Revista Cubana de Medicina Tropical最新文献

Introduction: fasciolosis is an endemic disease in cattle in Cuba and there is an increase in the number of reported human cases in recent years. The coproparasitological diagnosis of fasciolosis has low sensitivity and is hard-working; for that reason, it is important to use immunoenzymatic methods mainly those that can detect this parasite antigens in the feces. A system for antigen detection called FasciDIG, with a reported sensitivity of 10 ng/mL has been developed in "Pedro Kouri" Institute of Tropical Medicine.

Objective: to increase the sensitivity of FasciDIG through some modifications to this diagnostic method.

Methods: two foul dilutions (concentrations of antigen 1 000 ng/mL- 1.95ng/mL in H20 Tween-20) were evaluated in a simulated system using FasciDIG and modified FasciDIG. The FasciDiG was modified using the secondary antibody obtained from rabbit against excretory-secretory antigens of Fasciola hepatica combined with biotin and then adding commercial conjugated extravidine peroxidase. Feces were collected from the rectum of 96 animals for slaughter and were evaluated by both methods, FasciDig and modified FasciDig. Kappa index was calculated between both assays.

Results: the detection limit for the FasciDIG was 3.9 ng/mL whereas the modified FasciDIG detected up to 1.95 ng/mL. The agreement index calculated between the two tests was 0.6238 corresponding to an index of substantive or good agreement.

Conclusions: the modified method is more sensitive than FasciDIG and it can supplement the diagnosis of fasciolosis. The number of analyzed samples should be increased and the sensitivity and specificity should also be determined using the serial conic-cup sedimentation technique as the gold standard.

Introduction: the esterase enzymes have been defined as the mechanism of resistance to temephos in Aeges aegypti in Cuba, which is the most used larvacide worldwide.

Objective: to partially characterize the activity of esterases in exposed and nonexposed larvae at sublethal doses of temephos in an Aedes aegypti strain that is resistant to this product.

Methods: a susceptible reference Aedes aegypti strain (Rockefeller) and another temephos-resistant strain (SANtemFII) were used. The larvae from SANtemF11 strain were exposed to lethal concentration 90 (LC90) of temephos (1 ppm); 10 % of the surviving larvae after 24 hours (SANtem[24 h] was moved to clean water, with no exposure to insecticide for 24 hours (SANtem [48 h]). The activity of esterases was partially characterized in these larvae through biochemical assays and gel-polyacrylamide electrophoresis. The molecular weight of esterase A 4 (ESt. A4) was estimated with the support of sodium duodecyl sulophate (SDS-PAGE).

Results: the activity of esterases in SANtemF11 was significantly higher than in Rockefeller strain. Significant reduction of the activity of esterases in surviving larvae was observed (SANtemF11 [24 h], but it increased 24 h later without exposure to temephos. The zymogram showed that 10% of larvae that survived from temephos action, just the esterase A4 band increased if compared with those of SAntemF11. The estimated molecular weight of esterase A4 was 58 kDa.

Conclusions: the presence of a specific band of esterase (58 kDa) in surviving larvae confirmed the role of these enzymes in insecticidal resistance. The diagnosis of the function of the esterases in resistance to temephos through biochemical tests should not be made in larvae exposed to sublethal doses of this insecticide, in order to avoid false negatives.

Introduction: dengue and its lethal form, that is, dengue hemorrhagic fever, has significantly increased in Las Americas, being the Aedes aegypti the main and the only transmitting vector till now.

Objective: to evaluate the effectiveness of K-Othrine WG250 (deltamethrin) in residual (perifocal) applications in rest sites and in breeding sites of Aedes aegypti.

Methods: from February to June 2011, a perifocal residual treatment was applied in San Juan de Dios people's council of "José Martí" university polyclinic in Camaguey. It was directed to rest and breeding sites of the vector, for which several areas comprising different number of non-adjacent and randomly chosen houses, with high and similar rates of infestation in the period before the treatment, were selected. The application of this treatment was based on the use of IKA-9 hand sprayers at a dose of 1 g/l of water, with fitted conical nozzle for three areas and with flat nozzles 80-02 in the other three areas to deposit 25 mg ia/m2. Focality was monitored 5 months before the applications and 3 months afterwards by means of entomological surveys conducted in the selected universe of houses.

