Way Of Contamination Research Articles

The problems of counteraction to HIV-infection and its prevention in places of imprisonment

The article considers the problem of organizing prevention and treatment of HIV-infection in suspected, accused and convicted persons in places of deprivation of liberty. The HIV-infected individuals in places of deprivation of liberty are in situation of increased risk that creates objective necessity for in-depth study of this phenomenon. The purpose of the study was to determine specific characteristics of organization of support of HIV-infected individuals, to identify ways of contamination and its main risk factors among both suspected, accused and convicted persons and penitentiary institution personnel. The study provided sorting out of main aspects that resulting in convicts' refusal to receive drugs and treatment. The corresponding recommendations for optimizing general and particular prevention of these negative phenomena were developed. The conclusion was made that it is possible to apply complex methods to motivate convicted HIV patients for treatment. Some of these methods can include such medical social psychological measures of organizational managerial character as training of specialists; participation of HIV patients in comprehensive preventive programs; group support of convicted HIV patients; positive reinforcement application; individual approach.

Ensuring food safety using digital technologies

The article discusses the conditions and periods of storage of cereals and flour. Processes occurring in the objects under study when storage conditions are not met, ways of contamination of grain stocks by pests. The use of digital methods will ensure transparency of all links - from producer to consumer, and feedback will help to find and localize the source of infection.

Schistosomiasis Control in Burkina Faso: Knowledge, Attitudes, and Practices of Populations in Four Villages

Schistosomiasis is Africa’s second most common parasitosis in terms of morbidity and mortality. Humans have been identified as being primarily responsible for the persistence and dissemination of the disease within their environment. The aim of this study was to assess the theoretical and behavioral knowledge of an at-risk population in the control of schistosomiasis. 
 
 This was a descriptive cross-sectional study conducted from September 2021 to January 2022 in four villages in Burkina Faso: Pana, Vy, Bourzem, and Zam. The study population consisted of individuals aged 7-59 years, who were recruited from randomly selected households; any eligible person in each household who consented to participate was surveyed. A questionnaire was used to collect information on knowledge about schistosomiasis, attitudes, and practices at the individual level, as well as control behavior.
 
 A total of 527 participants were surveyed in the villages. The mean age was 26.76 (+/-14.22) years. The sex ratio was 0.84. More than half of the participants (59.27%) had never attended school. The symptoms of schistosomiasis were unknown to 42.13% of the participants. Bathing in contaminated water was known as a way of contamination by 29.22% of participants. Among the participants, 40.55% were aware of mass treatment campaigns, however, 43.19% of them found them ineffective. More than half (51.16%) of those using the village water point did not know that they were at risk of contracting the disease. Of the 20.89% of participants with a history of schistosomiasis, 22.22% used traditional medicines.
 
 The inadequate knowledge of the study population shows their vulnerability to the disease. The approximate attitude and practices highlight the socio-cultural specificities that influence the adoption of good practices in the control of the disease.

ФАКТОРЫ ВНЕШНЕЙ СРЕДЫ И ИХ ВЛИЯНИЕ НА ПУТИ КОНТАМИНАЦИИ МЯСА МИКРООРГАНИЗМАМИ

Sources of microorganism contamination of meat are extremely diverse. There are two known ways of contamination of organs and tissues of animals with microorganisms: endogenous and exogenous. With endogenous seeding, meat can contain both saprophytic microorganisms that do not cause disease in animals, and pathogenic if the animal was sick. These microorganisms in the future will either lead to accelerated spoilage of meat, or can become a source of disease for humans. Exogenous seeding of meat occurs when microorganisms enter the meat from the external environment, during slaughter, gutting and skinning, subsequent cutting of the carcass and storage. A variety of microorganisms can be found on the surface of the animal’s skin. Also, one of the factors contributing to the seeding of meat is sloppy gutting of carcasses, damage to the intestines. It is necessary to follow certain rules and cleanliness when slaughtering animals and cutting, so that all objects that come into contact with the carcass are clean. The article considers and evaluates some environmental factors and their influence on the ways of contamination of meat by microorganisms.

