Ronan Kelly
Retired 2020
Epi-Insight volume 13 issue 9 September 2012
Increase in enteroviral viral meningitis, 2011-2012
Viral meningitis is relatively common and is usually caused by enterovirus infections. In temperate climates, such as Ireland, enterovirus meningitis occurs mainly in late summer, and is most frequent in preschool children. Transmission usually occurs through the faecal-oral route, but may also occur via the respiratory route or contact with a contaminated environment. The incubation period is usually 3-6 days.
The typical presentation includes headache, fever, nausea or vomiting, and occasionally a rash. A history of a sore throat or diarrhoea may precede meningitis symptoms. The majority of infections cause mild or inapparent disease, but severe cases may be hospitalised for diagnosis and management of symptoms. There is no specific drug treatment for most cases of viral meningitis. Recovery is usually complete and rapid. Death caused by viral meningitis is extremely rare. Recently, death was reported in two viral meningitis cases: one in December 2011 where the cause of death was not due to the infection itself, and another in July 2012 where the cause of death was not specified, both occurring in children less than two years of age.
Diagnosis of viral meningitis is based on clinical presentation, cerebrospinal fluid (CSF) findings and detection of a viral pathogen in a CSF, faecal or throat sample. Since November 2005 the National Virus Reference Laboratory (NVRL) has been routinely doing PCR testing for enteroviruses on CSF samples received.
In recent years an increase in the number of viral meningitis notifications made to HPSC is notable with a substantial increase in numbers notified in 2012.
Methods
Annual notifications of viral meningitis between week 1, 2004 and week 31, 2012 were extracted from CIDR. Detailed analysis on notifications during the 12-month period between week 31, 2011 and 02/Aug/2012 was also done using MS Excel. Data presented here are provisional.
Results
Overall, there has been an increase in viral meningitis notifications since 2006, apart from 2007 when relatively few cases (n=45) were reported in comparison to other years during this time period (figure 1). Seasonality is evident with most notifications during summer months. Since May 2011 an increase in monthly notifications is evident with 267 notifications between week 31, 2011 and 02/Aug/2012 compared to 186 for the similar time period in the previous year (August 2010-July 2011).
Figure 1. Viral meningitis notifications between 31/Jul/2011 and 02/Aug/2012 (n=267)
Data source: CIDR (data as of 02/Aug/2012)
During the time period under investigation (week 31, 2011-02/Aug/2012), enterovirus was detected in most cases (199 cases,74.5%); Human Herpes Virus type 6 in 31 cases (11.6%); Herpes Simplex (unspecified, type 1 or type 2) in seven cases (2.6%); Varicella species in three cases (1.1%); echovirus (unspecified or type 6) in three cases (1.1%); and no specific virus was reported for 24 cases (9%). A peak in enterovirus notifications was evident in week 29, 2012 when 12 cases were notified. The number of notifications by week and virus is seen in figure 2.
Figure 2. Notification of viral meningitis cases, by week and virus, between 31/Jul/2011 and 02/Aug/2012 (n=267)
Data source: CIDR (data as of 02/Aug/2012)
During this time period the majority of notifications were in children < 5 years of age (56%) (figure 3), with infants, particularly those less than one month of age most commonly notified (figure 4).
Figure 3. Viral meningitis notifications by age group, between 31/Jul/2011 and 02/Aug/2012 (n=267)
Data source: CIDR (data as of 02/Aug/2012)
Figure 4. Viral meningitis notifications by age group (months and years), between 31/Jul/2011 and 02/Aug/2012 (n=267)
Data source: CIDR (data as of 02/Aug/2012)
Notifications of viral meningitis have been made in all HSE areas, but the majority of cases have been notified from the HSE East (n=156, 58%).
Discussion
During the past year all ages have been affected by an increase in viral meningitis. But infants, particularly those younger than six months of age, have been most affected.
Although most people can become infected with enterovirus only a minority will develop meningitis. Enterovirus infection can spread readily from person to person via the faecal-oral route (virus shedding can continue for several weeks after infection). These viruses can also be spread through respiratory secretions (saliva, sputum, or nasal mucus) of an infected person. Good personal hygiene is therefore important. Emphasis is put on hand hygiene, particularly after using the toilet, before preparing or eating food, after contact with someone who has viral meningitis or a similar illness, and after changing or handling dirty nappies.
Meningitis infection typically presents with sudden onset of fever, headache, and stiff neck. Nausea, vomiting, photophobia (sensitivity to light) and altered mental status may also occur. In infants viral meningitis may present with irritability, poor eating and difficulty in waking the child. Patients presenting with symptoms of meningitis should be seen by their GP and referral to hospital particularly for children is usual in order to out-rule bacterial meningitis. For older individuals referral to hospital is made based on clinical presentation and severity of symptoms.
There is no specific treatment for viral meningitis. However, most patients completely recover without treatement within 7 to 10 days.
As enterovirus is the most common form of viral meningitis the following preventive measures should be followed to prevent or minimise spread of these viruses:
Hand hygiene - Wash hands thoroughly and often, especially after changing nappies, using the toilet, or coughing or blowing your nose.
Clean contaminated surfaces with soap and water and then disinfect them with a dilute solution of chlorine-containing bleach.
Avoid kissing or sharing eating or drinking containers with sick people or with others when you are sick.
