Airborne Dust / Zoonosis / Land Use

This forum is to discuss general things concerning TSOI.
trader32176
Posts: 2723
Joined: Fri Jun 26, 2020 5:22 am

Re: Airborne Dust / Zoonosis / Land Use

Post by trader32176 »

Domestic dogs unlikely to transmit SARS-CoV-2, say researchers

2/19/21


https://www.news-medical.net/news/20210 ... chers.aspx


Researchers in Spain and Germany have conducted a study showing that domestic dogs are unlikely to contribute to the transmission and community spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) – the agent that causes coronavirus disease 2019 (COVID-19).

Infection with SARS-CoV-2 has recently been reported among various different species, including domestic cats and dogs. In addition, veterinarians in Spain detected an increase in severe lung pathologies in domestic dogs during the spring months of the year 2020.

These developments led the researchers to investigate whether SARS-CoV-2 infection could be playing a role in canine lung pathologies. The team also investigated whether domestic dogs are susceptible to infection in the home environment and whether they can contribute to community spread of the virus.

The team checked for the presence of SARS-CoV-2 infection and anti-SARS-CoV-2 antibodies in 40 dogs with pulmonary pathologies and 20 healthy dogs from households where at least one member was infected.

As reported in the journal Veterinary Research, all dogs included in the study tested negative for SARS-CoV-2 infection by real-time quantitative reverse transcription polymerase chain reaction PCR (RT-qPCR).

However, one of the 40 unhealthy dogs and five of the 20 healthy dogs tested positive for anti-SARS-CoV-2 antibodies.

The team says the findings suggest that that, even in cases of canine infection with SARS-CoV-2, the virus would be poorly transmissible.

More about coronaviruses in animals and humans


The novel SARS-CoV-2 virus belongs to the betacoronavirus genus, one of the four genera (alpha-, beta-, gamma- and delta-) that make up the coronavirus family.

The alpha- and betacoronaviruses, which infect both animals and humans, have also been detected in dogs and cats.

Mostly, they are responsible for respiratory infections in humans and gastroenteritis in animals,” says the researchers.

However, canine respiratory coronavirus (CRCoV), which is also a betacoronavirus, can cause respiratory symptoms in dogs and sometimes occurs as a coinfection with other respiratory pathogens.

SARS-CoV-2 infections have been reported in various different species

Since the SARS-CoV-2 outbreak began in Wuhan, China, in late 2019, many infections have been described in cats, dogs, tigers, lions, minks and ferrets, all of which were reported to have had close contact with infected people.

The team says that no cases of zoonotic SARS-CoV-2 transmission from domestic animals to humans have yet been described.

In fact, some studies have reported cases of dogs belonging to infected owners testing negative for anti- SARS-CoV-2 antibodies, suggesting that domestic dogs might not even be carriers of the virus.

By contrast, other studies have reported cases of companion dogs testing positive for SARS-CoV-2 infection by RT-qPCR.

“Dogs are currently considered to be less susceptible hosts for SARS-CoV-2 than cats or minks, despite the fact that several positive RT-qPCR test results in dogs have been reported,” say the researchers.

“However, veterinarians in Spain have observed an increase in aggressive lung pathologies in dogs during the human COVID-19 pandemic that have not responded to conventional antibiotic treatments,” they add.

What did the researchers do?

To determine whether SARS-CoV-2 might play a role in these pathologies, the team conducted a prospective study of 40 dogs (aged a mean of 8 years) presenting with pulmonary pathologies between April and June 2020 in Spain.

All of the animals underwent chest X-rays, ultrasound analysis, and computed tomography. This revealed severe alveolar or interstitial patterns with pulmonary opacity, parenchymal abnormalities, and bilateral lesions.

Nasopharyngeal and rectal swabs taken from the animals were tested for the presence of SARS-CoV-2 by RT-qPCR, and several immunoassays were performed to test for anti-SARS-CoV-2 antibodies.

A further healthy 20 dogs from households where at least one person had been diagnosed with SARS-CoV-2 were also tested.

What did the study find?

All 40 dogs presenting with lung pathologies, and all 20 healthy dogs tested negative for SARS-CoV-2 infection by RT-qPCR.

Thirty-three of the unhealthy dogs underwent further testing for infectious canine pathogens, which revealed infection with the bacterium Mycoplasma spp. in 26 cases.

SARS-CoV-2-specific immunoglobulin G (IgG) antibodies were detected more frequently among the healthy dogs from SARS-CoV-2-positive households than among the dogs with lung pathologies (five dogs versus one dog), which the team says might indicate the susceptibility of these exposed dogs to infection.

However, all six of the SARS-CoV-2-specific IgG-positive animals still tested negative for infection by RT-qPCR, the team points out.

Here we report that despite detecting dogs with anti-SARSCoV-2 IgG, we never obtained a positive RT-qPCR for SARS-SoV-2, not even in dogs with severe pulmonary disease; suggesting that even in the case of canine infection, transmission would be unlikely,” writes the team.

“Moreover, dogs with owners positive for SARS-CoV-2 could have been more likely to be exposed to infection during outbreak,” they conclude.

Journal reference:

Perisé-Barrios, AJ, et al. Humoral responses to SARS-CoV-2 by healthy and sick dogs during the COVID-19 pandemic in Spain. Vet Res 52, 22 (2021). https://doi.org/10.1186/s13567-021-00897-y, https://veterinaryresearch.biomedcentra ... 21-00897-y
trader32176
Posts: 2723
Joined: Fri Jun 26, 2020 5:22 am

Re: Airborne Dust / Zoonosis / Land Use

Post by trader32176 »

Evolution of the spike gene of SARS-CoV-2 for human adaptation

2/21/21


https://www.news-medical.net/news/20210 ... ation.aspx


The rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected over 111 million individuals worldwide and has resulted in the COVID-19 pandemic. Many pangolin and bat-derived viruses are closely related to SARS-CoV-2, which suggests its likely zoonotic origin.

