Assessment of Therapeutic Response of Plasmodium vivax and Plasmodium falciparum to Chloroquine in a Malaria Transmission Free Area in Colombia

In order to determine the frequency of therapeutic failures to chloroquine (CQ) in patients with malaria due to either Plasmodium falciparum or P. vivax, and to explore the usefulness of a malaria-free city as a sentinel site to monitor the emergence of drug resistance, 53 patients (44 infected with P. vivax and 9 with P. falciparum) were evaluated at the Laboratory of Parasitology, Universidad del Valle in Cali, Colombia. Patients received 25 mg/kg of CQ divided in three doses over 48 h; they were followed during 28 days according to WHO/PAHO protocols. While therapeutic failures to CQ in the P. vivax group were not detected, the proportion of therapeutic failures in the P. falciparum group was high (78%) and consistent with the reports from endemic areas in Colombia. The diverse origin of cases presenting therapeutic failure confirmed that P. falciparum resistant to CQ is widespread in Colombia, and further supports the change in the national antimalarial drug scheme. Monitoring of drug resistance in malaria free areas would be useful to identify sites requiring efficacy evaluation, and in some situations could be the most appropriate alternative to collect information from endemic areas where therapeutic efficacy studies are not feasible.

Diphtheria remains a threat to health in the developing world: an overview

Changes in the epidemiology of diphtheria are occurring worldwide. A large proportion of adults in many industrialized and developing countries are now susceptible to diphtheria. Vaccine-induced immunity wanes over time unless periodic booster is given or exposure to toxigenic Corynebacterium diphtheriae occurs. Immunity gap in adults coupled with large numbers of susceptible children creates the potential for new extensive epidemics. Epidemic emergencies may not be long in coming in countries experiencing rapid industrialization or undergoing sociopolitical instability where many of the factors thought to be important in producing epidemic such as mass population movements and difficult hygienic and economic conditions are present. The continuous circulation of toxigenic C. diphtheriae emphasizes the need to be aware of epidemiological features, clinical signs, and symptoms of diphtheria in vaccine era so that cases can be promptly diagnosed and treated, and further public health measures can be taken to contain this serious disease. This overview focused on worldwide data obtained from diphtheria with particular emphasis to main factors leading to recent epidemics, new clinical forms of C. diphtheriae infections, expression of virulence factors, other than toxin production, control strategies, and laboratory diagnosis procedures.

Taeniasis-cysticercosis in Southern Ecuador: assessment of infection status using multiple laboratory diagnostic tools

Taenia solium-taeniasis and cysticercosis were studied in the human and porcine populations of a rural community in the Southern Ecuadorian Andes. From the 1059 inhabitants, 800 serum samples and 958 stool samples could be collected. In addition, 646 from the estimated 1148 pigs were tongue inspected. Circulating antigen was detected by enzyme linked immunosorbent assay (Ag-ELISA) in 2.25% of the human population, whereas intestinal taeniasis was detected in 1.46% by the formalin-ether technique. Following treatment and recovery of tapeworm fragments these were all identified as T. solium. Porcine cysticercosis was diagnosed in 3.56% of the pigs by tongue inspection. In addition, enzyme linked immunoelectrotransfer blot (EITB) was performed on a subset group of 100 humans to confirm the results of the Ag-ELISA. One hundred serum samples from pigs were also analysed by EITB. It appeared that 43 and 74% of humans and pigs had antibodies against T. solium cysticerci, respectively. It is concluded that contrary to the high exposure of the human population to T. solium that is suggested by EITB, the number of active cysticercosis cases, diagnosed by Ag-ELISA, was low, which may indicate endemic stability. The further use of complementary diagnostic methods for a better understanding of the epidemiology of T. solium is suggested.

Assessment of a two-step nucleic acid amplification assay for detection of Neisseria meningitidis followed by capsular genogrouping

Immediate prevention of meningococcal disease relies in part on the prompt treatment with antibiotics of household and other close contacts of cases; however intervention with effective vaccination relies on identification of serogroup-causing strains. Parenteral antibiotic for patient with suspected meningococcal disease before hospital admission is currently recommended. Laboratory standard methods are hindered by failure to detect bacteria by this medical approach to improve patient prognosis. We assessed two polymerase chain reaction (PCR) assays to detect (crgA) and define the serogroups (siaD, orf-2, and ctrA) of Neisseria meningitidis in 120 cerebrospinal fluid (CSF) samples from positive cases (culture or antigen detection or direct smear). The PCR sensitivity for the identification of N. meningitidis was 100% (95% confidence interval, CI, 96-100%) compared to a sensitivity of 46% for culture (95% CI 37-55%), 61% for latex agglutination test (95% CI 52-70%), and 68% for Gram stain (95% CI 59-76%); PCR specificity was 97% (95% CI 82-100%). PCR correctly identified the serogroups A, B, C, W135, Y, and X in CSF samples with a sensitivity of 88% (95% CI 80-93%); the primer sets were 100% specific. The introduction of PCR-based assays shall increase laboratory confirmed cases, consequently enhancing surveillance of meningococcal disease.

