Gloria Rey

Hepatitis C virus seroprevalence in multi-transfused patients in Colombia

BACKGROUND Hepatitis C Virus (HCV) infection is a public health problem worldwide, with particular relevance in multi-transfused patients given that HCV is principally transmitted by exposure to infected blood. STUDY DESIGN Between February and September 2003 a cross-sectional study was carried out in four hospital centres in Bogotá and Medellin, Colombia, to determine the risk factors for HCV infection in 500 multi-transfused patients. RESULTS The study population was distributed in five groups: haemophilia, haemodyalsis, acute bleeding, ontological illnesses and sickle cell disease or thalassemia. Serum samples from patients were tested for HCV antibodies (Asxym, Abbott). An overall prevalence (9.0%; 95% confidence interval (CI): 6.4-11.6) (45/500) of HCV infection was found. Anti-HCV antibodies were detected in 32.2% of patients with haemophilia, 6.1% of patients undergoing haemodialysis, 7.1% of patients with sickle cell disease or thalassemia, 2.6% of patients with acute bleeding and 3.4% of patients with ontological or hematological diseases. The main risk factors associated with infection by HCV were: to be hemophilic (odds ratio, OR = 18.03; 95% Cl: 3.96-114.17), having received transfusions before 1995 (OR = 12.27; 95% Cl: 5.57-27.69), and having received more than 48 units of blood components (OR = 6.08; 95% CI: 3.06-12.1). In the multivariate analysis, only the year of transfusions (before 1995) remained significantly associated with risk of infection by HCV. CONCLUSIONS The data show a 3-fold reduction in the infection risk between 1993 and 1995, when the serological screening for HCV in blood donors was being introduced. A reduction greater than 90% was achieved by 1995 when the screening coverage reached 99%.

Establishment and characterization of a new continuous cell line from Lutzomyia longipalpis (Diptera: Psychodidae) and its susceptibility to infections with arboviruses and Leishmania chagasi

Embryonic tissue explants of the sand fly Lutzomyia longipalpis (Lutz & Neiva 1912) the main vector of Leishmania chagasi (Cunha and Chagas), were used to obtain a continuous cell line (Lulo). The tissues were seeded in MM/VP12 medium and these were incubated at 28 masculineC. The first subculture was obtained 45 days after explanting and 96 passages have been made to date. Lulo is composed of epithelioid cells, showed a 0.04 generations/hour exponential growth rate and population doubling time at 24.7 h. The cell line isoenzymatic profiles were determined by using PGI, PGM, MPI and 6-PGDH systems, coinciding with patterns obtained from the same species and colonys pupae and adults. The species karyotype characteristics were recognized (2n = 8), in which pair 1 is subtelocentric and pairs 2, 3 and 4 are metacentric. Lulo was free from bacterial, fungal, mycoplasmic and viral infection. Susceptibility to five arbovirus was determined, the same as Lulo interaction with Leishmania promastigotes.

A new continuous cell line from the mosquito Psorophora confinnis (Diptera: Culicidae) and its susceptibility to infections with some arboviruses

A new cell line, PC-0199-BR, was established from embryonated eggs of the mosquito Psorophora confinnis. To date (September 2000) it has had 62 continuous passages. This is the first report of a cell line of mosquitoes belonging to the genus Psorophora. Cell growth initially was achieved in the MM/VP12 medium, supplemented with 20% fetal bovine serum; however, the subcultures were later adapted to Graces medium with 10% fetal bovine serum. Cell morphology in the primary cultures was heterogeneous; but later in the established cell line, the predominant cell type was epithelioid. Cultured cells were predominantly diploid (2n=6); however, chromosome abnormalities were observed in a small proportion of the cells in later passages. C and G band patterns were also determined in the karyotype. The cell line isozyme profiles coincided with pupae and adult samples of the species taken from the same colony. A preliminary arbovirus susceptibility study for the cell line was undertaken. No evidence was observed of contamination of the cell line with bacteria, fungi or mycoplasma.

Mortalidad asociada con las temporadas de mayor circulación de los virus de la influenza en Bogotá, Colombia, 1997-2005

OBJECTIVE To estimate potential excess mortality attributable to influenza viruses A and B and human respiratory syncytial virus (HRSV) during peak seasons of influenza virus circulation in Colombia from 1997 to 2005. METHODS A comparison of monthly, general mortality rates from pneumonia in children under 5 years of age and from pneumonia and cardiovascular disease in those more than 60 years of age in Bogota, Colombia, were compared to the citys peak seasons of influenza virus circulation. Mortality data were obtained from the National Bureau of Statistics of Colombia; peak seasons of virus circulation were defined as contiguous months in which the number of isolates was equal to or greater than half the total number of isolates for the year. Incidence rate ratios (IRR) and their 95% confidence intervals (95%CI) were determined. RESULTS Influenza A demonstrated a pattern of seasonal circulation, but influenza B and HRSV did not. The increased circulation of influenza virus was associated with an average annual increase of 5% in overall mortality during the study period (IRR = 1.05; 95%CI: 1.046-1.064). During seasons of increased circulation of influenza viruses, the combined mortality from pneumonia and influenza for all ages was 11% higher than it was at other times (IRR = 1.11; 95%CI: 1.051-1.178). CONCLUSIONS During peak seasons of influenza virus circulation in Colombia, there can be increased mortality, particularly from pneumonia and cardiovascular disease among those more than 60 years of age. Preventive actions specific to protecting against influenza should be taken, especially in these two age groups.

ESTABLISHMENT AND CHARACTERIZATION OF A CELL LINE FROM THE MOSQUITO ANOPHELES ALBIMANUS (DIPTERA : CULICIDAE)

A new cell line designated LSB-AA695BB, was established from embryos of the mosquito Anopheles albimanus. The primary culture was initiated in April, 1995, and the first passage was made 48 days later. Serial subcultures of the cells have been carried through 90 passage from Abril 1995 to February 1996. The cells were grown at 28 degrees C in MK/VP12 medium, supplemented with 20% fetal bovine serum: the pH tolerance ranged between 6.8 to 7.0. The cells have also been adapted to MM/VP12 medium under the same pH, temperature and serum concentration. The majority of the cells were a fibroblast-type. Isozyme characterization showed a pattern similar to that of An. albimanus pupae and adults but distinct from Ae. taeniorhynchus and Ae. albopictus (C6/36) mosquito cell lines. The culture was shown to be free of mycoplasma, bacteria and fungi. Microsporidia contamination of transovarial transmission was controlled with 6.0 micrograms/ml of albendazole.

Initiation of primary cell cultures from embryos of the mosquitoes Anopheles albimanus and Aedes taeniorhynchus (Diptera: Culicidae)

Primary cell cultures were obtained from eggs of Anopheles albimanus and Aedes taeniorhynchus mosquitoes, vectors of human malaria and of Venezuelan equine encephalitis virus, respectively. The cellular growth of the An. albimanus cells began four weeks after explanting the embryonic tissues in MK/VP12 medium, supplemented with 15% fetal bovine serum. The culture showed heterogeneous cellular morphology. With regard to the Ae. taeniorhynchus culture, growth occurred three weeks after initiating the culture in MM/VP12 medium. The majority of cells were small and round. Karyotypes were examined in the latter species.