Researchers have found a 96% similarity in nucleotide sequence between bat coronavirus (RaTG13), isolated in China, and SARS-CoV-2 and ~97% amino acid similarity with the Spike (S) protein. This S protein performs two essential roles, i.e., mediates receptor-binding and membrane fusion. Hence, spike protein is regarded as a key coronavirus determinant of host tropism.

Similarly, a high percentage of similarity was also found in viruses present in Manis javanica (pangolins). A 97.4% amino acid concordance has been reported to be present in the receptor-binding domain (RBD) of the spike protein found in the pangolin virus.

A study of various epidemics over a couple of decades, i.e., the emergence of swine acute diarrhea syndrome coronavirus (SADS-CoV), severe acute respiratory syndrome coronavirus (SARS-CoV), and Middle East respiratory syndrome coronavirus (MERS-CoV) have shown the world the epidemic potential of coronaviruses.

Scientists have explained that a minor change in the virus's genetic sequence may play a crucial role in its adaptation to a new host. A minor modification in only two amino acids established a necessary change in SARS-CoV and MERS-CoV spike proteins required to adapt to human beings.

A similar change was also found in many other viruses, such as Ebola, where a single alanine-to-valine mutation at position 82 in the glycoprotein initiated their human adaptation, which caused the outbreak. Many recent outbreaks associated with an RNA virus, for example, West Nile virus, Zika virus, and Chikungunya virus, also occurred due to a single amino acid change in the virus nucleotide sequence.

In the case of SARS-CoV-2, a single mutation at position 614 in the S protein caused a change in the production of single aspartic acid to glycine, which has resulted in an increase of replication vigor in humans. However, the genetic determinants of SARS-CoV-2 responsible for the change of its host from animal to human remained unknown.

Scientists believe a strong signature of positive selection occurs when a virus changes its host through rapid evolution or cross-species transmission.

Such incidence was reported for the brief SARS epidemic that took place in 2002–2003. During this period, a series of adaptive changes or mutations occurred in SARS-CoV genomes characterized based on dN/dS tests.

These tests are designed for the comparison of eukaryotic interspecies. However, the limitation of these tests is that they cannot detect the hallmark signature of positive selection in viral lineages with small sequence divergence.

Recently, researchers have used highly sophisticated methods that are capable of detecting selective sweeps. In this method, a selectively favorable mutation spreads through the population, causing a reduction in the level of sequence variability at nearby genomic sites.

With the help of unprecedented statistical tools, scientists have analyzed more than 182,000 SARS-CoV-2 genomes and found that positive selection plays a vital role in the adaptive evolution of SARS-CoV-2. Considering the coronavirus host tropism, researchers provided strong evidence that the spike protein residue 372 contributes to adaptive mutation, which in turn aggregates their replication in human lung cells. The research by scientists in the U.S and Israel is posted online on the bioRxiv* preprint server.

The genetic modification, i.e., threonine-to-alanine change, may enable the virus to replicate more vigorously within human cells. This also promotes an efficient human-to-human transmission.

Prior computation-based research and the study of pseudotyped viruses have identified positive selection in SARS-CoV-2.

Even though a study of the pseudoviruses provided vast volumes of useful information, the entire life cycle of the virus or the interactions between different viral proteins and the host were not obtained. Recently, the use of live viruses has helped the development of hamster models that recapitulate human-to-human transmission.

In summary, current research shows the presence of a distinct footprint of positive selection around a non-synonymous change (A1114G; T372A) within the RBD of the SARS-CoV-2 spike protein. This plays a vital role in incapacitating species barriers and also achieving interspecies transmission from animals to humans.

Further, the structural analysis also indicates that the change of threonine with alanine in SARS-CoV-2 removes the glycosylation site at N370. Such changes indicate a favorable binding of the virus to the cellular receptor in humans (ACE2).

Another interesting suggestion was that, unlike previous assumptions, the Huanan seafood market, China, might not be the origin point of the novel SARS-CoV-2. The transmission may have occurred unnoticed elsewhere for a period that provided the ancestor virus enough time for their adaptation to human replications.

*Important Notice


bioRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Journal reference:


A selective sweep in the Spike gene has driven SARS-CoV-2 human adaptation Lin Kang, Guijuan He, Amanda K. Sharp, Xiaofeng Wang, Anne M. Brown, Pawel Michalak, James Weger-Lucarelli bioRxiv 2021.02.13.431090; doi: https://doi.org/10.1101/2021.02.13.431090, https://www.biorxiv.org/content/10.1101 ... 3.431090v1
trader32176
Posts: 2723
Joined: Fri Jun 26, 2020 5:22 am

Re: Airborne Dust / Zoonosis / Land Use

Post by trader32176 »

Research predicts which mammal species can spread SARS-CoV-2

2/23/21


https://www.news-medical.net/news/20210 ... CoV-2.aspx


Scientists worldwide are fighting to contain the ongoing COVID-19 pandemic, which has already claimed more than 2.48 million lives. Preventing spillback infections is essential to containing the pandemic. To do so, it is vital to understand the nature of the virus, i.e., its susceptibility to a range of hosts.

Like previous disease outbreak episodes, SARS-CoV-2 originated from the spillover of a zoonotic pathogen. This virus's high transmission rate is attributed to its capability to use a highly conserved cell surface receptor, angiotensin-converting enzyme 2 (ACE2), to enter the host cell.

