Human beings including with other organisms are being affected by emerging diseases from thousands of years. The microbes are the main reasons for the diseases. These Diseases are as dangerous as they take away the life of individual. Examples are Small pox, Polio and anthrax etc. are the dangerous and epidemic diseases. These diseases took away many lives and troubled mankind for thousands of years. At last vaccination was invented for them which were great achievements in science field. Even though there is lot of technology developed and huge no. of vaccines present in market still mankind is suffering with novel diseases which are emerging and widely spreading across the world. These are caused mainly by emerging microbes. New emerging microbes are being discovered in many new diseases. The causes for emerging microbes maybe environment, mankind non-worthy experiments and faults or may be because of mutations in the microbes.
EMERGING DISEASES: DESCRIPTION, SOURCE AND SPREAD
Emerging infections are caused by microbes but microbes are present or established in the animals and animal to human transmission of infection is called as Zoonotic infection or Zoonosis. Mainly viruses are present in the animal's vertebrae, saliva gastric glands, blood. Cattle, sheep, pets are responsible of carrying of emerging infections.
If emerging infections are increasing means something has changed in the lifestyle of human being, changes in the environment, Technical advances and growth of urban areas and consumption of the new organisms. In the survey report it has been proved that eating Pork, Beef can cause many infectious diseases.
There are few more factors which are responsible for emerging of microbial diseases they are:
- Microbial adaptation
- Climate and environment
- Technology and products
- Non-natural activities
In 21 century along with viruses like West Nile virus and Monkey pox virus there are few more emerging diseases caused by unknown virus like Ebola and Marburg hemorrhagic fevers, bovine spongiform encephalopathy (BSE), SARS and avian influenza. Emerging microbial diseases occurs from unknown microbes and previously known microbes.
Some microorganisms found to be resistant to antimicrobial agents. Examples are vancomycin-resistant enterococci (VRE), methicillin-resistant Staphylococcus aureus (MRSA).
Ebola and Marburg viruses: these viruses belong to filovirus family. They are responsible for causing hemorrhagic fevers and the death rate is high. There is no specific treatment for this disease. This virus infection was first identified in 1976 in Sudan and Zaire. It was also found in Philippines later in 2001 it was recorded in Uganda with causing 224 deaths. Then its emergence continued and also observed in 2005 and Marburg virus is more dangerous and seems to cause more deaths. These viruses transmit from one person to other through blood, semen and body fluids of human and animals. There is no treatment for this but proper covering of mouths and following proper nursing techniques can prevent spreading of this virus.
Monkey Pox Virus:
In Wisconsin a three year old kid by name kautzer was suffering with a disease and symptoms seem to be same like small pox, a 40yr old lady by name whitmarsh developed symptoms similar to flu with some lesions on head and under the arms. In a veterinary hospital two employees were found with same symptoms. The reason they all got infected by some unknown virus which was present in prairie dogs. The 3yr kid had brought that as pet, the lady was pet owner and employees in clinic had treated that sick dog. In all these three cases the dog type was same. When the blood samples of all of the victims have tested, they found that disease was new and ever before encountered and the name of the virus is Monkey pox. It belongs to group of orthopox virus. This is little severe than smallpox. This disease is mainly found in Africa. It killed 1%-10% of people affected. Country health board informed that for this disease there is no treatment and small pox vaccine should be used for this disease and be careful when using this vaccine and for precautions contact local board and health committees. How far this virus travelled? This is disease is also found in western hemisphere and also some countries including with United States.
West Nile Virus:
West Nile Virus is one more emerging microbe which is responsible for hemorrhage in brain and it is again emerging in 21st century in some places.
In 1999, Health department of New York had done tests in encephalitis patients suffering with brain inflammation. The tests revealed a virus West Nile Virus. This virus was never seen before.
This virus was even spread to United States. Scientists have found a great thing about this virus that replication or growth of this this virus depends on the outside temperature. This is the thermal virus which grows at high temperature of 70 degree Fahrenheit. At 70 degrees it takes 3 weeks, at 80 and 90 degrees it takes 2 and a week to develop into adult. This virus also infects squirrels, alligators, birds, rhinos, Humans etc. Main vector for transmitting this virus is Mosquito. When mosquito bites infected bird with this virus, this virus enters into saliva and when it bites human beings it enters the body of human beings and causes inflammation in brain which leads to death. Research found that in year 1999, in 4 states 62 were infected and 7 were died. In three years it is widely spread and 284 deaths occurred. In year 2010, 34 deaths occurred.
Symptoms of this disease are fever, severe headache, body aches, skin rashes or swollen lymph glands.
There is no better treatment for this diseases, best thing is to using mosquito repellants and preventing mosquito bite.
The Research enterprise has moved rapidly to respond to West Nile virus. Scientists have created a chimeric vaccine against West Nile virus. Genes coding for the immunodominant antigens of the West Nile virus (a flavivirus) were spliced into the genome of an attenuated yellow fever virus (another flavivirus) vaccine to produce a chimeric yellow fever/West Nile virus vaccine. This vaccine is now in clinical trials with early results. A similar chimeric vaccine has also been created with altering dengue virus vector. Other West Nile vaccine tests also are being pursued, including a DNA vaccine and recombinant subunit vaccines
SARS is an infectious diseases caused by the virus and it is transmitted from person to person through respiratory route and contributing factors are cultivation of wild animals mainly civet cats, through travelling.