Assessment of schistosomiasis, through school surveys, in the Forest Zone of Pernambuco, Brazil

This work had the objective of assessing the present epidemiological situation regarding schistosomiasis through performing Kato-Katz coproscopic tests on representative samples of schoolchildren from each of the 43 municipality of endemic area of the state of Pernambuco, Brazil. The methodology is recommended by the World Health Organization to conduct sampled surveys among children at elementary school levels, ideal target group for baseline surveys: (i) schools are accessible; (ii) the greatest prevalence of schistosomiasis is found within this group; (iii) the data gathered from this age group can be used for intervention within the community as a whole. The following infection indicators were utilized: positivity (percentage of individuals examined with eggs of Schistosoma mansoni in the feces) and severity (geometric mean number of eggs per gram of feces, epg). These indicators allowed the area in general and the municipalities in particular to be categorized into prevalence and severity classes for S. mansoni. The prevalence classes were: low (<10%), medium (> 10 and < 50%), and high (> 50%); the severity classes were: low (1-99 epg), moderate (100-399 epg), and severe (> 400 epg). For the geohelminthic diseases, the following indicators were used: positivity for each geohelminth (percentage of individuals examined with eggs of geohelminths), and cumulative positivity (percentage of individuals examined with eggs of at least one geohelminth). The municipalities were categorized by means of their cumulative positivity into the following geohelminth prevalence classes (WHO 2002): low (< 50%), medium (> 50 and < 70%), and high (> 70%). The study covered 271 schools in 179 different localities, thus giving a total of 11,234 examinations performed. The overall positivity for S. mansoni was 14.4% and the egg count for this parasite in the feces gave a geometric mean of 67.9 epg which suggests a low general state of infection. These results allow this mesoregion to be categorized as presenting medium prevalence and low severity of schistosomiasis. The overall positivity rates for the geohelminths, Ascaris lumbricoides, Ancylostomidae, and Trichuris trichiura were, respectively, 30.4, 10.1, and 27.8%; the cumulative positivity was 45.4%. These results allow this mesoregion to be categorized as presenting low prevalence of geohelminthic diseases. The data show some municipalities in Pernambuco with prevalence greater than 20%, while others presented parasite loads greater than 100 epg. These indicators attest to the significant morbidity due to schistosomiasis regarding to the severity of infections established in young populations.

Assessment of a DNA vaccine encoding an anchored-glycosylphosphatidylinositol tegumental antigen complexed to protamine sulphate on immunoprotection against murine schistosomiasis

Protamine sulphate/DNA complexes have been shown to protect DNA from DNase digestion in a lipid system for gene transfer. A DNA-based vaccine complexed to protamine sulphate was used to induce an immune response against Schistosoma mansoni anchored-glycosylphosphatidylinositol tegumental antigen in BALB/c mice. The protection elicited ranged from 33 to 44%. The spectrum of the elicited immune response induced by the vaccine formulation without protamine was characterized by a high level of IgG (IgG1> IgG2a). Protamine sulphate added to the DNA vaccine formulation retained the green fluorescent protein encoding-plasmid longer in muscle and spleen. The experiments in vivo showed that under protamine sulphate effect, the scope of protection remained unchanged, but a modulation in antibody production (IgG1= IgG2a) was observed.

In vitro antiplasmodial activity and toxicity assessment of plant extracts used in traditional malaria therapy in the Lake Victoria Region

As part of our program screening the flora of the Lake Victoria Region, a total of 54 organic extracts from seven plant families (8 species) were individually tested for antiplasmodial activity against chloroquine-sensitive [Sierra Leone (D-6)] and chloroquine-resistant [Vietnam (W-2)] strains. Only 22% of these extracts exhibited very high in vitro antiplasmodial activity. Six methanol (MeOH) extracts and one chloroform extract showed in vitro antiplasmodial activity against the D-6 Plasmodium falciparum strain, while only three MeOH extracts were active against the W-2 strain. All of the ethyl acetate extracts proved to be inactive against both strains of P. falciparum. A brine shrimp cytotoxicity assay was used to predict the potential toxicity of the extracts. The cytotoxicity to antiplasmodial ratios for the MeOH extracts were found to be greater than 100, which could indicate that the extracts are of low toxicity.

