MORBILLO: causes and symptoms, incubation, contagion and vaccine prevention

The measles it's a infectious disease caused by the a virus belonging to the genus of Morbillivirus, a highly virus contagious which can infect people of all ages, whose transmission occurs through droplets of saliva or secretions. It is part of the exanthematous diseases, and can cause symptoms ranging from simple rash - exanthema -, until complications organic a lot serious, that endanger the life of the affected person. Prevention is possible and is carried out thanks to the vaccine, which allows you to develop anti-measles antibodies and escape contagion.

Measles

What is measles?

What is measles? The measles is a highly contagious viral infectious disease. It affects people of all ages, including adults and the elderly, although it is particularly common in unvaccinated infants and children. It can cause symptoms ranging from simple rash, until complications organic a lot severe (pneumonia, encephalitis, hepatitis), that endanger the life of the affected person. It is part of the exanthematous diseases, together with rubella, scarlet fever, chicken pox, fourth disease - also called scarlet fever -, fifth disease e sixth disease. 

Measles transmission, contagion and incubation

Measles is caused by the Paramixovirus, a virus belonging to the genus of Morbillivirus (family of Paramyxoviridae). It is a highly contagious virus, humans are the natural host of the virus and there are no animal reservoirs of the disease. The infection can occur in people of all ages even if its incidence is greater in age pediatric (babies and children) rather than in the adults; the infection it is very rapid: the infection is transmits by droplets of saliva or secretions produced by an infected host.

After the introduction of the vaccination the incidence of measles has decreased significantly although it is now increasing again with cases reported mainly in populations with low vaccination coverage rates.

After contact with an infected person, the virus begins to replicate in the respiratory tract, after 2-4 days it replicates in the tissues lymphatics (mainly in the lymph nodes) and this is followed by a spread of the virus in the blood (viraemia), through which it reaches various organs before manifesting itself with the characteristic rash. 

The period of incubation measles lasts from 7 to 14 days, the infected subject turns out to be contagious 3-5 days before the rash appears and stays that way for another 4 days after it appears of the exanthem.

Measles Symptoms

How does measles manifest itself? What are the main symptoms? In the initial phase the classical triad of symptoms is cough, nasal congestion and inflammation of the conjunctiva, in addition to clearly the temperature very high. Here are the main early symptoms of measles:

  • conjunctivitis
  • cough
  • nasal congestion
  • high fever (body temperature even higher than 40 ° C): lasts for 4-7 days
  • malaise
  • asthenia (severe fatigue)
  • hyporexia (loss of appetite)
  • photophobia (discomfort in the presence of light)
  • edema around the eyes
  • myalgia (muscle pain).

THE symptoms change with the passage of time: after 2-4 days it appears the enantema which is characterized by the presence of grayish-white dots within the mouth (spots of Koplik).

Red spots in child with measles

The rash, red dots at times confluent on the chest of a child with measles.

Following appears the typical measles rash, L'rash characterized by small red patches on the skin, often described as small red dots which occur initially at face, to the neck and behind the ears and then spread to end, that is to hands and feet.

Koplik spots

Koplik's spots, small white spots on the inner wall of the cheeks.

It is important to know that people with immune system defects may not develop some classic measles symptoms such as the rash. The rash lasts 4 to 7 days, sometimes resolves with the desquamation of the skin. The complications they arise because the virus depresses the immune response of the infected host causing the reactivation of latent infections or bacterial over-infections; they are also more frequent in children <5 years old, in subjects> 20 years old or with immunodeficiencies, malnutrition, Vitamin A deficiency.

Complications of measles

Unfortunately, the measles it does not just give skin manifestations and a bit of fever: it often results in terrible complications that endanger the life of the affected person. There pneumonia, due to the virus itself or bacterial, is the complication more frequently. It manifests itself with difficulty in breathing, more or less productive cough, fever.

Other fearsome complications of measles are:

  • middle ear infections
  • laryngotracheobronchitis
  • sinusitis
  • diarrhea
  • hepatitis
  • keratitis which can lead to blindness
  • diseases of the nervous system (encephalomyelitis, subacute sclerosing panencephalitis)
  • myocarditis or pericarditis
  • appendicitis
  • acute pancreatitis

About 1 in 1000 patients develops an encephalitis, which often leads to permanent brain damage and is fatal in 10% cases.

