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Eurosurveillance Weekly: Thursday 15 June 2000. Volume 4, Issue 24
Contents:
1. Clostridium novyi is likely cause of ‘serious unexplained illness’ as cases continue to be
reported
2. Salmonella infection from terrarium in Sweden
3. Reports on surgical site infections and hospital acquired bacteraemias from the
Nosocomial Infection National Surveillance Scheme
4. Safety of meningitis vaccine
5. Preventing meningococcal disease
6. Regional measles surveillance data in the Americas
7. Male circumcision and HIV infection
Clostridium novyi is likely cause of ‘serious unexplained illness’ as
cases continue to be reported
Evidence from several laboratories suggests that the recent cases of ‘serious unexplained
illness’ among injecting drug users (IDUs) in Britain (1) may have resulted from infection with
the bacterium Clostridium novyi type A. Greater Glasgow Health Board has announced that
bacteria of the Clostridium family have now been isolated from nine IDUs by laboratories in
Glasgow (2). Two of these have been confirmed as Clostridium novyi type A by the Public
Health Laboratory Service Anaerobe Reference Unit and the same bacterium has also been
identified in tissue from a third patient’s tissue by the Centers for Disease Control and
Prevention in Atlanta (2). The remaining six isolates appear to be C. novyi type A but have yet
to be fully identified. The PHLS has confirmed that the strain they isolated produces toxin.
Clinical update: Scotland, 12 June
A total of 42 cases of severe unexplained illness had been identified among IDUs in Scotland
by 12 June 2000 - 18 definite and 24 probable. This represents an increase of seven cases
since the last update (5 June (1)): six of these are probable and one is definite. The definite
case developed symptoms on 24 May and presented to hospital on 6 June. The most recent
probable case presented on 10 June. These figures and the definite and probable categories
are based on a case definition adopted by the incident team when the epidemic began.
A probable case is defined as an IDU who has presented to hospital with an abscess or other
significant inflammation at an injecting site (since 1 April 2000) and has either a severe
inflammatory process (large abscess/extensive cellulitis/extensive oedema) at or around an
injecting site or a severe systemic inflammatory reaction with evidence of multiorgan failure
and a high white cell count. A definite case is an IDU who has both severe local and
systemic inflammatory reactions. To maintain consistency, these definitions are being retained
for the present.
For the purposes of active case finding at an international level, however, another ‘syndromic’
definition, for definite cases only, has been agreed (3):
soft tissue inflammation (abscess, cellulitis, fasciitis, or myositis) at an injecting site, and either
(i) severe systemic toxicity (sustained systolic blood pressure <90 mmHg despite fluid
9
resuscitation) and total peripheral white blood cell count (WBC) >30 x 10 /L; or
(ii) postmortem evidence of a diffuse toxic or infectious process including pleural effusions and
soft tissue oedema or necrosis, in an IDU admitted to a hospital or found dead since 1 April
2000.
Clinical update: England and Wales, 15 June
In England and Wales a total of 20 cases (11 fatal) have been reported. The first case was
admitted to hospital on 24 April and the most recent on 9 June. A review of clinical records
has shown that ten of these cases, all from the North West Region, met the specific case
definition described above (3). In addition, a further case of wound botulism in an IDU in north
east England has been confirmed.
The illness is characterised by extensive localised inflammation and oedema at an injecting
site, often followed by rapid deterioration with circulatory collapse, a clinical course that is
consistent with a toxin-mediated cause. Other abnormal findings have included very high white
blood cell counts (often rising to > 30 x 109/L within a few hours), haemoconcentration,
abnormal clotting, ST segment abnormalities on electrocardiography, and raised creatine
kinase. Doctors should be alerted to the speed with which cases can deteriorate and the need
for rapid assessment and treatment (3).
References:
1.
2.
3.
