Changing patterns of malaria in south-east Scotland: implications for practitioner awareness and prophylactic advice

Clinical, geographical, and temporal risk factors associated with presentation and outcome of vivax malaria imported into the United Kingdom over 27 years: observational study

OBJECTIVE

To examine temporal and geographical trends, risk factors, and seasonality of imported vivax malaria in the United Kingdom to inform clinical advice and policy.

DESIGN

Observational study.

SETTING

National surveillance data from the UK Public Health England Malaria Reference Laboratory, data from the International Passenger Survey, and international climactic data.

PARTICIPANTS

All confirmed and notified cases of malaria in the UK (n=50,187) from 1987 to 2013, focusing on 12,769 cases of vivax malaria.

MAIN OUTCOME MEASURES

Mortality, sociodemographic details (age, UK region, country of birth and residence, and purpose of travel), destination, and latency (time between arrival in the UK and onset of symptoms).

RESULTS

Of the malaria cases notified, 25.4% (n=12,769) were due to Plasmodium vivax, of which 78.6% were imported from India and Pakistan. Most affected patients (53.5%) had travelled to visit friends and relatives, and 11.1% occurred in tourists. Imported P vivax is concentrated in areas with large communities of south Asian heritage. Overall mortality was 7/12,725 (0.05%), but with no deaths in 9927 patients aged under 50 years. Restricting the analysis to those aged more than 50 years, mortality was 7/2798 (0.25%), increasing to 4/526 (0.76%) (adjusted odds ratio 32.0, 95% confidence interval 7.1 to 144.0, P<0.001) in those aged 70 years or older. Annual notifications decreased sharply over the period, while traveller numbers between the UK and South Asia increased. The risk of acquiring P vivax from South Asia was year round but was twice as high from June to September (40 per 100,000 trips) compared with the rest of the year. There was strong seasonality in the latency from arrival in the UK to presentation, significantly longer in those arriving in the UK from South Asia from October to March (median 143 days) versus those arriving from April to September (37 days, P<0.001).

CONCLUSIONS

Travellers visiting friends and family in India and Pakistan are most at risk of acquiring P vivax, and older patients (especially those >70 years) are most at risk of dying; these groups should be targeted for advice before travelling. The risk of acquiring vivax malaria is year round but higher during summer monsoons, masked by latency. The latency of time to clinical presentation of imported vivax malaria in the UK is highly seasonal; seasonal latency has implications for pretravel advice but also for the control of malaria in India and Pakistan. A reduced incidence of vivax malaria in travellers may mean further areas of South Asia can be considered not to need malaria chemoprophylaxis.

Imported malaria in Scotland--an overview of surveillance, reporting and trends

BACKGROUND

Imported malaria cases continue to occur and are often underreported. This study assessed reporting of malaria cases and their characteristics in Scotland.

METHODS

Cases were identified at the study sites of Aberdeen, Edinburgh, Glasgow and Inverness. The number of cases identified in the period 2003-2008 was compared to surveillance databases from Health Protection Scotland (HPS) and the Malaria Reference Laboratory (MRL). Case characteristics were recorded and analysed.

RESULTS

Of 252 cases of malaria diagnosed and treated, an estimated 235 (93.3%) were reported to the MRL. Between 2006 and 2008, 114 of 126 cases (90.5%) were reported to HPS. Plasmodium falciparum caused 173 cases (68.7%). Business and professional travel accounted for 35.3% of cases (higher in Aberdeen), followed by visiting friends and relatives (33.1%) and holiday makers (25.5%). The majority of infections were imported from West Africa and 65.7% of patients for whom data on prophylaxis was available had taken no or inappropriate prophylaxis.

CONCLUSIONS

Reporting of malaria in Scotland can be improved. There is a continued need to optimise preventive measures and adherence to chemoprophylaxis amongst business travellers, those visiting friends and relatives, and holiday makers in endemic countries in order to reduce imported malaria cases.

Imported malaria: presentation and outcome of 111 cases

OBJECTIVE: To evaluate the presentation and outcome of imported malaria. PATIENTS AND METHODS: Retrospective charts review of hospitalized patients with smear-proven malaria from January 1989 to October 1994. RESULTS: Of a total of 111 cases, 95 were caused by Plasmodium falciparum. Chemoprophylaxis was used in 57% of patients but only 41% were compliant. Parasitemia ranged from 0.1% to 22%. Clinical and biological signs at admission were unspecific. In all cases where both platelets and C-reactive protein were measured, at least one abnormality was noted. More than two WHO gravity criteria were present in 14 cases. Outcome was marked by two deaths and 18 adverse drug reactions. Plasmodium falciparum was associated to only one independent factor in multivariate analysis: symptom onset less than 30 days after return. Chemoprophylaxis use did not modify clinical presentation, mean parasitemia or outcome. CONCLUSIONS: P. falciparum is the most usual cause of imported malaria in France. Normal platelet count and C-reactive protein value probably exclude the diagnosis of malaria in febrile travelers.