Impact of dams and irrigation schemes in Anopheline (Diptera: Culicidae) bionomics and malaria epidemiology

Irrigation schemes and dams have posed a great concern on public health systems of several countries, mainly in the tropics. The focus of the present review is to elucidate the different ways how these human interventions may have an effect on population dynamics of anopheline mosquitoes and hence, how local malaria transmission patterns may be changed. We discuss different studies within the three main tropical and sub-tropical regions (namely Africa, Asia and the Pacific and the Americas). Factors such as pre-human impact malaria epidemiological patterns, control measures, demographic movements, human behaviour and local Anopheles bionomics would determine if the implementation of an irrigation scheme or a dam will have negative effects on human health. Some examples of successful implementation of control measures in such settings are presented. The use of Geographic Information System as a powerful tool to assist on the study and control of malaria in these scenarios is also highlighted.

Prevalence and risk factors for intestinal protozoa infection in elderly residents at Long Term Residency Institutions in Southeastern Brazil

This study determined the prevalence of intestinal protozoa in Long Term Residency Institutions for the Elderly (ILPI) in elders, nurses and food handlers, identifying the risk factors associated with the infections. Stool samples taken from the elderly (n = 293), nurses (63) and food handlers (19) were studied. Questionnaires were used with questions related to sociodemographic variables, health, behavior and health characteristics. Stool samples were examined using the techniques of Faust and Ziehl Neelsen, and the prevalence of G. duodenalis, Cryptosporidium spp., E. histolytica/dispar in the elderly was 4.0%, 1.0% and 0.3% respectively. Nurses and food handlers showed 4.8% and 5.2% positivity only for G. duodenalis, respectively. The origin of the individuals and contact with domestic animals has been associated with infection by G. duodenalis in the elderly, and contact with domestic animals was considered a risk factor for infection. The last stool examinations were related to Cryptosporidium spp.. None of the variables were associated with E. histolytica/dispar. The frequency of hand washing was significantly associated with G. duodenalis among nurses. The frequency of positive samples of G. duodenalis, Cryptosporidium spp., E. histolytica/dispar showed that ILPIs environments are conducive to this occurring due to contact between the elderly, nurses and food handlers, which are often poorly trained in hygiene procedures and food handling.

USE OF THE POLYMERASE CHAIN REACTION FOR THE DIAGNOSIS OF ASYMPTOMATIC Leishmania INFECTION IN A VISCERAL LEISHMANIASIS-ENDEMIC AREA

The diagnosis of asymptomatic infection with Leishmania (Leishmania) chagasi has become more important over recent years. Expansion of visceral leishmaniasis might be associated with other routes of transmission such as transfusion, congenital or even vector transmission, and subjects with asymptomatic infection are potential reservoirs. Moreover, the identification of infection may contribute to the management of patients with immunosuppressive conditions (HIV, transplants, use of immunomodulators) and to the assessment of the effectiveness of control measures. In this study, 149 subjects living in a visceral leishmaniasis endemic area were evaluated clinically and submitted to genus-specific polymerase chain reaction (PCR), serological testing, and the Montenegro skin test. Forty-nine (32.9%) of the subjects had a positive PCR result and none of them developed the disease within a follow-up period of three years. No association was observed between the results of PCR, serological and skin tests. A positive PCR result in subjects from the endemic area did not indicate a risk of progression to visceral leishmaniasis and was not associated with a positive result in the serological tests.

EXPERIMENTAL INFECTION OF SWISS AND AKR/J MICE WITH Centrocestus formosanus (TREMATODA: HETEROPHYIDAE)

In order to better understand the biology of Centrocestus formosanus in a definitive host model, mice of Swiss and AKR/J strains were experimentally infected with 100 metacercariae of the parasite. Fourteen days post-infection, the rodents were killed and adult trematodes were recovered from the small intestine. The percentage of parasite recovery from AKR/J mice (11.4%) was significantly higher than that from Swiss mice (5.3%). Moreover, trematodes recovered from the AKR/J strain were more developed and had greater fecundity. Peculiarities concerning the mice’s immune system could explain the difference in susceptibility and in worm development seen in the present study. The data obtained confirm that mice are susceptible to infection with C. formosanus and indicate that the AKR/J strain provides a more favorable environment for parasite development.