The ACE2 protein is predominantly present on the cell surface of all major vertebrate groups. The high rate of spillback infections in the past year can be explained by the simultaneous occurrence of three factors – (a) a high human population, (b) high infection potential of SARS-CoV-2, and (c) the ubiquitous nature of the ACE2 receptor.

Now, a new study, published on the bioRxiv* preprint server, has revealed the importance of spillback infections during pandemics. During spillback infections, the SARS-CoV-2 virus was observed to have been transmitted from humans (host) to other mammals. Such spillback infections may lead to the establishment of a new host (animals), which may act as a virus reservoir. These animals may, subsequently, cause a secondary spillover to humans.

Such an occurrence was found in Denmark and in the Netherlands, where SARS-CoV-2 was transmitted from humans to farmed mink, and afterward, a variant of the virus was transmitted back from the mink to humans.

The secondary spillover poses a significant threat as it generates mutant strains. A variety of pets, farmed animals, etc., are reported as new hosts of SARS-CoV-2. The emergent strains may be more virulent than the existing ones. A prior study of the recent spillover event has revealed that the mink-derived variant can decrease sensitivity to neutralizing antibodies. This indicates that the efficacy of vaccines may also take a toll.

Scientists have carried out various computational studies to make valid predictions about non-human animals susceptible to SARS-CoV-2. To this end, both comparative models of ACE2 orthologs sequences among various species and structure-based models of the viral spike protein bound to ACE2 orthologs were used.

The current study develops a new model by combining structure-based inference with species-level trait data. This would help predict the zoonotic capacity of different animal species in becoming zoonotic hosts of SARS CoV-2.

To enhance the predictive capacity of the models across species, scientists have incorporated intrinsic biological traits of ~5400 mammal species in their study.

In the course of model development, several factors that are associated with species susceptibility to SARS-CoV-2 were considered, for example, the binding strength between SARS-CoV-2 receptor binding domain and host ACE2. The combined modeling system has helped increase the accuracy percentage of prediction of zoonotic capacity to 72%.

The model has predicted a high SARS-CoV-2 zoonotic capacity for many domesticated, farmed, and live traded animal species. For example, among all livestock, Bubalus bubalis (water buffalo) was predicted to have a high zoonotic capacity. Some of the other species that showed a high percentage of zoonotic capacity are rats, rodents, and bats. Endangered species such as mountain gorillas and addax also have a high zoonotic capacity, thereby putting the individuals directly involved in active conservation management at greater risk of spillback transmission. The model has also helped to identify various other animal species that can act as hosts to SARS-CoV-2.

Despite a high level of agreement between these models and empirical studies' predictions, some differences remain between the computational results and the actual experiments, including animals. As an example, several computational predictions suggested that Sus scrofa (pigs) show susceptibility to SARS-CoV-2, but this result did not hold up in animal-based experiments.

Scientists believe that the disagreement between the real-world observations and in silico predictions of zoonotic capacity stems from the fact that the host susceptibility and transmission capacity are not the sole determinants. Transmission of the virus also depends upon the host's cellular environments, i.e., host immunogenicity, protein receptors, etc., where the virus's replication takes place. Further, other challenges such as limitations in the ACE2 sequences and species trait data also aid in predicting error.

Therefore, researchers have recommended that a single methodology is not sufficient to predict the zoonotic capacity of SARS-CoV-2. The zoonotic predictive capacity could be increased by assessing the results obtained from combining theoretical models, statistical models, laboratory experiments, and real-world observations.

*Important Notice

bioRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Journal reference:

Predicting the zoonotic capacity of mammal species for SARS-CoV-2 Ilya R. Fischhoff, Adrian A. Castellanos, João P.G.L.M. Rodrigues, Arvind Varsani, Barbara A. Han bioRxiv 2021.02.18.431844; doi: https://doi.org/10.1101/2021.02.18.431844, https://www.biorxiv.org/content/10.1101 ... 8.431844v1
trader32176
Posts: 2723
Joined: Fri Jun 26, 2020 5:22 am

Re: Airborne Dust / Zoonosis / Land Use

Post by trader32176 »

Free-ranging minks exhibit high titers of SARS-CoV-2 antibodies in Utah

2/28/21


https://www.news-medical.net/news/20210 ... -Utah.aspx


Zoonotic diseases have caused outbreaks and epidemics throughout history. The current coronavirus disease (COVID-19) pandemic is one of the worst pandemics in the world.

The coronavirus pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), first emerged in Wuhan City, China. The outbreak was reported in a seafood market, where wildlife trade occurs. One of the virus's potential intermediate hosts is the pangolin, which may have acquired the virus from bats.

Apart from pangolins, camels, and civet cats, another possible host of the virus are minks.

Researchers at the U.S. Centers for Disease Control and Prevention (CDC) report outbreaks of coronavirus disease (COVID-19) on mink farms in Utah, United States. They surveyed around farms for evidence of exposure and found high SARS-CoV-2 titers, suggesting a possible viral transmission pathway to native wildlife.

Wildlife epidemiologic investigation

The researchers reported a wildlife epidemiologic investigation of mammals captured on or near properties in Utah, where outbreaks of SAR-CoV-2 were assumed to occur in farmed mink.

Mink farming is a popular and common industry in the U.S. Most of the farms are family-owned. Amid the coronavirus pandemic, the U.S. Department of Agriculture's Veterinary Services Laboratories confirmed SARS-CoV-2 infection in mink at two Utah farms in August 2020.

From there, more outbreaks were confirmed at many farms not only in Utah but also in Wisconsin, Michigan, and Oregon. Although epidemiologic investigations are being processed, scientists believe that infected farmworkers are the potential source of the virus.

