Measles

From Ganfyd

AKA Rubeola

Contents 1 Aetiology 2 Clinical 2.1 Features 2.2 Complications 2.2.1 Abstract of paper describing a 2006 measles outbreak in Germany 2.3 Atypical Disease and Secondary Effects 3 Investigations 3.1 Oral fluid tests 3.2 Blood tests 3.3 Radiology 4 Treatment 4.1 Medical 5 Prevention 5.1 Main public health actions with a case of suspected measles 5.2 Post exposure prophylaxis 6 Notification 7 History of measles infections 8 External links 9 References

Aetiology

A virus. Morbillivirus. A member of the Paramyxovirus family.

Clinical

A child with measles is ill. If a youngster is brought into the consulting room bouncy and bright and proceeds to pull all the books out of the bookcase or papers off the desk while mum tries to demonstrate a few spots, you are not dealing with measles.

Measles is an acute viral illness transmitted easily from person to person by respiratory droplets. Because of the effectiveness of measles vaccine on its own or in combination (as MMR), many UK doctors, nurses and health visitors who qualified since the late 1970s have seen few if any patients with measles.

Incubation period is about 8-13 days, with a further 2 to 4 days before the rash appears. Cases are infectious for about 4 days before and after the rash first presents.

In Sub-Saharan African epidemics measles can cause blindness, malnutrition, cancrum oris and death, especially if there is vitamin A deficiency or HIV present. ^[1]

Features

• fever - hectic, ie multiple high spikes per day
• the child is miserable and clingy
• the face is puffy with a flat expression and an impression of being rather swollen
• a bright red, dense, macular rash starting on the face then spreading down over the trunk and limbs which may become confluent. The macules are 3-4mm irregular patches rather like the rash of amoxicillin sensitivity. The rash may peel, and may be haemorrhagic (a poor prognostic sign). With time, the colour darkens (so-called "staining").
• coryza with rings of yellow mucopus round both nostrils like looking down a shotgun
• laryngotracheobronchitis with usual barking cough which would make a seal jealous
• conjunctivitis with bleary red eyes you might see in a horror movie

Koplik spots are pathognomic. They are small, grain-of-sand sized, irregular, bright red spots with blue-white centres, occurring on the inside of the cheek in the earliest phase of the illness. a picture. They fade as the rash develops and so are unlikely to be seen unless you see the patient before the rash is established.

Older fashioned grannies were said to be able to smell measles. This may be due to the nasal secretions and mouth breathing.

Complications

Complications of measles are common - 1 in 15 cases will suffer a significant complication. Complication rates are highest in infants, lower in children aged one to nine, and then increase again in adolescents and adults. Complications include: ^[3]

• Otitis media (7-9%)^[4]
• Diarrhoea (8%)
• Pneumonia (1-6%), which can be necrotizing eg with pneumomediastinum
• Hepatitis
• Myocarditis
• Convulsions (0.5%) - febrile in nature else encephalitic
• Acute Encephalitis (one per 1000 cases) - an autoimmune demyelinating form with good prognosis is distinguished from an inclusion body form with a poor prognosis (associated with immunosuppression, malignancy)
• Sub-acute sclerosing panencephalitis (SSPE) is a delayed inclusion body encephalitis. According to a 2004 paper cited in the Green Book (November 200 version),^[5] one case of SSPE occured for every 25,000 cases of measles. The rate is higher in children infected under the age of two - one in 8000. SSPE is rare with the wild virus, unreported with the vaccine virus, and uniformly fatal. It presents some years (even 10 years) after the infection with a dementia-like illness, progressing to coma.
• Death - one in 5000 cases according to the Green Book,^[6] which cites a 1985 article. In recent years, according to others,^[7] 1-2 people in every 1000 with reported measles infection died from it. Death from measles is highest in children under one year of age - a group that cannot receive the MMR vaccine - and in those who are immunosuppressed due to disease (e.g. leukaemia) or treatment (e.g. organ transplantation). These children can only be protected through the 'population protection' conferred by high vaccine uptake. The death rate is lower in children aged one to nine years, and rises again in teenagers and adults - which probably explains why the mortality rate has risen in the decades since the introduction of vaccination. (Vaccination reduces the prevalence of illness, so people who are not immune are less likely to get measles in any given year, so that when they do get it, they are more likely to have reached adolescence, and to suffer more severe complications.)

Between 1970 and 1984, 29% of children who died when in first remission from acute lymphocytic leukaemia died from measles or its complications.^[8]

A recent paper in the WHO Bulletin analysed in detail the complication rates in an outbreak in Germany.^[9] Its abstract is reproduced here in full, and the paper is available free at the WHO's website (here),and well worth reading in full.

Abstract of paper describing a 2006 measles outbreak in Germany

Objective To determine morbidity and costs related to a large measles outbreak in Germany and to identify ways to improve the country’s national measles elimination strategy.

Methods We investigated a large outbreak of measles in the federal state of North Rhine-Westphalia (NRW) that occurred in 2006 after 2 years of low measles incidence (< 1 case per 100 000). WHO’s clinical case definition was used, and surveillance data from 2006 and 2001 were compared. All cases notified in Duisburg, the most severely affected city, were contacted and interviewed or sent a questionnaire. Health-care provider costs were calculated using information on complications, hospitalization and physician consultations.

Findings In NRW, 1749 cases were notified over a 48-week period. Compared with 2001, the distribution of cases shifted to older age groups (especially the 10–14 year group). Most cases (n = 614) occurred in Duisburg. Of these, 81% were interviewed; 15% were hospitalized and two died. Of the 464 for whom information was available, 80% were reported as unvaccinated. Common reasons for non-vaccination were parents either forgetting (36%) or rejecting (28%) vaccination. The average cost per measles case was estimated at €373.

