Comparative study of the in-hospital case-fatality rate of leptospirosis between pediatric and adult patients of different age groups

The main objective was to compare the in-hospital case-fatality rate of leptospirosis between pediatric (< 19 years) and adult (>19 years) patients, taking into account gender, renal function, duration of symptoms and jaundice. Medical records of 1016 patients were reviewed. Comparative analysis was restricted to 840 patients (100 pediatric, 740 adults) with recorded information on the variables included in the analysis. Among these patients 81.7% were male and 91.5% were icteric. The case-fatality rate of leptospirosis was 14.4%. The odds of death adjusted for gender, jaundice, duration of symptoms, serum urea and serum creatinine were almost four times higher for the adult than for the pediatric group (odds ratio (OR) = 3.94; 95% confidence interval = 1.19-13.03, p = 0.029). Among adults, increased age was also significantly and independently associated with increased risk of death (p < 0.01). Older patients were also more often treated by dialysis. In conclusion, the data suggest that the in-hospital case fatality rate of leptospirosis is higher for adults than for children and adolescents, even after taking into account the effects of several potential risk factors of death. Among adults, older age was also strongly and independently associated with higher risk of death.

The frequency rate of Toxocara species contamination in soil samples from public yards in a urban area "Payathai", Bangkok, Thailand

Toxocara species are most common roundworms of Canidae and Felidae. Human toxocariasis develops by ingesting of embryonated eggs in contaminated soil. There is no previous report of Toxocara contamination in the soil samples from the public areas in Bangkok. For this reason our study have been carried out to examine the frequency of Toxocara eggs in public yards in Bangkok, Thailand. A total of 175 sand and clay samples were collected and examined for parasite eggs. According to this study, Toxocara eggs were detected from 10 (5.71%) of 175 soil samples. The high rate of contamination in this study implies the importance of the control of this possible zoonotic disease: control of abandon of dogs and cats, is still necessary.

Evolution of genotypes of Group A streptococci from colonization and infection

Dissertação para obtenção do Grau de Doutor em Biologia

A module for the FTT-SE protocol in ns-3

Demo in Workshop on ns-3 (WNS3 2015). 13 to 14, May, 2015. Castelldefels, Spain.

Enzootic transmission of Trypanosoma cruzi and T. rangeli in the Federal District of Brazil

The Federal District of Brazil (DF) lies within the Cerrado biome, where open shrubland (savannas) is interspersed with riverside gallery forests and permanent swamps (veredas). Trypanosoma cruzi-infected native triatomines occur in the area, but the enzootic transmission of trypanosomatids remains poorly characterized. A parasitological survey involving sylvatic triatomines (166 Rhodnius neglectus collected from Mauritia flexuosa palms) and small mammals (98 marsupials and 70 rodents, totaling 18 species) was conducted in 18 sites (mainly gallery forests and veredas) of the DF. Parasites were isolated, morphologically identified, and characterized by PCR of nuclear (mini-exon gene) and kinetoplast DNA (kDNA). Six R. neglectus, seven Didelphis albiventris and one Akodon cursor were infected by trypanosomes; wild reservoir infection is documented for the first time in the DF. kDNA PCR detected T. cruzi in five R. neglectus and mini-exon gene PCR revealed T. cruzi I in isolates from D. albiventris. Parasites infecting one bug yielded T. rangeli KP1+ kDNA amplicons. In spite of the occurrence of T. cruzi-infected D. albiventris (an important wild and peridomestic reservoir) and R. neglectus (a secondary vector displaying synanthropic behavior), a low-risk of human Chagas disease transmission could be expected in the DF, considering the low prevalence infection recorded in this work. The detection of T. rangeli KP1+ associated with R. neglectus in the DF widens the known range of this parasite in Brazil and reinforces the hypothesis of adaptation of T. rangeli populations (KP1+ and KP1-) to distinct evolutionary Rhodnius lineages.

