Sally Furniss
Well-known member
Vigilance for measles and pertussis during the novel influenza A (H1N1) pandemic
The syndrome of influenza-like illness (ILI) is most prominent during the influenza season and is defined as a history of fever, chills and sweating or a clinically documented fever >38?C plus cough and/or sore throat. At present, there is an intense focus on ILI in the community due to the current novel influenza A (H1N1) pandemic. However, other notifiable diseases can clinically resemble ILI, including pertussis and measles, which are of current public health concern. Therefore, front-line medical practitioners should be on the alert.
Measles is so highly infectious that one case can be considered an outbreak. Given that the prodromal phase of measles can be non-specific (fever, coryza, cough and conjunctivitis) and the infectious period can begin 1 to 2 days prior to the prodrome (3 to 5 days prior to the onset of rash), a case of measles initially missed can result in major contact tracing efforts by public health to control the outbreak. Recent large outbreaks of measles have been seen both nationally and overseas including Australia, the United Kingdom, as well as parts of central Europe, Africa and Asia. The current outbreak in Christchurch has included over 100 cases over June and July this year (in comparison, there was a total of 12 measles cases for the entire country in 2008). The less than optimal Measles Mumps Rubella (MMR) immunisation coverage nationally (86% for first dose of MMR by 24 months)1 and the infectivity of measles is likely to result in increasing cases arising from national or overseas outbreaks.
Like measles, pertussis is highly infectious, and cases require a public health response in an effort to contain the transmission of infection, particularly in high risk occupational and patient groups. While the paroxysmal stage of pertussis can clinically lead to an appropriate diagnosis, patients with pertussis are actually most infectious during the non-specific initial catarrhal stage, which consists of rhinorrhoea and cough. This year, pertussis figures have been closely monitored as numbers of cases have markedly increased throughout New Zealand. For example, in the Auckland region there were 26 cases of pertussis during June 2009, compared to 5 cases for the same month last year. This is of particular concern as epidemics of pertussis tend to occur every 3 to 4 years, and the last epidemic of pertussis in New Zealand occurred during 2004 and 2005.
Immunisation is the most effective method of prevention against pertussis and measles infection. Timely vaccination will prevent severe infection and infant death associated with pertussis, while ensuring that children receive both MMR doses enables better immunity, as only 90% to 95% of vaccine recipients seroconvert after one dose of MMR2
Certain clinical features associated with measles and pertussis, as well as other notifiable diseases such as meningococcal disease and group A Streptococcus tonsillopharyngitis (leading to rheumatic fever) may resemble ILI. Therefore, it is important that these diseases be considered as part of the differential diagnosis, alongside novel influenza A (H1N1), for patients presenting with an ILI syndrome to ensure appropriate investigation, and subsequent diagnosis, treatment and public health management.
For list of references see - www.surv.esr.cri.nz/surveillance/NZPHSR.php
Dr Shanika Perera, Public Health Medicine Specialist, Auckland Regional Public Health Service
http://www.surv.esr.cri.nz/
The syndrome of influenza-like illness (ILI) is most prominent during the influenza season and is defined as a history of fever, chills and sweating or a clinically documented fever >38?C plus cough and/or sore throat. At present, there is an intense focus on ILI in the community due to the current novel influenza A (H1N1) pandemic. However, other notifiable diseases can clinically resemble ILI, including pertussis and measles, which are of current public health concern. Therefore, front-line medical practitioners should be on the alert.
Measles is so highly infectious that one case can be considered an outbreak. Given that the prodromal phase of measles can be non-specific (fever, coryza, cough and conjunctivitis) and the infectious period can begin 1 to 2 days prior to the prodrome (3 to 5 days prior to the onset of rash), a case of measles initially missed can result in major contact tracing efforts by public health to control the outbreak. Recent large outbreaks of measles have been seen both nationally and overseas including Australia, the United Kingdom, as well as parts of central Europe, Africa and Asia. The current outbreak in Christchurch has included over 100 cases over June and July this year (in comparison, there was a total of 12 measles cases for the entire country in 2008). The less than optimal Measles Mumps Rubella (MMR) immunisation coverage nationally (86% for first dose of MMR by 24 months)1 and the infectivity of measles is likely to result in increasing cases arising from national or overseas outbreaks.
Like measles, pertussis is highly infectious, and cases require a public health response in an effort to contain the transmission of infection, particularly in high risk occupational and patient groups. While the paroxysmal stage of pertussis can clinically lead to an appropriate diagnosis, patients with pertussis are actually most infectious during the non-specific initial catarrhal stage, which consists of rhinorrhoea and cough. This year, pertussis figures have been closely monitored as numbers of cases have markedly increased throughout New Zealand. For example, in the Auckland region there were 26 cases of pertussis during June 2009, compared to 5 cases for the same month last year. This is of particular concern as epidemics of pertussis tend to occur every 3 to 4 years, and the last epidemic of pertussis in New Zealand occurred during 2004 and 2005.
Immunisation is the most effective method of prevention against pertussis and measles infection. Timely vaccination will prevent severe infection and infant death associated with pertussis, while ensuring that children receive both MMR doses enables better immunity, as only 90% to 95% of vaccine recipients seroconvert after one dose of MMR2
Certain clinical features associated with measles and pertussis, as well as other notifiable diseases such as meningococcal disease and group A Streptococcus tonsillopharyngitis (leading to rheumatic fever) may resemble ILI. Therefore, it is important that these diseases be considered as part of the differential diagnosis, alongside novel influenza A (H1N1), for patients presenting with an ILI syndrome to ensure appropriate investigation, and subsequent diagnosis, treatment and public health management.
For list of references see - www.surv.esr.cri.nz/surveillance/NZPHSR.php
Dr Shanika Perera, Public Health Medicine Specialist, Auckland Regional Public Health Service
http://www.surv.esr.cri.nz/