Although the development of early warning systems for malaria has been advocated by international agencies and academic researchers for many years, practical progress in this area has been relatively modest. In two recent articles, Thomson et al. provide new evidence that models of malaria incidence that incorporate monitored or predicted climate can provide early warnings of epidemics one to five months in advance in semi-arid areas. Although the potential benefits of these models in terms of improved management of epidemics are clear, several technical and practical hurdles still need to be overcome before the models can be widely integrated into routine malaria-control strategies

Abeku, Tarekegn A

Cox, Jonathan

English

LSHTM Research Online

Cox, J; Abeku, T; Beard, J; Turyeimuka, J; Tumwesigye, E; Okia, M;Rwakimari, J (2007) Detecting epidemic malaria, Uganda. Emerginginfectious diseases, 13 (5). pp. 779-780. ISSN 1080-6040Downloaded from: http://researchonline.lshtm.ac.uk/9588/Usage GuidelinesPlease refer to usage guidelines at http://researchonline.lshtm.ac.uk/policies.html or alterna-tively contact researchonline@lshtm.ac.uk.Available under license: Creative Commons Attribution Non-commercial No Derivativeshttp://creativecommons.org/licenses/by-nc-nd/2.5/LETTERS Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 13, No. 5, May 2007 779 Detecting Epidemic Malaria, UgandaTo the Editor: In the fi eld of ma-laria epidemic early warning, there ex-ists an unfortunate but frequently ac-curate perception that health systems in many affected countries learn of epidemics by way of the popular press rather than through formal disease sur-veillance systems. Malaria epidemics are often easily recognized (albeit too late) by laypersons (1), but most rou-tine disease surveillance systems lack the ability to provide accurate, timely indications of aberrations in case num-bers. The World Health Organization (WHO) has set specifi c targets for early detection and control of malaria epidemics as part of a wider strategy to cut the global impact of malaria in half by 2010 (2). We describe experiences during a recent epidemic in southwest Uganda and examine the performance of a pilot early detection system.In 2002, the Ugandan Ministry of Health began developing and piloting a new district-level malaria monitor-ing system in Kabale and Rukungiri (3). Located in Uganda’s southwest-ern highlands, these districts have ex-perienced several serious malaria epi-demics in recent years, most notably during the El Niño year of 1998 (4,5). In this new system, data generated from representative health facilities are collated, entered on computer, and analyzed by district teams on a weekly basis. Incoming data on clinical ma-laria are compared with a baseline of historical illness data from which the effects of long-term temporal trends have been removed, and an objective anomaly measure, or “standardized departure,” is used to provide a simple, intuitive index of deviation from ex-pected weekly levels of incidence (3). Electronic reports are disseminated by email to the National Malaria Control Programme (NMCP) and others, in-cluding WHO and the United Nations Children’s Fund.The monitoring system detected 2 malaria outbreaks in Kabale, 1 each in 2005 and 2006. During the most re-cent outbreak, the fi rst warnings of ab-normally high malaria incidence were communicated from the district team to the NMCP on June 5, 1 month be-fore reports of the outbreak appeared in the press and >2 weeks before case numbers began to peak (Figure, panel A). In the 6 weeks from May 29 to July 9, Kabale’s 5 sentinel sites re-corded 4,637 clinical malaria cases, 159% more than expected for this pe-riod. Although the sentinel network consists of health centers with limited inpatient facilities, available data on admissions showed a similar tempo-ral pattern, with 616 patients admitted during the same 6-week period, 188% more than expected.Although the ability of the system to generate timely epidemic warnings is encouraging, data from 1 sentinel site highlighted a potential limita-tion of using routine data from clini-cal diagnoses of malaria as a basis for epidemic detection. As elsewhere, routine outpatient data for Bufundi Health Centre suggested the occur-rence of a malaria outbreak starting in early June and peaking in early July of 2006 (Figure, panel B). The slight delay in the onset of the outbreak at this site was plausible, given its high elevation (2,200 m) and geographic remoteness. Data for patients with parasitologically confi rmed malaria, available through an ongoing malaria transmission study at Bufundi Health Centre (3), showed a different tempo-ral pattern of incidence, however. As Figure. A) Weekly observed and expected numbers of outpatient (OP) and inpatient (IP) cases of clinically diagnosed malaria from sentinel health centers in Kabale district, southwestern Uganda, May–August 2006. B) Weekly numbers of clinically diagnosed malaria cases and the proportion of case-patients subsequently testing positive for Plasmodium falciparum infection by rapid diagnostic test at Bufundi, Kabale district, southwestern Uganda, May–August 2006.LETTERS780 Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 13, No. 5, May 2007part of this study, all samples from ma-laria case-patients identifi ed through clinical diagnosis were subject to a Paracheck-Pf immunoassay test (Or-chid Biomedical Systems, Verna, Goa, India). Results indicated that, at the peak of the apparent malaria outbreak, the percentage of samples from clini-cally diagnosed cases that produced a positive diagnostic test was as low as 4% (Figure, panel B). These results