The objective of this study was the evaluation of the genetic diversity found in HBV circulating among Venezuelan Amerindians and the general population in Colombia. Phylogenetic analysis of the S region in 194 isolates showed that genotype F is highly predominant in Colombia and Venezuela. This might be related to the genetic background of the population. F3 is the main subgenotype which circulates in both countries. Phylogenetic analysis of 61 complete genome sequences of HBV American genotypes confirms the presence of two genotypes F and H, and 4 F subgenotypes. In Venezuela, subgenotypes F1, F2, and F3 circulate in East and West Amerindians, while only F3 was found among South Amerindians. Japreira community derived from Yucpa Amerindians around 150 years ago. However, several Japreira HBV sequences were forming a clade that can be classified as subgenotype 2b, differing from Yucpa sequences that belong mainly to subgenotype F3. The apparent absence of correlation between the phylogenetic groupings of HBV isolates with the ethnical origin in aboriginal populations might be suggesting a recent origin of HBV American subgenotypes, or a genetic drift effect. J. Med. Virol. 80:20–26, 2008. © 2007 Wiley‐Liss, Inc.

The prevalence of hepatitis C virus (HCV) infection was evaluated in 227 hemodialysis patients from four units in Caracas, Venezuela, by using different second-and third-generation enzyme immunoassays (EIAs) and immunoblot assays. HCV antibodies were detected in 162 patients (71%) by the recombinant-based secondgeneration assays (Abbott and Ortho) and in 161 patients by the synthetic peptide-based EIA (UBI). Of the 162 HCV antibody-positive serum samples, 161 were confirmed to be positive by RIBA 3. HCV RNA was detected in 49 of 68 (72%) of the seropositive patients and in 5 of 21 (24%) of the seronegative ones. HCV RNA was not always correlated with an increase in alanine aminotransferase (ALT) levels. Among 20 patients positive for HCV RNA and for HCV antibodies (without any hepatitis B virus [HBV] marker), only 10 had elevated ALT levels. The possible interference of HBV for HCV replication was evaluated. No significant difference was found between the presence of HCV RNA and the presence of any HBV serological markers. The possible routes of transmission of HCV in hemodialysis patients are multiple, and some of them are still controversial. Of the HCV-positive patients, 30% received a blood transfusion, significantly more than the 15% found for the HCV-negative group. However, blood transfusions alone could not account for the high incidence observed in this group of patients (38% from 1994 to 1995). In conclusion, about one-quarter of the apparently non-HCVinfected patients were probably seroconverting, ALT may not be a useful indicator of HCV infection in hemodialysis patients, and nosocomial transmission of HCV may play a role in the spread of HCV in this group.

Abstract. The prevalence and importance of Cyclospora cayetanensis as an enteropathogen among 71 patients (22-45 years old) with acquired immunodeficiency syndrome (AIDS) and 132 children with diarrhea (0-12 years old) from Venezuela was assessed retrospectively. Two to three stool samples from each patient attending our parasitology laboratory for parasitologic and medical assistance were examined. For identification of the coccidium, modified Ziehl-Neelsen carbolfuchsin staining of formalin-ether stool concentrates was used, and for other intestinal parasites, iron-hematoxylin-stained smears and formalin-ether concentrates were examined. Cyclospora oocysts were found in seven (9.8%) of 71 AIDS patients and seven (5.3%) of 132 children with diarrhea. Other pathogenic parasites were present in most of the patients (9 of 14, 64.3%) shedding oocysts. Cyclosporiasis predominated in children 2-5 years of age with respect to those Յ one year of age (P Ͻ 0.05). The findings suggest that C. cayetanensis is common in diarrheal patients from Venezuela. However, the role of the parasite as the causal agent of diarrhea in these patients is uncertain.

Infection by hepatitis C virus (HCV)*, the aetiologic agent responsible for the majority of non-A-non-B posttransfusion hepatitis, is detected by assaying for antibodies against structural and nonstructural recombinant proteins or synthetic peptides. The aim of this study was to characterize the antibody reactivity of selected sera against antigenic peptides spanning immunodominant regions of the core, NS4 and NS5 HCV proteins. Reactivity to synthetic peptides was determined by enzyme immunoassay (EIA) for 11 selected sera from blood donors (good responders), for 27 selected sera from hemodialysis patients (poor responders), all positive for HCV antibodies (tested by different second and third-generation assays), and for 7 negative sera. Some peptides from the core and the NS4 region were widely recognized by the tested sera. Sera not reactive with core, NS4, or NS5 region by some immunoblot assays exhibited reactivity against peptides from these proteins. Autoimmune reactivity associated with HCV infection was evaluated by using a synthetic peptide derived from the GOR peptide; 8/11 HCV-positive sera were found reactive against this peptide. No correlation was found between reactivity to any of the peptides tested and the presence of HCV RNA in the serum or with HCV genotype. The EIA reactivity of peptides from the core region suggested a multideterminant antigenic structure, where reactivity of each epitope may be differentially affected by neighboring amino acids depending on individual sera. This situation was particularly evidenced in selected sera from poor responder specimens where a more restricted antibody response to core peptides was observed. Reactivity of sera from HCV-infected patients with synthetic peptides from the core, NS4, and NS5 regions indicated the presence of multiple linear epitopes (particularly in the core region) that may be used in a mixture for immunodiagnosis; however, the length and exact position of the synthetic peptides must be chosen carefully.

A survey of 447 Amerindians aged 1-69 years (mean age, 18.6 Ϯ 15.8 years) in 3 mountain and 1 lowland communities from Venezuela were studied to determine the seroprevalence of Toxoplasma gondii, the environmental risk factors for the infection, and how the process of acculturation may affect the transmission rate. Serum samples were tested for immunoglobulin G antibodies by a commercial indirect hemagglutination test. The overall prevalence of infection was 49.7% (222 of 447) and ranged 38.2-62.4%. A higher antibody rate was found in the lowland setting as compared with those from the mountain area (P Ͻ 0.001). The geometric mean titer in the overall population was 280.3. No age-antibody association was detected in the mountain communities, although a gradual increase in positivity with increasing age (P Ͻ 0.01) was observed in the lowland setting, reaching a peak of 83.3% in the oldest group. The results suggest that transmission by infective cat feces may play a predominant role in the spread of infection in this population. This study demonstrates the environmental Toxoplasma infection pressure in this sylvatic population and how transmission rate is facilitated by environmental changes produced by acculturation.