Efeitos da temperatura no ciclo de vida, exigências térmicas e estimativas do número de gerações anuais de Aedes aegypti (Diptera, Culicidae)

O trabalho teve por objetivo avaliar o efeito da temperatura sobre o ciclo de vida de Aedes aegypti (Linnaeus, 1762), determinar as exigências térmicas para o desenvolvimento e estimar o número de gerações anuais do inseto em campo. O ciclo de vida das populações de A. aegypti foi estudado nas temperaturas de 18, 22, 26, 28, 32 e 34 ± 2ºC e fotofase de 12 horas, determinando-se ainda os limites térmicos inferiores de desenvolvimento (Tb) e as constantes térmicas (K) e estimado o número de gerações anuais do inseto em laboratório e em campo. A temperatura favorável ao desenvolvimento de A. aegypti encontra-se entre 22ºC e 32ºC, e para a longevidade e fecundidade dos adultos entre 22ºC e 28ºC. As Tb, K de ovo a adulto, e o número de gerações anuais em campo foram de 11,33; 8,99 e 13,61ºC, 192,3; 213,2 e 116,5 graus-dias, e 23; 24,6 e 30,3 gerações para as populações de A. aegypti de Boqueirão (07º29'27''S, 36º08'09''W), Campina Grande (07º13'32''S, 35º54'15''W) e Remígio (06º58'1''S, 35º47'29''W), respectivamente.

Indirect immunofluorescence(IgG and IgM) tests for toxoplasmosis on 203 persons, with no symptomatology suggesting the disease, located in the city of Rio de Janeiro. Serological follow up one to two years later.

Clinical and serological follow up examinations were performed on 203 persons, from three to twenty years of age, from the otolaryngology department of a hospital in the city of Rio de Janeiro, with no symptomatology suggesting toxoplasmosis, but suffering from chronic tonsillitis. According to results obtained during the first indirect immunofluorescence tests, the patients were divided into following groups: Group I (non-reactive IgG and IgM), 98 persons (48.3%); Group II (1:16 ≤ IgG ≤ 1:256 and non-reactive IgM), 74 persons (36.5%); Group III (IgM ≥ 1:1024 and non-reactive IgM), 18 persons (8.8%), and Group IV (IgG and IgM reactive), 13 persons (6.4%). One to two years later, 131 (64.5%) of the 203 persons were reexamined by a second indirect immunofluorescence test. In the case of 66 persons (Group I) whose serum was non-reactive in the IgG and IgM classes during the first indirect immunofluorescence test, serum conversion was observed in aproximately 21.2%. in 65 individuals (49.6%), (Groups II, III and IV),with reactive serum in the IgG classes during the first indirect immunofluorescence test, the second reaction showed an increase in titres in 20% of the cases, a decrease in 67.7% of the cases, or no alterations in 12.3 of the cases. In the IgM class, all 131 sera were non-reactive at 116 dilution the second immunofluorescence test, including the 13 cases that had previously been reactive in the immunoglobulin class, Symptomatology suggesting toxoplasmosis was only observed in one case during the second testing, this patient's principal physical sign being hypertrophied lymph nodes. during this period, the Toxoplasma antibodies showed titres of IgG 1:32000 and non-reactive IgM, whilst one year previously, during the first test, these titres were IgG 1:1024 and IgM 1:64. Differences in the age, sex and skin coloring of patients were not statistically significant as regards alterations in the indirect immunofluorescence test titres.

Morte súbita e doença de Chagas - análise dos fatores predisponentes do óbito súbito do chagásico crônico

