object, the law of air leakage and the law of oxygen concentration change were studied and the dangerous zone of coal spontaneous combustion in the regenerated roof was delineated through experimental test and numerical simulation. The law of temperature rose in the dangerous zone was further analyzed. The hidden danger of spontaneous combustion was eliminated by using composite spraying materials and water injection. The results showed that when the temperature rose to 80℃, the coal sample of 5304 working face started to oxidize rapidly. The air leakage velocity and oxygen concentration of were directly affected by the ventilation rate in the regenerated roof. By superimposing the oxidation zone of air leakage velocity and the oxidation zone of oxygen concentration, the dangerous zone of coal spontaneous combustion was delineated and it was known that reducing air leakage can effectively eliminate the dangerous zone of coal spontaneous combustion. Composite spraying materials were used for the wall of the return airway and water was injected into the dangerous zone of coal spontaneous combustion, the roadway surface temperature and backwater temperature were reduced to 28.5℃ and 30.3℃ respectively. The oxygen concentration was reduced to 3.8–6.2%.

Reduced Air Leakage During Non-Invasive Ventilation Using a Simple Anesthetic Mask With 3D-Printed Adaptor in an Anthropometric Based Pediatric Head-Lung Model.

Non-invasive ventilation (NIV) is increasingly used in the support of acute respiratory failure in critically ill children admitted to the pediatric intensive care unit (PICU). One of the major challenges in pediatric NIV is finding an optimal fitting mask that limits air leakage, in particular for young children and those with specific facial features. Here, we describe the development of a pediatric head–lung model, based on 3D anthropometric data, to simulate pediatric NIV in a 1-year-old child, which can serve as a tool to investigate the effectiveness of NIV masks. Using this model, the primary aim of this study was to determine the extent of air leakage during NIV with our recently described simple anesthetic mask with a 3D-printed quick-release adaptor, as compared with a commercially available pediatric NIV mask. The simple anesthetic mask provided a better seal resulting in lower air leakage at various positive pressure levels as compared with the commercial mask. These data further support the use of the simple anesthetic mask as a reasonable alternative during pediatric NIV in the acute setting. Moreover, the pediatric head–lung model provides a promising tool to study the applicability and effectiveness of customized pediatric NIV masks in the future.

Pleurodesis After Bronchial Occlusion for Inoperable Secondary Spontaneous Pneumothorax.

In many cases of secondary spontaneous pneumothorax (SSP), surgery is not feasible. Furthermore, in cases with a collapsed lung or numerous air leaks, pleurodesis is ineffective, and treatment options are severely limited. For these cases, bronchial occlusion might be the only effective treatment, despite the low success rate. If, however, bronchial occlusion can expand the lung and reduce air leakage, it can positively amplify later effects on pleurodesis, resulting in a powerful treatment. We reviewed the clinical data of patients who underwent bronchial occlusion with endobronchial Watanabe spigot (BO-EWS) and pleurodesis to investigate the usefulness of bronchial occlusion therapy in inoperable SSP patients. This single-center, retrospective study reviewed 36 cases of inoperable SSP patients who underwent pleurodesis after BO-EWS from April 2007 to October 2018. Twenty cases were allocated to the air leak analysis group, and 16 cases were included in the pneumothorax volume analysis group. The Robert David Cerfolio classification and the Collins method were used to evaluate air leak and pneumothorax volume, respectively. Pneumothorax volumes decreased significantly after BO-EWS from 29.1%±17.3% to 12.1%±8.8%, while the air leak score decreased from 2.9±1.4 to 1.2±1.0. The success rate for chest tube removals in cases that underwent pleurodesis after BO-EWS was 85.0% (17/20). This study demonstrated the synergistic effectiveness of BO-EWS and the usefulness of pleurodesis treatment in inoperable SSP patients with lung collapse or numerous air leaks. We believe that this treatment will benefit patients with inoperable SSP which, until now, has had few treatment options.

