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M C Contreras

Publications and source records attributed to M C Contreras.

At least 37 records · Page 2Linked to original sources
PubMedDate not supplied

[Results of serological reactions in patients with presumptive diagnosis of toxoplasmosis].

Even though Toxoplasma gondii is an ubiquitous parasite that can effect most of human structures and organs, not all clinical manifestations suggestive of being produced by it are caused by this protozoon. For these reasons sera samples of patients suspected of having toxoplasmosis are sent to the laboratory for detecting specific antibodies which would facilitate the differential diagnosis. Thus, 716 sera from suspected patients, mainly from the Metropolitan Region of Chile, were sent to the Parasitology Laboratory of Chile University in order to carry out in them, specific serological tests for toxoplasmosis: indirect hemagglutination test (IHAT), Sabin Feldman reaction (SFT) and complement fixation test (CFT). Were considered positive: IHAT and/or SFT with titers > or = 1:16 and CFT with titer > or = 1:5. The pathologies for demanding these serological tests were obstetrical problems 210 (29.3%), congenital problems 193 (27.0%), ophthalmopathies 81 (11.3%), adenopathies 77 (10.8%), AIDS 67 (9.4%), myocardiopathies 46 (6.4%) and miscellaneous 42 (5.9%). The positivity found in these sera was higher in ophthalmopathies (61.7%), followed by obstetrical problems, miscellaneous problems, myocardiopathies and AIDS (50.7-52.4%), less frequent was the positivity in adenopathies (35.1%) and congenital problems (23.1%). In general, the 43.7% of positivity for toxoplasmosis found in these patients is higher than the 37.0% found in the general population. High titers of IHAT and SFT plus positive CFT was found in 13-fold higher proportion than in the general population.

Adolescent↗
PubMedDate not supplied

[Immunodiagnosis of human parasitosis. I. Overview].

Various methods with either cellular or humoral basis employed in the diagnosis of human parasitoses are reviewed. Using different methods and techniques humoral antibodies have been increasingly detected. Recently antigen research is becoming important, either in the acute phase of infection or in the immunocompromised host.

Humans↗
PubMedDate not supplied

[Epidemiology of toxoplasmosis in Chile. VI. Prevalence of human infection, investigated by means of an indirect hemagglutination test, in regions VII, VIII and IX].

In presecuting the investigations on the epidemiology of toxoplasmosis in Chile, a new series of serological surveys has been performed during 1982-1989 in 10 urban and 25 periurban-rural localities from the regions VII, VIII and IX of the country (34 degrees 41'-39 degrees 38' South lat.). In 9,758, randomly selected apparently healthy persons, and indirect hemagglutination test (IHAT) for toxoplasmosis was carried out. The age of these individuals (4,203 males and 5,555 females) varied between 4 and 84 years. The examined persons represent a 0.33% of the total population of the three studied regions. IHAT titers of 1: > or = 16 were regarded as positive. The global prevalence for positive IHAT was 45.5% (50.5% in men and 41.7% in women). A higher proportion of positive tests was observed in urban areas (47.0%) than in periurban-rural sections (33.3%). An increasing prevalence with age was also observed. Only 5 (0.05%) persons had IHAT titers higher than 1:1000.

Adolescent↗
PubMedDate not supplied

[Seroepidemiological study of human hydatidosis, by means of an indirect hemagglutination test in Rio Negro County, X Region, Chile, 1989-1990].

Rio Negro Country (40 degrees 48'-40 degrees 50' South lat.; 73 degrees 12'-73 degrees 13' West long.), is located in the province of Osorno, South of Chile. It has a population of 18,031 inhabitants, with 39% in rural areas. The basic economic activity is cattle raising (cows, pigs). According to reports, prevalence of human hydatidosis in 1988 was 11.1 per 100,000. In order to contribute to a better knowledge of human hydatidosis in Rio Negro County, an indirect hemagglutination test (IHAT) was performed to 509 randomized persons. Five (1.0%) individuals resulted positive.

Adolescent↗
PubMedDate not supplied

[Comparison of the yield of indirect hemagglutination reaction and complement fixation reaction in the diagnosis of neurocysticercosis].

Two variations of an indirect hemagglutination test (IHAT) and a complement fixation test (CFT) for the diagnosis of human cysticercosis were compared and evaluated. For the IHAT, a cysticerci crude total saline extract (SE) and a cysticerci lyophylized and delipidized veronal bicarbonate saline buffer (VBS) extract were used, comparing their diagnosis yieldings with that of a CFT in 57 confirmed cysticercosis patients: 45 serum samples and 32 cerebrospinal fluid (CSF). Sera and CSF from 29 patients with other neurological diseases and 25 sera from healthy volunteers were also compared. Both types of methods presented an overall average concordance of 91.5% and 97.0% with CSF and sera respectively. With respect to the sensitivity observed with CFT was 85.2% and 93.3% for CSF and sera, whereas that of IHAT was 96.9% in CSF and 97.8% in sera, when SE antigen was used; with the VBS antigen for IHAT 96.9% and 95.6% were detected in CSF and sera respectively. In order to determine the specificity of the IHAT, besides the study in healthy volunteers, in patients with other neurological diseases and in 156 serum samples from individuals with other parasitoses, such as hydatidosis (43), trichinosis (56), fascioliasis (31) and Chagas' disease (26) were also tested. A high reactivity with the hydatidosis group was found. The specificity, using a titre > or = 1:16 as a diagnostic value and without considering hydatidic sera was 99.4% for RHAI (SE), 100.0% for RHAI (VBS). The use of IHAT and CFT in diagnosis of human cysticercosis is discussed.