Involvement of Healthcare Staff from First Contact Health Establishments in the Elimination of Human Rabies in the Health Districts of Ferkessedougou and Kong in Ivory Coast, 2020

Introduction: Rabies is endemic and constitutes a public health problem in Côte d’Ivoire. In the health districts of Kong and Ferkessedougou, exposure to rabies infection reported by the National Institute of Public Hygiene of Ferkessedougou averages 200 cases per year. However, in the involvement of health workers from First Contact Health Establishments (FCHE) of the 2 Districts, the management of exposed persons is unknown. This study aimed to determine the involvement of healthcare personnel in FCHE in the health districts of Ferkessedougou and Kong in the elimination of human rabies. Material and Methods: This was a prospective cross-sectional study with a descriptive aim which took place from October 21, 2020 to November 20, 2020. The data were collected using a questionnaire and then analyzed with the software EXCEL and Epi Info 3.5.3. Principle Results: It emerged from this study that the average age of the participants was 36.8 years with an average professional seniority of 5.07 years. The majority (73.90%) of healthcare staff have not received training on rabies. However, plenty of healthcare personnel respectively experienced the transmission of the rabies virus from animals to humans (98.60%), with dogs (97.10%) as the main animal vector of rabies to man, the bite (100%) as the way of contamination of rabies, the immediate washing with water and soap (66.70%), the administration of the anti-rabies vaccine (75.4%), the National Institute of Public Hygiene as a reference structure (63.8%). At the level of practices after exposure to rabies infection, the majority (65.2%) of the healthcare staff consulted the patients, of whom 84.4% and 95.6% of these consultants respectively carried out communication for social change and behavior and referred patients to the National Institute of Public Hygiene (p < 0.01). Conclusion: Some health workers did not have the necessary knowledge to care for people exposed to rabies infection. Thus, they were not all involved in post-exposure prophylaxis against rabies. It would therefore be desirable for the National Institute of Public Hygiene to strengthen the capacities for the prevention of rabies for all human health workers, particularly those in first contact health establishments with a view to eliminating this disease from here in 2030.

Study on Microbiological Quality of Vender Chicken Livers in Jalalabad City

Liver is chemically complex matrixes contain sufficient nutrients that support microbial growth. Microbial contamination of vending chicken livers could occur due to different possible reasons such as storing foods in cheap utensils, holding foods at a temperature that would permit bacterial growth, utilization of water of questionable hygienic quality, using packing materials that were not of food-grade quality, vending site that has no facilities for waste disposal and utilization of unclean utensils. In addition, street chicken livers vendors are unaware of the basic importance of personal cleanliness, thus their products are usually vulnerable to gross contamination by flies, insects, rodents, dust and other dirt. Vending chicken livers are often poor and uneducated and lack appreciation for safe food handling. Aim of the study is to determine microbiological quality of chicken livers in Jalalabad city. A total of 24 samples of vender chicken livers from 4 different shops had purchased from Jalalabad city Afghanistan. This step occurred earlier than the chilling period then Transfer Directly to the Microbiological laboratory of Veterinary Science faculty of Nangarhar University for Microbial culture and microscopic examination. According to our study we have seen 6 (25%) samples positive for Salmonella and 24(100%) samples positive for Shigella. Studies made in Nangarhar pointed out that the important aspect of vending chicken livers is their safety and understanding the possible ways of contamination. The sanitary condition need to be improved. The government must develop microbiological standards of fast food and urgently put them in practice.