Results: the number of foci was reduced to 0 in the first month after the application if compared to the existing number before the treatment and with both types of nozzles. Fifteen positive reservoirs were reported in June, mainly low water tanks located outside the house.

Conclusions: this product showed high effectiveness for 3 months in the Aedes aegypti control as part of the residual (perifocal) treatment. Therefore, it should be considered as an alternative in the surveillance and control strategies aimed at this vector.

Introduction: Aedes aegypti is a common vector in Cuba, which damages human health. Santiago de Cuba is one of the provinces with high number of mosquito foci in a sustained way. Therefore, it is very important, from the social viewpoint, to carry out educational interventions with anti-vector campaign workers in Mella municipality in this province.

Objective: to evaluate the impact of an educational intervention on dengue, Aedes aegypti and monitoring actions with anti-vector program workers from Mella municipality in Santiago de Cuba.

Methods: a quasi-experimental research was conducted before and after the educational intervention from November to December, 2010. Lectures and workshops were given in each of the three health areas of the municipality. The sample was made up of 64 workers. The addressed topics were dengue, Aedes aegypti and actions to control them. An Excel database was created. Wilconxon's sign tests were applied to check changes in knowledge. SPSS statistical processor was used (11.5 version).

Results: before the educational interveption, the knowledge on dengue was broader than those on the rest of the addressed topics. After the intervention, except for the responses about the disease, the rest of the topics increased their initial assessment values. The topic Aedes aegypti had the highest number of satisfactory answers (100 %), followed by actions to control the vector (90 %).

Conclusions: the educational strategy was effective, since it achieved high impact on the increase of knowledge of the anti-vector campaign workers in Mella municipality, Santiago de Cuba province.

Introduction: During dengue epidemics in Cuba, an increase in clinical severity with the epidemics progression in time, particularly in secondary infections, have been frequently observed. It is considered that this increase could be related with genetic changes in the circulating virus.

Objective: To study some biological attributes related to strains isolated at different points of time during the dengue epidemic occurred in Havana city, 2001-2002.

Methods: Nine DENV-3 strains were studied. Cytopathogenic effect, viral growth in C6/36 HT and Vero cell lines, viral plaque sizes, temperature sensitivity, neurovirulence in newborn mice and pH influence in the binding of the virus and the cell as well as in the multiplication medium were evaluated.

Results: DENV-3 strains were more cytopathogenic in Vero Cells. However, higher titres were obtained in C6/36 HT cells. All the strains showed reduction of viral titres and plaque size with temperature increasing and low neurovirulence. Basic pH favoured virus-cell binding whereas acid pH was only permissive for some strains isolated at the end of the epidemic. On the other hand, at pH 6.5-7, the viral multiplication medium favoured the growth of strains isolated at the beginning of the epidemic whereas the growth of those isolated at the endof the epidemic was noticeable at pH 7-8.

Conclusions: This study proved the phenotypical changes among strains isolated at different points of time in the epidemic. They might be related to differences in viral fitness or in virulent potential. Nevertheless, some of the studied biological properties suggest that dengue virus-3 strains are less virulent than the Cuban dengue virus 2 strains isolated in 1997.

Objectives: To describe the variation and the trend of new tuberculosis case reports in Havana from 1995 to 2010, as well as their projection and occurrence for 2011-2013.

Methods: A time series study was conducted, and the annual total and mean variation percentages of rates by clinical and bacteriological categories, age, municipal distribution and TB/HIV co-infection were analyzed. Estimation of projections by using two-parameter exponential smoothing techniques was made.

