A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY- Patrick Nkemba

A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY COMPILED BY: A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY VIROLOGY 5 COMMON VIRAL INFECTIONS IN HUMANS A RESEARCH PAPER ON VIRAL 5 COMMON VIRAL INFECTIONS A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY CONTENTS INTRODUCTION 1. MUMPS VIRUS 2. RUBELAR VIRUS 3. RABIES VIRUS 4. MEASLES VIRUS 5. COVID-19 VIRUS 5 COMMON VIRAL INFECTIONS - RESEARCH PAPER- BY P.E NKEMBA- MEDICAL STUDENT AT ROCKVIEW UNIVERSITY 1 A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY INTRODUCTION Humans have been living with microorganisms, humans have also been using microorganisms for much longer than they have been able to see them. Historical evidence suggests that humans have had some notion of microbial life since prehistoric times and have used that knowledge to develop foods as well as prevent and treat disease. It should be noted that most microorganisms are harmless to humans and, in fact, many are helpful. They play fundamental roles in ecosystems everywhere on earth, forming the backbone of many food webs. People use them to make biofuels, medicines, and even foods. Without microbes, there would be no bread, cheese, or beer. Our bodies are filled with microbes, and our skin alone is a home to trillions of them. Some of which we can't live without and others can make us sick or even kill us, and such are called pathogens. Pathogens are microorganisms that are capable of causing disease in the host species (man, animals or plants). All the major groups of microorganisms contain species which are pathogenic including viruses, bacteria and fungi. We may be familiar with macropathogens like parasites which includes endoparasites and exoparasites. For instance round worms and lice respectively. Although much more is known today about microbial life than ever before, the vast majority of this invisible world remains unexplored. Microbiologists continue to identify new ways that microbes benefit and threaten humans. However, this research is more focused on viruses and specifically Mumps Virus, Rubellar Virus, Rabies Virus, Measles Virus and Covid 19 virus. A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses can infect all types of life forms, from animals and plants to microorganisms, including bacteria and archaea. In order to survive and reproduce, viruses must infect a cellular host, which makes them obligate intracellular parasites, they are infectious agents which are typically of a nucleic acid molecule in a protein coat. They lack the capacity to survive and reproduce without the host. Lets now take a quick walk through the world of microbiology and check on an interesting discipline and branch of microbiology called Virology. Virology is the study of viruses. In this direction we are going to narrow our work more by just looking at 5 viral infections which are; Mumps, Rubelar, Rabies, Measles and Covid 19. In each we will look at:           Microbiology Mode of transmission Epidemiology Pathogenesis Clinical presentation Diagnosis Treatment prevention Complications Prognosis 5 COMMON VIRAL INFECTIONS - RESEARCH PAPER- BY P.E NKEMBA- MEDICAL STUDENT AT ROCKVIEW UNIVERSITY 2 A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY 1. MUMPS Microbiology Mode of transmission Epidemiology Pathogenesis Clinical presentation Diagnosis Treatment prevention Complications Prognosis MUMPS Mumps is a viral illness caused by a paramyxovirus, a member of the Rubulavirus family. Initial symptoms are non-specific and include fever, headache, malaise, muscle pain, and loss of appetite. These symptoms are usually followed by painful swelling of the parotid glands, called parotitis, which is the most common symptom of infection. MICROBIOLOGY It is an enveloped, single-stranded RNA virus in the paramyxovirus family. Mumps virus is related to parainfluenza and Newcastle disease viruses, and antibodies to these viruses may cross-react with mumps virus EPIDEMIOLOGY Mumps historically has been a highly prevalent disease, commonly occurring in outbreaks in densely crowded spaces. In the absence of vaccination, infection normally occurs in childhood, most frequently at the ages of 5–9. mumps virus, an RNA virus in the family Paramyxoviridae. MODE OF TRANSMITTION The virus is primarily transmitted by respiratory secretions such as droplets and saliva, as well as via direct contact with an infected person. Mumps is highly contagious and spreads easily in densely