SÜTÜN MİKROBİYOTASI VE BOZULMASINA YOL AÇAN ÖNEMLİ BAKTERİLER

Süt sağımdan başlayarak işleninceye kadar çeşitli ortamlardan, ekipmanlardan ve personelden bulaşan mikroorganizmalar nedeniyle bozulur. Süt mikrobiyotasında laktik asit bakterileri, psikrotrofik Gram negatif bakteriler, Gram pozitif sporlu bakteriler ve patojen bakteriler bulunur. Bu bakteri ve enzimlerin faaliyeti sütün duyusal ve yapısal özelliklerini değiştirerek bozulmasına neden olur. Çiğ süt mikrobiyotası hem sütün hem de süt ürünlerinin kalite ve güvenliğini etkileyen en önemli parametrelerden birisi olup, bir taraftan çiftlik ortamını yansıtırken, diğer taraftan sağım ve işletme koşulları hakkında da fikir verir. Çiğ sütte sıklıkla bulunan ve sütün bozulmasına yol açan en önemli bakteriler Pseudomonas, Acinetobacter, Brevundimonas, Flavobacterium ve bazı koliform üyeleridir. Sütün bozulmasında pastörizasyon öncesi bulaşmaların yanında pastörizasyon sonrası bulaşmalara bağlı mikroorganizma faaliyeti de önemli rol oynar. Özellikle psikrotrofik termofilik karakterdeki Bacillus türleri pastörizasyondan sonra meydana gelen bozulmalardan sorumludur. Bu makalede, sütün mikroorganizmalarla bulaşma yolları, sütte bulunan mikroorganizmaların özellikleri ve sütün bozulmasındaki rolleri konusunda bilgiler sunulmuştur.

Evaluation of Healthcare Professionals in Contact with Patients Diagnosed with COVID-19 Detected Outside of the Pandemic Service in our Hospital

The "Coronavirus Disease 19 (COVID-19)" caused by "Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)" is still active all over the world as a pandemia. It is reported that at least 7000 health care workers (HCW) had lost their lives due to COVID-19 from the beginning of the pandemia till September 2020 in the world. In our country between the dates, March 11, 2020 which the first case was reported, and September 1, 2020, the date which our study has been finalized, 7428 HCW were infected by SARS-CoV-2, and 52 of them were deceased. In this study, it was aimed to evaluate the contact and illness of healthcare workers working outside of the pandemic clinics in our hospital and to examine the possible transmission routes and disease prognoses. Healthcare workers who were working outside the pandemic service between March 11, 2020 and September 1, 2020 and who had a definite diagnosis of COVID-19 and all hospital staff who had contacted with these people, and HCW who had contact with patients diagnosed with COVID-19 while receiving inpatient treatment in services other than the pandemic service was evaluated and classified as low, medium and high risk according to the risk scoring defined in the published "Ministry of Health COVID-19 Guidelines". Healthcare workers who were evaluated as contacted were questioned in detail regarding the use of personal protective equipment (PPE) at the time of contact, especially suitability of the masks, contact time and shape and all the data were recorded. A total of 53 index cases (40 HCW and 13 inpatients diagnosed as COVID-19) were detected during the study period. The number of HCW contacted with these index cases was 672. In our study, we examined the data of 40 index cases and 672 contacted HCW (total of 712 HCW). Only 3 of 40 index cases (7.5%) had hospital-acquired COVID-19 infection, the other 37 cases were infected by community sources. COVID-19 was not detected in 94.2% of the contacted HCW during the follow-up while 5.8% of them had positive PCR test results. Considering the possible way of contamination among the contacted HCW who developed COVID-19 during the follow-up period, it was determined that 13.1% of the cases were a result of taken care of patients, 86.9% of the cases were a result of being in hospital social environments (drinking tea, smoking, eating, chatting in the same room without personal precautions) and in the days after the contact, it was in the form of contact with healthcare personnel diagnosed with COVID-19. When the contacted HCW were questioned about using proper masks at the time of contact, we determined that 93.3% of them used masks during patient caring procedures, however, only 48.9% used masks when they were in social areas (p<0.001). Healthcare workers face an unprecedented risk of occupational disease and death due to the COVID-19 pandemic. However, it is also observed that prolonged pandemia period caused health workers to disregard rigorous infection control precautions in social areas of hospitals which they follow inpatient care although this has shown to be the most common way of contamination. Commonly performed in-service training and causing awareness in all areas of the hospital about following infection control precautions and PPE usage and checking the process regularly are the most important ways to prevent HCW from being affected by COVID-19.

