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Volume 3 No 16; 24 April 2009

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• Malaria imported into the United Kingdom in 2008: implications for those advising travellers
  
  
• Radon in dwellings in Scotland: 2008 Review and Atlas
  
  

Malaria imported into the United Kingdom in 2008: implications for those advising travellers

Recently published data on cases of malaria reported to the Health Protection Agency (HPA) Malaria Reference Laboratory in 2008 [1] show that travellers visiting friends and family abroad, particularly in Nigeria and Ghana, continue to be the most likely group of United Kingdom (UK) residents to acquire the infection. Data ­on malaria imported into the UK in recent years are summarised below; they indicate that the potentially fatal disease, although almost completely preventable, remains a significant issue for UK travellers. Details of methods of data collection for malaria have been published elsewhere [2].

Figure 1. Cases of malaria in the United Kingdom: 1989 to 2008.

There were 1370 cases of malaria reported in 2008, a slight decline on the 1548 cases reported in 2007 and 1758 cases of malaria reported in 2006. It is possible that a few cases have still to be reported. This may be random variation, but there is evidence of a recent decline in malaria transmission in some malaria-endemic countries visited by travellers, in both West and East Africa, which could have an impact on UK imported cases [3, 4].

Over 70% of malaria cases are caused by (the potentially fatal) Plasmodium falciparum and this high proportion of falciparum malaria has been sustained over many years, reflecting the fact most malaria imported to the UK is acquired in Africa. The breakdown of malaria cases reported by region of travel and parasite species is shown in table 1.

Table 1. Cases of malaria by species of parasite and primary region of travel, United Kingdom: 2008

Geographic Area	P.falci-parum.	P. vivax	P. malariae	P. ovale	Pf/Pv	Pf/Pm	Pf/Po	P. sp unspfd	Total	2007
West Africa	763	1	10	38	-	3	3	-	818	808
East Africa	73	10	5	7	-	-	-	-	95	123
Southern Africa	27	2	-	4	-	-	-	-	33	34
Central Africa	23	-	-	6	-	-	-	-	29	27
North Africa	-	-	-	-	-	-	-	-	-	-
Africa - unspec.	20	-	-	5	-	-	-	-	25	14
Asia	8	118	-	-	1	-	-	-	127	194
Far East/SE Asia	1	3	-	-	1	-	-	-	5	5
Oceania	-	10	-	-	1	-	-	-	11	15
Central/S. America	-	3	-	-	-	-	-	-	3	14
Middle East	1	-	-	-	-	-	-	-	1	1
Not given	171	30	5	16	-	-	-	1	223	313
Total	1087	177	20	76	3	3	3	1	1370	1548

Six deaths from malaria in 2008 have been reported to date, one of uncertain origin, the rest from Africa. Vivax malaria deaths are rare, and are often associated with co-morbidity. There is a small variation in the number of deaths from malaria in the UK every year but the number for 2008 is broadly similar to the annual average since 2000 (nine).

Among patients with malaria where the history of prophylaxis was obtained, 668/809 (83%) had not taken prophylaxis, and a high proportion of the remainder took prophylaxis not recommended for their travel destination by the HPA Advisory Committee on Malaria Prevention in UK Travellers (ACMP). This high proportion is very similar to recent years. Some groups are at particular risk of acquiring malaria and are not being reached by health messages about the importance of antimalarial prophylaxis. Of those who had malaria diagnosed in the UK, where ethnicity was known, 129 were reported as white British, compared with 924 who were reported as African or of African descent and 131 reported as south Asian or of south Asian decent. The overall trend has been for the proportion of malaria in those of south Asian descent to decrease markedly due to a reduction in malaria imported from South Asia (especially vivax malaria), while the proportion in those of African descent has increased over time. The burden of falciparum malaria in particular falls heavily on those of African ethnicity [2,3]. These trends have been explored in more detail in other recent HPA publications [5,6].

Among cases who were travellers from the UK (rather than normally resident in an endemic area), where reason for travel was known, 552/716 (77%) were visiting friends and relatives (table 2), an almost identical proportion to previous years. The ratio of malaria in UK residents visiting friends and relatives compared with malaria cases acquired in holiday travellers was around 7:1; this group presents the greatest public health challenge [6]. As with all routinely collected data, exact figures should be treated with caution. It seems likely that those travelling to visit friends and relatives are either not seeking or not able to access medical advice on malaria prevention before they travel, or they are not being given good advice, or they are not adhering to it; they may not perceive themselves to be at risk because the destination is familiar to them. Probably all these factors contribute. Targeting these groups, and their healthcare providers, should be considered a priority.

Table 2. Cases of malaria by stated reason for travel, UK: 2008

Population group	P.f.	P.v.	P.m.	P.o.	Pf/Pv	Pf/Pm	Pf/Po	P. sp unspfd	Total
Visiting family in country of origin	460	60	7	21	1	2	1	-	552
Holiday travel	55	17	3	3	-	1	-	-	79
Foreign visitor ill while in UK	71	12	2	3	-	-	-	-	88
New entrant	37	13	1	7	-	-	1	-	59
Business/professional travel	35	9	-	3	1	-	-	-	48
UK citizen living abroad	17	6	1	3	1	-	-	-	28
Foreign student studying in UK	16	6	-	3	-	-	1	-	26
Civilian sea/air crew	6	-	-	-	-	-	-	-	6
Children visiting parents living abroad	1	-	-	-	-	-	-	-	1
Other	1	-	-	-	-	-	-	-	1
British armed services	-	-	-	1	-	-	-	-	1
Not stated	388	54	6	32	-	-	-	1	481
Total	1087	177	20	76	3	3	3	1	1370

 

These data indicate that malaria, an almost completely preventable disease but one which can be fatal, remains a significant issue for UK travellers. Failure to take prophylaxis is associated with the majority of cases in UK residents travelling to malarial areas. There is continuing evidence that those of African or Asian ethnicity going to visit friends and relatives are at increased risk, and those providing advice should engage with these travellers wherever possible. The ACMP guidelines [7] and resources available from the National Travel Health Network and Centre [8] should assist clinicians in helping travellers to make rational decisions about protection against malaria.

