Margarita Cabrera Bravo

Universidad Nacional Autónoma de México, Ciudad de México, The Federal District, Mexico

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Publications (5)3.7 Total impact

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    ABSTRACT: Two cases of acute Chagas disease in schoolchildren of 6 and 13 years of age, both with the clinical features of Romaña's sign, regional lymphadenopathy, and fever, have a history of coexistence and the bite of the transmitter, and live in housing constructed with material considered at risk for infestation by the vector; i.e. roof and walls with palma/zacate (palm tree, grass leaves), dirt floor, and inadequate illumination and ventilation. The parasitological diagnosis of both cases was established by identification of trypomastigotes of Trypanosoma cruzi in blood smears and the parasite was isolated in one of them. Benznidazole treatment was administered according to the guidelines of the WHO/PAHO for this disease. The presence of acute Chagas disease in rural areas confirms the active transmission of the parasite, so surveillance and epidemiological controls should be applied. The importance of these cases is that T. cruzi infection is symptomatic in 5% of cases, which implies that a high percentage of cases of infection appear asymptomatic and are not being diagnosed in our country.
    Gaceta medica de Mexico 01/2011; 147(1):63-9. · 0.13 Impact Factor
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    ABSTRACT: Several biological parameters related to the Triatoma mexicana life-cycle were evaluated in this study. Three cohorts were maintained under different combinations of temperature and relative humidity (RH): 25 degrees C/50% RH; 25 degrees C/75% RH; and 30 degrees C/75% RH. Observed hatching rates varied from 49-57.5% whereas the average time of hatching varied from 19.5-22.7 days. In the three cohorts studied, the mean time-lapse between presentation of the blood meal and the beginning of feeding was less than 5 min in all instars; the mean feeding time was longer than 10 min in all the instars; the post-feed defecation delay was over 10 min in all the instars. Less than 50% of nymphs in each cohort completed the cycle and the average time from 1st instar nymph to adult was more than 255 days for the three cohorts. The number of blood meals before molt at each nymphal instar varied from 1-9. Our results appear to indicate a lack of influence of temperature and RH on the biological parameters of T. mexicana that were studied, which could reflect the adaptation capacity of this species. We also conclude that T. mexicana can not be considered an effective transmitter of Trypanosoma cruzi to human populations in areas where this species is currently present.
    Memórias do Instituto Oswaldo Cruz 12/2008; 103(7):719-23. · 1.36 Impact Factor
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    ABSTRACT: Triatoma mexicana was described by Herrich-Schaeffer in 1848. In 1940, a male specimen was found in Hidalgo. In 1970, this species was recorded in the state of Queretaro. Later, it was registered in Guanajuato and San Luis Potosi. In the present paper we performed an investigation in 545 dwellings from three counties in the state of Guanajuato, Mexico, from March 2003 to May 2004. The search and capture of triatomines were seasonally performed indoors and outdoors. Entomological indexes were calculated. The risk and no risk relations between triatomine presence and housing construction materials were analyzed. Fourteen triatomines were collected indoors and 151 outdoors. The vectors were collected in houses built with either risky and non-risky materials. Adults go indoors but do not settle there, hence, no relationship was found between the building materials and infestation of houses. Conventional interventions like house improvement or insecticide spraying are not efficient for the control of T. mexicana, because its developmental cycle is accomplished outdoors in the area surrounding the houses.
    Memórias do Instituto Oswaldo Cruz 12/2007; 102(7):803-7. · 1.36 Impact Factor
  • Medicina 03/2005; 65(1):63-69. · 0.42 Impact Factor
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    ABSTRACT: Observations made in the field and in the laboratory on three vectors of Trypanosoma cruzi: Triatoma barberi, T. pallidipennis and T. dimidiata are here presented. Results are compared in relation with their ecotopes, vectorial capacity, biological characteristic, entomological indexes and capture places. In relation with their ecotopos T. barberi has preference for the interior of the human home, in walls, directly in contact with beds; T. pallidipennis, when it is inside the houses, prefers floors and among clothes, although their main ecotope is wild; T. dimidiata has localization in floors, specially under the beds, in the angle between wall and floor; T. barberi and T. dimidiata are attracted by the light. The cycles of life were of 523, 171 and 510 days, respectively for Triatoma barberi, T. pallidipennis and T. dimidiata. The vectorial capacity was determined according to the time taken in defecating during or after its sucking blood: T. barberi defecates during its feeding, while T. pallidipennis and T. dimidiata make it from 10 to 20 and of 20 to 30 minutes after starting the process, respectively. The indexes of natural infection were of 56.6 for T. barberi, 29 for T. pallidipennis and 15.6 for T. dimidiata, The metacyclogenics indexes that indicate percentages of metacyclics trypomastigotes in later intestine of vectors was in T. barberi 76.6, T. pallidipennis 15 and T. dimidiata 26, with what it can be concluded that the first species is the best transmitter of T. cruzi in Mexico.
    Medicina 02/2005; 65(1):63-9. · 0.42 Impact Factor