Research on the genome of the virus that causes severe acute respiratory syndrome (SARS) has revealed an unusual molecular structure that looks like a promising target for antiviral drugs. A group of scientists determined the three-dimensional shape of this structure, an intricately twisted and folded segment of RNA. These findings suggest that it will help the virus hijack the protein-building system of infected cells.
The virus responsible for causing SARS is a type of RNA virus, meaning that its genetic material is RNA rather which is different from much familiar DNA found in the chromosomes of bacteria to humans. All RNA viruses have high mutation rates compared to DNA viruses, making their genomes highly variable. In HIV, for example, this high rate of mutation contributes to the rapid appearance of drug-resistant strains of the virus. In SARS and related viruses, however, one segment of the RNA genome--known as the s2m RNA--remains virtually unchanged.
The dengue virus which is transmitted through mosquito is spread in almost all tropical and subtropical countries. It is noticed that in 50-100 MN cases found with infection it may cause 20,000 deaths. The virus exists in 4 serotypes and one is more infectious and dangerous than other and infection spreading is fast and it increases to 4 times because of four serotypes. Aedes aegypti, this is primary mosquito vector for transmission of virus. Dengue infection causes hemorrhagic fever and shock syndrome. The symptoms and severity of the infection varies and depends on the serotypes. Normally primates were responsible for transmission of the virus but later on it is decreases and mosquito are found as other main vectors who participates in transmission. These mosquitoes mostly grow in discarded cups, Tiers, waste, trash and waste water storage containers, Drainage etc.
The outcome of the dengue is fatal in more cases and specific vaccine for this infection is not yet found.
Research work is going on the dengue virus a part from the control measures to spread virus there is research undergoing to find the antiviral drugs. By knowing structure and composition of viral protein it is possible to find the vaccine. The aim of this research is several targets, First approach is to inhibit the viral RNA-dependent RNA polymerase which copies the viral genetic material i.e., with nucleoside analogs. Secondly, it is possible to produce specific inhibitors of the viral protease (coded by NS3), which joins viral proteins. At last, to develop entry inhibitors, which stop the virus entering cells, or inhibitors of the 5' capping process; which is required for viral replication.
There are many more emerging infectious agents they are as follows:
Major emerging infectious agents
Year identified Agent
1972 Small round viruses
1983 Human immunodeficiency viruses
1983 Escherichia coli O157
1975 Parvo virus B-19
1983 Helicobacter pylori
1976 Cryptosporidium parvum
1988 Hepatitis E Virus
1977 Ebola virus
1989 Hepatitis C virus
1977 Legionella pneumophila
1992 Vibrio cholerae 0139
1977 Hantaan virus
1992 Bartonella henselae
1977 Campylobacter spp
1980 Human T-lymphotropic virus (HTLV -1)
1997 Influenza A virus (H5N1)
1982 Borrelia burgdorferi
1999 Ehrlichia ewingii
MDR is defined as the multidrug resistance or multiple drug resistance. Multi drug resistance is defined as the condition enabling the organism causing the infection to resist wide variety of drugs administered to eradicate or kill the organism. The multidrug resistant organisms mainly involve pathogenic cells, tumor cells and bacterial cells in the body.
These microorganisms like bacteria and tumor cells employ some methods to get multiple drug resistance.
- Decreased cell wall transfer or increase in thickness of cellwall
- Horizontal gene transfer
- Mutations in the DNA
- Deactivation of antibiotics
- Mechanisms to remove antibiotics like Efflux method
There are many organisms which employ multidrug resistance, thay are called as MDROs. Some of the examples of the organisms are
- Acinetobacter baumannii
- Klebsiella pneumoniae
- Staphylococcus aureus and intermedius
- MRSA (Methicillin resistant Staphylococcus aureus)
- VRE (vancomycin resistant Enterococci)
- ESBL (extended spectrum beta lactamase)- producing Gram negative bacteria
RESEARCH WORK: New Discovery reveals
For the first time, scientists have been able to sketch a detailed chemical picture of how a particular strain of bacteria has modified itself to become resistant to antibiotics. This research is a main step for designing compounds to prevent infections by recently evolved, drug-resistant "superbugs" that are found often in hospitals, as well as in the general population.
Several years ago, genetic studies had revealed that Staphylococcus sciuri -- a non-human bacterial pathogen -- had evolved a new gene called cfr. The protein created by this gene had been found to play a major role in the bacterium's mechanisms of antibiotic resistance. Later, the same gene was found to have crossed over into a strain of Staphylococcus aureus -- very common bacteria that constitutes part of the flora living in the human nose and on skin also and which is now the main cause of various antibiotic-resistant infections. As this gene often is found within a mobile DNA element, it can move easily from a non-human pathogen to other species of bacteria that normally infect humans. The gene, which has been found in Staphylococcus aureus isolates in the United States, Mexico, Brazil, Spain effectively renders the bacteria resistant to seven types of antibiotics. Clearly, bacteria with this gene have a big advantage. However, until now, the whole process by which the protein encoded by that gene exaggerated the genetic makeup of the bacteria was unclear; because they don't have a clear 3D picture of what was going on at the molecular level.
