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PubMedDate not supplied

[Triatoma delpontei Romaña & Abalos, 1947 (Hemiptera, Tratominae) in the Brazilian State of Rio Grande do Sul].

Triatoma delpontei (Romaña & Abalos, 1947) (Hemiptera, Triatominae) is an ornithophilic sylvatic with a particular association to the psittacid Myiopsitta monachus (Boaddert, 1783). It is found in the continental biogeographical province of the Chaco, where it inhabits the nests or M. monachus, in subtropical xerophytic forests. The authors report the first finding of T. delpontei in Brasil, in the "campanha" region of the State or Rio Grande do Sul (Barra do Quarai, Uruguaiana), on the right bank of the River Cuareim, not far from de Uruguayan border.

Animals↗
PubMedDate not supplied

Chagas' disease in the Brazilian Amazon. II. A serological survey.

A serological survey, involving indirect immunofluorescence testing of blood sera samples, was carried out on the residents of one in every five dwellings in the town of Barcelos (in the northern part of the State of Amazonas, on the right bank of the Rio Negro, 490 Km from Manaus by river) and on the rural populations of the villages of Piloto and Marará (also on the right bank of the Rio Negro, 30 minutes by boat from Barcelos). A total of 710 sera samples were tested, 628 from the resident population in the town of Barcelos, 35 from Piloto and 47 from Marará. The tests were carried out using human anti-gammaglobulin type IgG (Biolab) and antigen from formolized culture of T. cruzi Y strain. The sera were serially diluted from 1:40 to 1:320 in PBS 7.2. Of the 710 samples examined 89 (12.5%) were positive for anti-T.cruzi antibodies: 2 of these (2.2%) at a dilution of 1:320; 12 (13.4%) at 1:160; 38 (42.6%) at 1:80; and the remainder at 1:40, giving a median serological dilution of 1:80. The following questions are discussed: the high serological prevalence for Chagas' infection found in our survey; the possibility of serological cross-reactions; the need for confirmatory tests for the positives reactions; and the strong correlation between our results and preliminary epidemiological data (such as the level of human contact with wild triatominae, know locally as "Piaçava's lice". We draw attention to the isolation by xenodiagnosis of one strain of T.cruzi from a patient with positive serology for Chagas' infection.

Adolescent↗
PubMedDate not supplied

Seropositivity for anti-trypanosoma cruzi antibodies among blood donors of the "Hospital Universitário Regional do Norte do Paraná", Londrina, Brazil.

The most frequent form of acquisition of Chagas' disease in endemic areas was the transmission through the feces of contaminated triatominae. However, special attention should be paid in urban areas to transmission by blood transfusion, justifying the compulsory screening of blood donors. Early investigations at blood banks in the town of Londrina, Brazil, demonstrated that the seroprevalence of anti-Trypanosoma cruzi antibodies among blood donors was approximately 7.0% in the fifties. Further studies demonstrated practically the same seroprevalence until the eighties. In an attempt to obtain data about the real dimension of the seropositivity for anti-Trypanosoma cruzi antibodies in the region, the authors carried out a large-scale study on 45,774 serum samples from blood donors of the Hemocentro of Hospital Univesitário Regional do Norte do Paraná (HURNP), Universidade Estadual de Londrina. The immunological tests were done at the Division of Clinical Immunology of HURNP from May 1990 to December 1994. The serum samples were studied by the indirect hemagglutination assay (IHA, using kits commercially obtained from EBRAM) and by indirect immunofluorescence (IFI, using kits from LIO SERUM) with anti-human IgG conjugate (LABORCLIN). The results demonstrated that 643 serum samples were positive in both assay corresponding to a seroprevalence of 1.4%, i.e., a significant decrease in anti-Trypanosoma cruzi antibodies in the region in comparison with the previously mentioned rates. Data correlating sex and age of seropositive blood donors are presented, as well as the possible factors that may have contributed to the results observed.

Adolescent↗
PubMedDate not supplied

[Chagas' disease in Lassance, Minas Gerais State: Clinical-epidemiological re-evaluation ninety years after the discovery by Carlos Chagas].

