Co-infection and risk factors of tuberculosis in a Mexican HIV+ population

INTRODUCTION: The situation of tuberculosis (TB) is being modified by the human immunodeficiency virus (HIV), which is increasing the occurrence of new cases and the generation of drug resistant strains, affecting not only the people infected with HIV, but also their close contacts and the general population, conforming a serious public health concern. However, the magnitudes of the factors associated to this co-infection differ considerably in relation to the population groups and geographical areas. METHODS: In order to evaluate the prevalence and risk factors for the co-infection of tuberculosis (TB) in a population with human immunodeficiency virus (HIV+) in the Southeast of Mexico, we made the analysis of clinical and epidemiological variables and the diagnosis of tuberculosis by isolation of mycobacteria from respiratory samples. RESULTS: From the 147 HIV+ individuals analyzed, 12 were culture positive; this shows a prevalence of 8% for the co-infection. The only variable found with statistical significance for the co-infection was the number of CD4-T < 200 cells/mm³, OR 13 (95%, CI 2-106 vs 12-109). CONCLUSIONS: To our knowledge this is the first report describing the factors associated with tuberculosis co -infection with HIV in a population from Southern Mexico. The low number of CD4 T-cells was the only variable associated with the TB co-infection and the rest of the variables provide scenarios that require specific and particular interventions for this population group.

Diagnosis of human herpesvirus 6B primary infection by polymerase chain reaction in young children with exanthematic disease

INTRODUCTION: Exanthem subitum is a classical rash disease of early childhood caused by human herpesvirus 6B (HHV-6B). However, the rash is frequently misdiagnosed as that of either measles or rubella. METHODS: In this study, a nested multiplex polymerase chain reaction (PCR) was used to diagnose HHV-6B primary infection, differentiate it from infections caused by HHV-6A and compare it to antibody avidity tests. The samples were separated into case group and control group according to the results of the indirect immunofluorescence assay (IFA) technique. RESULTS: From the saliva samples analyzed, HHV-6A DNA was detected in 3.2% of the case group and in 2.6% of the control group. Regarding HHV-6B, PCR detected viral DNA in 4.8% of the case group and in 1.3% of the control group. Among the serum samples studied, a frequency of 1.7% was determined for HHV-6A in the case group and 1.2% in the control group. PCR did not detect HHV-6B DNA in serum samples. The sensitivity and specificity of the PCR technique ranged from 0% to 4.8% and 97.5% to 100%, respectively, compared to IFA. CONCLUSIONS: The PCR technique was not suitable for diagnosing primary infection by HHV-6B in children with exanthematic disease and should not substitute the IFA.

Study of infection by Rickettsiae of the spotted fever group in humans and ticks in an urban park located in the City of Londrina, State of Paraná, Brazil

INTRODUCTION: Spotted fevers are emerging zoonoses caused by Rickettsia species in the spotted fever group (SFG). Rickettsia rickettsii is the main etiologic agent of Brazilian spotted fever (BSF) and it is transmitted by Amblyomma spp. ticks. METHODS: The study aimed to investigate SFG rickettsiae in the Arthur Thomas Municipal Park in Londrina, PR, by collecting free-living ticks and ticks from capybaras and blood samples from personnel working in these areas. Samples from A. dubitatum and A. cajennense were submitted for PCR in pools to analyze the Rickettsia spp. gltA (citrate synthase gene). RESULTS: All the pools analyzed were negative. Human sera were tested by indirect immunofluorescence assay with R. rickettsii and R. parkeri as antigens. Among the 34 sera analyzed, seven (20.6%) were reactive for R. rickettsii: four of these had endpoint titers equal to 64, 2 titers were 128 and 1 titer was 256. None of the samples were reactive for R. parkeri. An epidemiological questionnaire was applied to the park staff, but no statistically significant associations were identified. CONCLUSIONS: The serological studies suggest the presence of Rickettsiae related to SFG that could be infecting the human population studied; however, analysis of the ticks collected was unable to determine which species may be involved in transmission to humans.

Improvement of a PCR test to diagnose infection by Mansonella ozzardi

INTRODUCTION: Mansonelliasis is caused by Mansonella ozzardi. It is widespread in the Amazon region, with a high prevalence. The common exam of thick blood smears stained with Giemsa shows low efficacy levels and has been an obstacle to diagnosing individuals with low blood parasitemia. METHODS: In order to increase diagnosis efficacy, the PCR technique was improved. RESULTS AND CONCLUSIONS: PCR demonstrated the best performance, with sensitivity and negative predictive values (NPV) of 100%, followed by blood filtration through membrane filters, which showed a sensitivity of 88.9% and a NPV of 84.6%, when compared to thick blood smears.