Greater Glasgow Health Board. Likely cause of injector outbreak in Glasgow identified. Press release, 15 June
2000. (http://www.show.scot.nhs.uk/gghb/homepage/)
Greater Glasgow Health Board, Scottish Centre for Infection and Environmental Health. Serious unexplained
illness among injecting drug users in Scotland and the Republic of Ireland – update. Eurosurveillance Weekly
2000; 4: 000608 (http://www.eurosurv.org/2000/000608.htm)
Unexplained illness and death among injecting drug users-Glasgow, Scotland; Dublin, Ireland; and England,
April-June 2000. MMWR Morb Mortal Wkly Rep 2000; 49: 489-92.
(ftp://ftp.cdc.gov/pub/Publications/mmwr/wk/mm4922.pdf)
Reported by Greater Glasgow Health Board and Scottish Centre for Infection and
Environmental Health, Glasgow, Scotland; and Tamara Djuretic ([email protected]),
PHLS Communicable Disease Surveillance Centre, London, England.
Salmonella infection from terrarium in Sweden
When a family in southern Sweden moved house in February 2000 they used an empty
terrarium, usually occupied by two pythons, to keep their 1 year old son out of the way of the
removal men (1). A few days later the child developed gastroenteritis, as did his 17 year old
uncle, who had reassembled the terrarium after the move. Neither of them developed invasive
disease or had to be admitted to hospital. Faecal specimens from both yielded salmonella
subspecies 1. The rest of the family remained well. The snakes had been bought a few years
earlier from a local pet shop. In 1997 three cases of salmonella subspecies 1 infection were
linked to snakes from the same shop.
Snakes, lizards, and turtles have become an important source of human salmonellosis in
recent years. Over 13% of cases of salmonellosis acquired in Sweden in 1996 (80 cases)
were linked to such reptiles. The number of cases has decreased since then, thanks to
recommendations provided to the public and pet shop owners by the agriculture ministry and
the Swedish Institute for Infectious Disease Control, which were also taken up by the media. In
1999, 43 people were infected – 22 people by turtles, 12 by snakes, and nine by lizards. Most
of the cases were children.
The problem of reptile associated salmonellosis has been recorded in Eurosurveillance
Weekly before (2) and the occurrence of invasive, sometimes fatal, cases in children has
prompted the Centers for Disease Control and Prevention to issue guidelines for its prevention
(3).
References:
1.
2.
Meeuwisse A. Ovanlig salmonellasmittväg hos 1-åring. Smittskydd 2000; (5): 56.
(http://www.smittskyddsinstitutet.se/download/pdf/smi5-00.pdf)
Ward L. Fatal neonatal Salmonella rubislaw infection in household with pet reptile in England. Eurosurveillance
Weekly 2000; 4: 000210 (http://www.euorusrv.org/000210.htm)
3.
CDC. Reptile-associated salmonellosis – selected states, 1996-1998. MMWR Morb Mortal Wkly Rep 1999; 48:
1009-13. (http://www.cdc.gov/epo/mmwr/preview/mmwrhtml/mm4844a1.htm)
Reported by Karl Ekdahl ([email protected]), Swedish Institute for Infectious Disease
Control, Stockholm, Sweden.
Reports on surgical site infections and hospital acquired bacteraemias
from English Nosocomial Infection National Surveillance Scheme
The Nosocomial Infection National Surveillance Scheme (NINSS) recently issued reports on
the surveillance of surgical site infection and hospital acquired bacteraemia in English
hospitals (1,2). NINSS is a system to monitor hospital acquired infection (HAI) and help
hospitals to reduce their incidence of infection by identifying areas where clinical practice and
infection control procedures may need to be reviewed. The scheme was set up and funded by
England’s Department of Health and the Public Health Laboratory Service (3).