The history and present situation of Chagas' disease in Lassance (the county where Carlos Chagas discovered American trypanosomiasis) were studied through a historical analysis and clinical and epidemiological research performed from 1999 to 2001. Lassance was an important focus of Chagas' disease from Carlos Chagas up until the 1980's, because of intensive infestation in dwellings by Panstrongylus megistus and Triatoma infestans, two important species which were efficiently controlled in the last twenty years. Human Chagas' disease was important in the past but today is only residual, affecting basically the more elderly age groups. The general prevalence is about 5.03% and no infected individuals are found below 20 years of age. The clinical and epidemiologic profile of the seropositive individuals studied is that expected in areas with interrupted transmission, most of these presenting the indeterminate or benign cardiac form of chronic Chagas' disease. Some cases of digestive Chagas' disease also seem to exist. Mortality due to the disease is still significant, affecting chiefly older age groups. The municipality still remains infested by Triatoma sordida, in low densities and high dispersion, non infected by T. cruzi and restricted to peridomestic foci. In conclusion, Lassance is now free of Chagas' disease transmission and must improve medical attention for the remaining infected individuals, as well as to maintain a permanent epidemiological surveillance against native Triatominae.

Adolescent↗
PubMedDate not supplied

[A matched study of Chagas' cardiopathy in Rio Grande do Sul, Brazil. Behavior of electrocardiographic changes according to the skin color].

The pattern of ECG changes of 150 black individuals from rural areas of southern Rio Grande do Sul, Brazil, was compared with that of a group of 150 whites of similar age, sex and geographical residence. The mean age of the study group was 39.2 years (9-78 years), and 62% were women. 84 out of the 150 showed positive serological reactions to infection by Trypanosoma cruzi. The prevalence of ECG changes was significantly higher among the blacks, irrespective of their serological state. Those changes which were considered as suggestive of Chagas cardiopathy were more common among blacks with positive serological reactions. Blacks with seronegative reactions had more frequent ECG changes which were of increased severity, than those of whites with negative reactions. The increased prevalence and severity of ECG changes among black might be attributed to several factors, including: higher levels of poverty, leading to strenuous working conditions; poorer housing quality facilitating infestations by triatominae; inadequate feeding habits. In addition, the increased levels of arterial tension found among the blacks, might be associated with possible racial factors, in collaborating to increase the likelihood of myocardial lesions.

Adolescent↗
PubMedDate not supplied

Feeding and defaecation patterns in Triatoma sordida.

Triatoma sordida is a peridomestic Triatominae that could play an important role in the transmission of Trypanosoma cruzi, although its vectorial competence is not well known. The aim of this work was to evaluate two aspects of the vectorial competence: the feeding behaviour and defaecation patterns, and to compare them with T. infestans. The feeding and defaecation patterns were studied in adults and fifth instar nymphs of T. sordida fed ad libitum on a restrained pigeon. The results showed how the blood meal size controls excretion behaviour. Blood intake and time to first defaecation showed a significant negative correlation. Adults and nymphs frequently defaecated during the blood meal, reaching the maximum frequency within the first 10 minutes.

Animals↗
PubMedDate not supplied

Haematophagy and cleptohaematophagy of clerada apicicornis (Hemiptera: lygaeidae), a potential biological control agent of rhodnius prolixus (Hemiptera: reduviidae).

Because of its ability to prey on Triatominae in rural houses, Clerada apicicornis has been suggested as a potential biological control agent of Rhodnius prolixus. It has also been suggested as a potential vector of mammalian trypanosomes such as Trypanosoma cruzi, because of its ability to take blood directly from mammals. To help resolve these conflicting ideas, we assessed the haematophagic behaviour of C. apicicornis by carrying out feeding trials on laboratory animals. Cleptohaematophagic behaviour was also assessed by allowing C. apicicornis to feed on R. prolixus previously engorged with avian blood. The low proportion of blood meals taken directly from laboratory animals indicates a facultative haematophagy in this species, whereas a greater proportion of nymphs and adults were able to obtain vertebrate blood by predation on engorged R. prolixus. The results suggest that C. apicicornis is unlikely to be effective as a biological control agent, but is also unlikely to have a significant role in the transmission of vertebrate pathogens.