Suzanne Cotter, Piaras O'Lorcain, HPSC
Increase in enteroviral viral meningitis, 2011-2012
Viral meningitis is relatively common and is usually caused by enterovirus infections. In temperate climates, such as Ireland, enterovirus meningitis occurs mainly in late summer, and is most frequent in preschool children. Transmission usually occurs through the faecal-oral route, but may also occur via the respiratory route or contact with a contaminated environment. The incubation period is usually 3-6 days.
The typical presentation includes headache, fever, nausea or vomiting, and occasionally a rash. A history of a sore throat or diarrhoea may precede meningitis symptoms. The majority of infections cause mild or inapparent disease, but severe cases may be hospitalised for diagnosis and management of symptoms. There is no specific drug treatment for most cases of viral meningitis. Recovery is usually complete and rapid. Death caused by viral meningitis is extremely rare. Recently, death was reported in two viral meningitis cases: one in December 2011 where the cause of death was not due to the infection itself, and another in July 2012 where the cause of death was not specified, both occurring in children less than two years of age.
Diagnosis of viral meningitis is based on clinical presentation, cerebrospinal fluid (CSF) findings and detection of a viral pathogen in a CSF, faecal or throat sample. Since November 2005 the National Virus Reference Laboratory (NVRL) has been routinely doing PCR testing for enteroviruses on CSF samples received.
In recent years an increase in the number of viral meningitis notifications made to HPSC is notable with a substantial increase in numbers notified in 2012.
Methods
Annual notifications of viral meningitis between week 1, 2004 and week 31, 2012 were extracted from CIDR. Detailed analysis on notifications during the 12-month period between week 31, 2011 and 02/Aug/2012 was also done using MS Excel. Data presented here are provisional.
Results
Overall, there has been an increase in viral meningitis notifications since 2006, apart from 2007 when relatively few cases (n=45) were reported in comparison to other years during this time period (figure 1). Seasonality is evident with most notifications during summer months. Since May 2011 an increase in monthly notifications is evident with 267 notifications between week 31, 2011 and 02/Aug/2012 compared to 186 for the similar time period in the previous year (August 2010-July 2011).
Figure 1. Viral meningitis notifications between 31/Jul/2011 and 02/Aug/2012 (n=267)
Data source: CIDR (data as of 02/Aug/2012)
During the time period under investigation (week 31, 2011-02/Aug/2012), enterovirus was detected in most cases (199 cases,74.5%); Human Herpes Virus type 6 in 31 cases (11.6%); Herpes Simplex (unspecified, type 1 or type 2) in seven cases (2.6%); Varicella species in three cases (1.1%); echovirus (unspecified or type 6) in three cases (1.1%); and no specific virus was reported for 24 cases (9%). A peak in enterovirus notifications was evident in week 29, 2012 when 12 cases were notified. The number of notifications by week and virus is seen in figure 2.
Figure 2. Notification of viral meningitis cases, by week and virus, between 31/Jul/2011 and 02/Aug/2012 (n=267)
Data source: CIDR (data as of 02/Aug/2012)
During this time period the majority of notifications were in children < 5 years of age (56%) (figure 3), with infants, particularly those less than one month of age most commonly notified (figure 4).
Figure 3. Viral meningitis notifications by age group, between 31/Jul/2011 and 02/Aug/2012 (n=267)
Data source: CIDR (data as of 02/Aug/2012)
Figure 4. Viral meningitis notifications by age group (months and years), between 31/Jul/2011 and 02/Aug/2012 (n=267)
Data source: CIDR (data as of 02/Aug/2012)
Notifications of viral meningitis have been made in all HSE areas, but the majority of cases have been notified from the HSE East (n=156, 58%).
Discussion
During the past year all ages have been affected by an increase in viral meningitis. But infants, particularly those younger than six months of age, have been most affected.
Although most people can become infected with enterovirus only a minority will develop meningitis. Enterovirus infection can spread readily from person to person via the faecal-oral route (virus shedding can continue for several weeks after infection). These viruses can also be spread through respiratory secretions (saliva, sputum, or nasal mucus) of an infected person. Good personal hygiene is therefore important. Emphasis is put on hand hygiene, particularly after using the toilet, before preparing or eating food, after contact with someone who has viral meningitis or a similar illness, and after changing or handling dirty nappies.
Meningitis infection typically presents with sudden onset of fever, headache, and stiff neck. Nausea, vomiting, photophobia (sensitivity to light) and altered mental status may also occur. In infants viral meningitis may present with irritability, poor eating and difficulty in waking the child. Patients presenting with symptoms of meningitis should be seen by their GP and referral to hospital particularly for children is usual in order to out-rule bacterial meningitis. For older individuals referral to hospital is made based on clinical presentation and severity of symptoms.
There is no specific treatment for viral meningitis. However, most patients completely recover without treatement within 7 to 10 days.
As enterovirus is the most common form of viral meningitis the following preventive measures should be followed to prevent or minimise spread of these viruses:
Hand hygiene - Wash hands thoroughly and often, especially after changing nappies, using the toilet, or coughing or blowing your nose.
Clean contaminated surfaces with soap and water and then disinfect them with a dilute solution of chlorine-containing bleach.
Avoid kissing or sharing eating or drinking containers with sick people or with others when you are sick.
Suzanne Cotter, Piaras O'Lorcain, HPSC