The study

To arrive at the study, published in the CDC's Emerging Infectious Diseases journal, the team captured free-roaming mammals from August 22 to 30, 2020. They used Tomahawk and Sherman traps placed outside barns and barrier fences.

The team obtained oral, nasal, rectal swabs, blood samples, and tissue specimens from the animals. All the samples collected were sent to the National Veterinary Services Laboratories, while tissue specimens were sent to the U.S. Geological Survey National Wildlife Health Center for testing.

SARS-CoV-2 viral RNA was tested in the samples by real-time reverse transcription-polymerase chain reaction (RRT-PCR). Virus neutralization assays were used to test serum samples.

Overall, the team captured 102 mammals, 78 are rodents and 24 are mesocarnivores. Rodent species composed of 45 deer mice, 5 Peromyscus spp. Mice, 25 house mice, and 3 rock squirrels. Mesocarnivore species consisted of presumed escaped American mink, 2 presumed wild American mink, 5 raccoons, and 6 striped skunks.

Of the minks captured, 11 tested positive for SARS-CoV-2 antibodies. No other animals had detectable antibody responses. This means that the minks were previously exposed to SARS-CoV-2 and got infected.

Of those minks with a positive result, three had a high cycle threshold detection.

"Although we did not find evidence for SARS-CoV-2 establishment in wildlife, the discovery of escaped mink with the opportunity to disperse and interact with susceptible wildlife, such as wild mink or deer mice, is concerning," the researchers explained in the study.

Escaping minks into the wildlife may pose a threat to wild minks. Since they are susceptible to SARS-CoV-2 infection, they can be potential reservoirs of the virus. This could lead to future outbreaks of COVID-19, which has now infected over 28.6 million cases in the U.S. alone, with more than 513,000 deaths.

"Heightened biosecurity and best management practices would help prevent accidental releases of infected animals or spillover of SARS-CoV-2 from susceptible species to native wildlife," the researchers added.

Reverse zoonosis could also play a role in the spread of viruses. It involves the transmission of a virus from humans to animals. Since the spread could pose health threats to both humans and animals, wildlife and farm surveillance of minks is crucial.

Source:

COVID-19 Dashboard by the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University (JHU) - https://gisanddata.maps.arcgis.com/apps ... 7b48e9ecf6

Journal reference:

Shriner, S., Ellis, J., Root, J. et al. (2021). SARS-CoV-2 Exposure in Escaped Mink, Utah, USA. Emerging Infectious Diseases. https://wwwnc.cdc.gov/eid/article/27/3/20-4444_article
trader32176
Posts: 2723
Joined: Fri Jun 26, 2020 5:22 am

Re: Airborne Dust / Zoonosis / Land Use

Post by trader32176 »

Time to implement measures preventing future viral zoonoses

2/28/21


https://www.news-medical.net/news/20210 ... noses.aspx


The coronavirus disease (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), continues to spread globally, infecting over 114 million people. The virus first emerged in late December 2019 in Wuhan, China, from a potential animal host.

Zoonotic diseases have caused outbreaks throughout history, claiming millions of lives. These diseases occur when pathogens from animals jump to humans and cause illness.

Now, researchers at the University of Silesia in Katowice and the Poznan University of Medical Sciences in Poland recommend measures to prevent future zoonotic outbreaks. They emphasized the importance of viral surveillance and research on new viral strains as primary strategies to combat these infections.

The coronavirus pandemic

The coronavirus pandemic first emerged in Wuhan City, China in December 2019. Since then, it has spread to 192 counties and regions. It has caused a significant burden to healthcare systems, the economy, and public fears.

The pandemic served as a lesson and call-to-action for many countries and health agencies to minimize the risk of future viral pandemics. Acting early when an outbreak surface is crucial to reduce the negative impact of the illness.

Zoonotic viral infections

Zoonotic viral infections represent a critical global health issue. Due to various reservoirs and vectors, it is challenging to track transmission dynamics and impose control and preventive measures.

Throughout history, some of the worse outbreaks the world has experienced were diseases that came from animals. These include the H1N1 swine flu, bubonic plaque, coronavirus outbreaks like severe acute respiratory syndrome (SARS), the Middle East respiratory syndrome (MERS), and the current COVID-19, and the human immunodeficiency virus (HIV) infection, among others.

The spillover of viruses and pathogens from animals to humans and from human to human is extremely rare. However, spillover events can occur and cause widespread infections.

The study

The current study, published in the journal Science of The Total Environment, highlights several directions through which the transmission and spread of pathogens from animals to humans can be prevented or mitigated.

Further, the study elaborated on the role of surveillance systems. It also explains the importance of identifying viral pathogens in animals, reducing ferret farming, changes to wild trade regulations, modifications to the meat production process, and limitations to hunting activities.

The study explains how monitoring and identifying novel viral agents can help reduce outbreaks in the future. Surveillance of viral groups tied to animal hosts is essential in understanding current and future epidemiological risks.

Past studies point to the zoonotic origin of SARS-CoV-2, with bats being the primary reservoir for its lineage. From bats, scientists believe the virus jumped to an intermediate host before infecting humans. The intermediate host speculated to have transmitted the virus to people in the seafood market in Wuhan City was a pangolin.

In previous coronavirus outbreaks, like SARS and MERS, the intermediate hosts were noted to be civet cats and camels, respectively. Considering this, there is an urgent need to continue to screen the bat-associated coronaviruses, identify hotspots, isolate particular strains, and evaluate their potential for cross-species transmission. All these will help prevent another outbreak in the future, which may evolve into a pandemic.

The study also highlights the importance of limiting wildlife trade to prevent future zoonotic outbreaks. Today, the international trade of wild animals is currently regulated, wherein countries can implement provisions. However, due to the illegal wildlife trade, the risk of another pandemic is possible.