populated settings. Transmission can occur from one week before the onset of symptoms to eight days after. PATHOPHYSIOLOGY During infection, the virus first infects the upper respiratory tract. From there, it spreads to the salivary glands and lymph nodes. Infection of the lymph nodes leads to presence of the virus in blood, which spreads the virus throughout the body. Mumps infection is usually self-limiting, coming to an end as the immune system clears the infection. CLINICAL PRESENTATION Symptoms typically occur 16 to 18 days after exposure to the virus and resolve within two weeks. About one third of infections are asymptomatic. Complications include deafness and a wide range of inflammatory conditions, of which inflammation of the testes, breasts, ovaries, pancreas, meninges, and brain are the most common. Testicular inflammation may result in reduced fertility and, rarely, sterility. 5 COMMON VIRAL INFECTIONS - RESEARCH PAPER- BY P.E NKEMBA- MEDICAL STUDENT AT ROCKVIEW UNIVERSITY 3 A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY PHASES Over the course of the disease, three distinct phases are recognized: Prodromal, early acute, and established acute.  The prodromal phase- typically has non-specific, mild symptoms such as a low-grade fever, headache, malaise, muscle pain, loss of appetite, and sore throat.  In the early acute phase, as the mumps virus spreads throughout the body, systemic symptoms emerge. Most commonly, parotitis occurs during this time period.  During the established acute phase, orchitis, meningitis, and encephalitis may occur, and these conditions are responsible for the bulk of mumps morbidity. DIAGNOSIS In places where mumps is common, it can be diagnosed based on clinical presentation. In places where mumps is less common, however, laboratory diagnosis using antibody testing, viral cultures, or real-time reverse transcription polymerase chain reaction may be needed. TREATMENT AND PREVENTION There is no specific treatment for mumps, so treatment is supportive in nature and includes bed rest and pain relief. Infection can be prevented with vaccination, either via an individual mumps vaccine or through combination vaccines such as the MMR vaccine, which also protects against measles and rubella. The spread of the disease can also be prevented by isolating infected individuals PROGNOSIS AND COMPLICATIONS Prognosis is usually excellent with a full recovery as death and long-term complications are rare. Symptoms and complications are more common in males and more severe in adolescents and adults. During the established acute phase, orchitis, meningitis, and encephalitis may occur, and these conditions are responsible for the bulk of mumps morbidity. The parotid glands are salivary glands situated on the sides of the mouth in front of the ears. Inflammation of them, called parotitis, is the most common mumps symptom and occurs in about 90% of symptomatic cases and 60–70% of total infections. During mumps parotitis, usually both the left and right parotid glands experience painful swelling, with unilateral swelling in a small percentage of cases. Parotitis occurs 2–3 weeks after exposure to the virus, within two days of developing symptoms, and usually lasts 2–3 days, but it may last as long as a week or longer. In 90% of parotitis cases, swelling on one side is delayed rather than both sides swelling in unison. The parotid duct, which is the opening that provides saliva from the parotid glands to the mouth, may become red, swollen, and filled with fluid. Parotitis is usually preceded by local tenderness and occasionally earache. Other salivary glands, namely the submaxillary, submandibular, and sublingual glands, may also swell. Inflammation of these glands is rarely the only symptom. 5 COMMON VIRAL INFECTIONS - RESEARCH PAPER- BY P.E NKEMBA- MEDICAL STUDENT AT ROCKVIEW UNIVERSITY 4 A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY Complications Outside of the salivary glands, Inflammation of the testes, called orchitis, is the most common symptom infection. Pain, swelling, and warmness of a testis appear usually 1–2 weeks after the onset of parotitis but can occur up to six weeks later. During mumps orchitis, the scrotum is tender and inflamed. It occurs in 10–40% of pubertal and postpubertal males who contract mumps. Usually, mumps orchitis affects only one testis but in 10–30% of cases usually both are affected. Mumps orchitis is accompanied by inflammation of the epididymis, called epididymitis, about 85% of the time, typically occurring