Local lung coagulation post resection: an ex-vivo porcine model

Following non-anatomical resection of lung parenchyma with a Nd:YAG laser, a coagulated surface remains. As ventilation starts, air leakage may occur in this area. The aim of the present study was to investigate, whether additional coagulation either before or after ventilation has an additional sealing effect. Freshly slaughtered porcine heart-lung blocks were prepared. The trachea was connected to a ventilator. Using a Nd:YAG laser (wavelength: 1320 nm, power: 60 W), round lesions (1.5 cm in diameter) with a depth of 1.5 cm were applied to the lung using an 800-μm laser fiber (5 s per lesion). Group 1 (n = 12) was control. Additional coagulation was performed in group 2 (n = 12) without and in group 3 (n = 12) with ventilation restarted. Air leakage (ml) from the lesions was measured. The thickness of each coagulation layer was determined on histological slices. Differences between individual groups were analyzed by one-way ANOVA (significance p < 0.05). After resection, 26.2 ± 2.7 ml of air emerged from the lesions per single respiration in group 1. Air loss in group 2 was 24.6 ± 2.5 ml (p = 0.07) and in group 3 23.7 ± 1.8 ml (p = 0.0098). In comparison to groups 1 and 2 thickness of the coagulation layers in group 3 was significantly increased. After non-anatomical porcine lung resection with a Nd:YAG laser, additional coagulation of the ventilated resection area can reduce air leakage.

Evaluation of underground coal gas drainage performance: Mine site measurements and parametric sensitivity analysis

Underground gas extraction from coal formations has triple-effects involving mining safety, low-carbon gas capture and greenhouse gas control. Air leakage around the drainage borehole is a serious problem that continuously affects gas drainage performance. In this study, mine site measurement of gas drainage data is firstly performed in coal mine, and then a mechanism-based model is proposed to theoretically describe gas desorption and diffusion and flow through coal around the drainage borehole. Further, the propose model is numerically solved and verified with borehole drainage data measured in mine site. Followed this, the validated mechanism-based model is implemented to conduct parametric studies. The results showed that: (a) as the fracture permeability increases from 3 × 10−22 m2 to 3 × 10-14 m2, the air leakage flux increases from 7355 m3/d to 18,303 m3/d, and the gas concentration decreases from 46.9 % to 12.7 %, it indicates that changing the permeability around the borehole may be a wise strategy to control air leakage; (b) the coal matrix parameters (including permeability, sorption constant and radius of matrix) have a dynamic impact on gas drainage performance at the different stage of gas drainage. For example, the increment of methane production induced by increasing the sorption constants does not exceed 3.3 % at the drainage time ∼0.34 day; while the growth increases to more than 19.5 % at the drainage time ∼ 9.75 days; (c) at the initial stage of extraction gas production is mainly determined by the fracture flow. A higher permeability of coal fracture will incur more air leakage flux, reducing gas concentration in drainage borehole; (d) whereas, the matrix parameters dominate gas flow at a later stage. Increasing matrix permeability, sorption property or decreasing the matrix radius will enhance the gas exchange flux from the pore system of coal matrix to the fracture system, subsequently incurring a higher concentration/production of drainage gas. The simulated result and field tests demonstrates that sealing on the coal wall around the borehole can block a portion of air leakage paths and reduce air leakage linearly, which illuminates a more efficient strategy to minimize air leakage for underground gas extraction.

In Vitro Evaluation of Facial Pressure and Air Leak with a Newly Designed Cushion for Non-Invasive Ventilation Masks.

Background: The aim of this study was to evaluate the effect of a newly designed foam cushion on the air leakage and pressure when applied to the face. Methods: A teaching manikin connected to a bilevel positive airway pressure ventilator attached to four different brands of oronasal masks (Amara, Mirage, Forma, and Wizard) was used. The foam cushions of 5-mm and 10-mm-thickness were attached to the masks, and each mask was tested without a cushion. Six pressure sensors were placed on the manikin’s face, and data were recorded. Inspiratory volume and air leak flow from the ventilator were observed. Results: Air leakage was influenced by both the mask brand and the presence of a cushion. The presence of a cushion did not affect the Wizard mask in terms of leakage (p = 0.317) or inspiratory volume (p = 0.726). The Wizard and Amara masks generated the lowest contact pressure on the frontal forehead (p < 0.001) compared to the other five points. Conclusions: Utilisation of a cushion reduces air leakage and maintains greater inspiratory volume regardless of its thickness. The contact pressure varies depending on the brand of the mask, which would require a difference in the thickness of the cushion for pressure reduction.

