Current Issue: Volume 16 Number 51	Published on: 21 December 2006	Current Issue in PDF PDF format (283 Kb)

Travel Health

Last updated: 5 October 2006, Volume 16, No. 40 (PDF file, KB) Next update due: January 2007

Travel Health Archives: | 2006 | 2005 | 2004 | 2003 | 2002 | 2001

CDR Home | Infection Reports | Travel Health

Imported infections, England and Wales: April to June 2006

The data presented in this report should be interpreted in conjunction with the report Illness in England, Wales, and Northern Ireland associated with foreign travel – a baseline report to 2002 [1], especially the content under the section ‘Sources of data on travel-associated illness and their limitations for analysis’. Please note that all data presented are provisional and subject to change; the confirmed final data will be presented on a biennial basis.

Of the infections in table 1 that were reported via Co-Surv*, there was a decrease in the second quarter of 2006 of 7.5% (16,103†) compared to the same period in 2005 (17,400). (There may be late reports in 2006 that have yet to be loaded into Labbase2‡ that may account for this.) Travel history reporting has increased from 10.9% in the second quarter of 2005 to 12.9% in the same period in 2006. The actual number of reports associated with recent travel abroad has remained more or less the same (5.9% in 2005 and 6.1% in 2006). Since the quarterly reports began (January 2003), on average, 13.68% of laboratory reports had any travel history recorded, of which 51% stated recent travel (6.8% of the total), with no discernible trend over time (figure 1). Travel history reporting peaks in the summer months coinciding with the time when most United Kingdom (UK) residents travel abroad [2]. The proportion of reports with travel history information remains low, and limits the interpretation of the following data.

Figure 1 Travel history reporting for laboratory reports by quarter, England and Wales: 2003 to June 2006

*provisional data

Table Imported infections in England and Wales: April to June 2006

All data extracted from LabBase2 15 September 2006 unless otherwise specified.

* All data for 2006 is provisional and may be subjected to change

†Data on cholera, S.boydii and S.dysenteriae were supplied by the CfI Laboratory of Enteric Pathogens.

‡Data for malaria were supplied by the HPA Malaria Reference Laboratory and are provisional. Trends are best interpreted on an annual basis.

§Data for Lyme borreliosis and leptospirosis were supplied by the Zoonoses Surveillance Reference Unit, CDSC Wales on behalf of the Leptospira Reference Unit, Hereford and the Lyme Disease Reference Unit, Southampton.

**Data on legionnaires' disease were supplied by the Legionella Section of the Respiratory Diseases Department of CfI.

Gastrointestinal infections

Bacterial infections
In the second quarter of 2006, Salmonella spp (non-typhoidal) were the most frequently reported infections associated with recent travel abroad (578 (24.8%) travel associated cases among 2327 total cases). Of 12,046 reports of Campylobacter spp, 221 (1.8%) were associated with recent travel abroad; the proportions of travel associated reports are consistent with previous quarters. Travel history reporting is usually more complete for Salmonella spp than for Campylobacter spp, with 59.4% of Salmonella spp reports having any information about travel history compared with only 3.7% for Campylobacter spp.

Of the salmonella reports that stated recent travel abroad, Salmonella Enteritidis was the most frequently reported (235 reports), particularly phage type (PT)4 (63 reports) PT1 (56 reports), PT21 (24 reports), and PT14B (21 reports). S. Enteritidis PT1 was most frequently associated with travel to Spain (16 of 56 reports) and PT 4 was most associated with travel to Tunisia and Egypt (14 and 11 of 63 reports respectively). Of all the salmonella reports, 115 reports were associated with travel to north Africa and the middle east (Egypt 40, Tunisia 32, Morocco 16, Turkey 14, and the remainder to nine other countries); 104 reports were associated with travel to Europe (Spain 67, Greece 11, with the remainder to 12 other countries); 102 reports were associated with travel to the Indian sub-continent (India 69, Pakistan 24, and the remainder to three other countries). Other countries of significance were Thailand (39 reports) and Kenya (37 reports); 60 reports had no country of travel stated, and the remainder of salmonella reports were associated with travel to 33 other countries throughout the world.

Of campylobacter reports that stated recent travel abroad, the most frequently reported country of travel was Spain (67/221), followed by India (17), Pakistan (14), Portugal and Turkey (11 each), and Tunisia (nine). Eleven reports had no country stated, and the remainder reported travel to 35 other countries.

