virus pathogenicity, symptoms and disease

Question 1

Virus pathogenicity

Answer 1

the ability of a virus to cause disease

Not all viruses are pathogenic, some are pathogenic under certain conditions.

Question 2

Viral disease

Answer 2

a sum of the effects on the host arising form virus replication and the immune response

Question 3

subclinical or asymptomatic infections

Answer 3

Infections that do not result in disease are known as subclinical or asymtomatic

Symptoms arising from virus infection may vary from asymtomatic, mild, moderate and acute, depending on a number of factors such as virus virulence, viral dose, host immune status, etc.

Question 4

Adenoviruses

Answer 4

• They are medium-sized (90-100 nm), non-enveloped icosohedral viruses with double-stranded DNA.
• More than 50 types of immunologically distinct adenoviruses can cause infections in humans.
• Adenoviruses are relatively resistant to common disinfectants and can be detected on surfaces, such as doorknobs, objects, and water of swimming pools and small lakes

Question 5

Adenovirus transmission

Answer 5

• Adenoviruses are usually transmitted from infected people to others through:
• close personal contact such as touching or shaking hands
• the air by coughing and sneezing
• touching objects or surfaces with adenoviruses on them then touching your mouth, nose, or eyes.

Question 6

Adenovirus symptoms

Answer 6

Adenoviruses symptoms are:
• common cold or flu-like symptoms
• fever
• sore throat
• acute bronchitis (inflammation of the airways of the lungs, sometimes called a “chest cold”)
• pneumonia (infection of the lungs)
• pink eye (conjunctivitis)
• acute gastroenteritis (inflammation of the stomach or intestines causing diarrhea, vomiting, nausea
and stomach pain).
• less commonly, neurological disease.
• People with weakened immune systems are at high risk for developing severe illness caused by adenovirus infection.
• Some people infected with adenoviruses, especially those who have weakened immune systems, can have ongoing infections in their tonsils, adenoids, and intestines that do not cause symptoms. They can shed the virus for weeks or longer.
• Prevention of adenoviruses is through vaccine administration

Question 7

Varicella (chickenpox)

Answer 7

• Varicella, commonly called chickenpox is an acute infectious disease.
• It is caused by varicella-zoster virus (VZV), which is a DNA virus that is a member of the family
herpesviridae

Question 8

Varicella (chickenpox)

Transmission

Answer 8

Transmission can occur through contact, inhalation of aerosols from vesicular fluid from skin lesions

Question 9

Varicella (chickenpox)

disease and infection

Answer 9

• Disease: After the primary infection, VZV stays in the body (in the sensory nerve ganglia) as a latent
infection

• Primary infection with VZV causes varicella (chickenpox).
• Reactivation of latent infection causes herpes zoster (shingles or painful rash)

Question 10

Varicella (chickenpox)

symptoms

Answer 10

• Primary infection with VZV causes varicella (chickenpox).
• Reactivation of latent infection causes herpes zoster (shingles or painful rash).
• The rash is generalized and pruritic (itchy).
• It progresses rapidly from macular to papular to vesicular lesions before crusting.
• Lesions are typically present in all stages of development at the same time.
• The rash usually appears first on the chest, back, and face, then spreads over the entire body.
• The lesions are usually most concentrated on the chest and back.
• Symptoms typically last 4 to 7 days.

Question 11

Varicella (chickenpox)

incubation period

Answer 11

• Incubation Period
• The average incubation period for varicella is 14 to 16 days after exposure to a varicella or a herpes zoster rash, with a
range of 10 to 21 days.
• Early symptoms of mild fever and malaise may occur 1 to 2 days before rash onset, particularly in adults. In children, the
rash is often the first sign of disease

Question 12

Varicella (chickenpox)

complications

Answer 12

• Complications
• The most common complications from varicella are:
• In children: Bacterial infections of the skin and soft tissues
• In adults: Pneumonia (lung inflammation, pus filling the air sacs)
• Severe complications caused by the virus include cerebellar ataxia, encephalitis, viral pneumonia, and hemorrhagic
conditions. Other severe complications are due to bacterial infections and include:
• Septicemia (Blood poisoning by bacteria)
• Toxic shock syndrome (condition due accumulation of pathogenic toxins)
• Necrotizing fasciitis (rare bacteria infection)
• Osteomyelitis
• Bacterial pneumonia
• Septic arthriti