A Triatoma maculata (Hemiptera, Reduviidae, Triatominae) population from Roraima, Amazon region, Brazil, has some bionomic characteristics of a potential Chagas disease vector

Even though Chagas disease is rare in the Brazilian Amazon, the conditions for the establishment of domiciliated cycles prevail in many areas where triatomines are of frequent occurrence. In Roraima, a previous serological and entomological survey in three agricultural settlements showed the existence of all transmission cycle elements, i.e., individuals infected by Trypanosoma cruzi, triatomine species previously found harboring T. cruzi in the broader Amazon region of neighboring countries and, domicile/ peridomicile conditions favorable to triatomine colonization. Triatoma maculata was the most frequent species, found in chicken houses in the peridomicile and sporadically within residences. Aiming to investigate the possibility of T. maculata to possess the potentiality to transmit T. cruzi in the area, bionomic characteristics were studied under laboratory conditions. These were feeding frequency, time for defecation after a blood meal, time elapsed in voluntary fasting pre- and pos-ecdysis, moulting time periods, pre-oviposition and oviposition periods and index of oviposition, incubation period, egg viability, longevity and mortality rate. Results show that the Passarão population of T. maculata should be considered a potential vector of T. cruzi since it shows a capacity to infest artificial ecotopes in the peridomicile, to carry out large number of meals during the nymphal cycle, to have a relatively short developmental cycle capable of producing 2.9 generations/year, to blood source eclecticism, to defecate immediately after the blood meal while still on the host and to the fact that has been previously found naturally infected by T.cruzi.

Molecular screening of Plasmodium sp. asymptomatic carriers among transfusion centers from Brazilian Amazon region

The transmission of malaria in Brazil is heterogeneous throughout endemic areas and the presence of asymptomatic Plasmodium sp. carriers (APCs) in the Brazilian Amazon has already been demonstrated. Malaria screening in blood banks is based on the selection of donors in respect to possible risks associated with travel or residence, clinical evidence and/or inaccurate diagnostic methods thereby increasing the probability of transfusion-transmitted infection. We evaluated the frequency of APCs in four blood services in distinct areas of the Brazilian Amazon region. DNA was obtained from 400 human blood samples for testing using the phenol-chloroform method followed by a nested-PCR protocol with species-specific primers. The positivity rate varied from 1 to 3% of blood donors from the four areas with an average of 2.3%. All positive individuals had mixed infections for Plasmodium vivax and Plasmodium falciparum. No significant differences in the results were detected among these areas; the majority of cases originated from the transfusion centres of Porto Velho, Rondônia State and Macapá, Amapá State. Although it is still unclear whether APC individuals may act as reservoirs of the parasite, efficient screening of APCs and malaria patients in Brazilian blood services from endemic areas needs to be improved.

Sexual transmission of hepatitis C

It is generally agreed that the hepatitis C virus (HCV) can be efficiently transmitted parenterally, although data on viral transmission by sexual or non-sexual intrafamilial contact are conflicting. Since data collection began in 1989, the first study dealt with the risk of sexual transmission among multiple sex partners. Other investigations followed, emphasizing that risk increases in specific groups such as patients co-infected with HIV and HBV, sex workers, homosexuals, illicit drug users and patients attended at sexually transmittable disease clinics. The question arises as to what might be the risk for monogamous heterosexuals in the general population, in which one of the partners has HCV? The literature provides overall rates that vary from zero to 27%; however, most studies affirm that the chances of sexual transmission are low or almost null, with rates for this mode fluctuating from zero to 3%. Intrafamilial transmission is strongly considered but inconclusive, since when mentioning transmission between sex partners within the same household, specific situations also should be considered, such as the sharing of personal hygiene items, like razorblades, toothbrushes, nail clippers and manicure pliers, which are important risk factors in HCV transmission. In this review, we discuss the hypotheses of sexual and/or intrafamilial transmission.