before orchitis. The onsent of mumps orchitis is associated with a high-grade fever, vomiting, headache, and malaise. In prepubertal males, orchitis is rare as symptoms are usually restricted to parotitis. Mastitis A variety of other inflammatory conditions may also occur as a result of mumps virus infection, including Mastitis, inflammation of the breasts, in up to about 30% of post-pubertal women. Oophoritis Oophoritis, inflammation of an ovary, in 5–10% of post-pubertal women, which usually presents as pelvic pain Aseptic meningitis Aseptic meningitis, inflammation of the meninges, in 5–10% of cases[15] and 4–6% of those with parotitis, typically occurring 4–10 days after the onset of symptoms. Mumps meningitis can also occur up to one week before parotitis as well as in the absence of parotitis. It is commonly accompanied by fever, headache, vomiting, and neck stiffness. Pancreatitis Pancreatitis, inflammation of the pancreas, in about 4% of cases, which causes severe pain and tenderness in the upper abdomen below the ribs Encephalitis Encephalitis, inflammation of the brain, in less than 0.5% of cases. People who experience mumps encephalitis typically experience a fever, altered consciousness, seizures, and weakness. Like meningitis, mumps encephalitis can occur in the absence of parotitis. Meningoencephalitis Meningoencephalitis, inflammation of the brain and its surrounding membranes. Mumps meningoencephalitis is commonly accompanied by fever 97% of the time, vomiting 94% of the time, and headache 88.8% of the time. Nephritis Nephritis, inflammation of the kidneys, which is rare because kidney involvement in mumps is usually benign but leads to presence of the virus in urine. 5 COMMON VIRAL INFECTIONS - RESEARCH PAPER- BY P.E NKEMBA- MEDICAL STUDENT AT ROCKVIEW UNIVERSITY 5 A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY Arthritis Inflammation of the joints (arthritis), which may affect at least five joints (polyarthritis), Polyneuritis Multiple nerves in the peripheral nervous system (polyneuritis), pneumonia, gallblader without gallstones (acalculous cholecystitis), cornea and uveal tract (keratouveitis), thyroids (thyroiditis), liver (hepatitis), retina (retinitis), and corneal endothelium (corneal endothelitis), all of which are rare.] Recurrent sialadenitis, inflammation of the salivary glands, which is frequent. Deafness A relatively common complication is deafness, which occurs in about 4% of cases. Mumps deafness is often accompanied by vestibular symptoms such as vertigo and repetitive, uncontrolled eye movements. Based on electrocardiographic abnormalities in the infected, MuV also likely infects cardiac tissue, but this is usually asymptomatic. Rarely, myocarditis and pericarditis can occur. Hydrocephalus Fluid buildup in the brain, called hydrocephalus, has also been observed. In the first trimester of pregnancy, mumps may increase the risk of miscarriage. Otherwise, mumps is not associated with birth defects. Other rare complications of infection include: paralysis, seizures, cranial nerve palsies, cerebellar ataxia, transverse myelitis, ascending polyradiculitis, a polio-like disease, arthropathy, autoimmune hemolytic anemia. 5 COMMON VIRAL INFECTIONS - RESEARCH PAPER- BY P.E NKEMBA- MEDICAL STUDENT AT ROCKVIEW UNIVERSITY 6 A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY 2. RUBELAR VIRUS Microbiology Mode of transmission Epidemiology Pathogenesis Clinical presentation Diagnosis Treatment prevention Complications Prognosis RUBELAR VIRUS Rubella, also known as German measles or three-day measles, is an infection caused by the rubella virus also called Togavirus. MICROBIOLOGY Togavirus belongs to the family of viruses called Togaviridae. The virus is enveloped, Icosahedral, positive-sense single stranded RNA genome. MODE OF TRANSMISSION Rubella is usually spread from one person to the next through the air via coughs or respiratory droplets of people who are infected. In pregnancy, the virus can cross the placenta and infect the fetus, leading to Congenital Rubella Syndrome. Babies with CRS may spread the virus for more than a year. Only humans are infected by Togavirus, Insects do not spread the disease. EPIDEMIOLOGY Rubella occurs worldwide. The virus tends to peak during the spring in countries with temperate climates. Before the vaccine against rubella was introduced in 1969, widespread outbreaks usually occurred every 6–9 years in the United States and 3– 5 years in Europe, mostly affecting children in the 5-9 year old age group. PATHOGENESIS  The virus enters an individual via the Respiratory tract.  