Conclusion An accumulation of non-immune individuals led to this outbreak. The shift in age distribution has implications for the effectiveness of measles control and the elimination strategy in place. Immediate nationwide school-based catch-up vaccination campaigns targeting older age groups are needed to close critical immunity gaps. Otherwise, the elimination of measles in Germany and thus in Europe by 2010 will not be feasible. Wichmann et al^[10]

Atypical Disease and Secondary Effects

Atypical measles is often more severe, and usually harder to diagnose. The fever before rash appears is prolonged eg 2-3 weeks, the rash starts peripherally rather than centrally.

Secondary effects are related to suppression of cell mediated immunity and depression of vitamin A levels. These include:

• tuberculosis - esp meningitis, miliary
• secondary bacterial infection esp pneumonia - presenting during the recovery phase
• stomatitis - HSV, candida. Can progress to disfiguring cancrum oris.
• xerophthalmia

Investigations

No diagnostic tests are usually required for clinical purposes, although the virus can be identified from saliva or serum samples during the acute phase.

Oral fluid tests

Oral fluid samples are very easy to take - this can be done by the patient or their parents. They can be used for two purposes:

• To confirm infection during the acute phase. This is seldom required for the purpose of treating the initial patient (or "index case"; but it may be recommended for public health purposes, in order to clarify whether public health measures of prophylactic treatment of contacts is required. A polymerase chain reaction (PCR) test can be performed using the saliva kit sent out by the local health protection unit (or equivalent); or a dry swab or a viral medium swab can be used. (Swabs intended for bacteriology cannot be used for this test.) The test is most likely to be positive early after the onset of symptoms, but may still be positive up to a week after onset.
• To confirm the diagnosis retrospectively. Many illnesses are somewhat similar to measles, and it is vital to establish the prevalence of much genuine measles, in order to evaluate the efficacy of vaccination programmes, and to know when public health action - such as additional MMR campaigns - is required. Like other diseases, Measles should be notified on suspicion. When a cases of measles is notified, a follow-up saliva test is usually recommended. This is taken at least 7 days (usually at least 10 days) after the onset of illness. If measles IgM is identified, this indicates that there has been a recent infection. IgG at this stage usually indicates prior infection or vaccine-induced immunity.

Blood tests

PCR and serology (IgM and IgG) tests can also be performed on blood - but oral fluid tests are at least as sensitive.

Radiology

May be required to assess complications.

Treatment

Medical

Isolate until 48 hours post defervescence. Supportive treatment eg temperature control, mouth and eye care, nutrition/hydration. Consider vitamin A megadose treatment for malnourished.

Antibiotics may be required if there is bacterial superinfection.

Prevention

Measles can be safely and effectively prevented by vaccination - in the UK in 2006 the only available and licensed vaccine is MMR.

Main public health actions with a case of suspected measles

1. Notify the disease as soon as possible to the local HPU so that effective Public Health action can be taken.^[11] This is particularly important if the case attends school or nursery. With notification the HPU will provide you with a salivary antibody test, which can be used from 2-3 weeks after the onset of the rash.
2. Check the vaccination status of household, nursery or other close contacts. MMR offers effective protection against infection if given within 3 days of exposure and may attenuate the disease if given up to 5 days after exposure. This should be offered to any household or nursery contact over the age of nine months who has not had 2 doses of MMR. This also applies to any adult who has not had measles, regardless of age.
3. Two doses of MMR are required for full protection - the first given after the age of 1 year; the second given after the age of 18 months. (In the event of an outbreak or exposure to a case a dose may be given before the age of a year, or a subsequent dose may be given before the age of 18 months, but these do not count towards the two doses needed for long-term protection. See MMR article for more details.)
4. Immunocompromised close contacts and infants under the age of nine months may be given human normal immunoglobulin intramuscularly as soon as possible after exposure. See the HPA's detailed guidance on post-exposure prophylaxis for measles.^[12]
5. Children with measles should be advised not to attend school for 5 days after the appearance of the rash.

Post exposure prophylaxis

Post-exposure prophylaxis is required for certain pregnant women, children and adults with compromised immunity, and certain infants. measles vaccination,^[13][14] and/or Human Normal Immunoglobulin (HNIG) may be required.

See:

• HPA Guidelines individually as below, or via HPA measles guidance page:

• "Immunoglobulin Handbook - Indications and dosage for normal and specific immunoglobulin preparations".
• "Guidance on the management of, and exposure to, rash illness in pregnancy" and
• Post exposure prophylaxis for measles: revised guidance

Notification

Measles should be notified on suspicion.

Confirmatory testing - using the saliva kit described above - will usually be required on notification, since most cases of morbiliform (measles-like) illness are not actually measles (as of January 2006). If an epidemic of measles follows poor uptake of the MMR vaccine this may change. Any cases notified on suspicion which are shown on testing to have prior immunity will be "denotified". A derisory statutory fee is payable for performing the statutory duty of notifying the listed notifiable diseases.

History of measles infections

In the 19th century, while measles was endemic in Europe for many years, in parts of the world it was unknown. A regional pandemic which occurred in the Pacific region, starting in 1875, was referred to as a "virgin soil epidemic" (this seems to be the first epidemic that this phrase was used to refer to), since the population was completely susceptible to measles: about a third of the population of Fiji died in this epidemic, which is elegantly described by Moren et al.^[15]

In 2011 measles re-emerged in Europe and elsewhere.^[16]

External links

• HPA information on measles or:

• Measles-related guidelines
• General information about measles
• Epidemiological Data on measles
• MMR information

• Guidelines for the control of measles outbreaks in Australia - detailed guidelines in pdf format can be downloaded from this page.

References