Isolation of Trypanosoma cruzi DNA in 4,000-year-old mummified human tissue from northern Chile

A segment of DNA unique to the kinetoplast of Trypanosoma cruzi was isolated from spontaneously mummified human remains from the coastal area of northern Chile at sites dated from 2000 BC to about AD 1400. Following rehydration of the desiccated human tissue samples of heart, esophagus, or colon, the samples were extracted and primers employed to bind to a 330 bp kinetoplast minicircle DNA sequence present in T. cruzi. This segment was then amplified using the polymerase chain reaction (PCR), and the target segment was visualized by gel electrophoresis. This method enables the identification of Chagas' disease in an ancient body in the absence of recognizable anatomic pathological changes.

Acute and one year follow-up results after vessel size adapted PTCA using intracoronary ultrasound

AIMS

Recent randomized clinical trials have reported a reduction in restenosis with intracoronary stents and have suggested that this restenosis reduction is a result of the higher immediate luminal gain, in comparison to conventional percutaneous transluminal coronary angioplasty (PTCA). The hypothesis of this study is based on the assumption that PTCA results may be optimized by determining vessel dimensions before intervention, using intravascular ultrasound. This may lead to long-term PTCA results equivalent to PTCA and the additional placement of a stent. The purpose of this prospective non-randomized single-centre study was to evaluate (1) the safety and efficacy and (2) the long-term outcome of vessel-size adapted PTCA in patients with native coronary artery obstructions.

METHODS AND RESULTS

From January 1995 to December 1995 the morphological dimensions of target lesions were determined in 144 patients with 152 lesions by intravascular ultrasound prior to conventional balloon angioplasty. Quantitative assessment of the vascular dimensions were assessed on-line and the diameter of the balloon catheter was adapted to the external elastic membrane diameter at the lesion site. Using this strategy, mean balloon diameter was 4.0 +/- 0.5 mm and mean pressure for complete balloon expansion was 7 +/- 2 atmospheres. Acute and one year follow-up results were obtained in all 144 patients. Acute events occurred in two patients (one death and one acute surgical revascularization). During one year follow-up, 16 patients (12%) had a clinical event including one cardiac death, two transmural myocardial infarctions, 10 repeat PTCAs within the target lesion and three elective coronary artery bypass grafts (CABG). In 75% (n:112) control angiography was performed and revealed an angiographic restenosis rate of 21% using the NHLBI criteria of a diameter stenosis > 50%.

CONCLUSION

Intravascular ultrasound provides an accurate and precise description of vascular dimensions at the site of the stenotic lesion. The use of balloon diameters following these measurements appears to be (1) safe in the acute setting with a low number of in hospital events and (2) gives a low restenosis rate and number of clinical events at one year follow-up. These promising results warrant verification in larger-scale randomized trials.

Auricular chromoblastomycosis caused by Rhinocladiella aquaspersa

An unusual case of chromoblastomycosis localized in the ear and caused by R. aquaspersa is presented. The patient was a 60-year-old male urban resident, who had had the disease for 5 years. The lesion was darkly pigmented, infiltrative and crusty. Sclerotic cells were seen on direct examinations and the fungus was recovered in culture and identified on the basis of the characteristic sporulation. Itraconazole therapy at a dose of 200 mg day-1 for 7 months produced complete healing.

Elastic structures in the vocalization apparatus of the Túngara frog Physalaemus pustulosus (Leptodactylidae)

Histological analysis of the vocal sac and body wall in the leptodactylid frog Physalaemus pustulosus suggests that both muscle and elastic fibers are important in call production. Abdominal musculature as well as abdominal bands of elastin (the lineae masculinae) provide the energy required for exhalation and sound production. Air flowing through the larynx inflates a highly extensible vocal sac lined with muscle and a network of elastic fibers. Inherent elasticity together with muscular activity of the vocal sac likely increase the speed and possibly decrease the energetic costs of lung reinflation following vocalization. The mechanics of call production in P. pustulosus thus involve not only laryngeal activation but also elastic transfer of air between the supralaryngeal vocal sac and abdominal respiratory structures.