Animals↗
PubMedDate not supplied

Monitoring the domiciliary and peridomiciliary invasion process of Triatoma rubrovaria in the State of Rio Grande do Sul, Brazil.

The presence of Triatoma rubrovaria in Brazil has only been confirmed in the States of Paraná and Rio Grande do Sul (RS), where it is found naturally infected with Trypanosoma cruzi. In the wild environment it occurs in rocky habitats and has an eclectic diet, feeding from cockroaches, reptiles and mammals. Data from the Chagas Disease Control Program obtained by the Fundação Nacional de Saúde, between 1975 and 1997, indicate a growing domiciliary and peridomiciliary invasion of T. rubrovaria in RS, where it has become the most frequently Triatominae species captured in this state since the control of Triatoma infestans. In order to monitor this process, we analyzed collection data derived from 22 years of control campaigns against T. infestans. Collection data for triatomines from domestic habitats show an inverse relationship, with high numbers of T. infestans and low numbers of T. rubrovaria during 1976-1987, compared to the following ten years, 1986-1997, when the number of T. infestans dropped drastically and that of T. rubrovaria increased. There are no consistent indications of intradomiciliary colonization by T. rubrovaria, since only low numbers of nymphs have been captured in the intradomiciliary ecotopes. Nevertheless, this species appears to have preadaptive characteristics for anthropic ecotopes, and should be kept under constant epidemiological surveillance.

Animals↗
PubMed2000

The taxonomy of Brazilian insects vectors of transmissible diseases (1900-2000)--then and now.

A brief historical overview is given of the most relevant taxonomic studies of insect groups vectors of transmissible diseases in Brazil, from the "heroic" times of the foundation of the Instituto Oswaldo Cruz in Rio de Janeiro up to the present. The following orders are considered: Phthiraptera (Anoplura, Amblycera and Ischnocera), Hemiptera (Reduviidae: Triatominae), Siphonaptera and Diptera (Culicidae, Ceratopogonidae, Psychodidae: Phlebotominae, Simuliidae, Tabanidae, Chloropidae and Muscidae). The most important Brazilian collections of each group are cited.

Academies and Institutes↗
PubMed2001

Experimental transmission of Trypanosoma cruzi through the genitalia of albino mice.

Trypanosoma cruzi is usually transmitted by contact with the excreta of infected Triatominae; among non-vectorial infections, direct transmission through coitus has been proposed. We investigated this possibility by instilling, through the external meatus of the vagina and the penis of previously anesthetized NMRI albino mice, blood of mice infected with strains isolated from Didelphis marsupialis (opossum, strain CO57), Rattus rattus (rat, strain CO22) and human (strain EP). Some animals were allowed to copulate the same day of the instillation. In other experiments, the strains were inoculated in the scrotum. To determine the effect of immunosuppression, some mice were treated with cyclophosphamide 30 days post-instillation. Controls were instilled orally and ocularly. Vaginal instillation with strain CO22 produced systemic infection with tropism to the heart, skeletal muscle, skin, duodenum, pancreas, ovary and sternum. Scrotal inoculation with strain EP likewise invaded liver, spleen, lung, lymph nodes and urogenital organs; while strain CO57 invaded skeletal and cardiac muscle, pancreas, testis, and vas deferens. Penile infection with strain CO22 was detected by xenodiagnosis. Immunosuppression did not increase parasitemia of vaginally infected mice or controls. Mating did not produce infection. Our results show that contact of blood trypomastigotes of T. cruzi with genital mucosa can produce blood and tissue infections. These results are discussed in relation to reports of frequent experimental tropism of T. cruzi toward urogenital organs.

Animals↗
PubMed2002

Aggregation mediated by faeces and footprints in Triatoma pseudomaculata (Heteroptera: Reduviidae), a Chagas disease vector.

The behavioural response of Triatoma pseudomaculata to chemical substances present in their faeces or cuticle (footprints) was analyzed. Groups of larvae were simultaneously exposed to a clean filter paper and to another paper impregnated with a chemical stimulus in a circular arena. In these choice experiments, the insects aggregated significantly around papers impregnated with dry faeces. In addition, the bugs also showed a significant aggregation response to papers impregnated with compounds derived from their cuticle that were deposited by contact on the substrate. These results indicate that chemical compounds that affect the behaviour of T. pseudomaculata are present in the faeces and in the cuticle of this species. Results are discussed in relation to chemical communication in the Triatominae, as well as to the potential use of these substances in traps or sensors for the detection of this species.