Question 13

Herpes zoster virus

Answer 13

Herpes zoster, also known as shingles (painful rash), caused by the reactivation of
the varicella-zoster virus (VZV), the same virus that causes varicella (chickenpox)

Question 14

Herpes zoster virus

symptoms

Answer 14

Primary infection with VZV causes varicella. Once the illness resolves, the virus
remains latent in the dorsal root ganglia (neurons). VZV can be reactive later in a
person’s life and cause a painful, maculopapular rash called herpes zoster.
• The rash is usually painful, itchy, or tingly. These symptoms may precede rash
onset by several days. Some people may also have headache, photophobia
(sensitivity to bright light), and malaise in the prodromal phase.
• The rash develops into clusters of vesicles. New vesicles continue to form over
three to five days and progressively dry and crust over. They usually heal in two to
four weeks. There may be permanent pigmentation changes and scarring on the
skin.

Question 15

Herpes zoster virus

vaccine

Answer 15

• Vaccine: Recombinant zoster vaccine (RZV, Shingrix) is the recommended vaccine
to prevent shingles and its complications.

Question 16

Conjunctivitis (Pink eye)

Answer 16

People often refer to conjunctivitis “pink eye” because it can cause the white of the eye to take on a pink
or red color.
• Symptoms of pink eye can vary but typically include redness or swelling of the white of the eye

Question 17

Conjunctivitis (Pink eye)

viral causes

Answer 17

Cause: An array of viruses can cause viral conjunctivitis, with adenoviruses being one of the most common
causes:
• Adenoviruses
• Rubella virus
• Rubeola (measles) virus
• Herpesviruses, including
• Herpes simplex virus
• Varicella-zoster virus, which also causes chickenpox and shingles
• Epstein-Barr virus, which also causes infectious mononucleosis (mono)
• Picornaviruses, such as coxsackievirus A24 and enterovirus 70 (which has caused outbreaks in other
countries

Question 18

Conjunctivitis (Pink eye)

transmission

Answer 18

• Viral conjunctivitis is highly contagious. Most viruses that cause conjunctivitis spread through hand-to-eye contact by hands or objects that are
contaminated with the infectious virus.

• Having contact with infectious tears, eye discharge, fecal matter, or respiratory discharges can contaminate hands. Viral conjunctivitis can also
spread by large respiratory tract droplets. As viral conjunctivitis can be highly contagious, infected individuals should be counseled to prevent
transmission e.g., washing hands frequently, using separate towels, and avoiding close contact with others during the period of contagion.

• Most cases of acute, infectious conjunctivitis in adults are viral and self-limited; these cases do not require antimicrobial treatment.

• Antiviral medication may be used to treat more serious forms of conjunctivitis, such as conjunctivitis caused by herpes simplex virus or
varicella-zoster virus.

Question 19

Conjunctivitis (Pink eye)

symptoms

Answer 19

• Symptoms: Depending on the cause of viral conjunctivitis, some patients may have additional symptoms or conditions, such as the following:
Common cold, flu, or other respiratory infection

Question 20

Conjunctivitis (Pink eye)

Pharyngoconjunctivial fever

Answer 20

• Pharyngoconjunctivial fever – a syndrome that can produce conjunctivitis as well as a fever and sore throat, and is most commonly caused by
infection with adenovirus serotypes 3, 4, and 7
.

Question 21

Conjunctivitis (Pink eye)

Epidemic keratoconjunctivitis

Answer 21

• Epidemic keratoconjunctivitis – a more severe type of conjunctivitis, commonly caused by infection with adenovirus serotypes 8, 19, and 37

Question 22

Conjunctivitis (Pink eye)

Acute hemorrhagic conjunctivitis

Answer 22

• Acute hemorrhagic conjunctivitis – a type of conjunctivitis that is often associated with large epidemics worldwide, especially in the tropical
and subtropical regions. The viruses most commonly associated with it include enterovirus 70, coxsackievirus A24, and adenoviruses.