Bionomics of Lutzomyia evansi (Diptera: Psychodidae) vector of visceral leishmaniasis in northern Columbia

The feeding behavior, seasonality, and natural infection rate of Lutzomyia evansi (Nuñez-Tovar) with Leishmania chagasi (Cuna & Chagas) was studied during a 12-mo period at 2 hamlets, El Contento and Vidales. Sand fly abundance in extra-, peri-, and intradomestic habitats was evaluated with sticky traps and CDC light traps, whereas human bait and Shannon trap collections were made only in peridomestic habitats. All trapping methods showed a clear predominance of L. evansi throughout the year. Sand flies were present during most of the year, with the exception of the driest months (February and March). Although the total number of sand flies was higher in El Contento than in Vidales, a larger proportion of L. evansi was found in intradomestic habitat than in the peri- and extradomestic habitats at Vidales. Also, sand flies from Vidales had a higher infection rate with L. chagasi than did those from El Contento. Although 2 of 9 promastigote infections detected in L. evansi were identified as L. chagasi, the difficulty of isolating and propagating leishmania strains from this visceral leishmaniasis focus precluded characterization of most parasite samples. Parous and infected sand flies were most abundant toward the end of the rainy season (October-December). For this reason, control strategies based on reducing sand fly populations or avoiding human-vector contact should be concentrated during the October-December period.

Phlebotomine sandflies associated with a focus of cutaneous leishmaniasis in Valle del Cauca, Colombia

A survey was made of the phlebotomine sandfly fauna of La Guaira, a village with coffee plantations near Cali, Colombia, from which cases of American cutaneous leishmaniasis had been reported due to Leishmania (Viannia) panamensis and Le. (V.) braziliensis. Among six species of sandfly collected on human bait, Lutzomyia youngi was most important in terms of biting nuisance. Lu.columbiana, Lu.lichyi and Lu.scorzai as well as Lu.youngi adults occurred throughout the year. Sandfly man-biting activity occurred throughout the night and was highest within 2 h of sunset. Despite its abundance in nocturnal samples, Lu.youngi was rarely taken in diurnal resting site collections. In contrast, Lu.lichyi was collected on tree-trunks during the day in large numbers and was the only species biting in daylight. The implications of these and other findings for leishmaniasis control measures in La Guaira are considered.

An attempt to control Phlebotomine sand flies (Diptera: Psychodidae) by residual spraying with deltamethrin in a Colombian village

An attempt was made to control phlebotomine sand flies biting indoors in a rural community near Cali, Colombia, using the residual insecticide "K-Othrine" (deltamethrin) sprayed on the inside walls of houses. Twelve houses were divided into matched pairs based on physical characteristics, one house in each pair being left untreated while the inside walls of the other were sprayed with 1% deltamethrin at a concentration of 500 mg a.i./m2. Sand flies were sampled each week using protected human bait and sticky trap collections for four months after spraying. The number of sand flies (Lutzomyia youngi) collected on sticky traps was significantly lower (P = 0.004) in the untreated houses than in the treated ones with which they were matched. This difference was not significant for L. columbiana; the other anthropophilic species were not present in large numbers. The numbers collected on human bait in treated and untreated houses were not significantly different for either species. Activity of the insecticide as determined by contact bioassays remained high throughout the study and failure to control the insects was attributed to two factors: the tendency of sand flies to bite before making contact with the insecticide and the fact that the number of sand flies that entered houses represented a relatively small proportion of the population in the wooded areas surrounding the settlement in the study.

Didelphis marsupialis, an important reservoir of Trypanosoma (Schizotrypanum) cruzi and Leishmania (Leishmania) chagasi in Colombia

