News Archives |
Volume 3 No 9; 6 March 2009
- Increase in reported cases of wound botulism associated with injecting drug use in Southern England
- Confirmed avian influenza H6N1 in two poultry farms in the East of England
Increase in reported cases of wound botulism associated with injecting drug use in Southern England
Following an unusual recent increase in reported cases of wound botulism among injecting drug users, clinicians are being encouraged not to delay treatment with antitoxin where the infection is definitely suspected.
Six cases of clinically diagnosed wound botulism among IDUs have been reported to the Health Protection Agency Centre for Infections (CfI) since 11 January 2009. These cases – aged between 30 and 60 years old, with five being male – have been reported from London, East of England and South East regions. All the cases reported injecting heroin. Clostridium botulinum Type B was laboratory confirmed in three of the cases and C. botulinum Type A in one of the cases.
Wound botulism may be caused by injecting heroin contaminated with C. botulinum. Wound botulism in injecting drug users is now the most common presentation of the infection seen in the UK. Whereas no cases of wound botulism had been reported among IDUs in the United Kingdom before 2000, by the end of 2007 a total of 146 suspected cases had been reported. The rate of reporting fell in subsequent years compared with the early part of the decade, only four cases being reported in 2008 (only one laboratory confirmed) from across England and Wales [1].
However, there was a recent cluster of six wound botulism cases among IDUs in Dublin, Republic of Ireland, during November and December 2008 [2] and clusters have also been reported from a number of other countries over the last decade [3-7].
Earlier this year there was also a fatal case of Clostridium novyi in the South East region. A 39 year old male was admitted to hospital on 30 January 2009 with a perineal abscess and died on 1 February. He had injected heroin into the perineum. Clostridium novyi Type A was isolated from a sample obtained from pus in the abscess. There has also been a recent cluster of cases of necrotising fasciitis in IDUs in Lanarkshire, Scotland [8].
Wound botulism occurs when spores of Clostridium botulinum contaminate a wound, germinate and produce botulinum neurotoxin in vivo. The symptoms of botulism are caused by the neurotoxin, which blocks the release of acetycholine at the neuromuscular junction resulting in a descending flaccid paralysis. Patients with botulism 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 respiratory muscles. If onset is very rapid, there may be no symptoms before sudden respiratory paralysis occurs.
Clinicians should suspect botulism in any patient with an afebrile, descending, flaccid paralysis and specialist advice should be urgently sought from an Infectious Diseases Physician.
Botulinum antitoxin is effective in reducing the severity of symptoms if administered early in the course of the disease. C. botulinum is sensitive to benzyl penicillin and metronidazole. In cases of wound infection, antimicrobial therapy and surgical debridement should reduce the organism load and therefore toxin production, but circulating toxin can only be neutralised by the early administration of antitoxin.
Where there is definite clinical suspicion of botulism, treatment with antitoxin should not be delayed for microbiological testing.
Further general information about wound botulism cases in IDUs can be found on the HPA website [9].
References
1. HPA. Wound botulism suspected cases reported to the Health Protection Agency Centre for Infections, England and Wales: 2000-2007. HPA website [online]. www.hpa.org.uk/webw/HPAweb&HPAwebStandard/HPAweb_C/1195733759064?p=1191942152234.
2. Barry J, Ward M, Cotter S, MacDiarmada J, Hannan M, Sweeney B et al. Botulism in injecting drug users, Dublin, Ireland, November-December 2008 . Euro Surveill 2009 14(1), 8 January 2009. Available at: www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19082.
3. Davis LE, King MK. Wound botulism from heroin skin popping. Curr Neurol Neurosci Rep. 2008; 8(6): 462-8.
4. ECDC. Wound botulism in Switzerland. Burnens A. Euro Surveill 1999; 3(9): pii=1447. Available at: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=1447.
5. ECDC. Cases of wound botulism in Switzerland. Burnens A. Euro Surveill 2000; 4(5): pii=1666. Available at: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=1666.
6. ECDC. Hasseltvedt V and Aavitsland P. Botulism in Norway. Kuusi M. Euro Surveill. 1999; 4(1): pii=44. Available at: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=44.
7. ECDC. Outbreak of wound botulism in injecting drug users in Germany, October-December 2005. Alpers K, van Treeck U and Frank C. Euro Surveill. 2005;10(50):pii=2859. Available at: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=2859.
8. Health Protection Scotland. Necrotising fasciitis in persons who have injected drugs, HPS Weekly Report 2009; 43(1): current note, 7 January 2009.
9. HPA. Wound botulism cases in injecting drug users. HPA website [online].
Confirmed avian influenza H6N1 in two poultry farms in the East of England
The Department for the Environment Food and Rural Affairs (Defra) identified infection with an avian influenza virus in poultry on two premises in the East of England on 26 February 2009 [1] but could not initially classify the subtype; this was later identified as H6N1 on 27 February. It has been identified as being of low pathogenicity in poultry as have all H6 subtypes previously detected.
The H6 virus type has been isolated in domestic poultry and wild birds in Europe over the last few years. The virus normally causes asymptomatic infections in waterfowl but in chickens has been associated with reduced egg production, upper respiratory tract infection (URTI) and increased mortality. There are no case reports of illness in humans associated with naturally acquired H6 infection; however the virus can cause mild URTI when artificially inoculated in volunteers [2] and H6 antibodies have been detected in US vets and poultry workers in southern China [3,4]. There are no recorded instances of human-to-human transmission [5].
A risk assessment determined that the current level of risk to humans from H6N1 avian influenza was low and that post exposure prophylaxis with oseltamivir was not indicated. Nonetheless, exposure to any avian influenza virus should be minimised and the HPA has advised that personal protective equipment should be worn by workers in contact with the birds.
Norfolk Suffolk and Cambridgeshire Health Protection Unit identified 27 people that had been exposed to the birds. These individuals were given advice and information and offered seasonal influenza vaccination, as appropriate. Health monitoring for all those exposed is being undertaken and this will continue for seven days after last contact with infected birds. In addition, specimens for serology have been collected from 22 of the 27 exposed individuals, to assess any serological response to this new subtype. Follow up samples will be taken after 21-28 days.
Health surveillance identified three reported cases of symptomatic illness in the exposed group. One case had mild eye and throat irritation but no flu like symptoms; eye and throat swabs were negative. One case reported a six day history of sore throat and symptoms of coryza; these were resolving and serological and virological swabs were taken. One case reported sore throat and symptoms of coryza on 2 March. The case was started on oseltamivir, which was discontinued following negative virology results.
References
1. Defra Information Bulletin [online], 26 February 2009. Available at: http://www.defra.gov.uk/news/latest/2009/animal-0226a.htm.
2. Beare AS, Webster RG. Replication of avian influenza viruses in humans. Archives of Virology 1991; 119 (1-2): 37-42.
3. Myers FP, Setterquist SF, Capuano AW, Gray GC. Infection due to three avian influenza subtypes in United States veterinarians. Clin Infect Dis 2007; 45 (1): 1, 4-9.
4. Shortridge KF. Pandemic influenza a zoonosis? Semin Resp Infect 1992; 7 (1); 11-25.
5. Subbarao K and Katz J. Avian influenza viruses infecting humans. Cell. Mol. Life Sci 2000; 57 (12): 1770-1784.