Infections

Malaria - Spotting the Unusual

Approximately 1,750 cases of malaria are imported into the UK by people returning from visits abroad each year and between five and 15 of these prove fatal. But malaria can be avoided by taking anti-malarial medication and following other preventive advice.

The Health Protection Agency's Malaria Reference Laboratory (MRL) is responsible for confirming infection with malaria, identifying the species of malaria responsible, and monitoring trends. It works closely with the Travel and Migrant Health Section (TMHS) of the Centre for Infections which collates national information and reporting on a range of travel associated infections.

 

As part of the Agency's enhanced surveillance work, the MRL sends a patient report form to the doctor treating the patient to gather detailed information about the case. Information is stored on a database enabling the team to identify any links between cases.

In early December 2005, the Agency became aware that higher than usual numbers of people returning from The Gambia were developing malaria; several people had died and others were being treated in intensive care. The database highlighted further cases; and follow-up by the MRL and TMHS identified that most of the cases had failed to take prophylaxis.

Increasing malaria awareness in travellers became a priority. Within a week, the Agency issued an alert in its Communicable Disease Report (CDR) Weekly which has more than 5,000 subscribers, mostly public health workers from across the UK . The Agency's press office issued information through the media that malaria is a preventable disease but that travellers need to get advice and take the proper precautions.

Following the alerts, the team continued its surveillance and laboratory confirmation and identified more cases. As these appeared, the Agency issued another media release to target the travel trade press.

Between 10 October 2005 and 12 January 2006, there were 27 cases of malaria, including three deaths, in people returning from The Gambia; seven were known to have been treated in intensive care units.

Of the 27 cases, 20 were holiday makers. Information about the use of prophylaxis was available for 25 of the 27 cases: 13 took none, six took inadequate prophylaxis. This highlights the fact that imported malaria in the UK is strongly associated with failure to take malaria prophylaxis.

The coordinated work and expertise of the Agency's staff enabled them to identify quickly and react swiftly to an emerging problem. Further work is underway within the Agency to raise awareness of malaria and its prevention among travellers.

 

Wound Botulism

Botulism is a disease caused by neurotoxins produced by the bacterium Clostridium botulinum . It is common in the environment, including in the soil. There are three naturally occurring forms of this disease in humans: food-borne, intestinal and wound botulism.

The effects of the neurotoxin are similar for all these forms of the disease and results in a descending paralysis which, in the most severe cases, is life threatening.

All forms of botulism are rare in the UK . However, in 2000, staff in the Agency detected wound botulism as an emerging problem. Clinicians working with injecting drug users (IDUs) were recognising C.botulinum wound infections (wound botulism) in this group for the first time.

There are no records in the Agency of wound botulism in the UK prior to the end of 1999. However this disease had been reported in other countries, particularly in patients with traumatic wounds and in injecting drug users.

Surveillance by the Agency identified wound botulism as an emerging problem in the UK : five cases of wound botulism were detected in 2000; a further 24 had occurred by the end of 2002; and an additional 82 cases occurred during 2003/05.

This upsurge has resulted in wound botulism amongst IDUs becoming the most common form of this disease in the UK and since each case requires intensive and prolonged treatment, this represents a considerable cost to the NHS each year.

On becoming aware of the problem, the Agency undertook a series of measures to prevent further disease. It improved laboratory diagnosis and enhanced surveillance to understand better the risk factors for infection.

It also issued information to help medical professionals manage cases and provided advice for IDUs to prevent further harm.

One of the major risk factors for wound botulism among heroin users is the practice of 'skin-popping' and/or 'muscle-popping' (injecting the drug into the skin or muscle). IDUs use acid to prepare drugs for injection. The availability of higher purity heroin results in more acidic solutions being injected, which is likely to causes greater tissue damage and may allow C.botulinum a better chance to establish an infection.

In light of this, advice issued by the Agency to IDUs included: smoke heroin rather than inject it; if injecting, do so intravenously; and use as little citric acid as possible. Finally, if swelling, redness or pain occurs at injection sites, they should seek medical advice immediately.

 

Salmonella

During 2005, the efforts of the Agency's surveillance and multi-agency work to reduce cases of salmonella food poisoning paid off.

In the previous year, investigations by the Agency had identified that the use of imported Spanish eggs by caterers and food outlets was linked to an increase in cases of poisoning with two subtypes of Salmonella Enteritidis.

In response, a national multi-agency Outbreak Control Team was set up, consisting of the Health Protection Agency, the Food Standards Agency, the Department for Environment, Food and Rural Affairs, Health Protection Scotland and National Public Health Service for Wales .

The team produced guidance documents for the catering, healthcare, retail and wholesale sectors, and held discussions with the Spanish Government Agencies and egg producers to improve the quality of Spanish eggs.

In September 2005, the Agency was able to reveal that in the first nine months of the year, these efforts had led to a reduction in the salmonella threat linked to the use of imported Spanish eggs by caterers and food outlets. The incidence of one species of Salmonella Enteritidis declined by 63 per cent compared with 2004 and the incidence of another declined by 30 per cent.

 

Escherichia coli

In the autumn of 2005 the Agency was involved in the investigation of the biggest ever outbreak of the O157 strain of Vero cytotoxin-producing Escherichia coli (VTEC O157) in England and Wales .

The outbreak was initially reported in Rhondda Cynon Taf and Merthyr Tydfil , later spreading to Bridgend and Caerphilly and affecting children at 42 schools. More than 150 people, mostly children, were infected with VTEC O157 in an outbreak associated with school meals across south Wales . One child died as a result of the infection.

Strains from patients and suspected food samples were sent to the Agency's Laboratory of Enteric Pathogens in the Centre for Infections, London .

The team confirmed the subtype of E. coli in 107 cases and five separate food samples.

They used a technique called pulsed field gel electrophoresis (PFGE) in the investigation process. It was essential for ongoing inquiries into the outbreak and showed that the strains from the patients and the food were the same, thereby confirming the food as the source of the infection.

Once Agency researchers had identified the source of infection, meat from a particular butcher's shop, the authorities could enforce measures to stop produce from the establishment entering the food chain and prevent further infections.