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Biomedical subjects

C A Romaña

Publications and source records attributed to C A Romaña.

8 recordsLinked to original sources
PubMed2006

[Triatominae and Cactaceae: a risk for the transmission of the American trypanosomiasis in the peridomicilary space (Northeast Brazil)].

Field observations carried in semi-arid Brazil Northeast point out the frequent association, in the peridomiciliary space, between a cactus, Cereus jamacaru, the occurrence of nests in its branches and the occurrence of two species of insects vectors of Trypanosoma cruzi, pathogenic agent of Chagas disease: Rhodnius neglectus and Triatoma pseudomaculata. The analysis of the architectural variables of this Cactaceae shows that the presence of nests, and thus of insects, depends on the traditional practices of management of this cactus. This study underlines the relevance of an integrated approach of the ecology of Triatominae for the identification of factors of risk.

Agriculture↗
PubMed1992

[Survival of the human immunodeficiency virus (HIV-1) in Triatoma infestans (Klug, 1834)].

Triatoma infestans is the main domestic vector of Trypanosoma cruzi, the parasitic agent of Chagas' disease in South America. We investigated whether Triatoma infestans could shelter the HIV-1 virus. For this purpose, we measured the survival time of the virus in the alimentary tract. Fifth-instar nymphs of the blood-sucking bug were fed through an ad hoc apparatus with venous blood from asymptomatic HIV-1 seropositive patients. We attempted to evidence the virus by cultivating material from the insect gut (wall and content) on lymphocyte co-culture. Retrovirus activity was demonstrated in the culture supernatant by dosing the p24 antigen and the reverse transcriptase activity. The virus has been found alive in the gut content of Triatoma infestans up to the 7th day after the last infectious meal of the insect.

Animals↗
PubMed1987

[Method of biological control of Triatominae, vectors of Chagas disease, using entomopathogenic Hyphomycetes. Preliminary study].

Bioassays determined the pathogenic activity of 14 strains of 5 entomopathogenic hyphomycetous species (Fungi imperfecti), Beauveria bassiana, Beauveria brongniartii, Metarhizium anisopliae, Nomuraea rileyi and Paecilomyces fumosoroseus to Rhodnius prolixus. Treatments consisted of direct spraying with conidial titrated suspensions on first instar larvae. When tested at 3 X 10(5) conidia/cm2, only 2 strains, B. bassiana n. 297 and B. bassiana n. 326 killed 100% of larvae at 10 days post-exposure. In the same time their LD50 and their LD90 did not differ significantly. After 3 weeks, the mortality caused by either dose of spores of B. bassiana n. 297 was very high. In contrast, in the case of B. bassiana n. 326 mortality due to reduced doses remained at low rates. This laboratory study demonstrated that the isolate, B. bassiana n. 297 might have potential as microbial control agent against the assassin bugs.

Animals↗
PubMedDate not supplied

Relative susceptibility of different stages of Rhodnius prolixus to the entomopathogenic hyphomycete Beauveria bassiana.

Laboratory bioassays were conducted to determine the relative susceptibility of eggs, 1st-, 3rd-, 5th-instar nymphs and adults of Rhodnius prolixus to one isolate of the entomopathogenic hyphomycete, Beauveria bassiana. Treatments consisted of directly spraying on insects of increasing doses of inoculum (3 x 10(2) to 3 x 10(5) conidia per cm2). Mortality due to all doses of conidia was very high in the five tested stages of the target insect. Experiments on eggs demonstrated that the fungal isolate was able to kill eggs before they hatched. Both time-mortality and dose-mortality responses showed that the susceptibility of R. prolixus varied according to its stage of development and increased with age. As a matter of fact, at the dose of 3 x 10(3) conidia per cm2, LD 50 varied between 11.2 days in 1st-instar nymphs and 6.4 days in both 5th-instar nymphs and adults. Comparison of LD50 permitted to estimate that 1st-instar nymphs were about 700-fold less susceptible than the two oldest stages.

Animals↗