Com a finalidade de contribuir para o esclarecimento dos mecanismos da morte súbita na forma crônica da tripanossomose cruzi, foram analisados, de modo sistemático, os seguintes aspectos em 116 chagásicos falecidos subitamente: o sexo, a idade em que ocorreu o óbito, a profissão, o papel da emoção e do esforço físico no momento do desenlance fatal e a época da morte em relação às estações do ano. Todos estes tripanossomóticos, aparentemente, não manifestaram, em vida, sintomas e/ou sinais de insuficiência cardíaca. Para análise comparativa utilizou-se um grupo constituído por chagásicos crônicos falecidos com ou após manifestações de insuficiência cardíaca. Os resultados demonstram que o óbito acomete (tanto nos chagásicos falecidos subitamente como naqueles com insuficiência cardíaca) mais freqüentemente o homem que a mulher e que nos chagásicos do sexo masculino falecidos subitamente a morte ocorre mais cedo do que em tripanossomóticos cujo desenlace está asociado ou é precedido por quadro de insuficiência cardíaca. Finalmente, nossos dados sugerem que o esforço físico, os fatores emotivos e as variações sazonais não exercem papel essencial no desencadeamento do óbito do chagásico crônico.

Evaluation of antibody responses in american visceral leishmaniasis by ELISA and immunoblot

American visceral leishmaniasis (AVL) is an important disease among children of northeast Brazil. In order to characterize antibody responses during AVL, sera of hospitalized patients were analyzed by ELISA and Western blot using a Leishmania chagasi antigen preparation. The ELISA was positive (asorbance [greater than or equals to] 0.196) at a serum dilution of 1:1024 in all patients at presentation, and fell to ward control levels over the following year. Only one of 72 control subjects tested positive, and that donor had a sibling with AVL. Immunoblots of the patients' sera recognized multiple bands, the most frequent of which were at approximately 116 kDa, 70 kDa, and 26 kDa. Less frenquently observed were bands at approximately 93 kDa, 74 kDa, 62 kDa, 46 kDa and 32 kDa. The ELISA responses and patterns of banding were distinctive for AVL, and could be used to differentiate patients with AVL from those with Chagas' disease of cutaneous leishmaniasis. Sera from six AVL patients followed for up to six weeks after treatment identified no new bands. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of surface iodinated parasite proteins showed one major band and four minor bands, whereas SDS-PAGE of biotinylated prarasite proteins revealed a banding pattern similar to those of patient sera. AVL appears to produce characteristic immunoblot patterns which can be used along with a sensitive screening ELISA to diagnose AVL.

The importance of the opossum (Didelphis albiventris) as a reservoir for Trypanosoma cruzi in Bambuí, Minas Gerais state

In a survey realized on the sylvatic and peridomestic environment at Bambuí county, Minas Gerais State, 44 (37.9%) out of 116 opossums (Didelphis albiventris) captured were found to be naturally infected with Trypanosoma cruzi. One handred and forty three parasite samples were obtanied from 43 infected opossums using simultaneously hemoculture, xenodiagnosis (Triatoma infestans, Panstrongylus megistus and Rhodnius neglectus) and examination of anal glands contents. The parasite samples were characterized according to six isoenzyme patterns. All samples, independently of the method of isolation, presented an isoenzyme pattern similar to the standard T. cruzi Z1, showing that either xenodiagnosis or hemoculture can used without selecting parasite subpopulation from naturally infected opossums. Preveous isoenzyme patterns reported for human T.cruzi isolates from same region were completely different. This isoenzyme dissimilarity between sylvatic and domiciliar environments suggests the existence of two independent T. cruzi transmission cycles in Bambuí. The epidemiological implicatinos of these results are discussed.

Antibody isotypes, including IgG subclasses, in Ecuadorian patients with pulmonary Paragonimiasis

An ELISA test was developed to detect Paragonimus-specific antibodies, including IgG subclasses, using P. mexicanus crude water-soluble antigens. The test was standardized to detect antibodies in sera of Ecuadorian patients with pulmonary paragonimiasis and negative controls from the endemic area. The detected mean levels of IgG (0.753, SEM: 0.074) and IgM (0.303, SEM: 0.033) were significantly elevated (P<0.05). Within the IgG subclasses, IgG4 showed the highest detected mean level (0.365, SEM: 0.116) and the other three subclasses showed considerably lower mean levels (IgG1, 0.186 SEM: 0.06; IgG2, 0.046 SEM: 0.01; IgG3, 0.123 SEM: 0.047). The number of P. mexicanus eggs found in sputum of infected individuals showed a positive correlation with the level of antibodies detected for IgM, IgG and its subclasses (P<0.001). The relevance of these findings in Ecuadorian patients suffering from pulmonary paragonimiasis is discussed.