Hence, limiting or banning wildlife trade is essential. Countries can also regulate illegal trades happening in their territories to protect not only animals but also people.

The study also discussed mink farming as a potential source of zoonotic diseases. It is known that species from the Mustelidae family are vulnerable to the infection of beta-coronaviruses. Ferrets are usually used as animal models for coronavirus studies.

Meanwhile, the American mink is also susceptible to some coronaviruses, such as SARS-CoV-2. Today, the highest production of mink is Denmark, China, the Netherlands, Russia, and the United States.

Though the worldwide resignation from mink farming is unlikely in the future, some areas have noted its decline. Such decisions will have a positive ecological impact since mink production has been tied to increased nitrous oxide (N2O) emissions, eutrophication, and water consumption.

Other factors that may drive future outbreaks include meat production and hunting activities. Changing practices and regulating these activities can reduce the risk of future coronavirus outbreaks.

“The present paper considers different strategies, the implementation of which would not only be beneficial from a healthcare point of view but in selected cases could also have positive socio-economic, ethical, and environmental outcomes,” the researchers concluded in the study.

Source:

COVID-19 Dashboard by the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University (JHU) - https://gisanddata.maps.arcgis.com/apps ... 7b48e9ecf6

Journal reference:

Halabowski, D., and Rzymski, P. (2021). Taking a lesson from the COVID-19 pandemic: Preventing the future outbreaks of viral zoonoses through a multi-faceted approach. Science of The Total Environment. https://www.sciencedirect.com/science/a ... via%3Dihub#!
trader32176
Posts: 2723
Joined: Fri Jun 26, 2020 5:22 am

Re: Airborne Dust / Zoonosis / Land Use

Post by trader32176 »

Zoonotic Implications of Onchocerca Species on Human Health

9/17/20


https://pubmed.ncbi.nlm.nih.gov/32957647/

Abstract

The genus Onchocerca includes several species associated with ungulates as hosts, although some have been identified in canids, felids, and humans. Onchocerca species have a wide geographical distribution, and the disease they produce, onchocerciasis, is generally seen in adult individuals because of its large prepatency period. In recent years, Onchocerca species infecting animals have been found as subcutaneous nodules or invading the ocular tissues of humans; the species involved are O. lupi, O. dewittei japonica, O. jakutensis, O. gutturosa, and O. cervicalis. These findings generally involve immature adult female worms, with no evidence of being fertile. However, a few cases with fertile O. lupi, O. dewittei japonica, and O. jakutensis worms have been identified recently in humans. These are relevant because they indicate that the parasite's life cycle was completed in the new host-humans. In this work, we discuss the establishment of zoonotic Onchocerca infections in humans, and the possibility of these infections to produce symptoms similar to human onchocerciasis, such as dermatitis, ocular damage, and epilepsy. Zoonotic onchocerciasis is thought to be an emerging human parasitic disease, with the need to take measures such as One Health Strategies, in order to identify and control new cases in humans.


Onchocerciasis caused by Onchocerca lupi: an emerging zoonotic infection. Systematic review


5/20/15

https://pubmed.ncbi.nlm.nih.gov/25990062/

Abstract

Globalization has increased circulation of people, their food, livestock and pets in the world, and changes in the environment, climate and human behaviour have led to the rapid expansion of emerging infections throughout the world. One of the reasons of a new pathogen affecting humans is the passage from an animal to a human being. Onchocerca (O.) lupi, a filarial worm first described in a wolf in 1967, is an emerging pathogen which has been incriminated as the etiological agent for 205 canine, 2 feline and 18 human infections in Europe, Tunisia, Turkey, Iran and the USA. Most frequent findings in animals and humans are monolateral or asymmetrical variably painful subconjunctival swellings and nodules containing immature or mature worms affecting the eye and/or adjacent tissues accompanied by conjunctival hyperemia. Occasionally, subcutaneous nodules and masses affecting the spinal cord have been observed in humans. Diagnosis of O. lupi is achieved by microscopy of excised adult female worms which exhibit a particular cuticular structure and molecular analysis. Treatment consists in worm removal accompanied by antihelminthic, antibiotic and anti-inflammatory therapy.


Everything You Should Know About Onchocerciasis (River Blindness)

https://www.healthline.com/health/oncho ... lindness#1

What is onchocerciasis?


Onchocerciasis, also known as river blindness, is a disease that affects the skin and eyes. It’s caused by the worm Onchocerca volvulus.

Onchocerca volvulus is a parasite. It’s spread to humans and livestock through the bite of a type of blackfly from the genus Simulium. This type of blackfly is found near rivers and streams. That’s where the name “river blindness” comes from.

Read on to learn more about this condition.

Symptoms

There are different stages of onchocerciasis. In earlier stages, you may not have any symptoms. It can take up to a year for symptoms to appear and the infection to become apparent.

Once the infection becomes severe, symptoms may include:


skin rashes
extreme itching
bumps under the skin
loss of skin elasticity, which can make skin appear thin and brittle
itching of the eyes
changes to skin pigmentation
enlarged groin
cataracts
light sensitivity
loss of vision


In rare cases, you may also have swollen lymph glands.

Causes

You can develop river blindness if you’re bitten repeatedly by infected female blackflies. The blackfly passes the larvae of the worm Onchocercidae through the bite. The larvae move to the subcutaneous tissue of your skin, and mature into adult worms over 6 to 12 months. The cycle repeats when a female blackfly bites a person infected with onchocerciasis and ingests the parasite.