It first invade and replicate in the nasal pharynx of the Respiratory tract.  Virus continues to replicate and later invade lymph nodes.  This is followed by a viremia, spreading viruses to targeted organs, 5- 7 days after exposure.  Later, the infection is established in the skin and other body tissues, followed by the development of Forchheimer’s spot.  Rashes develop, cough, conjunctivitis, anorexia, and many other associated signs and symptoms. CLINICAL PRESENTATION A fever, sore throat, and fatigue may also occur, Anoroxia (Loss of Appetite), Pharyngitis (Sore throat), Headache, Dry Cough, Muscle pain (Myalgia), Malaise, Maculopapular Rash, Lymphadenopathy, Conjunctivitis, Rhinitis (Runny nose) Mild fever, Joint pain is common in adults. 5 COMMON VIRAL INFECTIONS - RESEARCH PAPER- BY P.E NKEMBA- MEDICAL STUDENT AT ROCKVIEW UNIVERSITY 7 A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY DIAGNOSIS  Physical Examination Examine the Rash Forchheimer’s spot.  Testing the blood for antibodies may also be useful and it can help us to verify immunity (Serologic test) or Detection of IgM antibodies in a serum sample, (few days after rash onset).  Diagnosis is confirmed by finding the virus in the blood, throat, or urine (Virus Culture)  Reverse Transcriptase – Polymerase Chain Reaction (RT-PCR) Detect presence of viral RNA  Full Blood Count (FBC) TREATMENT There is no specific treatment for rubella; however, management is a matter of responding to symptoms to diminish discomfort. Treatment of newborn babies is focused on management of the complications. Congenital heart defects and cataracts can be corrected by direct surgery. Management for ocular congenital rubella syndrome (CRS) is similar to that for age-related macular degeneration, including counseling, regular monitoring, and the provision of low vision devices, if required. PREVENTION Rubella is preventable with the rubella vaccine with a single dose being more than 95% effective. Often it is given in combination with the measles vaccine and mumps vaccine, known as the MMR vaccine. It is recommended that all susceptible non-pregnant women of childbearing age should be offered rubella vaccination. Due to concerns about possible teratogenicity, use of MMR vaccine is not recommended during pregnancy. Instead, susceptible pregnant women should be vaccinated as soon as possible in the postpartum period. In susceptible people passive immunization, in the form of Polyclonal immunoglobulins appears effective up to the fifth day post-exposure. COMPLICATIONS Complications may include bleeding problems, testicular swelling, encephalitis, and inflammation of nerves. Infection during early pregnancy may result in a miscarriage or a child born with congenital rubella syndrome (CRS). PROGNOSIS Rubella infection of children and adults is usually mild, self-limiting and often asymptomatic. Once recovered, people are immune to future infections. The prognosis in children born with CRS is poor. Symptoms of CRS manifest as problems with the eyes such as cataracts, deafness, as well as affecting the heart and brain. Problems are rare after the 20th week of pregnancy. 5 COMMON VIRAL INFECTIONS - RESEARCH PAPER- BY P.E NKEMBA- MEDICAL STUDENT AT ROCKVIEW UNIVERSITY 8 A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY 3. RABIES VIRUS Microbiology Mode of transmission Epidemiology Pathogenesis Clinical presentation Diagnosis Treatment prevention Complications Prognosis Rabies virus, scientific name lyssavirus, is a neurotropic virus that causes rabies in humans and animals. Rabies is a viral infection that mainly spreads through a bite from an infected animal. MICROBIOLOGY  Rabies lyssavirus is a member of the Lyssavirus genus of the Rhabdoviridae family.  Rhabdoviruses have helical symmetry, so their infectious particles are approximately cylindrical in shape.  These viruses are enveloped and have a single stranded RNA genome with negative-sense.  The genetic information is packaged as a ribonucleoprotein complex in which RNA is tightly bound by the viral nucleoprotein.  The RNA genome of the virus encodes five genes whose order is highly conserved.  These genes code for: nucleoprotein (N), phosphoprotein (P), matrix protein (M), glycoprotein (G) and the viral RNA polymerase (L) MODE OF TRANSMISSION  A bite from an infected dog, or generally animal in a geographical area where rabies occurs should seek treatment at once.  