Animal Communication↗
PubMed2002

Comparative ultrastructural analysis of the antennae of Triatoma guazu and Triatoma jurbergi (Hemiptera: Reduviidae) during the nymphal stage development.

The specific concept of two triatominae species of epidemiological importance in the Mato Grosso Region (Brasil), Triatoma guazu Lent & Wygodzinsky, 1979 and Triatoma jurbergi Carcavallo, Galvão & Lent, 1998, the antenniferous tubercle and the four antennal segments of nymphs from the first to fifth instar were morphologically compared by scanning electron microscopy. The main differences observed were that the antenniferous tubercle in T. guazu did not present a smaller tubercle in the base of the larger tubercle. The first antennal segment in the fifth instar had sensilla distributed with an alternating array and the trichobothria in the first instar had half of its length reaching the third antennal segment. However, in T. jurbergi the antenniferous tubercle had two smaller tubercles in the base of the two larger tubercles. The first antennal segment in the fifth instar presents sensilla distributed in pairs, and the trichobothria in the first instar has only a small portion of the structure reaching the third antennal segment. These structures differentiated the nymphs of T. guazu and T. jurbergi.

Animals↗
PubMed2002

Immunotherapy of Trypanosoma cruzi infections.

The protozoan parasite Trypanosoma cruzi, causative agent of Chagas' disease, is transmitted to man and other mammals by triatominae insects, or 'kissing bugs'. Since its discovery in 1909, by Carlos Chagas, this parasite has been the object of several publications in the domains of immunology, cellular biology and of control gene organization, regulation and expression. Although much progress has been made concerning prophylaxis of Chagas' disease, particularly vector eradication, additional cases of infection and disease development still occur every day throughout the world. Whilst infection was largely limited in the past to vector transmission in endemic areas of Latin America, its impact has increased in terms of congenital and blood transmission, transplants and recrudescence following immunosuppressive states. Reports on new insect vectors adapted to the parasite and domestic animals infected in more developed countries, emphasize the continuing worldwide public health issue. Therapy against this parasite is limited and cure is subjected to several criteria, such as susceptibility of the parasite strain, age of the host and stage of the disease. The ability of Trypanosoma cruzi to induce important and various host immune system dysfunctions makes the development of effective vaccines a laborious and complex task. These considerations strengthen the latent significance of Chagas' disease and encourage the search for new preventive procedures and the research on rational vaccines.

Animals↗
PubMed2005

Development of Triatoma rubida sonoriana, Triatoma barberi, and Meccus mazzottii (Heteroptera, Reduviidae) under laboratory conditions.

The objective of this study was to determine some of the most important bionomic parameters related to the capacity of transmission of Trypanosoma cruzi and to estimate the potential transmission capacity and role of 3 groups of recent colonized Mexican Triatoma barberi, T. rubida sonoriana, and Meccus (formerly Triatoma) mazzottii in the prevalence of Chagas disease cases based on the distribution area of each species. Among the studied Triatominae species, the life cycle was shorter in T. r. sonoriana and longer in T. barberi, by as much as 4 times. The 1st and 5th instars had the highest rates of mortality in most of the studied species. Statistically significant shorter duration of feeding of instars was observed for T. r. sonoriana and longer duration was found for M. mazzottii when the species were compared. The mean number of blood meals per nymphal stadium was statistically greater in T. barberi than in T. r. sonoriana and M. mazzottii. Triatoma r. sonoriana and M. mazzotti had shorter defecation delay than in T. barberi and the delay was uniform in all instars. Most of the studied parameters showed that T. r. sonoriana and M. mazzotti could have an important potential role in the prevalence of Chagas disease cases where these species are commonly found.

Animals↗
PubMed2002

Ecologic niche modeling and potential reservoirs for Chagas disease, Mexico.

