Bats, Bat-Borne Viruses, and Environmental Changes

During the past decade, bats were shown to a major source for new viruses. Among them are well known coronaviruses such as SRAS or MERS but also Ebola. At the same time, no direct infection from bat to human has been demonstrated. The dynamic of transmission of bat-borne viruses is therefore a complex process involving both sylvatic and urban cycles, and intermediate hosts not always identified. The threat potentially exists, and drivers must be sought for man-made environmental changes. Anthropized environments are mosaic landscapes attracting at the same place different bat species usually not found together. Anthropized landscape is also characterized by a higher density of bat-borne viruses. The threat of new bat-borne virus outbreaks has greatly increased in the recent years along with media anthropization and the extremely rapid deforestation process. Deforestation could be a major contributing factor to new viral emergences due to more frequent contacts of livestock and humans with bats possibly containing infectious viruses

Insect cell endocytosis of chikungunya virus adapted to Aedes albopictus, a mosquito recently introduced into southern France

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Apoptosis of uninfected cells induced by HIV envelope glycoproteins

Apoptosis, or programmed cell death, is a key event in biologic homeostasis but is also involved in the pathogenesis of many human diseases including human immunodeficiency virus (HIV) infection. Although multiple mechanisms contribute to the gradual T cell decline that occurs in HIV-infected patients, programmed cell death of uninfected bystander T lymphocytes, including CD4+ and CD8+ T cells, is an important event leading to immunodeficiency. The HIV envelope glycoproteins (Env) play a crucial role in transducing this apoptotic signal after binding to its receptors, the CD4 molecule and a coreceptor, essentially CCR5 and CXCR4. Depending on Env presentation, the receptor involved and the complexity of target cell contact, apoptosis induction is related to death receptor and/or mitochondria-dependent pathways. This review summarizes current knowledge of Env-mediated cell death leading to T cell depletion and clinical complications and covers the sometimes conflicting studies that address the possible mechanisms of T cell death

Functional significance of genotoxicity in fish germ cells

The aquatic environment is becoming increasingly contaminated by pollutants having a genotoxic potential towards organisms and in particular in fish. Such genotoxins are prone to affect directly offspring or indirectly through the reproductive process. All this could influence recruitment rate and hence the population dynamics. However, assessment of the ecological risks associated with environmental genotoxic exposure is usually based on individual responses. Thus, there is a need for a better understanding of the long term and population level implications of genotoxic insults in fish. While low levels of DNA damage in somatic cells and oocytes can be efficiently repaired, mature sperm cells, i.e. spermatozoa, are susceptible to accumulate damage due to their lack of repair capacity. The present work aims to track the transfer of toxic effects across generations by studying the link between the level of DNA damage in fish sperm, and the rate of development abnormalities measured in the offspring after parental exposure to the model genotoxicant MMS. Three different fish species were chosen based either on their ecological importance or on their reproduction behavior, respectively brown trout (Salmo trutta), Arctic charr (Salvelinus alpinus) and threespine stickleback (Gasterosteus aculeatus). Results show a significant increase in sperm DNA damage measured with the comet assay in exposed organisms. This damage did not impact on fertilization success but led further to a significant increase in embryo abnormality rate at early embryonic and late larval stages, and further delayed growth in exposed group compared to the control

Emergence of Bat-Related Betacoronaviruses: Hazard and Risks

The current Coronavirus Disease 2019 (COVID-19) pandemic, with more than 111 million reported cases and 2,500,000 deaths worldwide (mortality rate currently estimated at 2.2%), is a stark reminder that coronaviruses (CoV)-induced diseases remain a major threat to humanity. COVID-19 is only the latest case of betacoronavirus (β-CoV) epidemics/pandemics. In the last 20 years, two deadly CoV epidemics, Severe Acute Respiratory Syndrome (SARS; fatality rate 9.6%) and Middle East Respiratory Syndrome (MERS; fatality rate 34.7%), plus the emergence of HCoV-HKU1 which causes the winter common cold (fatality rate 0.5%), were already a source of public health concern. Betacoronaviruses can also be a threat for livestock, as evidenced by the Swine Acute Diarrhea Syndrome (SADS) epizootic in pigs. These repeated outbreaks of β-CoV-induced diseases raise the question of the dynamic of propagation of this group of viruses in wildlife and human ecosystems. SARS-CoV, SARS-CoV-2, and HCoV-HKU1 emerged in Asia, strongly suggesting the existence of a regional hot spot for emergence. However, there might be other regional hot spots, as seen with MERS-CoV, which emerged in the Arabian Peninsula. β-CoVs responsible for human respiratory infections are closely related to bat-borne viruses. Bats are present worldwide and their level of infection with CoVs is very high on all continents. However, there is as yet no evidence of direct bat-to-human coronavirus infection. Transmission of β-CoV to humans is considered to occur accidentally through contact with susceptible intermediate animal species. This zoonotic emergence is a complex process involving not only bats, wildlife and natural ecosystems, but also many anthropogenic and societal aspects. Here, we try to understand why only few hot spots of β-CoV emergence have been identified despite worldwide bats and bat-borne β-CoV distribution. In this work, we analyze and compare the natural and anthropogenic environments associated with the emergence of β-CoV and outline conserved features likely to create favorable conditions for a new epidemic. We suggest monitoring South and East Africa as well as South America as these regions bring together many of the conditions that could make them future hot spots