Rabies can develop if a person receives a bite from an infected animal, or if saliva from an infected animal gets into an open wound or through a mucous membrane, such as the eyes or mouth. -It cannot pass through unbroken skin. PATHOGENESIS From the wound of entry, Rabies lyssavirus travels quickly along the neural pathways of the peripheral nervous system. The retrograde axonal transport of Rabies lyssavirus to the central nervous system (CNS) is the key step of pathogenesis during natural infection. The exact molecular mechanism 5 COMMON VIRAL INFECTIONS - RESEARCH PAPER- BY P.E NKEMBA- MEDICAL STUDENT AT ROCKVIEW UNIVERSITY 9 A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY of this transport is unknown although binding of the P-protein from Rabies lyssavirus to the dynein light chain protein DYNLL1 has been shown. P also acts as an interferon antagonist, thus decreasing the immune response of the host. From the CNS, the virus further spreads to other organs like the salivary glands located in the tissues of the mouth and cheeks receive high concentrations of the virus, thus allowing it to be further transmitted due to projectile salivation. Once inside the nervous system, the virus produces acute inflammation of the brain. Coma and death soon follow. There are two types of rabies. i) Furious, or encephalitic rabies: This occurs in 80 percent of human cases. The person is more likely to experience hyperactivity and hydrophobia. ii) Paralytic or “dumb” rabies: Paralysis is a dominant symptom. CLINICAL PRESENTATION The first symptoms of rabies may be very similar to those of the flu including general weakness or discomfort, fever, or headache. These symptoms may last for days. There may be also discomfort or a prickling or itching sensation at the site of bite, progressing within days to symptoms of cerebral dysfunction, anxiety, confusion, agitation. As the disease progresses, the person may experience delirium, abnormal behavior, hallucinations, and insomnia and death. Rabies lyssavirus may also be inactive in its host's body and become active after a long period of time. Signs are well understood when associted with phases of disease progression as follows: Incubation- 5 days to 12weeks  This is the time before symptoms appear. It usually lasts from 3 to 12weeks, but it can take as little as 5 days or more than 2 years.  The closer the bite is to the brain, the sooner the effects are likely to appear.  By the time symptoms appear, rabies is usually fatal. Anyone who may have been exposed to the virus should seek medical help at once, without waiting for symptoms. Prodrome- 2 to 10 days During the prodrome stage of rabies, a person may experience: Early symptoms, include:  headache  anxiety  feeling generally unwell  sore throat and a cough  fever- a fever of (38 degrees Celsius) or above  nausea and vomiting  discomfort may occur at the site of the bite These can last from 2 to 10 days, and they worsen over time. 5 COMMON VIRAL INFECTIONS - RESEARCH PAPER- BY P.E NKEMBA- MEDICAL STUDENT AT ROCKVIEW UNIVERSITY 10 A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY Neurologic symptoms, include:  confusion and aggression.  partial paralysis, involuntary muscle twitching, and rigid neck muscles.  Convulsions.  hyperventilation and difficulty breathing.  hypersalivation or producing a lot of saliva, and possibly frothing at the mouth.  fear of water, or hydrophobia, due to difficulties in swallowing.  hallucinations, nightmares, and insomnia.  priapism, or permanent erection, in males. Acute neurologic period Coma- If the person enters a coma, death will occur within a matter of hours, unless they are attached to a ventilator. It is very rare for a person to recover at this late stage, Unless with the divine intervention. DIAGNOSIS  At the time of a bite, there is usually no way to tell for sure whether an animal has passed on an infection or not.  Lab tests may show antibodies, but these may not appear until later in the development of the disease. The virus may be isolated from saliva or through a skin biopsy. However, by the time a diagnosis is confirmed, it may be too late to take action.  For this reason, the patient will normally start a course of prophylactic treatment at once, without waiting for a confirmed diagnosis.  