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DISTRIBUCION TOPOGRAFICA DE Pimeliaphilus zeledoni (ACARI: PTERYGOSOMATIDAE) EN SU HOSPEDADOR Triatoma dimidiata (LATREILLE, 1811) (HEMIPTERA: REDUVIIDAE)
CALDERON-ARGUEDAS,OLGER;
Parasitología al día , 1998, DOI: 10.4067/S0716-07201998000300005
Abstract: topographic distribution of pimeliaphilus zeledoni (acari: pterygosomatidae) on its host triatoma dimidiata (latreille, 1811) (hemiptiera: reduviidae) a characterization of pimeliaphilus zeledoni infestation on costarican triatoma dimidiata was done. the prevalence of p. zeledoni on 47 collected bugs was 53.2%. the triatominae evolutive-forms that presented the highest levels of infestation were the 5° instar nymphs. the larvae were the more abundant forms of the mite (a 0.05). the coxae were the morphological sites of the bugs where the mites were preferentially located. there were not evidences of important pathogenic effects generated by the mites on the triatominae. this the reason because the biological control with this mite should be debated.
Environmental management for the control of Triatoma dimidiata (Latreille, 1811), (Hemiptera: Reduviidae) in Costa Rica: a pilot project
Zeledón, Rodrigo;Rojas, Julio C;
Memórias do Instituto Oswaldo Cruz , 2006, DOI: 10.1590/S0074-02762006000400006
Abstract: an ecological control method, using environmental management operations, based on biological and behavioral characteristics of triatoma dimidiata (latreille, 1811), was implemented as a pilot project in an area of costa rica where the bug is prevalent. the sample was represented by 20 houses with peridomestic colonies (two also had indoor infestation), divided in two equivalent groups of 10 each. in one group we intervened the houses, i.e. all objects or materials that were serving as artificial ecotopes for the bugs were removed, and the second group was used as control houses. after a year of periodic follow up, it became evident that in those houses with a modified environment the number of insects had decreased notoriously even after the first visits and this was more evident after a period of 12.5 to 13.5 months in which no insects were detected in eight of the houses. it also became clear that in this group of houses, recolonization by wild bugs from the surrounding areas, became more difficult, probably due to the absence of protection from bug predators. in the control houses, with the exception of three in which the inhabitants decided to intervene on their own, and another house with a peculiar situation, the insect populations remained the same or even showed a tendency to increase, as confirmed at the end of the experiment. we believe that the method is feasible, low costing and non contaminating. it could be used successfully in other places where t. dimidiata is common and also in countries where other species colonize peridomestic areas of homes. environmental management of this kind should seek the participation of the members of the communities, in order to make it a more permanent control measure.
DISTRIBUCION TOPOGRAFICA DE Pimeliaphilus zeledoni (ACARI: PTERYGOSOMATIDAE) EN SU HOSPEDADOR Triatoma dimidiata (LATREILLE, 1811) (HEMIPTERA: REDUVIIDAE)
OLGER CALDERON-ARGUEDAS
Parasitología al día , 1998,
Abstract: RESUMEN Se realizó una caracterización de la infestación de P. zeledoni en ejemplares costarricenses de T. dimiata. La prevalencia de infestación encontrada en 47 chinches fue del 53,2%, siendo las ninfas de 5° estadio las formas evolutivas que mostraron la densidad de infestación más alta (a 0,05). Las coxas constituyeron el sitio anatómico de los insectos donde los ácaros se localizaron preferencialmente. No se pudo determinar la presencia de efectos patogénicos importantes generados por los ácaros en los triatominos por lo que su aplicación en su control biológico debería ser reconsiderada. TOPOGRAPHIC DISTRIBUTION OF Pimeliaphilus zeledoni (ACARI: PTERYGOSOMATIDAE) ON ITS HOST Triatoma dimidiata (LATREILLE, 1811) (HEMIPTIERA: REDUVIIDAE) A characterization of Pimeliaphilus zeledoni infestation on costarican Triatoma dimidiata was done. The prevalence of P. zeledoni on 47 collected bugs was 53.2%. The triatominae evolutive-forms that presented the highest levels of infestation were the 5° instar nymphs. The larvae were the more abundant forms of the mite (a 0.05). The coxae were the morphological sites of the bugs where the mites were preferentially located. There were not evidences of important pathogenic effects generated by the mites on the triatominae. This the reason because the biological control with this mite should be debated.