Central Nervous System Diseases↗
PubMedDate not supplied

[Epidemiology of toxoplasmosis in Chile. VII. Prevalence of human infection investigated by means of indirect hemagglutination reaction in the regions X, XI and XII].

In pursuing the studies on the epidemiology of toxoplasmosis in Chile, a recent series of surveys have been undertaken in 1983-1990 in 4 urban and 22 periurban-rural localities from regions X, XI and XII of the country (39 degrees 38'-56 degrees 00' South lat.). An indirect hemagglutination test (IHAT) for toxoplasmosis was performed to 6,438 randomly selected apparently healthy persons. The age of the surveyed persons (2,779 males and 3,659 females) varied between 1 and 93 years. The number of examined persons represents a 0.61% of the total population of the three studied regions. IHAT titers of 1: > or = 16 were considered as positive. The general prevalence for positive IHAT was 46.3% (47.4% in men and 45.4% in women). Similarly to other regions, a higher proportion of positive reactors was detected in urban sections (49.0%) than in periurban-rural ones (40.3%). An increase of prevalence with age was also observed. Only 8 (0.12%) persons presented IHAT titers higher than 1:1000.

Adolescent↗
PubMedDate not supplied

[The indirect hemagglutination reaction in the diagnosis of trichinosis].

An indirect hemagglutination test (IHAT) for trichinosis using a Melcher's antigen was evaluated and compared with a precipitin test (PT) and a bentonite flocculation test (BFT). One hundred and forty eight serum samples from patients from the whole country confirmed or suspected to have trichinosis by clinical or epidemiological evidences were studied: 117 (79.1%) samples resulted positive by IHAT, 138 (93.2%) by PT and 65 (43.9%) by BFT. Sixty three serum samples from patients with strong clinical suspect of trichinosis presented the PT and the BFT positive and were compared with the IHAT for sensitivity study. IHAT was positive in 60 (95.2%) serum samples. In order to determine the specificity of IHAT 25 serum samples from healthy volunteers and 124 serum samples from individuals with other parasitoses, such as cysticercosis (48), hydatidosis (45) and fascioliasis (31) were studied. The specificity, using a titre > or = 1:16 as a possible diagnostic value was 96%. The use of IHAT with RP and BFT in the diagnosis of human trichinosis is discussed.

Complement Hemolytic Activity Assay↗
PubMedDate not supplied

[Problems related to the diagnosis of Chagas' disease].

Trypanosoma cruzi may be transmitted to a susceptible human through different routes: a superficial lesion in the skin, such as a scraping of the small wound produced by the hematophagous triatomid bug vector, which becomes infected with its contaminated feces; the placenta, from the infected mother to the product of conception; a transfusion from an infected donor, or even by ingestion of diverse foods infected or contaminated with the parasite. Whichever may be the transmission of the protozoon, it is advisable to have in mind that it is able to produce an asymptomatic or a symptomatic infection, being possible in both cases, using appropriated methods, to detect the T. cruzi and/or the antibodies generated. From the clinical stand-point, Chagas' Disease may present itself as acute or as a chronic disease. Habitually, the acute disease is characterized by general involvement, fever, hepato-splenomegaly, polidenopathy, and occasionally myocarditis and/or encephalitis, whereas, the chronic form of the disease is characterized by presenting itself in an isolated way or combined, chronic myocardiopathy, megaesophagous or megacolon. At any rate, the problems center in the possibility of a reasonable diagnostic assurance which permits the adoption of adequate therapeutic measures. Some facts, which may help to confront these problems are: a) The epidemiological antecedents (origin in an endemic area, personal knowledge of the vector or of being bitten by it, whether the mother or other relatives are affected by the disease, etc.).(ABSTRACT TRUNCATED AT 250 WORDS)

Chagas Disease↗
PubMedDate not supplied

[Epidemiology of toxoplasmosis in Chile. V. Prevalence of the infection in humans and domestic and wild animals, studied by indirect hemagglutination reaction, in the Juan Fernández Archipelago. V Region].

A serological study utilizing an indirect hemagglutination test (IHAT) for toxoplasmosis was carried out in 222 humans and in 58 domestic animals (31 dogs, Canis familiaris; 27 cats, Felis catus), and in 62 wild mammals distributed into 50 rabbits, Oryctolagus cuniculus and 12 goats, Capra hircus. This survey was performed in the Juan Fernández Archipelago, formed by three islands: Robinson Crusoe, Santa Clara and Alejandro Selkirk (80 degrees 47'-78 degrees 47' west long., and 33 degrees 36'-33 degrees 47' south lat.). Blood samples were collected in filter paper and IHAT with titres greater than or equal to 1:16 were considered positive. This survey showed a prevalence of 42.3% in humans with no difference between men (43.0%) and women (41.5%). A high prevalence was found within groups of young individuals (0 to 19 years old), men and women. Regarding the domestic animal population, 44.8% resulted positive, distributed as follows: dogs 9.7% and cats 85.2%. Twenty one percent of wild animals were positive, distributed as follows: rabbits 8.0% and goats 75.0%. The global prevalence of toxoplasmosis in animals (domestic and wild) was 32.5%. All titres in humans and animals were less than or equal to 1:512. Toxoplasmosis is well extended among the human and animal population of the Juan Fernández Archipelago.

Adolescent↗