The Afro-American Biomphalariae

The reports on the occurrence of African planorbids in South America and of South American species in Africa and Asia are reviewed.

Prevalence of hepatitis A virus infection in Afro-Brazilian isolated communities in Central Brazil

To investigate hepatitis A virus (HAV) infection rates among isolated African-descendant communities in Central Brazil, 947 subjects were interviewed about demographic characteristics in all 12 isolated Afro-descendant communities existing in the state of Mato Grosso do Sul, Central Brazil, between March 2002 and November 2003. Blood samples were collected and sera were tested for HAV antibodies (total and IgM anti-HAV) by enzyme-linked immunosorbent assay. The overall prevalence of HAV infection was 75.6% (95% CI: 72.7-78.3), ranging from 55.4 to 97.3%, depending on the communities studied. The prevalence of anti-HAV increased significantly with age, from 13.8% in the age 0-5 age group to 96.6% in those older than 40 years. The findings point out an intermediate endemicity of HAV infection in some Afro-Brazilian isolated communities in Central Brazil. In addition, the high proportion of susceptible young subjects could be target of future HAV vaccination programs.

In vitro anti-microbial activity of the Cuban medicinal plants Simarouba glauca DC, Melaleuca leucadendron L and Artemisia absinthium L

In the present study, an extensive in vitro antimicrobial profiling was performed for three medicinal plants grown in Cuba, namely Simarouba glauca, Melaleuca leucadendron and Artemisia absinthium. Ethanol extracts were tested for their antiprotozoal potential against Trypanosoma b. brucei, Trypanosoma cruzi, Leishmania infantum and Plasmodium falciparum. Antifungal activities were evaluated against Microsporum canis and Candida albicans whereas Escherichia coli and Staphylococcus aureus were used as test organisms for antibacterial activity. Cytotoxicity was assessed against human MRC-5 cells. Only M. leucadendron extract showed selective activity against microorganisms tested. Although S. glauca exhibited strong activity against all protozoa, it must be considered non-specific. The value of integrated evaluation of extracts with particular reference to selectivity is discussed.

Helicobacter pylori cagA and vacA genotypes in Cuban and Venezuelan populations

The aim of this study was to determine the presence of Helicobacter pylori cytotoxin-associated gene (cagA)/vacuolating cytotoxin gene (vacA) among patients with chronic gastritis in Cuba and Venezuela. Gastric antrum biopsies were taken for culture, DNA extraction and PCR analysis. Amplification of vacA and cagA segments was performed using two regions of cagA: 349 bp were amplified with the F1/B1 primers and the remaining 335 bp were amplified with the B7629/B7628 primers. The VA1-F/VA1-R set of primers was used to amplify the 259-bp (s1) or 286-bp (s2) product and the VAG-R/VAG-F set of primers was used to amplify the 567-bp (m1) or 642-bp (m2) regions of vacA. cagA was detected in 87% of the antral samples from Cuban patients and 80.3% of those from Venezuelan patients. All possible combinations of vacA regions were found, with the exception of s2/m1. The predominant combination found in both countries was s1/m1. The percentage of cagA+ strains was increased by the use of a second set of primers and a greater number of strains was amplified with the B7629/B7628 primers in the Cuban patients (p = 0.0001). There was no significant difference between the presence of the allelic variants of vacA and cagA in both populations. The predominant genotype was cagA+/s1m1 in both countries. The results support the necessary investigation of isolates circulating among the human population in each region.

In vitro antimicrobial assessment of Cuban propolis extracts

Propolis is a resinous mixture of different plant exudates collected by honeybees. Currently, propolis is widely used as a food supplement and in folk medicine. We have evaluated 20 Cuban propolis extracts of different chemical types, brown (BCP), red and yellow (YCP), with respect to their in vitro antibacterial, antifungal and antiprotozoal properties. The extracts inhibited the growth of Staphylococcus aureus and Trichophyton rubrum at low µg/mL concentrations, whereas they were not active against Escherichia coli and Candida albicans. The major activity of the extracts was found against the protozoa Leishmania, Trypanosoma and Plasmodium, although cytotoxicity against MRC-5 cells was also observed. The BCP-3, YCP-39 and YCP-60 extracts showed the highest activity against P. falciparum, with 50% of microbial growth (IC50) values of 0.2 µg/mL. A positive correlation between the biological activity and the chemical composition was observed for YCP extracts. The most promising antimicrobial activity corresponds to YCP subtype B, which contains acetyl triterpenes as the main constituents. The present in vitro study highlights the potential of propolis against protozoa, but further research is needed to increase selectivity towards the parasite. The observed chemical composition-activity relationship of propolis can contribute to the identification of the active principles and standardisation of this bee product.