Bartonella henselae and the potential for arthropod vector-borne transmission.

INTRODUCTION: Bartonella henselae, the causative agent of the illness referred to as cat scratch disease, is a common infection, particularly in children, and clinicians need to be aware of its potential transmission to humans by arthropod vectors such as fleas and ticks in addition to animal bites and scratches. The absence of a vertebrate bite or scratch does not preclude infection with B. henselae. MATERIALS AND METHODS: Literature regarding arthropod transmission of B. henselae was reviewed. RESULTS: B. henselae appears to be transmitted among cats and dogs in vivo exclusively by arthropod vectors (excepting perinatal transmission), not by biting and scratching. In the absence of these vectors disease does not spread. On the other hand, disease can be spread to humans by bites and scratches, and it is highly likely that it is spread as well by arthropod vectors. DISCUSSION: Clinicians should be aware that a common illness, infection with B. henselae, can be transmitted by arthropod vectors and a history of an animal scratch or bite is not necessary for disease transmission.

Cat scratch disease and arthropod vectors: more to it than a scratch?

PURPOSE: Cat scratch disease is a common infection, particularly in children, and clinicians need to be aware of its potential transmission to humans by arthropod vectors such as fleas and ticks in addition to animal bites and scratches. The absence of a vertebrate bite or scratch does not preclude infection with Bartonella henselae. METHODS: Literature regarding arthropod transmission of B. henselae was reviewed. RESULTS: B. henselae and related bacterial species are transmitted among cats and dogs by arthropod vectors. In the absence of these vectors, disease does not spread amongst the animals. On the other hand, disease can be spread to humans by bite and scratch as well as by arthropod vectors. Animals commonly infected with B. henselae and arthropod vectors are discussed. CONCLUSIONS: Clinicians should be aware that a common illness, cat scratch disease, can be transmitted by arthropod vectors and a history of an animal scratch or bite is not necessary for disease transmission.

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

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.

Feeding behavior of triatomines from the southwestern United States: an update on potential risk for transmission of Chagas disease.

Chagas disease is an emerging infectious disease in North America due to the immigration of individuals from endemic areas. The parasite has been transmitted to patients in non-endemic areas by blood transfusion and organ donation. Only six autochthonous cases have been described in humans in the United States yet the parasite is widespread among native mammals and resident triatomines are competent vectors. We attempted to determine if common southwestern triatomines, Triatoma protracta and Triatoma rubida have the potential to amplify the disease among human residents of the Southwest. The defecation patterns of the bugs were studied while feeding upon immobilized mice. Wild-caught adult male and female triatomines were observed feeding one to three times for a total of 71 observed feedings. T. rubida (15 bugs) appeared to be more aggressive, beginning feeding shortly after being placed in proximity to the host (within 2.3 min) whereas Triatoma protracta (12 bugs) was more deliberate, beginning feeding, on average, at 4 min. There were 40 observations of T. rubida, which fed for 27.9+/-13.6 min, whereas T. protracta fed for 22.8+/-7.5 min (n=31). Bugs were weighed pre- and post-feeding and T. rubida females ingested>T. protracta females>T. rubida males>T. protracta males. Weight gain did not correspond to the feeding duration. Defecation occurred on 42% of the feedings (30 of 71), and no bugs defecated on the host. The majority of the defecations occurred within 1 min of feeding, usually at the time of repletion. A large proportion of defecations occurred after the bugs left the vicinity of the host. All bugs and at least one fecal smear from each feeding bug were tested for Trypanosoma cruzi and 21% of T. protracta were positive by PCR (4 bugs and 1 feces). No T. rubida tested positive for T. cruzi. The bugs' defecation pattern is similar to that reported >50 years ago. Furthermore, there is no indication that they are becoming more domesticated in the desert Southwest. Thus, based on our observations, we do not believe that T. protracta and T. rubida pose an imminent risk for transmission of Chagas disease to residents of the southwestern United States.

Animal bites and stings with anaphylactic potential.

Anaphylaxis to animal bites and stings poses a significant medical risk of vascular or respiratory reactions that vary according to the patient's response and nature of the insult. Emergency Physicians frequently see patients who complain of an allergic reaction to an animal bite or sting. Although Hymenoptera stings, specifically those of wasps, bees, and hornets, account for the majority of these cases, other invertebrates and vertebrates are capable of causing allergic reactions and anaphylaxis. Many of the causative animals are quite unusual, and their bites and stings are not commonly appreciated as potential causes of anaphylaxis. We conducted a literature review to identify documented reports of anaphylaxis and anaphylactoid reactions to animal bites and stings. This summary is meant to heighten awareness of the diversity of animals that may cause anaphylaxis, hopefully leading to more rapid diagnosis and treatment of this dangerous condition. A diverse group of animals was found whose bites and stings cause anaphylaxis and anaphylactoid reactions. Some case summaries are presented. A potentially life-saving plan is to direct patients to proper follow-up care to prevent a future life-threatening reaction, including: prescribing epinephrine and antihistamines with proper instructions for their use; referral to an allergist to determine if skin testing, radioallergosorbent test, and immunotherapy are indicated; and reporting the case to state or local Poison Control Centers. In some cases it may be helpful to consult an entomologist or a pest control service for help in identification and elimination of certain offenders.

Adverse reactions to ants other than imported fire ants.

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.

Fluticasone propionate HFA-134a pressurized metered-dose inhaler in adolescents and adults with moderate to severe asthma.

In this randomized, double-blind, placebo-controlled trial, 397 patients with moderate to severe asthma, previously treated with bronchodilators alone, received fluticasone propionate 88, 220, or 440 microg twice daily, or placebo via metered dose inhaler (MDI) for 12 weeks. Mean change from baseline to endpoint in pre-dose percent predicted forced expiratory volume in one second (FEV1) was greater (p < 0.001) in each fluticasone propionate group (9.0%, 88 microg bid; 9.8%, 220 microg bid; 11.2%, 440 microg bid) versus placebo (3.4%). Morning and evening peak expiratory flow (PEF), asthma symptoms, and supplemental albuterol use also improved in all fluticasone propionate groups versus placebo. The incidence of adverse events and 24-hour urine cortisol excretion rates were similar between active treatments and placebo.