Adult worms can live for 10 to 15 years and may produce millions of microfilariae during that time. Microfilariae are baby or larval worms. Symptoms appear when microfilariae die, so symptoms can continue to worsen the longer you are infected. The most extreme, longest-lasting cases result in blindness.

Risk factors

You’re at increased risk for onchocerciasis if you live near fast-running streams or rivers in intertropical areas. That’s because blackflies live and breed in these areas. Ninety percentTrusted Source of cases are in Africa, but cases have also been identified in Yemen and in six countries in Latin America. It’s unusual for casual travelers to contract the disease because repeated bites are necessary for the infection to be transmitted. Residents, volunteers, and missionaries in areas of Africa are at the greatest risk.
trader32176
Posts: 2723
Joined: Fri Jun 26, 2020 5:22 am

Re: Airborne Dust / Zoonosis / Land Use

Post by trader32176 »

Study highlights urgent need to monitor legal wildlife trade to reduce emerging zoonotic diseases

3/5/21


https://www.news-medical.net/news/20210 ... eases.aspx


With three out of four newly emerging infectious human diseases originating in animals, there is an urgent need to monitor the legal trade in wildlife, according to new research by Vincent Nijman, Professor in Anthropology at Oxford Brookes University.

Professor Nijman, who has been involved in monitoring and regulating the legal wildlife trade for over two decades, said: "Covid-19 more than anything else has put a spotlight on emerging infectious diseases and how this is linked to the trade in wild animals. Few people are aware of its scale. With literally hundreds of millions of live wild animals being shipped around the world each year, it seems unlikely that diseases are spread through illegal channels only. After all, parasites, bacteria, and viruses do not read legal documents or check if they have received the correct stamp."

Dangerous to only focus on the illegal wildlife trade

The illegal wildlife trade is often seen as one of the major gateways to zoonotic diseases, that spread from animals to humans.

While the illegal trade in tigers, ivory, rhino horn, pangolins, and primates is of paramount concern for public health, Professor Nijman says the legal wildlife trade should be of equal concern: "Given that in many instances the legal wildlife trade is several orders of magnitude larger than the illegal trade, it is ineffective and possibly dangerous to focus on the illegal wildlife trade only."

Lack of hygiene in wet markets could drive infection transmission

The Covid-19 pandemic threw attention onto wet markets, now associated closely with zoonotic diseases. But in the wet market of Wuhan, the vast majority of non-domesticated animals (crocodiles, bats, civets, bamboo rats) were legally offered for sale. Professor Nijman notes that "a lack of appropriate hygiene conditions (handwashing, sanitation, separation of wildlife and their parts), make wildlife markets drivers for the transmission of infections."

" This study clearly illustrates that there are incredibly serious risks associated with the trade-in wildlife, regardless of whether the species involved are traded legally or illegally. Clearly the risk of spreading harmful zoonotic disease must be considered when regulating the trade in wildlife, and much more research and preventative measures are essential if we are to avoid further pandemics."

- Dr. Chris R. Shepherd, Expert on Wildlife Trade and Executive Director of the Monitor Conservation Research Society

Source:

Oxford Brookes University

Journal reference:


Nijman, V. (2021) Illegal and Legal Wildlife Trade Spreads Zoonotic Diseases. Trends in Parasitology. doi.org/10.1016/j.pt.2021.02.001.
trader32176
Posts: 2723
Joined: Fri Jun 26, 2020 5:22 am

Re: Airborne Dust / Zoonosis / Land Use

Post by trader32176 »

How do viruses evolve in bats?

3/8/21


https://www.news-medical.net/news/20210 ... -bats.aspx


Bats have played a crucial epidemiological role in the evolution of many viruses and house many coronaviruses. Until 2002, coronaviruses had been known to cause mild respiratory ailments in human beings. However, this notion changed in the same year when a bat-borne virus caused the severe acute respiratory syndrome (SARS) pandemic.

Seventeen countries were severely affected, with the fatality rate for patients above 60 years reaching 50%. This epidemic was followed by the middle east respiratory syndrome (MERS) epidemic in 2012 and, finally, the current pandemic that had spread to 192 countries and territories by the end of 2020.

It is believed that bats were involved in each of these three episodes, although direct evidence regarding bats' role in the current pandemic is still lacking.

The immune system of bats can tolerate the invasion of viruses for several months without developing clinical signs. A current review article published in the journal Environmental Science and Pollution research discusses coronaviruses' role in epidemics and the epidemiological role of bats. The paper also presents evidence (phylogenetic data, animal experiments, etc.) that help establish the role of bats in the epidemiology of the current pandemic.

Bats represent about one-fifth of mammalian diversity and have more than 1,400 species. They are nocturnal and are the only mammals capable of sustained flight. Bats live in large dense populations up to 3,000 bats/m2. This proximity makes it easy for viruses to be transmitted across the roosts and spillover into other animals. Bats act as a natural reservoir for various zoonotic viruses and pose a severe threat to public health.

The epidemiological role of bats was first uncovered in 1920 when they were found to spread rabies and other viruses among livestock and human beings. The role of bats was confirmed once again in 1994 during the spread of the Hendra virus among horses and Nipah, SARS and filoviruses among humans. Subsequently, bats were examined, and researchers found the presence of many viruses, including known families like Rhabdoviruses and coronaviruses.

Other researchers have shown that the simultaneous presence of various viral genomes in bats fosters the development of many new and unknown mutated strains.