If a person develops symptoms of viral encephalitis following an animal bite, they should be treated as if they may have rabies. TREATMENT AND PREVENTION Once rabies is established their is nothing that could be done except intensive care unit. Treatment If a person is bitten or scratched by an animal that may have rabies, or if the animal licks an open wound, the individual should immediately wash any bites and scratches for 15 minutes with soapy water, povidone Iodine, or detergent. This might minimize the number of viral particles. After exposure and before symptoms begin, a series of shots can prevent the virus from thriving. This is usually effective. A fast-acting dose of rabies immune globulin: Delivered as soon as possible, close to the bite wound, this can prevent the virus from infecting the individual. Post-exposure prophylaxis: essential components post-exposure prophylaxis are local treatment of wounds, active and passive immunization. Prevention Pre-exposure prophylaxis: For persons at high risk of infection, such as vets, laboratory workers, animal handlers and wildlife officers should be 5 COMMON VIRAL INFECTIONS - RESEARCH PAPER- BY P.E NKEMBA- MEDICAL STUDENT AT ROCKVIEW UNIVERSITY 11 A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY considered for pre-exposure prophylaxis by active immunisation with the cell culture vaccine. Rabies is a serious disease, but individuals and governments can take action to control and prevent it, and, in some cases, wipe it out completely. Strategies include:  Regular anti-rabies vaccinations for all pets and domestic animals  Bans or restrictions on the import of animals from some countries  Widespread vaccinations of humans in some areas. COMPLICATIONS  confusion and aggression.  partial paralysis, involuntary muscle twitching, and rigid neck muscles.  Convulsions.  hyperventilation and difficulty breathing.  hypersalivation or producing a lot of saliva, and possibly frothing at the mouth.  fear of water, or hydrophobia, due to difficulties in swallowing.  hallucinations, nightmares, and insomnia.  priapism, or permanent erection, in males. PROGNOSIS A good prognosis exists if a bite is treated before the beginning of the neurological symptoms of the prodromal phase, therefore we shouldn’t wait for the diagnosis to be confirmed because by that time it may be too late to take action. Coma- If the person enters a coma, death will occur within a matter of hours, unless they are attached to a ventilator. It is very rare for a person to recover at this late stage, Unless with the divine intervention. 5 COMMON VIRAL INFECTIONS - RESEARCH PAPER- BY P.E NKEMBA- MEDICAL STUDENT AT ROCKVIEW UNIVERSITY 12 A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY 4. MEASLES VIRUS Microbiology Mode of transmission Epidemiology Pathogenesis Clinical presentation Diagnosis Treatment prevention Prognosis Complications MEASLES VIRUS Measles is a highly contagious infectious viral disease caused by measles virus or Rubeola virus. It is characterized by a late onset of a red-flat rash and is accompanied by High fever. MICROBIOLOGY Measles virus (Rubeola) belongs to a genus morbillivirus of the family, “Paramyxovirus.” It is an enveloped virus, non-segmented and single stranded negative sense RNA virus. Its genome encodes at least six structural protein. MODE OF TRANSMISSION Measles is an airborne disease which spreads through coughs and sneezes of infected people. It may also be spread through direct contact with mouth or nasal secretion or respiratory droplets. The virus remains active and contagious in the air or on infected surface for up to two (2) hours. PATHOGENESIS  Measles virus first infects and replicates in the epithelial cells of the respiratory tract.  The virus then spread to the immediate lymph nodes and to the lymphoid organs.  Destruction of the lymphoid tissues leads to a profound leucopenia (low levels of white Blood cells).  Primary viremia develops and is responsible for the spread of virus throughout the respiratory system and the Reticuloendothelial system.  Secondary viremia follows were the virus is further spread to involve the skin, viscera, kidney and bladder.  Primary viremia develops and is responsible for the spread of virus throughout the respiratory system and the Reticuloendothelial system.  Secondary viremia follows were the virus is further spread to involve the skin, viscera, kidney and bladder. 