Ninety-six English hospitals in the eight NHS regions took part in surveillance of surgical site
infection between October 1997 and September 19991. Data from 28 407 operations in 12
categories of surgery yielded reports of 1212 infections (4.3%), the incidence of which varied
between hospitals for all surgical categories. Limb amputation and large bowel surgery most
commonly led to infection in the nine surgical categories in which at least 10 hospitals
participate. The more serious deep or organ/space (as opposed to superficial) infections
accounted for at least 25% of surgical site infections in most categories. The incidence of
surgical site infection rose with the number of risk factors from the US National Nosocomial
Infections Surveillance System risk index (health of patient before surgery, duration of
operation, wound class [likelihood of wound contamination during surgery]) for abdominal
hysterectomy, coronary artery bypass grafts, hip prosthesis, large bowel surgery, and vascular
surgery. For knee prosthesis, limb amputation, or open reduction of a long bone fracture the
trend was less clear. Forty-seven per cent of the pathogens identified as causing infections
were staphylococci: 81% of these were Staphylococcus aureus, 61% of which were resistant
to methicillin (MRSA). MRSA was the commonest cause of surgical site infection in large
bowel and vascular surgery, limb amputation, and open reduction of long bone fractures.
The 61 hospitals that took part in the surveillance of hospital acquired bacteraemia from May
1997 to April 1999 provided information on over a million patients, among whom 3824
episodes of bacteraemia were identified in 3629 patients (3.6 patients per 1000 admissions;
mean of 0.6 bacteraemias per 1000 patient days) (2). Rates of hospital acquired bacteraemia
varied widely between specialties within hospitals, the highest being in general and paediatric
intensive care units (ICUs) and haematology units. Six specialties accounted for 72% of all
bacteraemias: haematology, general ICUs, general medicine, general surgery, geriatric
medicine, and nephrology. Nearly a half of the isolates causing hospital acquired bacteraemia
were staphylococci: 24% were S. aureus, 47% of which were MRSA. More than one organism
was identified in 11% of hospital acquired bacteraemias. Two thirds of bacteraemias whose
source was known were associated with an intravascular device (most commonly central
intravenous catheters) or with other devices, such as urinary catheters or ventilators.
Rates of HAI, stratified by operation type and risk index for surgical site infection and clinical
specialty for hospital acquired bacteraemia, vary between hospitals. This variation within
defined groups of patients provides an opportunity to review and compare clinical and infection
control practice within and between hospitals. NINSS can advise on the interpretation and
further investigation of results for hospitals with higher than average rates. Copies of these
reports and details of the surveillance scheme are available from the Nosocomial Infection
Surveillance Unit, PHLS Central Public Health Laboratory, 61 Colindale Avenue, London NW9
5HT.
References:
1.
Nosocomial Infection National Surveillance Scheme. Surveillance of surgical site infection in English hospitals
1997-1999. London: PHLS, 2000.
2.
3.
Nosocomial Infection National Surveillance Scheme. Surveillance of hospital-acquired bacteraemia in English
hospitals 1997-1999. London: PHLS, 2000.
CDSC. New scheme for surveillance of hospital acquired infections. Commun Dis Rep CDR Wkly 1996; 6: 91,
94. (http://www.phls.co.uk/publications/CDR96/cdr1196.pdf)
Reported by Andrew Pearson, Nosocomial Infection Surveillance Unit, PHLS Central Public
Health Laboratory, London, England. (Adapted from CDR Weekly 2000; 10: 213,6 (16 June).)
Safety of meningitis vaccine
The English Department of Health’s deputy chief medical officer (CMO) issued statements this
week to reassure parents (1) and professionals (Public Health Link CEM/CMO/2000/8) about
the safety of the conjugate vaccine against serogroup C meningococcal disease. The
announcement was made in response to news media reports questioning the safety of the
vaccine.
The deputy CMO offered a reminder that 1530 cases of group C meningococcal meningitis
and septicaemia (150 fatal) had been reported in the United Kingdom (UK) in 1999. Clinical
trials of the group C vaccine in about 8000 infants, children, and young adults in the UK and in
over 20000 in other countries (Canada, Holland, United States) showed that it evoked an
excellent immune response in all age groups (with evidence of long term protection), was well
tolerated, and caused no serious side effects. The vaccine has already reduced the number of
cases of group C meningococcal disease in the age groups targeted for immunisation by
75%2.
Health professionals, encouraged to report all suspected reactions attributable to the new
vaccine, had made 4764 reports by 1 June 2000. Most of the reactions reported were transient
and self limiting. For the first time, reports were accepted on a pilot basis from nursing staff in
addition to doctors, dentists, pharmacists, and coroners. In the context of the 13.5 million
distributed doses, the rate of reported serious suspected adverse reactions is less than 1 in
10000, comparable with that for other immunisation programmes.