Question 23

Conjunctivitis (Pink eye)

Herpetic keratoconjunctivitis

Answer 23

• Herpetic keratoconjunctivitis – a type of conjunctivitis associated with herpes simplex virus and blister-like lesions on the skin; it may affect
only one eye.

Question 24

Conjunctivitis (Pink eye)

Rubella and rubeola (measles)

Answer 24

• Rubella and rubeola (measles) – conjunctivitis can occur with these viral rash illnesses which are usually accompanied by rash, fever, and
cough

Question 25

Cytomegalovirus (CMV)

Answer 25

• CMV is a member of the herpesvirus family, which includes herpes simplex virus types 1 and 2, varicella- zoster virus, and Epstein-Barr virus.

Question 26

Cytomegalovirus (CMV) transmisson

Answer 26

• Transmission: by direct contact with infectious body fluids, such as urine, saliva, blood, tears, semen, and breast milk. • CMV can be transmitted sexually and through transplanted organs and blood transfusions. • CMV, is a common virus that infects people of all ages. Over half of adults have been infected with CMV by age 40.

Question 27

Cytomegalovirus (CMV) symptoms

Answer 27

• Symptoms: Most people infected with CMV show no signs or symptoms.

Question 28

Cytomegalovirus (CMV) congenital cmv

Answer 28

• Congenital CMV: Occurs when a baby is born with cytomegalovirus (CMV) infection. About one out of every 200 babies is born with congenital CMV infection. About one in five babies with congenital CMV infection will have long-term health problems.

Question 29

Cytomegalovirus (CMV) prevention

Answer 29

• Prevention: CMV is common in children and can be found in especially high amounts in young children’s saliva and urine. Avoiding contact with saliva and urine from young children might reduce the risk of CMV infection. • No treatment exist currently.

Question 30

Epstein-Barr virus (EBV) symptoms

Answer 30

* EBV, is one of the most common human viruses in the world. It spreads primarily through saliva. * EBV infection could result in mononucleosis (kissing disease) and symptoms include: * extreme fatigue * fever * sore throat * head and body aches * swollen lymph nodes in the neck and armpits * swollen liver or spleen or both * rash

Question 31

Epstein-Barr virus (EBV) pathology

Answer 31

Pathology: EBV can cause infectious mononucleosis, also called mono, and other illnesses. Infection in most persons with EBV may persist in their lifetime without symptoms. • Mono caused by EBV is most common among teens and adults. • People with weakened immune systems may develop more severe symptoms and complications from EBV infection. Also, they may experience more severe illness due to EBV infection.

Question 32

Epstein-Barr virus (EBV) nervous disorder

Answer 32

* Nervous disorder * EBV infection can affect a person’s brain, spinal cord, and nerves resulting in conditions such as: * Viral meningitis (swelling of the tissues that cover the brain and spinal cord) * Encephalitisexternal icon (swelling of the brain) * Optic neuritisexternal icon (swelling of the eye nerve) * Transverse myelitisexternal icon (swelling of the spinal cord) * Facial nerve palsiesexternal icon (paralysis of facial muscles) * Guillain-Barré syndrome (an immune system disease) * Acute cerebellar ataxiaexternal icon (sudden uncoordinated muscle movement) * Hemiplegia (paralysis on one side of the body) * Sleep disorders

Question 33

Epstein-Barr virus (EBV) hematological system

Answer 33

• Hematological System • EBV infection can affect a person’s blood and bone marrow. The virus can cause the body to produce an excessive number of white blood cells called lymphocytes (lymphocytosis). • EBV can also weaken the immune system, making it more difficult for the body to fight infection

Question 34

Epstein-Barr virus (EBV) cancers

Answer 34

Cancers associated with EBV infection include: • Burkitt’s lymphomaexternal icon (cancer of the lymphatic system) • Nasopharyngeal carcinomaexternal icon (cancer of the upper throat) • Hodgkin’s diseaseexternal icon and non-Hodgkin’s lymphomaexternal icon (cancers of the lymphatic system) • Post-transplant lymphoproliferative disorder (white blood cells are produced in excess) • Other tumors including leiomyosarcomas (cancer in the soft tissue) and T-cell lymphoma

