• Use of antiviral drugs for influenza

• Wound botulism cases in injecting drug users in the Republic of Ireland

Use of antiviral drugs for influenza

On 12 December 2008 the UK Department of Health issued a letter to NHS staff in England to inform them that the use of antiviral drugs for the treatment or prophylaxis of influenza was now recommended, in line with NICE guidance [1].

The HPA has reviewed the most recent influenza data from a range of clinical, virological and epidemiological surveillance schemes for England. They show an increased level of influenza activity indicating we are now entering a period when there is a substantial likelihood that people presenting with an influenza-like illness are infected with influenza, ie influenza is circulating in the community.

During week 49/2008, the NHS Direct cold/flu and fever calls exceeded baseline levels [2]. The proportion of cold/flu calls increased from 0.9% to 1.2% in week 49/08 (1.2% is the threshold). Fever calls in the 5-14 age-group increased to 10.0% in week 49/08, exceeding the threshold of 9% [3]. The national RCGP national ILI GP consultation rate in week 49 increased sharply to 27.6 consultations per 100 000 GP consultations and is just below the threshold of 30 per 100,000. The threshold is exceeded in central England (37.5) and among 15-44 year olds (32.1). Of the samples referred to the Centre for Infections' Respiratory Virus Unit (RVU) during weeks 48/08 and 49/08, 139 were positive for influenza A, eight A (H1) and 131 A (H3) and two for influenza B. The influenza A viruses characterised so far are well matched to strains contained in the current vaccine. HPA has also received reports of nine outbreaks of influenza-like-illness in various settings across the country, several of which have been confirmed as influenza A.

References

1. National Institute for Health and Clinical Excellence. Oseltamivir, amantadine and zanamivir for the prophylaxis of influenza (including a review of NICE technology appraisal guidance 67). London : National Institute for Health and Clinical Excellence , September 2008. Available at: http://www.nice.org.uk/Guidance/TA158.

2. Cooper DL, Verlander NQ, Elliot AJ, Joseph CA, Smith GE. Can syndromic thresholds provide early warning of national influenza outbreaks? J Public Health (Oxf). 2007 Nov 20: doi 10.1093/pubmed/fdm068.

3. HPA. HPA Weekly National Influenza Report. Published on 10 December, 2008. Available at: http://www.hpa.org.uk/web/HPAwebFile/HPAweb_C/1228894718273.

1. Chief Medical Officer, Professor Sir Liam Donaldson. The influenza immunisation programme 2008/09. London: Department of Health, 31 March 2008, http://www.dh.gov.uk/en/Publicationsandstatistics/Lettersandcirculars/Professionalletters/
Chiefmedicalofficerletters/DH_083812.

2. http://www.immunisation.nhs.uk/Vaccines/Flu/Resources/vaccine_uptake_2008_2009.

Wound botulism cases in injecting drug users in the Republic of Ireland

Botulism is a rare but serious disease with wound botulism being the most common presentation in the UK since 2000. Wound botulism occurs when spores of Clostridium botulinum contaminate a wound, germinate and produce botulinum neurotoxin in vivo. The disease is associated with traumatic wounds and abscesses and has been reported in drug users such as those injecting heroin or sniffing cocaine. Wound infections due to C. botulinum were not recognised in the UK or the Republic of Ireland before 2000 [1]. However, between 2000 and 2007 there were a total of 141 reported cases of wound botulism, all associated with the practice of injecting heroin into muscle or skin.

A cluster of six cases of suspected wound botulism in injecting drug users in Dublin, Ireland, has been reported since the end of November. A patient with symptoms including diplopia, dysarthria and dysphagia and a history of injecting drug use by "skin popping", was admitted to a hospital in Dublin with suspected botulism. Serum from the patient, taken prior to administration of antitoxin, was tested for C. botulinum toxin by the Food Safety Microbiology Laboratory and C. botulinum type B neurotoxin was detected by bioassay; confirming a clinical diagnosis of botulism. The patient was treated with antitoxin and is improving. A further five injecting drug users with suspected wound botulism have presented in Dublin and testing on clinical specimens and a suspected contaminated batch of heroin is on going.

Microbiological testing confirms the clinical diagnosis in around 41% of wound botulism cases either by detection of botulinum neurotoxin in serum or isolation of C. botulinum from wounds. Reasons for the low confirmation rate include timing of specimen collection as once toxin reaches the nerve endings it binds irreversibly; the amount of toxin in the serum being below the level of detection; low volume of serum reducing sensitivity of the test and wound or pus being taken after administration of antimicrobial therapy so organisms may not be viable.

Botulism produces a progressive, symmetrical, descending, flaccid paralysis. Patients may present with blurred vision, drooping eyelids, slurred speech, difficulty swallowing, dry mouth, and muscle weakness. There is usually no fever, no loss of sensation and no loss of awareness. If untreated, paralysis may progress to the arms, legs, trunk, and the respiratory muscles and may lead to death. Clinicians should suspect botulism in any patient with an afebrile, flaccid paralysis. Botulinum antitoxin is effective in reducing the severity of systems if administered early in the course of the disease for all forms of botulism and should not be delayed for the results of microbiological testing. In cases of wound botulism, antimicrobial therapy and surgical debridement are important to reduce the organism load and avoid relapse after antitoxin treatment. C. botulinum is sensitive to benzyl penicillin and metronidazole.

Information on the supply of botulinum antitoxin is available from the Health Protection Agency, Centre for Infections duty doctor on 020 8200 6868 (24 hours). Information on specimen and sample testing can be obtained from Dr Kathie Grant or Vina Mithani at the Food Safety Microbiology Laboratory.

All cases occurred in heroin injectors. Seventy cases occurred in England; the remainder occurred in Scotland (12 cases), Wales (2 cases) and the Republic of Ireland (4 cases). Of the 40 cases in 2004, 36 occurred in England, and of the 12 that were laboratory confirmed, 10 were due to type A. There was some geographical clustering of the cases during 2004, with most cases occurring in London and in the Yorkshire and Humberside region of northeast England.