Measles Diagnosis

There diagnosis of the measles is based on the clinical picture, confirmation is obtained with serological tests (research of antibodies anti-morbillivirus) and culture tests or with PCR (polymerase chain reaction). In acute infection there is the positivization antibodies IgM, which can be positive starting from the 3rd day from the onset of the rash and remain positive for about a month.

The virus culture on throat swab or tampon nasal come on urine it allows to isolate the virus, confirms the diagnosis and can be useful for epidemiological purposes, ie to provide doctors with precise data on the incidence of this disease. If available, PCR on blood, nasopharyngeal swab, urine allows for a quick confirmation of the diagnosis.

Blood tests may show a increase gods lymphocytes (lymphocytosis) and platelets (thrombocytosis), in some cases there may also be an increase in liver enzymes (elevated transaminases). In case of suspected complications the radiography of the Chest and the lumbar puncture.

Measles therapy

What are the main ones remedies is care for measles? There therapy of the measles is supportive and consists of treatment of the temperature - through antipyretics such as paracetamol - and in maintaining an adequate state of hydration.

Hospitalization it may be needed in children and people with complications. In the cases of severe dehydration (for vomiting, diarrhea, loss of appetite) one may be needed rehydration intravenously via saline or glucose solutions. In case of bacterial over-infections these must be treated with adequate antibiotic therapy.

L'isolation it is indicated from 3-5 days before the onset of the rash to 5 days later in healthy subjects and for the duration of the disease in immunocompromised subjects. There are not antiviral drugs approved for its treatment.

Since vitamin A deficiency is a risk factor for developing complications or severe forms, measles is indicated in people with measles supplementation with Vitamin A.

Measles prevention: vaccination

In immunocompetent individuals - that is, with a functioning immune system - primary infection confers an immunity that lasts for lifetime. The newborn receives the maternal antibodies on the way trans-placental, this immunity lasts for almost the entire first year of life; subsequently the susceptibility to measles is high.

There prophylaxis of infection occurs through the vaccination. The measles vaccine belongs to the live attenuated vaccines and exists in the form of a vaccine complex with other vaccines (measles, mumps, rubella and chicken pox or MPRV).

The vaccination schedule Italian currently provides two doses of MPRV vaccine:

  • the first dose between 12 and 15 months of age,
  • the second dose at 5-6 years of age.

Side Effects of the Measles Vaccine

Which side effects can have the measles vaccine? Subsequent to the vaccine, mild localized reactions such as swelling, pain, redness at the injection site and also fever, rash mild, swollen al face or behind the neck (6-14 days after infection).

Rare manifestations are the convulsions secondary to fever, joint pain, thrombocytopenia. Finally, there are very rare serious reactions can be the manifestations allergic.

As for the myth of an alleged correlation between autism and vaccines, many studies have been conducted any relationship between MMR vaccine is excluded (measles, mumps, rubella) and autism

Contraindications of measles vaccination

What are the contraindications to the measles vaccine? Contraindications to the vaccine are:

  1. subjects with a allergic reaction severe at the first dose of the vaccine,
  2. individuals allergic to neomycin or other components,
  3. patients with rare hereditary problems of fructose intolerance,
  4. pregnant women (the vaccine should be postponed until after delivery).

Also, it is helpful to tell the vaccinator if the person has a tumor, has a number bass of platelets, recently received a transfusion of blood, immunoglobulins or another vaccine.

In susceptible individuals who have come into contact with measles cases, the post exposure prophylaxis by the vaccine, effective when administered within three days of exposure. Infants 6 months to 1 year old can also be vaccinated if they have come into contact with a case of measles or in an epidemic, but in this case the dose is not counted and the first valid dose should be given after the age of 12 months.

In subjects who cannot receive the vaccination, the administration of immunoglobulins IgG specific for measles prevents or changes the course of infection if administered within 6 days from contact.

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