Question 35

Epstein-Barr virus (EBV) complications

Answer 35

Complications of EBV infection include: • Acute bacterial sinusitisexternal icon (bacterial infection of the sinus cavities) • Suppurative lymph nodes (swelling of lymph nodes) • Mastoiditisexternal icon (bacterial infection of the mastoid bone of the skull) • Sialadenitisexternal icon (swelling and injury of salivary glands) • Blockage of the air passages in the nose and throat

Question 36

Measles taxonomy and history

Answer 36

* Measles virus has a single strand negative-sense RNA, belonging to the family Paramyxoviridae. * It can lead to serious health complications in humans, or even death. * In 2019, the estimated number of measles cases was over 9 million people, resulting in the death of 207,500 people (mostly children). * The health consequences of measles infection can be lifelong, including economic losses for individuals, families and societies. * Measles are amongst the “vaccine-preventable diseases” (VPD). Implying that if vaccine is delivered on schedule and as recommended, it can keep people from catching and giving these diseases to others

Question 37

Measles disease

Answer 37

* Disease: Health problems caused by these diseases overlap. * Each of them can cause brain damage, deafness, and blindness. * Measles can cause pneumonia and diarrhea. * Measles vaccine is safe and proven effective in helping the body build protection against these viruses to prevent disease

Question 38

Polio taxonomy

Answer 38

* Poliovirus is a member of the Enterovirus genus, family Picornaviridae. * Enteroviruses are transient inhabitants of the gastrointestinal tract, and are stable at acid pH. * Picornaviruses are small, ether-insensitive viruses with an RNA genome. * Poliovirus causes polio, or poliomyelitis, a highly infectious disease. * Poliomyelitis, is a disabling and life-threatening disease. * The virus spreads from person to person and can infect a person’s spinal cord, causing paralysis (can’t move parts of the body). * There are three poliovirus serotypes (PV1, PV2, and PV3) with minimal heterotypic immunity between them. That is, immunity to one serotype does not produce significant immunity to the other serotypes

Question 39

Polio infection and transmission

Answer 39

Infection and Transmission • Poliovirus infects only humans. It is spread by the fecal-oral and respiratory routes. Infection is more common in infants and young children. • Polio occurs at an earlier age among children living in poor hygienic conditions. In temperate climates, poliovirus infections are most common during summer and autumn. In tropical areas, the seasonal pattern is less pronounced

Question 40

Polio Symptoms

Answer 40

* Symptoms: * most people who get infected with poliovirus (about 72 out of 100) will not have any visible symptoms. * About 1 out of 4 people (or 25 out of 100) with poliovirus infection will have flu-like symptoms that may include: * Sore throat, Fever, Tiredness, Nausea, Headache, Stomach pain • These symptoms usually last 2 to 5 days, then go away on their own, but if persist can result in paralysis

Question 41

Polio pathology / complications

Answer 41

About 1% of people will have weakness or paralysis in their arms, legs, or both. The paralysis can lead to permanent disability and death. • About 2 to 10% of people who have paralysis from polio die, because the virus affects the muscles that help them breathe. • The incubation period of nonparalytic poliomyelitis is 3 to 6 days. For the onset of paralysis in paralytic poliomyelitis, the incubation period usually is 7 to 21 days. • A smaller proportion of people (about 1%) with poliovirus infection will develop other, more serious symptoms that affect the brain and spinal cord:

Question 42

Polio pathology / complications paresthesia

Answer 42

Paresthesia (feeling of pins and needles in the legs

Question 43

Polio pathology / complications meningitis

Answer 43

Meningitis (infection of the covering of the spinal cord and/or brain): occurs in about 4% people with poliovirus infectio

Question 44

Polio pathology / complications paralysis

Answer 44

* Paralysis (can’t move parts of the body) or weakness in the arms, legs, or both, occurs in about 1 out of 200 people with poliovirus infection * Paralysis is the most severe symptom associated with polio, because it can lead to permanent disability and death.

Question 45

Polio pathology / complications post-polio syndrome

Answer 45

Post-polio syndrome: occurs in children who seem to fully recovered. They can develop new muscle pain, weakness, or paralysis as adults, 15 to 40 years later.