The role of Didelphis marsupialis as a reservoir of zoonotic hemoflagellates was examined in two ecologically distinct settings in Colombia. While 72% (12 of 18) of the opossums collected in the tropical rain forest harbored Trypanosoma cruzi, other mammals in the area had lower infection rates: 1.3% (Proechymis semispinosus [spiny rat]; 13% Tylomys mirae [climbing rat]; and 6% Rattus rattus). Trypanosoma cruzi isolates from D. marsupialis were similar to zymodeme 1 (Z1), and two of four phenotypes were shared with Tylomys mirae, which is also predominantly arboreal. Terrestrial (P. semispinosus) and peridomestic (R. rattus) animals were infected with Z3 or other Z1 phenotypes, respectively. Schizodeme analysis showed polymorphisms among isolates from mammals, reflecting diverse modes of transmission, and a complex epidemiologic situation. Despite the lower infection rate of the opossum (14%) found in our study in the tropical dry forest as compared with the tropical wet forest, Chagas' disease has been reported only in the former area. This suggests that the lack of alternative blood sources for triatomines of the tropical dry forest, where mammals are less abundant than in the wet forest, may increase the risk of human infection. Among several species of mammals captured in the tropical dry forest, Leishmania chagasi was isolated from 22.7% (5 of 22) D. marsupialis. This finding confirms the important role of opossums in Colombian foci of visceral leishmaniasis, including those where the phlebotomine species involved in transmission is Lutzomyia evansi, an alternative vector to the more common Lutzomyia longipalpis.

Vector competence of some neotropical sandflies for the Leishmania (Viannia) braziliensis complex

To evaluate the vector competence of some Lutzomyia spp. (Diptera: Psychodidae) for Leishmania (Viannia) spp. (Kinetoplastida: Trypanosomatidae), experimental infections of anthropophilic sandflies from the Colombian Pacific coast were performed, through membrane feeding and xenodiagnosis on hamsters infected with Le. (V.)braziliensis or Le. (V.)panamensis. Wild-caught or F1 generation females of Lutzomyia gomezi, Lu. hartmanni, Lu.panamensis and Lu.trapidoi were allowed to feed on hamster lesions and then maintained at 26 degrees C and > 80% r.h. on a sugar-water diet until dissection on the fifth day post-infection (p.i.). Despite similar infection rates (range 37-44%) in both Lu.gomezi and Lu.trapidoi, infections were heavier (> 100 parasites) in the latter species. Infections of Lu.trapidoi with Le.braziliensis (n = 21) and Le.panamensis (n = 27) showed parasite migration toward the foregut, with promastigote colonization of the stomodeal valve and appearance of infective forms. In contrast, infections of Lu.gomezi with Le.braziliensis (n = 10) and Le.panamensis (n = 5) were light (< 50 parasites) and usually restricted to the pylorus. In Lu.hartmanni, only a few promastigotes were found in the pylorus and midgut of 3/8 specimens infected with Le.braziliensis, and no Le.panamensis developed (n = 19). By day 5 p.i., promastigote colonization of the hind- and midgut by Le.panamensis was observed in 2/4 Lu.panamensis but not Le.braziliensis (n = 3). It was concluded that Lu.trapidoi is a more efficient vector than Lu.gomezi for both Le.braziliensis and Le.panamensis, and that Lu.hartmanni and Lu.panamensis are of minor importance for Leishmania transmission in this endemic area.

A monoclonal antibody for distinction of invasive and noninvasive clinical isolates of Entamoeba histolytica

Approximately 10% of the world population is infected with Entamoeba histolytica, but only 10% of the carriers develop symptomatic amebiasis. This discrepancy could be explained by the genotypic differences between the morphologically indistinguishable invasive and noninvasive strains of E. histolytica currently identified by zymodeme analysis, a technique that is unsuitable for routine diagnostic laboratories. Here we report the production of a monoclonal antibody against E. histolytica and its use in an immunofluorescence assay to identify invasive isolates cultured from stool samples of infected patients in several regions where amebiasis is endemic: Bangladesh, Colombia, and Mexico. After testing a total of 88 E. histolytica isolates, the correlation between zymodeme characterization and the immunofluorescence assay with the invasive isolate-specific monoclonal antibody was 100%. The epitope detected by the invasive isolate-specific monoclonal antibody resides in a previously undescribed internal protein with molecular masses of 84 and 81 kDa in axenic and polyxenic E. histolytica strains, respectively.