Results: The rate of new reported TB cases decreased from 16.8 in 1995 to 9.5 per 100 000 inhabitants in 2010 (43.5% and 2.9% of annual total variation and mean variation respectively). The rate declined by 80% in the municipalities and in 15-64 and > or = 65 years age groups. Habana Vieja and Centro Habana municipalities kept the highest rates throughout the whole period. TB/HIV coinfection notification increased from 3 out of 369 (0.8%) cases in 1995 to 37 out of 202 (18.3%) cases in 2010. A slight increase was estimated for the 2011-2013 period (9.5; 10.0; 10.5 per 100 000 population respectively) in addition to continuous rise of the number of cases with TB/HIV co-infection.

Conclusions: The TB trend showed a steady decline in Havana from 1995 to 2010, with substantial reduction in the study period, except for TB/HIV co-infection in which the number of cases increases. The TB case report rates are within the expected values, although slightly above the predictions.

Introduction: Multiple drug resistant tuberculosis is an increasingly significant medical problem, because it means the spread of microorganisms for which "second line" drugs are required to eliminate them; therapeutic effectiveness is lower, it takes longer to treat it, leading to more adverse effects in addition to being more expensive than the conventional treatment.

Objective: To identify the response to individualized treatment in multiple drug resistant tuberculosis patients, who are non-HIV seropositive.

Method: A descriptive study was conducted in a sample of multiple drug resistant patients, who were treated for a year under individualized courses of treatment from 2000 to 2010 in Hospital Neumológico "Benéfico Jurídico". Data were collected from their medical histories and from bacteriological records.

Results: Out of 42 patients, 85.7% were males and the average age was 48.8 years. The most common category on admission was chronically-ill patient (40.5%). The average time for negative results in direct exam was 4.6 months and in culturing was 6 months; this indicator was lower in patients regarded as failures and higher in those classified as relapses. The highest healing percentage was found in chronic patients and in those classified as failures, accounting for 23.8 and 21.4% respectively.

Conclusions: The compliance with individualized treatment under direct observation in multiple drug resistant tuberculosis proved to be effective in over half of the cases.

Introduction: The frequent incidence of Enterococci at hospitals and their growing antimicrobial resistance worldwide make the in-hospital surveillance and control a pressing need; consequently, it is indispensable to avail of more sensitive and accurate diagnostic means.

Objective: To broaden the evaluation of functionality of CromoCen ENT chromogenic medium for the isolation and identification of Enterococcus spp. from clinical samples.

Methods: One hundred and fifty clinical samples were analyzed (urine, blood, feces, vaginal smears, skin lesion exudates and exudates from catheters) in the January-April period, 2010 by using the chromogenic medium and the corresponding conventional culture media as controls; the incidence of Enterococcus spp was evaluated. The isolations were identified with 12 biochemical tests. From the biochemical identification data, it was possible to determine the quality indicators for both CromoCen ENT and the reference media.

Results: The chromogenic medium encouraged the growth of Enterococcus species in 24 hours, allowing their easy recognition due to the pink coloration of the colonies. The diagnostic quality indicator values were over 95%. The highest percentage of isolates was observed in the urine samples. Enterococcus faecalis was the mostly found species.

Conclusions: CromoCen ENT allowed quick and accurate identification of Enterococcus spp. from various clinical samples.

Objective: To study the effect of water extraction and renewal on the residual action of temephos applied at 1ppm to cement water-storage containers at home.

Methods: The study was conducted in two stages: one, determination of the granular temephos effectiveness on wild Aedes aegypti populations in order to set the monitoring baseline; and second, the measurement of the mean rate of water extraction at home and its effect on the residual activity of temephos.

Results: The effectiveness of granular temephos was CL95 = 0.095 ppm (IC95%: 0.079-0.118). As average, it was found that 69.2% of water stored in cement containers was daily used and renewed, which means significant dilution. For the purpose of simplifying the experiments on residual activity, water was extracted and renewed at a rate of 50% every day for 2 weeks. It was found that temephos effectiveness significantly declined from day 7 on after application.

Conclusions: This rate of water extraction under study has an important effect on the residual activity of temephos. If this rate and the CL95 of granular temephos are considered in estimating the dosing, positive effects on the control of Aedes aegypti and more likely on the occurrence of resistance will be attained.