Biodiversity Can Help Prevent Malaria Outbreaks in Tropical Forests

Background: Plasmodium vivax is a widely distributed, neglected parasite that can cause malaria and death in tropical areas. It is associated with an estimated 80-300 million cases of malaria worldwide. Brazilian tropical rain forests encompass host- and vector-rich communities, in which two hypothetical mechanisms could play a role in the dynamics of malaria transmission. The first mechanism is the dilution effect caused by presence of wild warm-blooded animals, which can act as dead-end hosts to Plasmodium parasites. The second is diffuse mosquito vector competition, in which vector and non-vector mosquito species compete for blood feeding upon a defensive host. Considering that the World Health Organization Malaria Eradication Research Agenda calls for novel strategies to eliminate malaria transmission locally, we used mathematical modeling to assess those two mechanisms in a pristine tropical rain forest, where the primary vector is present but malaria is absent. Methodology/Principal Findings: The Ross-Macdonald model and a biodiversity-oriented model were parameterized using newly collected data and data from the literature. The basic reproduction number (R0) estimated employing Ross-Macdonald model indicated that malaria cases occur in the study location. However, no malaria cases have been reported since 1980. In contrast, the biodiversity-oriented model corroborated the absence of malaria transmission. In addition, the diffuse competition mechanism was negatively correlated with the risk of malaria transmission, which suggests a protective effect provided by the forest ecosystem. There is a non-linear, unimodal correlation between the mechanism of dead-end transmission of parasites and the risk of malaria transmission, suggesting a protective effect only under certain circumstances (e.g., a high abundance of wild warm-blooded animals). Conclusions/Significance: To achieve biological conservation and to eliminate Plasmodium parasites in human populations, the World Health Organization Malaria Eradication Research Agenda should take biodiversity issues into consideration. © 2013 Laporta et al.

Life cycle complexity, environmental change and the emerging status of salmonid proliferative kidney disease

P>1. Proliferative kidney disease (PKD) is a disease of salmonid fish caused by the endoparasitic myxozoan, Tetracapsuloides bryosalmonae, which uses freshwater bryozoans as primary hosts. Clinical PKD is characterised by a temperature-dependent proliferative and inflammatory response to parasite stages in the kidney.;2. Evidence that PKD is an emerging disease includes outbreaks in new regions, declines in Swiss brown trout populations and the adoption of expensive practices by fish farms to reduce heavy losses. Disease-related mortality in wild fish populations is almost certainly underestimated because of e.g. oversight, scavenging by wild animals, misdiagnosis and fish stocking.;3. PKD prevalences are spatially and temporally variable, range from 0 to 90-100% and are typically highest in juvenile fish.;4. Laboratory and field studies demonstrate that (i) increasing temperatures enhance disease prevalence, severity and distribution and PKD-related mortality; (ii) eutrophication may promote outbreaks. Both bryozoans and T. bryosalmonae stages in bryozoans undergo temperature- and nutrient-driven proliferation.;5. Tetracapsuloides bryosalmonae is likely to achieve persistent infection of highly clonal bryozoan hosts through vertical transmission, low virulence and host condition-dependent cycling between covert and overt infections. Exploitation of fish hosts entails massive proliferation and spore production by stages that escape the immune response. Many aspects of the parasite's life cycle remain obscure. If infectious stages are produced in all hosts then the complex life cycle includes multiple transmission routes.;6. Patterns of disease outbreaks suggest that background, subclinical infections exist under normal environmental conditions. When conditions change, outbreaks may then occur in regions where infection was hitherto unsuspected.;7. Environmental change is likely to cause PKD outbreaks in more northerly regions as warmer temperatures promote disease development, enhance bryozoan biomass and increase spore production, but may also reduce the geographical range of this unique multihost-parasite system. Coevolutionary dynamics resulting from host-parasite interactions that maximise fitness in previous environments may pose problems for sustainability, particularly in view of extensive declines in salmonid populations and degradation of many freshwater habitats.

Detection of Clostridium perfringens type C in pig herds following disease outbreak and subsequent vaccination

Immunisation of sows using Clostridium perfringens type C toxoid vaccines is recommended to prevent necrotising enteritis (NE) on pig breeding farms. Absence of disease, however, oftentimes leads to the false assumption of pathogens being eradicated. The prevalence of C perfringens type C was determined by PCR in faecal samples of piglets and sows in three Swiss pig breeding farms two to four years after implementation of a vaccination programme following disease outbreaks. C perfringens type C could still be detected several years after an outbreak despite absence of NE. In-herd prevalence of the pathogens varied significantly between the farms and was also lower compared with a farm which experienced a recent outbreak. In conclusion, C perfringens type C can be detected on once-affected farms, even in the absence of NE for several years.