In the second quarter of 2006, there were 381 reports of Shigella spp, the organisms that cause dysentery-like (bloody diarrhoea) illness, 168 were due to S. sonnei, 111 were due to S. flexneri, 45 were due to S. boydii, and 14 to S. dysenteriae. Eighteen per cent (69 reports) of all Shigella spp reported recent travel abroad. Nearly half (32/69) were associated with travel to the Indian sub-continent (22 to India, eight to Pakistan, and two to Nepal), 25 were associated with travel to north Africa and the middle east: 16 to Egypt (although one had also travelled to Australia, and another to Greece), four to Iraq, two to Morocco, and one each to Bahrain, Israel, and Tunisia); the remainder had travelled to seven other countries.

There were five reports of Vibrio cholerae O1 in the second quarter of 2006. All were V.cholerae biotype El Tor, of which three were serotype Ogawa (two of which stated travel to India, and one to Morocco), and two were serotype Inaba (both stated travel to India).

There were six reports of Vibrio parahaemolyticus, of which two stated travel to Kenya.

Intestinal protozoal infections
During the second quarter of 2006, there were 576 reports of Cryptosporidium (3.6% with travel history) in England and Wales, of which six (1%) reports stated recent travel abroad. Countries of travel reported via Co-Surv were India, Pakistan (two reports each), Spain, and Guyana (one report each). Sentinel surveillance submission forms to the UK Cryptosporidium Reference Unit (CRU) during the same time frame included 34 (12.1%) travel abroad-related cases. [Rachel Chalmers, Head of UK Cryptosporidium Reference Unit, NPHS Wales, personal communication, 28 September 2006.] Countries of travel reported to CRU were India (five), Pakistan (five), Peru (two), Portugal (two), Egypt (two), and one report each from Australia, Bangladesh, Dominican Republic, Ecuador, Fiji, India and Thailand, Kenya, Nepal, Pakistan and Dubai, South Africa, Spain, Tenerife, and Tunisia; five reports had no country stated. Travel-related Cyptosporidium is under-estimated by routine surveillance.

There were 550 reports of Giardia lamblia (8.2% with travel history), of which 42 had stated recent travel abroad. The most frequently reported region of travel was the ISC (21 reports: 11 to India, eight to Pakistan, and one each to Nepal and Bangladesh) followed by Egypt (four), Mexico (two), Spain (two); country was not stated for four reports and the remainder stated travel to nine other countries.

Other infections reported in this category included 37 reports of Entamoeba histolytica, of which eight stated recent travel abroad. Countries of travel included Kenya, Uganda, Malaysia, Thailand, United States, South Africa, Zambia, and Africa and South America (unspecified countries). Note that some reports had more than one country of travel stated.

There were six reports of Cyclospora spp, of which one stated travel to Thailand; the remainder had no travel history.

Enteric fever
During the second quarter of 2006, there were 55 reports of Salmonella Typhi and 85 reports of Salmonella Paratyphi (82 were S. Paratyphi A of which 21 were PT 13, 14 were PT 1, and 13 were PT 1A; three were S. Paratyphi B). Reports of S. Typhi have decreased by 11.3% compared to the same period in 2005 (62 reports), while the number of S. Paratyphi A reports have increased by 32.3% compared to 2005 (62 reports); this is the second consecutive rise of similar magnitude in this quarter since 2004 (figure 2).

Seventy-seven per cent of all enteric fever reports in the second quarter in 2006 had some information about travel history compared to 71% in the same period in 2005. Of the 55 reports of S. Typhi, 26 (47%) stated recent travel abroad; all but one of these stated travel to the ISC (13 to India, five to Pakistan, three each to Nepal and Bangladesh, and one to Sri Lanka); one report had no country of travel stated. Seventy-nine per cent of S. Paratyphi A reports had travel history information and of those, 53 reports stated recent travel. Pakistan (25 reports) was the most frequently reported country of travel, followed by India (23), and Thailand (one); four reports had no country of travel stated. Of the reports of S. Paratyphi B, one stated travel to Peru and other two had no travel history. There were no reports of S. Paratyphi C during this quarter.

Figure 2 Laboratory reports of Salmonella Typhi and Paratyphi A in the second quarter of the year, England and Wales: 1997 to 2006

Data for 2006 are provisional.

Intestinal helminths
In the second quarter of 2006, there were 51 reports of intestinal helminth infection, of which only three stated recent travel abroad. Of the three, two were Ascaris lumbricoides, of which one stated travel to Cameroon and the other to France; the other report was of Strongyloides stercoralis, which stated travel to The Gambia. Travel history information for intestinal helminth infection is under-reported.

Arthropod borne infections
Malaria
During the second quarter of 2006, there were 415 cases of malaria reported in the United Kingdom, 81% (335 cases) of which were caused by the parasite, Plasmodium falciparum (which causes the most serious, and potentially fatal, form of malaria) and 13% (54 cases) were caused by P. vivax. Fifty-six per cent of malaria cases caused by P. falciparum were reported to be acquired in west Africa, followed by east Africa (14%). Fifty-six per cent of P. vivax cases were reported to be acquired in Asia. Of all malaria cases reported, 21% (86/415) had no country of travel stated.

