Measles is a highly contagious virus that can seriously harm a person's health, especially young children and those with weakened immune systems. It is essential to comprehend measles's causes and symptoms in order to identify cases early, treat patients effectively, and stop outbreaks. The measles virus (MeV), a member of the Paramyxoviridae family, is the causative agent of the disease and is transmitted by respiratory droplets and direct contact with contaminated secretions. After exposure, fever, cough, runny nose, and conjunctivitis usually develop 10–14 days later, along with the classic measles rash. Early detection of these signs can help prevent serious complications and manage the development of this avoidable illness.

Overview

The measles virus (MeV), also known as rubeola, is a highly contagious virus that infects and infiltrates the respiratory tract. Specifically, its lymphocytes, dendritic cells, and macrophages, which are all white blood cells which are part of the body’s innate and adaptive immune system, and are vital in fighting off infections and pathogens. The hallmark of measles symptoms is; cough, coryza (runny nose), conjunctivitis, and fever (exceeding 38˚C).¹ The organism that causes measles is a member of the Paramyxoviridae family and Morbillivirus genus (these viruses commonly affect breathing).² They are single-stranded with a nonsegmented RNA. While they are highly contagious, measles outbreaks are also highly preventable with the current modern medicine. It is of great importance to identify the measles disease because it is highly contagious and could rapidly spread, threatening public health. Within the public, there are individuals who are immunosuppressed or infants/children who have yet to receive vaccinations and who are at a greater risk of severe symptoms and fatality. 

Causes of measles

The origin of the measles disease comes from the measles virus (MeV), derived from the Paramyxovirinae family and Morbillivirus genus.³ The human CD36 cell acts as the cellular receptor to attract the measles virus, and the MeV attachment to the cells in the respiratory tract is mediated by the hemagglutinin glycoprotein.⁴ MeV antigens can be detected and identified in the lesions of the mucosa (in the mouth) and skin. Research has shown that the appearance of lesions depends on the cell-mediated immune response.⁵ 

MeV is transmitted through airborne respiratory droplets, which include sneezes and coughs. As MeV is contagious and active in the air for up to two hours, the transmission also includes merely breathing the same air that someone who has measles has breathed in. This poses a problem for public health as it can cause cases to multiply rapidly, which leads to an overwhelm in healthcare demand.⁶ On the note of increased healthcare demand, contagious outbreaks of measles alike, often occur due to healthcare workers being exposed to infected patients, then further infecting patients, colleagues, friends, and family. This particular type of transmission is nosocomial, which means the outbreak originates from a hospital. It is considered a public health threat as it contributes to the rapid spread of diseases and also reintroduces the disease into regions that had previously eliminated the spread.⁷ Apart from the hospital, another location that is particularly susceptible to rapid outbreaks is the airport. Airports are also prone to causing outbreaks due to the number of people from various different places coinciding and meeting, causing a greater likelihood of disease transmission.⁸ 

Symptoms of measles

The incubation period describes the time from exposure to MeV to the prodrome period. It lasts on an average of 10 to 14 days. Then the symptom onset signifies the prodrome period, and it lasts for 2 to 4 days with 1 to 7 days as a range. The initial symptoms that are presented oftentimes include fever of beyond 38˚C and the “3 C’s” which are cough, coryza (runny nose), and conjunctivitis (pink eye).⁶ Then, the symptoms further progress including the development of Koplik spots. These spots appear as small white spots and are present within the mouth, on the buccal mucosa (inner cheek). It is a diagnostic feature of measles in its pre-eruptive phase.⁹ The next stage includes the well-known red blotchy measles rash which appears on the face initially and spreads caudally around the skin of the body. These maculopapular lesions are individually distinct but some may converge into a cluster in the upper body. When applied pressure, these lesions would become pale initially. But by day 3 to 4, it does not pale and remains red. In more extreme cases, lesions may peel off in severely involved locations. As for the termination, the rashes fade in the same order, from the top of the body to the bottom.⁶ 

Complications of measles

The common complications from measles contraction typically can include ear infections and diarrhoea. However, in more severe cases with complex complications, it can impact the patient in the long term period. Pneumonia and breathing issues are one of them. As MeV is transmitted through the respiratory tract, it can directly cause inflammatory responses and lasting lethal infections with pneumonia being one of them.¹⁰ 