There are a few key reasons why bats play such a critical epidemiological role. Firstly, bats live long and can fly over long distances. These factors aid in the horizontal and vertical spread of viruses, i.e., among bats and from bats to humans. Secondly, bats live in a densely populated manner. Millions of bats may live in caves, trees, or also human-made buildings. This makes bat-to-human transmission a real possibility. Third, bats have a modified metabolic system. When bats fly, the body temperature rises, which activates their immune system, much like a fever in humans. This raises the tolerance of bats to a wide variety of viruses. Lastly, the viruses and bats have a co-evolutionary relationship and this has enabled their coexistence in an equilibrium. The adaptation of the bats' immune system includes multiple immunoglobulins, varied responses to antibodies, interferons, receptor recognition, etc. These factors make bats the ideal virus reservoirs.

The simultaneous presence of many coronaviruses in bats enables their recombination, mutations, and emergence of new diseases. Scientists have compared the genome structures of humans and bats and noted that the immune system of bats has bat-specific transcripts. The human genome has 7% immune genes, while bats have 2.75 – 3.5%. Bats have a unique mechanism to limit inflammatory responses induced by viruses and maintain type 1 IFN responses to prevent the spread of the virus. The bat genome contains only 3 IFN type 1 alpha genes important for antiviral pathways and innate immunity. The high level of interferon in unstimulated bat cells also protects against viruses.

When bats are infected by coronaviruses, they produce lower levels of IL-1β secretion and ASC (an apoptosis-associated speck-like protein containing a CARD) than other mammals. This does not prevent viral propagation. This makes bats unique mammals that can serve as a vast genomic pool from where novel human coronaviruses may emerge. Most researchers consider bats as the source of SARS-CoV2. A recent phylogenetic study showed that the bat coronavirus 3CLpro is 99.02% identical to SARS-CoV2.

The current research reviews the role of bats as a natural reservoir for many viruses, including coronaviruses. It is vital to understand the immunological and physiological factors that enable bats to play this public health-threatening role. It will help us in the early detection, prevention, efficient management, and control of future pandemics. Various novel therapeutic approaches could be developed if we understood the mechanisms by which bats can prevent virus protein-mediated modulation after the viral invasion.

Journal reference:

El-Sayed, A., Kamel, M. Coronaviruses in humans and animals: the role of bats in viral evolution. Environ Sci Pollut Res (2021). https://doi.org/10.1007/s11356-021-12553-1, https://link.springer.com/article/10.10 ... 21-12553-1
trader32176
Posts: 2723
Joined: Fri Jun 26, 2020 5:22 am

Re: Airborne Dust / Zoonosis / Land Use

Post by trader32176 »

Newly-discovered bat coronavirus 94.5% identical to SARS-CoV-2

3/10/21


https://www.news-medical.net/news/20210 ... CoV-2.aspx


Researchers in China and Australia have reported the discovery of novel bat coronaviruses that further reveal the diversity and complex evolutionary history of these viruses.

In early 2020, the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified as the causative agent of the coronavirus disease 2019 (COVID-19) outbreak that first began in Wuhan, China, in late December 2019.

A combination of genome sequencing and sampling studies then identified a number of SARS-CoV-2-related coronaviruses in wildlife species that together pointed to underestimation of the phylogenetic and genomic diversity of coronaviruses.

Now, Weifeng Shi from Shandong First Medical University & Shandong Academy of Medical Sciences in Taian, China and colleagues have conducted a meta-transcriptomic analysis of samples collected from 23 bat species in Yunnan province in China during 2019 and 2020.

“Our study highlights both the remarkable diversity of bat viruses at the local scale and that relatives of SARS-CoV-2 and SARS-CoV circulate in wildlife species in a broad geographic region of Southeast Asia and southern China,” says the team.

“These data will help guide surveillance efforts to determine the origins of SARS-CoV-2 and other pathogenic coronaviruses.”

A pre-print version of the research paper is available on the bioRxiv* server, while the article undergoes peer review.

Bats are well-known hosts of coronaviruses

Bats are well-established hosts to a broad range of viruses that are known to cause severe disease in humans, including the Hendra virus, Ebola virus and, most notably, coronaviruses.

Four of the seven known human coronaviruses have zoonotic origins. These include the SARS-CoV virus responsible for the 2002 to 2004 SARS outbreak and the Middle East respiratory coronavirus (MERS-CoV) responsible for numerous outbreaks of severe respiratory illness across the Middle East since 2012.

Although bats are the most likely hosts of these coronaviruses, their emergence in humans has also sometimes involved “intermediate” hosts such as the palm civet (in the case of SARS-CoV) and dromedary camels (MERS-CoV).

In early 2020, the novel SARS-CoV-2 virus was identified as the causative agent of a pneumonia outbreak in Wuhan, China, that quickly turned into a global pandemic.

A combination of retrospective genome sequencing and sampling studies identified a number of SARS-CoV-2-related coronaviruses in wildlife species.

These included the RaTG13 virus found in the Rhinolophus affinis bat, which is the closest known relative of SARS-CoV-2 across the viral genome as a whole.

SARS-CoV-2-related viruses have also been identified in various other Rhinolophid bats, including R. shameli bats sampled in Cambodia, R. cornutus bats sampled in Japan, and R. acuminatus bats sampled in Thailand.

“Collectively, these studies indicate that bats across a broad swathe of Asia harbor coronaviruses that are closely related to SARS-CoV-2 and that the phylogenetic and genomic diversity of these viruses has likely been underestimated” says Shi and the team.

What did the researchers do?


To further investigate the diversity, ecology, and evolution of bat viruses, Shi and colleagues conducted a meta-transcriptomic study of 411 samples collected from 23 bat species in a small (~1100 hectare) region within Yunnan province China, between May 2019 and November 2020.

The team identified coronavirus contigs (sets of overlapping DNA sequences) in 40 of 100 sequencing libraries, including seven libraries with contigs that could be mapped to SARS-CoV-2.