Question 46

Polio vaccines

Answer 46

* Vaccines: There are two types of vaccine that can prevent polio: * Inactivated poliovirus vaccine (IPV) given as an injection in the leg or arm, depending on the patient’s age. * Oral poliovirus vaccine (OPV) is still used throughout much of the world. * Almost all children (about 99%) who get all the recommended doses of the inactivated polio vaccine will be protected from polio.

Question 47

Hand, foot, and mouth disease

Answer 47

* Hand, foot, and mouth disease caused by Coxsackievirus A16, or Enterovirus 17 (+ ssRNA virus) * is common in children under 5 years old, but anyone can be infected. * The illness is usually not serious, but it is very contagious. It spreads quickly at schools and day care centers

Question 48

Hand, foot, and mouth disease fever and flu-like symptoms

Answer 48

1. Fever and flu-like symptoms • Children often get a fever and other flu-like symptoms three to six days after contracting virus. • Symptoms may include: • Fever, Eating or drinking less, Sore throat, Feeling unwell • Other symptoms may appear over the next few days

Question 49

Hand, foot, and mouth disease mouth sores

Answer 49

2. Mouth sores • Children may get painful mouth sores (herpangina), one or two days after the onset of fever. These sores usually start as small red spots, often in the back of their mouth, that blister and can become painful. • Signs on children with painful blisters are: • Painful swallowing, Not eating or drinking • Drooling more than usual, Only wanting to drink cold fluids

Question 50

Hand, foot, and mouth disease skin rash

Answer 50

Skin rash: children may get a skin rash on the palms of the hands and soles of the feet. It may also show up on the knees, elbows, buttocks, or genital area

Question 51

Hand, foot, and mouth disease prevention

Answer 51

Keep blisters or scabs clean and avoid touching them

Question 52

Human papillomavirus (HPV)

Answer 52

• HPV, is a DNA virus in the family Papillomaviridae The virus commonly genital wart and could result to cancers later in life. • Every year in the United States, HPV causes about 36,000 cases of cancer in men and women.

Question 53

Human papillomavirus (HPV) transmission

Answer 53

HPV is spread through intimate skin-to-skin contact such as vaginal, anal, or oral sex with someone who has the virus, even if they don’t have signs or symptoms. • Some HPV infections can lead to cancer • Mother and daughter smiling and embracing

Question 54

Human papillomavirus (HPV) pathology

Answer 54

* Pathology: Most HPV infections (9 out of 10) go away by themselves within 2 years. But sometimes, HPV infections will last longer and can cause some cancers. * HPV infections can cause cancers of the: * Cervix, vagina, and vulva in women * Penis in men * Anus in both women and men * Back of the throat (called oropharyngeal cancer), including the base of the tongue and tonsils, in both men and women

Question 55

Human papillomavirus (HPV) complications

Answer 55

• Cancer usually takes years, even decades, to develop after a person gets HPV. There is no way to know who will develop cancer or other health problems from HPV. • People with weakened immune systems (like people living with HIV/AIDS) may be less able to fight off (clear) HPV infections, and more likely to develop health problems caused by HPV. • Every year in the United States: • Nearly 200,000 women are diagnosed with a cervical precancer • 11,000 women are diagnosed with cervical cancer caused by HPV • Over 4,000 women die from cervical cancer • More than 4 out of every 10 cases of cancer caused by HPV occur among men. • Every year in the U.S., over 14,000 men get cancers caused by HPV.

Question 56

Human papillomavirus (HPV) vaccination

Answer 56

• Vaccination at age 11–12 years can protect children from HPV infection and associated cancers. • HPV vaccination can prevent over 90% of cancers caused by HPV, as well as anal, vaginal, cervical, and vulvar precancers (abnormal cells that can lead to cancer) • More than 9 of every 10 cases of cervical cancer are caused by HPV. Almost all cervical cancer can be prevented by HPV vaccination.

Question 57

Human parainfluenza viruses (HPIVs taxonomy

Answer 57

Human parainfluenza viruses (HPIVs) belong to the Paramyxoviridae family.