A study in cross-cultural transmission of natural philosophy: the Kenkon Bensetsu

Dissertação apresentada para cumprimento dos requisitos necessários à obtenção do grau de Doutor em História dos Descobrimentos e da Expansão Portuguesa

Biological implications of the phenotypic plasticity in the Schistosoma mansoni - Nectomys squamipes model

The water-rat Nectomys squamipes is mostly important non-human host in schistosomiasis mansoni transmission in Brazil, due to its susceptibility, high abundance and water-contact pattern. During experimental infection of N. squamipes with Schistosoma mansoni, adult worms show phenotypic plasticity. This finding led us to investigate whether biological behavior is also affected. This was assessed comparing the biological characteristics of four S. mansoni strains: BE (State of Belém do Pará), CE (State of Pernambuco), CMO (State of Rio Grande do Norte) and SJ (State of São Paulo) using laboratory-bred N. squamipes. The infection was monitored by determination of the pre-patent period, fecal egg output, egg viability, intestinal egg count and, infectivity rate. No biological modification was observed in these parameters. Overall results highlight that N. squamipes was susceptible to several S. mansoni strains, suggesting that it might contribute to the maintenance of schistosomiasis mansoni in Brazil.

Comparison of small mammal prevalence of Leishmania (Leishmania) mexicana in five foci of cutaneous leishmaniasis in the State of Campeche, Mexico

In the Yucatan Peninsula of Mexico, 95% of the human cases of Cutaneous Leishmaniasis are caused by Leishmania (Leishmania) mexicana with an incidence rate of 5.08 per 100,000 inhabitants. Transmission is limited to the winter months (November to March). One study on wild rodents has incriminated Ototylomys phyllotis and Peromyscus yucatanicus as primary reservoirs of L. (L.) mexicana in the focus of La Libertad, Campeche. In the present study, the prevalence of both infection and disease caused by L. (L.) mexicana in small terrestrial mammals were documented during five transmission seasons (1994-2004) in five foci of Leishmaniasis in the state of Campeche. Foci separated by only 100 km, with similar relative abundances of small mammals, were found to differ significantly in their prevalence of both symptoms and infection. Transmission rates and reservoir species seemed to change in space as well as in time which limited the implementation of effective control measures of the disease even in a small endemic area such as the south of the Yucatan Peninsula.

High prevalence and association of HIV-1 non-B subtype with specific sexual transmission risk among antiretroviral naïve patients in Porto Alegre, RS, Brazil

In South Brazil the circulation of two HIV-1 subtypes with different characteristics represents an important scenario for the study of the impact of HIV-1 diversity on the evolution of the HIV-1 epidemic and AIDS disease. HIV-1 B, the predominant variant in industrialized countries and HIV-1 C, the most prevalent subtype in areas with rapid epidemic growth, are implicated in most infections. We evaluated blood samples from 128 antiretroviral (ARV) naïve patients recruited at entry to the largest HIV outpatient service in Porto Alegre. Based on partial pol region sequencing, HIV-1 C was observed in 29%, HIV-1 B in 22.6% and, the recently identified CRF31_BC, in 23.4% of 128 volunteers. Other variants were HIV-1 F in 10% and other mosaics in 5.5%. In order to evaluate the association of socio-behavioral characteristics and HIV-1 subtypes, interviews and laboratory evaluation were performed at entry. Our data suggest an established epidemic of the three major variants, without any evidence of partitioning in either of the subgroups analyzed. However, anal sex practices were associated with subtype B, which could indicate a greater transmissibility of non-B variants by vaginal intercourse. This study provides baseline information for epidemiologic surveillance of the changes of the molecular characteristics of HIV-1 epidemics in this region.

Preliminary investigation of Culicidae species in South Pantanal, Brazil and their potential importance in arbovirus transmission

In view of the high circulation of migratory birds and the environmental and climatic conditions which favor the proliferation of arthropods, the Brazilian Pantanal is susceptible to circulation of arboviruses. However, the amount of data concerning arbovirus vectors in this area is scarce; therefore the aim of this study was to conduct a preliminary investigation of Culicidae species in the Nhecolândia Sub-region of South Pantanal, Brazil and their potential importance in the arbovirus transmission. A total of 3684 specimens of mosquitoes were captured, 1689 of which caught in the rainy season of 2007, were divided into 78 pools and submitted to viral isolation, Semi-Nested RT-PCR and Nested RT-PCR, with a view to identifying the most important arboviruses in Brazil. Simultaneously, 70 specimens of ticks found blood-feeding on horses were also submitted to the same virological assays. No virus was isolated and viral nucleic-acid detection by RT-PCR was also negative. Nevertheless, a total of 22 Culicidae species were identified, ten of which had previously been reported as vectors of important arboviruses. The diversity of species found blood-feeding on human and horse hosts together with the arboviruses circulation previously reported suggest that the Nhecolândia Sub-region of South Pantanal is an important area for arbovirus surveillance in Brazil.

