Upper Respiratory Tract Infections

The common cold is diagnosed based on the clinical presentation of symptoms. This means that doctors usually rely on the signs and symptoms reported by the patient, such as a runny or stuffy nose, sore throat, cough, and sneezing, to make a diagnosis. There is no specific blood test or stool sample that can definitively diagnose the common cold. Instead, the diagnosis is made based on the characteristic symptoms that are commonly associated with this viral infection.

The statement suggests that the majority (70%) of acute sore throats are caused by viruses. This implies that only a minority (30%) of acute sore throats are caused by other factors, such as bacterial infections. Therefore, the answer "True" is correct as it aligns with the statement provided.

CMV, or Cytomegalovirus, is a common virus that can infect people of all ages. Many individuals who are infected with CMV do not show any symptoms, hence they are considered asymptomatic. This means that they do not experience any noticeable signs of the infection, such as fever, fatigue, or muscle aches. However, even though they do not show symptoms, they can still transmit the virus to others through bodily fluids, such as saliva, urine, or blood. Therefore, it is important to take precautions to prevent the spread of CMV, especially to individuals who may be more vulnerable to severe complications, such as pregnant women or individuals with weakened immune systems.

The most common invader of the nasopharynx is viruses. This is because the nasopharynx is a part of the upper respiratory tract, which is commonly affected by viral infections such as the common cold, influenza, and respiratory syncytial virus (RSV). Bacteria and fungi can also cause infections in the nasopharynx, but viruses are generally more common. "Dirty little phalanges" is not a valid answer and seems to be a humorous option not related to the question.

EBV, also known as Epstein-Barr virus, is primarily transmitted through saliva. This can occur through activities such as kissing, sharing utensils or drinks, or coming into contact with the saliva of an infected person. While EBV can also be found in other bodily fluids like seminal fluid, blood, and feces, the main mode of transmission is through saliva. This is because the virus is commonly present in the saliva of infected individuals and can easily be passed on to others through close contact or sharing of contaminated objects.

Rhinovirus and coronavirus make up more than 50% of colds. This is because these two viruses are highly contagious and easily transmitted through respiratory droplets. Rhinovirus is the most common cause of the common cold, accounting for around 30-50% of cases, while coronavirus, particularly the common human coronaviruses (such as HCoV-OC43, HCoV-229E, etc.), also contribute to a significant portion of colds. These viruses can cause similar symptoms, including runny nose, sore throat, cough, and congestion, which are characteristic of the common cold.

Adenovirus is a common cause of sore throat and can also infect the conjunctiva, leading to pharyngoconjunctival fever. This virus is known to cause respiratory infections and can easily spread through respiratory droplets or close contact with an infected person. It can cause symptoms such as fever, sore throat, cough, and conjunctivitis. Adenovirus infections are usually self-limiting and can be managed with supportive care, such as rest, fluids, and over-the-counter pain relievers.

EBV is structurally and morphologically identical to other herpes viruses, meaning that it shares similar physical characteristics and appearance with them. However, it is antigenically distinct, implying that it possesses unique antigens or proteins on its surface that allow it to be recognized and distinguished from other herpes viruses by the immune system.

Strep. Pyogenes (group A B-hemolytic) is the most common and most important bacteria responsible for pharyngitis. This bacterium is commonly known as Group A Streptococcus and is responsible for causing strep throat. It is highly contagious and can easily spread through respiratory droplets. Strep throat is characterized by symptoms such as sore throat, fever, and swollen tonsils. Prompt diagnosis and treatment with antibiotics are important to prevent complications and the spread of the infection.

Burkitt's lymphoma is associated with Epstein-Barr virus (EBV) and is commonly seen in African children. This type of lymphoma is characterized by rapidly growing tumors in the lymph nodes, jaw, face, and abdomen. It is more prevalent in areas with high malaria incidence and is often associated with chromosomal translocations involving the MYC gene. The association with EBV is thought to play a role in the development of Burkitt's lymphoma, as the virus can lead to uncontrolled cell growth and division.

Ulcers on the hard palate and tongue are a characteristic symptom of hand, foot, and mouth disease. This disease is caused by the coxsackie A virus. The virus is highly contagious and commonly affects infants and young children. It is transmitted through direct contact with respiratory secretions, saliva, or feces of an infected person. The coxsackie A virus specifically targets the mouth, hands, and feet, causing painful ulcers and blisters. Other symptoms may include fever, sore throat, and a rash on the hands and feet.

When cell-mediated immunity is impaired, it means that the body's immune system is unable to effectively respond to and eliminate the CMV infection. Cell-mediated immunity involves the activation of immune cells, such as T cells, which play a crucial role in recognizing and destroying infected cells. Without a properly functioning cell-mediated immune response, the body is unable to control the CMV infection, leading to the development of an infection.

Viral capsid antigen (VCA) is the major antigen for EBV. This antigen is responsible for the formation of the viral capsid, which is the outer covering of the virus. VCA is produced early during EBV infection and is detected by the immune system, leading to the production of antibodies. These antibodies can be used to diagnose EBV infection. Other antigens like early antigen (EA), nuclear antigen (EBNA), and latent antigen (LA) are also present in EBV, but VCA is the most prominent and widely used antigen for diagnostic purposes.

The long-term infection/latency period of EBV is allowed by the prevention of apoptosis of infected cells. This means that the virus is able to inhibit the natural cell death process, allowing infected cells to survive for an extended period of time. By preventing apoptosis, EBV is able to establish a persistent infection and continue replicating within the host.

CMV, also known as cytomegalovirus, is the largest human herpes virus with only one serotype. This means that there is only one strain or type of CMV that infects humans. HSV, or herpes simplex virus, is another type of human herpes virus, but it has two serotypes (HSV-1 and HSV-2). Coxsackie A16 is not a herpes virus, but rather a strain of the enterovirus family. EBV, or Epstein-Barr virus, is also a human herpes virus, but it has multiple serotypes. Therefore, CMV is the correct answer as it is the largest human herpes virus with only one serotype.

Hairy tongue is the condition caused by EBV replication in squamous epithelial cells in the tongue. This condition is characterized by an overgrowth and elongation of the filiform papillae on the surface of the tongue, giving it a hairy appearance. The replication of EBV in the squamous epithelial cells leads to an accumulation of keratin on the papillae, causing them to become elongated and discolored. This condition is usually harmless and resolves on its own, but it can cause discomfort and altered taste sensation.

Mumps is a single-stranded RNA paramyxovirus that is spread through air-borne droplets, salivary secretions, and possibly urine. Measles, rubella, and otitis are not paramyxoviruses and do not match the given description. Therefore, the correct answer is mumps.

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Orchitis is a potential complication of mumps affecting susceptible adults. Mumps is a viral infection that primarily affects the salivary glands, including the parotid glands located near the ears. However, in some cases, the virus can also infect the testicles, leading to orchitis. Orchitis causes inflammation and swelling of the testicles, which can be quite painful. It can also lead to complications such as infertility or reduced fertility in some cases. Therefore, orchitis is a potential complication that can occur in susceptible adults who contract mumps.

EBV replicates in B lymphocytes and attaches to the C3d receptor. C3d is a fragment of the complement protein C3 that is involved in immune responses. The attachment of EBV to the C3d receptor on B lymphocytes allows the virus to enter the cells and replicate, leading to the spread of the infection.