5 COMMON VIRAL INFECTIONS - RESEARCH PAPER- BY P.E NKEMBA- MEDICAL STUDENT AT ROCKVIEW UNIVERSITY 13 A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY CLINICAL PRESENTATION  Fever  Rhinitis (Runny nose) coryza  Conjunctivitis  Dry cough  Pharyngitis  Anorexia  Koplik’s spot  Diarrhea The development of measles is best understood when separated into phases. And measles has four phases; INCUBATION PERIOD The incubation period is 8-10 days after exposed to the virus. During this period, patient is asymptomatic. PRODROMAL PHASE Lasts 2-4 days and is marked by fever (39-40 degrees C). It is accompanied by Malaise, Coryza, Conjunctivitis and Pharyngitis. Koplik’s spot develop on the buccal mucosa during this phase, days before the rash appears. NB: Koplik’s spots seen inside the mouth are pathognomic (diagnostic) for measles, but are temporary and therefore rarely seen.      EXANTHEM PHASE The phase begins after prodromal phase; two (2) weeks after exposure. The Erythematous Maculopapular rash first appears behind the ears and on the neck. The rash progresses to cover face, trunk, arms, legs and feet within 73 hours. The fever peaks on the 2nd or 3rd day of the rash. The Rash usually begins to clear in the same order of progression as it appeared. This happens the 3rd or 4th day after onset. 5 COMMON VIRAL INFECTIONS - RESEARCH PAPER- BY P.E NKEMBA- MEDICAL STUDENT AT ROCKVIEW UNIVERSITY 14 A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY   RECONVALENCE PHASE After 10-12 days, resolution of the rash. May be followed by desquamation leaving transient hyper pigmented areas. DIAGNOSIS Typically, clinical diagnosis begins with the onset of fever and malaise about 10 days after exposure to the measles virus, followed by the emergence of cough, coryza, and conjunctivitis that worsen in severity over 4 days of appearing. Observation of Koplik's spots is also diagnostic. Other possible condition that can result in these symptoms include parvovirus, dengue fever, Kawasaki disease, and scarlet fever. Laboratory confirmation is however strongly recommended. Laboratory testing Laboratory diagnosis of measles can be done with confirmation of positive measles IgM antibodies or detection of measles virus RNA from throat, nasal or urine specimen by using the reverse transcription polymerase chain reaction assay. This method is particularly useful to confirm cases when the IgM antibodies results are inconclusive TREATMENT AND PREVENTION There is no treatment for established measles infection. We on treat signs and symptoms also give some anti-pyretic agents. Vitamin A markedly reduce rate of morbidity and Mortality. Hydrate if dehydration is present and give Anti-biotics in suspected individuals with bacterial infection then bed rest is all they will need from here. The only way to prevent measles is by vaccinating people with high risk factors All Children of the age 12 to 15 months should be given the first dose of the vaccine, and the second dose at 4 to 6 years of age. One of the vaccines you can give is Measles, Mumps and Rubella (MMR). The dosage for MMR and is 0.5mL, administered by the subcutaneous route. Make sure pregnant women women are vaccinated as well. PROGNOSIS Most people survive measles, though in some cases complications occurs. However, It should be noted that about 1 in 4 individuals will be hospitalised and 1-2 in 1000 will die. NOTE:Complications are more likely to occur in children under 5yrs and adults over 20yrs. COMPLICATIONS  Acute Laryngotracheobronchitis  Giant-Cell Pneumonitis  Secondary Bacterial Infection (e.g.; Otitis media and Bronchopneumonia)  Central Nervous system (like Encephalomyelitis).  Subacute Sclerosing panencephalititis (SSPE) which is very rare. 5 COMMON VIRAL INFECTIONS - RESEARCH PAPER- BY P.E NKEMBA- MEDICAL STUDENT AT ROCKVIEW UNIVERSITY 15 A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY 5. COVID 19 Microbiology Mode of transmission Epidemiology Pathogenesis Clinical presentation Diagnosis Treatment prevention Complications and Prognosis COVID 19 Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has resulted in more than 1.45 million of deaths worldwide.Coronaviruses are a group of related RNA viruses that cause diseases in humans and birds, they cause respiratory tract infections that can range from mild to lethal. MICROBIOLOGY Coronaviruses constitute the subfamily Orthocoronavirinae, in the family Coronaviridae, order Nidovirales and realm Riboviria. They are enveloped viruses with a positive-sense single-stranded RNA genome and a nucleocapsid of helical symmetry. EPIDEMIOLOGY SARS-CoV-2 prevalence estimates ranged from 1·6% to 45·1%. To our knowledge, this is the first population-based SARS-CoV-2 prevalence study done in Africa. The findings showed high prevalence of rt-PCR-positive SARS-CoV-2 infections in Zambia in July, 2020, which was a period of community transmission in the country.As of 9th