Nosocomial infection and characterization of extended-spectrum β-lactamases-producing Enterobacteriaceae in Northeast Brazil

INTRODUCTION: Extended spectrum β-lactamases (ESBLs) are enzymes that degrade β-lactam antibiotics and have been reported to be an important cause of nosocomial infection in worldwide. METHODS: During 2009, 659 enterobacteria strains were isolated from different clinical specimens and tested for ESBL production. The disk approximation test, combined disk method and addition of clavulanic acid were used for phenotypic detection of the ESBL-producing strains and PCR for detection of the blaTEM and blaCTX-M genes. RESULTS: Among the isolates, 125 were ESBL producers. The blaCTX-M and blaTEM genes were detected in 90.4% and 75% of the strains, respectively. Most strains were isolated from urine. Klebsiella pneumoniae was the most prevalent organism. Microorganisms presented high resistance to the antibiotics. CONCLUSIONS: These results support the need for extending ESBL detection methods to different pathogens of the Enterobacteriaceae family because these methods are only currently standardized by the CLSI for Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca and Proteus mirabilis. Carbapenems were the antibiotic class of choice for the treatment of infections caused by ESBL-producing Enterobacteriaceae.

Mother-to-child transmission of HIV infection in Manaus, State of Amazonas, Brazil

INTRODUCTION: Reduction in the vertical transmission of HIV is possible when prophylactic measures are implemented. Our objective was to determine demographic characteristics of HIV-infected pregnant women and the rate of mother-to-child transmission of HIV in Manaus, Amazonas, Brazil. METHODS: A descriptive study was conducted using notification, and investigating data from the Notifiable Diseases Data System in the Brazilian State of Amazonas, between 2007 and 2009. RESULTS: During the study period, notification was received of 509 HIV-positive pregnant women. The vertical transmission was 9.9% (95% CI: 7.2-12.6%). The mean age of women was 27 years (SD: 5.7), and the majority (54.8%) had not completed elementary school (eighth grade). Diagnosis of HIV seropositivity was made prior to pregnancy in 115 (22.6%) women, during prenatal care in 302 (59.3%), during delivery in 70 (13.8%), and following delivery in 22 (4.3%). Four hundred four of these women (79.4%) had had prenatal care, with 79.4% of patients receiving antiretroviral during pregnancy and 61.9% of the newborn infants receiving prophylaxis. In the final multivariate logistic regression model, living in urban area [OR = 0.7 (95% CI: 0.35-0.89)] and having had prenatal care [OR = 0.1 (95% CI: 0.04-0.24)] remained as protective factors against vertical HIV transmission in this population. CONCLUSIONS: The relevance of adequate compliance with the measures already established as being effective in guaranteeing a reduction in HIV transmission within the maternal and infant population should be emphasized.

Hepatitis B and C virus infection among Brazilian Amazon riparians

INTRODUCTION: Viral hepatitis is a major public health concern in Brazil. There are few past studies on this issue, especially among riparian communities. This study aims at determining the seroprevalence of viral hepatitis B and C in the riparian community of Pacuí Island, within the Cametá municipality of Pará State, Brazil. Moreover, this study aims to investigate the principal risk factors that this community is exposed to. METHODS: The current study has accessed blood samples from 181 volunteers who have answered an epidemiological questionnaire. Analyses on serological markers have been tested with commercial ELISA kits for detecting HBsAg, total anti-HBc, anti-HBs, and anti-HCV. Within seroreactive patients for HCV, RT-PCR and line probe assay have been performed to identify the viral genotype. RESULTS: In the serological marker analysis for hepatitis B, no reactivity for HBsAg, rate of 1.1% for total anti-HBc, and rate of 19.3% for anti-HBs have been observed. On hepatitis C, 8.8% seroprevalence has been found, in which 62.5% have gotten viral RNA. Among the risk factors studied, the following have been highlighted: non-use of condoms, sharing of cutting instruments, use of illicit drugs, and reports of family disease with HBV or HCV. CONCLUSIONS: The vaccination coverage against HBV is low, and the high prevalence of HCV within this community has been observed.

A Natural Protective Mechanism Against Malaria

Malaria is an infectious disease of humans and other animals including birds, reptiles and most mammals. It is transmitted via the inoculation of Plasmodium sporozoites into the skin through the bite of an infected female Anopheles mosquito. Although every year, around 700.000 lives are perished, mainly children under the age of 3-5 years old, to Plasmodium infection this deadly parasite has a relatively low efficiency of transmission from mosquitoes into humans.(...)

Host genetic factors in mouse malaria liver stage infection

Fundação para a Ciência e a Tecnologia

Co-infection Trypanosoma cruzi/HIV: systematic review (1980 - 2010)

INTRODUCTION: The co-infection Trypanosoma cruzi/HIV has been described as a clinical event of great relevance. The objective of this study wasto describe clinical and epidemiological aspects published in literature. METHODS: It is a systematic review of a descriptive nature from the databases Medline, Lilacs, SciELO, Scopus, from 1980 to 2010. RESULTS: There were 83 articles (2.8 articles/year) with a total of 291 cases. The co-infection was described in 1980 and this situation has become the defining AIDS clinical event in Brazil. This is the country with the highest number of publication (51.8%) followed by Argentina (27.7%). The majority of cases are amongst adult men (65.3%) native or from endemic regions with serological diagnosis in the chronic stage (97.9%) and indeterminate form (50.8%). Both diseases follow the normal course, but in 41% the reactivation of the Chagas disease occurs. The most severe form is the meningoencephalitis, with 100% of mortality without specific and early treatment of the T. cruzi. The medication of choice was the benznidazole on doses and duration normally used for the acute phase. The high parasitemia detected by direct or indirect quantitative methods indicated reactivation and its elevation is the most important predictive factor. The lower survival rate was related to the reactivation of the Chagas disease and the natural complications of both diseases. The role of the antiretroviral treatment on the co-infection cannot yet be defined by the knowledge currently existent. CONCLUSIONS: Despite the relevance of this clinical event there are still gaps to be filled.