Comparative Analysis on Performance of Tri-sectional and Four-sectional Air Preheater in 1000MW Unit

This paper mainly compares and analyzes the characteristics and performance of air preheater for tri-sectional and four-sectional, it is found that the four-sectional air preheater has a great advantage in economy, this is mainly because the four-sectional air pre-heater has obvious advantages in reducing air leakage rate, it can reduce air leakage of air preheater, reduce power consumption of fan and improve thermal efficiency of unit significantly. In addition, it is found that the deviation range of flue gas temperature distribution of four-sectional air pre-heater is small by measuring the flue gas side temperature of the air preheater, the overall temperature of flue gas side is higher than that of acid dew point, it is more conducive to the prevention of low-temperature corrosion at the cold end of air preheater, and the operation of the unit is more safe.

Safety of a Novel Microwave Surgical Instrument for Lung Parenchyma Dissection During Segmentectomy

The choice between electrocautery or automatic suturing instruments for dissection of the lung parenchyma along the intersegmental plane during lung segmentectomy remains controversial. We hypothesized that a novel microwave surgical instrument (MSI) for dissecting the lung parenchyma could have excellent sealing effects. We examined the feasibility and safety of lung parenchymal dissection using a MSI during lung segmentectomy. This was a prospective clinical study of lung segmentectomy involving dissection of the entire intersegmental plane using a MSI. Complications related to sealing of the lung parenchyma were evaluated and perioperative outcomes were compared to those of patients who underwent lung segmentectomy using automatic suturing instruments. Propensity score-matched comparisons were used to assess the potential impact of selection bias. Lung segmentectomy using a MSI was successfully performed in 30 patients. According to the propensity score matching analysis, intraoperative blood loss, length of hospital stay, and postoperative complications of the microwave group were significantly lesser (P= .019, .003, and .008, respectively) compared to those of the control group (n= 66). Prolonged air leakage was not observed. There were two cases of subcutaneous emphysema after removal of the chest tube, but no other grade 2 or higher complications were observed. No mortality occurred within 30 or 90 days postoperatively. The use of a MSI for lung parenchymal dissection was associated with lower blood loss during surgical procedures, reduced air leakage after the operation, and fewer postoperative complications.

Design of a New Compressed Air Energy Storage System with Constant Gas Pressure and Temperature for Application in Coal Mine Roadways

Renewable energy (wind and solar power, etc.) are developing rapidly around the world. However, compared to traditional power (coal or hydro), renewable energy has the drawbacks of intermittence and instability. Energy storage is the key to solving the above problems. The present study focuses on the compressed air energy storage (CAES) system, which is one of the large-scale energy storage methods. As a lot of underground coal mines are going to be closed in China in the coming years, a novel CAES system is proposed for application in roadways of the closing coal mines. The new system combines pumped-hydro and compressed-air methods, and features constant air pressure and temperature. Another specific character of the system is the usage of flexible bags to store the compressed air, which can effectively reduce air leakage. The governing equations of the system are derived, and the response of the system is analyzed. According to the equations, for a roadway with depth of 500 m and volume of 10,000 cubic meters, the power generation capacity of the CAES system is approximately 18 MW and the generating time is 1.76 h. The results show that the new CAES system proposed is reasonable, and provides a suitable way to utilize the underground space of coal mines.

The utility of the Stapler with PGA sheet for pulmonary wedge resection: a propensity score-matched analysis.