Mar 2021. PATHOGENESIS Following viral transmission, SARS-CoV-2 attaches to the surface of the epithelial membrane of the oral cavity, the mucosal membranes of the conjunctiva or the otic canal. ACE 2 protein, which is highly expressed on multiple human cells including type II alveolar cells (AT2), oral, esophageal, ileal epithelial cells, myocardial cells, proximal tubule cells of the kidneys as well as urothelial cells of the bladder is believed to mediate the internalization of SARS-CoV2. The spike (S) protein of SARS-CoV2 is cleaved by a cellular enzyme named furin at the S1/S2 site. This cleavage is essential for viral entry to the lung cells. The activated S protein is primed by the TMPRSS2 and finally attaches ACE 2 receptors to enter the host cells. 5 COMMON VIRAL INFECTIONS - RESEARCH PAPER- BY P.E NKEMBA- MEDICAL STUDENT AT ROCKVIEW UNIVERSITY 16 A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY The genetic sequence of SARS-CoV-2 is homologous with the SARS-CoV, and the structure of (S) protein of these viruses is highly similar. They both use the same receptor to enter the host cell; however, SARS-CoV-2 binds ACE 2 receptors with tenfold higher affinity.The severity of COVID-19 is positively correlated to the level of inflammatory cytokines such as interleukins (IL-2, IL-6, IL-7, IL-10), GCSF, IP-10, MCP-1, MIP-1A and TNF-α. In patients with severe disease, a significant reduction in lymphocyte count is observed. Flow cytometric analysis of severe COVID-19 patients demonstrates a remarkable reduction of lymphocytic T Cells (CD4+ and CD8+) and natural killer (NK) cell. CLINICAL PRESENTATION The common clinical features of COVID-19 pneumonia in adults include fever, dry cough, sore throat, headache, fatigue, myalgia and breathlessness DIAGNOSIS Diagnosis of coronavirus disease 2019 (COVID-19) requires detection of SARSCoV-2 RNA in samples from the nose (nasopharyngeal swab), throat (throat swab) or saliva. The samples are then sent to a lab for reverse transcription polymerase chain reaction (RT-PCR). TREATMEN PREVENTION There is no cure for COVID-19, however, a number of vaccines using different methods have been developed against human coronavirus SARS-CoV-2. Antiviral targets against human coronaviruses have also been identified such as viral proteases, polymerases, and entry proteins. Drugs are in development which target these proteins and the different steps of viral replication. COMPLICATIONS AND PROGNOSIS For critically ill patients with COVID-19, the prognosis is poor with mortality ranging from 25 to 50 percent that is largely driven by severe ARDS. However, death can occur from several other conditions including cardiac arrythmia, cardiac arrest, and pulmonary embolism. Respiratory system involvement The predominant manifestation of COVID-19 is the involvement of the respiratory system presenting as interstitial and alveolar pneumonia. Thin slice chest computerized tomography (CT) is useful for early detection of COVID-19 pneumonia. Cardiovascular involvement Hypertension, diabetes, heart failure and coronary artery disease are the most particular comorbidities that have been identified in COVID-19 patients. Imbalanced activation of the ACE 2/angiotensin (1–7) pathway is associated with a proinflammatory state and is assumed to cause more severe disease in patients with cardiovascular comorbidities. Kidney involvement Acute kidney injury (AKI) is one of the major contributing factors of COVID-19-related death [72]. Similar to SARS-CoV and MERS, the kidneys are potential targets for COVID-19. Hematologic involvement, Coagulopathy, Electrolyte imbalance, Endocrine involvement. 5 COMMON VIRAL INFECTIONS - RESEARCH PAPER- BY P.E NKEMBA- MEDICAL STUDENT AT ROCKVIEW UNIVERSITY 17 A QUICK WALK THROUGH THE WORLD OF MICROBIOLOGY THANkS So MUcH for THE TIME SpENT IN THIS grEAT joUrNEy Further reading REFERENCES 1. Subhash.C. P, 2012. Microbiology and Immunology 2nded. EIH unit Ltd, Manesar. 2. C.J Clegg, 2007. Biology for IB diploma. Hodder Education, part of Hachatte Livre UK, 338 Euston Road. London NW1 3BH. p.553 3. Openstax, 2016. Microbiology. Rice University, 6100 main Street MS-375. Houston, Taxas 77005. p.239 4. Dennis.J, Jennifer.G, Mary.J and Richard.F, 2014. Cambridge International AS and A level biology course book 4thed. University printing house, Cambridge CB2 8BS, United kingdom. p.440 5. http://www.emro.who.int.com Written by: PATRICK NKEMBA 5 COMMON VIRAL INFECTIONS - RESEARCH PAPER- BY P.E NKEMBA- MEDICAL STUDENT AT ROCKVIEW UNIVERSITY 18