PARASITOLOGICAL AND MOLECULAR DIAGNOSIS IN EXPERIMENTAL Strongyloides venezuelensis INFECTION

Strongyloides venezuelensis is a parasitic nematode of rats which is frequently used as a model to study human and animal strongyloidiasis. The aim of this study was to evaluate the correlation between parasitological and molecular diagnosis in Strongyloides venezuelensis infection. PCR assays were used to detect S. venezuelensis DNA in fecal samples obtained from experimentally infected Rattus norvegicus. The results showed a higher sensitivity of the PCR assay in detecting the infection compared to parasitological methods.

Evaluation of three different DNA extraction methods from blood samples collected in dried filter paper in Plasmodium subpatent infections from the Amazon region in Brazil

Asymptomatic Plasmodium infection is a new challenge for public health in the American region. The polymerase chain reaction (PCR) is the best method for diagnosing subpatent parasitemias. In endemic areas, blood collection is hampered by geographical distances and deficient transport and storage conditions of the samples. Because DNA extraction from blood collected on filter paper is an efficient method for molecular studies in high parasitemic individuals, we investigated whether the technique could be an alternative for Plasmodium diagnosis among asymptomatic and pauciparasitemic subjects. In this report we compared three different methods (Chelex®-saponin, methanol and TRIS-EDTA) of DNA extraction from blood collected on filter paper from asymptomatic Plasmodium-infected individuals. Polymerase chain reaction assays for detection of Plasmodium species showed the best results when the Chelex®-saponin method was used. Even though the sensitivity of detection was approximately 66% and 31% for P. falciparum and P. vivax, respectively, this method did not show the effectiveness in DNA extraction required for molecular diagnosis of Plasmodium. The development of better methods for extracting DNA from blood collected on filter paper is important for the diagnosis of subpatent malarial infections in remote areas and would contribute to establishing the epidemiology of this form of infection.

Sepsis Mortality Prediction Based on Predisposition, Infection and Response

OBJECTIVE: To empirically test, based on a large multicenter, multinational database, whether a modified PIRO (predisposition, insult, response, and organ dysfunction) concept could be applied to predict mortality in patients with infection and sepsis. DESIGN: Substudy of a multicenter multinational cohort study (SAPS 3). PATIENTS: A total of 2,628 patients with signs of infection or sepsis who stayed in the ICU for >48 h. Three boxes of variables were defined, according to the PIRO concept. Box 1 (Predisposition) contained information about the patient's condition before ICU admission. Box 2 (Injury) contained information about the infection at ICU admission. Box 3 (Response) was defined as the response to the infection, expressed as a Sequential Organ Failure Assessment score after 48 h. INTERVENTIONS: None. MAIN MEASUREMENTS AND RESULTS: Most of the infections were community acquired (59.6%); 32.5% were hospital acquired. The median age of the patients was 65 (50-75) years, and 41.1% were female. About 22% (n=576) of the patients presented with infection only, 36.3% (n=953) with signs of sepsis, 23.6% (n=619) with severe sepsis, and 18.3% (n=480) with septic shock. Hospital mortality was 40.6% overall, greater in those with septic shock (52.5%) than in those with infection (34.7%). Several factors related to predisposition, infection and response were associated with hospital mortality. CONCLUSION: The proposed three-level system, by using objectively defined criteria for risk of mortality in sepsis, could be used by physicians to stratify patients at ICU admission or shortly thereafter, contributing to a better selection of management according to the risk of death.