Encephalitis is also a possible complication for those with measles contraction. Encephalitis is an infection which causes brain swelling and possible brain damage. It can present as having a high fever, headache, muscle joint fatigue, disturbed vision, and hyporeflexia (decreased reflex response). While the primary mechanism of infection of measles is unclear, research suggests that the viral invasion includes neurological cells and infiltration of the lymphs. This hypothesis is supported by the detection of MeV RNA in the cerebrospinal fluid. According to the research from Fisher et al., it can be found that 25% of patients could have permanent neurological damage.¹¹ 

Another severe complication is subacute sclerosing panencephalitis (SSPE). This condition is a progressive brain disorder that is caused by mutant MeV. The mutations in MeV destroy the structure and function of its proteins, causing extensive tissue damage from the inflammatory response in the brain.¹² 

Infants and young children ineligible for vaccinations are at a higher risk of contracting measles and developing further complications. Immunocompromised individuals have an intentionally weakened immune system due to autoimmune diseases like lupus or type 1 diabetes, which causes the body to attack itself. With a weakened immune system, their body is automatically more susceptible to contracting measles and with more severe symptoms and complications. Malnourished children with vitamin deficiencies often have impairments in the immune system which contributes to increased risks of measles case-fatality rates and prolonged excretion of MeV. Measles also in turn contributes to furthering malnutrition as it increases metabolic demands.¹³ 

Prevention and control

The main solution for preventing rapid outbreaks and fatalities is the MMR (Measles, Mumps, and Rubella) vaccine. They are safe and effective in exposing our bodies to live but weakened measles, mumps, and rubella viruses.¹⁴ The purpose of all vaccines is to expose the body to a pathogen with similar antigens, allowing the body to develop an adaptive immune response. This immune response would develop memory cells which would help fight off the disease more effectively and efficiently when exposed to it later on. According to the NHS website, it is suggested that young children receive their first dose of MMR vaccine at the age of 1, then later on between the age of 3 years 4 months and 5 years old. For those who are receiving the vaccine at an older age, it would be most effective to receive 2 doses each 1-month apart.15 The reason that healthcare workers proactively promote and encourage vaccinations is herd immunity. The concept of herd immunity is to protect those who have not or are unable to have vaccinations. As measles is a highly contagious disease, the transmission rate is also high. Hence, susceptible individuals would have a higher chance of contracting the disease. However, when everyone else who is capable of receiving the vaccinations has done so, the transmission rate decreases substantially as the bodies of those vaccinated are able to fight off the virus efficiently, before transmitting it to others. 

People who have contracted measles but with less severe symptoms should stay in quarantine (like at home) to avoid transmission to others. To prevent transmission to people who live in the same place, a designated room of isolation should help with that. As mentioned before, nosocomial outbreaks are oftentimes detrimental to healthcare workers and public health alike. So those with less severe symptoms should stay in isolation to prevent further transmission of the disease in public. And for those with more severe symptoms and complications, it is likely that when being treated in the hospital, an area given with isolation would not be surprising. 

One thing that COVID-19 has taught us is that rapid and efficient outbreak response is key to preventing preventable death and sickness. A good example of rapid health response is Taiwan during the COVID-19 peak. They closed borders in the airport, not allowing non-residents to enter the country. They also used technology to share information about the mask availability in local clinics, to perform surveillance on infected individuals’ exposure to whichever locations etc. ¹⁶ While some may have concerns towards data privacy, it is important to note that surveillance and technology can be used effectively and positively in regards to sharing important information that can prevent further damages, which is crucial in preventing the worst outcomes of an outbreak. 

Summary

Measles is a highly contagious virus that can seriously harm a person's health, particularly in young children and those with weakened immune systems. It is essential to comprehend its causes and symptoms in order to identify it early, treat it effectively, and stop outbreaks. MeV is transmitted by respiratory droplets and direct contact with secretions contaminated with the virus. The most effective preventive measure, which lowers transmission rates and promotes herd immunity, is vaccination with the MMR vaccine. While it may be daunting to receive vaccinations uninformed, it is encouraged to prevent preventable fatalities for susceptible individuals. In order to stop the spread of the infection, quarantine and isolation are advised for affected persons. Taiwan's response during the COVID-19 pandemic serves as an example of how important it is for public health officials to act quickly and use technology to manage epidemics. Future studies on creating more effective measles vaccinations, such as offering easier administration and longer-lasting immunity, as well as investigating possible antiviral therapies will aim to eradicate the disease and lessen its severe symptoms and side effects.