Glyphosate effects on tree species natives from Cerrado and Caatinga Brazilian biome: Assessing sensitivity to two ways of contamination

Glyphosate is applied for dissection in no-till and post-emergence management in transgenic crops in agricultural fields near the Cerrado and Caatinga biomes. These biomes together represent 33.8% of the Brazilian territory, contributing to the maintenance of great world diversity in flora and fauna. Despite actions to protect them, the proximity with agricultural areas and intense use of glyphosate puts at risk the preservation of native vegetation due to the contamination via herbicide transport processes. Our objectives were: i) to determine the sensitivity of native species from the Cerrado and Caatinga to glyphosate contamination via drift and groundwater; ii) evaluate the level of sensitivity to glyphosate among the different organs of plants. The highest intoxications (upper 80%) were observed for Bauhinia cheilantha, Mimosa caesalpiniaefolia, Mimosa tenuiflora and Amburana cearensis due to drift simullation. The species with 90% of total dry matter reduction were Bauhinia cheilantha, Enterolobium contortisiliquum, Mimosa caesalpiniaefolia, Mimosa tenuiflora, Tabebuia aurea. B. cheilantha and M. tenuiflora are most affected by exposure to glyphosate drift, with 50% of total dry matter reduction when exposed to doses below 444,0 g ha−1. Leaf growth is more sensitive to glyphosate for drift exposure for most species. Hymenaea courbaril is an exception, with greater sensitivity to root growth (50% dry matter reduction at doses below 666,0 g ha−1). B. cheilantha is the species most sensitive to drift exposure; however, it showed complete tolerance to contamination in subsurface waters. Other species such as Anadenanthera macrocarpa and M. caesalpiniifolia are also sensitive to drift, but without reach 90% of total dry matter reduction. A. macrocarpa, M. caesalpiniifolia and T. aurea were tolerant to contamination by subsurface water. The differential tolerance of trees confirms glyphosate's potential as a species selection agent in the Cerrado and Caatinga biomes.

Phthalates in beverages - A review

Phthalates as esters of phthalic acid and aliphatic alcohol are environmental contaminants which are commonly observed due to their widespread use as plasticizers. Their chemical and physical properties allow them to migrate into the environment and also into foods and beverages easily. The objective of this paper is a summarized overview of phthalate properties, their impact on human health, their content in beverages, especially in beer, including the ways of contamination, and last but not least also legislative regulations.

Safety of ready-to-eat chicken in Burkina Faso: Microbiological quality, antibiotic resistance, and virulence genes in Escherichia coli isolated from chicken samples of Ouagadougou.

In Burkina Faso, flamed/grilled chickens are very popular and well known to consumers. The aim of this study was to evaluate the microbiological quality, the antibiotic resistance, and the virulence gene from Escherichia coli isolated from these chickens in Ouagadougou. A total of 102 grilled, flamed, and fumed chickens were collected in Ouagadougou and analyzed, using standard microbiological methods. All E. coli isolates were checked with the antimicrobial test and also typed by 16‐plex PCR. The mean of aerobic mesophilic bacteria (AMB) and thermo‐tolerant coliforms (TTC) was found respectively between 6.90 ± 0.12 × 107 CFU/g to 2.76 ± 0.44 × 108 CFU/g and 2.4 ± 0.82 × 107 CFU/g to 1.27 ± 0.9 × 108 CFU/g. E. coli strains were found to 27.45%. Forty samples (38.24%) were unacceptable based on the AMB load. Fifty‐nine samples (57.85%) were contaminated with TTCs. Low resistance was observed with antibiotics of betalactamin family. Diarrheagenic E. coli strains were detected in 21.43% of all samples. This study showed that flamed/grilled chickens sold in Ouagadougou could pose health risks for the consumers. Need of hygienic practices or system and good manufacturing practices is necessary to improve the hygienic quality of flamed/grilled chickens. Our results highlight the need of control of good hygiene and production practices to contribute to the improvement of the safety of the products and also to avoid antibiotic resistance. Slaughter, scalding, evisceration, plucking, bleeding, washing, rinsing, preserving, grilling, and selling may be the ways of contamination.