SEROPREVALENCE OF CHAGASIC INFECTION IN YOUNG INDIVIDUALS IN A BLOOD CENTER IN THE STATE OF SAO PAULO, BRAZIL

SUMMARY This study aimed at estimating the number of cases of non-negative serological reactions to Chagas disease in blood donors at the Blood Center of Botucatu, São Paulo, Brazil, from 2003 to 2010 and at relating them to their cities of origin. Five hundred and seventy-four non-negative results for Chagas disease were evaluated. Of these, 371 (64.8%) were reagent, and 203 (35.4%) were inconclusive. The prevalence of Chagas disease in blood donors was 0.05%. There were, on average, 72 cases/year, and a prevalence of males was observed (64.8%). Forty-three (7.49%) individuals were 18 to 30 years old; 92 (16.02%) were 31 to 40; 147 (25.61%) 41 to 50, and 292 (50.87%) were older than 50 years. It was observed that 29.3% of females with reagent serology were at their fertile age (18 and 45 years). The majority of donors were originally from cities in the southwestern and central regions of São Paulo, but individuals from other states contributed with 20%. The provenance of most donors was the city of Botucatu/SP, followed by the city of Taquarituba/SP. Therefore, the profile of donors at this blood center favors the occurrence of a larger number of non-negative serological reactions. Although there has been a significant reduction in the number of new cases/year for this disease, it is still a public-health problem, and results suggest the need for new epidemiological assessments in the studied region.

CO-INFECTION OF DENGUE VIRUS BY SEROTYPES 1 AND 4 IN PATIENT FROM MEDIUM SIZED CITY FROM BRAZIL

SUMMARY The natural co-infection with dengue virus can occur in highly endemic areas where different serotypes have been observed for many years. We report one case of DENV-1/DENV-4 co-infection in human serum detected by molecular tests. Phylogenetic analysis of the sequences obtained indicated the presence of genotype V and II for DENV-1 and DENV-4, respectively.

NATURAL INFECTION BY Trypanosoma cruzi IN ONE DOG IN CENTRAL WESTERN BRAZIL: A CASE REPORT

SUMMARY It is estimated that about 10 million people are infected with Trypanosoma cruzi worldwide, mostly in Latin America and more than 25 million are at risk of acquiring this infection in endemic areas. Dogs are an important reservoir for this pathogen and thus, considered a risk factor for human populations. This report describes one case of Chagas disease in a dog from Cuiabá, Mato Grosso State, Brazil. The diagnosis was obtained by direct examination of trypomastigote forms in blood smears. Amastigotes forms were visualized in microscopy of the bone marrow, lymph nodes, kidneys, liver and brain. The T. cruzi (ZIII) infection was confirmed by Polymerase Chain Reaction, and sequencing. The animal presented multisystemic failure and died. Although acute Chagas disease in humans is not reported in Cuiabá, this is the first report of a canine case in this region. This case represents a warning, to health professionals and authorities, to the possibility of transmission of this zoonosis in Cuiabá.

HIGH PREVALENCE OF Strongyloides stercoralis INFECTION AMONG THE ELDERLY IN BRAZIL

SUMMARY Little is known about the frequency of intestinal parasites in the elderly due to a lack of attention given to the occurrence of these infections among older adults. This study compares the frequency of Strongyloides stercoralis and other enteroparasites between elderly living in nursing homes (n = 100) and those noninstitutionalized (n = 100) from Uberlândia, state of Minas Gerais, southeastern Brazil, associated with data of epidemiological and socio-demographic conditions. Through coproparasitological examination of both groups, enteroparasites were detected in 15 of 200 individuals examined (7.5%; CI: 5.1- 9.9). S. stercoralis was the most frequent parasite 10/200 (5%; CI: 4.2-5.8), being significantly higher in males and in individuals with autonomy for daily living activities. There were no statistical differences in the prevalence of parasites between the two groups compared. In conclusion, S. stercoralis infection was highly prevalent in elderly patients and it does not depend on whether the individual was institutionalized or not.

