Nocturnal Flights of TRIATOMA (Hemiptera: Reduviidae) in Sabino Canyon, Arizona

Three species of Triatorna were studied in this investigation: T. rubida uhleri (Neiva), _T. protracta protracta (Uhler), and T. recurva (Stal) (Hemiptera:Reduviidae). These blood-sucking bugs are ectoparasites of vertebrate animals. Triatoma rubida uhleri (Neiva) is the most common conenose bug in southern Arizona. At certain seasons of the year Triatoma bugs enter homes and bite people causing an allergic reaction in sensitized individuals. The purpose of this study was to determine cause of flight, time of day and r season of the year most individuals fly, effects of various physical factors on flights and distances flown. This research was conducted at lights in Sabino Canyon, northeast of Tucson, Arizona. A black light was operated 4 to 6 nights per week during the summers of 1972 and 1973. For each Triatoma bug collected physical conditions (temperature, relative humidity, cloud cover, moonlight, wind speed and direction) and time of arrival were noted. Computer analysis of the data was performed using programs written in FORTRAN IV and a prepared program (BMD 02R) from UCLA Health Sciences Computing Facility. Lodges of Neotoma albigula Hartley, the natural host of Triatoma rubida and TT. protracta protracta, were examined for the presence of bugs during all seasons of the year. Seventy-nine lodges were examined. A total of 1107 Triatominae were collected at lights and traps and 941 from Neotoma lodges. Twelve species of reduviids other than Triatominae were also collected at the black lights. Three species of buprestids were collected on sticky traps. Desert tortoises. banded geckos and scorpions were found in Neotoma lodges. Triatoma rubida uhleri bugs overwinter as 5th instar nymphs. As soon as average temperatures warm up to 23° to 25°C, the 5th instar nymphs begin molting to adults. This produces large numbers of adult bugs in early summer. T. rubida has a short adult life span; by fall very few adult bugs are left alive. Triatoma flights appear to be due to starvation. If adult bugs find themselves without a wood rat host, they become starved within approximately 15 days following their last blood meal. Because the Neotoma move about from lodge to lodge, and furthermore because of predation on them by owls, snakes, and bobcats, the Triatoma may be without hosts for extended periods of time. With very few exceptions. bugs arrive at the light in a starved condition and die within a few days. if not fed. Time of day (or amount of light) is a limiting factor in bug flights. The vast majority of Triatominae bugs in this study were collected in the first 4 hours after dark. Only 5 bugs were received before zero footcandles of light. The most important physical factors promoting the flight of T.rubida are high temperatures, low relative humidity and low wind speeds. For T.recurva the factors promoting flights are temperatures in the range 22° to 35°C and low relative humidity

Infection of Kissing Bugs with Trypanosoma cruzi, Tucson, Arizona, USA

A survey of triatomine insects found that 41.5% were infected with the causative agent of Chagas disease

Immune Events Associated with High Level Protection against Schistosoma japonicum Infection in Pigs Immunized with UV-Attenuated Cercariae

BACKGROUND: The vaccination of radiation-attenuated Schistosoma japonicum cercariae can induce effective protection in artiodactyl, but the immune events related to protective immunity are not fully understood. To provide a paradigm for a human recombinant antigen vaccine, we have undertaken a vaccination and challenge experiment in pigs, which was recognized as an appropriate animal model in this type of study because of their similarity to human in immunology, and investigated the relative immune events induced by the radiation-attenuated S. japonicum cercariae. METHODS AND FINDINGS: We found that pigs immunized once with 400 µw UV-irradiated cercariae exhibited 63.84% and 71.82% reductions in worm burden and hepatic eggs respectively. Protective immunity in vaccinated pigs was associated with high level productions of IgM, total IgG, IgG1 and IgG2; IgG2 was significantly increased in the acute infection. IFN-γ levels could be elicited by immunization. At week 6 post-infection, IFN-γ, IL-4 and IL-10 levels also showed a dramatic rise synchronously in vaccinated pigs. Moreover, the granzyme b, nk-lysin, ifnγ, il4 and il10 mRNA levels in early skin-draining lymph nodes of immunized pigs were higher than those in pigs with non-irradiated cercariae infection. In addition, cytotoxicity-related genes in the mesenteric lymph nodes were significantly upregulated in vaccinated pigs in the acute infection. CONCLUSION/SIGNIFICANCE: Our results demonstrated that IFN-γ and IgG2 antibody production, as well as genes related to cytotoxicity are associated with the high level protection induced by UV-irradiated Schistosoma japonicum vaccine. These findings indicated that optimal vaccination against S. japonicum required the induction of IFN-γ, IgG2 antibody related to Th1 responses and cytotoxicity effect

Inducible deletion of CD28 prior to secondary nippostrongylus brasiliensis infection impairs worm expulsion and recall of protective memory CD4 (+) T cell responses

IL-13 driven Th2 immunity is indispensable for host protection against infection with the gastrointestinal nematode Nippostronglus brasiliensis. Disruption of CD28 mediated costimulation impairs development of adequate Th2 immunity, showing an importance for CD28 during the initiation of an immune response against this pathogen. In this study, we used global CD28−/− mice and a recently established mouse model that allows for inducible deletion of the cd28 gene by oral administration of tamoxifen (CD28−/loxCre+/−+TM) to resolve the controversy surrounding the requirement of CD28 costimulation for recall of protective memory responses against pathogenic infections. Following primary infection with N. brasiliensis, CD28−/− mice had delayed expulsion of adult worms in the small intestine compared to wild-type C57BL/6 mice that cleared the infection by day 9 post-infection. Delayed expulsion was associated with reduced production of IL-13 and reduced serum levels of antigen specific IgG1 and total IgE. Interestingly, abrogation of CD28 costimulation in CD28−/loxCre+/− mice by oral administration of tamoxifen prior to secondary infection with N. brasiliensis resulted in impaired worm expulsion, similarly to infected CD28−/− mice. This was associated with reduced production of the Th2 cytokines IL-13 and IL-4, diminished serum titres of antigen specific IgG1 and total IgE and a reduced CXCR5+ TFH cell population. Furthermore, total number of CD4+ T cells and B220+ B cells secreting Th1 and Th2 cytokines were significantly reduced in CD28−/− mice and tamoxifen treated CD28−/loxCre+/− mice compared to C57BL/6 mice. Importantly, interfering with CD28 costimulatory signalling before re-infection impaired the recruitment and/or expansion of central and effector memory CD4+ T cells and follicular B cells to the draining lymph node of tamoxifen treated CD28−/loxCre+/− mice. Therefore, it can be concluded that CD28 costimulation is essential for conferring host protection during secondary N. brasiliensis infection

Peruvian Treehopper Behavior Homoptera Membracidae

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