Evidence of colonization of man-made ecotopes by Triatoma dimidiata (Latreille, 1811) in Costa Rica
Zeledón, Rodrigo;Montenegro, Víctor M;Zeledón, Oswaldo;
Memórias do Instituto Oswaldo Cruz , 2001, DOI: 10.1590/S0074-02762001000500012
Abstract: triatoma dimidiata adults have been frequently found, during the last five years, in a dog kennel and a chicken coop, in the back yard of a well-built house, 15 km from san josé, the capital of costa rica. in the chicken coop nymphs were also found. two of the 11 dogs from the kennel were serologically positive for trypanosoma cruzi infection. the inhabitants of the house, three adults and two children, were negative. this type of colonization by the insect, which is attracted to lights, is becoming common in old and new settlements, with different degrees of success, a fact with epidemiological implications and great relevance in the control strategies that can be applied.
Evidence of colonization of man-made ecotopes by Triatoma dimidiata (Latreille, 1811) in Costa Rica
Zeledón Rodrigo,Montenegro Víctor M,Zeledón Oswaldo
Memórias do Instituto Oswaldo Cruz , 2001,
Abstract: Triatoma dimidiata adults have been frequently found, during the last five years, in a dog kennel and a chicken coop, in the back yard of a well-built house, 15 km from San José, the capital of Costa Rica. In the chicken coop nymphs were also found. Two of the 11 dogs from the kennel were serologically positive for Trypanosoma cruzi infection. The inhabitants of the house, three adults and two children, were negative. This type of colonization by the insect, which is attracted to lights, is becoming common in old and new settlements, with different degrees of success, a fact with epidemiological implications and great relevance in the control strategies that can be applied.
Ecological control of Triatoma dimidiata (Latreille, 1811): five years after a Costa Rican pilot project
Zeledó, Rodrigo;Rojas, Julio C;Urbina, Andrea;Cordero, Marlen;Gamboa, Sue H;Lorosa, Elias S;Alfaro, Sergio;
Memórias do Instituto Oswaldo Cruz , 2008, DOI: 10.1590/S0074-02762008000600020
Abstract: an ecological pilot project for the control of triatoma dimidiata allowed a new evaluation four and five years after environmental modifications in the peridomestic areas of 20 households. it was verified that the two groups of houses, 10 case-houses and 10 control-houses, were free of insects after those periods of time. in the first group, the owners started a chicken coop in the backyard and a colony of bugs was found there without infesting the house. in the second group, the inhabitants of one house once again facilitated the conditions for the bugs to thrive in the same store room, reaffirming that man-made ecotopes facilitates colonization. this ecological control method was revealed to be reliable and sustainable and it is recommended to be applied to those situations where the vectors of chagas disease can colonize houses and are frequent in wild ecotopes.
Morphological study of the eggs and nymphs of Triatoma dimidiata (Latreille, 1811) observed by light and scanning electron microscopy (Hemiptera: Reduviidae: Triatominae)
Mello, F;Jurberg, J;Grazia, J;
Memórias do Instituto Oswaldo Cruz , 2009, DOI: 10.1590/S0074-02762009000800003
Abstract: eggs and nymphs of triatoma dimidiata were described using both light and scanning electron microscopy. the egg body and operculum have an exochorion formed by irregular juxtaposed polygonal cells; these cells are without sculpture and the majority of them are hexagonal in shape. the five instars of t. dimidiatacan be distinguished from each other by characteristics of the pre, meso and metanotum. the number of setiferous tubercles increases progressively among instars. the sulcus stridulatorium of 1st instar nymphs is amorphous, showing median parallel grooves; from the 2nd instar on the sulcus is, progressively, elongate, deep and posteriorly pointed with stretched parallel grooves. all instars have a trichobothrium on the apical 1/3 of segment ii of the antenna. the opening of the brindley's gland is on the mesopleura. fifth instar nymphs have an apical ctenidium on the ventral surface of the fore tibia. dorsal glabrous patches are found on the lateral 1/3 of abdomen. bright oval patches are found on the ventral median line of the abdomen, from segment iv-vi; 1st instar nymphs lack these patches. abdominal dorsal plates are present from the 1st-5th instars; the 1st instar also contains a rectangular plate in segment ix. from the 2nd instar on, variably-shaped plates are present on segments vii to ix. morphometric data were also obtained and proved to be useful for distinguishing t. dimidiata instars.