Coxsackievirus B4 vertical transmission in a murine model

BackgroundLife-threatening infections with type B Coxsackieviruses (CV-B) are frequently encountered among newborns and are partly attributed to vertically-transmitted virus. Our current study investigates this alternative way of contamination by CV-B, using a mouse model.MethodsPregnant Swiss mice were intraperitoneally inoculated with CV-B4 E2 at gestational day 10(G) or 17G. Dams and offspring were monitored for mortality and morbidity, and sampled at different time-points to document the infection and explore eventual vertical transmission.ResultsInoculation at day 10G induced an important rate of abortion and a decrease in the number of delivered pups per litter, whereas inoculation at day 17G was marked by preterm delivery and significant behavioral changes in dams. Only one case of spastic paralysis and one case of pancreatitis were recorded among surviving pups. Seroneutralization revealed anti-CV-B4 neutralizing antibodies in infected dams and their partial transfer to offspring. Viral genome detection by RT-PCR and viral progeny titration in several tissues (dams’ uteri, amniotic sac, amniotic fluid, placenta, umbilical cord, pancreas and heart) attested and documented CV-B4 vertical transmission to the majority of analyzed offspring. Virus detection in fetuses suggests transplacental transmission, but perinatal transmission during delivery could be also suggested. Vertically transmitted CV-B might even persist since prolonged viral RNA detection was noticed in the pancreas and heart from offspring born to dams inoculated at day 17G.ConclusionThis model of CV-B4 vertical transmission in mice, in addition to allow a better understanding of CV-B infections in fetuses and newborns, constitutes a useful tool to investigate the pathogenesis of CV-B associated chronic diseases.

Assessment of the biological and chemical availability of the freshly spiked and aged DDE in soil

The study compared the ability of various chemical methods (XAD, β-hydroxypropylcyclodextrin - HPCD) and solid phase micro-extraction (SPME)) to mimic earthworm uptake from two similar soils containing either spiked or aged p,p´-DDE, thus representing two extreme scenarios with regard to the length of pollutant-soil contact time and the way of contamination. The extent of bioaccumulation was assessed at fixed exposure periods (10 and 21 days) and at equilibrium derived from uptake curves by multiple-point comparison or kinetic modeling. The decision on the best chemical predictor of biological uptake differed. The degree of bioaccumulation at equilibrium was best predicted by XAD while HPCD rather reflected the extent of accumulation derived after 21 days when, however, steady-state was not reached for spiked p,p´-DDE. SPME seemed to underestimate the uptake of aged p,p´-DDE, probably of the fraction taken up via soil particles. Thus, the degree of predictability seems to be associated with the capability of the chemical method to mimic the complex earthworm uptake via skin and intestinal tract as well as with the quality of biological data where the insufficient length of exposure period appears to be the major concern.

Aerobic metabolism and cardiac activity in the descendants of zebrafish exposed to pyrolytic polycyclic aromatic hydrocarbons.