Question 58

Human parainfluenza viruses (HPIVs classificaiton

Answer 58

They are enveloped RNA viruses. • Classification: There are four types (1 to 4) and two subtypes (4a and 4b) of HPIVs. The clinical and epidemiological features for each HPIV type can sometimes vary. • HPIVs commonly infect infants and young children and persons with weakened immune systems. However, anyone can get HPIV infection

Question 59

Human parainfluenza viruses (HPIVs transmission

Answer 59

* Transmission: HPIVs spread from an infected person to other people through infectious droplets or by airborne: * the air by coughing and sneezing * close personal contact, such as touching or shaking hands * fomite contamination: touching objects or surfaces with the viruses on them then touching your mouth, nose, or eyes * The incubation period, the time from exposure to HPIV to onset of symptoms, is generally 2 to 7 day

Question 60

Human parainfluenza viruses (HPIVs symptoms and pathology

Answer 60

* Symptoms / Pathology: Human parainfluenza viruses (HPIVs) commonly cause respiratory illnesses in infants and young children. Symptoms may include fever, runny nose, and cough. Patients usually recover on their own. However, HPIVs can also cause more severe illness, such as croup or pneumonia. * HPIV-1 and HPIV-2 are most often associated with croup. HPIV-1 often causes croup (upper airway infection) in children, whereas HPIV-2 is less frequently detected. Both types can cause upper and lower respiratory tract illnesses. People with upper respiratory tract illness may have cold-like symptoms. * HPIV-3 is more often associated with bronchiolitis, bronchitis, and pneumonia. * HPIV-4 is not recognized as often but may cause mild to severe respiratory tract illnesses.

Question 61

Human parainfluenza viruses (HPIVs vaccines

Answer 61

none

Question 62

Middle East Respiratory Syndrome (MERS)

Answer 62

* Middle East Respiratory Syndrome (MERS) is viral respiratory illness in humans. * It is a species of the coronavirus that infect humans, bats and carme

Question 63

Middle East Respiratory Syndrome (MERS) transmission

Answer 63

transmission: through contact with virus-contaminated body fluids and respiratory secretion

Question 64

Middle East Respiratory Syndrome (MERS) epidemiology

Answer 64

• Epidemiology: It was first reported in Saudi Arabia in 2012 and has since spread to several other countries, including the United States. • Countries in or near the Arabian Peninsula that have reported MERS cases: Bahrain, Iran, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, United Arab Emirates (UAE), and Yemen. • Countries outside of the Arabian Peninsula with travel-associated MERS cases: Algeria, Austria, China, Egypt, France, Germany, Greece, Italy, Malaysia, Netherlands, Philippines, Republic of Korea, Thailand, Tunisia, Turkey, United Kingdom (UK), and United States of America (USA

Question 65

Middle East Respiratory Syndrome (MERS) symptoms

Answer 65

• Symptoms: Most people infected with MERS-CoV developed severe respiratory illness, including fever, cough, and shortness of breath. Many of them have died.

Question 66

Middle East Respiratory Syndrome (MERS) clinical presentation

Answer 66

• Clinical Presentation: A wide clinical spectrum of MERS-CoV infection has been reported ranging from asymptomatic infection to acute upper respiratory illness, and rapidly progressive pneumonitis, respiratory failure, septic shock and multi-organ failure resulting in death. • At hospital admission, common signs and symptoms include fever, chills/rigors, headache, non-productive cough, dyspnea, and myalgia. • Other symptoms can include sore throat, coryza, nausea and vomiting, dizziness, sputum production, diarrhea, and abdominal pain. • Atypical presentations including mild respiratory illness without fever and diarrheal illness preceding development of pneumonia have been reported.

Question 67

Mumps taxonomy

Answer 67

* Mumps is a viral illness caused by a paramyxovirus, a member of the Rubulavirus family. * The average incubation period for mumps is 16 to 18 days, with a range of 12 to 25 days

Question 68

Mumps transmission

Answer 68

Transmission: mumps virus replicates in the upper respiratory tract and is transmitted person to person through direct contact with saliva or respiratory droplets of a person infected with mumps

Question 69

Mumps symptoms

Answer 69

Symptoms: Mumps is a contagious disease that is caused by a virus. It typically starts with a few days of fever, headache, muscle aches, tiredness, and loss of appetite. • Then most people will have swelling of their salivary glands (often referred to as parotitis when the parotid gland, located in front and below the ear, swells). This is what causes the puffy cheeks and a tender, swollen jaw. • Nonspecific prodromal symptoms may precede parotitis by several days, including low-grade fever which may last 3 to 4 days, myalgia, anorexia, malaise, and headache. • Parotitis usually lasts on average 5 days and most cases resolve after 10 days.