One particular report of interest during this quarter was of malaria caused by Plasmodium knowlesi in a traveller who had been to south east Asia. P. knowlesi is an extremely rare cause of malaria in humans; it is a primate malaria parasite whose hosts include crab-eating macaques, pig-tailed macaques, and leaf monkeys. It is transmitted by mosquitoes of the Anopheles leucosphyrus group. Natural infection in humans was first reported in 1965 in whom it resembles P. malariae. Occasional sporadic cases have occurred since then. So far, P. knowlesi has been found in humans in Malaysia, Malaysian Borneo, and Thailand [4].

Arboviruses
Ten cases of dengue fever were reported through the routine laboratory reporting system compared to only three in the same period in 2005; only one report stated recent travel (to Indonesia).

There were ten reports of chikungunya virus reported through the routine laboratory reporting system, all with no travel history stated. Routine reporting, however, underestimates the number of infections. Since the beginning of 2006, there have been 93 cases of chikungunya diagnosed by the HPA Special Pathogens Reference Unit as of the end of August [3], the majority of which were diagnosed during the first six months of the year. Most of these cases were associated with travel to the islands of the Indian Ocean (in particular, Mauritius).

Leishmaniasis
There were two reports of leishmaniasis in the second quarter; one of which was of the cutaneous type, with stated travel to Belize.

Other infections

Schistosomiasis
Sixteen cases of schistosomiasis were reported in the second quarter of 2006, ten S. haematobium of which one stated travel to Ghana, three S. mansoni all with no travel history, and three unspecified species of which one stated travel to Malawi.

Legionnaires’ disease
There were 63 cases of legionnaires’ disease reported in the United Kingdom (UK) with onset dates in the second quarter of 2006, of which 34 (including three deaths) were acquired abroad. This is a slight increase on the same period in 2005 (27/58 cases). Four of the travel-associated cases were involved in four separate outbreaks in Malta, India, Greece, and Spain.

Rickettsial infections
There were two reports of Rickettsia spp, one reported as Rickettsia spotted fever (but with no organism specified) with travel to Mozambique and South Africa, and the other was Rickettsia conorii (African tick typhus) with stated travel to South Africa.

Discussion
Travel history reporting is still disappointingly low, especially for some infections that do not occur in the UK but are prevalent in more tropical regions of the world, such as dengue fever, chikungunya fever, helminth infection, schistosomiasis, and leishmaniasis. Most of these infections are preventable by insect bite prevention measures or by other awareness and prevention methods. With increased travel by UK residents to more tropical regions of the world [1], it is important that information about the infections that travellers may acquire or be exposed to while abroad is collected so that appropriate pre-travel health advice can be developed for travellers themselves, as well developing appropriate information and advice that can be disseminated to health professionals who may see returning travellers (or new entrants to the UK) with unusual illness.

References
1. Health Protection Agency (HPA). Illness in England, Wales, and Northern Ireland associated with foreign travel – a baseline report to 2002. London: HPA, 2004. Available at http://www.hpa.org.uk/infections/topics_az/travel/pdf/full_version.pdf.
2. Office for National Statistics. Travelpac 2005 final. London: ONS; 2006. Available online at http://www.statistics.gov.uk/statbase/Product.asp?vlnk=14013.
3. Health Protection Agency (HPA). Chikungunya laboratory reports [online] [cited 27 September 2006]. Available at http://www.hpa.org.uk/infections/topics_az/Chikungunya/epidata.htm.
4. Jongwutiwes S, Putaporntip C, Iwasaki T, Sata T, Kanbara H. Naturally acquired Plasmodium knowlesi malaria in human, Thailand. Emerg Inf Dis 2004; 10(12): 2211-3. Available at http://www.cdc.gov/ncidod/eid/vol10no12/04-0293.htm.

Footnotes (body text)

* Co-Surv is the routine laboratory reporting system that collects laboratory reports of all microorganisms isolated at nearly 400 NHS and other laboratories throughout England and Wales. The database is managed and accessed at the Centre for Infections.

† Note that these figures refer to data extracted from Co-Surv only, and do not include cholera, S. dysenteriae , S .boydii , legionnaires' disease, malaria, Lyme borreliosis, or leptospirosis where data has been obtained from other sources.

‡ Labbase2 is the database that collects laboratory reports of all microorganisms isolated at nearly 400 NHS and other laboratories throughout England and Wales. The database is managed and accessed at the Centre for Infections.

Links to travel health websites