PREVALENCE OF HERPES SIMPLEX VIRUS TYPE 2 AND RISK FACTORS ASSOCIATED WITH THIS INFECTION IN WOMEN IN SOUTHERN BRAZIL

SUMMARY The herpes simplex virus type 2 (HVS-2) is the most prevalent infection worldwide. It is a cofactor in the acquisition of human immunodeficiency virus (HIV) and the persistence of human papillomavirus (HPV). This study evaluated the prevalence of HSV-2, using the polymerase chain reaction (PCR), and associated factors in patients treated at the Federal University of Rio Grande (FURG) and Basic Health Units (BHU) in Rio Grande, Brazil. The observed prevalence of HSV-2 was 15.6%. Among the 302 women studied, 158 had received assistance in BHU and 144 were treated at FURG. The prevalence of HSV-2 in these groups was 10.8% and 20.8%, respectively, RR 1.9 and p = 0.012. Knowledge about the Pap smear, and the presence of lesions showed no association with HSV-2 infection. Multivariate analysis showed that the variable that most influenced the risk of HSV-2 infection was the presence of HIV infection, with a relative risk of 1.9 and p = 0.04. Discussion: Genital ulcers are an important entry point for HIV, and condom use is an important strategy to reduce transmission of HIV and HSV-2.

AN UPWARD TREND IN DNA P16INK4A METHYLATION PATTERN AND HIGH RISK HPV INFECTION ACCORDING TO THE SEVERITY OF THE CERVICAL LESION

SUMMARY High-risk human papillomavirus (hr-HPV) infection is necessary but not sufficient for cervical cancer development. Recently, P16INK4A gene silencing through hypermethylation has been proposed as an important cofactor in cervical carcinogenesis due to its tumor suppressor function. We aimed to investigate P16INK4A methylation status in normal and neoplastic epithelia and evaluate an association with HPV infection and genotype. This cross-sectional study was performed with 141 cervical samples from patients attending Hospital Moncorvo Filho, Rio de Janeiro. HPV detection and genotyping were performed through PCR and P16INK4A methylation by nested-methylation specific PCR (MSP). HPV frequency was 62.4% (88/141). The most common HPV were HPV16 (37%), HPV18 (16.3%) and HPV33/45(15.2%). An upward trend was observed concerning P16INK4A methylation and lesion degree: normal epithelia (10.7%), low grade lesions (22.9%), high grade (57.1%) and carcinoma (93.1%) (p < 0.0001). A multivariate analysis was performed to evaluate an association between methylation, age, tobacco exposure, HPV infection and genotyping. A correlation was found concerning methylation with HPV infection (p < 0.0001), hr-HPV (p = 0.01), HSIL (p < 0.0007) and malignant lesions (p < 0.0001). Since viral infection and epigenetic alterations are related to cervical carcinoma, we suggest that P16INK4A methylation profile maybe thoroughly investigated as a biomarker to identify patients at risk of cancer.

PROTECTIVE EFFECT OF THE PROBIOTIC Saccharomyces boulardii IN Toxocara canis INFECTION IS NOT DUE TO DIRECT ACTION ON THE LARVAE

SUMMARY In a previous study our group found that the probiotic Saccharomyces boulardii was capable of reducing the intensity of infection in mice with toxocariasis. In order to assess whether the mechanism involved would be a direct action of the probiotic on Toxocara canis larvae, this study was designed. Both probiotics were singly cultivated in plates containing RPMI 1640 medium and T. canis larvae. S. boulardii and B. cereus var. toyoi cultures presented 97.6% and 95.7% of larvae with positive motility, respectively, and absence of color by the dye trypan blue, not representing significant difference to the control group (p > 0.05). We conclude that none of the probiotics showed in vitro effects on T. canis larvae and that the interaction with the intestinal mucosa is necessary for the development of the protective effect of S. boulardii.