Dynamics of Hepatitis D (delta) virus genotype 3 in the Amazon region of South America

Hepatitis delta virus (HDV) is widely distributed and associated with fulminant hepatitis epidemics in areas with high prevalence of HBV. Several studies performed in the 1980s showed data on HDV infection in South America, but there are no studies on the viral dynamics of this virus. The aim of this study was to conduct an evolutionary analysis of hepatitis delta genotype 3 (HDV/3) prevalent in South America: estimate its nucleotide substitution rate, determine the time of most recent ancestor (TMRCA) and characterize the epidemic history and evolutionary dynamics. Furthermore, we characterized the presence of HBV/HDV infection in seven samples collected from patients who died due to fulminant hepatitis from Amazon region in Colombia and included them in the evolutionary analysis. This is the first study reporting HBV and HDV sequences from the Amazon region of Colombia. Of the seven Colombian patients, five were positive for HBV-DNA and HDV-RNA. Of them, two samples were successfully sequenced for HBV (subgenotypes F3 and Fib) and the five samples HDV positive were classified as HDV/3. By using all HDV/3 available reference sequences with sampling dates (n = 36), we estimated the HDV/3 substitution rate in 1.07 x 10(-3) substitutions per site per year (s/s/y), which resulted in a time to the most recent common ancestor (TMRCA) of 85 years. Also, it was determined that HDV/3 spread exponentially from early 1950s to the 1970s in South America. This work discusses for the first time the viral dynamics for the HDV/3 circulating in South America. We suggest that the measures implemented to control HBV transmission resulted in the control of HDV/3 spreading in South America, especially after the important raise in this infection associated with a huge mortality during the 1950s up to the 1970s. The differences found among HDV/3 and the other HDV genotypes concerning its diversity raises the hypothesis of a different origin and/or a different transmission route. (C) 2011 Elsevier B.V. All rights reserved.

International study of temperature, heat and urban mortality: the `ISOTHURM` project

Background This study describes heat- and cold-related mortality in 12 urban populations in low- and middle-income countries, thereby extending knowledge of how diverse populations, in non-OECD countries, respond to temperature extremes. Methods The cities were: Delhi, Monterrey, Mexico City, Chiang Mai, Bangkok, Salvador, So Paulo, Santiago, Cape Town, Ljubljana, Bucharest and Sofia. For each city, daily mortality was examined in relation to ambient temperature using autoregressive Poisson models (2- to 5-year series) adjusted for season, relative humidity, air pollution, day of week and public holidays. Results Most cities showed a U-shaped temperature-mortality relationship, with clear evidence of increasing death rates at colder temperatures in all cities except Ljubljana, Salvador and Delhi and with increasing heat in all cities except Chiang Mai and Cape Town. Estimates of the temperature threshold below which cold-related mortality began to increase ranged from 15 degrees C to 29 degrees C; the threshold for heat-related deaths ranged from 16 degrees C to 31C. Heat thresholds were generally higher in cities with warmer climates, while cold thresholds were unrelated to climate. Conclusions Urban populations, in diverse geographic settings, experience increases in mortality due to both high and low temperatures. The effects of heat and cold vary depending on climate and non-climate factors such as the population disease profile and age structure. Although such populations will undergo some adaptation to increasing temperatures, many are likely to have substantial vulnerability to climate change. Additional research is needed to elucidate vulnerability within populations.

AIDS in Latin America: assessing the current status of the epidemic and the ongoing response

Background This article provides a summary of the current status of the HIV/AIDS epidemic in Latin America, as well as an outline of the diverse responses to it. Methods A search of international databases (Pubmed and ISI-Web of Science), regional databases (Scielo and Lilacs), regional and national documents and UNAIDS reports. Data are presented according to subregion. Results In Mexico HIV remains concentrated among urban men who have sex with men (MSM), and has been growing among injecting drug users (IDU) and in rural areas in relation to migration. An increasing proportion of women among those affected is observed in all countries in Central America, the most affected region, as well as increasing the impact on other vulnerable groups, such as indigenous populations. The Andean Countries have urban epidemics concentrated among MSM. In Peru, non-traditional vulnerable populations were identified. In the Southern Cone heterosexual transmission became more relevant, probably in connection with IDU epidemics and is increasingly affecting lower income groups. Incidence rates have been declining since 2002 in Brazil, the first country to guarantee free, universal access to antiretrovirals, where one-third of drug-nave patients are still initiating treatment at an advanced stage. Generally, access to treatment has improved as a result of support from the Global Fund and other initiatives, but there are concerns regarding coverage, equity and sustainability. Conclusions HIV is still concentrated among MSM in Latin America. Non-traditional vulnerable groups such as migrants and lower income populations, usually considered part of the general population, deserve attention. Programmes confronting sexual exclusion are still needed. Access to treatment has improved over time, but inequalities persist.