The team obtained novel coronavirus genomes

From these data, the researchers assembled 24 full-length novel coronavirus genomes, including four genomes related to SARS-CoV-2 and three related to SARS-CoV.

Notably, one of these novel bat coronaviruses – RpYN06 – exhibited 94.5% sequence identity to SARS-CoV-2 across the whole genome. Furthermore, in some individual genes (ORF1ab, ORF7a, ORF8, N, and ORF10), RpYN06 was the closest relative of SARS-CoV-2 identified to date.

However, at the genomic scale, low sequence identity in the spike gene made RpYN06 the second closest relative of SARS-CoV-2, next to RaTG13. The spike protein is the main structure SARS-CoV-2 uses to bind to and infect host cells.

Differences in the overall sequence of the spike gene

The researchers say that although several SARS-CoV-2-like viruses have previously been identified in different wildlife species, none are highly similar (>95% ) in the overall sequence identity of the spike gene.

Indeed, while the other three SARS-CoV-2-related viruses identified here were almost identical in sequence, the spike protein sequences formed an independent lineage that was separated from known sarbecoviruses by a relatively long branch. Sarbecovirus is a viral subgenus or the coronaviruses that SARS-CoV-2 and SARS-CoV belong to.

“Collectively, these results highlight the extremely high, and likely underestimated, genetic diversity of the sarbecovirus spike proteins, which likely reflects their adaptive flexibility,” writes Shi and colleagues.

The researchers say studies have previously shown that host switching of coronaviruses among bats is a frequent occurrence.

“That individual bat species can harbor multiple viruses increases the difficulty in resolving the origins of SARS-CoV-2 and other pathogenic coronaviruses,” they add.

What else did the study find?


Ecological modeling predicted the co-existence of up to 23 species of Rhinolophus bats species across much of Southeast Asia and southern China, with the largest hotspots for high bat diversity extending from South Lao and Vietnam into southern China.

The researchers say that in addition to Rhinolophids, this broad geographic region in Asia is also rich in many other bat families and other wildlife species that have been shown to be susceptible to SARS-CoV-2 in vitro.

“It is, therefore, essential that further surveillance efforts should cover a broader range of wild animals in this region to help track ongoing spillovers of SARS-CoV-2, SARS-CoV and other pathogenic viruses from animals to humans,” they conclude.

*Important Notice

bioRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Journal reference:

Shi W, et al. Identification of novel bat coronaviruses sheds light on the evolutionary origins of SARS-CoV-2 and related viruses. bioRxiv. 2021. doi: https://doi.org/10.1101/2021.03.08.434390
trader32176
Posts: 2723
Joined: Fri Jun 26, 2020 5:22 am

Re: Airborne Dust / Zoonosis / Land Use

Post by trader32176 »

SARS-CoV-2 did not change much when it jumped from bats to human hosts

3/13/21


https://www.news-medical.net/news/20210 ... hosts.aspx


How much did SARS-CoV-2 need to change in order to adapt to its new human host? In a research article published in the open access journal PLOS Biology Oscar MacLean, Spyros Lytras at the University of Glasgow, and colleagues, show that since December 2019 and for the first 11 months of the SARS-CoV-2 pandemic there has been very little 'important' genetic change observed in the hundreds of thousands of sequenced virus genomes.

The study is a collaboration between researchers in the UK, US and Belgium. The lead authors Prof David L Robertson (at the MRC-University of Glasgow Centre for Virus Research, Scotland) and Prof Sergei Pond (at the Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia) were able to turn their experience of analysing data from HIV and other viruses to SARS-CoV-2. Pond's state-of-the-art analytical framework, HyPhy, was instrumental in teasing out the signatures of evolution embedded in the virus genomes and rests on decades of theoretical knowledge on molecular evolutionary processes.

This does not mean no changes have occurred, mutations of no evolutionary significance accumulate and 'surf' along the millions of transmission events, like they do in all viruses." Some changes can have an effect; for example, the Spike replacement D614G which has been found to enhance transmissibility and certain other tweaks of virus biology scattered over its genome. On the whole, though, 'neutral' evolutionary processes have dominated.

" This stasis can be attributed to the highly susceptible nature of the human population to this new pathogen, with limited pressure from population immunity, and lack of containment, leading to exponential growth making almost every virus a winner."

- Dr Oscar MacLean, First Author

Pond comments, "what's been so surprising is just how transmissible SARS-CoV-2 has been from the outset. Usually viruses that jump to a new host species take some time to acquire adaptations to be as capable as SARS-CoV-2 at spreading, and most never make it past that stage, resulting in dead-end spillovers or localized outbreaks."

Studying the mutational processes of SARS-CoV-2 and related sarbecoviruses (the group of viruses SARS-CoV-2 belongs to from bats and pangolins), the authors find evidence of fairly significant change, but all before the emergence of SARS-CoV-2 in humans. This means that the 'generalist' nature of many coronaviruses and their apparent facility to jump between hosts, imbued SARS-CoV-2 with ready-made ability to infect humans and other mammals, but those properties most have probably evolved in bats prior to spillover to humans.

Joint first author and PhD student Spyros Lytras adds, "Interestingly, one of the closer bat viruses, RmYN02, has an intriguing genome structure made up of both SARS-CoV-2-like and bat-virus-like segments. Its genetic material carries both distinct composition signatures (associated with the action of host anti-viral immunity), supporting this change of evolutionary pace occurred in bats without the need for an intermediate animal species."


Source:

PLOS

Journal reference:

MacLean, O.A., et al. (2021) Natural selection in the evolution of SARS-CoV-2 in bats created a generalist virus and highly capable human pathogen. PLOS Biology. doi.org/10.1371/journal.pbio.3001115.
Post Reply