Ecologic niche modeling may improve our understanding of epidemiologically relevant vector and parasite-reservoir distributions. We used this tool to identify host relationships of Triatoma species implicated in transmission of Chagas disease. Associations have been documented between the protracta complex (Triatoma: Triatominae: Reduviidae) with packrat species (Neotoma spp.), providing an excellent case study for the broader challenge of developing hypotheses of association. Species pairs that were identified coincided exactly with those in previous studies, suggesting that local interactions between Triatoma and Neotoma species and subspecies have implications at a geographic level. Nothing is known about sylvatic associates of T. barberi, which are considered the primary Chagas vector in Mexico; its geographic distribution coincided closely with that of N. mexicana, suggesting interaction. The presence of this species was confirmed in two regions where it had been predicted but not previously collected. This approach may help in identifying Chagas disease risk areas, planning vector-control strategies, and exploring parasite-reservoir associations for other emerging diseases.

Animals↗
PubMed2006

[First finding of Chagas disease vectors associated with wild bushes in the Metropolitan Region of Chile].

BACKGROUND: Insects of the subfamily triatominae are the biological vectors of Trypanosoma cruzi, the causal agent of Chagas disease. AIM: To search for wild colonies of triatomines in the Metropolitan Region of Chile. MATERIAL AND METHODS: Ad hoc traps were placed in two endemic zones of the Metropolitan Region of Chile, during 30 nights. The dejections of 16 T infestans and 43 M spinolai specimens were examined under the microscope, searching for live metacyclic trypomastigotes. A polymerase chain reaction (PCR) was performed in macerates of all insects looking for T cruzi DNA. RESULTS: A total of 269 bugs were captured. Forty four were Triatoma infestans and 225 were Mepraia spinolai. They were not syntopic, since T infestans was restricted to a Southern zone (Calera de Tango) while M spinolai was only found in the Northern zone (Til-Til). Both species were found associated to terrestrial bromeliads (Puya sp) but M spinolai was also detected in stony grounds. Microscopic examination of dejections yielded a trypano-triatomine index of 56.3 and 32.6 for T infestans and M spinolai, respectively. PCR detected T cruzi DNA in 41 and 43% of T infestans and M spinolai specimens, respectively. CONCLUSIONS: The finding of T infestans in a wild habitat is noticeable. This is the first report of such phenomenon in Chile. The high infection rates with T cruzi, explains the maintenance of Chagas disease wild cycle in Chile.

Animals↗
PubMed1978

Biochemical characterization of some species of Trypansoma (Schizotrypanum) from bats (Microchiroptera).

Trypanosoma (Schizotryanum) species isolated from bats (Microchirotera) in Europe and Latin America were examined by determining the buoyant densities of their nuclear and kinetoplastic deoxyribonucleic acid (DNA) and the electrophoretic patterns of six isoenzymes. By these criteria they were separated into three distinct groups -- two from Europe (T. dionisii and T. vespertilionis) and one from America. T. dionisii was also separable by its morphology in vitro. Geographical location and DNA buoyant densities suggested that the American stocks were more closely related to T. cruzi than to the European species, though they differed from it marginally in kinetoplastic DNA density and in being noninfective to mice. Similar stocks studied by other workers have been shown to differ from T. cruzi also in reduced infectivity to, and lack of natural association with, Triatominae, and in antigenic composition. It is therefore proposed that trypanosomes of the subgenus Schizotryanum occuring naturally in Microchiroptera and differing from T. cruzi sensu stricto as outlined above should be treated as a distinct subspecies, T. cruzi marinkellei ssp. nov. T. cruzi sensu stricto thus becomes the nominate subspecies T. cruzi cruze Chagas 1909.

Alanine Transaminase↗
PubMed1989

Biological characterization of a strain of Trypanosoma cruzi chagas isolated from a human case of trypanosomiasis in California.

In August 1982, the first autochthonous case of human American trypanosomiasis in California occurred. The isolate, the Tuolumne strain of Trypanosoma, was infective to young laboratory mice and capable of causing death or chronic disease in these animals. The morphology and mensural characteristics are described. This strain can develop in 2 species of Triatominae native to California, Triatoma protracta and T. rubida. The flagellates isolated from these insects were infective to vertebrate hosts. Rhodnius prolixus, a neotropical species, was not susceptible to infection.

Animals↗