Modelling the control strategies against dengue in Singapore

Notified cases of dengue infections in Singapore reached historical highs in 2004 (9459 cases) and 2005 (13 817 cases) and the reason for such all increase is still to be established. We apply a mathematical model for dengue infection that takes into account the seasonal variation in incidence, characteristic of dengue fever, and which mimics the 2004-2005 epidemics in Singapore. We simulated a set of possible control strategies and confirmed the intuitive belief that killing adult mosquitoes is the most effective strategy to control an ongoing epidemic. On the other hand, the control of immature forms was very efficient ill preventing the resurgence of dengue epidemics. Since the control of immature forms allows the reduction of adulticide, it seems that the best strategy is to combine both adulticide and larvicide control measures during an outbreak, followed by the maintenance of larvicide methods after the epidemic has subsided. In addition, the model showed that the mixed strategy of adulticide and larvicide methods introduced by the government seems to be very effective in reducing the number of cases in the first weeks after the start of control.

Response to AIDS in Brazil: contributions of social movements and the sanitary reform

This paper briefly outlines how the political scenario and the mobilization of different actors have contributed to the construction of a public health policy in response to the AIDS epidemics in Brazil. Three factors are presented and discussed: the political context of the 1980s, characterized by redemocratization, growth of social movements, and consolidation of the Brazilian health care reform; the socio-cultural context of the 1970s and 1980s, characterized by achievement of individual freedom, which was key to the organization of the AIDS movement; and finally the actions carried out in the international scenario to support the sustainability of the Brazilian domestic policy and the reinforcement of a global response to face the epidemics in lower-middle income economies.

Impact of PI and NNRTI HAART-based therapy on oral lesions of Brazilian HIV-infected patients

Background: The incidence of oral lesions related to human immunodeficiency virus (HIV) infection have been investigated after treatment with highly active antiretroviral therapy (HAART) including protease inhibitors (PI) but no data are available on the effect of non-nucleoside reverse transcriptase inhibitor (NNRTI)-based therapy on incidence of acquired immunodeficiency syndrome (AIDS) oral manifestations or impact of HAART on oral manifestations of HIV infection in Brazil. The aim of this study was to describe the effects of anti-HIV therapy on the incidence of oral lesions during 17 years of AIDS epidemics in a Brazilian population. Methods: From 1989 to 2006, we collected data from 1595 consecutive HIV patients at the Special Care Dentistry Center, Sao Paulo, Brazil. We compared the effect of PI- and NNRTI-based antiretroviral therapy (ARVT) on the annual incidence of Kaposi sarcoma (KS), oral candidiasis (OC) and hairy leukoplakia (HL). The chi-squared test was used to test the association between oral lesions and therapeutic regimen (P < 0.05). Results: None of patients on ARVT presented with KS. Patients who used (nucleoside reverse transcriptase inhibitors) NRTI + PI were 0.9 times as likely to present with HL as those who used NRTI + NNRTI. This finding, however, was not statistically significant (P = 0.5). The relative risk for OC was 0.8 in patients with PI-based HAART. The increased risk among those on PIs was statistically significant (P = 0.004). Conclusions: The superiority of NNRTI regimens in decreasing OC incidence is consistent with current therapeutic guidelines which recommend NNRTI-based therapy as the treatment of choice for initial ARVT.