Assessing maintenance of evaporative cooling systems in Legionellosis outbreaks

Evaporative cooling systems continue to be associated with outbreaks of Legionnaires’ disease despite widely available maintenance guidelines intended to reduce these outbreaks. Yet, the guidelines vary widely regarding the recommendations that are made to maintain evaporative cooling systems and it is unclear whether guidelines were in place or, if they were, whether they were being followed when the outbreaks of Legionnaires’ disease occurred. Thus, this study was designed to conduct two systematic reviews of (1) evaporative cooling system maintenance guidelines; and (2) published Legionnaires’ disease outbreaks. For each maintenance guideline identified in the systematic review, recommended maintenance practices were abstracted and similarities and/or differences in the reported recommendations were assessed. Following the systematic review of outbreak investigations that meet the inclusion criteria established for the study, information about the state of the evaporative cooling system during the outbreak investigation was abstracted to summarize, when reported, which maintenance practices were implemented. As expected, the recommended maintenance procedures varied greatly across the guidelines and were not always specific. Overall, the outbreak investigations tended to report similar maintenance issues that were unclear in the maintenance guidelines. Generally, these maintenance issues were biocide use, microbiological testing, frequency of general inspections, and protocols and frequency of total system cleanings. The role in which non-standardized and generalized maintenance guidelines plays in the continued association between Legionnaires’ disease and evaporative cooling systems is still not fully understood. However, this study suggests that more specific and standardized maintenance guidelines, that have been scientifically established to be effective in controlling Legionella bacteria, are needed and then these guidelines must be properly implemented in order to help reduce further Legionnaires’ disease outbreaks associated with evaporative cooling systems.^

Compendium of measures to prevent disease associated with animals in public settings, 2005 /

"March 25, 2005."

El Niño Southern Oscillation and Ross River Virus Outbreaks in Australia

Various authors have suggested a general predictive value of climatic indices of El Nino/Southem Oscillation events as indicators of outbreaks of arbovirus disease, particularly Ross River virus in Australia. By analyzing over 100 years of historical outbreak data on Ross River virus disease, our data indicate that, although high Southern Oscillation Index and La Nina conditions are potentially important predictors for the Murray Darling River region, this is not the case for the other four ecological zones in Australia. Our study, therefore, cautions against overgeneralization and suggests that, since climate and weather exert different influences and have different biological implications for the multiplicity of vectors involved, it is logical that predictors should be heterogeneous.

Dynamics of a temperature-related coral disease outbreak

During the austral summer of 2001/2002, a coral epizootic occurred almost simultaneously with a bleaching event on the fringing reefs of Magnetic Island (Great Barrier Reef region), Australia. This resulted in a 3- to 4-fold increase in the mean percentage of partial mortality rate in a population of the hard coral Montipora aequituberculata. The putative disease state, ‘atramentous necrosis’, was observed on both bleached and normally-pigmented M. aequituberculata, and presented blackened lesions that spread within days across the colony surface and throughout the population. Diseased portions of the corals were only visible for 3 to 4 wk, with diseased tissues becoming covered in sediment and algae, which rapidly obscured evidence of the outbreak. Diseased colonies were again observed in the summer of 2002/2003 after being absent over the 2002 winter. Analysis of when diseased and bleached corals were first observed, and when and where the mortality occurred on individual colonies, indicated virtually all the mortality over the summer could be attributed to the disease and not to the bleaching. Fluorescence in situ hybridisation (FISH) techniques and cloning, and analysis of the 16S rRNA genes from diseased coral tissue, identified a mixed microbial assemblage in the diseased tissues particularly within the Alphaproteobacteria, Firmicutes and Bacteroidetes. While it is not possible in this study to distinguish between a disease-causing microbial community versus secondary invaders, the bacterial 16S rDNA sequences identified within the blackened lesions demonstrated high similarity to sequences from black band disease and white plague infected corals, suggesting either common aetiological agents or development of a bacterial community that is specific to degrading coral tissues. Temperature-induced coral disease outbreaks, with the potential for elevated levels of mortality, may represent an added problem for corals during the warmer summer months and an added dimension to predicted increases in water temperature from climate change.

Differences in climatic factors between Ross River virus disease outbreak and nonoutbreak years

Ross River virus is a common mosquito-borne arbovirus responsible for outbreaks of polyarthritic disease throughout Australia. To better understand climatic factors preceding outbreaks, we compared seasonal and monthly rainfall and temperature trends in outbreak and nonoutbreak years at four epidemic-prone locations. Our analyses showed that rainfall in outbreak years tended to be above average and higher than rainfall in nonoutbreak years. Overall temperatures were warmer during outbreak years. However, there were a number of distinct deviations in temperature, which seem to play a role in either promoting or inhibiting outbreaks. These preliminary findings show that climatic differences occur between outbreak and nonoutbreak years; however, seasonal and monthly trends differed across geo-climatic regions of the country. More detailed research is imperative if we are to optimize the surveillance and control of epidemic polyarthritic disease in Australia.