Question 70

Mumps complications

Answer 70

Complications • Mumps complications include meningitis, encephalitis, pancreatitis, and hearing loss. • Complications can occur in the absence of parotitis and occur less frequently in vaccinated patients. • Some complications of mumps are known to occur more frequently among adults than children.

Question 71

Norovirus

Answer 71

• Norovirus is a very contagious virus that causes vomiting and diarrhea. • It belongs to the order: Picornavirales and family Caliciviridae. • Norovirus illness is commonly called “food poisoning,” “stomach flu,” or “stomach bug.” Noroviruses are the leading cause of foodborne illness, but other germs and chemicals can also cause foodborne illness. • Norovirus infects about 685 million persons worldwide, resulting in about 200,000 death yearly.

Question 72

Norovirus transmission

Answer 72

Transmission: • Having direct contact with an infected person • Consuming contaminated food or water • Touching contaminated surfaces and then putting your unwashed hands in your mout

Question 73

Norovirus symptoms

Answer 73

``` Common symptoms are: • Diarrhea • Vomiting • Nausea • Stomach pain ```

Question 74

Norovirus prevention

Answer 74

food hygiene

Question 75

Rotavirus

Answer 75

• Rotaviruses are non-enveloped viruses, possessing a triple-layered capsid, and a segmented RNA genome. The virus is stable in the environment. • Rotavirus has a characteristic wheel-like appearance when viewed by an electron microscope. • The name rotavirus is derived from the Latin word rota, meaning “wheel.

Question 76

Rotavirus epidemiology

Answer 76

• Epidemiology • The primary mode of transmission is the fecal-oral route, usually through direct contact between people. Because the virus is stable in the environment, transmission also can occur through ingestion of contaminated water or food and contact with contaminated surfaces or objects. • Rotavirus disease is characterized by vomiting and watery diarrhea for three to eight days. Fever and abdominal pain also are common. Additional symptoms include loss of appetite and dehydration

Question 77

Rotavirus symptoms

Answer 77

``` • Symptoms of dehydration include: • decreased urination • dry mouth and throat • feeling dizzy when standing up • crying with few or no tears and • unusual sleepiness or fussiness. • Rotavirus commonly causes severe, watery diarrhea and vomiting in infants and young children. Children may become dehydrated and need to be hospitalized and can even die. ```

Question 78

Rotavirus vaccination

Answer 78

Vaccination: help protect children from infection

Question 79

Rubella taxonomy

Answer 79

Rubella virus is an enveloped, positive-stranded RNA virus classified as a Rubivirus in the Matonaviridae family

Question 80

Rubella transmission

Answer 80

Transmission: Is primarily through direct or droplet contact from nasopharyngeal secretions. Humans are the only natural hosts

Question 81

Rubella symptoms

Answer 81

Symptoms: Rubella is a contagious disease caused by a virus. Most people who get rubella usually have a mild illness, with symptoms that can include a low-grade fever, sore throat, and a rash that starts on the face and spreads to the rest of the body

Question 82

Rubella pathology

Answer 82

Pathology: Rubella is a viral illness that can lead to complications and death. It is characterized by a mild, maculopapular rash along with lymphadenopathy, and a slight fever. The rash usually starts on the face, becomes generalized within 24 hours, and lasts a median of 3 days; it occurs in 50% to 80% of infected people.

Question 83

Rubella complications

Answer 83

Complications: Rubella can cause a miscarriage or serious birth defects in a developing baby if a woman is infected while she is pregnant.

Question 84

Rubella vaccine

Answer 84

Vaccine: The best protection against rubella is MMR (measles-mumps-rubella) vaccine.