Investigating the host specificity of Campylobacter jejuni and Campylobacter coli by sequencing gyrase subunit A

Abstract This research evaluated the association between socio demographic characteristics and housing satisfaction of Iranian immigrant’s homeowners in Kuala Lumpur, Malaysia. Data was collected from 325 participants through self-administered questionnaire.  Pearson’s correlation analysis revealed  monthly income of first income earner, total earned income earner, price of residential unit, number of bed room, time owners have been in Malaysia,  had positive significant relationship with housing satisfaction of Iranian immigrants homeowners  in  the study region. Nevertheless, there was no significant association between age, number of bath room, number of dining room, number of living room, length of residence in current house, monthly income of second income earner, number of income earner, number of children, and size of household and housing satisfaction of the immigrant owners’ households. Analysis of variance (ANOVA) indicated that housing satisfaction differed between level of education, level of income, and level of price of residential unit. Independent t-test shown that there was significant difference between gender and housing satisfaction of the participants. These associations indicate that those who are females, higher income, higher education, higher residential unit with more room are more satisfied. It is recommended planners and policy makers should prominence on development of housing conditions of immigrant’s households to increase their housing satisfaction. Keywords:background characteristic, housing satisfaction, housing, immigrant’s homeowner’s household

VSV-G pseudotyping rescues HIV-1 CA mutations that impair core assembly or stability

<p>Abstract</p> <p>Background</p> <p>The machinery of early HIV-1 replication still remains to be elucidated. Recently the viral core was reported to persist in the infected cell cytoplasm as an assembled particle, giving rise to the reverse transcription complex responsible for the synthesis of proviral DNA and its transport to the nucleus. Numerous studies have demonstrated that reverse transcription of the HIV-1 genome into proviral DNA is tightly dependent upon proper assembly of the capsid (CA) protein into mature cores that display appropriate stability. The functional impact of structural properties of the core in early replicative steps has yet to be determined.</p> <p>Results</p> <p>Here, we show that infectivity of HIV-1 mutants bearing S₁₄₉A and S₁₇₈A mutations in CA can be efficiently restored when pseudotyped with vesicular stomatitis virus envelope glycoprotein, that addresses the mutant cores through the endocytic pathway rather than by fusion at the plasma membrane. The mechanisms by which these mutations disrupt virus infectivity were investigated. S₁₄₉A and S₁₇₈A mutants were unable to complete reverse transcription and/or produce 2-LTR DNA. Morphological analysis of viral particles and <it>in vitro </it>uncoating assays of isolated cores demonstrated that infectivity defects resulted from disruption of the viral core assembly and stability for S₁₄₉A and S₁₇₈A mutants, respectively. Consistent with these results, both mutants failed to saturate TRIM-antiviral restriction activity.</p> <p>Conclusion</p> <p>Defects generated at the level of core assembly and stability by S₁₄₉A and S₁₇₈A mutations are sensitive to the way of delivery of viral nucleoprotein complexes into the target cell. Addressing CA mutants through the endocytic pathway may compensate for defects generated at the reverse transcription/nuclear import level subsequent to impairment of core assembly or stability.</p

Incidence of dengue and chikungunya viruses in mosquitoes and human patients in border provinces of Vietnam

Background: Dengue virus remains a major threat in Vietnam, while chikungunya virus is expected to become one. Surveillance was conducted from 2012 to 2014 in Vietnam to assess the presence of dengue and chikungunya viruses in patients hospitalized with acute fever in five Vietnam provinces neighboring Lao PDR and Cambodia. Surveillance was extended to mosquitoes present in the vicinity of the patients' households. Results: A total 558 human serum samples were collected along with 1104 adult mosquitoes and 12,041 larvae from 2250 households. Dengue virus was found in 17 (3%) human serum samples and in 9 (0.8%) adult mosquitoes. Chikungunya virus was detected in 2 adult mosquitoes (0.18%) while no chikungunya virus was detected in humans. Differing densities of mosquito populations were found, with the highest in the Long An Province border with Cambodia. Long An Province also displayed the lowest rate of infection, despite a very high Breteau Index, high human population density and presence of the main cross border road system. The highest incidence was found in Dac Nong Province, where the Breteau and Container indices were the second lowest. Dengue virus was detected in five Aedes albopictus, three Aedes aegypti and one Culex vishnui. Chikungunya virus was detected in two Ae. aegypti. All infected mosquitoes belonged to haplotypes described in other parts of the world and a number of novel haplotypes were found among uninfected mosquitoes. Conclusions: Dengue is considered to be regularly introduced to Vietnam from Cambodia, mostly through human movement. The data reported here provides a complementary picture. Due to intensive international trade, long-distance transportation of mosquito populations may play a role in the regular importation of dengue in Vietnam through Ho Chi Minh City. It is important to decipher the movement of mosquitoes in Vietnam, not only at the Lao PDR and Cambodia borders but also through international trade routes. Mosquito surveillance programs should address and follow mosquito populations instead of mosquito species