are unlikely to refl ect poor diagnostic performance of the testing (6); febrile illness other than malaria was likely the cause of the outbreak.Recent experiences in Kabale also highlight the potentially unwieldy nature of indoor residual spraying campaigns in the absence of spatial targeting. In Kabale, a district-wide spraying campaign supported by the US President’s Malaria Initiative (7) was planned for the 2006 transmission season. However, shortages of trained personnel and other institutional de-lays meant that spraying could not begin until the third week of June, by which time the epidemic had peaked (and densities of vector mosquitoes had presumably begun to fall). By July 17, <50% of the targeted struc-tures had been sprayed. In the future, careful targeting of spraying to areas of highest epidemic risk might lead to more timely completion of spraying activities. It might also be benefi cial to create special spray teams that can respond quickly to specifi c alerts.Recent experiences in Kabale have underlined the potential value of simple monitoring tools for early detection of epidemics but have also shown potential barriers to effective epidemic control. Our fi ndings high-light the need to build systems that improve routine collection of data on parasitologically confi rmed cases of malaria and allow rapid investiga-tion of anomalies in incoming clinical data. It is equally important to develop procedures that translate early warn-ing information into timely decisions concerning which epidemic control measures to use and how best to target them (8). Without these procedures, the value of early detection will be seriously undermined.Funding for this research was provided by the Bill and Melinda Gates Foundation (through the Gates Malaria Partnership, London School of Hygiene and Tropical Medicine) and through the Department for International Development, UK.Jonathan Cox,* Tarekegn Abeku,* James Beard,* James Turyeimuka,† Enoch Tumwesigye,† Michael Okia,‡ and John Rwakimari‡*London School of Hygiene and Tropi-cal Medicine, London, UK; †Kabale Dis-trict Health Management Team, Kabale, Uganda; and ‡Ministry of Health, Kampala, UgandaReferences  1.  Nájera JA, Kouznetsov RL, Delacollette C. Malaria epidemics, detection and con-trol, forecasting and prevention. Geneva: Division of Control of Tropical Diseases, World Health Organization; 1998.  2.  World Health Organization/Roll Back Malaria. Malaria early warning sys-tems—concepts, indicators and partners. A framework for fi eld research in Africa. Geneva: The Organization; 2001. WHO/CDS/RBM/2001.32.  3.  Abeku TA, Hay SI, Ochola S, Langi P, Beard B, de Vlas SJ, et al. Malaria epi-demic early warning and detection in African highlands. Trends Parasitol. 2004;20:400–5.  4.  Lindblade KA, Walker ED, Onapa AW, Katungu J, Wilson ML. Highland malaria in Uganda: prospective analysis of an epi-demic associated with El Niño. Trans R Soc Trop Med Hyg. 1999;93:480–7.  5.  Kilian AHD, Langi P, Talisuna A, Kabagambe G. Rainfall pattern, El Niño and malaria in Uganda. Trans R Soc Trop Med Hyg. 1999;93:22–3.  6.  Mboera LE, Fanello CI, Malima RC, Tal-bert A, Fogliati P, Bobbio F, et al. Compar-ison of the Paracheck-Pf test with micros-copy, for the confi rmation of Plasmodium falciparum malaria in Tanzania. Ann Trop Med Parasitol. 2006;100:115–22.  7.  The US President’s Malaria Initiative. Lancet. 2006;368:1.  8.  Abeku TA. Response to malaria epidem-ics in Africa. Emerg Infect Dis [serial on the Internet]. 2007 May [4 Apr 2007]. Available from http://www.cdc.gov/EID/ content/13/5/681.htm Address for correspondence: Jonathan Cox, London School of Hygiene & Tropical Medicine, Department of Infectious and Tropical Diseases, Keppel Str, London WC1E 7HT, UK; email: jonathan.cox@lshtm.ac.uk Extensively Drug-resistant Tuberculosis, Italy and Germany To the Editor: Twenty-three countries have reported >1 case of extensively drug-resistant tubercu-losis (XDR TB) (1); however, in-formation about XDR TB is still in-complete. In particular, the response of XDR TB to treatment in countries with low incidence is not known. We compared mortality rates from XDR TB with those from multidrug-resis-tant (MDR) TB.We analyzed data from all cul-ture-confi rmed TB cases diagnosed during 2003–2006 by the TB clinical reference centers in Italy (Sondalo, Milan, Rome) and Germany (Borstel, Grosshansdorf, Bad-Lippspringe) and reviewed original clinical records. Drug susceptibility testing for fi rst- and second-line anti-TB drugs was performed according to World Health Organization (WHO) recommenda-tions by quality-assured laboratories and retested at WHO Supranational Reference Laboratories (Rome/Milan; Borstel) (2–4).XDR TB was defi ned as resis-tance to at least rifampin and isoniazid (MDR TB defi nition) in addition to 

Comparison of the Paracheck-Pf test with microscopy, for the conﬁ rmation of Plasmodium falciparum malaria in Tanzania. Ann Trop Med Parasitol.

Highland malaria in Uganda: prospective analysis of an epidemic associated with El Niño. Trans R Soc Trop Med Hyg.

Malaria epidemic early warning and detection in African highlands. Trends Parasitol.

Malaria epidemics, detection and control, forecasting and prevention. Geneva: Division of Control of Tropical Diseases, World Health Organization;

Rainfall pattern, El Niño and malaria in Uganda. Trans R Soc Trop Med Hyg.

Response to malaria epidemics in Africa. Emerg Infect Dis [serial on the Internet].

The Organization;

Early warning systems for malaria in Africa: from blueprint to practice.

Early warning systems for malaria in Africa: from blueprint to practice.

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