Air leakage is a common complication after pulmonary wedge resection. The aim of this study was to evaluate the effect of staple line reinforcement in reducing air leakage after pulmonary wedge resection. A retrospective analysis was performed on patients who underwent pulmonary wedge resection. The patients were classified into 2 groups; the Stapler with polyglycolic acid sheet was used for the reinforced and the Stapler without polyglycolic acid sheet was used for the non-reinforced group. The patients were matched one-to-one based on a propensity score that comprised several patient characteristics. A propensity score-matched analysis was performed to compare patient outcomes. A total of 291 patients who met the inclusion criteria were investigated. There were 165 in the reinforced group and 126 patients in the non-reinforced group. Propensity score analysis generated 104 matched pairs of patients in both the reinforced and the non-reinforced groups. The rate of non-placement of chest tube was significantly higher in the reinforced group than in the non-reinforced group (61.5% vs. 36.5%; P<0.001). The rate of postoperative air leakage was higher in the non-reinforced group than in the reinforced group (13.5% vs. 1.9%, P<0.001). On logistic regression analysis, not using the reinforcement device was one of the independent factors related to pulmonary air leakage after pulmonary wedge resection (OR: 8.58, P<0.001). The use of the Stapler with polyglycolic acid sheet during pulmonary wedge resection increased the rate of intraoperative chest tube removal and reduced the rate of postoperative air leakage.

Analyses and prevention of coal spontaneous combustion risk in gobs of coal mine during withdrawal period

Coal spontaneous combustion (CSC) in gob causes notorious safety issues to workers, especially during withdrawal period. Withdrawal period was normally divided into three stages (initial stage, expanding back channel stage and equipment returning stage) when evaluating and preventing the risk of CSC. This study first analyzed the characteristics of ventilation system at each stage, such as oxidized zone movement, local fire wind pressure and air leakage. Then, principles and specialized measurements were applied to minimize the ranges and effects of CSC in gob. In detail, this includes reducing the total air volume flow of mining face in initial stage, adding windscreen in outlet way and local fan in inlet way to increase the pressure of working face, and lowering external air leakage. Considering the working face ventilation area shrinks at equipment returning stage, keeping it bigger than windscreen’s areas can help to reduce air leakage. Further, foamed gel was grouted into gob to narrow and stop the moving forward of oxidized zone. Field application was applied in Zhang Shuang-lou coal mine. Findings of these studies could be used in other coal mine with similar conditions during withdrawal period.

Development law of air leakage fractures in shallow coal seams: a case study in the Shendong Coalfield of China

Continuous air leakage from ground mining-induced cracks is a significant cause of coal spontaneous combustion, low oxygen at the working face and other disasters in shallow coal seams. This paper studies mining-induced cracks and air leakage caused by the repeated mining of shallow coal seams at the Bulianta coal mine, Shendong Coalfield, China. A similar simulation experiment was carried out in the laboratory, and then the ground mining-induced cracks were observed and the crack air leakage was detected. The results showed that the surface air flowed into the composite goaf before the fractures redeveloped to the surface during the process of lower coal seam mining. Due to the different development processes of vertical fractures in various regions, the width of the vertical fractures in the boundary area of the overlying goaf increases significantly after the repeated mining of coal seams, while the vertical fractures in the central area of the overlying goaf experience almost no change. The distribution of the surface air leakage cracks is in the shape of “回”. Graben-type cracks and half-graben-type cracks are surface air leakage cracks, which are the focus of surface air leakage problems, especially the half-graben-type cracks. The results are important in engineering for reducing air leakage from surface mining-induced cracks.

Development of a Poppet-Type Pneumatic Servo Valve

In pneumatic positioning and force-control systems, spool-type servo valves are widely used for obtaining quick responses and precise control. However, air leakage from these valves results in increased energy consumption. To address this problem, we developed a three-port poppet-type servo valve to reduce air leakage. The developed valve consists of a camshaft, two orifices, two metal balls, and a housing with two flow channels. The metal ball is pushed by fluid, and spring force closes the orifice. The port opens when the cam rotates and pushes the ball. The cam shape and orifice size were designed to provide the desired flow rate. The specifications of the DC motor for rotating the camshaft were determined considering the fluid force on the ball. Static and dynamic characteristics of the valve were measured. We experimentally confirmed that air leakage was 0.1 L/min or less. The ratio of air leakage to maximum flow rate was only 0.37%. Dynamic characteristic measurements showed that the valve had a bandwidth of 30 Hz. The effectiveness of the valve was demonstrated through experiments involving pressure and position control.