Molecular Genetic Analysis of Multi-drug Resistance in Indian Isolates of Mycobacterium tuberculosis

A total of 116 isolates from patients attending the out-patient department at the All India Institute of Medical Sciences, New Delhi and the New Delhi Tuberculosis Centre, New Delhi, India were collected. They were analyzed for resistance to drugs prescribed in the treatment for tuberculosis. The drug resistance was initially determined by microbiological techniques. The Bactec 460TB system was employed to determine the type and level of resistance in each isolate. The isolates were further characterized at molecular level. The multi-drug loci corresponding to rpo b, gyr A, kat G were studied for mutation(s) by the polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) technique. The SSCP positive samples were sequenced to characterize the mutations in rpo b, and gyr A loci. While previously reported mutations in the gyr A and rpo b loci were found to be present, several novel mutations were also scored in the rpo b locus. Interestingly, analysis of the gyr A locus showed the presence of point mutation(s) that could not be detected by PCR-SSCP. Furthermore, rifampicin resistance was found to be an important marker for checking multi-drug resistance (MDR) in clinical isolates of Mycobacterium tuberculosis. This is the first report on molecular genetic analysis of MDR tuberculosis one from India, highlights the increasing incidence of MDR in the Indian isolates of M. tuberculosis.

Biology of Amblyomma aureolatum (Pallas, 1772) (Acari: Ixodidae) on some laboratory hosts in Brazil

The ixodid Amblyomma aureolatum is suspected to play a role in the epidemiology of wild life-cycle hemoparasites, which frequently infect dogs in rural and hunting areas in Brazil. Little is known about its bionomics. The objective of the present study was to evaluate some bionomic aspects of A. aureolatum ticks in Brazil. One engorged female, collected from a dog (Canis familiaris) in São Sebastião das Águas Claras, State of Minas Gerais, was used to establish a colony in the laboratory. Subsequently its parasitic stage progeny were fed on domestic dogs and laboratory animals. The free-living stages were incubated at 27ºC ± 2°C and minimum 70% relative humidity in a BOD incubator. The egg incubation period ranged from 31 to 34 days; the parasitic period of larvae ranged from 4 to 6 days and ecdysis to nymphs occurred from day 19 up to day 22. The parasitic period of nymphs ranged from 5 to 8 days and the period of ecdysis to adults from 31 to 33 days. The parasitic period of adults ranged from 11 to 15 days, the pre-oviposition period from 6 to 12 days, and the oviposition period from 9 to 38 days. The total duration of the life cycle ranged from 116 to 168 days.

Immunoblotting for the serodiagnosis of Helicobacter pylori infection in Brazilian patients with and without gastric carcinoma

We evaluated the performance of a commercial immunoblotting in the serodiagnosis of Helicobacter pylori infection in Brazilian patients. The presence of anti-H. pylori antibodies was also investigated in a group of 20 duodenal ulcer patients after successful treatment. One hundred and ninety one patients were studied. Among the 164 infected patients, 46 had gastric carcinoma. The duodenal ulcer patients were treated with antimicrobial drugs and the eradication of the microorganism was confirmed in all of them one month after the end of the treatment by the 13C-urea breath test. Sera were assayed for H. pylori antibodies using the Helicoblot 2.0 (Genelabs Diagnostics, Singapore). The sensitivity, specificity, positive, and negative predictive values of the test were 93.9%, 92.6%, 98.7%, and 71.4%, respectively. The sensitivity of the test was similar in patients with (93.5%) and without (95.7%) gastric carcinoma. Twenty-four months after the end of the treatment, the band of 116 kDa was still detected in one of the patients. In conclusion, the Helicoblot 2.0 is an accurate test to diagnose H. pylori infection and although it can not be employed to monitor the bacterium eradication, it may be useful for diagnosing past infection, especially in gastric carcinoma patients.