Question 85

Human Coronavirus

Answer 85

• Coronaviruses are named for the crown-like spikes on their surface. There are four main sub-groupings of coronaviruses, known as alpha, beta, gamma, and delta. • Human coronaviruses were first identified in the mid-1960s. • Human Coronavirus Types • 229E (alpha coronavirus) • NL63 (alpha coronavirus) • OC43 (beta coronavirus) • HKU1 (beta coronavirus) • Other human coronaviruses • MERS-CoV (the beta coronavirus that causes Middle East Respiratory Syndrome, or MERS) • SARS-CoV (the beta coronavirus that causes severe acute respiratory syndrome, or SARS) • SARS-CoV-2 (the novel coronavirus that causes coronavirus disease 2019, or COVID-19) • People around the world commonly get infected with human coronaviruses 229E, NL63, OC43, and HKU1. • Sometimes coronaviruses that infect animals can evolve and make people sick and become a new human coronavirus. Three recent examples of this are 2019-nCoV, SARS-CoV, and MERS-CoV

Question 86

Symptoms of COVID-19

Answer 86

* People with COVID-19 have had a wide range of symptoms reported – ranging from mild symptoms to severe illness. * Symptoms may appear 2-14 days after exposure to the virus. Anyone can have mild to severe symptoms. * Symptoms of COVID-19 may include: * Fever or chills (most common) * Cough (2nd rated) * Shortness of breath or difficulty breathing * Fatigue * Muscle or body aches * Headache * New loss of taste or smell * Sore throat * Congestion or runny nose * Nausea or vomiting * Diarrhea * Persistent pain or pressure in the chest * New confusion * Inability to wake or stay awake * Pale, gray, or blue-colored skin, lips, or nail beds, depending on skin tone

Question 87

Influenza (Flu) Viruses taxonomy and general stuff

Answer 87

• Influenza (flu) is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness, and at times can lead to death. • Influenza belongs to the virus family Orthomyxoviridae. • The genome is minus strand RNA, and unique from other members of the group by replicating its RNA in the nucleus. • There are two main types of human flu viruses: types A and B. The flu A and B viruses that routinely spread in people are responsible for seasonal flu epidemics each year

Question 88

Influenza (Flu) Viruses signs and symptoms

Answer 88

• Flu signs and symptoms usually come on suddenly. They may include: • Fever/chills • Cough • Sore throat • Runny or stuffy nose • Muscle or body aches • Headaches • Fatigue (tiredness) • Some people may have vomiting and diarrhea, though this is more common in children than adult • Flu Complications • Most people who get flu will recover in a few days to less than two weeks, but some people will develop complications (such as pneumonia) as a result of flu, some of which can be life-threatening and result in death

Question 89

HIV

Answer 89

HIV stands for human immunodeficiency virus. HIV is a member of the genus Lentivirus, part of the family Retroviridae. It is composed of two copies of positive-sense single-stranded RNA.

Question 90

HIV

Answer 90

Transmission: HIV is commonly transmitted via unprotected sexual activity, blood transfusions, hypodermic needles, and from mother to child

Question 91

HIV

Answer 91

Symptoms of HIV include, fever, chills, night sweat, muscle ache, sore throat, swollen lymph nodes and rash • Two types of HIV exist, HIV-1 and HIV-2 (West Africa). They both evolved independently from Simian immunodeficiency virus (SIV). • HIV-1 is more common and depletes the host immune system, exposing the person to infections by other viruses, bacteria, protozoa, fungi, etc. • HIV weakens a person’s immune system by destroying important cells that fight disease and infection (helper T cells, macrophages, chemokines, etc. There is currently no effective cure for HIV. But with proper medical care, HIV can be controlled. • If HIV is not controlled or treated, it can lead to AIDS (acquired immunodeficiency syndrome). When the CD4 lymphocyte count falls below 200 cells/ml of blood, the HIV host has progressed to AIDS. • CD4 T-cell depletion and chronic inflammation are the two signature events that drive HIV pathogenesis and progression to AIDS. • Importantly, the virus can remain inactive (latent) in these productively infected cells for long periods. • Infection of the cells of the CNS cause acute aseptic meningitis, subacute encephalitis, vacuolar myelopathy and peripheral neuropathy. Later it leads to even AIDS dementia complex