Microbial community of black band disease on infection, healthy and dead part of scleractinian Montipora sp. colony at Seribu islands, Indonesia

It is crucial to understand the microbial community associated with the host when attempting to discern the pathogen responsible for disease outbreaks in scleractinian corals. This study determines changes in the bacterial community associated with Montipora sp. in response to black band disease in Indonesian waters. Healthy, diseased, and dead Montipora sp. (n = 3 for each sample type per location) were collected from three different locations (Pari Island, Pramuka Island, and Peteloran Island). DGGE (Denaturing Gradient Gel Electrophoresis) was carried out to identify the bacterial community associated with each sample type and histological analysis was conducted to identify pathogens associated with specific tissues. Various Desulfovibrio species were found as novelty to be associated with infection samples, including Desulfovibrio desulfuricans, Desulfovibrio magneticus, and Desulfovibrio gigas, Bacillus benzoevorans, Bacillus farraginis in genus which previously associated with pathogenicity in corals. Various bacterial species associated with uninfected corals were lost in diseased and dead samples. Unlike healthy samples, coral tissues such as the epidermis, endodermis, zooxanthellae were not present on dead samples under histological observation. Liberated zooxanthellae and cyanobacteria were found in black band diseased Montipora sp. samples.

Positive Selection Results in Frequent Reversible Amino Acid Replacements in the G Protein Gene of Human Respiratory Syncytial Virus

Human respiratory syncytial virus (HRSV) is the major cause of lower respiratory tract infections in children under 5 years of age and the elderly, causing annual disease outbreaks during the fall and winter. Multiple lineages of the HRSVA and HRSVB serotypes co-circulate within a single outbreak and display a strongly temporal pattern of genetic variation, with a replacement of dominant genotypes occurring during consecutive years. In the present study we utilized phylogenetic methods to detect and map sites subject to adaptive evolution in the G protein of HRSVA and HRSVB. A total of 29 and 23 amino acid sites were found to be putatively positively selected in HRSVA and HRSVB, respectively. Several of these sites defined genotypes and lineages within genotypes in both groups, and correlated well with epitopes previously described in group A. Remarkably, 18 of these positively selected tended to revert in time to a previous codon state, producing a ""flipflop'' phylogenetic pattern. Such frequent evolutionary reversals in HRSV are indicative of a combination of frequent positive selection, reflecting the changing immune status of the human population, and a limited repertoire of functionally viable amino acids at specific amino acid sites.

Report of the equine herpesvirus-1 Havermeyer Workshop, San Gimignano, Tuscany, June 2004

Amongst the infectious diseases that threaten equine health, herpesviral infections remain a world wide cause of serious morbidity and mortality. Equine herpesvirus-1 infection is the most important pathogen, causing an array of disorders including epidemic respiratory disease abortion, neonatal foal death, myeloencephalopathy and chorioretinopathy. Despite intense scientific investigation, extensive use of vaccination, and established codes of practice for control of disease outbreaks, infection and disease remain common. While equine herpesvirus-1 infection remains a daunting challenge for immunoprophylaxis, many critical advances in equine immunology have resulted in studies of this virus, particularly related to MHC-restricted cytotoxicity in the horse. A workshop was convened in San Gimignano, Tuscany, Italy in June 2004, to bring together clinical and basic researchers in the field of equine herpesvirus-1 study to discuss the latest advances and future prospects for improving our under-standing of these diseases, and equine immunity to herpesviral infection. This report highlights the new information that was the focus of this workshop, and is intended to summarize this material and identify the critical questions in the field. (c) 2006 Elsevier B.V. All rights reserved.

Determination of temperature variation during the individual steps of the production of hospital diets of modified consistency

Background & aim: Many disease outbreaks of food origin are caused by foods prepared in Food Service and Nutrition Units of hospitals, affecting hospitalized patients who, in most cases, are immunocompromised and therefore at a higher risk of severe worsening of their clinical status. The aim of this study was to determine the variations in temperature and the time-temperature factor of hospital diets. Methods: The time and temperature for the preparation of 4 diets of modified consistency were determined on 5 nonconsecutive days in a hospital Diet and Nutrition Unit at the end of preparation and during the maintenance period, portioning and distribution at 3 sites, i.e., the first, the middle and the last to receive the diets. Results and discussion: All foods reached an adequate temperature at the end of cooking, but temperature varied significantly from the maintenance period to the final distribution, characterizing critical periods for microorganism proliferation. During holding, temperatures that presented a risk were reached by 16.7% of the meats and 59% of the salads of the general diet, by 16.7% of the garnishes in the bland diet and by 20% of the meats and garnishes in the viscous diet. The same occurred at the end of distribution for 100% of the hot samples and of the salads and for 61% of the desserts. None of the preparations remained at risk temperature for a time exceeding that established by law. Conclusion: The exposure to inadequate temperature did not last long enough to pose risks to the patient.

