Paramyxovirus

What is Paramyxovirus?

Paramyxoviruses are a type of virus that hide themselves inside a protective bubble and have a particular genetic structure (single-stranded negative-sense RNA). These types of viruses make copies of themselves in the jelly-like substance within our cells, known as the cytoplasm. They cause diseases that continue to have a significant worldwide death and illness toll. However, the frequency of serious illness due to paramyxoviruses has drastically reduced, thanks to the creation and use of vaccines and medicines.

Although these treatments are available, the choice to receive preventative or follow-up treatment is up to the individual. Because of this, the number of paramyxovirus cases has seen an increase, even in developed countries. The creation of truly effective vaccines against all types of this virus is still underway.

Paramyxoviruses can be classified into two main groups that can cause diseases in humans. One gives rise to the genus Pneumovirus, including the respiratory syncytial virus. The other gives rise to several other genuses including Morbillivirus (responsible for measles), Respirovirus (behind some types of para-influenza) and Rubulavirus, which causes mumps or other forms of para-influenza.

The World Health Organization (WHO) has set a goal to completely eliminate measles and rubella in five different regions by 2020.

What Causes Paramyxovirus?

The Paramyxoviridae family contains two groups, or “subfamilies,” that are significant to humans. These are the Pneumovirinae and the Paramyxovirinae.

The Pneumovirinae subfamily forms the Pneumovirus genus, which includes the respiratory syncytial virus (a common virus that causes infections in the lungs and respiratory tract).

The Paramyxovirinae subfamily forms several genuses or “classes,” of viruses. This includes the Morbillivirus genus (which includes the measles or rubeola virus), the Respirovirus genus (which includes para-influenza viruses 1 and 3), and the Rubulavirus genus (which includes mumps virus and para-influenza viruses 2 and 4).

These viruses are usually spread through respiratory droplets (like when someone with the virus coughs or sneezes) or through direct contact with an infected person.

Risk Factors and Frequency for Paramyxovirus

Measles used to cause 2.6 million deaths around the world before vaccines were introduced. Now, the number of cases in the U.S. is low thanks to vaccination programs. However, some groups of people are hesitant to get vaccinated, leading to occasional spikes in measles cases. Measles spreads through respiratory droplets or close contact, and it can be especially serious for malnourished people, pregnant women, or those with weakened immune systems. People with measles can spread the virus four days before and after they develop a rash.

Mumps used to be much more common before its vaccine was introduced in 1967. In the U.S., the number of reported mumps cases has dropped by 99.8%. Mumps spreads through respiratory droplets, saliva, or touching contaminated objects. One-third of people with mumps won’t show symptoms even though they’re contagious. The virus can cause inflammation in several parts of the body, including the nervous system, salivary glands, and reproductive organs.

The parainfluenza virus is responsible for a substantial amount of acute respiratory infections in children. It causes most cases of croup each year, as well as other respiratory conditions. About 7% of children under 5 in the U.S. are hospitalized for croup each year. The virus spreads through respiratory droplets or direct contact.

Respiratory Syncytial Virus (RSV) causes about 33 million infections and nearly 200,000 pediatric deaths worldwide each year. Most of the time, children under 2 with RSV will experience upper respiratory illness. Sometimes, they may also have lower respiratory symptoms. RSV can infect the same person many times because humans don’t develop long term immunity to it. Premature babies, people with weakened immune systems, and the elderly are more likely to suffer severe effects of RSV. It spreads via respiratory droplets.

Signs and Symptoms of Paramyxovirus

Measles, mumps, croup, and RSV are all kinds of diseases that have unique sets of symptoms.

Measles is usually identifiable by its three key symptoms, also known as the ‘Three Cs’: coughing, coryza (nasal cavity inflammation), and conjunctivitis. People with measles often also have fever and a generalized maculopapular rash. These symptoms usually start to appear 10-12 days after infection, with the rash appearing soon after. Before the skin rash, tiny white spots surrounded by a red halo can sometimes be seen inside the mouth. The rash tends to start on the face and then extend downward. This disease usually gets better on its own within a week of the rash appearing.

Mumps typically begins with a few days of nonspecific symptoms such as fever, headache, muscle pain, weakness, and fatigue, along with loss of appetite. Parotitis, or inflammation of the parotid glands, is the most common manifestation of mumps, representing 70% of cases. This results in swelling on the cheeks, which is often on both sides. Inflammation of Stenson’s ducts inside the mouth is also typical. Additionally, the submaxillary and submandibular glands might also be affected. Recurring sialadenitis is a common complication of parotitis.

Croup usually causes a cough that sounds like a seal barking, voice hoarseness, a harsh, high-pitched sound when breathing in known as stridor, and difficulty breathing. These symptoms are caused by subglottic edema, or swelling of the tissue beneath the vocal folds. Other nonspecific symptoms may include fever, rapid breathing and rapid heart rate.

RSV often leads to upper respiratory symptoms including fever, chills, muscle pain, runny nose, congestion, and cough. In some cases, the virus can cause lower respiratory tract infections, resulting in bronchiolitis or, in severe cases, viral pneumonia. Signs of these more serious conditions include shortness of breath, the use of accessory muscles to breath, and wheezing.

Testing for Paramyxovirus

For a suspected case of measles, several tests may be carried out. One of these is a complete blood count (CBC) that could show a decrease in white cells (leukopenia), a decrease in a type of white blood cell known as lymphocytes (lymphopenia), and a decrease in platelets (thrombocytopenia). This test measures the number of these cells in your blood and can provide information about your overall health.

A comprehensive metabolic panel (CMP) might also be done to check for any electrolyte abnormalities that could be a result of not eating well (poor PO intake) or diarrhea. Electrolytes are minerals in your body that have an electric charge, like sodium, potassium, and calcium, and they need to be maintained in balance for your body to function properly.