Chloroquine resistant Plasmodium falciparum malaria in Osogbo Nigeria: efficacy of amodiaquine + sulfadoxine-pyrimethamine and chloroquine + chlorpheniramine for treatment

Chloroquine (CQ) resistance in Plasmodium falciparum contributes to increasing malaria-attributable morbidity and mortality in Sub-Saharan Africa. Despite a change in drug policy, continued prescription of CQ did not abate. Therefore the therapeutic efficacy of CQ in uncomplicated falciparum malaria patients was assessed in a standard 28-day protocol in 116 children aged between six and 120 months in Osogbo, Southwest Nigeria. Parasitological and clinical assessments of response to treatment showed that 72 (62.1%) of the patients were cured and 44 (37.9%) failed the CQ treatment. High initial parasite density and young age were independent predictors for early treatment failure. Out of the 44 patients that failed CQ, 24 received amodiaquine + sulphadoxine/pyrimethamine (AQ+SP) and 20 received chlorpheniramine + chloroquine (CH+CQ) combinations. Mean fever clearance time in those treated with AQ+SP was not significantly different from those treated with CH+CQ (p = 0.05). There was no significant difference in the mean parasite density of the two groups. The cure rate for AQ+SP group was 92% while those of CH+CQ was 85%. There was a significant difference in parasite clearance time (p = 0.01) between the two groups. The 38% treatment failure for CQ reported in this study is higher than the 10% recommended by World Health Organization in other to effect change in antimalarial treatment policy. Hence we conclude that CQ can no more be solely relied upon for the treatment of falciparum malaria in Osogbo, Nigeria. AQ+SP and CH+CQ are effective in the treatment of acute uncomplicated malaria and may be considered as useful alternative drugs in the absence of artemisinin-based combination therapies.

Prevalence of antiretroviral drug resistance among treatment-naive and treated HIV-infected patients in Venezuela

An in-house, low-cost method was developed to determine the genotypic resistance of immunodeficiency virus type 1 (HIV-1) isolates. All 179 Venezuelan isolates analysed belonged to subtype B. Primary drug resistance mutations were found in 11% of 63 treatment-naïve patients. The prevalence of resistance in isolates from 116 HIV-positive patients under antiretroviral treatment was 47% to protease inhibitors, 65% to nucleoside inhibitors and 38% to non-nucleoside inhibitors, respectively. Around 50% of patients in the study harboured viruses with highly reduced susceptibility to the three classical types of drugs after only five years from their initial diagnoses.

Prevalence and genotyping of hepatitis C virus in blood donors in the state of Pará, Northern Brazil

Given the scarcity of epidemiological information on hepatitis C virus (HCV) infection in Northern Brazil, we determined the prevalence and genotypic frequency in blood donors in the state of Pará (PA). Blood samples from all of the blood donors at the Fundação HEMOPA (blood bank of PA) from 2004-2006 were screened for the presence of antibodies to anti-HCV and samples seroreactive to anti-HCV were further tested for HCV RNA using real-time PCR. In total, 116 HCV-RNA samples were genotyped, based on maximum likelihood phylogenetic analyses, using BioEdit, Modelgenerator, PHYML and FigTree software. The population consisted of 242,726 volunteers who donated blood from 2004-2006; the most common subgroup was males between the ages of 18-29 years old (37.30%). Within the whole group, 1,112 blood donors (0.46%) had indeterminate or positive serology; among these, 28.78% were males whose ages ranged from 18-29 years. A diagnosis of chronic HCV infection was confirmed for 304 donors (60.20% males; 66.45% were 30-49 years old), resulting in a prevalence of HCV RNA in 0.13% of the samples (304 of 242,726). HCV genotyping revealed a high frequency of genotype 1 (108/116) followed by genotype 3 (8/116). This study found HCV infection to be relatively infrequent in PA; genotype 1 was most commonly isolated. This information can help guide prevention and control policies aimed at efficient diagnosis and control measures.

