Chagas' disease in Aboriginal and Creole communities from the Gran Chaco Region of Argentina: Seroprevalence and molecular parasitological characterization.

Most indigenous ethnias from Northern Argentina live in rural areas of "the Gran Chaco" region, where Trypanosoma cruzi is endemic. Serological and parasitological features have been poorly characterized in Aboriginal populations and scarce information exist regarding relevant T. cruzi discrete typing units (DTU) and parasitic loads. This study was focused to characterize T. cruzi infection in Qom, Mocoit, Pit'laxá and Wichi ethnias (N=604) and Creole communities (N=257) inhabiting rural villages from two highly endemic provinces of the Argentinean Gran Chaco. DNA extracted using Hexadecyltrimethyl Ammonium Bromide reagent from peripheral blood samples was used for conventional PCR targeted to parasite kinetoplastid DNA (kDNA) and identification of DTUs using nuclear genomic markers. In kDNA-PCR positive samples from three rural Aboriginal communities of "Monte Impenetrable Chaqueño", minicircle signatures were characterized by Low stringency single primer-PCR and parasitic loads calculated using Real-Time PCR. Seroprevalence was higher in Aboriginal (47.98%) than in Creole (27.23%) rural communities (Chi square, p=4.e(-8)). A low seroprevalence (4.3%) was detected in a Qom settlement at the suburbs of Resistencia city (Fisher Exact test, p=2.e(-21)).The kDNA-PCR positivity was 42.15% in Aboriginal communities and 65.71% in Creole populations (Chi square, p=5.e(-4)). Among Aboriginal communities kDNA-PCR positivity was heterogeneous (Chi square, p=1.e(-4)). Highest kDNA-PCR positivity (79%) was detected in the Qom community of Colonia Aborigen and the lowest PCR positivity in two different surveys at the Wichi community of Misión Nueva Pompeya (33.3% in 2010 and 20.8% in 2014). TcV (or TcII/V/VI) was predominant in both Aboriginal and Creole communities, in agreement with DTU distribution reported for the region. Besides, two subjects were infected with TcVI, one with TcI and four presented mixed infections of TcV plus TcII/VI. Most minicircle signatures clustered according to their original localities, but in a few cases, signatures from one locality clustered with signatures from other village, suggesting circulation of the same strains in the area. Parasitic loads ranged from undetectable to around 50 parasite equivalents/mL, showing higher values than those generally observed in chronic Chagas disease patients living in urban centers of Argentina. Our findings reveal the persistence of high levels of infection in these neglected populations.

Trypanosoma cruzi discrete typing units in Chagas disease patients from endemic and non-endemic regions of Argentina.

Genetic diversity of Trypanosoma cruzi may play a role in pathogenesis of Chagas disease forms. Natural populations are classified into 6 Discrete Typing Units (DTUs) Tc I-VI with taxonomical status. This study aimed to identify T. cruzi DTUs in bloodstream and tissue samples of Argentinean patients with Chagas disease. PCR-based strategies allowed DTU identification in 256 clinical samples from 239 Argentinean patients. Tc V prevailed in blood from both asymptomatic and symptomatic cases and Tc I was more frequent in bloodstream, cardiac tissues and chagoma samples from immunosuppressed patients. Tc II and VI were identified in a minority of cases, while Tc III and Tc IV were not detected in the studied population. Interestingly, Tc I and Tc II/VI sequences were amplified from the same skin biopsy slice from a kidney transplant patient suffering Chagas disease reactivation. Further data also revealed the occurrence of mixed DTU populations in the human chronic infection. In conclusion, our findings provide evidence of the complexity of the dynamics of T. cruzi diversity in the natural history of human Chagas disease and allege the pathogenic role of DTUs I, II, V and VI in the studied population.

Differential detection of Blastocrithidia triatomae and Trypanosoma cruzi by amplification of 24salpha ribosomal RNA genes in faeces of sylvatic triatomine species from rural northwestern Argentina.

Flagellates indistinguishable from Trypanosoma cruzi were detected by microscopy in faecal samples of 2/110 Triatoma guasayana and 2/283 Triatoma garciabesi captured in a rural area of northwestern Argentina. Inoculation of faecal homogenates to mice followed by xenodiagnosis, haemoculture, histopathology and culture from cardiac homogenates, and PCR based on T. cruzi minicircle and nuclear sequences failed to detect T. cruzi infection, pointing to another trypanosomatidean. A PCR strategy targeted to the D7 domain of 24salpha ribosomal DNA genes amplified a 250 bp sequence from one T. guasayana and one T. garciabesi faecal lysate. Sequence analysis revealed 100% identity with 24salpha rDNA amplicons from Blastocrithidia triatomae obtained from faeces of reared Triatoma infestans bugs. Phylogenetic analysis clustered this sequence with C. fasciculata and L. major, separated from the Trypanosoma branch (bootstrap: 968/1000), in concordance with a Neighbour-joining dendrogram based on 18s rDNA sequences. This PCR procedure provides a rapid sensitive tool for differential diagnosis of morphologically similar trypanosomatids in field surveys of Chagas disease vectors and laboratory-reared triatomines used for xenodiagnosis.

[Access to the rectum via a posterior route and via a combined abdominal-posterior route: when and why]. / L'accesso al retto per via posteriore e per via combinata addomino-posteriore: quando e perché.