To solve the chemical mystery of how such bacteria overcome so many antibiotics, Scientists investigated how the Cfr protein undertakes a task called methylation -- a method by which enzymes add a small molecular tag to a specific location on a nucleotide -- a molecule that is the structural component of RNA and DNA. When this molecular identifier is added by a protein called RlmN, it facilitates the suitable functioning of the bacterial ribosome -- a massive macromolecular machine that is responsible for making proteins that bacteria need to persist. Many classes of antibiotics bind to the ribosome, disturbing its function and thereby killing the bacteria. The Cfr protein performs an indistinguishable or unique function as the RlmN protein, but it adds the molecular tag at a different place on the same nucleotide. The addition of the tag blocks binding of antibiotics to the ribosome without disrupting its function. What had puzzled scientists is that the locations to which RlmN and Cfr add molecular tags are chemically different from all others to which tags normally are appended, and should be resistant to change by standard chemical methods, What they have revealed here is so exciting because it symbolizes a truly new chemical mechanism for methylation. Now they have a very clear chemical picture of a mysterious mechanism for antibiotic resistance that some bacteria have developed.
TRANSMISSION OF MDRO'S:
MDRO's are mostly transmitted in healthcare facilities. The individuals who gets normally infected by MDRO's are
- Hospitalized patients
- Patients with recent surgery
- Patients mainly in ICU
Mode of transmission of MDRO's is through use of contaminated equipment's like
Urinary catheters, Tracheal tubes etc. Transmission from infected patients to normal patients through body fluids, using contaminated things of patient etc.
PREVENTION AND CONTROL OF MDRO'S:
MDRO's prevention or transmission can be done by following best medical practices and it mainly depends on the patient care with correct clinical practice
- Optimal use of vascular and urinary catheters
- Prevention of respiratory tract infection in ICU patients
- Appropriate diagnosis of infectious etiologies
- antimicrobial selection and utilization
There are few techniques or interventions use of control spread and infection of MDRO's they are:
- Use of antibiotics and antimicrobial agents- extensive use of antibiotics make organisms resistant to drugs and it may not work more so proper care regarding dose of drug should be taken before administering.
- Environmental measures
- Prevention of contact with infected surroundings
- Administrative support and good clinical care
MDRO's infection can be controlled and prevented by maintaining good hand hygiene, washing skin areas at risk for contamination Keeping cuts and burns clean and covered Preventing skin contact or sharing of items with a person with MDRO and the infection.
SOUP UP BUGS:
Soup up bugs is the bugs which cause minor problems in the body like stomach infections, sinus problems, gastric problems.
Soup bugs carry the infection from one person to other and for some bugs there is no treatment. These bugs can present in the environment or also in the body which causes severe problems in the human beings.
Superbug called methicillin-resistant Staphylococcus aureus (MRSA), is a major concern in today's hospitals. This bug is a multidrug resistant. It is reported in almost 35 states in US and seems to cause infection and making cases more fatal.
Even though some antibiotics will work on these super bugs they can't cure them permanently and they are spread all over the country. Improper use of antibiotics made these bugs MDRO's. carbapenem-resistant Klebsiella pneumonia is a new bacteria or bug is popular now a days in many hospitals.
These bugs mostly live in the deeper tissues of the skin and the prevention for transmission of these bugs is to take care of health and prevent transmission from others and contamination by the things infected.
The summary of this independent study is how the old diseases are re-emerging and new diseases are emerging in today's world and what are the factors which mainly contribute for it. Different organisms cause different diseases and this paper gives information on some emerging diseases and the mechanisms undergoing in the organism to withstand the drugs and to cause the infection. This paper also tells about how the infections are transmitted from one person to other, what are the sources for contamination and transmission and also the preventive measures. These organisms are main threat to countries because they can be used for Bio-terrorism. Biotechnology fundamentals course work helped me a lot in understanding the mechanism of the organisms and what recent advances are going on in biotechnology field to overcome the diseases.
Even though we depend on the technology and science, we must encourage the individual study of the nature and local means of control of emerging diseases. However, we also required a more collective approach at the regional, or even better, the global level-this approach is bound up with the support for global action on other fronts in health. The public must be engaged on a more regular basis to consider the saying that public health must be a concern of the public. This advocacy has to use some detailed examples of those matters that disturb the public's health so that emerging diseases are not seen as a threat only on television. The ultimate goal of the research should be such that how infection could be prevented from transmitting to other countries. Disease causing organisms found in one country is not found in other because of so many reasons like environment, vector and the way of living. For example Dengue is found mostly in Asian countries and not in USA because of mosquitoes. It means in Asian countries Disease control department and public should take care of their environment by not allowing scope for mosquito to grow because our ultimate goal in not research but to prevent diseases.