The increase of anthropogenic activities on coastal areas induces discharges of polycyclic aromatic hydrocarbons (PAHs) in aquatic ecosystem. PAH effects depend not only on their concentration and the way of contamination but also on the different developmental stages of the organism. Zebrafish were exposed to relevant concentration of pyrolytic PAHs from the first meal (i.e., 5-day post fertilization, dpf) to mature adults. Parental effect of this type of exposure was evaluated through the assessment of aerobic metabolic scope, cardiac frequency, and cardiac mRNA expression on larval and/or embryo progeny of contaminated fish. Our results suggest that cardiac frequency increased in larval descendants of fish exposed to the environmental concentration of pyrolytic PAHs (i.e., 5 ng.g(-1) of food), while a lack of effect on aerobic metabolism in 5 dpf larvae was highlighted. A surexpression of mRNA related to the cardiac calcium transporting ATPase atp2a2a, a protein essential for contraction, is in accordance with this increasing cardiac frequency. Even if cardiac development genes cmlc1 and tnnt2a were not affected at early life stages tested, complementary work on cardiac structure could be interesting to better understand PAHs action.

Commentary on "Post-Vietnam military herbicide exposures in UC-123 Agent Orange spray aircraft"

Phthalates are synthetic contaminants released into the environment notably by plastic waste. Semi-volatile, they adsorb to atmospheric particles and get distributed in all ecosystems. Effects of this major anthropogenic pollution in economical species in aquatic habitats have attracted large interest. On the contrary, very few studies have focused on wild terrestrial species. Yet, these lipophilic molecules are easily trapped by insect cuticle; ants and other insects have been shown to permanently bear among their cuticular components a non-negligible proportion of phthalates, meaning that they suffer from chronic exposure to these pollutants. Oral route could also be an additional way of contamination, as phthalates tend to stick to any organic particle. We show here via a food choice experiment that Lasius niger workers can detect, and avoid feeding on, food contaminated with DEHP (DiEthyl Hexyl Phthalate), the most widespread phthalate found in nature. This suggests that the main source of contamination for ants is atmosphere and that doses measured on the cuticle correspond to the chronic exposure levels for these animals. Such an ecologically relevant dose of DEHP was used to contaminate ants in lab and to investigate their physiological impact. Over a chronic exposure (1 dose per week for 5 weeks), the egg-laying rate of queens was significantly reduced lending credence to endocrine disruptive properties of such a pollutant, as also described for aquatic invertebrates. On the contrary, short term exposure (24 h) to a single dose of DEHP does not induce oxidative stress in ant workers as expected, but leads to activation of the immune system. Because of their very large distribution, their presence in virtually all terrestrial ecosystems and their representation at all trophic levels, ants could be useful indicators of contamination by phthalates, especially via monitoring the level of activation of their immune state.

Impact of ecological doses of the most widespread phthalate on a terrestrial species, the ant Lasius niger

Phthalates are synthetic contaminants released into the environment notably by plastic waste. Semi-volatile, they adsorb to atmospheric particles and get distributed in all ecosystems. Effects of this major anthropogenic pollution in economical species in aquatic habitats have attracted large interest. On the contrary, very few studies have focused on wild terrestrial species. Yet, these lipophilic molecules are easily trapped by insect cuticle; ants and other insects have been shown to permanently bear among their cuticular components a non-negligible proportion of phthalates, meaning that they suffer from chronic exposure to these pollutants. Oral route could also be an additional way of contamination, as phthalates tend to stick to any organic particle. We show here via a food choice experiment that Lasius niger workers can detect, and avoid feeding on, food contaminated with DEHP (DiEthyl Hexyl Phthalate), the most widespread phthalate found in nature. This suggests that the main source of contamination for ants is atmosphere and that doses measured on the cuticle correspond to the chronic exposure levels for these animals. Such an ecologically relevant dose of DEHP was used to contaminate ants in lab and to investigate their physiological impact. Over a chronic exposure (1 dose per week for 5 weeks), the egg-laying rate of queens was significantly reduced lending credence to endocrine disruptive properties of such a pollutant, as also described for aquatic invertebrates. On the contrary, short term exposure (24h) to a single dose of DEHP does not induce oxidative stress in ant workers as expected, but leads to activation of the immune system. Because of their very large distribution, their presence in virtually all terrestrial ecosystems and their representation at all trophic levels, ants could be useful indicators of contamination by phthalates, especially via monitoring the level of activation of their immune state.