Wild Triatoma infestans, a potential threat that needs to be monitored

The current persistence of Triatoma infestans, and therefore of Chagas disease transmission, in the Andean valleys of Bolivia and the Gran Chaco (precisely where wild populations of the vector are widespread), indicates a possible relationship between these two occurrences. This paper provides an overview of the current knowledge regarding wild T. infestans in Bolivia. The different morphs of the wild vector, their known distributions and some traits of their biology and ecology are presented. Particularly interesting is the considerable behavioural and chromatic plasticity that is displayed by wild T. infestans. According to the biogeographic region, different morphs of the vector occur in rupicolous habitats (common form and Mataral morph in Andean wild T. infestans) or arboreal ones ("dark morph" populations from the Chaco). The high genetic variability found at the microgeographical scale in Andean wild T. infestans favours the hypothesis that the Andes were the centre of origin and dispersal of T. infestans throughout South America. The relevant question regarding the origin of domestic populations is also addressed. Finally, current considerations of the epidemiological significance of wild T. infestans are discussed in the context of recent discoveries. Even if several observations support the epidemiological risk represented by wild T. infestans, the climatic and environmental conditions of their distribution areas would not favour the continued flow of triatomines between sylvatic refuges and domestic environments.

Schistosoma mansoni: magnetic resonance analysis of liver fibrosis according to WHO patterns for ultrasound assessment of schistosomiasis-related morbidity

For the last two decades, ultrasound (US) has been considered a surrogate for the gold standard in the evaluation of liver fibrosis in schistosomiasis. The use of magnetic resonance imaging (MRI) is not yet standardised for diagnosing and grading liver schistosomal fibrosis. The aim of this paper was to analyse MRI using an adaptation of World Health Organization (WHO) patterns for US assessment of schistosomiasis-related morbidity. US and MRI were independently performed in 60 patients (42.1 ± 13.4 years old), including 37 men and 23 women with schistosomiasis. Liver involvement appraised by US and MRI was classified according to the WHO protocol from patterns A-F. Agreement between image methods was evaluated by kappa index (k). The correlation between US and MRI was poor using WHO patterns [k = 0.14; confidence interval (CI) 0.02; 0.26]. Even after grouping image patterns as "A-D", "Dc-E" and "Ec-F", the correlation between US and MRI remained weak (k = 0.39; CI 0.21; 0.58). The magnetic resonance adaptation used in our study did not confirm US classification of WHO patterns for liver fibrosis.

Assessment of the treatment of chronic hepatitis C in the state of Mato Grosso, central Brazil

In Brazil, the treatment of hepatitis C virus (HCV) infection is funded by the national public health system (SUS). To evaluate treatment results in the state of Mato Grosso, central Brazil, we have consulted the files of the office of the State Department of Health responsible for supplying such medications. We obtained information on 232 treatments of 201 patients who underwent treatment in or prior to 2008. The study was conducted by reviewing medical records, making telephone calls and interviewing the assistant physicians. Thirty-nine patients (19.4%) had cirrhosis and HCV genotype 1 predominated (64.3%). Excluding patients with comorbidities or treatment without ribavirin we analysed 175 treatments (sustained virologic response occurred in 32.6% of cases). Twenty-six of these 175 were retreatments and the sustained virological response (SVR) rate among them was 30.8%; the SVR rate was 32.9% among those receiving treatment for the first time. The SVR rate of genotype 1 patients was 27.8%, whereas it was 37.5% in non-1 genotype patients. The adjusted multivariate analysis showed association of SVR with the absence of cirrhosis [odds ratio (OR): 7.7; confidence interval (CI) 95%: 2.5, 33.3], the use of pegylated interferon (OR: 5.8; CI 95%: 1.5, 21.4), non-1 genotype (OR: 5.3; CI 95%: 1.7, 16.7) and uninterrupted treatment (OR: 9.0; CI 95%: 3.3, 45.4). The SVR rates were similar to those found in other Brazilian studies about HCV, but lower than those found in national and international clinical trials. These data suggest that the treatments of chronic hepatitis C that are made available by SUS does not, under normal conditions, work as well as the original controlled studies indicated.