Development of Mansonella perstans in the surrogate vector Aedes aegypti

The biology of the human filaria Mansonella perstans has been poorly studied due in part to the lack of experimental animal models in which its life-cycle could be reproduced. In nature Culicodes spp. (and probably simuliids) are the vectors involved in disease transmission. In the present work Aedes aegypti black-eyed strain was experimentally infected with M. perstans microfilariae by intrathoracic inoculation of 8 to 15 parasites contained in 0.4-0.6 microliters of RPMI 1640. Concentration of microfilariae was achieved by means of a ficoll separation technique. A. aegypti were maintained at 26 degrees C and 80% relative humidity with a sugar-water diet, except on day 4 post-infection on which they received an uninfected blood meal. Larval development was slow, taking no less than 4 days to reach the sausage stage, which measured 95-100 microns in length. Molt to the second stage took place on the 6th day; the differentiation into a long muscular and glandular esophagus, and short intestine measuring approximately one fourth of the total larval length were the most significant changes. At the end of this period 4 small but well demarcated tail papillae were observed. The first third-stage larvae appeared at the 8th day post-infection, measuring 650 to 680 microns in length. Beyond the 10th day larvae with an average length of 750 microns were found in the thorax, head, and mouthparts. Four conspicuous tail papillae characteristic of the genus Mansonella were seen in all third-stage larvae.(ABSTRACT TRUNCATED AT 250 WORDS)

Leishmaniasis in Colombia. I. Studies on the phlebotomine fauna associated with endemic foci in the Pacific Coast region

Studies on the phlebotomine fauna related to the leishmaniasis endemic foci of the Colombian Pacific Coast were carried out in the municipalities of Tumaco and Buenaventura. In Inguapí del Guadual, Tumaco, Lutzomyia trapidoi and Lu. gomezi were the predominant anthropophilic species; Lu. panamensis and Lu. hartmanni were less frequent. In Bajo Calima, Buenaventura, Lu. trapidoi represented over 94% of the anthropophilic sandflies. Continuous sampling from 1800 to 0600 hours in Inguapí del Guadual demonstrated that Lu. trapidoi bites mainly at dusk and dawn whereas Lu. gomezi remains active throughout the night. In Inguapí del Guadual, promastigotes were found in 0.1% (2/2, 305) of Lu. trapidoi, 0.2% (3/140) of Lu. gomezi, and 0.2% (1/424) of Lu. panamensis samples collected. In Bajo Calima, 1.9% (8/429) of Lu. trapidoi were found to be infected. Leishmania braziliensis panamensis, the most common Leishmania subspecies in the human population of this endemic focus, was isolated from 1 Lu. trapidoi from Inguapí del Guadual. Parasitological and entomological findings suggest that Lu. trapidoi could be the main vector of Leishmania in these areas, although Lu. gomezi and Lu. panamensis were also predominant.

Fragile-X mental retardation syndrome transmitted through intellectually normal males: implications for genetic counseling

The fragile-X mental retardation syndrome is the second most common identifiable cause of mental retardation in man. This condition violates many of the expectations for X-linked disorders, including the transmission of the syndrome through men who carry the gene but, for unknown reasons, do not express it. Two new cases of male transmission are presented along with four other cases heretofore unidentified in the literature, bringing the total number of confirmed or probable cases of transmission through normal men to 32. The various unorthodox characteristics of the syndrome are reviewed in light of their influence on genetic counseling. Recommendations for counseling families with fragile-X include evaluating all sons of carrier women psychometrically and cytogenetically, abandoning termination of pregnancies with male fetuses as a means of preventing the fragile-X syndrome, assuming that all mothers of sporadic cases are carriers, and karyotyping at-risk female members at an early age.

Antibody response to experimental Trypanosoma rangeli infection and its implications for immunodiagnosis of South American trypanosomiasis

Differential immunodiagnosis of T. rangeli and T. cruzi infections in man poses a particular problem, not only because these parasites share antigenic determinants, as detected by immunofluorescence, but also because they have a similar geographical distribution, the same host range and often identical insect vectors. We show here that whereas mouse anti-T. rangeli sera have significant cross reactivity with T. cruzi by immunofluorescence, they are entirely specific when tested by ELISA, using apparently similar antigen preparations. Immunoprecipitation analysis detected relatively little cross-reactivity between heterologous antisera and parasite combinations. Intriguingly, immunization with T. rangeli epimastigotes was much more powerful than similar immunization with trypomastigotes, and the majority of the antibody was directed against a single polypeptide of apparent Mr 73kDa.