The relationship of a clonal outbreak of Enterococcus faecium vanA to methicillin-resistant Staphylococcus aureus incidence in an Australian hospital

Australian isolates of vancomycin-resistant enterococci (VRE) have been widely scattered geographically, predominantly polyclonal and of the VanB phenotype. Forty-nine VRE were isolated from 47 patients in our hospital from October 1996 to December 1999. Forty-four of these VRE were Enterococcus faecium with a vanA glycopeptide resistance genotype. Four isolates were pathogenic. Thirty-five VRE were from an outbreak in the Renal and Infectious Diseases Units over a four-month period. Pulsed-field gel electrophoresis (PFGE) demonstrated that 41 of the 49 VRE were indistinguishable or closely related. Enhanced environmental cleaning, strict contact isolation of colonized patients and reducing inpatient admissions terminated the epidemic. Cohorting of methicillin-resistant Staphylococcus aureus (MRSA)-positive patients was restricted because VPE patients occupied the isolation facilities. This resulted in a statistically significant increase in MRSA infections across the hospital. VRE epidemics have the ability to influence the epidemiology of other nosocomial pathogens when infection control resources are exhausted. (C) 2001 The Hospital Infection Society.

Antibody-dependent enhancement of Murray Valley encephalitis virus virulence in mice

Enhancement of flavivirus infection in vitro in the presence of subneutralizing concentrations of homologous or heterologous antiserum has been well described. However, the importance of this phenomenon in the enhancement of flavivirus infection in vivo has not been established. In order to study antibody- mediated enhancement of flavivirus infection in vivo, we investigated the effect of passive immunization of mice with Japanese encephalitis virus (JE) antiserum on the outcome of infection with Murray Valley encephalitis virus (MVE). We show that prior treatment of mice with subneutralizing concentrations of heterologous JE antiserum resulted in an increase in viraemia titres and in mortality following challenge with wild-type MVE. Our findings support the hypothesis that subneutralizing concentrations of antibody may enhance flavivirus infection and virulence in vivo. These findings are of potential importance for the design of JE vaccination programs in geographic areas in which MVE co-circulates. Should subneutralizing concentrations of antibody remain in the population following JE vaccination, it is possible that enhanced disease may be observed during MVE epidemics.

Potential role of head lice, Pediculus humanus capitis, as vectors of Rickettsia prowazekii

Since the pioneering work of Charles Nicolle in 1909 [see Gross (1996) Proc Natl Acad Sci USA 93:10539-10540] most medical officers and scientists have assumed that body lice are the sole vectors of Rickettsia prowazekii, the aetiological agent of louse-borne epidemic typhus (LBET). Here we review the evidence for the axiom that head lice are not involved in epidemics of LBET. Laboratory experiments demonstrate the ability of head lice to transmit R. prowazekii, but evidence for this in the field has not been reported. However, the assumption that head lice do not transmit R. prowazekii has meant that head lice have not been examined for R. prowazekii during epidemics of LBET. The strong association between obvious (high) infestations of body lice and LBET has contributed to this perception, but this association does not preclude head lice as vectors of R. prowazekii. Indeed, where the prevalence and intensity of body louse infections may be high (e.g. during epidemics of LBET), the prevalence and intensity of head louse infestations is generally high as well. This review of the epidemiology of head louse and body louse infestations, and of LBET, indicates that head lice are potential vectors of R. prowazekii in the field. Simple observations in the field would reveal whether or not head lice are natural vectors of this major human pathogen.

Studies on mosquitoes (Diptera: Culicidae) and anthropic environment: 9- Synanthropy and epidemiological vector role of Aedes scapularis in South-Eastern Brazil

Behaviour comparisons of Aedes scapularis and Ae. serratus are presented. Results were obtained by sampling Aedes adult mosquitoes at several places in the rural anthropic environment in the Ribeira Valley region of S. Paulo State, Brazil. Aedes dominance was shared by those two species, but Ae. scapularis Sshowed a clear tendency to frequent the modified environment, while Ae. serratus was to be found in the more preserved ones, here represented by the vestigial patchy forests. Regarding the open cultivated land and the dwelling environments, Ae. scapularis preponderates. Considering the regional developmental phases, this mosquito showed a remarkable increase in the modified environment differently from Ae. serratus that underwent a considerable decrease in migrating from the forest to the anthropic environment. As a consequence of these results it is reasonable to conclude that Ae. scapularis may be considered as an epidemiologically efficient vector and that it quite probably played this role in the Rocio encephalitis and other arbovirus epidemics.