The deputy CMO is not planning an urgent review of the immunisation campaign, and said
that the vaccine is undergoing the same rigorous monitoring as any new vaccine and that the
Committee on Safety of Medicines is reviewing the reported suspected adverse reactions, in
line with usual practice. The vaccine is not live and cannot cause meningitis, but it protects
against group C meningococcal disease only – one of several possible causes of meningitis –
and takes some days to give protection. Parents and young people are advised to remain
aware of the signs and symptoms of meningitis but recommended to continue to take up the
opportunity to be immunised (1).
References:
1.
2.
Department of Health. Safety of the meningitis C vaccine programme. Press statement, 12 June 2000.
(2000/0347)
<http://pipe.ccta.gov.uk/coi/coipress.nsf/70e1fa6684c1d3f380256735005750fb/66bba0534f883736802568fc005
142c5? OpenDocument>.
CDSC. Meningococcal disease falls in vaccine recipients. Commun Dis Rep CDR Wkly 2000; 10: 133,6.
(http://www.phls.co.uk/publications/CDR00/cdr1500.pdf)
Reported by Stuart Handysides ([email protected]), PHLS Communicable Disease
Surveillance Centre, London, England. (Adapted from CDR Weekly 2000; 10: 213,6 (16
June).)
Preventing meningococcal disease
The findings of one of the studies on the basis of which the British government decided to
introduce a programme of immunisation with meningococcal C conjugate vaccine (1) was
published in JAMA last week (2). The study, a randomised controlled trial, showed that
meningococcal C conjugate vaccine is safe and immunogenic, and results in immunological
memory when given with other routinely administered vaccines to infants aged 2, 3, and 4
months.
The participants, 182 infants from Oxfordshire (UK), were randomly assigned to receive
vaccination with one of two lots of meningococcal C conjugate vaccine (groups 1 and 2, n=60
in each) or hepatitis B control vaccine (group 3, n=62), administered with routine
immunisations at 2, 3, and 4 months of age. Boosters were given at 12 months of age. About
half of each group received meningococcal C conjugate vaccine and half plain meningococcal
polysaccharide vaccine.
Serum immunoglobulin G to meningococcal C polysaccharide measured by enzyme linked
immunosorbent assay and serum bactericidal activity were significantly higher in those given
meningococcal C conjugate vaccine than in controls after primary immunisation, and
significantly greater increases in titres followed booster immunisation among those who had
received group C vaccine before than among controls, indicating immunological memory.
An accompanying editorial (3) points out that, although meningococcal conjugate vaccines
offer advantages over their polysaccharide predecessors, numerous challenges will have to be
overcome before improved prevention of meningococcal disease occurs – for example,
variability in the distribution of serogroups by country and continent and age group; and the
ability of N. meningitidis to switch from one serogroup to another through genetic
transformation. These factors identify a need for the development and availability of
multivalent meningococcal conjugates as standalone vaccines and in combination with other
antigens. On the basis of current understanding of N. meningitidis, the broadest possible
approach – a vaccine that includes the conjugated polysaccharides of serogroups A, C, Y, and
W-135 – may be the best choice.
References:
1.
2.
3.
Handysides S. Vaccination programme for group C meningococcal infection is launched. Eurosurveillance
Weekly 1999; 3: 990722. (http://www.eurosurv.org/1999/990722.html#4)
MacLennan JM, Shackley F, Heath PT, Deeks JJ, Flamank C, Herbert M. Safety, immunogenicity, and
induction of immunologic memory by a serogroup C meningococcal conjugate vaccine in infants. JAMA 2000;
283: 2795-801. (http://jama.ama-assn.org/issues/v283n21/full/joc91720.html)
Perkins BA. New opportunities for prevention of meningococcal disease. JAMA 2000; 283: 2842-5.
(http://jama.ama-assn.org/issues/v283n21/full/jed00039.html)
Reported by Birte Twisselmann ([email protected]), PHLS Communicable
Disease Surveillance Centre, London, England.