The authors report their experience of the posterior rectal access route. They used this route to operate 7 patients with rectal carcinoma during the period February 1989-October 1994; 3 patients were affected by villous adenoma, 3 by adenocarcinoma, and 1 by pelvic recidivation. Of the 3 patients suffering from adenocarcinoma, two underwent palliative treatment owing to their poor general conditions and the systemic nature of the base pathology, consisting in the exeresis of the tumour using a posterior route. The third patient was treated using a combined abdominal-posterior route; the site of the tumour and the presence of a narrow pelvis would in fact have made an "ultra low" front resection highly risky, whereas coloanal anastomosis (pull through) might have jeopardized efficacious anal continence. On the basis of their experience the authors indicate the posterior access route as a therapeutic possibility in the treatment of medium-low rectal tumours at an early or very advanced stage. The posterior approach is only justified in other forms if combined with laparotomic access. An oncologically correct operation is therefore guaranteed in full respect of sphincteric function.

[Hepatic amebiasis. Apropos of two cases]. / L'amebiasi epatica. A proposito di due casi.

The authors report 2 cases of amebic hepatic abscess, through to their observation with a little interval of time one from another and both coming from the same small town. Transmission modalities, the diagnostic approach and the therapeutic possibilities are discussed on the basis of personal experience.

[Malignant tumors of the pancreas and periampullary area. Our experience]. / I tumori maligni del pancreas e dell'area periampollare.

The authors analyse and evaluate the clinical records of 45 patients treated in the last 4 years for pancreatic cancer and neoplasm of the bilioduodenapancreatic area, comparing the results with data available in the literature. In the group of patients treated with resection (12 cases), postoperative morbidity and mortality were respectively 28% and 6%, and three-years survival was 22%. The authors discuss particularly about reconstruction ways after duodenopancreatectomy, showing good results after reconstruction by Y loop sec. Roux and pancreato-jejunal anastomosis.

[Axillo-femoral bypass in the treatment of aorta prosthesis infection. A special case]. / Il by-pass axillo-femorale nel trattamento di protesi aortica infetta. Un caso particolare.

The authors report a case recently brought to their observation: T.A., a 77 year old patient, operated on in July 1990, for aortic aneurysm with axillo femoral by-pass. The patient was reoperated on the 5th day for ischaemic necrosis of the descending colon. In 1992 he was operated in another hospital for right iliac branch removal of the by-pass and performing of extra-anatomic bifemoral by-pass for right iliac branch infection of anatomic prosthesis. He was brought to our observation in March 1993, after the patient was refused in other Centres because of purulent abscess located near the aortic prosthesis and in the right iliac fossa, with a fistula to right superior anterior iliac crista. The patient was operated on in April 1993, with an explorative laparatomy to drain the abscess and to remove the aortic prosthesis. The aorta was sutured with closed bottom by means of delayed points. The postoperative course was regular and an arteriography performed three months after confirms the good running of the axillo-femoral by-pass and of the bifemoral one previously performed. The authors because of their experience and the bibliographical data underline the goodness of the axillo-femoral by-pass in serious infections of an aortic prosthesis.

[Treatment of inguinal hernia in local anesthesia: our experience with the Shouldice surgical technique]. / Trattamento delle ernie inguinale in anestesia locale: nostra esperienza della plastica sec. Shouldice.

The authors present their personal experience in the surgical treatment of 256 cases of patients suffering from inguinal hernia, using the Shouldice technique in local anaesthesia. Minor incidence intra and postoperative complications compared with other types of anaesthesia, the possibility to converse with the patient during the operation and if necessary to invite him to cough in order to exclude the presence of other associated hernias or to assay the robustness and the resistance of the plastic, minor frequency of relapses compared with other operating techniques (1.5% in the Shouldice against 3% of the Bassini), and last but not least the possibility of early discharge from hospital and more swift resumption of work, confirm the full validity of this hernial plastic surgery.

[The emergency treatment of perforated colonic diverticula]. / Trattamento d'urgenza dei diverticoli perforati del colon.

The authors report their experience of the treatment of 43 cases of perforated colonic diverticula. The operations were: 12 primary resections-anastomoses; 7 resections-anastomoses with protective colostomy; 2 operations of suture and drainage; 22 Hartmann's resections. The authors believe that Hartmann's resection is the operation of first choice in cases of diffuse or stercoraceous peritonitis. This operation another the removal of the sick part of intestines without exposing the patient to the possible complications of an operation "at risk", and allows a late recanalization destitute of risk: in our experience 13 cases of 22 (59%).

[The "emergency" treatment of celiac trunk obliteration diagnosed during duodenocephalopancreatectomy. A case report]. / Trattamento "d'urgenza" della obliterazione del tronco celiaco diagnosticata in corso di una duodenocefalopancreatectomia. Case report.

The authors report about a case of celiac axis obliteration, noticed during an operation of pancreaticoduodenectomy for pancreatic formation. The arterial flux of sovramesocolic district took place completely through the gastroduodenal artery. To complete the operation the authors were obliged to stop the circulation of the pancreaticoduodenal artery and to rivascular the common hepatic through bypass with aorta. The authors confirm the importance of arteriography for the study of expansive lesions of the pancreas, liable to surgical treatment as well to avoid treating urgently similar cases or due to anatomic variants.