Control of Aedes aegypti with temephos in a Buenos Aires cemetery, Argentina

The efficacy of a larvicide, temephos, for controlling Ae. aegypti was evaluated in a cemetery in Buenos Aires, Argentina. Breeding sites decreased from 18.4% in the first study period (Nov 1998 to May 1999, without temephos) to 2.2% in the second period (Nov 1999 to May 2000, two applications), and to 0.05% in the third one (Nov 2000 to May 2001, five applications). Ovitraps with eggs decreased from 17% in the first period to 5.8% in the second period, and to 2.9% in the third one. Results suggest that, in Buenos Aires, Ae. aegypti populations are highly susceptible to temephos. It is recommended to limit the use of temephos to prevent potential epidemics rather than for routine control.

Sensors for the detection and quantification of bacterial contamination in water for human use

The deterioration of water quality by Cyanobacteria cause outbreaks and epidemics associated with harmful diseases in Humans and animals because of the toxins that they release. Microcystin-LR is one of the hepatotoxins most widely studied and the World Health Organization, recommend a maximum value of 1mgL 1 in drinking water. Highly specific recognition molecules, such as molecular imprinted polymers are developed to quantify microcystins in waters for human use and shown to be of great potential in the analysis of these kinds of samples. The obtained results were auspicious, the detection limit found, 1.5mgL 1, being of the same order of magnitude as the guideline limit recommended by the WHO. This technology is very promising because the sensors are stable and specific, and the technology is inexpensive and allows for rapid on-site monitoring.

Evaluation of dengue fever reports during an epidemic, Colombia

OBJECTIVE To assess the validity of dengue fever reports and how they relate to the definition of case and severity. METHODS Diagnostic test assessment was conducted using cross-sectional sampling from a universe of 13,873 patients treated during the fifth epidemiological period in health institutions from 11 Colombian departments in 2013. The test under analyses was the reporting to the National Public Health Surveillance System, and the reference standard was the review of histories identified by active institutional search. We reviewed all histories of patients diagnosed with dengue fever, as well as a random sample of patients with febrile syndromes. The specificity and sensitivity of reports were estimated for this purpose, considering the inverse of the probability of being selected for weighting. The concordance between reporting and the findings of the active institutional search was calculated using Kappa statistics. RESULTS We included 4,359 febrile patients, and 31.7% were classified as compatible with dengue fever (17 with severe dengue fever; 461 with dengue fever and warning signs; 904 with dengue fever and no warning signs). The global sensitivity of reports was 13.2% (95%CI 10.9;15.4) and specificity was 98.4% (95%CI 97.9;98.9). Sensitivity varied according to severity: 12.1% (95%CI 9.3;14.8) for patients presenting dengue fever with no warning signs; 14.5% (95%CI 10.6;18.4) for those presenting dengue fever with warning signs, and 40.0% (95%CI 9.6;70.4) for those with severe dengue fever. Concordance between reporting and the findings of the active institutional search resulted in a Kappa of 10.1%. CONCLUSIONS Low concordance was observed between reporting and the review of clinical histories, which was associated with the low reporting of dengue fever compatible cases, especially milder cases.

The 1853-1856 cholera morbus epidemic in Portugal as seen by the press

This research is part of a larger project focused on producing a History of the Popularization of Science and Technology in Portugal. The goal is to find out how scientific knowledge reached the common people in the nineteenth century, using newspapers as the main source of information. Keeping in mind the population’s limited access to written material, nevertheless each newspaper could be read daily by an estimate 30.000 people in Lisbon, which places this source as probably the most widespread vehicle to divulge the latest scientific news at the time to an unspecialised audience. With a cholera morbus epidemic which affected the second largest Portuguese town and all the northern regions, as well as the Algarve, news and reports on its evolution were considered essential. A large database was built in order to analyse the news concerning this disease in 1855 and 1856, especially the ones about prevention and treatment. These are important historical sources that give us real information on the scientific knowledge of the time and the way it was used by society.