Human polyomaviruses JC and BK in the urine of Brazilian children and adolescents vertically infected by HIV

The aim of this study was to characterize the urinary excretion of the BK (BKV) and JC (JCV) human polyomaviruses in a cohort of human immunodeficiency virus (HIV)-infected children and adolescents. One hundred and fifty-six patients were enrolled: Group I included 116 HIV-infected children and adolescents [median age = 11.4 years (y); range 1-22 y]; Group II included 40 non-HIV-infected healthy controls (median age = 11.37 y; range 7-16 y). Single urine samples from both groups were screened for the presence of JCV and BKV DNA by polymerase chain reaction at enrolment. The overall rate of JCV and BKV urinary excretion was found to be 24.4% and 40.4%, respectively (n = 156). Group I had urinary excretion of JCV and BKV in 27.6% and 54.3% of subjects, respectively. In contrast, Group II showed positive results for JCV in 17.5% of subjects and for BKV in 12.5% of subjects (p Pearson JCV = 0.20; p Pearson BKV < 0.0001). In Group I, there was no association between JCV/BKV shedding and age, gender or CD4 values. Patients with an HIV viral load < 50 copies/mL had a lower excretion of BKV (p < 0.001) and a trend of lower JCV excretion (p = 0.07). One patient in Group I (1/116, 0.9%) showed clinical and radiological features consistent with progressive multifocal leukoencephalopathy, suggesting that children with HIV/polyomavirus coinfection should be kept under surveillance.

Rapid tests for the detection of the Mycobacterium abscessus subsp. bolletii strain responsible for an epidemic of surgical-site infections in Brazil

A single strain of Mycobacterium abscessus subsp. bolletii, characterised by a particular rpoB sequevar and two highly related pulsed field gel electrophoresis patterns has been responsible for a nationwide outbreak of surgical infections in Brazil since 2004. In this study, we developed molecular tests based on polymerase chain reaction restriction-enzyme analysis (PRA) and sequencing for the rapid identification of this strain. Sequences of 15 DNA regions conserved in mycobacteria were retrieved from GenBank or sequenced and analysed in silico. Single nucleotide polymorphisms specific to the epidemic strain and located in enzyme recognition sites were detected in rpoB, the 3' region of the 16S rDNA and gyrB. The three tests that were developed, i.e., PRA-rpoB, PRA-16S and gyrB sequence analysis, showed 100%, 100% and 92.31% sensitivity and 93.06%, 90.28% and 100% specificity, respectively, for the discrimination of the surgical strain from other M. abscessus subsp. bolletii isolates, including 116 isolates from 95 patients, one environmental isolate and two type strains. The results of the three tests were stable, as shown by results obtained for different isolates from the same patient. In conclusion, due to the clinical and epidemiological importance of this strain, these tests could be implemented in reference laboratories for the rapid preliminary diagnosis and epidemiological surveillance of this epidemic strain.

Primary dengue virus infections induce differential cytokine production in Mexican patients

Severe dengue pathogenesis is not fully understood, but high levels of proinflammatory cytokines have been associated with dengue disease severity. In this study, the cytokine levels in 171 sera from Mexican patients with primary dengue fever (DF) and dengue haemorrhagic fever (DHF) from dengue virus (DENV) 1 (n = 116) or 2 (n = 55) were compared. DF and DHF were defined according to the patient’s clinical condition, the primary infections as indicated by IgG enzymatic immunoassay negative results, and the infecting serotype as assessed by real-time reverse transcription-polymerase chain reaction. Samples were analysed for circulating levels of interleukin (IL)-12p70, interferon (IFN)-γ, tumour necrosis factor (TNF)-α, IL-6, and IL-8 using a commercial cytometric bead array. Significantly higher IFN-γ levels were found in patients with DHF than those with DF. However, significantly higher IL-12p70, TNF-α, and IL-6 levels were associated with DHF only in patients who were infected with DENV2 but not with DENV1. Moreover, patients with DF who were infected with DENV1 showed higher levels of IL-12p70, TNF-α, and IL-6 than patients with DHF early after-fever onset. The IL-8 levels were similar in all cases regardless of the clinical condition or infection serotype. These results suggest that the association between high proinflammatory cytokine levels and dengue disease severity does not always stand, and it once again highlights the complex nature of DHF pathogenesis.