Conhecimento dos dentistas sobre contaminação das hepatites B e C na rotina odontológica

The dental practices expose the trader to contamination risks of infectious diseases. In order to assess the degree of knowledge of dentists about the risk factors and methods of preventing infection by hepatitis B and C, was applied a questionnaire consisting of open and closed questions to one hundred randomly selected professionals in the municipality of Rio de Janeiro. Although 86% of participants considered themselves according to the official regulations of the Ministry of Health, there is still much to be modified in the routine of professionals. Though much of the dental surgeons have an injury perforating-cutting, their knowledge about the risks and ways of contamination is not satisfactory.

Patología implanto-endodóncica: concepto, tipos, diagnóstico, tratamiento y prevención

The implant-endodontic pathology is described in the literature as a cause of apical periimplantitis, understood to be an osteolytic lesion that appears in the apical region of the implant during the coronal osteointegration normally. This implant-endodontic pathology researches the relation of endodontic and implants apical lesions leading to infection contiguity between teeth and implants. The first way of contamination is implant-tooth, when the implant placement causes necrosis of the adjacent tooth and subsequent contamination of the implant; the second way is tooth-implant, when there is an exacerbation of latent apical lesion in a tooth, root canal or not, after placing an implant adjacent to it, resulting in apical periimplantitis later. In this work we have summoned the cases of occurring periimplantitis by apical residual infection present in the socket of an extracted tooth with apical periodontal pathology and replaced by an implant. This review aims to make an update of the relationship between periimplantitis and endodontics.

Eventual Role of Asymptomatic Cases of Dengue for the Introduction and Spread of Dengue Viruses in Non-Endemic Regions

In dengue virus infections the asymptomatic cases are much more frequent than the symptomatic ones, but their true role in the introduction and subsequent spread of dengue viruses in non-endemic regions remains to de clarified. We analyzed data from English and French literatures to assess if viremia in asymptomatic dengue infections might be sufficient to represent a true risk. During outbreaks of dengue a large number of individuals are infected and since viremia levels in symptomatic patients are known to vary by many orders of magnitude, it is reasonable to augur that a proportion of asymptomatic cases might reach levels of viremia sufficient to infect competent mosquitoes. In addition, a number of new ways of contamination in man by dengue viruses were recently described such as blood transfusion, bone marrow transplantation, and nosocomial infections that may be worth considering.

Infections inapparentes chez l’Homme : un cheval de Troie pour l’introduction et la diffusion des arbovirus transmis par des moustiques dans les régions non endémiques ?

In mosquito-borne arbovirus infections in man the asymptomatic cases are much more frequent than the symptomatic ones, but their true role in the introduction and subsequent spread of such diseases in non-endemic areas remains to be clarified. We have collected pertinent data from English and French literature from 1952 to 2010 through Pubmed and other bibliographic sources. Data were analysed to assess if viremia in asymptomatic human arbovirus infections might be sufficient to represent a true risk for introduction in non-endemic areas. During dengue and chikungunya fever outbreaks, humans are believed to be the only vertebrate hosts. Since a very large number of individuals are infected and since viremic levels are known to vary by many orders of magnitude in symptomatic patients, it is reasonable to augur that a proportion of asymptomatic cases might reach levels of viremia sufficient to infect competent mosquitoes. Moreover, in both dengue and chikungunya fever, nosocomial infections have been identified representing an alternative opportunity for virus introduction in non-endemic areas. In zoonotic mosquito-borne arbovirus infections such as Japanese encephalitis or West Nile infection, the situation is quite different since humans are considered as "dead-end" hosts. However, the very large number of asymptomatic cases arising during outbreaks and the existence of newly recognised ways of contamination (blood transfusion, organ transplantation, transplacental way etc.) may also ensure their introduction and subsequent spread in new areas.