Epidemiology of Chagas disease in Guatemala: infection rate of Triatoma dimidiata, Triatoma nitida and Rhodnius prolixus (Hemiptera, Reduviidae) with Trypanosoma cruzi and Trypanosoma rangeli (Kinetoplastida, Trypanosomatidae)
Monroy, Carlota;Rodas, Antonieta;Mejía, Mildred;Rosales, Regina;Tabaru, Yuichiro;
Memórias do Instituto Oswaldo Cruz , 2003, DOI: 10.1590/S0074-02762003000300003
Abstract: a five-year domiciliary collection in the 22 departments of guatemala showed that out of 4,128 triatomines collected, 1,675 were triatoma dimidiata (latreille, 1811), 2,344 were rhodnius prolixus stal 1859, and only 109 were t. nitida usinger 1939. the chagas disease parasite, trypanosoma cruzi, was found in all three species. their natural infection rates were similar in the first two species (20.6%; 19.1%) and slightly lower in t. nitida(13.8%). however there was no significant difference in the infection rates in the three species (p = 0.131). t. dimidiata males have higher infection rates than females (p = 0.030), whereas for r. prolixus there is no difference in infection rates between males and females (p = 0.114). the sex ratios for all three species were significantly skewed. more males than females were found inside houses for t. dimidiata (p < 0.0001) and t. nitida (p = 0.011); a different pattern was seen for r. prolixus (p = 0.037) where more females were found. sex ratio is proposed as an index to show the mobility of t. dimidiata in different populations. t. dimidiata is widely distributed in the country, and is also the main vector in at least ten departments, but r. prolixus with higher vectorial capacity is an important vector in at least two departments.
Epidemiology of Chagas disease in Guatemala: infection rate of Triatoma dimidiata, Triatoma nitida and Rhodnius prolixus (Hemiptera, Reduviidae) with Trypanosoma cruzi and Trypanosoma rangeli (Kinetoplastida, Trypanosomatidae)
Monroy Carlota,Rodas Antonieta,Mejía Mildred,Rosales Regina
Memórias do Instituto Oswaldo Cruz , 2003,
Abstract: A five-year domiciliary collection in the 22 departments of Guatemala showed that out of 4,128 triatomines collected, 1,675 were Triatoma dimidiata (Latreille, 1811), 2,344 were Rhodnius prolixus Stal 1859, and only 109 were T. nitida Usinger 1939. The Chagas disease parasite, Trypanosoma cruzi, was found in all three species. Their natural infection rates were similar in the first two species (20.6%; 19.1%) and slightly lower in T. nitida(13.8%). However there was no significant difference in the infection rates in the three species (p = 0.131). T. dimidiata males have higher infection rates than females (p = 0.030), whereas for R. prolixus there is no difference in infection rates between males and females (p = 0.114). The sex ratios for all three species were significantly skewed. More males than females were found inside houses for T. dimidiata (p < 0.0001) and T. nitida (p = 0.011); a different pattern was seen for R. prolixus (p = 0.037) where more females were found. Sex ratio is proposed as an index to show the mobility of T. dimidiata in different populations. T. dimidiata is widely distributed in the country, and is also the main vector in at least ten departments, but R. prolixus with higher vectorial capacity is an important vector in at least two departments.
Efecto tóxico de beta-cipermetrina, deltametrina y fenitrotión en cepas de Triatoma dimidiata (Latreille, 1811) y Triatoma maculata (Erichson, 1848) (Hemiptera, Reduviidae)
Reyes,Marlene; Angulo,Víctor Manuel; Sandoval,Claudia Magaly;
Biomédica , 2007,
Abstract: introduction. the susceptibility to insecticides of triatomine species must be evaluated because of their involvement in the transmission of the chagas disease. in each region with chagas endemicity, evaluation of insecticide response is necessary to predict the success of the control campaigns. objective. the baseline susceptibility was determined for the active principles deltamethrin, b-cypermethrin and fenitrothion in nymphs of first and fifth instar of triatoma dimidiata and nymphs of first instar of triatoma maculata. materials and methods. the insecticide activity in triatomines was evaluated by the technique of topical application. results. the values of the ld50 in nymphs of first instar for t. maculata, expressed in nanograms per insect (ng/i), were 0.07, 0.05 and 4.12 for deltamethrin, b-cypermethrin and fenitrothion respectively. the corresponding ld99 values were 1.08, 0.37 and 17.89 ng/i. in t. dimidiata, the ld50 values were 0.44, 0.46 and 16.45 ng/i; the ld99 values were 2.22, 1.97 and 36.07 ng/i. in nymphs of fifth instar t. dimidiata, the ld50 values were 510.7, 1,623.6 and 838.9 ng/i; the ld99 values were 9,607.5, 11,717.9 and 1,525.0 ng/i, respectively. conclusion. in first instar nymphs of t. dimidiata and t. maculata, the pyrethroid insecticides were more effective; in fifth instar nymphs of t. dimidiata, the effectiveness of the pyrethroids and the organophosphate differed in the ld50 comparison-the nymphs required much higher doses compared with the other triatomines and suggested a low susceptibility. the ld99 for the organophosphate (fenitrothion) was significantly lower and may indicate its greater effectiveness in field. studies of synergistic effects amonst insecticides are important to clarify the role of biochemical mechanisms that determine tolerance to the pyrethroids. insecticide tolerance represents a new challenge for control campaigns in the andean and central american countries where chagas disease is endemic.
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