Transmissão do vírus citomegálico através do aleitamento materno em prematuros

RESUMO: Nas últimas quatro décadas, desenvolveram-se vários estudos, dispersos por todo o mundo, visando analisar a importância da transmissão perinatal do CMV pelo leite materno, nos recém-nascidos prematuros e de baixo peso à nascença. Comparando estes estudos, as taxas de incidência de infecção e doença são extremamente variáveis, não havendo consenso entre os autores. Surgiu, assim, a necessidade de realizar a presente dissertação, pioneira ao nível nacional, com o objectivo de determinar a incidência da infecção perinatal citomegálica, transmitida através do aleitamento materno a recémnascidos prematuros, e identificar as suas consequências clínicas. Para a elaboração deste trabalho foram seleccionados todos os recém-nascidos com idade gestacional inferior a 35 semanas e respectivas mães seropositivas para CMV, internados na Unidade de Cuidados Intensivos de Neonatalogia do Hospital de São Francisco Xavier, entre o período de 1 de Outubro de 2010 e 31 Julho de 2011. Foram analisadas as urinas dos recém-nascidos e o leite materno das mães na primeira, sexta e décima segunda semana pós-parto, utilizando a técnica de Nested-PCR e, posteriormente, a PCR em Tempo Real, para determinar a carga viral do leite materno. Constatou-se que a aquisição da infecção perinatal de CMV no recém-nascido prematuro ocorre com alguma frequência (40,5%), sendo muito provável que a via de transmissão em 38,1% destes casos seja o leite materno infectado, não devendo esta ser desvalorizada. Relativamente às consequências clínicas, não foram observadas alterações clínico-laboratoriais associadas à infecção citomegálica. Analisando os factores que condicionam a transmissão da infecção citomegálica perinatal, estabeleceu-se uma correlação entre a carga viral do leite materno e a transmissão do vírus, permitindo deduzir que quanto maior a carga viral, maior o risco de transmissão. Finalmente, os resultados obtidos sugerem que o risco de transmissão da infecção e suas consequências clínicas não justificam a contra-indicação da amamentação, pois esta comporta, também, elevados benefícios. ----------------ABSTRACT: In the last four decades, several studies were developed all over the world to analyze the importance of CMV perinatal transmission through mother´s milk in the preterm and low birthweight newborns. Comparing these studies, the infection and disease incidence rates are extremely variable, without agreement between the authors. The aim of this study, the first of the kind made in Portugal, is to define the rate of perinatal cytomegalovirus infection in preterm newborns via breastfeeding and its clinical consequences. All the newborns with gestational age below 35 weeks and their CMV seropositive mothers, admitted between the October 1, 2010 and July 31, 2011 in the Neonatology Intensive Care Unit of the São Francisco Xavier Hospital, were included in this study. Human breast milk and urine specimens were collected from mothers and their preterms infants around the 1st, 6th and 12th week after delivery and analyzed by Nested-PCR. The PCR in Real Time was used to determine the breast milk viral load. It was found that the CMV perinatal infection in preterm infants occurs in 40,5% of the cases and most likely 38,1% of these were infected via breastmilk and therefore this should not be overlooked. Considering the clinical consequences, no clinical and laboratory changes associated with cytomegalovirus infection were observed. Analyzing the factors that determine the perinatal transmission of the cytomegalovirus, it was established a correlation between breast milk viral load and viral transmission, allowing to conclude that the higher the viral load the greater the risk of transmission. Finally, the obtained results suggest that the risk of CMV infection and its clinical consequences don´t justify the breastfeeding contraindication because it also provides high benefits.