A test for IgM antibodies in your blood (serum or plasma) might also be carried out. This test can be done within three days after the rash starts to appear and up to three weeks after. The presence of these antibodies can suggest a recent infection with the measles virus.

For mumps, the diagnosis is usually made based on the symptoms you’re experiencing. Nonetheless, a sample from your mouth (buccal/oral swab) may be taken for further testing, which could include a reverse transcriptase-polymerase chain reaction (RT-PCR) and tests for IgM and IgG antibodies in your blood. These tests can help confirm that you have mumps.

Parainfluenza virus, commonly known as croup, is often diagnosed based on the symptoms. However, an X-ray of your chest might be taken. This can reveal a narrowing of the windpipe (trachea), known as the “steeple sign”.

With Respiratory Syncytial Virus, the diagnosis is also typically based on symptoms. If needed, a rapid antigen test or polymerase chain reaction (PCR) test can be done on a sample taken from your nose. Both these tests can identify the virus that’s causing your symptoms. A chest X-ray might also be done, which could show over-inflation of the lungs and patchy areas where the lungs have collapsed (atelectasis).

Treatment Options for Paramyxovirus

The MMR vaccine, which protects against measles, mumps, and rubella, is usually recommended for prevention. However, it’s important to know that this vaccine isn’t safe for everyone. It’s a type of live virus vaccine, which means it contains weakened versions of the viruses it protects against. Because of this, it’s not safe for pregnant women or people with weakened immune systems.

When it comes to treating these illnesses, the approach usually involves supportive care, which means treating the symptoms to make the patient more comfortable while their body fights off the virus. For measles, this might include supplements of vitamin A, especially if the patient is malnourished.

For mumps, treatment could involve using cold compresses to help with the swelling and medication to help with the pain.

In the case of parainfluenza virus, which can cause a condition known as croup characterized by a harsh, barking cough, treatment might include a medication called racemic epinephrine, a steroid called dexamethasone, oxygen, and humidified air, in addition to supportive care.

Lastly, the respiratory syncytial virus (RSV) is typically managed with supportive care, though there are also some specialized treatments. These can include an antiviral medication called Ribavirin, as well as a treatment known as immune prophylaxis, which involves giving the patient a medication called Palivizumab to help their immune system fight off the virus.

What else can Paramyxovirus be?

When it comes to diagnosing different illnesses, doctors have to consider many possibilities as these illnesses can often show similar symptoms. Here are the various diseases that doctors might need to rule out while diagnosing these specific conditions:

For measles:

• Influenza
• Rubella
• SSPE
• Scarlet fever
• Drug rashes
• Serum sickness
• Roseola infantum
• Infectious mononucleosis
• Erythema infectiosum
• Echovirus
• Coxsackievirus
• Kawasaki
• Rocky mountain spotted fever
• Toxic shock syndrome
• Meningococcemia
• Encephalitis

For mumps:

• Bacterial parotitis
• HIV parotitis
• Mikulicz syndrome
• Salivary gland tumors
• Drug-related parotid enlargement
• Meningitis
• Encephalitis
• Pancreatitis
• Orchitis
• Oophoritis
• Prostatitis
• Nephritis
• Thyroiditis
• Hypothyroidism
• Meningoencephalitis

For parainfluenza virus:

• Influenza
• Pneumonia
• Bronchitis

For croup:

• Airway foreign body
• Epiglottitis
• Retropharyngeal abscess
• Bacterial tracheitis
• Bronchiolitis
• Influenza
• Respiratory Syncytial Virus
• Subglottic stenosis
• Angioedema

For RSV:

• Bronchiolitis
• Pneumonia
• Influenza
• Asthma
• Croup
• Bronchitis

What to expect with Paramyxovirus

Measles, Mumps, Parainfluenza virus (also known as croup) and Respiratory Syncytial virus are all diseases that typically have an excellent prognosis. This means that the outlook or expected outcome is usually good. In most cases, patients with these diseases recover fully.

Possible Complications When Diagnosed with Paramyxovirus

Measles, mumps, parainfluenza virus, and respiratory syncytial virus are all diseases that can lead to serious complications. People with weakened immune systems, newborns, pregnant women, and malnourished children are especially vulnerable to these complications. Here is a quick overview of potential risks for each disease:

Measles Risks:

• Pneumonia
• Blindness
• Encephalitis (brain inflammation)
• Severe diarrhea
• Dehydration
• Severe respiratory infection
• Maternal death
• Spontaneous abortion
• Intrauterine death
• Low birth-weight infants
• Keratoconjunctivitis (eye infection)
• Measles inclusion body encephalitis
• Acute disseminated encephalomyelitis (immune-driven brain inflammation)
• Subacute sclerosing panencephalitis (long term brain inflammation)

Mumps Risks:

• Meningitis
• Encephalitis
• Deafness
• Pancreatitis
• Abscess
• Infertility
• Spontaneous abortion
• Thyroid inflammation

Parainfluenza Virus/Croup Risks:

• Pneumonia
• Pulmonary edema (fluid in lungs)
• Bacterial tracheitis (windpipe infection)
• Death

Respiratory Syncytial Virus Risks:

• Upper and lower respiratory tract infection
• Bronchiolitis (lung infection)
• Viral pneumonia
• Acute respiratory failure

Awareness of these complications can help in early detection and treatment, reducing the potential for severe outcomes.

Preventing Paramyxovirus

It’s crucial for everyone to practice good hand hygiene and cover their coughs or wear a face mask to prevent and protect against diseases. Making use of the latest medical treatments, like vaccines, is also a key part of this. It’s important for the public to be well-informed and understand these precautions. However, the Mumps-Measles-Rubella vaccine is not recommended for pregnant women or people with weakened immune systems.