Airtightness improvement solutions for log wall joints

The air leakage rate of handcrafted log wall and window joint and handcrafted log wall corners using Scandinavian saddle notch or dovetail notch were measured in the laboratory in an airtight measuring chamber. In the first test setup, the joint between the log wall and a window frame was sealed using various commonly practiced methods. Commonly used sealing methods were applied on both corner notches and the joint between logs to evaluate the effectiveness of these sealing methods.The best natural sealing material was peat moss that reduced air leakage of Scandinavian saddle notch by 77% and that of the dovetail notch by 84%. The best modern sealing material was special joint sealant that reduced air leakage of Scandinavian saddle notch by 87% and that of the dovetail notch by 70%. After improving the dovetail notch with PU foam, the air leakage reduced to 94% compared to the original unsealed version.

Cost analysis of pulmonary lobectomy procedure: comparison of stapler versus precision dissection and sealant.

ObjectiveWe aimed to evaluate the direct costs of pulmonary lobectomy hospitalization, comparing surgical techniques for the division of interlobar fissures: stapler (ST) versus electrocautery and hemostatic sealant patch (ES).MethodsThe cost comparison analysis was based on the clinical pathway and drawn up by collecting the information available from the Thoracic Surgery Division medical team at Mantova Hospital. Direct resource consumption was derived from a previous randomized controlled trial including 40 patients. Use and maintenance of technology, equipment and operating room; administrative plus general costs; and 30-day use of postsurgery hospital resources were considered. The analysis was conducted from the hospital perspective.ResultsOn the average, a patient submitted to pulmonary lobectomy costs €9,744.29. This sum could vary from €9,027 (using ES) to €10,460 (using ST). The overall lower incidence (50% vs 95%, P=0.0001) and duration of air leakage (1.7 days vs 4.5 days, P=0.0001) in the ES group significantly affects the mean time of hospital stay (11.0 days vs 14.3 days) and costs. Cost saving in the ES group was also driven by the lower incidence of complications. The main key cost driver was staff employment (42%), then consumables (34%) and operating room costs (12%).ConclusionThere is an overall saving of around €1,432.90 when using ES patch for each pulmonary lobectomy. Among patients undergoing this surgical procedure, ES can significantly reduce air leakage incidence and duration, as well as decrease hospitalization rates. However, further multicenter research should be developed considering different clinical and managerial settings.

Medical and Economic Evaluation of FOREseal Bioabsorbable Reinforcement Sleeves Compared With Current Standard of Care for Reducing Air Leakage Duration After Lung Resection for Malignancy: A Randomized Trial.

The objective of this study was to determine the efficacy of alginate staple-line reinforcement of fissure openings as compared with stapling alone, with or without tissue sealant or glue, in reducing the incidence and duration of air leakage after pulmonary lobectomy for malignancy. No randomized trial evaluating alginate staple-line reinforcement has been performed to date. The Staple-line Reinforcement for Prevention of Pulmonary Air Leakage study was a multicenter randomized trial, with blinded evaluation of endpoints. Patients over 18 years of age scheduled for elective open lobectomy or bilobectomy for malignancy were eligible for enrollment. At thoracotomy, patients were deemed ineligible if an unanticipated pneumonectomy was indicated, or if air leakage occurred after the liberation of pleural adhesions. Otherwise, if the fissure was incomplete or the lung had an emphysematous appearance, patients were randomized to either standard management or interventional procedure consisting of fissure opening with linear cutting staplers buttressed with paired alginate sleeves (FOREseal). The number of eligible patients necessary in each randomization arm was estimated to be 190, and an outcomes analysis was performed on an intention-to-treat basis. Of the 611 patients consented to study enrollment, 380 met the inclusion criteria and were randomized. Based on an intention-to-treat analysis, the primary endpoint of air leak duration was not different between the 2 groups: 1 day (range: 0-2 d) in the FOREseal group and 1 day (range: 0-3 d) in the control group (P = 0.8357). In addition, the 2 groups were similar in terms of the proportion of patients presenting with prolonged air leakage (7.8% in the FOREseal group vs 11.3% in the control group, P = 0.264) and the average duration of chest drainage (P = 0.107). Procedure costs were comparable for both groups. FOREseal did not demonstrate a significant advantage over standard treatment alone.

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

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.