Regional measles surveillance data in the Americas
In 1994 the ministers of health of the WHO American region established the goal of
eradicating measles virus from the western hemisphere by 2000. To this end, the Pan
American Health Organization (PAHO) developed an improved measles vaccination strategy.
A review of surveillance data for 1996-99 published in the Lancet found that PAHO’s measles
eradication strategy has been effective in interrupting transmission and maintaining the
absence of measles virus circulation in most parts of the Americas (1).
PAHO’s measles eradication strategy has evolved into three principal components: a catch up
measles vaccination campaign targeting all children aged 1 to 14 years, maintaining high
vaccination coverage, (at least 90% in each successive birth cohort), and periodic follow up
measles vaccination campaigns, targeting children aged 1 to 5 years, to prevent the number
of children of preschool age who are susceptible to measles from reaching levels that would
increase the risk of a measles outbreak.
Both the catch up and the follow up campaigns achieved high vaccination coverage in the
respected targeted age groups. In 1996, 2109 confirmed measles cases were reported in the
Americas. A resurgence of measles occurred in 1997, with an outbreak of over 42 000 cases,
which occurred mainly among unvaccinated young adults in Sao Paulo State, Brazil. By 1998,
the number of reported confirmed measles cases had fallen to 14 474, and this reduction
continued to the end of 1999, when fewer than 3000 cases were confirmed. The PAHO
experience provides strong evidence that measles transmission can be effectively interrupted
in large geographical areas if an appropriate vaccination strategy is fully implemented.
Reference:
1.
Hersh BSS, Tambini G, Nogueira AC, Carrasco P, de Quadros CA. Review of regional measles surveillance
data in the Americas, 1996-99. Lancet 2000; 355; 1943-8.
(http://www.thelancet.com/newlancet/reg/issues/vol355no9219/menu_NOD1.html)
Reported by Birte Twisselmann ([email protected]), PHLS Communicable
Disease Surveillance Centre, London, England.
Male circumcision and HIV infection
Compelling epidemiological evidence from over 40 studies shows that male circumcision
provides significant protection against HIV infection, according to an article in the BMJ (1).
Circumcised men are two to eight times less likely to become infected with HIV, and
circumcision also protects against other sexually transmitted infections, such as syphilis and
gonorrhoea, which make those affected two to five times more likely to become infected with
HIV.
Between 75% and 85% of cases of HIV infection worldwide have probably been acquired
during sexual activity. Most cases of primary HIV infection are thought to involve HIV binding
initially to the CD4 and CCR5 receptors found on antigen presenting cells – which include
macrophages, Langerhans’ cells, and dendritic cells – in the genital and rectal mucosa.
Worldwide most men with HIV infection have acquired the virus via the penis. The two most
probable sites for viral entry in primary HIV infection in men are the inner mucosal surface of
the foreskin, which is not keratinised and is rich in Langerhans’ cells, making it particularly
susceptible to the virus, and the frenulum, a common site for trauma and STIs.
Condoms remain the main method for preventing sexual transmission of HIV but are often not
used consistently or correctly, may break during use, and some people have strong cultural or
aesthetic objections to using them. In the light of the evidence presented in the article,
circumcision of males seems highly desirable, especially in countries with a high prevalence of
HIV infection. A programme of neonatal circumcision would not, however, affect HIV
transmission rates for another 15 to 20 years; circumcision at puberty would be the most
immediately effective intervention for reducing HIV transmission. Sexual practices thus far
deemed to be ‘safe’ should also be reconsidered. The development of topically active agents
that could block HIV binding sites and which could be applied to the penis or vagina to create
a ‘chemical condom’ might be more effective and acceptable than any mechanical barrier or
surgical intervention.
Reference:
1. Szabo R, Short RV. How does male circumcision protect against HIV infection. BMJ 2000; 320: 1592-4.
(http://www.bmj.com/cgi/content/full/320/7249/1592)
Reported by Birte Twisselmann ([email protected]), PHLS Communicable
Disease Surveillance Centre, London, England.