Prevalence of hepatitis B virus infection and carriage after nineteen years of vaccination program in the Western Brazilian Amazon

INTRODUCTION: Reductions in the prevalence of hepatitis B virus (HBV) infection and carriage, decreases in liver cancer incidence, and changes in patterns of liver dysfunctions are described after hepatitis B vaccination. METHODS: We conducted a population-based seroprevalence study aimed at estimating the HBV prevalence and risk of infection in the rural area of Lábrea following nineteen years of HBV vaccination. RESULTS: Half of the subjects showed total anti-HBc of 52.1% (95% CI 49.6-54.7). The HBsAg prevalence was 6.2% (95% CI 5.1-7.6). Multivariate analysis showed an inverse association between HBV infection and vaccination (OR 0.62; 95% CI 0.44-0.87). HBsAg remained independently associated with past hepatitis (OR 2.44; 95% CI 1.52-3.89) and inversely to vaccination (OR 0.43; 95% CI 0.27-0.69). The prevalence of HBeAg among HBsAg-positive individuals was 20.4% (95% CI 12.8-30.1), with the positive subjects having a median age of 11 years (1-46) p=0.0003. CONCLUSIONS: We demonstrate that HBV infection is still an important public health issue and that HBV vaccination could have had better impact on HBV epidemiology. If we extrapolate these findings to other rural areas in the Brazilian Amazon, we can predict that the sources of chronic infected patients remain a challenge. Future studies are needed regarding clinical aspects, molecular epidemiology, surveillance of acute cases, and risk groups.

Diagnosis of Leishmania (Leishmania) chagasi infection in dogs and the relationship with environmental and sanitary aspects in the municipality of Palmas, state of Tocantins, Brazil

INTRODUCTION: The aim of the present study was to identify the presence of Leishmania (Leishmania) chagasi infection in dogs in the City of Palmas, Tocantins, Brazil, using the PCR technique to list the hot spots of infected dogs in the city and associate their occurrence to significant environmental changes at capture sites. METHODS: DNA was extracted from blood of dogs, and the PCR were performed with primers RV1/RV2. After screening the population studied, the regions of the city that had the highest occurrence of canine infection were detected. These sites were visited, and ecological parameters denoting anthropogenic disturbance were evaluated. RESULTS: Some important features were listed in the regions visited, such as low urbanization, lack of public collection of sewage, limited garbage collection, vacant lots with tall vegetation, decaying organic matter, and, most importantly, the occurrence of stray dogs and poultry in homes. CONCLUSIONS: The methodology for screening the population was very efficient, especially in evaluating a large number of individuals in a short time, with a high degree of automation. The results indicate an association between the observed parameters and the occurrence of infection in dogs. The model presented in the city is ideal for studies of disease progression and expansion and for the evaluation of control measures adopted for canine VL.

Production of cytokine and chemokines by human mononuclear cells and whole blood cells after infection with Trypanosoma cruzi

INTRODUCTION: The innate immune response is the first mechanism of protection against Trypanosoma cruzi, and the interaction of inflammatory cells with parasite molecules may activate this response and modulate the adaptive immune system. This study aimed to analyze the levels of cytokines and chemokines synthesized by the whole blood cells (WBC) and peripheral blood mononuclear cells (PBMC) of individuals seronegative for Chagas disease after interaction with live T. cruzi trypomastigotes. METHODS: IL-12, IL-10, TNF-α, TGF-β, CCL-5, CCL-2, CCL-3, and CXCL-9 were measured by ELISA. Nitrite was determined by the Griess method. RESULTS: IL-10 was produced at high levels by WBC compared with PBMC, even after incubation with live trypomastigotes. Production of TNF-α by both PBMC and WBC was significantly higher after stimulation with trypomastigotes. Only PBMC produced significantly higher levels of IL-12 after parasite stimulation. Stimulation of cultures with trypomastigotes induced an increase of CXCL-9 levels produced by WBC. Nitrite levels produced by PBMC increased after the addition of parasites to the culture. CONCLUSIONS: Surface molecules of T. cruzi may induce the production of cytokines and chemokines by cells of the innate immune system through the activation of specific receptors not evaluated in this experiment. The ability to induce IL-12 and TNF-α contributes to shift the adaptive response towards a Th1 profile.