Morphological and morphometrical assessment of spermathecae of Aedes aegypti females

The vectorial capacity of Aedes aegypti is directly influenced by its high reproductive output. Nevertheless, females are restricted to a single mating event, sufficient to acquire enough sperm to fertilize a lifetime supply of eggs. How Ae. aegypti is able to maintain viable spermatozoa remains a mystery. Male spermatozoa are stored within either of two spermathecae that in Ae. aegypti consist of one large and two smaller organs each. In addition, each organ is divided into reservoir, duct and glandular portions. Many aspects of the morphology of the spermatheca in virgin and inseminated Ae. aegypti were investigated here using a combination of light, confocal, electron and scanning microscopes, as well as histochemistry. The abundance of mitochondria and microvilli in spermathecal gland cells is suggestive of a secretory role and results obtained from periodic acid Schiff assays of cell apexes and lumens indicate that gland cells produce and secrete neutral polysaccharides probably related to maintenance of spermatozoa. These new data contribute to our understanding of gamete maintenance in the spermathecae of Ae. aegypti and to an improved general understanding of mosquito reproductive biology.

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.

In vivo assessment of antiretroviral therapy-associated side effects

Antiretroviral therapy has been associated with side effects, either from the drug itself or in conjunction with the effects of human immunodeficiency virus infection. Here, we evaluated the side effects of the protease inhibitor (PI) indinavir in hamsters consuming a normal or high-fat diet. Indinavir treatment increased the hamster death rate and resulted in an increase in triglyceride, cholesterol and glucose serum levels and a reduction in anti-oxLDL auto-antibodies. The treatment led to histopathological alterations of the kidney and the heart. These results suggest that hamsters are an interesting model for the study of the side effects of antiretroviral drugs, such as PIs.

Malaria in the state of Rio de Janeiro, Brazil, an Atlantic Forest area: an assessment using the health surveillance service

The lethality of malaria in the extra-Amazonian region is more than 70 times higher than in Amazonia itself. Recently, several studies have shown that autochthonous malaria is not a rare event in the Brazilian southeastern states in the Atlantic Forest biome. Information about autochthonous malaria in the state of Rio de Janeiro (RJ) is scarce. This study aims to assess malaria cases reported to the Health Surveillance System of the State of Rio de Janeiro between 2000-2010. An average of 90 cases per year had parasitological malaria confirmation by thick smear. The number of malaria notifications due to Plasmodium falciparum increased over time. Imported cases reported during the period studied were spread among 51% of the municipalities (counties) of the state. Only 35 cases (4.3%) were autochthonous, which represents an average of 3.8 new cases per year. Eleven municipalities reported autochthonous cases; within these, six could be characterised as areas of residual or new foci of malaria from the Atlantic Forest system. The other 28 municipalities could become receptive for transmission reintroduction. Cases occurred during all periods of the year, but 62.9% of cases were in the first semester of each year. Assessing vulnerability and receptivity conditions and vector ecology is imperative to establish the real risk of malaria reintroduction in RJ.

Assessment of immunological changes in Epstein-Barr virus co-infection in Egyptian chronic HCV patients

Epstein-Barr virus (EBV) plays a major role in liver pathology. Similar to other members of the herpesvirus family, EBV establishes a persistent infection in more than 90% of adults. The aim of this study was to evaluate the impact of EBV and chronic hepatitis C co-infection (HCV) on biochemical and immunological responses in patients. The study was conducted in 62 patients and 33 apparently healthy controls. Patients were divided into three groups: group I, consisting of 31 patients with chronic hepatitis C infection (CHC), group II, consisting of eight patients with EBV infection and without HCV infection and group III, consisting of 23 patients with EBV and chronic HCV. The percentage of CD3+ cells, helper CD4+ cells and CD19+ B-cells was measured by flow cytometry. Human interferon-γ (IFN-γ) and interleukin (IL)-15 levels were measured by an ELISA. The levels of liver alanine aminotransferase and aspartate aminotransferase enzymes were higher in EBV/HCV patients compared to that in EBV and HCV mono-infected patients. EBV/HCV patients had significantly reduced percentages of CD3+ and CD4+ cells compared to EBV patients. Serum IFN-γ levels were significantly reduced in EBV/HCV patients (3.86 pg/mL) compared to CHC patients (6.76 pg/mL) and normal controls (4.69 pg/mL). A significant increase in serum IL-15 levels was observed in EBV/HCV patients (67.7 pg/mL) compared to EBV patients (29.3 pg/mL). Taken together, these observations suggest that HCV and EBV co-infection can potentiate immune response dampening in patients.