References

1. Imported malaria cases and deaths, United Kingdom: 1989 - 2008: data from the HPA Malaria Reference Laboratory. Available from the Malaria Epidemiological Data pages on the Agency website.

2. Smith AD, Bradley DJ, Smith V, Blaze M, Behrens RH, Chiodini PL , Whitty CJM. Imported malaria and high risk groups: observational study using UK surveillance data 1987-2006. BMJ. 2008; 337: a120. doi: 10.1136/bmj.a120.

3. Bhattarai A, Ali AS, Kachur SP et al. Impact of artemisinin-based combination therapy and insecticide-treated nets on malaria burden in Zanzibar. PLoS Med. 2007 Nov 6; 4(11): e309.

4 . Ceesay SJ, Casals-Pascual C, Erskine J, Anya SE, Duah NO, Fulford AJ, Sesay SS, Abubakar I, Dunyo S, Sey O, Palmer A, Fofana M, Corrah T, Bojang KA, Whittle HC, Greenwood BM, Conway DJ. Changes in malaria indices between 1999 and 2007 in The Gambia: a retrospective analysis. Lancet. 2008; 372: 1545-54.

5. Health Protection Agency. Migrant Health: Infectious diseases in non-UK born populations in England, Wales and Northern Ireland. A baseline report 2006. London: Health Protection Agency Centre for Infections. 2006. Available at:http://www.hpa.org.uk/webw/HPAweb&HPAwebStandard/HPAweb_C/1201767921328?p=1158945066450.

6. Health Protection Agency. Foreign travel-associated illness - a focus on those visiting friends and relatives, 2008 report. London: HPA, 2008. Available at: http://www.hpa.org.uk/web/HPAwebFile/HPAweb_C/1231419800356.

7. Chiodini P, Hill D, Lalloo D, Lea G, Walker E, Whitty CJM and Bannister B. Guidelines for malaria prevention in travellers from the United Kingdom. London, Health Protection Agency, January 2007. Available at: http://www.hpa.org.uk/webw/HPAweb&HPAwebStandard/HPAweb_C/1195733823080?p=1191942128258.

8. http://www.nathnac.org/.

Radon in dwellings in Scotland: 2008 Review and Atlas

A Scottish Government-funded, Health Protection Agency report [1] has provided the first radon "probability map" for the whole of Scotland, identifying a number of Radon Affected Areas (RAA) where there is a more than 1% probability of the naturally-occurring radon level being above the Action Level [2] above which it is recommended that remedial measures be taken.

The Scottish Government has announced a programme of help, advice and training, including free radon tests, for householders in areas with a five or more percent chance of the radon Action Level being exceeded.

Measurements were taken in a representative sample of dwellings (more than 19,000) across the whole country, including the western and northern isles, for the purposes of the mapping exercise. The areas with the highest number of possibly affected homes include Aberdeenshire, Highland, Orkney and the Scottish Borders. However, out of a total of 62,000 dwellings in RAAs, it is estimated that only 1-3,000 will show radon levels above the Action Level.

The Agency report presents the data from the radon measurements including maps showing the location of RAAs in relation to council boundaries, settlements and major roads, and broken down by local authority and by various divisions of the postcode system.

The Scottish Government will be working with the Agency and others to offer information and advice in the areas most affected by radon. The Scottish Government's free testing programme, which will be carried out by the Agency, has the twin objectives of identifying particular homes with high radon levels and encouraging owners and landlords to reduce such levels [3].

An equivalent Agency report for England and Wales was published in 2007 [4] and recommendations for UK dwellings made last year [5].

References

1. Green BMR, Miles JCH and Rees DM. HPA-RPD-051. Radon dwellings in Scotland: 2008 Review and Atlas. HPA Centre for Radiation, Chemical and Environmental Hazards (Radiation Protection Division), April 2009. ISBN 978-0-85951-634-1. Printed copy, £21.00 + 10% postage and packing, available from CRCE Information Office (tel: 01235 822742, email: chiltoninformationoffice@hpa.org.uk). Available via the Radiation Reports pages on the Agency website.

2. The UK Action Level for radon is 200 becquerels per cubic metre. Further information is available via the Radiation A-Z topics menu on the Agency website.

3. "Radon map published", Scottish Government press release, 23 April 2009. Available at: http://www.scotland.gov.uk/News/Releases/2009/04/23101833.

4. Miles JCH, Appleton JD, Rees DM, Green BMR, Adlam KAM, Myers AH. Indicative Atlas of Radon in England and Wales HPA-RPD-033. Health Protection Agency, 2007. ISBN 978-0-85951-608-2.. Available at: http://www.hpa.org.uk/webw/HPAweb&HPAwebStandard/HPAweb_C/1204186222060?p=1197637096018.

5. "HPA Board gives advice on radon measures for new homes", HPA press release, 21 May 2008, http://www.hpa.org.uk/webw/HPAweb&HPAwebStandard/HPAweb_C/1211354081428?p=1204186170287.