Segurança alimentar nos refeitórios de uma universidade portuguesa : aplicação da teoria do comportamento planeado

A Organização Mundial de Saúde estima que nos países mais industrializados uma em cada três pessoas sofra, por ano, de uma doença de origem alimentar. De acordo com os dados da Agência Europeia para a Segurança Alimentar foram relatados pelos 27 Estados Membros da União Europeia, no ano 2012, um total de 5.363 surtos de origem alimentar, assistindo-se a uma prevalência do setor da restauração, como o local de maior ocorrência dos surtos de doenças de origem alimentar. Para o mesmo ano, Portugal reportou 7 surtos de origem alimentar, envolvendo 135 pessoas com 42 hospitalizações. Neste contexto, a aplicação de boas práticas de higiene, nomeadamente no setor da restauração, é essencial para proteger o consumidor das doenças de origem alimentar. Neste estudo, pretendeu-se identificar os constructos do modelo da Teoria do Comportamento Planeado (Theory of Planned Behaviour – TPB, segundo a terminologia anglo-saxónica), de Icek Ajzen, que melhor explicam a intenção dos operadores de alimentos em adotarem os comportamentos de higiene, a saber: i) utilização de luvas e touca de proteção de cabelos, e ii) remoção de adornos pessoais, durante a manipulação de alimentos. Para o efeito, foi aplicado um questionário tendo por base a Teoria do Comportamento Planeado, a uma amostra de cento e vinte e três operadores dos vários refeitórios de uma universidade portuguesa, na sua grande maioria do sexo feminino (91,1%) e que manipulam alimentos numa base diária, recorrendo-se primeiramente a uma fase preliminar de estudo qualitativo, ou pré-inquérito, para melhor selecionar os temas essenciais e as principais categorias a considerar na construção deste inquérito. Os inquéritos foram tratados estatisticamente recorrendo-se à estatística descritiva, à análise fatorial e avaliação da consistência interna dos fatores resultantes, seguido da aplicação de regressão linear e metodologia de análise de trajetórias (path modeling) com vista à validação do TPB. Os resultados obtidos apontam para o fato de a Atitude ser o melhor preditor da Intenção em adotar os comportamentos em estudo. Verificou-se também que a motivação de cumprir resulta da pressão exercida pelos superiores hierárquicos ou colegas, influenciando positivamente a intenção, na medida em que as crenças normativas assumiram-se como sendo o segundo preditor que melhor previu a intenção.

Aedes albopictus may not be vector of dengue virus in human epidemics in Brazil

Over 60,500 dengue cases were reported in the state of Espírito Santo (ES), Brazil, between 1995 and 1998. The study's purpose was to identify whether Aedes albopictus was transmitting the dengue virus during an epidemic in the locality of Vila Bethânia (Viana County),Vitória, ES. From April 3 to 9, 1998, blood and serum samples were collected daily for virus isolation and serological testing. Four autochthonous cases were confirmed through DEN 1 virus isolation and two autochthonous cases through MAC ELISA testing. Of 37 Ae. aegypti and 200 Ae. albopictus adult mosquitoes collected and inoculated, DEN1 virus was isolated only from a pool of two Ae. aegypti female mosquitoes. The study results suggest that Ae. albopictus still cannot be considered an inter-human vector in dengue epidemics in Brazil.

Dengue and the risk of urban yellow fever reintroduction in São Paulo State, Brazil

OBJECTIVE: To propose a mathematical method for the estimation of the Basic Reproduction Number, R0, of urban yellow fever in a dengue-infested area. METHODS: The method is based on the assumption that, as the same vector (Aedes aegypti) causes both infections, all the quantities related to the mosquito, estimated from the initial phase of dengue epidemic, could be applied to yellow fever dynamics. It is demonstrated that R0 for yellow fever is, on average, 43% lower than that for dengue. This difference is due to the longer dengue viremia and its shorter extrinsic incubation period. RESULTS: In this study the analysis was expanded to the epidemiological situation of dengue in São Paulo in the year 2001. The total number of dengue cases increased from 3,582 in 2000 to 51,348 in 2001. It was then calculated R0 for yellow fever for every city which have shown R0 of dengue greater than 1. It was also estimated the total number of unprotected people living in highly risky areas for urban yellow fever. CONCLUSIONS: Currently there is a great number of non-vaccinated people living in Aedes aegypti infested area in the state of São Paulo.